3.10.2025 APO focal plane and Lunt 60MT H-a etalon positioning.

 ~*~

  After lunch I set up the bare Tecnosky OTA on the long [Losmandy] Prima Luce dovetail bar. Then mounted the telescope on the ZWO AM5N on the AVX tripod. With the telescope tracking the sun I was able to make repeated measurements to the sun's sharpest image as accurately as possible.

 I wanted to know the distance from the focal plane to some fixed reference point on the telescope. I chose the tip of the retracted dewshield as my reference point. 

 Mock-up of the position of the Lunt etalon. Relative to the 102mm APO telescope. Primary focuser removed.

 After repeated measurements I decided the sun's image was sharpest at 735mm. With the focal length stated as 714mm this placed the objective 21mm behind the forward edge of the retracted dewshield. 

 The rear of the Feather Touch focuser's rotation ring is 460mm from the front of the retracted dewshield. This second reference point would be 439mm from the objective. 460 - 21mm. It was this ring which would support the tubular adapter I intended to turn on the lathe. 

 The FT focuser body would be removed entirely. Leaving the distance to the Lunt etalon to be determined by the 264mm from focus rule. To match Lunt's own measurements in the 60MT. The Lunt etalon will also be supported on three, radial, pointed screws in a circumferential, dovetail groove. Just like the FT focuser.

 714 - 439 = 275mm. So the etalon must be supported at 275 - 264mm = 11mm behind the FT rotation ring. The tubular adapter will be approximately 85mm long. To reach to the front face of the Lunt etalon housing.     

 If I can find, or make, a supporting ring for the 76mm Ø, Lunt etalon housing. Then this would allow fine tuning of the etalon position relative to the focal plane. The exact, linear position of the etalon, relative to the focal plane, is important for the best possible H-alpha image. It is this position which sends parallel light through the etalon. Which also needs to be concentric of course.  

A simple, rubber lined, pipe clamp [or two] can be used to hold the Lunt etalon for tuning trials. The etalon will be attached to the Lunt focuser. Making for a rather weighty assembly. So stiffness in support is vital. A pair of clamps in tandem can be bolted to the dovetail bar. Which has useful slots for linear adjustment.

 If the pipe clamps are successful. Then a simple, bored disk of marine plywood can be clamped in the FT rotation adapter. Using the pointed dovetail screws for clamping. This will provide perfect concentricity and support. For the 52mm nosepiece of the etalon. While simultaneously allowing for sliding, linear adjustment. 

 Here is an image of the two 76mm pipe clamps in place. Attached to the Lunt etalon housing. They are quite smart and don't look too out of place in this context. 

 These clamps are usually fixed to the supporting wall with M10/M8 bolts. Which is much larger than the M6 standard of the dovetail bar. I may saw off the attachment bosses. To allow an M6 countersunk head screw. To allow an M6 fixing through a spacer. 

 Or, the rubber sleeve can be lifted. To allow M6 CSK screws to pass right through the bosses from the inside of the clamping ring. This will leave the bosses to provide very firm support. Without any loose parts. 

 A smaller clamp on the 44mm Ø camera extension. Could provide further support at the tail end. There is no room on the Lunt, R&P, compact, focuser body for clamps. The camera's exact position is still an unknown. Which is where the Lunt focuser comes into play. With assorted 2" and T2 extensions available.

  I think I am finally getting there. With a safe and working trial assembly for H-alpha etalon, linear tuning. I like the fact that no precise machining or expensive accessories are needed.   

 
 

  

 ~*~

1st October 2025 Sun photos with phone

 ~*~

  After hours of waiting for the clouds to clear I captured some phone "snaps" of the sun. T-S binoviewer, 26mm Meade Plossl, GPC, Lunt 1.25" Solar Wedge, Bresser phone clamp. I was using slight digital zoom on the phone's camera to better fill the field of view of the screen.

 It would have been better to have used a single eyepiece. The binoviewer has optical limitations and adds a lot of glass to the light path. Which must be addressed with a GPC. Glass Path Corrector. 

However, the binoviewer adds a great deal of  enjoyment to the visual view. It gives a real sense of floating above the solar surface. The detail seems to be greatly improved in comparison with a single eyepiece. In fact I struggled to see as much detail with only my dominant right eye. It seemed as if it was going repeatedly out of focus. Perhaps a symptom of my age. I struggled to see the numerous pores. Which were easily visible when using both eyes.

 I have yet to enjoy binoviewing in H-alpha with the new telescope. This is a tricky subject and requires strict adherence. To the optical spacing of the elements involved. My choice of an f/7 refractor was deliberate. To match the original Lunt 60MT. 

 The problem is getting the Lunt etalon far enough inside focus. Which would require the complete removal of the focuser. Not easily achieved but not impossible. I shall have to resort to my vintage metal lathe. To make an aluminium adapter ring. The rest of the optical chain will be hanging from this ring. So it needs to be accurate. 

  ~*~

30.09.2025 Tecnosky 102mm APO to Feather Touch focuser swap.

 ~*~

  Tuesday 30th. I was pleased with my new telescope optically. Though NOT the R&P focuser. Hours of fine adjustment would not allow smooth movement. If it was smooth, then the slow motion stopped working. Finding a balance was a nightmare! I emailed the dealer and they responded with a focuser instructions leaflet. It was useful guidance but didn't help me achieve smoother motion.

 By the strangest coincidence I had a Feather Touch 2.5" focuser on my 6" H-alpha 'scope. The one I wasn't going to be using again. Because it was too big and too heavy. Could the FT focuser be made to fit the Tecnosky? 

 It all hinged on the size of the rotation ring/focuser adapter. I donned clean and brand new rubber industrial gloves. For more grip and unscrewed both focusers. To discover an identical M95 [?] thread on both. Off with one and straight on with the next. My 102mm APO now sports an identical focuser but a Feather Touch instead of the original. The nominal 2.5" with 90mm drawtube movement have the same sized fittings! 

