Spring has sprung the Moon is riz...

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Clear skies and improving temperatures brought me outside again with the CR150 6" F8 refractor on the MkIV mounting. The image still looked nicely sharp at 160x though I couldn't see any craterlets within Plato.There were some thermal, rippling effects. Probably because I was looking straight over the roof which had been warmed by almost continuous sun all day.

Here are some hand held snaps taken last night with my old Sony P71 set to infinity. I simply held up the camera to a 15mm Meade SP 4000 EP with the rubber eye cup rolled down. Then aligned the camera to get the maximum field of view on the tiny viewing screen.The telescope had already been sharply visually focussed and the Vixen 2" focuser locked. The drives on the MkIV were running. I normally wear reading glasses so there may be some slight loss of perfect focus for the camera.

A cropped shot of the one above. Plato is the large, dark-floored crater near the top. The sharp eyed will notice a slight greeny-yellow fringe at top left. This is a colour photograph, after all, despite the monochromatic appearance of the lunar surface. A Baader "Fringe Killer" filter was fitted in the eyepiece but visually I could still see violet on the limb at 160x. Though not in the lunar shadows. Quite a pleasing shot for a simple hand-held snap. I chose the best of about twenty shots then downsized it in PhotoFiltre for the blog. Click on the image for a 140kB enlargement.

Occasional vignetting is possible when using hand-held cameras at the eyepiece.

My attempts to use my much more sophisticated Panasonic Lumix TZ7 in the same way as the Sony was a total disaster, yet again. I'm wondering whether there is a setting which equates to infinity lock in the complex camera menus. Or some way of neutralising AF. I can't even get a reasonable image on the 3" focussing screen. Let alone a usable image to upload to the computer.

I must try to persevere with solving this problem because the TZ7 can manage very much higher resolution than the old Sony. It also has IS (Image Stabilisation) I tried several pre-programmed "modes" on the TZ7 but it made no difference. There is no need to experiment with the Lumix at the telescope in the dark. I can more easily try different settings on terrestrial objects with a small telescope on a fixed tripod. 

Meanwhile, Venus was a very bright colourful blob just dipping between the local larch trees. Mercury was already out of sight. Mars was just a tiny colourful blob but Saturn was much better. Being slightly higher than last time. The thin black line was even more sharply defined and several moons could be seen. The rings were more obviously open rather than a straight skewer piercing Saturn. The moons were not at all sharp or even continuously visible.
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Near Harvest Moon

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A shot of the moon at full zoom 12x on a hand-held Lumix TZ7 to check the IS. I have no idea what that fuzzy object is at the lower limb of the moon. Probably just a wisp of cloud, but you never know?  ;-))

I watched "Local Hero" on TV recently and was surprised to see a Fullerscopes reflector on a MkIV mounting. The instrument was supposedly in the possession of an astronomy-obsessed character played by Burt Lancaster. I would guess the instrument was one of their 10" Export Newtonians with a white painted tube. An interesting choice considering Mr Lancaster's character was supposed to be American and the filthy rich owner of an oil company in America.

I see Skylight Telescopes has another Fullerscopes telescope for sale. This time a 10" F:5 De-luxe reflector on a rather smart MkIII mounting with original pedestal stand:

http://skylight.myshopify.com/collections/frontpage/products/fullerscopes-10-f-5-deluxe

Buyer collects.

And another: An 8" F:6 on a MkIII again on a pedestal stand:

http://skylight.myshopify.com/products/fullerscopes-8-34-deluxe-newtonian

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12" Cass on a MkIV

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I had an email from the President of the Kent University Space Society seeking advice about an instrument in their possession. The instrument is a rather impressive 12" Fullerscopes, Cassegrain-Newtonian reflector on a MkIV with electric drives and large, Fullerscopes, plastic setting circles. The telescope appears to be housed in a high quality fibreglass dome.

The classical Cassegrain telescope uses a 'fast' concave paraboloid and a hyperboloid convex secondary to provide a long effective focal length in a fairly compact instrument. Fullerscopes used to offer a convertible Newtonian/Casegrain to make the instrument more flexible in application. This particular also appears to have a Newtonian focussing mount. The Cassegrain focuser is also visible behind the primary mirror cell. A simpler form of Cassegrain, known as a Dall-Kirkham, used the same optical layout of concave primary and convex secondary mirrors using simpler curves but could not be used (so well) as a Newtonian.

This instrument has fallen out of regular use and repair due to a lack of skilled personnel to carry out the necessary running adjustments and new observer training. Not an uncommon circumstance in the education field where there is a regular turnover of staff.

I was asked whether they should sell the complete instrument to purchase something newer. My advice was to start with the local astronomical society(s) in search of someone suitably experienced in a variety of telescopes. Hopefully they could offer expert advice free of charge or even make the necessary adjustments if the optical coatings were still usable.

An alternative to selling the whole instrument would be to keep the MkIV to carry a new OTA. Perhaps a compact Schmidt Cassegrain OTA from one of the popular US companies. No doubt savings could be made by buying a secondhand OTA which had been independently inspected prior to purchase. The existing Fullerscopes, hinged, tube rings could easily be replaced with those required for a new instrument.

The complete instrument may be up for sale but would be subject to cancellation if their plans should change. I recommended the UK Astro Buy and Sell small ads website if they wanted to reach the largest interested audience for their sale.

U.K. Astronomy Buy & Sell

It is difficult to see what all the wires and cables do from a photograph but there is a paddle and drives to both axes. The typical MkIV, bronze, 365 fine-toothed, slow motion wormwheels are clearly visible in the images. As are the Fullerscopes white plastic setting circles. A far more useful, if slightly less attractive, addition compared with finely engraved circle mounted on a slip ring on the RA wormwheel. The graduations of which require a powerful magnifying glass and reasonable light to read! The latter should be avoided in any astronomical observatory normally used at night.

If anyone in the Kent area has the real expertise to help with their instrumental problems they might like to get in touch with my contact: howard (at) phillips.fm

Note: I see this instrument and mounting are now both listed (seperately) on UK Astrobuysell seeking offers closing on the 14.9.09 no reserve. Be quick if you want a bargain. Collection only from Kent.

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Rebuilding my 5" F:15 refractor:

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I had wanted to rebuild my 5" F:15 refractor achromat into a telescope for some time. I made the lens probably three decades ago but it had lain dormant for probably the last half of those years. It needed a new tube, objective cell, mounting rings and a new focuser. The plywood original parts had disintegrated over time. The all brass replacement parts had proved far too heavy for me to lift above my head onto the MkIV mounting. Don't use recycled, artillery shell casings except for a permanently set up instrument!

Once the decision had been made to try again I quickly found a length of 6" galvanised steel, spiral ventilation tubing locally. This proved to be quite lightweight but very stiff though it lacked the flawless beauty of an aluminium tube. Then I made some plywood baffles with dowel stringers while I looked for a pair of modern, hinged tube rings online. I doubled up on 3/4" birch plywood to attach the push-pull cell. I also did a scale drawing to work out the spacing and diaphragm aperture diameters for the baffles. These I sawed out by hand using a fretsaw to rings marked with a screw bow compass. Only light sanding was required to tidy up the cuts.


