Observatory: More handrails and red lghts.

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Tuesday: Grey, windy and wet. Made a larch threshold board for the main doors. Fitted a bolt to the outer door to hold it shut and then painted both doors with Safe-Way, mineral wood protection to darken them.

The Head Gardener has suggested I add a larch "skirting board" plinth[?] right around the outside bottom of the octagon. This will help to seal the bottoms of the plywood panels against intrusion by the local wildlife. Not to mention making it look smarter and more finished.

I'm still happy with the sage green of the dome. It changes constantly with the light, dew, frost and rain but always remains pleasant to my eyes. Even The Head Gardener approves.

Wednesday: Blustery with short showers. Wired up the red bulbs and then spent time making more handrails. They look more convincing when a whole row is visible. Only the two shortest ones nearest the shed to do now.

The red bulb inside the pier was superb. It gently lights the steps and the closed trapdoor. Confirming that the hatch was safely closed is a real breakthrough in confidence building. Exactly as needed but a direct view of the naked bulb still doesn't blind me.

Some red light also leaks out around the pier base where there is an isolation gap with the floor. Which is excellent for delineating the exact place of everything in the dark. Yet the the light is actually so dim that it doesn't register in the camera. My 'snaps' I took of the red light leakage were pointless. Nothing showed up!

Later, Mars was low to the south again. So I set up to have a look. Whereupon it soon clouded over. I need more light in the observatory for setting up without using a torch. I went out onto the veranda to see if the Moon was visible without having to turn the dome. To discover the light wood of the  handrails made it much easier to find my way around in the dark.

The channel section larch handrails have really increased the stiffness of the fencing. It feels really solid now. Rather than merely being amply strong enough for the job. So all the work in precision grooving the undersides to fit the doubled fence top bars, with a router, was well worthwhile. I still need to treat the handrails to prolong the life of the wood and then sand them well. The steel posts should really be bolted to the woodwork too. Yet another roundtoit. I ought to make a list.

Click on any image for an enlargement.

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Observatory: Lights and secure doors.

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Monday: The Xmas red LED lights arrived and proved to have a fault. Tipping the control box, with solar panel, makes the lights come on or go off. Grr. I whipped the back off and had a peek but there is nothing obviously wrong or loose. I'm wondering whether I can bypass the unwanted gubbins but there must be more to it than that.

Update: I have just discovered the LED's control box has a night/day sensor but does not mention it. Simply covering the solar panel switches the lights off even when the battery is charged.

I could return them for a replacement but it's so boring for a £20 set of Xmas lights! They worked exactly as desired for low light intensity and perfect length of the string.[Wire.] Lots of flashing modes add that certain something, if you like that sort of thing. Though the Santa's Grotto effect is probably best avoided IMO if you want to be taken seriously in this hobby.

Today I slid the OTA upwards through the rings enough for the dewshield to just clear the dome. This gave me about 3" more clearance from the octagon's top ring when the OTA is almost horizontal. Still far too little room without a star diagonal and even then a struggle at times.

As it was dry but cold and windy outside I spent some time working on the main doors. Still not sure what kind of lock I want. Galvanized stable latch and a matching padlock? Or posh, lever handles and a real key? Or none of the above. I could always sit at my bedroom window monitoring for burglars with a machine gun on my lap. "Are you feeling lucky, punk?" That sort of thing. It could be a long wait. This isn't Gravely Blighted, after all. Anyone hoping to find any valuable instruments, cameras or upmarket accessories in my observatory will be sorely disappointed.

What about a grenade with a bit of string tied to the door handle? Nah. I might forget it's there and spoil my whole day. You know what I'm like. Same goes for boiling tar vats at the top of the stepladder. Just think of the expense in quarterly fuel bills?

I think I'll settle for a deafening alarm and flashing lights inside the building. With a self-closing, self-locking door once they are safely inside. What's that, Mate? I can't hear you! Can you speak up, please? 🙉  I thought I might add a Doberman, or two to the disco mix, but won't risk damaging the innocent creature's ears.

Went over after dark to properly check the red LED lights. They now seem to be working normally but provide very little useful light. Precise location of the dome perimeter is about it. Rather than adding any extra light to the observatory. It was impossible to see the telescope parked horizontally just above me.

I could face all the lights inwards or upwards if I used cable clips. At the moment about half are facing outwards or upwards. It might be possible to use a proper stapler instead of cable clips. Probably best done in daylight. It's pitch black, blowing a gale and raining right now.

I also bought a couple of small, red, 1W, LED bulbs with standard, mains, light bulb fittings. Then discovered I had no spare light sockets to try them out in the observatory. I thought I could hang one bulb in the "dog kennel" inside the top of the hollow pier. That would gently light the stairs and wash over the closed trapdoor for confirmation that it really is closed. I couldn't relax in the dark with the risk of the trapdoor still being open. I'm a martyr to short term memory loss. I'm a martyr to short term memory loss.

Click on any image for an enlargement.

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Observatory: Going live: Goto drive troubles NOW FIXED!

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Sunday: 32-40F sunny: I spent a very cold day sitting in the observatory trying to get the ASCOM AWR drive to work. StellariumScope shows the correct configuration but nothing shows or works in Stellarium. Similarly, Cart du Ciel shows the correct AWR ASCOM driver and "connects" but again there is no visible or audible response to mouse clicks for telescope slews for Gotos. 

I fitted a shelf to the eastern side of the pier for the laptop with room for a mouse pad. A vast improvement on any other arrangements I have tried so far. The mouse just seems completely effortless and natural compared to the laptop's own touch pad.

I have also ordered a cheap, plywood, rise and fall, swivel stool/chair with a back from IKEA. It was decided that castors were not ideal for the observatory situation. Pad type feet will stay put and only seat rotation is required to access the seat at the computer between visits to the eyepiece. The back of the seat is furnished with a loop at the top to allow easy movement. Or hanging?

It ticks every single box I might have wished for in an observatory chair. Even down to the wipe clean, plywood seat. No doubt a thin, loose cushion can be found for greater comfort. This can take a tour through the domestic laundry facilities at necessary intervals.

The observatory continues to show a 4°F differential between inside and out. This is regardless of sunshine or time of day or night. The outdoor sensor is placed in free air under the veranda to avoid any sunshine affecting the readings. The thermometer case houses the indoor sensor and is sited to avoid direct sunshine.

I got rid of the heavy stepladder which greatly increased the sense of space in the observatory.

The laptop continues to enjoy excellent wireless reception in the observatory from the indoor router. 

I should have my red LED lights in the post tomorrow. I have no real idea what to expect but hope for a low visual impact when they are lit. The dark adapted eye needs only a little extra help to avoid the observatory's pitfalls.