 It gets even better: The Feather Touch focuser is shorter than the Tecnosky by a whopping 50mm! When fully racked in. The same will be true for all the other 102mm f/7 FPL53 APO clones of course. 

 Which means 50mm more inward travel from focus. Binoviewing without a GPC or Barlow! While simultaneously allowing a wider range of diagonals, solar wedges, etc. Yet to be confirmed in practice but almost certainly true. Being able to use a focuser I already own is just a bonus. One less item to dispose of.

 More inward travel might mean a donor Lunt 60MT etalon. Can be ideally placed in the light path of an f/7 refractor. My f/7 refractor? Without having to saw a length off the main, telescope tube. We'll see. 

 I bored out an Omegon, 35mm extension to 52mm to a depth of 28mm. With the active length of the extension being 35mm. The added physical [optical path] length is only 7mm. It occurs to me that I could gain a further 10-12mm. By boring out the 2" push fit Feather Touch adapter to 52mm push fit. This has an M63 male thread and is only 19-20mm deep. The same adapter on the Tecnosky is 38mm deep. So there is nothing to be gained there. 

 The magic number we are looking for is 264mm spacing between the etalon and the focal plane of the telescope. The native focal length of my telescope is 714mm. The shortest I can make the telescope/focuser/etalon adapter is around 520mm. That still leaves 194mm. Even using the FT focuser and my mods to various parts leaves a shortage of 70mm. Which is not nearly enough for optimum etalon tuning. The 264mm figure is set by the power of the lenses in front of and behind the etalon. Which are supposed to send parallel light through the etalon. Then converge the exiting beam as if nothing was there.

 M63 is a fairly common thread size. I'll see what else is available in a thinner format. Telescope-Service sells an M63mm male adapter to 2" push fit for €61. At a fraction of the cost of the Starlight original. The T-S example might be considered preferable to chucking a €230 part in the lathe! One slip and ouch! 

 It would be possible to remove a focuser completely from the equation. Just find an M96 male threaded part to fit the main tube. RAF do a thin, double ended M96 male ring. Then you just need to add whatever is required to make up the missing 50mm. I suppose a 3D printer could manage a shallow flange with a male 96mm thread and 52mm internal bore. Or something suitable for holding a 52mm clamping ring. M63?

 Hang on! I have a ready made, threaded rotation ring on the Tecnosky focuser. Removing the centering screws will provide a fitting to go in the end of the main tube without a focuser. Or, leave the inner ring in place and unscrew the focuser body. Done. 

 There is a male M81 thread on the back of the inner ring. Where the focuser body fits. The two nested rings have a depth of only 26mm. More than enough shortening to fit the etalon. Now I need a 2" push fit adapter to fit the M81 male thread. Prima Luce make an M81 adapter but it only reduces to M63 male and costs over €100! Telescope-Service has hundreds of adapters but no M63 female to female connector to add the M63 to 2" eyepiece receptacle. Which would still need to be bored to 52mm for the etalon nosepiece. 

I could turn plain adapters on my lathe but not the fine threads used on telescopes. Ideally there would be an M82 female to M63 female adapter. That would use the Tecnosky focuser fittings. Without the focuser body. I could turn a doughnut ring to accept the Omegon extension but that can't be copied by others. I was hoping for a commercial plug 'n' play solution. 

 UPDATE: I'll delete most of this text after some editing. The image shows the way forward. A simple adapter sleeve. Using the original V-grooves of the Feather Touch focuser and the Lunt 60MT etalon housing. 

  

  ~*~

29.09.2025 Tecnosky 102mm F/7 FPL53 doublet APO.

 ~*~

  Tuesday 30th. I have a new toy. Designed to allow me to continue solar imaging. Without the burden of a hefty, six inch refractor and equally unwieldy equatorial mounting. 

 I find capturing whole disks rather limiting. There are those who can extract incredible detail from our sun. Using modestly sized refractors. It just doesn't inspire me to try and copy them. After my time in the observatory with my larger refractors I wanted more. The problem is my increasing age and reduced ability to lift and carry heavy weights. 

 So I bought a 102mm F7 APO. Not the TS. Because that was out of stock everywhere on the known Continent. I went with the identical Tecnosky. From the same factory but with a few cosmetic differences. I chose a doublet. To avoid alleged cool down time. Hopefully to save some weight too. Over the more familiar triplet optics. 

 It had to be a keeper. So I opted for the more desirable FPL53 glass. Even if the difference is only slight. I knew I would always resent not having bought the "best" option. This would be my first "proper" telescope. The first I had ever bought new. Every other instrument. In over 65 years of active astronomy. Had meant buying the optics and making my own OTA. 

 The medium fast, 4" refractor class fits effortlessly on the AMN5. ZWO's increasingly popular harmonic mount. The little, red cube can manage 11" SCTs and 10" Newtonians apparently. While still providing exceptional tracking performance. I had no choice anyway. I can no longer lift. Let alone carry a conventional German equatorial. One large enough to carry a big refractor. Nor could I leave one set up permanently outdoors. 

 The triple boxed telescope arrived just as I was preparing lunch. So there was an hour's delay before I was set up and tracking a cloud laden sun. Before that I had been testing its terrestrial capabilities. Examining the whites of the fierce eyes. Of upside down gulls out on the fields at 450 meters. 

 Testing the telescope's ability to handle high powers and even binoviewers. That sort of thing. I tried and recorded the focuser scale with each option. Star diagonal, solar diagonal, 45º terrestrial diagonal, binoviewer with assorted GPCs, zoom eyepiece and my Shorty 2x Barlow. It all worked. And, without needing to saw big chunks off the main tube. 

 The sun was often cloud covered. So much patience was needed. As I went through all the options available to me. Delving into a plastic basket of optical goodies. I was struggling to see much detail in the scattered sunspots. While using a single eyepiece through the Lunt 1.25" solar diagonal. 