This telescope has been a bit of an uphill struggle ever since and is taking far longer than I had anticipated thanks to postal and dealer delays. The tube size is not matched by any readily available (or affordable) tube rings. I find this completely unbelievable. Why is there such a big gap in the mass-produced "Skywatcher" type ring sizes just where one would assume a whole range of tube diameters would lie?

I quickly made a crude lash-up of 3/4" plywood just to be able judge the beauty of a long tube on the MkIV. I tried moving it around and took a couple of pictures.

Then I found a pair of 182mm hinged rings for sale on the "UK Astronomy BuySell" free ads website. Lined with thick, black, foam, self-adhesive tape these rings should match my needs nicely. The thick foam liners will absorb the spiral seam of the main tube.


The 182mm hinged tube rings have arrived. Now to find some thick, black, self-adhesive foam.

After struggling for years to insert ring screws into mountings and tighten wing nuts while supporting the OTA in mid air I will never go back to them again. Hinged rings are the only sensible way to go if dovetail wedges aren't available. These old Fullerscopes have nice long (and strong) cradles to carry the tube rings. So it's just a matter of dropping the bare OTA into the permanently attached rings and tightening the screw clamps. The tube is safely resting in the well-spaced rings while the captive clamp screws are tightened. What is more the clamping screws can be loosened slightly to allow rebalancing or rotation of the OTA.

My 90mm Vixen Custom 90 has captive, non-hinged rings fixed onto a matching dovetail. I still prefer to use hinged rings rather than fiddle with long screws through the MkIII cradle. An equatorial mounting cradle with rings already attached just needs to be pointed East/West to give a nice resting place for the OTA while the ring clamping nuts are tightened. I'm really not convinced a short dovetail and declination wedge is the equivalent of a long cradle attached directly to the declination axis for stiffness. The short dovetail on the Declination axis of a modern mounting must be under considerable local stress. This must lead to flexibility limiting the mountings usefulness with long telescope tubes. So the telescope manufacturers build ever shorter instruments despite their optical "difficulties". And so it goes round and around and around.

Meanwhile back at the 5" rebuild:

Now I needed a focuser. My original, 50 year-old, RAS threaded, push pull, brass focussing mount was bought with my paper round money when I was still an impoverished young teenager. (child slave labour was still acceptable back then) The brass focuser was bought for the first telescope I ever built. That one used a 1/2 diopter (2 meter focus) 60mm spectacle lens and some battens to make an "aerial" telescope. So it was about the finished length of my intended 5" F:15 once it has its dewshield added.

Fifty years later I really hadn't a clue what to look for in a focuser. They had already been fitted to the few OTAs I had bought so I had never been in the market for a commercial focuser. I knew I wanted 2" capability and a matching 2" dielectric star diagonal. The latter could share duties on my 6" CR150HD6 Celestron refractor. A (Japanese) Vixen 2" R&P focuser was mounted on my 6" Celestron refractor when I bought it secondhand. Though I wasn't sure if I wanted to move it over to the 5". The Vixen appears below and a big, rugged lump it is too. It's 80mmm (~3.25") focus travel has the capability to be fine tuned via tiny grub screws almost hidden in equally small holes in the main casting. The 2" dielectric star diagonal shown attached was remarkably cheap at £72 + P&P. I just hope it lives up to its promise. The fat end of the Vixen, where it fits the telescope tube tailpiece casting, is ~112mm (~4 3/8") in diameter.

Vixen 2" refractor focuser. (at full extension)

Now I had to look for a modern, commercial focuser and preferably an upgrade without any real idea what to look for. I began to search the many online astronomy equipment dealer's websites and was mazed how many 2" Chinese made Crayfords were available. The prices varied enormously but they all looked much the same with a few expensive exceptions. There were also a number of high end American eyepiece focusing mounts with mouthwatering finishes and claims but they would have run to many hundreds of £s by the time VAT and freight and customs had all been added to the inevitable range of upgrade options.

So I read the glowing reviews of the more affordable options on the popular amateur astronomy forums and was completely taken in. How could something so simple as a Crayford focuser go wrong? A tube, an axle and four bearings? I placed my order for one of the least expensive, 2" Crayford refractor focusers on the online market. Eventually, this is what turned up:

Inexpensive Crayford focuser sans skirt.

The finish was very impressive indeed for the price but the large, fine, ~3" thread on the bottom had me completely stumped. I had been told by the dealer that this large thread fitted a number of commercial refractors and popular SCT rear ends. It was years since I last saw an SCT and almost as long since I looked at an astronomy magazine. The actual focus travel of 56mm wasn't even close to the claimed 68mm either so I wasn't very happy. The GSO refractor focuser had a claimed 98mm of travel which is rather more useful for refractor use. Particularly when Barlow lenses and star diagonals are constantly being added or removed. This compact Crayford focuser certainly seemed smooth enough and the knobs did what they should. Though it would hardly carry loads which the 2" R&P Vixen would simply shrug off.

I spent the whole of the next two days searching online for a matching 3" female threaded adapter to fit the thread on the bottom of this focuser. How was I to know such a thing didn't exist? I emailed various companies without success and trawled endless websites. The images on the commercial websites were always too poor to recognise anything and the descriptions even worse.

Finally I found a well illustrated web page by somebody doing a lube and rebuild of a 2", slow motion GSO Crayford which looked just like mine. Except that it had a removable base to fit a telescope tube. That was the only clue I needed after two days of fruitless searching on the computer. My base was simply missing. That big, fine thread fitted nothing but the unknown manufacturer's own bases!

GSO Focuser

I almost placed an order for a suitably sized base from eBay but I had just emailed the owner of the website to thank him for his very useful article. Fortunately he was a knowledgeable enthusiast and immediately asked me for an image of my new focuser. He recognised my focuser was not a GSO but a cheaper Chinese copy. And what is more no GSO tube adaptor would ever fit it! The GSO has a plain cylindrical stub base which fits into the many different bases and adapters which match all the various commercial telescope tube sizes. I had been sold a "refractor focuser" with a rather short focus travel but without its refractor base. Luckily the dealer had a SCT cylindrical base which I will plug into a turned aluminium adapter flange/backplate of my own making to match my main telescope tube. Now I'm waiting on the post yet again for the SCT skirt. I shall use a 2" fitting drawtube to make up for the lack of focus travel.

The SCT skirt has arrived. The matching threads are shown above. Beautiful CNC work and very nicely finished. Sorry about my fingerprints!

The Crayford focuser now respectably dressed with an SCT skirt.


The 50mm (~2") SCT threaded end of the useful skirt is 82mm Ø. (OD) It offers a perfect flange to attach it to a turned backplate via small screws.

The finish is slightly shinier than the focuser body, but who cares? All I have to do now is turn an adapter ring to match the external diameter of the SCT skirt to the inside ø of my spiral steel main tube. Luckily I found a 24" length of solid 7" diameter aluminium bar in a scrap metal bin a couple of years ago. Equally fortunately I can get this huge bar neatly sawn into useful slices on a band saw by a local engineering firm. I'd hate to have to hacksaw a slice off the bar by hand!