NOTE: My ASCOM drive problem were solved with the new download of ASCOM Platform 6.41[?] I remembered that a previous platform download 6.31 [?] fixed my dysfunctional Goto problem last time. So I checked and found the latest download for my laptop.

As soon as I tried a Goto slew ion the laptop the stepper motors started up. Whoopee! Only to find the tube was still badly balanced after adjusting for the binoviewer and its two LP eyepieces. Whoops! 😳

Ideally, I need to find some hand knobs for the wormwheel clutches to allow quicker shaft freedom for accurate balancing. Then I can quickly confirm the two, sliding weight, balance positions: With and without the binoviewer.

With all three balance weights now in the fully forward position I can safely move the tube up through the rings. I hope to gain some freedom at the tail end. At present I cannot even use a straight through eyepiece but must use a 2" star diagonal. I had imagined I'd have much more room in a ten foot [3m] dome!

I'm an absolute martyr to GEM mounting offset! I can feel a rebuild into an inverted fork, equatorial mount coming on soon!

BTW: There is a new ASCOM Help forum for users. No longer on Yahoo.

https://ascomtalk.groups.io/g/Help

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Observatory: Going live: Lessons learned:

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Saturday: 32F. A clear night with Saturn sinking out of sight to the SW and Mars keen to follow. The Moon was still a bright glow rising in the East.

First frost as the clocks go back after a first attempt to use the observatory. Early sunshine replaces a late moon. 

I started up the laptop and AWR, Stellarium and even downloaded a new version of Stellarium Scope to see if that helped. It is so long since I used this equipment and software that I had completely forgotten the basics.

The telescope was accepted by Stellarium and was "Started" but Ctrl 1 had no slewing effect. Neither the cursor was identified nor was the blue LED on the FTD cable showing any sign of life. I think there may be a problem with my laptop having only USB3 ports. I had an error message in Windows when I checked the com port 3 fitted with the cable. Checked again and "the device is recognized and working properly."

So I manually slewed to Mars and tried a few eyepieces. Mars was colourful but not remotely clear.
Fighting the resistance of the wormwheel clutches made it very difficult to point the telescope! 

By then it was 8pm and dinner time. So I switched everything off and returned indoors. After doing some quick checking online I realised that I hadn't been offered a choice of telescope in ASCOM. More after dinner.

A couple of hours later I was still trying to get Stellarium to show that ASCOM was present. I am presuming that the telescope choice I had made was Stellarium's own plug-in and nothing whatever to do with ASCOM.

A few of the lessons learned:

I need to get the software working properly in daylight.

The computer/laptop needs a proper shelf and a proper seat to use it with a proper mouse on a proper mouse matt. I hate the touch pad on the laptop even though I use it most days. I'm just more of a mouse man.

A bright torch is an incredibly poor light source in a dark observatory.

The tailpiece of the 7" is much too close to the edge of the dome and the 2" star diagonal contacts the steering wheel brackets in some places. The brackets should have been cut off long before now but I feared a need for some change along the way. The brackets have to come off individually and be firmly held while I angle grind off the excess then smooth off the cuts to avoid injury. 

I need proper locking knobs on all the sliding, tube balance weights. Hex keys are a total pest in the dark!

I need to fit a proper finder on the 7" in two, proper, 3-point, stand-off rings. NOT the stupid CR150HD focuser shoe with the single sprung alignment pin. It can't cope with the diameter of the 8" tube.

A normal stepladder is far too big and clumsy for a modestly sized observatory housing a 7" refractor. The highest I need to be is at eye level with the Dec shaft when it is horizontal. Both stepladders will have to go.

There is far too much ventilation around the dome skirt. I need to fill in the octagon flats with arcs of plywood to make a full circle to help to reduce the draughts. Though the dome is 16 sided this is still much nearer to a circle than an octagon.

I need proper shelves and covered storage for everyday observatory stuff like eyepieces, extension tubes, Barlows and diagonals. Rummaging through plastic storage tubs on the floor is absolutely hopeless and damaging to the accessories.

The 7" refractor needs to be perfectly collimated in daylight. I have to use a "long series" hex driver on an extension bar just to reach the collimation screws in the bottom of the fixed dewshield. I should add tubular[?] extensions to the screw heads to allow effortless finger adjustment.

I need to know the precise position of the tube balance weights on the 7" when I'm fitting the binoviewer. The Moon was huge [and rather soft] with the binoviewer's default 2.8x GPC [glass path corrector] even with 26mm EPs. Very little chromatic aberration visible even on the limb. The Binoviewer image looks promising but needs much more work to be used properly.

Have everything I need up in the dome before I start. Not down in the shed nor upstairs indoors! I need to print a list and have a standard routine. Though a bit of practice will help enormously. I had lots of stuff stored elsewhere while working on the [year long] dome build. Much of it had not been touched for what seems like ages.

The IH2 [Intelligent Handset AWR drive control paddle] and its horribly stiff cable needs to be fully mobile. I had fixed it to the north side of the pier thinking that would be best. That meant I could not center objects from the EP in the absence of computer control. The four different speed, AWR drives are excellent in practice but need the handset at the eyepiece. There are several tracking speeds as well all available from the handset.

What I did like: The space available when the big stepladders have gone.

The trapdoor was okay to walk on when closed but without any light I was constantly terrified of falling through the usual big hole in the floor. It was far too heavy and too much trouble to repeatedly open and close the hatch while I was working on the dome. So I left it latched up for most of the time. Plans to have trapdoor counterweights on cables have not been applied yet and may not even be practical.

Without the building ladders dragging on the rubber skirt the dome was acceptably manageable in rotation. Practice will aim the slit more accurately at bright objects. This is not as easy as it sounds due to the considerable offset of the telescope on its mounting.

As I struggled with pointing the big 7" refractor OTA I was wishing I had the folded OTA on the mounting. Inside the dome it would not be subject to the optics dewing as it is outside. It would solve all the problems of the dome being slightly too small for the "long version" of the 7". Moreover, the folded version would not lose collimation when left permanently on the mounting. I was removing the objective every time when I was observing outside.

Yes the big scope is impressive and traditional and it just clears the dome. But it is bulky and unwieldy in use. It's huge leverage makes overriding the wormwheel clutches all too easy. Changing an eyepiece or diagonal seriously changes the tube balance. The Goto drives insist on using computer slews only. Or they will lose their bearings on the sky. Since they work by counting the turns of the stepper motors.  It takes considerable patience to wait minutes for a long slew! When they actually work!

Click on any image for an enlargement.

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Observatory build: Some observations.

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Saturday: Did I ever tell the world that I hate the term "First Light?" It just sounds so.... presumptuous.

A domed observatory has a unique atmosphere. It has an air of melancholy and nostalgia reminiscent of forgotten ruins and abandoned buildings. One of those timeless, rarely visited places forgotten by man.