 So I swapped over to the TS binoviewer and a pair of 26mm Meade Plossls. It still needed the 2x Barlow to really come alive. Then, for a few tantalizing moments I was hovering over a huge sun. Countless small and larger spots spread out beneath me. I was in orbit over the sun! Without warning huge clouds took over. That was the end of the day's trials. 

 It became so dark it really looked like it would rain. So I had to hastily start dismantling. To make the numerous journeys indoors. With all the precious bits and pieces. Telescope first, then the mounting, the tripod, plastic basket of accessories, extension lead. Put the rise and fall, observing chair back under cover. It remained dark but did not rain until much later. Typical!

   

  ~*~

24/29.09.2025 Solar images and new plans.

 ~*~

  Sun: I captured some images of the sun in H-alpha but couldn't download them. Because of a lack of Internet outside. In the absence of a wireless connection I need a 10m network cable. Duly obtained.

  Here are a couple of whole disk examples until later. When I can produce a proper post. The Lunt 60MT seems to be able to provide fairly even brightness and detail across the disk.Though both images are a little over-sharpened. 

 I have been monitoring the autumn sunshine. Where it falls and when. A position just outside the lean-to greenhouse enjoys the most sunshine. Except for early morning and evening.  

 I have heavily trimmed the front [southern] boundary hedge and the shrubs in the front garden.  Beyond the hedge is a large paddock. With my neighbours' house to the south over 100m away. So there should be no solar heating effects in that direction. I live in a small, rural hamlet. Surrounded by miles of fields and woods in all directions.

 If the absent neighbours, to the southeast, trim their trees and hugely overgrown hedges. I would enjoy even earlier sunshine. They have the builders in to renovate the place. At very irregular intervals. This after years of complete absence and destructive neglect. The renewed interest in restoring the property to accommodation. Suggests the soaring, larch hedges will soon history.

 Slow progress is also being made on the empty house to my east. They both share large trees. Literally trapped between the buildings.  This is all happening in an arc to my east and south east. So it all directly affects my morning views of the sun. 

 My raised observatory once offered clear skies to the east. I could see over their hedges. Until they grew into mature trees. The best seeing conditions were usually early in the morning. Then conditions worsened throughout the day. As my own house roof always lay just below the track of the sun. If the sun shone then the roof was hot.   

 I now foresee a new setting for my solar imaging. Just outside the greenhouse doors. Beside the gravel drive. Which runs north-south for 100m. Starting just east of the house. Some more shrub trimming would provide plenty of room for a tripod and more modest telescope. A space of at least a four meters square. Perhaps add a few paving slabs. To provide fixed locations for the tripod feet. Unless I build or buy a weatherproof cover to go out out there. I will have to carry the imaging rig in and out. Best avoided. Though I do not want a solid building darkening the greenhouse. 

 I am assuming that I will set up a computer desk inside the eastern corner of the greenhouse. Just my 28" monitor, keyboard and mouse. I have several outdoor tables to choose from. Any of which can easily be pressed into service. 

 The greenhouse will provide shelter from the wind. Though not the sun. Local shade is easily provided. Using black, gardening, weed suppression cloth suspended from the greenhouse roof. Temperatures can be adjusted by opening doors and skylights. It will usually be far more comfortable than sitting outside. Or in an open observatory. I will be able to easily monitor the telescope through the glass walls of the greenhouse. The AVX tripod is easily solid enough to allow raised legs. So the telescope will be well off the ground without needing to be visible beyond the hedge. Mass loading of the tripod is easily possible if needed in a gale.

 

  ~*~

22.09.2025 495mm, PrimaLuce, Losmandy fitting, dovetail plate.

 ~*~

  The 495mm PrimaLuce, Losmandy, dovetail plate has arrived. It missed the weekend deadline for delivery. The idea is to buy a new and much smaller telescope. Probably a 100mm aperture at f/7. To make a new, solar H-alpha, modified telescope. 

 The image alongside shows the new plate clamped to the AM5N. The finish  is perfect and nicely matches the metallic red of ZWO. 

 This very long dovetail was intended to trial mount my present, 150mm/6" f/10 H-alpha telescope. Which is too large, heavy and bulky. To allow me to carry it far these days. It is also so long. That it will probably catch on the tripod legs. 

 The plate is larger at 98mm wide and far heavier than I would ever have imagined. I am more used to the much smaller camera plates and a few, rather short, Vixen style dovetail plates. 

 The Losmandy style plate was established to carry larger and heavier telescopes. It also provides a stable platform with considerable, lengthways adjustment for balance of an unwieldy, H-alpha modified telescope. Which often have long, cantilevered filter assemblies. Hanging out from the focuser.

 PrimaLuce generously drills a lot of holes in these plates. Some threaded and others countersunk from below. To allow hex head screws to clamp accessories, like tube rings, from the underside. Without protruding or preventing the plate. From sliding through the loosened mounting clamps. For balancing the optical tube assembly along its length. 

 I am rather wary of swinging a large and expensive telescope from the tiny AM5N. My brain has yet to match the little ZWO. With the huge mounting I built for the observatory. Perhaps I should attach the new plate to a length of scrap timber. Something of enough length and cross section. To match the weight and dimensions of the 150mm/6" solar telescope.   

  

  ~*~

18.09.2025 Yet more solar imaging.

 ~*~

  I dragged the whole lot outside again. It is blowing a gale but I am fairly well sheltered around the back of the house. Cloud has steadily increased from the first moments.

 Most of the software seemed to be working as expected. Yet again I could not remember how to push the results of one app onto the next. I have only one image to show for today's efforts so far. It has a soft limb but is quite detailed. 

 14.45 It has completely clouded over. I have come back in but left the rig in place. It is not supposed to rain. I have no internet out there. So can't look up quick guides to the next steps. Finding the files is the main problem. 

 I have lengthened the tripod legs to lift the telescope free of the roof's shadow. While I sit in the lee of the shed. With the screen lowered as far as it would go. So as not to catch the sunlight.