A comparison of scale. 2" Crayford with 1.25" star diagonal & Vixen 2" R&P with 2" star diagonal.

This chapter will be updated regularly as the build progresses. In the meantime I have placed wanted ads online for another 2" Japanese Vixen refractor focuser. Until I find one this little Crayford focuser will probably do fine.

I have turned the adaptor ring in my lathe to a perfect fit in the main tube. (rubber mallet tight!) I was careful to take just enough material from the central stopped hole to obtain a wring tight fit on the SCT skirt. Both ring and focuser would probably stay in place indefinitely without fixing screws. Though I shall drill and thread some holes for fixing screws just to ensure they don't suddenly fall out on a very cold night! Differential expansion of the different metals involved might have this unexpected and undesirable effect.

The new tube rings temporarily fixed in place on the 24" long cradle are show above. It is amazing how the scale of the MkIV shrinks with a long OTA attached. Moving the tube around is very easy, with so much extra leverage, compared with the stumpy 6" f:8.


The black, ring-lining sponge I cut from an old camping mattress was a little too thin to get a really good grip on the telescope tube. So the tube tends to slide through them when it is pointed high in the sky! I didn't much like the look of white, double-sided tape I used either. I'm just going to have to look for some thicker, black, high quality, self-adhesive, sponge strip at the builders merchants. Closed cell foam would be best if I can get it.

Well, finding suitable self-adhesive foam strip proved impossible. So a search began for raw materials from which to cut suitable strips. Eventually I found a cheap garden kneeling mat in dense black foam at a supermarket.

Trials proved that 10mm (~1/2") strip was a suitable thickness to get a snug fit on the tube. After sanding my knife-cut strips, to ensure uniformity all round, I used a high quality, water based, contact adhesive on the foam and rings. I had already removed the original fibrous ring lining material with oil-based, house paint thinners. Which proved an easy and safe solvent. The idea was to expose clean, painted metal to ensure a good surface for the glue to adhere to. Trying to glue to the fibrous ring liner would have greatly increased the chance of the foam liners separating from the ring. The thickness of the new foam inserts easily absorbs the spiral seam of the ventilation tubing.

Now I need to turn an adjustable, push-pull cell for my 5" objective lens. I had better get a slice or two cut from the 7" diameter aluminium bar so I have something to work with. Brass is nice but would make the OTA as nose heavy as a modern Chinese refractor. I'm still not sure whether I want to add a larger diameter dewshield. A proper dewshield looks better than an extended tube of the same diameter. The difference between lens size and tube ID makes the choice optional. I had better make a decision before I start turning an inch or more off the outside of the 7" bar. In the meantime I shall use a plywood cell to speed things up. I have had to shorten the tube by another 10" (250mm) as the dewshield overhang was over 2 feet long once I had achieved focus with a star diagonal in place.

A shot of the 5" F:15 (now with 12" dewshield overhang) alongside the 6" F:8. The extra length of the 5" makes it much more unwieldy to carry around and getting it safely into storage. Conversely, the 6" seems to weigh twice as much as the 5"! You either accept or hate the spiral wound tubing. I prefer it to square sided box, plywood tubes. You make your own choice. I liked the low price compared with buying new, aluminium alloy tubing for this humble rebuild experiment.

Here are a couple of snaps taken with a digital still camera hand held to the 15mm Meade 4000 eyepiece. (no drives running on the MkIV so I couldn't lock the clutches)

The colour correction is excellent and the visual image far sharper than these images would suggest. The Moon was sailing along just above the ridge of the roof which has been heated by hot sunshine all day. The objective has been quickly aligned as has the focuser. Neither are fixed with screws yet. Both could do with more tweaking as there are obvious comatic/astigmatic images on bright stars. The spiral steel tube is slightly oval just where I want the objective cell and this is making alignment unnecessarily difficult. The Cheshire eyepiece showed multiple images no matter how I tried to push the plywood cell around at arm's length inside the tube! I didn't trust myself to try and align with the cell's push pull screws working blind. So I was nudging the cell with my fingertips against the tightness of the oval tube.

This alignment problem will be sorted out in daylight once the parts are safely fixed with screws. A shiny new aluminium tube is beginning to look very attractive right now! The popular irrigation tubing used in the USA isn't available in Denmark. So a new tube will have to be bought from a metal stockholder.

The inside of the tube, the adapter rings and baffles have not even been painted matt black yet. The rings of Saturn, despite the planet being quite low in the sky, were nicely sharp. With the rings in front of the planet a thin, hard black line. Needless to say I am very pleased with the results so far. Except for the focuser. Which fails to move no matter how much I adjust the screws. So it has to be pushed in and out by hand! You get what you pay for. Cheap crap in this case!

I did paint the baffles black but the new, aluminium, objective cell is still clamped in the lathe chuck.The drive belt keeps slipping so I can't get enough torque for a plunge cut.

I haven't done much practical astronomy this winter. It has been the coldest and longest, with the most snow, I can remember. Snow has been lying from before Christmas when we had 16".  It lay for 3 months in all! Permanently overcast day and night seems to be the norm. It has hardly risen above freezing for over two months! I can't even reach my telescope stand and couldn't move it through the deep, hard-frozen snow even if I could reach it. My workshop has plummeted to a steady -6C so there's not much going on in there either! 


Click on any image for an enlargement. Back click to return to the blog.




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Alejandro's MkIII with GOTO

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Alejandro is working hard on his MkIII to add GOTO using stepper motors.

He has also added some clever mechanical additions to aid fine alignment of his mounting on its pier. These fine adjustments will aid the precision of his telescope pointing and the accuracy of his drives.

The overall view showing original bronze wormwheel slow motions. The worms in their housings and what I presume to be a stepper motor resting on the workbench beside the mounting

Here Alejandro has used turnbuckles to allow fine adjustment of the polar axis altitude angle.

Some gears are also visible in this image. Presumably these will allow the slow motion worms to be driven by the stepper motors. He talks about pulleys so he may be using toothed belts between the stepper motors and worms.

Here is Alejandro's clever fine adjustment of mounting azimuth by finger power alone. I like the sheer style and neat simplicity of his approach.

Alejandro tells me in his emails that he is working on the electronic circuit board which will allow GOTO using popular sky mapping software. This is an exciting possibility which I wouldn't mind having on my own Fullerscopes mountings. I hope the complications of the circuit board are manageable by a relative novice at such things. We shall see.

I look forward to hearing more details as he makes further progress. No doubt more images will follow when he has the stepper motors in place on the mounting.

Anybody else who has applied GOTO to a Fullerscopes mounting is very welcome to get in touch so that the information can be shared with a wider audience: If anybody just wants to share an image or two of their own Fullerscopes telescope or mounting they are welcome to contact me.

Image size is of no importance since I can easily resize to match the needs of the blog. Since the Windows image resizer toy only worked with XP I am presently using the free VSO Image Resizer with Vista.