Clock rooms in old buildings and dusty church towers enjoy the same distinctive sense of an alien space. One, not remotely furnished for visitors but for housing the hidden needs of once vital machinery. Those which kept our cast iron, rusty pipe bends with flanges and toxically over-painted cables of yesteryear's technological world turning. Now it's all warm rooms and keyboards, rows of monitors and more cables than the untrained eye can easily take in. The back of a posh hi-fi stack writ foolishly large.

The past tense viewpoint is reinforced by the unique shape of the dome as seen from the inside. Its soaring struts and unique and obviously, wooden character smacks of bygone times. There are no sharp corners or straight lines to drag the eye down to the commonplace, virtual reality of commercial propaganda. Its jarring cosplay characters and universally overdone, special effects.

The heavy metal of the mounting is reinforced by the telescopes themselves. Which stretch monumentally into the unlikely, upper reaches of the dome. As if longing for escape from the egg, the chrysalis, or the missile solo on receipt of an antique signal. There is a strong sense of being completely alone in a unique and strangely privileged environment. Or, none of these things and I just have a very vivid imagination.  

I now need a drop-down[?] shelf for the vital laptop. Ink stained, mahogany boxes of gold lacquered brass, RAS-threaded eyepieces are now so yesterday. A computer shelf must now be placed at normal seated height on the northern side of the pier. It will need a decent light shroud for solar imaging.

Avoiding this shelf, while moving around the observatory, will become a new priority. Suggesting it be made with a curved form to avoid painful collisions in the dark. Though I'm hoping the low level, red, LED lighting will make life easier. I just pray it doesn't become like Santa's Grotto. The saturated sugar and dash of spice of eternally infantile, Disneyland pastiche. That would be truly awful!

A more suitable chair, than my present, folding beech example might be found in a charity/thrift shop. The beech chair takes up a lot of room, is noisy when moved and does not slide well on wooden boards. Which, potentially, makes passing by the newly vital, "computer shelf" an even greater obstacle.

A low, adjustable height, round based, 'bar' stool might be preferable. A vinyl top will avoid dampness and can easily be wiped dry if needed. One with a white top would be best. Again for avoidance in the dark. Or when blinded by the sudden inrush of light on opening the shutter doors on glaring sunshine.

Click on any image for an enlargement.

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Observatory build: Lights and drives:

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Friday: I have ordered a long string of 100, low voltage, red LEDs and a couple of red E27 LED bulbs with low Wattages. The band type LEDs are cosmetically neater [and brighter] but I want to hide the LEDs out of direct line of sight under the octagon's surrounding woodwork. Unless the LEDs are particularly dim and then it won't matter.

The "Xmas tree" style wiring provides much greater flexibility in siting. The small 230V LED bulbs can be stealthily deployed 'downstairs' to light the way to the observatory stepladder without blinding me.

I built a temporary 'Xmas tree' of AWR[Technology]UK Goto drive boxes on the southern side of the pier. The cooling fans of the AWR resistance box are so noisy and irritating I wanted to put some some distance between us. I have clipped the cables onto the temporary, plywood, pier cladding to avoid tripwires.

The 18mm plywood was supposed to be BWP flooring grade but immediately became wavy in damp weather. One day I shall get around to replacing it. Though it is strictly a cosmetic issue rather than structural. So I could slit the raised waves and glue them back down before painting the pier for a smarter look.

Having the drive electronics working allowed me to check the telescope balance and stepper motor drives. The motors are sounding rather rough after being under cover for many months. These motors stall [very noisily] if they meet any resistance. Though usually, only in Slew mode. Of course Gotos are also carried out at Slew speeds so stalls are to be avoided.

I have turned some shorter, tubular brass, counterweight spacers to re-balance the telescopes on the mounting. The three 5kg weights are a smidgen too heavy. So that sometimes the drives have to work "uphill."

I added a second tube balance rail. This time on the 7" OTA. Slacking off the clutches on the wormwheels proved that my earlier imitation of balance was rather far fetched. Once completely free of friction I was easily able to balance the telescopes and Polar Axis properly.

Once close to balance I find it most beneficial to give the telescope a larger push than strictly needed. Just to see if it continues to travel further in one direction than the other. Following careful balancing the occasional noisy stalling on Slew then ceased.

Stripped of the outside ladders the observatory can finally be seen in all its glory nakedness for the first time. A day of rapidly changing weather. Showers one second and just as brief sunshine the next. The 7" refractor's dewshield cap can be seen peering out of the temporarily open, observation slit. The more modest 6" is snuggled just above.

Thanks to IKEA for their all stainless steel clothes rails. Though the latest model is a flimsy thing compared with the sturdy original. The later examples being smaller in diameter, with tiny support bracket and tiny screws in each end. This makes them sit far too close to most surfaces to function as a towel rail, or whatever.

I deliberately placed the new balance rail on the opposite side of the OTA to the 6" refractor to reduce torsional imbalances. Thought the 6" is much heavier than my paltry, tube balance weights, of course, it may still help the dynamic balance.

Click on any image for an enlargement.

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Dome build: Settling in?

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There is definitely a learning curve to actually owning an observatory. It is only now sinking in that I have an observatory instead of a seemingly endless, building project. This requires a complete change of attitude on my part. What can I do with it now it exists?

When the sky darkens for rain I can instantly close the shutter doors and relax. No more panic stations to get everything safely sheltered before it is wet through and completely ruined or starts to rust. When the sun comes out it can be blinding nuisance while working on the instruments. Now I can just rotate the dome to provide much more even and comfortable light. Even half close a shutter to reduce the light infall.

Likewise with the wind. If it picks up I can easily rotate the slit downwind. None of these options exist with a roll-off roof observatory. Except for closing the roof for shelter. Which is only a two second job on a dome. Or a delay on a motor-driven, roll-off roof.

The sky was clear but very misty tonight. [If that makes any sense.] So I was able to sight along the OTA on the Pole Star for a quick and dirty confirmation of N-S alignment. Pretty close! Polar altitude was checked earlier with a clinometer. I have no eyepieces or star diagonals fitted yet so there was no chance of greater precision. I'll wait for a clearer night or do some "drifting."

The exercise certainly "shone a light" on my desperate need for lighting in the dome and the lower building. Climbing the steep aluminium stairs, with one hand clutching a torch and the camera case in the other, is not the easiest of tasks. This, despite my hundreds of ascents and descents in all conditions while carrying heavy loads of tools, umpteen ladders and a succession of huge and heavy materials.

A headlamp? From direct experience I find headlamps uncomfortable whatever the headgear worn underneath. I have a powerful, rechargeable, Klee LED headlamp. But cannot tolerate the lamp body weighing down, like half a building brick, on my forehead. Let alone its hefty battery pack and its ridiculously stiff connecting lead. Can you imagine the head injuries if one of these headlamps was worn by a mountain biker? One who somehow managed an unexpected AOT [arse-over-tit] alone in the darkness on an isolated forest track?