 I should find a much longer HDMI cable. To allow the rig to stand further away from the computer table. Imaging over a roof is not going to provide the best seeing conditions. Though I am still experimenting at this stage. As I sort out my procedures and practical details. The plan is to sit in the greenhouse. At the south facing, front of the house. With the telescope just outside. Not remotely possible today. As the gale is being funneled down that side of the house.

 16.15 I have given up. The sun has sunk below the trees from this viewpoint. It was slightly too cold at 65F/18C in the shade and the wind. The sun's disk is brighter on one side than the other. This brightness rotates with the blocking filter. Not a good sign. 

 The surface texture after processing in ImPPG is artificially granular. Nor could I see the screen well enough. To be sure of focus or tuning. The cloud was scudding across the sun's image for most of the time I was out there.  All very frustrating.

 I need to organize Internet via WiFi outside the house. As the months pass this site will become ever more shaded by the house roof. So I should be moving to the front of the house. Where I can be sheltered from the wind in the greenhouse. The monitor and keyboard can be protected from showers in there. With a permanent hood to increase the contrast on the screen. 

  ~*~

16.09.2025 More solar imaging.

 ~*~

  Tuesday. Showers, sunshine and wind.

 By the most fortunate of coincidences a German astro dealer has just restocked.With the 495mm long Losmandy dovetail rail I needed. For mounting the long and heavy, 150/10 H-alpha telescope. Order confirmed.

 This afternoon seems to be sunny so far. With the wind having dropped for the moment. I shall make another attempt at solar imaging. 

 I am all set up and it has clouded over and is spitting with rain. The telescope is covered with a trailer tarpaulin. The 28" screen with a bin bag. The weather radar shows a single patch of rain heading over us from the NW. So it might yet clear. I'll leave it out there and turn off the power if it rains. Lots of blue sky to the north and overhead. Solid cloud to the south and west. Sunshine! Off we go again.

 I managed to focus the sun and tune the etalon. Though my view on the screen was spoilt by the brightness of my surroundings. I captured a few videos. None of which I could process in Autostakkert. Because the screen problems. It kept clouding over. Until, eventually, it had to rain. Then rain hard. 

 I brought in the monitor and keyboard. Left the telescope covered in the tarpaulin. The telescope is now safely indoors but the mounting and tripod remain outside. Along with all the electronics! Just waiting for a lull. The sky is covered in huge clouds. Now, as I sit here at the indoor PC the sun has come out again. Grr!  

 I need some kind of hard shell. To instantly pull over the telescope during sudden showers. A tarpaulin cover is too clumsy. It risks puddles falling. Precisely where one was hoping to protect the electronics. I have discussed animal shelters as covers at length but never got much further. It may be time to reconsider the idea.

 The problem now is having the captures on the mini-PC. I have to re-connect everything indoors to access the data. I have no idea what to do about this garbage Logitech Bluetooth "NOT-Wireless" keyboard and mouse. Life is too short to waste further time on this crap. 

 It seems that it is not illegal to sell product as "wireless" when it uses Bluetooth. Why would any company with Logitech's global reputation. Need to advertise this crap as wireless instead of Bluetooth? 

 It was always satisfying to get a nice new Logitech mouse or keyboard. With an implied guarantee that it would work straight out of the box. One of the suggestions to get BT working was to replace physical components in the computer and update the Bios! All that just to get a Logitech keyboard or mouse working as expected? So I can continue to familiarise myself with all new software. 

 I wasted another hour on the pathetic Logitech support chatbot. Trying to get me to do exactly the same things as the Windows support chatbot. Do they have some special relationship as global monopolies? I wonder how they sleep at night. 🙄 

 

  ~*~

15.09.2025 Gales and rain.

 ~*~

  Monday 15th Two days of severe gales and rain! I shall use the time to learn how to use the Apps and get familiarized with the system and get it up and running.

 ZWO Sky Atlas has been driving me mad! I couldn't get past the permissions screens. The reason was quite simple. I had the phone's font set to maximum size. Old age visual decline. The "Agree" button was pushed off the screen. Now fixed and I can now use the App. Now I just need to find the mount. There is no mount symbol on the screen or in the indexes.

 I have now connected my phone to the AM5N mount with Bluetooth. The phone couldn't pair with the mount but the Sky Atlas App had no problem. I had to find the Bluetooth button on the mounting. It was just above the blue LED. The Goto button in the App vanished soon after moving the mount with the arrows. Why? More research! It seems the button disappears if an selected object is too bright? Nuts! 

 I did manage to get a white light image from the Lunt 60MT using the ZWO ASI174. Using "Snapshot" in SharpCap. Through a double glazed window. The trees on the right are at 460 meters. They were thrashing about wildly in the wind. The field in the foreground was also in constant movement. Black and white image from the 174MM mono camera. Resized and sent by email between the two computers. PC and mini-PC.

  I wasted hours in the afternoon trying to connect a brand new Logitech "Wireless" keyboard. Tried with both computers via Bluetooth. The only option  since wireless is not possible. It isn't recognized and will not connect. Nor will the bundled "Wireless" mouse. I wasted more hours going though the windows and Logitech support garbage repeatedly! 

 Though I did manage to get mount control working in Sharpcap. So I am making steady progress. It is far too windy to risk taking it all outside to point it at the sun. There have been some ferocious showers and gusts today! 

 I keep reading forum posts and watching YT videos about the load capacity of the AM5N mounting. It is quite shocking how some user load their mountings to the very limit. The AM5N has a capacity of 44lbs or 20kg.With counterweight. 

 My 6" [150mm] f/10 iStar solar refractor weighs "only" 27lbs or 12kg. This is with its tube rings and the hefty D-ERF front filter in its cell. It is quite long at 120cm from nose to the outer face of the racked in focuser. 

 I'd want a fairly long Losmandy dovetail bar. To aid longitudinal balance and to more safely carry the considerable weight. Hopefully more safely in the ZWO's saddle clamps. 