Many of these telescopes and mountings date back over 30 years so the present generation of amateur astronomers probably haven't much knowledge of this manufacturer or their products. Patrick Moore had a 15" made by them and there was an 18" German equatorial mounted Fullerscopes Newtonian at Charterhouse in the Mendips in the English West Country.

You can leave a comment on the blog or email me at chris.b (at) mail.dk with any information on Fullerscopes or images of their instruments.

AN UPDATE:

Alejandro has been in touch again and provided some excellent images and fascinating videos of his modified MkIII.

 Here the telescope is mounted on the modified MkIII. That is a substantial concrete pier.

A close-up of the MkIII showing the worm gear and toothed belt reduction drive from the stepper motor.

The modified MkIII seen from the south.

A short video showing the toothed belt driving the worm.

And another video showing the mounting moving in both axes to the software control.

Click on any image for an enlargement. Back click to return to the text.

Another 3" Fullerscopes Refractor

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Yet another 3" Fullerscopes refractor on a MkIII mounting. This one has the optional cast tripod base with the long wooden legs fitted. Note the height of the eyepiece. No grovelling on your knees with this one. Not like the "modern" refractors which assume you are a dwarf or have a dry moat dug around your mounting. The combination of black wrinkle paint and polished brass would look good in a drawing room. Yet it would be be very easy to carry it outside to examine a bright planet, the Moon or even the Sun when fitted with a safe solar filter over the objective lens. Eyepiece solar filters are extremely dangerous and may explode when exposed to the focussed heat of the sun. If the shattering glass of the filter does not instantly blind the observer then the focussed beam from the objective falling on the unprotected retina certainly will.

A general view of the instrument on its sturdy MkIII mounting and tall, braced tripod.

Look at the beautiful proportions! The length of the dewshield is appropriate and will offer protection on a night of heavy dew. The main tube is of classical length rather than the stumpy examples common to more modern instruments.

The all brass finder and focussing mount are classical touches. Note the excellent stand-off from the main tube of the finder in its tall, cast finder rings with centring thumbscrews. No squinting along the tube with your nose or cheek pressed against freezing cold metal required here. A glance at any of the fine refractors made by the greatest makers show similar finder rings. Many modern instruments could learn much from studying this instrument and others from a bygone age.

The original bronze slow motion wormwheels and steel worms are provided with flexible wands to allow easy centring of an object in the field of view from the eyepiece. The sturdy MkIII mounting would offer very stable viewing at the highest magnifications this instrument can manage. It is probably capable of upwards of 150x or 50x per inch of aperture.

The all brass focussing mount is furnished with an internal rack and a beautiful brass focussing wheel in classical refractor style reminiscent of instruments made one hundred years earlier. A star diagonal is fitted into the brass focussing tube for comfortable viewing at high angles of altitude.

The original black wrinkle paint is in superb condition. This particular MkIII even has its own model and the manufacturer's name resplendent on the polar casting. Letters also appear on the tripod base. My guess is that it also reads "Fullerscopes".

The three inch aperture, long focus, achromatic objective in its brass or gunmetal cell. A lens with a classical focal ratio will offer sharp images almost free of false colour.

Despite its age this instrument is still very desirable and would make an excellent solar telescope when fitted with a full aperture solar filter. The star diagonal will offer sharp, upright views but mirror reversed.

Once again I must thank Richard at Skylight Telescopes for these superb images.

www.skylightelescopes.co.uk

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Staying warm:

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Much of the following may seem patronising to those used to cold climates. As with all things you are completely free to ignore my advice. I have decades of experience in walking, climbing, cycling and camping in winter so I have learned the hard way. I started out by making my own mountain jackets and winter sleeping bags out of my old, Terylene wadding, summer, sleeping bags. Prices for serious winter gear were beyond my pocket back then. The downside was the the sheer weight and bulk of my kit and the unbelievable size of my rucksack! Now many sports clothes shops seem to sell high quality down-filled clothing and sleeping bags.

Temperatures are very subjective and only meaningful to the person experiencing the conditions. -3C with a biting wind in the UK is kid's stuff compared with Continental Europe or parts of the USA. That doesn't mean that the UK observer doesn't feel the cold and probably needs advice on dressing appropriately more than any other nationality. It does seem to be a native blind spot. While those blessed with Arctic conditions every year know exactly how to dress properly to match their own conditions.

Many amateur astronomers complain about being cold at the telescope. Yet there is absolutely no reason why they can't be toasty warm down to -10C with very little effort or expense. It's no use going out in a pair of jeans and a denim jacket expecting to be comfortable in cold conditions. Staying warm means you need both both insulation and protection from the wind. Insulation needs lots of thickness to function well by trapping still air. Still air is an excellent insulator. Moving air will chill you faster than much lower temperatures in still air thanks to something called the wind chill factor.

Wind proofing is best when it isn't also completely waterproof. Waterproofing usually means a high risk of condensation on the coated inner surface of the nylon shell if you so much as move a muscle. You aren't likely to be daft enough to try and observe during heavy rain so the idea is to insulate yourself with thick wadding or down within a light windproof shell. The shell is usually damp proofed, very finely woven, nylon cloth. Most down jackets I have come across seem to have a decent enough outer shell without adding another windproof jacket on top. Wearing anything tight or heavy on top of down clothing will compress it. Robbing you of its superb insulating power.

If you smoke you will soon regret wearing "proper" winter clothing. Because sparks from your cigarette or pipe will burn neat holes through the thin cloth like a hot knife through butter. Your precious down will start to leak rapidly through the holes you've made unless you patch them well and immediately. Good luck with that! So if you do smoke you'd better put a light cotton jacket over your expensive nylon shell. Did you know that smoking spoils and slows dark adaptation? Thought not. The flash of a match is unlikely to help you see faint fuzzies either.

Down filling has the advantage of allowing free and easy movement however thick the insulation. It also compresses really well. Down to almost nothing if you need to store or carry it. Thick wadding is often too stiff when you want to lift your arms to reach up to focus or make other adjustments. I won't give a wadding jacket house room any more. It's down every time. Smokers should seriously consider wearing wadding filled clothing to avoid the inevitable down loss from self-inflicted damage.

Down is usually very much lighter than most kinds of wadding and snuggles naturally around you. Being so flexible and compressible one can wear one down jacket inside another if conditions demand it. The advantage here is that even more still air is trapped between the two garments. The necessary seams to keep the down under control and evenly distributed are also very unlikely to overlap. So two thinner and lighter jackets can be as warm as a good single jacket.

The two jackets will be heavier and stiffer than a top quality mountain jacket but still offer superb warmth and flexibility in temperature control. The same goes for a down waistcoat under a down filled jacket. This is a really cosy combination I use a lot of the time. The problem with these superbly insulated clothes is staying cool enough if you exert yourself. Thankfully most observing means standing or sitting around for long periods with stable but comfortable temperatures inside your clothing.