Click on any image for an enlargement.

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Observatory build: Mounting the 7" refractor Pt 2.

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Thursday: A dry, but windy day with sunny periods. I decided to take the dome stepladders down. This allowed me to swing the telescope [tube] freely. First I set the tube vertically on the bare tailpiece resting on the floor. Then clamped the top of the tube in the lower tube ring. This allowed me to fit the objective lens in its stumpy dewshield on top of the tube while working comfortably from a short stepladder. 

Next I added two 5kg counterweights to the end of the Dec shaft. During this step, the tail end of the tube was tied firmly to one leg of the pier to avoid the tube taking flight. The next stage was pushing the tube bodily up through the rings while pointing at the Pole. I could now safely pinch the tube rings to stop the tube sliding up or down.

This was followed by my fitting the focuser in its collimating and rotating tailpiece to the tube. It needed a small longitudinal adjustment of the OTA in the rings to lift the focuser to a better height. Before balancing with the tube weights on the cradle. Finally, I could clamp the tube firmly in the rings and the mounting was done.

I still need to collimate the optics of course.  Then decide on the best position to fit the 6" H-alpha, solar telescope. I don't think it would be sensible to mount the 6" directly outboard of the 7". This would considerably increase the moment [mass x distance from the pivot] and require many more balance weights.

A more sensible, side-by-side arrangement needs some stiff mounting bars to fit on the cradle. The moment rises but would be far more modest in proportion. Probably requiring only one extra 5kg counterweight over the two already required for the 7".

Or, I could use two 8" rings to mount the 6" beside the 7". This would save me having to make crossbars for the two instruments to sit on the cradle. The 6" can be adjusted to fit snugly beside the 7" simply by rotating the rings as appropriate.

In the end I fitted the 6" onto the side of the saddle in place of one tube balance rail and weights. I checked carefully and the 6" doesn't contact the mounting even in the 'weights up' horizontal setting.

The images show the telescopes pointing at the  zenith. On both the east and the west of the mounting. When it is to the west I could stand upright on the stepladder for a more comfortable viewing posture.

The 7" could still be lifted by another 6" and even more if the pier were not so far to the south in the dome. I placed the pier in the center of the dome. Which means the dewshield is much nearer the northern upper dome but clears the southern side by a good margin. This is the result of the northern offset of a GEM. [German Equatorial Mounting.]

I could overcome this problem by adding a new, very thick, plywood top plate with a supported overhang to the south. Only time will tell whether the offset becomes a noticeable nuisance.

The present situation certainly shifts a refractor eyepiece nearer the northern observatory wall. Which matters far more than a safe dewshield clearance up high. Lifting the tube through the rings reduces clearance at the top but progressively increases eyepiece clearance at lower pointing angles.

I'll take some daylight images of the big GEM to confirm the northern offset.

Next day: Such images merely confirmed that the offset lies in the area of 3-4". Worse, a check of the pier, relative to the octagon, proved an error of 7cm in a northerly direction. So moving the whole mounting towards the south would require a 6" movement to cancel both offsets.

Unfortunately the entire [huge] pier cannot be moved. Nor can it be tipped so far towards the south without serious woodwork changes. Which would throw the top plate well out of level anyway. 

The northerly offset is also the CofG offset from the center of the pier. So, in theory, the mounting and its heavy burden of instruments and counterweights is also offset to the north. Which, in a paranoid moment of pure pedantry, might suggest the pier is being pulled slightly northwards.

How to support the massive load while I replant the mounting base plate and 16mm central stud? I have no idea, but I'm certainly not risking lifting it by a couple of eye-bolts at the top of the dome!

Click on any image for an enlargement.

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Observatory build: Mounting the 7" refractor.

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With the brake/clamping sleeve now working I added the tube rings and bare 8" tube for the 7" refractor. No counterweights were needed for this. Though I checked and found there was ample room on the Dec. shaft for at least three weights, possibly four. 

The dirt cheap, cast iron, 5kg "Olympic" class 2" bore weights are 25" thick x 9" Ø. This was the maximum diameter I could swing in my lathe to tidy up the very roughly cast rims.

With the doubled, builder's stepladders still in place there was not much freedom to move the telescope tube around. There is only about 10" clearance above the cell supporting ring when the tube is vertical.

The slit would be open during observation so there would be more clearance provided care was taken. The dome certainly seems very much smaller with the telescope tube in place. Getting rid of the stepladders will help.

I need a larger knob on the PA brake to allow more torque without strain. I just happened to have a small hand-wheel on M8 studding so used it to test how well it worked. After endless searches using all sorts of terms I still haven't found a suitable knob/hand-wheel/stjernegreb/fingergreb/håndhjul/etc.etc.

There is the risk that a large wheel will overtax an M8 thread, of course. The cheapo tap and die set I bought recently is proving as useful as chocolate teapot. So I have been using the better quality taps bought individually in the UK from flea markets. The new taps cannot even start a thread and are only useful for cleaning an existing thread and then only with great care.

I am tempted to add a rotary bayonet fitting for the 7" objective as I did with the folded refractor. That needed a bayonet fitting objective because of the weight of the lens and having to rebuild and dismantle it, high on the mounting, every time I used it.

I even bought a wide set of sturdy aluminium steps for this specific job but never got around to fitting a suitable handrail to steady myself. Given the straight tube refractor will be permanently mounted I am just thinking of the initial ease of fitting the heavy lens to the long tube. A simultaneously awkward and delicate operation. Standing the tube on end makes it unstable and too tall to reach from the floor.

See the image alongside for a better sense of scale of a 7" f/12 refractor. The tube balance weights have since been moved to the cradle on the big mounting. Just to save having to lift them along with the OTA.

The alternative, in fitting the lens to the main tube first and then lifting the complete OTA into place is equally fraught! I use a spare tube ring to prevent the OTA sliding down through the clamping main rings, but still. It is a heavy and awkward lift.

I have tried pointing the cradle directly at the Pole. Or with the cradle horizontal or sloping. Nothing helps much with this weight, bulk and height. Such physical hurdles to mounting a delicate telescope quickly become psychological hurdles to do any observing. Which is what drove me to build an observatory and the folded refractor OTA before that.

The folded refractor was too prone to dewing of the mirror optics and I never completed a cloth shroud. It would have been too complicated to shield the folding mirrors with their own dewshields due to the odd reflecting angles. Too much shielding would have caused heavy vignetting. Too little would have made it all rather pointless.

A folded refractor OTA needs to be fully enclosed or in the shelter of an observatory. It was certainly no lighter than the 'normal' straight tube build. Quite unexpectedly it was far more difficult to put on the mounting due to it being considerably shorter than the straight tube. So that it could not be lifted like a Scottish caber. Hence the keyhole bayonet front plate for the objective mounting. Just another hurdle to overcome for those whose instrumental ambitions exceed their physical strength and agility.