 The image shows the 6" in my 10' [3m] observatory. Mounted on my massive home-built equatorial mounting. It seems impossible that this large instrument could sit on a four inch [10cm] cube! The considerable length would probably hit the tripod legs if it was pointed vertically. However, the sun and moon are never so high. The danger is during a meridian flip. I'd have to ensure it never flipped!

 

 ~*~

14.09.2025 First light with new H-alpha rig.

 ~*~

  Sunday. I am making good progress now but have yet to capture any solar images. 

 It is interesting how closely Lunt and ZWO match their red finishes. Prima Luce make accessories in the same colour. I could have a dovetail bar in red to match all the rest. 

 I simply cannot believe the retail prices of these very simple components. Having worked on CNC machines myself. I can vouch for their incredible speed, accuracy and finish. I suppose there must be some wastage. Where cosmetics matter so much to perceived or acceptable product "quality." This is just a matter of replacing cutting bits, mills and drills before they wear out. No doubt they have lower paid, unskilled machine "minders." As well as setter/operators.   

 Next I have to find a way to support the mini-PC and two power supply bricks safely on the tripod. This will lower the centre of gravity slightly. More importantly is to free the telescope. Of multiple cables dangling in mid air. With only a single mains extension lead out to the telescope. A multi-socket solves the problem of the distribution of power. 

 That just leaves the cabling for the camera to the mini-PC. I am rehearsing in my mind what needs to be done. To carry the telescope assembly [rig] in and out. Breaking the units down to manageable parts for carriage is easily done. Though time consuming in a sudden shower. Can any cables be left in place? I don't want to find I am holding something heavy. While it is still attached by cable. 

 None of this crops up with an observatory. Except for connecting the laptop. Which I carried back and forth with me to the house. One quickly learns to plug everything in. The mini-PC overcomes that problem. If, it can be safely installed with protection from dew and unexpected rain. While still being allowed to cool. Its case is very open. That's not a complaint. It just needs to be kept in mind.

 Hanging, triangular weight bags in sturdy cloth are available for tripods. Though perhaps not ideal for carrying the items mentioned above. The clumsy and poorly finished, AVX leg spreader plate is crying out to be replaced with something better. However, it sits too high to be of much use for storage. The large holes are meant for eyepieces but don't offer any useful support. For things like power supplies or mini-PCs. 

 I am not sure I want a simple carrying tray fixed down there. Not with these items sitting loosely. It would make carrying the already awkward and rather heavy tripod an even bigger struggle. Again no complaints about mass and stability low down. 

 The power supplies and mini-PC are boxy shapes with no fixings or hanging lugs. They can't just be hung from their cables! This needs further thought. I need simplicity, security and speed in their containment. Zip ties or Velcro? The mini-PC has a support plate. For hiding it behind a monitor. It only hooks on. There are no fixing points, holes or screws.

 The two power supply "bricks" fit perfectly on top of the leg spreader plate. I strapped them down well with long zip ties. Next is to find a way to support the mini PC. Somewhere under the pair of PSs. The is no room on top of the plate for the relatively tiny computer. The tripod legs and central tension rod make it physically impossible. 

 There are umpteen little plastic baskets available. For storing household items, stationary, etc. Strap one of these to a tripod leg and the PC can sit safely in it. Without inhibiting cable attachment. Or blocking a clear visual shot at the sockets on opposite faces. With space for the cable to exit without being bent too sharply. So rectangular is best. Not to mention freedom for the cooling air to escape. I'd rather not attach Velcro to the PC.

 12.30 Job done. I found an attractive, shallow, black plastic basket in the third supermarket I visited. The mini-PC fitted perfectly. Though I had to drill a couple of holes in the ends of the basket for the cables. To avoid the plugs being twisted sideways. The plugs fix the mini PC securely in the basket. Without the need for any mechanical fixing. All the cables are now attached and the basket hung between two tripod legs by zip ties. Images coming after lunch. The white USB cable will disappear once I find another white, wireless keyboard.

 It was a sunny afternoon so I have been outside. Testing the wireless connection and tracking. I captured a few videos but haven't processed them yet. The mini computer connected to the indoor router. Though the ZWO mounting did not. The monitor screen is hard to see in such bright light.

 I now realise that I don't need Wi-Fi to the mount. The mini-PC is connected via Wi-Fi. With the mount on the end of a short USB cable. Using ASCOM to control the mount. Sharpcap Pro controls the camera but did not provide mount control. I did not persevere with this. The controls were shown and are much the same as ASCOM Mount.

 

  ~*~

13.09.2025 It came off in my hand!

 ~*~

  Saturday 13th. 12.00. Unlucky or lucky? I have spent the morning undoing a very nasty moment. I had fitted a longer dovetail plate to the Lunt 60MT. It looked silly how the little telescope fitted on the AM5N. Using the clamshell on a short dovetail plate. It was far too low in the clamps.  

 I then made a hideous mistake and chose to use a longer camera dovetail. They were the only dovetails I had handy of suitable length. Once I had the telescope mounted on the pate and clamped up. I tried to lift and move the telescope around. Just to ensure it was firmly held. It instantly came away in my hand! This could be repeated at will. 

 The geometry of camera dovetails is nothing like the standard Vixen. The angles are wrong and have much smaller contact surfaces on camera dovetails. 

 There followed a prolonged search through my tubs and drawers of astronomy kit. For a proper telescope dovetail plate. I found one but it would not fit the Lunt clamshell. Not without major modification. The dovetail had a flat base. So nowhere to lose the head of a hex bolt. Moreover it had a curved top. So nothing would fit unless I filed the dovetail flat.

 I found a pair of 90mm tube rings. I decided to fit those on the longer dovetail. Instead of the Lunt clamshell. Though this required a UNC1/4 x20 screw and I had only three or four. Some too short and others far too long. They came with the various tube rings. Which I had accumulated over the decades. One screw had a countersunk head. I used that on one ring into the threaded hole in the dovetail plate. Two large washers overcame the hollow face.