Being a lifelong recycler and now living in a cold winter climate I keep my eye out for good used examples of down clothing in charity shops. I rarely need to pay more than £5-7 ($10-15US? Or equivalent) for superbly warm down filled jackets in clean, as-new condition. Having collected together a great variety of down jackets, insulated trousers and waistcoats I now have a wide choice. I dress depending on outside temperatures, wind strength and my subjective need for warmth. All of which vary widely.

Who cares about the slightly loose fit or the bright colour of the down/duvet jacket I'm wearing when I'm standing completely alone out on the lawn in my pitch dark, rural garden? Do I care that I look like the Michelin Man? No, I don't and nor should you. Dressed appropriately you will actually begin to enjoy the cold crisp nights and cool evenings at the telescope. You will spend more time observing. Instead of staying indoors to commiserate with other people complaining about the cold on the astronomy forums!

Thank goodness duvet jackets are now a common fashion garment thanks to their widespread use in the USA. When I started wearing my first, fat, down, mountain jacket in my youth people would stare at me on the bus. Remember the Back to the Future reference to the "life saver" when the hero was wearing a down waistcoat! A fashion garment in the wrong time period? My jacket was actually so warm that I usually had to take it off to stop myself from sweating buckets before I reached my destination. I was always experimenting with thermal underclothing back then to avoid the chilling effect of sweating indoors then going outdoors into the cold. It is actually far easier to simply take the jacket off indoors then put it back on when it is really needed! You can't argue with simple physics.

Down choice: Look for the vital garment label: Sometimes inside the collar or usually low down in the side the body lining under a sleeve position.

Given a free choice look for pure, thick, goose down rather than duck down of the same thickness. Goose down is warmer than duck for the same thickness. Look for wall quilting. Or double, overlapping quilting. Much better than the cheap sewn-through panels which are cold at the seams you see on cheap, fashion jackets. Look for high percentages of down to feather. Or pure down if you can find it. Feathers are very poor insulators compared with pure down. The feathers can easily be felt through the cloth shell with poor quality fillings. Squeeze the garment between your fingers to check for stiff quills. I wouldn't buy a lumpy filling like this at any price.

Pure goose down is very expensive when new but you should be able to find a good but very affordable jacket if you regularly monitor a number of charity shops in your area. People get fed up with the colour or the style and just give them away to charity shops. Students are fond of them so if you live in a university town you might have more luck in your search. Or more competition for the good stuff!

Older down jackets tend to start losing down from the seams which will cling to your black fleece wear. This may explain the large number of jackets I see in charity shops. Who cares if you look like you've been rolling in the snow as long as you are warm at the telescope? Give a secondhand down jacket a shake to see if it is shedding down badly before you decide that you can't live without it. One or two bits of down floating about is okay. A cloud of down is just not worth the trouble.

Beware that the law in some countries allows quite high percentages of feathers to down to be still called down on the label. Down has the unique ability to expand as it warms from body temperature. The superb insulation of pure down actually grows thicker when worn. Wadding just does what it does and slowly gets thinner from repeated compressions.

A down filled duvet is a superb choice on your bed at home compared with the stiff slab of wadding which falls off onto the floor all night. The down filled duvet wraps itself cosily around you. Closing off those chilling air gaps without weight. The same goes for down sleeping bags.

I managed to tempt my wife out of doors in a light frost to take the posed photograph below. No, I'm not the invisible man wearing a pink rubber glove! I deliberately obscured my face to maintain my privacy. Under all that down gear I'm as slim and as handsome as you are.

If you can't or wont buy at a charity shop and live in an area where there are climbing shops you could check out the down jackets there. Price tends to follow quality and lightness. The absolute best, super quality down fillings, light but incredibly tough shell and the way the filling pockets are arranged inside the jacket walls are inevitably expensive. These jackets have to withstand high altitudes, very low temperatures, very high winds, tearing and abrasion from climbing rock, ice and ice axes, crampons and ropes while allowing complete freedom for the wearer.. Things you hopefully won't concern yourself with on the back lawn. (where you usually have the choice of going back indoors to live another day!)

Compare prices at the climbing/outdoor shops with the rather heavier jackets sold at the high street fashion/sports shops. See if you can manage without the top quality mountain gear which always attracts a premium in price. Your wallet will obviously dictate your choice. Just don't buy anything too tight however rich you are! You need room for lots of clothes (or at least down waistcoat) underneath on the very coldest nights. Nowadays you can shop online but be sure of your sizing or ensure you can return goods which are too tight. A tight down jacket is worthless and will actually self-destruct as the seams are constantly stretched by your movements. You should hardly know you are wearing a good down jacket as it so light, snug, warm and comfortable.

I always wear a floppy Thinsulate (tea cosy) hat while observing because it is light and non-allergenic. It also stays on my head even if bend down to pick something up. Wool hats make me itchy. A soft hat can be adjusted to cover cold ears when it isn't quite cold enough for a balaclava. A lot of heat is lost from the human head in cold conditions. A baseball cap is a real nuisance at the telescope at night. It isn't remotely warm and the peak is always knocking against the finder. If you reverse it, street-cred style, the peak lifts the cap off your head as you tip your head back to look through the eyepiece. Save the baseball cap for solar observation where it offers some shade.

A balaclava is one of the warmest additions to your observing wardrobe in cold, breezy weather. Balaclavas can be pulled down to protect the neck and ears or worn rolled up into a floppy tea cosy. Sometimes I wear mine with the Thinsulate hat as well for extra warmth. Or both under the thick, down-filled hood of one of my duvet jackets if it is really biting cold and windy. Flexibility is the key. If you find yourself getting too warm while carrying your equipment across the garden to a new spot you can quickly remove your headgear for a rapid temperature loss without chilling your body.

Forget all about cold jeans even with thermal longjohns underneath. Fleece jogging trousers (or track suits) are available in many thicknesses and are far warmer. You can wear two pairs if sized appropriately. A slim, snug pair under a baggy pair offers superb warmth and windproofing without limiting your movements.

Then there are the light, wadding-insulated, over-trousers to wear on top of your long fleece pants. I'm not sure if these are intended for hardy golfers but I have accumulated several pairs to swap around depending on conditions on the night. Loose and baggy is best with these and it isn't a fashion parade anyway. They usually have elasticated waists so stay up even when bought deliberately oversized to fit over fleece trousers. Down filled trousers can be very warm but are easily compressed when sitting. Wadding is more resistant to compression and can be bunged in the washing machine without second thought. Down needs far more care in washing.

I have several down waistcoats which are valuable for extra warmth and offer great flexibility in heat control. I can open my jacket if I get too warm and the waistcoat maintains body heat. Or I can open the waistcoat as well to cool off rapidly when necessary. I can keep eyepieces in the waistcoat pockets if conditions are leading to rapid misting. The eyepieces are then rotated through my right jacket or waistcoat pockets. My compact digital camera always sits in the big left hand jacket pocket to avoid internal condensation. Developing habits like this ensure nothing expensive gets broken by dropping several things at once into a deep pocket.