A hefty eye-bolt, or two, at the top of the dome for my block and pulley might be useful. If I could trust it for the vital lift. I am loathe to hang the chain hoist up there due to its own considerable weight. Lifting the hoist needs its own hoist!

Click on any image for an enlargement.

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Mounting build: Counterweights and shaft locks.

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I should paint the weights white to help avoid collisions with my head in dim light. I might just have to get a longer length of 50mm stainless steel shaft to make more room for more counterweights. Fortunately it is very easy to swap shafts thanks to the Tollok clamping bushes. Apart from handling the sheer weight of the shaft itself, of course. They really are "lumpy!"

It may seem like excessive fuss over a few counterweights but I'm thinking of the future. Old age is eventually bound to take its toll. My ability to lift heavy weights to the height of the mounting is bound to reduce over time. Lifting a weight above head height requires a stepladder to lift me to my former head height.

Moreover, I never fitted shaft locks or brakes to the mounting. The clutches on the wormwheels are protective. Not intended to lock the shafts against severe imbalances. Loose weights on a bare shaft waiting for the locking ring, could easily cause it to tip downwards. With catastrophic results. The damage to the floor and ladder from three 5kg steel disks falling from such a height would not be light. This assumes they miss me as I teeter high on the ladder.

I once tried using a slot in the end of a length of timber to support the shaft while I loaded the counterweights. Though this is not completely safe unless the timber prop is securely located and the bottom resting on a firm surface. Not to mention the prop being of exactly the correct length/height.

What happens when the weights want to be in the same place as the timber prop? When there is no more room for more weights and the locking collar? With such large and heavy weights [and heavy instruments ] it doesn't take much of an imbalance. The whole assembly can rotate viciously when released. I could screw a sturdy metal plate with the slot to the prop instead of having 2" thick timber using up vital shaft space. 

If I let the weights swing downwards I can't reach the raised cradle with the large and heavy telescope!

So I really need secure shaft locks. Not simple screwed rods pressing onto the shafts. That would mar the shafts and make shaft removal through vital components impossible.

Ideally it needs really solid, split block clamps to provide enough pressure from comfortable hand wheels working on ample diameters of stainless steel screwed rod/studding. The split blocks need to be securely located against all rotational movement and a close fit on the shafts.

Excessive precision requirements should be designed out first. While still making the clamps completely fail-safe in use. And, without requiring excessive hand pressure on the hand-wheels. That means ample leverage on the splits by moving the actuating studs well away from the shafts.

The contact/braking/locking surfaces of the clamps must be able to be spun in the lathe. For accuracy in hole sizing and position. A cylindrical furniture 'nut' sitting in a cross drilled hole will avoid deep thread cutting for the actuating stud.

A much simpler idea would be a half circle clamp hinged on a fixed bolt. The bolt becomes the only necessary location point for the clamp. A cylindrical nut in a cross-drilled hole avoids making deep threads in the clamp body which would always be subject to side forces.

The entire clamp can be lost inside the bearing housings. With only the hand-wheel visible on the outside.

Two strips of aluminium could be used with a small separation between them for the tension stud. This would allow the hinge bolt to become an eye bolt sitting between the two strips. The eye bolt would only be subject to compression forces.

A 50mm hole saw can be used to make the half circles. Perhaps clamping two sets of strips together to provide a symmetrical and simultaneous drilling operation.  The eye bolt can be planted once the half circle of the clamping strips are closely located around the shaft. Thereby avoiding the need for high precision in their location. Even asymmetrical pressure over the area of [half of] a 50mm shaft should be enough to hold it absolutely firm.

There was s little room inside the polar bearing housing I decided to go for something even simpler. I bored a cylinder of brass to make a close fitting sleeve for the polar shaft. Then threaded the top plate M8 for a small hand-wheel. The end of the hand-wheel stud was reduced to fit a 6mm hole in the brass sleeve. The hope is that the brass sleeve will provide a lock without the hand-wheel stud coming into direct contact with the shaft. If the threaded rod on the hand-wheel tries to bend sideways I shall have to provide a supporting plate inside the polar bearing housing. Just to stop lateral movement.

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Dome build: First rain test and equipment musings.

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Tuesday: Went out to check the dome paint's waterproofing qualities after a night of rain. I am delighted to report only two small dark patches high up. I'll record their position and check the area outside when it stops raining. Given the small quantity of leakage a second coat of paint might just seal it. The other dark stains are previous leaks when the dome was unsealed and unpainted.

I needed a torch to see anything in the dome. It really is very dark in there. The rain continues. So I will monitor for further leakage as the day goes on. At least it wasn't dripping anywhere. The rubber skirt is doing its job with no sign of leakage onto the top octagon ring. Though I do need to make some water bars for the bottoms of the veranda doors. The strong wind had blown rain in under them.

It may seem odd to some of my readers but I really haven't given much thought to using the observatory. The mounting has been safely covered for months as I beavered away providing its shelter. I have watched the Sun, Moon and planets crossing the sky without being able to point a telescope at them.

First I have to rebuild and fit the 7" f/12 refractor onto the big mounting to check its clearance from the dome. That will set how long a dewshield I can fit without a collision with the woodwork.

I'd like the 6" H-a refractor fixed alongside the 7" for viewing the solar prominences. That means balancing the extra weight of two instruments. I'm still not sure how many 5kg 9" Ø weights I can fix on the Declination shaft. There is a brass spacer I fitted to push the weights out as far as possible. With only the three locking screw collar clinging to the end of the shaft.

The 6" needs only a single weight. So I might just get away with three counterweights or 15kg for the pair of telescopes together. It depends whether the Dec worm housing is going to prove a nuisance. It could be rotated by 90° but then, it may not clear the wormwheel rim.

Which reminds me that I should paint the weights white to help avoid collisions with my head in dim light. I might just have to get a longer length of 50mm stainless steel shaft to make room for more counterweights. Fortunately it is very easy to swap shafts thanks to the Tollok clamping bushes. Apart from handling the sheer weight of the shaft itself, of course. They really are "lumpy!"

It may seem like excessive fuss over a few counterweights but I'm thinking of the future. As old age takes its toll my ability to lift heavy weights to the height of the mounting is bound to reduce. Lifting a weight above head height requires a stepladder. Moreover, I never fitted shaft locks or brakes to the mounting. The clutches on the wormwheels are protective. Not intended to lock the shafts against severe imbalances. Loose weights on a bare shaft waiting, for the locking ring, could easily cause it to tip downwards with catastrophic results. The damage to the floor and ladder from 15kg steel disks falling from such a height would not be light. This assumes they miss me as I teeter high on the ladder.