 The end hole in the dovetail plate was plain. So I used a hex head screw. Of course I did not have one the correct length. So I had to use an angle grinder to reduce the length of both screws. Otherwise they would have pushed the dovetail out of the clamps. I also had to drill the back of the dovetail as a counter bore. To sink the hex head screw to flush. Or it would have dented the Lunt's main tube. Just as the idiot who tested my Lunt at the dealer had managed to do. 

 So now, hours later, I have tube rings holding the Lunt 60 to the AM5N. I put the clamshell back on to hold the sun seeker sight. It fitted nicely between the tube rings. Time for lunch. I need a rest before I drag it all outside. Pictures to follow.

 I have successfully connected the AM5N via Wi-Fi. Controlling it via ASCOM ASI Mount. Now I am updating this blog post using the GMKtec mini-PC. I need a new wireless keyboard. As I am having to move the Logi receiver back and forth between the indoor PC and the Mini. Found an old one upstairs. The letters "A" and "S" have worn off. I have just found a working Logi mouse from my Observatory junk.

 17.00 I was going to play with the new toys outside but it clouded over. I experimented with bringing the new solar rig back in. There are several assemblies which might be carried as one, two, or three parts. This time I removed the telescope first. Then the AM5N mounting on the pier extension. Then the tripod. 

 The tripod has such a leg [foot] spread. That it has to be rotated to get it through doorways. I could loosen the leg stretcher slightly. Then rotate the plate. Which would allow the legs to fold in slightly. This can't be done safely with the mounting or PE200 in place. After the shock this morning. I have no desire to carry the telescope attached to the mounting. In case they auto-detach. Though it is very unlikely with a proper telescope dovetail in place now. I must see what is available in Losmandy dovetail plates. More expense! 

 

  ~*~

12.09.2025 GMKTec K6 mini-PC.

 ~*~

 Friday. The postman has delivered the tiny computer. My first of the Lilliputian  type. Yet another Chinese product. Which is superbly packaged and presented. 

 Once I had moved the mouse and keyboard over to the K6 it was no different from starting up any other computer from new. It was a lot faster than my aging PC. Even though I had fitted SSDs to the old box.

 I have downloaded and installed the ASCOM platform and all the usual imaging software. ASI mount and camera drivers. 

 Sharpcap Pro won't connect to the mounting. It's probably just me not doing it correctly. I'll try again tomorrow.  

 The fans produce a soft but quiet sound. No discernible tone or irritating whine. It fell silent, to my deaf old ears, when I put it on the lower shelf of the coffee table. 

  

 

 

  ~*~

12.09.2025 Arrival! AM5N + PE200 + GMKtec K6.

 ~*~

 Friday 12th. Sunny periods. I am hoping that UPS actually deliver my new mounting today. I have email updates suggesting they are on their way. They sent me emails saying they were going to deliver yesterday. While the parcels were still half way across Germany! The postman should be bringing my mini-PC today. Nice bloke. He has been doing the local deliveries for years.  

 Both deliveries have arrived. The ZWOAM5N is beautifully presented in a useful and sturdy cast case. The finish on the mount and pier extension is flawless. Nothing had prepared me for how small it was going to be. Though it was definitely not the AM3. Because AM5 is printed clearly on the side of the mount. The mount is surprisingly heavy. I wasn't prepared for that either. 

 The pier extension is nice touch and allows several more sturdy tripods to be used. In place of the CF original from ZWO. This shows a heightened level of care for customer's needs. 

 I suppose it took me all of ten minutes to unpack and assemble for the first time. Fixing the pier extension to the AVX tripod with the supplied round plate. Then added the mounting to the pier extension using the original, larger, round plate. The clamps on the pier extension are a nice touch. No long term pockmarks from thumbscrews. Perhaps causing buyers of used goods to haggle the price down..

 I have already adjusted the mount for my latitude of 55ºN. It only took a couple of seconds. The mechanical adjustments all work smoothly and effortlessly. No need for any other tools than the supplied hex/Allen key. Nor huge muscles. No frustration or dodgy threads to overcome. 

 I had to rotate and move the mounted tripod. The whole thing is easily managed. Very positive. I feared that lifting the completed assembly would be a strain. It wasn't. Not at all. I can carry this about outside. Plans for an off-road dolly can be put on hold. 

 Next is to connect it to the mains. I bought a12V10A PS brick. The dealer didn't have the original ZWO 10A PS. Only the 5A model. The weather is thundery with cloudbursts. I hope that isn't ominous! I shan't be able to take any pretty pictures of my new toys. Not until it clears up a bit. Another cloudburst and very deep rumbles.

 I need not have worried. The mount slews quietly and smoothly. Returning to Home with a press of the lower button on the remote/joystick. Fitting the dinky little, Lunt 60MT solar telescope. Brought the AM5N back down to earth in apparent scale. It will need a much bigger telescope to make it look tiny again. The fitted dovetail seemed lost in the AM5N clamps. I have much bigger [wider and longer] dovetails. Which never fitted any of the camera heads I owned. Now, they may finally be used in anger.

 Next I have to fire up the GMKTec K6. I'd better start a new blog post for that.  

 

  ~*~

11.09.2025 Celestron AVX Advanced Tripod.

 ~*~

 UPS [Oops?] delivered as promised but brought only one item of three! Despite notification of intended delivery, of all three parcels, this morning. They were lying. Two parcels haven't yet left Germany! Despite having arrived at the UPS export depot at Langehagen. Yesterday at 11.37 in the morning. 10.9.2025.

 So you'll just have to feast your eyes on the sturdy Celestron AVX Advanced tripod. 53mm stainless steel, main, tubular legs. The stiffness of tubes rises to the fourth power of the diameter. There is no real substitute for leg diameter in tubular tripod legs. Regardless of the thickness of the tube walls. Or their material. The AVX tripod stands 72cm tall in it's sock feet. No spikes are possible unless the owner drills and taps the solid, plastic feet. 