Gloves are a complete pain in the "wotsits" because they deny fine dexterity for tightening those daft little draw tube or star diagonal eyepiece clamping screws! I am usually warm enough to do without gloves because I protect my core temperature properly. A warm body does not draw heat away from the extremities to survive. So your hands and feet usually stay nice and warm. Beware of very cold metal welding itself to the bare skin of your fingers though! A little moisture is the danger here. Plastic focussing knobs are actually far more practical in winter than fancy, expensive metal ones! Rubber sleeves on the focussing knobs no doubt help here but why bother when plastic is so superior? Down jackets usually have large hand warmer pockets anyway once you have the object centred in the field of view.

Hiking boots are better than ordinary shoes and far better than trendy trainers. You need plenty of room for thick winter socks so don't buy boots that are too tight. It's not a fashion parade alone in the pitch dark. Rubber Wellington boots aren't ideal but may be useful in deep snow. I find them too cold.

Staying comfortable is the trick. Get too warm and you'll sweat too easily under all that insulation. Which means it will feel like an ice cold bath when your own sweat suddenly condenses against your skin through your wet vest or t-shirt. If you feel yourself getting too warm you must open up your jacket, take off your hat or lose heat somehow. Don't ignore the first feelings of getting too warm or you will suffer far more than simply being too cold.

Going back indoors to download your camera, or to look at a star map, will cause you to rapidly overheat. Make a habit of taking off the jacket and hat or you'll feel really cold when you go back out again. If you start to feel cold when outside do some exercises in small doses until you feel pleasantly warm but never hot. You must avoid sweating at all costs so your undergarments stay dry and warm.

Keeping the telescope comfortable:

I find anything below about -10C begins to make life difficult at the telescope. Many plastic insulated cables stiffen up in the cold. The slightest breeze rapidly increases the wind chill factor. This is where observatories score highly against standing out on an exposed lawn or yard because they offer shelter from the wind. A dome reduces your own radiation to the night sky and offers the most wind protection. They also have thermal issues from boy heat escaping through the open slit. Just where you are trying to look through with your telescope!

A roll-off is better still and provides shelter from the wind. Even a slight breeze increases the wind chill factor dramatically. If you have a permanent site in the open garden it would be worth putting up a few fence panels and strong posts to shelter you from the prevailing wind. Hedges take too long to grow into a decent shelter belt and are poor windbreaks in winter anyway. I know this because my garden is surrounded by tall trees and tall hedges and it is often still very windy out there.

Cold eyepieces may steam up from the moisture of your eye. Or dew up from your breath if you don't deliberately direct it away. When you are breathing through a balaclava it isn't so easy to keep the eyepiece clear of dew. I pull my balaclava down under my chin and breathe downwards through my mouth to avoid fogging the glass. Keeping eyepieces in a pocket allows your body warmth to keep them far warmer than in an open box or rack. On dewy bights an open rack or box will soon get very wet.

Residual moisture inside the OTA can fog up a refractor objective inside where it can't easily be reached with an electric hair drier. This has ended a couple of my very cold observing sessions in the past. A good long dew shield helps to keep the glass just above the ambient air temperature. Most modern refractors have woefully inadequate dewshields. I'm sure they are styled like this just to make them look short and stubby like the ultra-expensive Apos. (Apochromatic refractors)

Just roll some black, closed cell, camping mattress around the original dewshield to double its length and hold it in place with a bungee, string or even thick rubber bands. The foam will act as an insulator as well as improving your telescope by having a proper light and dew shield. I'm often surprised how my neighbour's security lights will fog the field of view. Even when the telescope is pointing away by quite a large angle. The matt black paint inside the skimpy, Chinese dewshield of my Celestron 6" refractor is obviously not all it should be! Thin, black, closed cell foam from craft shops is good value when used as an anti-reflection surface inside the dewshield . No doubt contrast could be further improved by applying it elsewhere inside the OTA.
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A 3" Fullerscopes refractor.

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Here is another Fullerscopes telescope. A 3" refractor sitting on a sturdy MkIII. The mounting has the optional cast pot base fixed on a tall pipe pier fitted with the standard, light-alloy, Fullerscopes, cast pedestal feet. Ready to use in an instant without any cooling down required. No grovelling on your knees to reach the eyepiece when the telescope points at high altitudes. No wobbly, undersized, aluminium tripods designed by somebody who has never seen a real telescope. Let alone actually used one. Those who have designed the inadequate mountings and tripods of the 1990s should be forced to use them as penance for their utter ignorance of what really matters under the night sky. Rock steady stability, easy pointing and following are the only the most desirable features. What about the eyepiece always being comfortably placed for the observer regardless of the position of the object under scrutiny? One hundred years of nightly use of their pathetic wares is punishment enough for those churning out today's astronomical tat. Do they think there is nothing above 30 degree altitude worth looking at? A star diagonal is a vital component with any refractor but assumes you can still reach the eyepiece. And do so without silly contortions or constantly muddy knees! Listen to ignoramuses on the astronomy forums telling you that refractors are neck wrenchers. You'll instantly recognise the owner of a modern instrument.

This size of telescope was a very desirable instrument in my youth. A 3" refractor was considered the minimum size for a serious astronomical instrument. Yet a remarkable amount of serious work was carried out with instruments of this size and smaller apertures in the 18th and 19th and well into the 20th Century. Smaller apertures were often used in the days before Chinese mass production brought aperture fever and relative affordability to the ordinary amateur astronomer.

The vast majority of these older instruments were of a so-called "classical" focal ratio. Meaning that they had a very long focal length relative to aperture. F:15 was considered normal. F:18 not that rare. Some instruments ran to much longer focal lengths with F:Ratios well beyond 20:1. The aim was to improve the image quality by reducing the natural false colouration of achromatic aberration. This cannot be avoided in an ordinary flint and crown doublet achromats. Only special dispersion glasses like the so-called ED glasses and the costly Fluorite can remove false colour almost completely. The "slower" the optical system (using the photographic term) and the smaller the aperture the less false colour would be seen in the image by the visual observer using an ordinary achromat. Photography was not a serious pastime with such instruments and the field of view was very small anyway. Film was much too slow or too grainy to capture the relatively dim images on extended objects like the Moon and planets. So they were used visually almost exclusively. Usually they perched on a tall, sturdy, well-designed, wooden tripod. Often fitted with an altazimuth, offset fork rather than an equatorial mounting. The latter was usually reserved for the larger instruments. Which were not so easy to move about and so needed and enjoyed a stable cast iron base for their heavy steel, tin or brass tubes of the time.

What most of these refractors had in common was the ability to push the magnification to the maximum possible for the aperture without the image "breaking down" into a fuzzy ball of light. 50 magnifications (power) per inch of aperture is considered a reasonable maximum for most instruments. A good, long focus refractor might be pushed to 100x per inch of aperture and sometimes well beyond on a good night when the air is perfectly still. The best objective lenses were slowly polished on pitch using the finest optical rouge to obtain a flawless, highly transparent, spherical surface. No doubt the Chinese objectives of today are polished at the highest possible speeds using paper, fibre or cloth laps and rapid but coarse cerium oxide polishing compounds. Thus leaving a much rougher surface due to surface heating effects. I'm a bit out of touch on modern, mass production optical fabrication. So I may be completely wrong.