I tried using a slot in the end of a length of timber to support the shaft while I loaded the counterweights. Though this is not completely safe unless the timber prop is securely located and the bottom resting on a firm surface.

Click on any image for an enlargement.

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Observatory build: Wooden handrails for the veranda.

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As the observatory nears completion the straight line of vital progress begins to branch into many minor jobs.

Before I woke up fully I found myself rehearsing a wooden handrail to go around the veranda fence. The remaining lengths of larch flooring could be ripped in half and then grooved underneath to fit snugly over the top of the fence. This would provide much greater stiffness than merely letting it sit on top with a few screws holding it in place.

The devil is in the detail. The corner posts do not readily lend themselves to a direct connection between the straight lengths of wooden handrail. The entire fence also needs to be lifted slightly. So that it does not continue to rest on the veranda floor. This will help to avoid rust forming where dampness is likely to remain.

The tubular steel fence posts can then be bolted to the main structure for even greater rigidity. At present they merely pass through tight holes cut in the "corners" of the veranda flooring. Even so, the octagon geometry greatly favours the fencing. Any outward pressure on one panel tries to pull the next two inwards. The fence has provided a greatly improved sense of security when moving around on the veranda to work on the dome. It deserves to be properly finished off with an attractive handrail.

I should probably oil the larch flooring to extend its life. It has already had a "mineral" treatment which turned it dark grey. There is no obvious sign of rot or decay. However, being fully exposed may require a more waterproof finish to shed the rain more quickly.

Which reminds me: I should make new rubber flashings for the base of the obs. walls to replace the stiff and narrower plastic strip. This will help to throw run-off outside the lower, octagon walls. Though there has been little sign of ingress so far and the ground floor gravel remains satisfactorily dry.

My wife and I had another discussion on painting the octagon building. With the dome now painted dull green the supporting building has safely retired into the background. With a fairly even, oak-like appearance from the "Safe-Way" mineral treatment. There is no great hurry to paint it so I'll see how it looks and how we feel about it after the winter.

The grooved, plywood boarding I have used to clad the building has shown remarkable resilience. Even after 15 years of weathering on the shed next door without any surface treatment at all. The natural, dull grey-brown of the plywood surface seems to suit the semi-wooded, rural situation. Painting it would only draw attention to it now and require repeated re-painting into the future.

The aged look gives the buildings a sense of permanence which I rather like. It is, after all, a matter of personal taste. One, over which, I thankfully, retain control. I enjoy the slightly melancholy appearance. As if the buildings had just been discovered after languishing somewhere untouched by time or vandalism. Old buildings should never be tarted up by New Money. Let them tart up a modern building and leave the gently aging for those who still enjoy them as they are.

You couldn't make it up! There was short, sharp shower before normal sunshine and clear blue sky returned. I had power tools and power saws outside. Along with a stack of larch boards from which I was selecting the clearest [of knots] for the handrails. Everything had to go back under cover before it was soaked. Grr! After that I had to drag everything back out to continue rounding over the shoulders and sawing slots. The little Makita router is a revelation compared with the full sized machines. I have used the Makita for all sorts of jobs since I bought it. One handed working even at arm's length is very easy.

I discovered the fences can only be lifted as one unit. The position of the three clamps on the tubular posts means the fencing is locked into one position on the posts. I wish I'd noticed this before I brought out a ladder and went round loosening every clamping screw! Only to have to re-tighten them all over again. Am I having fun yet?

The one handrail I dropped into position looks a bit insignificant from my computer window. Hopefully a "full set" will look rather more imposing.

The rain strip might dry out again in the sunshine. It was wet from overnight rain this morning. Then it rained again just as I was going to take a break from the woodwork to paint it. Nevertheless, I did manage to paint the rain strip in the mid-afternoon.

I also made four out of seven handrails and fixed them with three bolts each. First I ripped the larch planks into two halves on the table saw. Then rounded all four corners and deeply grooved the undersides to fit the fence tightly. Then cut them to exact length with different miters at each end. Finally they were centrally drilled including down between the two top wires of the fence. Before finally being screwed down firmly onto the top of the fence.

I ought to get some stainless steel screws for this job. The zinc flashed screws will rust very quickly. As expected, the U-formed, wooden handrails increased the stiffness of the fence quite dramatically. The front rail is visible in the image above just behind the ladders and a further two on the left.

The dome is now pointed towards the west where tomorrow's storm is supposed to come from. Gusts to over 40mph are forecast with 12 hours of rain. This will be a good test of the dome's waterproofing! A second coat of paint is suggested by Gori but that will have to wait for another fine day.

It's a shame those who patiently followed my build on Cloudy Nights forum can't see my latest progress. The moderators were blinded by my insubordination regarding my mentioning affordable, large aperture, solar, H-alpha telescopes.
   

Click on any image for an enlargement.

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Dome build: Shutter rain strip.

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Sunday: It is getting light and the dome is still green. And still defying the camera to see it as it is with the naked eye. The camera captures only the reflection of the sky. Leading to a pale, washed-out rendering unless I drop the gamma.

I am quite pleased at how well the facets are showing. A "broken" surface was always preferable to a smooth curve. It sounds very odd,  but I actually dislike the green version of a popular, commercial GRP dome. It is just too "grass green" and glossy for my own tastes.

Whereas my choice of low sheen, dark sage green just works perfectly for me. It safely makes the dome become almost invisible against the background trees. Unless you were actively searching for it with binoculars from the road, of course.

Today I need to prepare for the forecast rain and high winds coming in a couple of days. I need to add a rain strip to one of the shutters. Unfortunately their levels ended up being reversed between top and bottom sets. The lower half provides adequate clearance one way. While the upper favours the opposite way.

I shall have to lift the top of one shutter very slightly. Just to ensure the rain shield clears the other side as the shutters come together.

According to advisers on the forums, nothing more than a 2" overlap is required to keep rain out of a dome. If the edges of the shutters and the rain strip should collide it would be a disaster. Not only for the potential damage. But because it would be so difficult to reach the problem area in a hurry.

I could have glued the rain strip on but decided to make it independent. Just in case it needed modification in the light of experience. If the dome should sag over time it would be a serious struggle to reach the rain strip without a hoist. A few screws can usually be undone. Breaking a glue joint and making good again would be major work at that height.

The image above shows the unpainted, 4mm birch plywood, rain strip in place.  I lifted the top, right side, drawer slide slightly, re-fixed it and that was it. The shutters came together parallel to each other and without a collision. Tipping the draw slides controls the way the shutters come together. I'll paint the rain strip as soon as possible.

 

Click on any image for an enlargement.

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Dome build: Green paint!

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I took the chance and bought the paint in anticipation of a sunny afternoon. It wasn't continuously sunny and it only reached about 52F but I was delighted to enjoy such favourable weather in mid to late October.