 These AVX tripods are difficult to come by without the matching equatorial mounting. At least according to forum members complaints online. This was the last one in stock at Telescope Express in Germany. [Orders accepted for restocking.] Telescope Express suggest these tripods are a fine base for swapping to different mountings and for DIY builds. 

 I can't tighten the leg spreader yet. Because the top thread needs to be screwed into a mounting or pier extension. Neither of which were delivered! 

 The AVX Advanced tripod fully extends to 126cm high. From the ground to the top surface of the head. The complete tripod weighs 7.7kg or 16.8lbs according to my digital scales. More weight means potentially greater stability against tipping for a mounting. Or should. Stiffness of the assembly is dependent entirely on the design. Where ground clearance is not a problem then the telescopic legs can be usefully adjusted downwards in length. 

 Any weakness in the raised/extended condition will be the result of flexure at the clamping joints [castings] between the two leg sections. I could detect no flex. Stainless steel bolts and stainless steel Nyloc nuts show care in design and attention to detail. Longevity without rusting is thus assured. This is not just a cosmetic issue. Rusted fasteners can make disassembly impossible.

 The other potential weak spot is at the tripod head. The legs must be firmly attached securely to solid metal. Preferably with the widest possible hinge. To avoid torsion and flexure around the hinge. The AVX tripod shows substantial, aluminium, cross sections are used. 

 The top plate has very reasonable depth and thickness in all its various sections. It looks fine to my eyes. The photo was taken with the tripod inverted in a flower pot to protect the finish. Though the tripod already shows signs of "clumsiness" at the factory. Fortunately only of a cosmetic nature. Mostly scuffs to the finish on the top castings of the legs. The marks may well wipe off. I haven't tried.

 The thickness of the cast metal is easily seen in the inner screw holes of the leg tops. I am not sure as to the exact purpose of these threaded holes. Some sort of fixing for the stainless steel leg sections? Further, more careful examination suggests there are rivets inserted here and the holes are not threaded.

The top surface of the head. A substantial casting with good depth where required. Reinforced by carefully chosen material thickness provided in all planes. The use of geometry to achieve strength and stiffness. Without resorting to a solid [agricultural?] block of metal. Which would be pointlessly heavy.

 The post projecting from the top plate is to locate a mounting. So that the same tripod leg is always pointed north. To save the user possible confusion when polar aligning. This post will be unscrewed once I receive the pier extension.    

 The large hole in the top plate is for the base of an AVX mounting. Or, to accept the adapter plate for another mounting. Or, a pier extension. The central tension rod pulls the fitted item securely downwards. To avoid flexure, tipping or vibration at this vital interface. At the very high magnifications used in astronomy the slightest flexure can lead to vibration. Whether the assembly is touched [for focusing] or due to gusts of wind.

 The tripod's leg spreader is simultaneously lifted between the tubular legs. Increasing the stiffness of the tripod assembly by pushing the legs outwards against fixed, stop surfaces. A useful geometric ploy much used where quality tripods are concerned. This also prevents the legs from splaying beyond control. 

 The leg stops, in this case, are arranged between the tops of the leg castings and the underside of the head's top plate. A useful provision to increase the stiffness of the entire head to leg interface. The head effectively becomes much thicker. Thanks to the leg, top casting pressing upwards. Both surfaces simultaneously resist compression. Backed up by the adjacent assembly.

Meanwhile the weight of the mounting, telescope, counterweights and all the accessories are pressing downwards on the top plate. The tripod's head/leg joint effectively becomes solid metal. Clever!

 I had hoped to show the PE200 pier extension fitted. This will have to wait until UPS gets its act together. As the name suggests: The pier extension lifts any fitted mounting by 20cm. Helping to reduce the risk of collisions of the telescope or its accessories with the tripod legs. Or to avoid the snagging of dangling cables. 

 Click on any image for an enlargement. None is larger than 1000 pixels per side.

  ~*~

9.09.2025 AstroBlender's AM5N + AVX tripod load tests.

 ~*~

  Tuesday 9th. I have ordered a ZWO AM5N harmonic, equatorial mounting. The first new mounting I have bought in my entire life. The rest have been [very] secondhand or home made. I also ordered a PE200 pier extension. Which allows a straight fit of the AM5N. Onto the AVX Advanced tripod from Celestron. While the increase height provides extra clearance from the tripod legs.

 My decision to go ahead was largely thanks to AstroBlender. A YouTuber who has posted several videos of his AM5 and AM5N carrying very large instruments. If his mounts can  track so well with large and heavy loads. With their centers of gravity so far from the mounting axes. Then my solar refractors should perform well too. He uses the AVX tripod to excellent effect. The 2" Ø stainless steel, tripod legs no doubt add to the rigidity and stability. 

 https://youtu.be/br4FdD3H_NM?si=vZJigEpKe4OT-Sf0

 I will have to make an off-road trolley. To allow the complete imaging rig, on its tripod, to move along my rough, gravel drive. Preferably with zero risk of tipping. To find unobstructed sunshine between the trees.  

 The next stage is to discover how to remotely control the mounting, telescope and camera. I need my large [28"] HD monitor. Just to be able to see and read the software screens. Mobile phone control via apps would be impossible for me to see out of doors. I needed a magnifying glass even with my HD laptop. Which has a near 40cm [15"] diagonal screen.

  ~*~

8.09.2025 Window shopping for harmonic mounts.

 ~*~

 I have been pressing my nose against the online dealer's virtual windows. As I struggle to decide where to invest in a new mounting. A traditional equatorial will just not do. Far too heavy and needs counterweights to match the fully sky ready OTA. So it's got to be a harmonic mounting. [Aka. strain wave] I can no longer manage to carry anything very heavy. Carrying being the operative word. If I had to carry a full solar imaging set-up 120m to clear the hedges it would kill me!

 The ZWOAM5N is probably the most popular harmonic mounting. It is reasonably light, mostly well regarded and now well proven. With many reviews carrying large and quite heavy instruments. Though it's base price rises rapidly with vital accessories. The vital pier extension and even a power supply do not come with the mount. The counterweight shaft and counterweights too. If anyone plans to push the OTA weight limits too far towards the 20kg maximum load. Rumours of a larger AM7 remain mere vapourware. The cost is likely to be much higher than the AM5N.