I watched elderly optical workers just before their retirement back in the 60's and was amazed at their skill and dexterity. They knew by instinct when a surface was no longer spherical or was growing too short or long in radius of curvature and adjusted accordingly. Their movements were precise and entirely automatic with absolutely no excessive gestures or wasted energy. It used to be said that optical workers could be followed home by the trail of red rouge they left in their path. These highly skilled gentlemen were already using Cerium Oxide by then.

Smaller apertures have another serious advantage over larger instruments. They look though narrower "beam" of thermally unstable air than a larger instrument. This makes the image more stable and able to be used with higher powers in inferior "seeing". Which might even make a larger instrument unusable on some nights. For double and variable star work these small instruments were, and are, still fine. Stars do not change in size depending on the size of the telescope. No matter how large you make the telescope or how much they magnify. These small refractors could give a nice view of the moon or the planets. Though it takes a bit more aperture to get really large, sharp images for the illusion of hovering above the Moon's surface. For double stars the high magnification was necessary to split close doubles with such a small aperture. The telescope can magnify the separation between double stars but not the size of the stars themselves. There is a limit on how close a double a particular instrument aperture can manage. Fuzzy star images make separation more difficult because the stray light blurs and bleeds into each separate star. Closing the gap between them. Instead of a nice clean separation with distinct stars and inky blackness between them. Experts still use selected double stars to confirm the optical quality of telescopes under test.

Just look at the length of that dew shield! It fits on the front of the objective cell where it should be. Not hiding the cell half way down the dewshield. As is very common of many commercial refractors today. They do this just to give the illusion that the telescope is shorter than it really is. Perhaps even suggesting it might be an expensive APO? What a total con! What a cheap conjuring trick! The objective gets covered in dew within half an hour of going outside. Believe it or not, specialist firms now make real dewshields to properly protect the glass. By making them long enough and light enough to actually do their intended job. How pathetic is that? A dewshield which isn't anything of the kind? Some dewshields are made of steel which is heavy and unbalances the telescope tube. Making it look as if it has slipped through the rings to finally stop at the cell before it could slip right through onto the ground. Have a look at my 6" F:8 Celestron on the MkIV if you want to see a perfect example of this horribly ugly imbalance. Now look at the 3" and 4" Fullerscopes refractors show here. They stand tall and proud on their mountings like the giant refractors at the great observatories. The shorter the overhang at the eyepiece end of a refractor the smaller distance it covers as the telescope moves through the entire visible hemisphere of the sky. That is worth having because you don't need to keep shifting yourself around the mounting. Wearing out the grass over a large circle. The shorter the overhang at the business end the lower the pier or tripod can be without the eyepiece "scraping on the ground". So the modern refractor is not only a double sales con to impress the beginner. It shoots itself in both left feet. Or all three if you prefer. By making the eyepiece far too low for comfort, dewing up rapidly and making the telescope look downright ugly instead of incredibly impressive. Everybody loves a tall refractor soaring high into the air. It looks like a real astronomical telescope is supposed to look. How does yours look?

Manual slow motions are fitted to both axes on this mounting. Only the polar axis has a flexible control. These universal "stalks" are easily available from astro-equipment vendors if it was thought desirable to add one to the declination axis. Note the solid bronze slow-motion wormwheels. You'll be lucky to find hard-wearing bronze wormwheels on any mounting made today that doesn't cost much the same as a new car!

A small synchronous motor could easily be fitted to the polar worm shaft to enjoy relaxed viewing. I find a motor drive makes observing so much more enjoyable. Instead of having to move the telescope by hand all of the time. Particularly at high magnifications. When an object is rapidly crossing the field of view it is difficult to keep it on the "sweet spot" in the centre of the field of view. You don't even get a chance to focus your eye on the object to see the fine detail before it has gone right out of the edge of the field. A motor also allows you to leave the telescope to follow an object while you do something else. Like downloading your latest images into your computer from your digital camera to check your results so far and warm up a bit indoors. My MKIII drive motor died recently just as I wanted to use the mounting to record a partial solar eclipse. I was amazed to have caught anything with my digital camera while constantly having to turn the slow motion control by hand. Or even nudge the tube between taking my hand-held "snaps". The results of my solar eclipse photographic endeavours can be seen in another chapter under "Transits and eclipses".

The instrument looks beautiful in black wrinkle paint with polished brass fittings. Fullerscopes used to offer an "Export" model of each of their telescopes in this very desirable finish. The brass focussing knob on this 3" has been moved to the lower part of the main tube. A popular position on many classical refractors from the golden days of "brass and glass". I'm not sure about the length of the Polar Axis on this instrument. Perhaps the shaft has been swapped for a better one? It loks as long as the Declination shaft ought to be. My own MkIV has an over-long polar shaft because I haven't cut it in case I need the extra length for something.

The brass finder telescope in its tall, cast, adjustable mounting rings sets off the instrument perfectly. None of your modern spring-loaded finders flopping about as the main instrument is moved. Plenty of room to use the finder wherever it ends up relative to the main instrument as it is moved around the sky on its German equatorial mounting. Modern finder rings are often far too close to the instrument and lose their view simply by being blocked by the mounting. Or cause such gyrations of the neck that it might as well not be there. A good stand-off distance is essential for finder comfort and practical functionality. Look at the great refractors of the observatories and see how tall the finder rings are on those beauties. With two matching finder rings you can also set-off the finder to a nearby star. For example when you want to photograph a dim object which is invisible in the smaller finder.

White gloss painted tubes seem to have become the latest fashion in telescopes. I suppose it makes them easier for the clumsy to miss them in the dark. My tastes are from a period when black wrinkle paint was a sign of luxury. The manufacturer showed he was going the extra mile instead of using plain gloss paint. Wrinkle paint does not show fingerprints, scratches or chips so readily either. It was hard baked on and lasts better than gloss. (or Hammerite for that matter)

This MkIII is fitted with the original, large, white, plastic, setting circles. An excellent combination of clarity, longevity and nice, big graduations. No magnifying glass and bright torch required here to point the telescope at an object using the Right Ascension and Declination coordinates. Look at the size of those setting circles compared with the microscopic graduations seen on small bands fitted as an afterthought to many a modern mounting. Notice the size of the shafts and massive yet lightweight castings compared with the tiny things on offer with many telescopes today. I wonder how many modern mountings will be valued as useful bases for telescopes in 20 or 30 or 50 years time. There is simplicity and strength here allied with function. Many modern mountings suggest the triumph of appearance over functionality and stability. You'll not find the owner having to modify a Fullerscopes mounting just to make it stable enough to use with the usual oversized instruments sold today. Sand filling short, wobbly, aluminium legs and removing useless Chinese grease is not required.