It took me a little over three hours to paint the entire dome including the shutters. There was a lot of stretching and climbing and descending and climbing back up. My arm, chest and back were aching too, but I was finally finished at about 5pm.

My wife caught me in the act early on in my pair of baggy old "painting" trousers with the waist elastic long gone. The blue shirt is my "artist's" shirt too and well daubed though I claim absolutely no skill in that direction. My scruffy outfit was rather too warm when the sun shone!

The gathered waist is caused by my safety "belt." Actually a scaffolder's safety sling with a carabiner joining both ends and linking to my safety line and scaffolder's hook attached to the top rung of the ladder. I found the weight and bulk of my full safety harness far too restrictive but needed something to save me from disaster should I slip. Or lose concentration while up high.

Gori 'Extreme' "wood protection" paint was my final choice with a claim of a 15 year lifetime. Whether I shall survive that long and still care, is anyone's guess. The paint has quite a nice, low sheen. Though I might still have preferred full matt.

It is proving very difficult to capture the true colour with the camera. I had to wait almost until dusk before it would stop reflecting the white, cloudy sky. See images below a more accurate idea of the colour as I see it. Dyrup claims it is "Smokey Sage" but that was a pale green in the mixing machines in three different builder's merchants.

The paint went a surprisingly long way, was easy to brush on, without drag, but tended to show final brush strokes. Probably the white primer underneath and the cheap 75mm [3"] brush I bought for the job. Only a cheap idiot, like me, would spend good money on paint and only a few quid [equivalent] on a brush. If I stroked from edge to edge the brush marks would disappear. I may also have been slightly too meager with the paintand overworked it with the brush.

As usual, I used a cheap 1liter, polythene, measuring jug, with moulded handle, for paint handling convenience. The hook shaped handle offers increased security when I'm working from the ladder and it is a perfect size for the 3" brush. The channel shaped handle can easily be trapped against the ladder while holding on with one hand. It also provides the perfect natural rest point for the handle of the paint brush.

It probably needs another coat but I am delighted to have the dome [hopefully] waterproof at last. Not to mention the "brilliant white" primer now being safely tamed. It could have been seen for miles if there was anywhere it could be seen from that distance. The view from the road is very restricted to a short stretch between houses and trees. I didn't want anybody falling off the road while rubber-necking a white dome.

I make a habit of photographing the observatory from the road on my morning walks and could not not wait to see an end to the glaring white. Highly visible against the dark background trees! The images are a handy reference for recording building progress over time. Though few others would really notice any difference.

Click on any image for an enlargement.

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Dome build: Ever onwards!

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Friday: Fitted U-shaped metal handles on the inside of the veranda doors to give me something to pull on. It was proving difficult to close the doors when it was windy. 

Then  I removed the upper covers on the shutter doors and sealed between the upper and lower covers. After which I screwed all along the edges of both shutters to ensure they remained firmly in place. It sounds easy until you have to do it at full stretch from a tall ladder. I used a combination of inside and outside ladders. 

My safety belt was clipped onto the ladders in case I tried to fly. Which I nearly did today while I was fitting the door handles. I was crouched against the open trapdoor when I shifted my weight and automatically grabbed the [vertical] hatch for balance. Fortunately the two sliding bolts held the hatch firmly, with a bang against the stepladder handrails. Otherwise I could have been hurled headfirst and backwards down the ladder!

I also tidied up inside the observatory and swept the upstairs floor. Small off-cuts of wood and plywood had been gathering dust along with odd, fallen screws and packing nails around the edges of the floor. 

I hung up a digital, inside/outside thermometer with an outdoor sensor on a lead. This will be useful to monitor temperatures within the dome. The inside reading will be compared with the remote sensor hanging free under the floor of the northern veranda where sunshine never falls. 

An overheated dome can cause warm air flow out of the observation slit leading to poor seeing. Domes, in general, have a poor reputation for this thermal agitation problem. Like looking over a garden bonfire at its worst.

A white finished dome helps reduce inside temperatures by reflecting solar warming. However, my plan is paint the dome a rather dark green to make it all but invisible against the background trees. How that colour heats up, in warm sunshine, on a plywood base is anyone's guess. Plywood has poor thermal conductance and low heat capacity. 

The dome is exceptionally well ventilated around the skirt unless I deliberately close the gaps. Opening the downstairs entrance doors may force a thermal "chimney effect" up through the open pier. This should quickly scour any warm air out of the dome. Any breeze from the southerly direction will accelerate heat loss. Quite a gale blows up through the pier when wind conditions are suitable. Opening the veranda doors on the westward side will help further.

The dome is primarily to allow the telescope[s] to be permanently set up on the mounting without the need for constant re-alignment. The dome provides a weather canopy without much increased warmth. It also reduces thermal radiation to the cold night sky. So the observer remains slightly warmer and more comfortable without the normal wind chill of being fully exposed.  The slightest breeze drags body heat out of the observer and chills their extremities. Hopefully the dome will also end the problem of dewing of the optics.

I also need a clock which can be easily read in the dark without needing to find a torch. A wrist watch is a nuisance at night. Particularly when wearing a down jacket with elasticated cuffs and similar gloves.

The AWR Goto handset [paddle] provides an illuminated, digital reading of the time. Though I would need reading glasses to be able to make any sense of the figures. The same goes for the Goto controlling laptop of course. I only need +1 diopter at normal range to read screen text and to see the cursor on a planetarium star map. 

A string of red diodes on a long strip will hopefully be fixed around the dome. These would provide only a gentle wash of light to avoid crashing into things in the dark. The heavy counterweight on a GEN is always a head magnet. Red light will help to avoid spoiling my night vision.

A "downstairs" light will be vital to remind me to close the trapdoor to avoid falling through the hole in the observatory floor. I had planned a micro-switch on the hatch but that would risk failure to light up when the hatch is open and still lethally dangerous. A fixed downstairs light will provide the safety warning without any risk of unnoticed malfunction.

The big stepladder was deliberately placed inside the building despite all the obvious "pitfalls." An outside ladder would soon accumulate ice and snow. Which would be even more dangerous than man traps! Provided I clean my feet of snow before I climb, the ridged, aluminium treads should provide safety and adhesion. So now I need a doormat inside the building.I still haven't decided how to cover the ground floor. Slabs seem obvious while the present pea gravel shifts about a bit in foot trafficked areas.

I am sorely tempted to go and buy the green, dome paint tomorrow. The risk of being caught in midwinter without the ability to paint for many months ahead is a bit of a worry. If I don't paint the dome then I risk the wooden dome structure becoming saturated. With no chance to dry out until a warm, spring day arrives much later. The problem is finding a suitable weather window to ensure the paint goes onto a completely dry base.

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Hale bullied off CloudyNights for mentioning his solar telescopes!