Set up on a tall pier a refractor makes perfect sense in the observer comfort stakes. How many forum threads have you read about adding weights to the eyepiece end of a modern refractor OTA? Just to be able to look through the instrument without having to empty the swimming pool or goldfish pond. Or digging a deep hole. Anything to bring the observer to a lower position so they could actually look through the eyepiece without lying flat on their back on the wet grass. And they call this progress? Don't moan to me about your wobbly knee-high, aluminium tripods. While simultaneously sneering at tall wooden tripods as being "too old fashioned". Nobody can see you observing in the dark whatever your tripod material. Anybody using a tall pier or tripod is going to be doing a heck of lot more astronomy than you with your highly-polished, metallic jelly. And how much did they charge you for that crappy tripod anyway? You could build a decent, tall tripod out of quality hardwood for a fraction of the price. Or sink a simple pipe pier into the lawn. Get yourself an adjustable height chair and you can observe in perfect comfort for hours on end sitting down. You'll need a properly balanced refractor fitted with a star diagonal of course. You wouldn't be daft enough to buy something you couldn't actually use on the whole sky, would you? That wouldn't be an astronomical refractor. It would be a terrestrial. Or a common or garden bird watching telescope but with an inverted image. Wouldn't it? That's what I thought too.

Protected from the elements a refractor and Fullerscopes mounting will give decades of enjoyment exploring the night skies. It becomes an heirloom instead of an irritating burden to be discarded as soon as the doting grandparent goes off into the old people's home. No need to cover and worry about dew and scratches on delicate aluminised reflective surfaces with a refractor. A refractor will last virtually forever without deterioration. The glasses used varied a bit but only slight yellowing occurs over the centuries with some of the the older glasses. They tended to be designed to achieve best focus more towards the yellow. Instead of the yellow green of today's computer-optimised prescriptions. We may be spoiled rotten by cheap APOs and large achromats these days but the sharpness of the image seen through a fine, small refractor is well worth seeing. Perfect star images on either side of focus with textbook diffraction rings are to be expected. A lightweight, compact tube to carry out to the pier or tripod. Where the mounting is already set up and aligned on the Pole Star for instant use. Open the rings. Pop in the telescope, tighten down gently on the thumbscrews and you can start observing immediately.

The images in this chapter were kindly supplied by Richard Day at Skylight Telescopes of London. A vendor of collectible, quality instruments for the discriminating observer who is not fooled by this year's glossy, full-colour advertising spread in the popular magazines. I'm beginning to sound like an advertising man myself. As well as an opinionated, old .. observer.

www.skylightelescopes.co.uk

BTW: The beautiful instrument illustrated here has been sold.

The images in this chapter are not yet clickable for enlargement. Patience will be rewarded.

Fullerscopes 4" Refractor.

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Here is a complete 4" Fullerscopes refractor on a MkIV mounting sitting on a heavy pipe pier with original cast iron "heavy duty" feet.

Fullerscopes usually offered their 4" refractor on the MkIII. This one enjoys the great pondus, stability and sheer class of the timeless MkIV.

A closer look at the 4" OTA (Optical Tube Assembly) on the MkIV. This achromatic refractor is longer than many of the Chinese offerings of today. Theoretically this provided sharper images with less chromatic aberration and coma. Another advantage with long focal lengths is the ability to use comfortably long focal length eyepieces while still enjoying high powers. This in turn offered increased eye relief without one's eyelashes smearing the surface of the eye lens or obscuring the edges of the field of view.

Now there's a nice point of view! Lots of polished and lacquered brass and black wrinkle paint. Fullerscopes made the classical rack and pinion focussing mount in the same style as the great 19th Century makers. The heyday of brass and glass when makers vied with each other to produce microscopes and telescopes for those who could afford them. The upper and middle classes were the only customers who could afford such luxuries back then. Beautiful refractors like that shown here would grace stately homes and doctors, lawyers and bankers detached, country homes. This may not have been strictly true of Fullerscope's products but they still required a considerable investment for that time. Prices for refractors have fallen dramatically in recent years as Chinese products overwhelmed home markets for these instruments.

These much earlier instruments could also be found in the fee paying (public) schools of the wealthy. The telescopes were often housed in domes like the one shown above which protected a 5" classical refractor in the grounds of a public school. An all brass 6" refractor was stored at the same school but had suffered a broken crown element in the objective lens. The workmanship of the entire instrument was of the quality which only the very best makers could manage. With lots of intricate brass and bronze castings all skilfully hand finished and deep gold, hot lacquered to maintain the superb finish for a lifetime and well beyond.

Another view from the business end of the 4" Fullerscopes refractor. The counterweight might be improved to be more in keeping with the perceived quality of the instrument by fitting a simple, cylindrical, bored turning in steel or iron. A few minutes work for anybody with a lathe and the raw materials.

A closer view of the mounting showing the 6" bronze wormwheels and slip-ring RA circle with metal pointer. These are presumably of a later date than my own MkIV. The main castings were designed to maximise stability by using widely spaced sleeve bearings supplemented by large surface areas on the thrust faces. PTFE sheet was used to reduce friction between these faces. Offering a light, buttery smooth motion without backlash provided the telescope is not too massive. The MkIV could carry up to 15" reflectors but friction may have increased beyond the comfort level when fine pointing the telescope by hand. These castings look rather rough suggesting that they have been cleaned up with a very coarse file by somebody in a hurry.

The large plastic knob jutting from the declination casting actuates a simple clutch via a long screwed rod. This forces a nylon plug against the inside of the relevant wormwheel. There are two knobs. One for each axis. The slow motion worm housings look rather later than my own and these seem to have evolved over time.

The beautifully tapered main castings are strictly to the book. Maximum stiffness where the loads are highest. Reducing in diameter where the loads are least. Russell W Porter, the brilliant designer of the 200" Hale Telescope, suggested this arrangement in his designs for the castings of telescope mountings used prior to the erection of the Hale Observatory. These (and others) were shown in the classic three volumes of "Amateur telescope Making" published by Ingalls around the middle of the last century and earlier. These books can probably still be found in major libraries and specialist bookshops. Particularly those with online search facilities. They are now rather dated but full of useful information for the creative amateur astronomer. Particularly one who likes to build and make things for themselves.



The lacquered, adjustable brass cell showing the first surface of the achromatic objective. (below) It is believed that Wildey was responsible for Fullerscope's refractor objectives. His work is legendary and, if he really was the maker, probably resulted in a very fine lens.

The massive cross sections of the MkIV mounting provide the stiffness and resistance to flexure so essential to real telescope mountings. The eye may be quite forgiving of wobbly mountings but can these cope with photography or imaging? No problem here.

An unconventional view of the instrument. Perhaps the one seen after one has just fallen off a high stepladder while trying to view something near the horizon? ;-)

What is there not to like about this classical refractor on a sturdy, well-designed mounting?

My gratitude for all the images above goes to Richard at Skylight Telescopes of London. I have enlarged his original images in Photofiltre to allow closer views. Any faults in the enlarged images are entirely my own. Richard is a specialist vendor and restorer of quality, older instruments. His website is well worth a visit for those with an interest in instruments of the last century and beyond.

www.skylightelescopes.co.uk

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