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No, I am not George Ellery Hale, but I was bullied into leaving CloudyNights by the CN staff for Hale's own crimes against humanity.  Well only CN member's limited human rights, actually, but you get the point.

Did you know that every word and image you commit to CN becomes their property? You have no further rights once you hit the Post button. I didn't know this until I was told I couldn't expect my own creativity and contributions to CN to be removed.

My supposed crime [against CN] was mentioning "home made" or "modified" solar telescopes in a response to another member's query. Though I did add the explicit warning that CN did not condone such discussion. This warning was then thrown back into my own teeth as if it confirmed my own guilt. I have never read the CN rules and do not even know how, or where, to find them.

My own feeling is that "home made" solar instruments can, when correctly built, safely provide very high quality images of solar activity. More importantly they bring Hydrogen alpha imagery to the non-wealthy amateur without needing to take out a second mortgage.  Though it is not without some cost for the vital parts. Some skill at building telescopes is also assumed. There are experts who will construct such a telescope for you in 4"-6" aperture. It will not be cheap but you certainly won't need a second mortgage.

Information for building solar telescopes is readily available online. Many blogs, websites and [at least] two popular forums discuss the subject in minute detail. They relish building "alternative" solar telescopes. Particularly in larger sizes. Affordable "alternatives" to the very costly commercial offerings. Anyone can check the prices online but expect to shell out $5k for anything approaching 4" or 100mm for a commercial offering.  If you have to ask the price of larger apertures then you probably can't afford them.

Yet manufacturers of the highest quality and world wide reputation offer suitable solar filters for safely constructing these larger instruments.. These are vital for reducing the extremely dangerous levels of heat, IR and UV from The Sun's focused image. Search for Baader D-ERF to get a taste for likely costs. Then add a secondhand refractor to do the heavy lifting. 4-6" apertures are popular with amateur builders. An f/10 focal ratio is best if you intend to use a PST or its [internal] donor parts.

You'll need the [secondhand] PST to do the H-alpha magic. H-a is a deep red which the eye can still see clearly but provides unique views of the Sun's surface texture and prominence in breathtaking detail. A suitable camera or cheap webcam will capture most of that detail. The PST's internal prism is a known alignment problems.

As is the clouding of the PST's objective and internal filters. They fixed the objective coating problem early on but the internal filters are well known for clouding over. Fortunately the vital H-alpha etalon seems free of serious problems. Though, even here, quality varies widely.

You could, like me, buy a secondhand PST only to find it needed further expense to replace the damaged filter. In fact the same filter is such a well known problem that at least two independent companies manufacture direct replacements! The problem is getting the PST components apart. They were clumsily thread locked by the unskilled labour when manufacture was farmed out to developing countries by the US label.

CN's denial of information on building solar instruments is futile and utterly pointless in the Internet Age. To me, this smacks of protection of the foolishly costly commercial telescopes. Many of which are smaller than popular spotting telescopes yet cost thousands of dollars, Euros or pounds.

Some of these same, costly instruments have severe internal foibles requiring replacement of their own vital components for adequate safety or function. Or their internal filters cloud over, Making observation impossible without their removal and replacement. At huge, further cost!

CloudyNights does not allow any public discussion of the subject of DIY solar. They even suggested  I alter my own blog to remove all mention of my solar telescope building!  I found this demand completely unacceptable in a free society. The threat was then made that my wide ranging, telescope making blog signature would be removed. And subsequently was when I refused to subordinate to their demands.

If I refused to comply I could even have my right to post on CN completely blocked. Ironic considering my 61 page thread on my observatory build breaks all previous records. Perhaps my thread was hampering sales of APOs? [Apochromatic telescopes.] Over which so many members seem to drool like babies. Even when these same Apos are too small to be safely drooled over except by very early astronomical pioneers. [Like Galileo!] They are often a bit like commercial solar telescopes in stature but still greatly admired. Check the numbers of viewings of threads and posts on CN if you don't believe me. The more it costs the more views a subject gets.

No doubt those who openly discuss solar telescope building [elsewhere] and H-a in particular must wonder as to the real reason for CN's reluctance to discuss this subject. The CN emphasis is on safety.

Information provides safety in the absence of ignorance. We are not subject to the arbitrary rules of multibillionaire Chinese [or Russian] despots. At least, not yet. Nor are we still subject to the whims of an utterly corrupt pope and their Inquisition sociopaths. Perhaps CN should revert to the use of Latin to ensure they maintain full control via their own, constantly genuflecting, Thought Police?

The very small risk of injury or blindness due to incorrect construction of specialist instruments must surely pale into absolute insignificance in comparison with many other risks? Any child could so easily turn their plastic, "ant burning" magnifying glass upwards with catastrophic results.  

Any telescope exposed to sunlight is a solar magnet for the unwary. Even the humble "finder" telescope is a huge risk when the telescope is pointing at The Sun. How many of those who use a CN-approved solar filter in front of the main telescope remember to remove their carefully adjusted finder? Or fail to cap it securely when left in place to avoid realignment?

Don't even get me started on the dangers of Herschel prisms. Which often release completely unfiltered, focused solar beam from their exquisitely expensive, jewel-like bums! Often down at the perfect eye level for any passing child or toddler! Safety? What absolute crap! But you can still brag about your latest [expensive] acquisition on fully safety conscious, CN!

CloudyNights is a form of online club. As such, it can make up any rules it pleases. Though only for those who choose to be members. Even down to their making rules which ensure absolute ignorance of an increasingly popular branch of solar observation and imaging. One usually reserved for the wealthy in any size over a couple of inches aperture.

Unless, that is, the would-be solar observer chooses to ignore CN's total ban on the subject. To search elsewhere for information and build their own safe, high quality, large aperture, solar H-a telescopes. Again using widely available information online and the highest quality parts and filters. It's a well worn path by now and it's not as if you'll be tagged by the NSA for Googling "bomb making instructions."

Is it not hypocritical to allow discussion of commercial, solar "Herschel" prisms and full aperture filters? Both of which could either fall off if badly adjusted. Or even be blown off the telescope by the wind?

Just, for God's sake, don't ever mention "spectrohelioscopes" on CN! Or your cosy, CN world will coming crashing down around your ears! As you wait in terror for the Men in Black Suits to come for you in the middle of the night. But only on Cloudy Nights, of course. 😉

Hale Solar Laboratory - Wikipedia

George Ellery Hale - Wikipedia

George Ellery Hale (1868–1938) | High Altitude Observatory

 A Pioneering Astrophysicist's Private Observatory Hidden in a Pasadena Backyard - Curbed LA

Mount Wilson Observatory | George Ellery Hale   

National Park Service: Astronomy and Astrophysics (Hale Solar Laboratory)


It hardly seems worth mentioning but I am now banned from CloudyNights forums.
Just remember not to mention Herschel solar wedge prisms in front of the children and you should be okay.

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