 The HAE69,  from Ioptron, can carry more weight than the AM5N but is rarely reviewed. The company does not enjoy ZWO's reputation for reliability, quality control and finish. All the other names seem to offer no particular advantages. Nor greater weight capacity.

 I am still investigating where I could mount permanent piers to image the sun. Preferably at all times of day and year round. Even it means installing several "posts." With an emphasis on early morning and early evening imaging. When seeing conditions are usually most favourable. 

 My absent neighbours [and myself] have added huge trees and hedges to the landscape over the years largely by neglect. Which makes unobstructed imaging sites extremely hard to find within the local area. Except at the height of summer. When the sun is high and rises and sets usefully. In winter the many trees come into play. Throwing long shadows over the entire area. Yet ironically, the sun shines cheerfully just beyond my boundary hedges.

 

~*~

 

7.09.2025 You call that solar imaging? 😄

 ~*~

 Sunday 7th. A sunny day but the sun was often veiled by thin high cloud. 

 I dragged my Lunt 60MT out and put it on my Manfrotto CF tripod with the gimbal head. There followed several hours of struggling to capture anything worthwhile. Image scale was fine using the ZWO ASI174MM without a Barlow. 

 I  really wasn't prepared for the laptop. It was still stuffed with ASCOM and AWR drivers for my huge DIY equatorial mounting. So it kept wanting to do silly things I no longer needed. Which meant I had to delete a lot of unwanted software and drivers. 

 I was used to a 28" HD monitor in a darkened observatory. Now I was out in the open without any shade for the small laptop screen. Now I had to make frequent use of a magnifying glass. Just to be able to read the text. I couldn't for the life of me remember the sequences. For the various capture, stack and image enhancement software. 

 Eventually I had dimmed the image enough to capture some H-alpha videos. Adjusted the mechanical length to just reach focus. Pressure tuned the Lunt endlessly for sharpest H-a detail. Onto stacking and I was stuck again. This is software I used for literally hours every sunny day for several years.

 It was so automatic back then. That I was usually capturing the next video live. While I was fine tuning the final appearance of the last attempt. Hundreds of videos, stacks and final images per day. Production line close-ups from my heavily modified, home-built, DIY 6" refractor. Now I was working on full disk with a tiny telescope on a fixed mounting. The image wasn't remotely even across the width of the sun. I could hardly see the image on the laptop with so much light bouncing around. 

 Well that's my excuse for the image above. No sharpening or enhancement. Straight out of stacking from a whole screen grab. You can even see where I clicked on the image without progressing further. 😳

 

~*~

25.08.2025 Reality beckons. Optics for sale.

 ~*~

  Monday 25th.

  My lifetime passion for telescope making is finally at an end. 

 I have demolished my entirely self-built, 2 storey observatory. The loss of a permanent mounting means lifting heavy OTAs is equally at an end. My sturdy, DIY dome supported several pulley systems. To aid lifting my telescopes into place above head height. 

 I am 78 and don't seem to be getting any younger. At least not according to the bathroom mirror. Which I believe is perfectly normal. The mirror, not the old man reflected there. 

 I have some interesting optics. Which might well interest others. The problem is where to advertise them. 

 Stargazer's Lounge has a European small ads forum. With only a small number of ads. Compared to the huge number of ads in the UK section. Does anybody read the European list? Who knows?

 I am banned from Cloudy Nights due to the mention of modified and self-built, solar telescopes. 

 Denmark has a tiny population and therefore far fewer amateur astronomers than the UK. A small ad in one of the general, online, small ads websites under "telescopes" is unlikely to be seen by many potential buyers. 

 Facebook has online ads but who knows the geographical coverage? The largest market is the US. With some parcel services currently suspended due to Chump tariffs. There is also the problem of import taxes. Which can make purchase limited to those seeking a particular item which exactly matches their needs. Currency exchange, heavy postal charges and ensuring payment is also an issue.

 Listing my items here is unlikely to reach many amateur telescope makers. International postage of large telescope tubes is impossible or hideously expensive. So only the objectives [an focusers] can be sent. Which further limits interest in buying for some amateur astronomers. 

 Few have access to the tools or the necessary skill to build a complete OTA from scratch. Though it is remarkably easy if you have access to the straight seamed, thin steel ducting I use. Not the ugly spiral seamed tube. The straight seamed ducting is intended for dust extraction in furniture factories. Where fire is a serious, potential risk. Being galvanized and intended to be exposed for decades. It is attractive and an ideal material IMO. At 0.3mm thickness it is certainly no heavier than aluminium tube. Which must be thick enough not to bend under its own weight. I never saw any rust on the tubes I selected from the vast heap outside the local furniture factory. Usually for the small price of a contribution to Friday cake day.   

 Some of the items I want to part with include:

 A signed 10" f8 [250mm] Lockwood parabolic [planetary] mirror 1/30th wave in original packaging. Lockwood's optics are very well known and respected in US astronomy circles. Though he is usually too busy to make smaller mirrors these days. I was able to effortlessly view several small craterlets in Plato on the Moon. Sadly I was never able to build an OTA of low enough weight to match my decreasing strength.  

 Such an OTA could be mounted as a Dobsonian Alt-azimuth on rollers for concrete. Or a stable trolley with wheelbarrow wheels? My sky is far too blocked by trees now. To use one in my own garden. I'd have to travel at least 120m just to escape the absent neighbour's hedge.    

 An iStar 7" F12 R35 [180mm] refractor objective in its collimatable cell. I mounted this in an 8" diameter steel [ducting] tube with a 3.5" Starlight Feather Touch focuser with slow motion.   

 I also built a folded version. Using two, superb quality optical flats of 3"&4" imported from the USA. All of this can be read about and is heavily illustrated in the earlier posts here on my blog. From around 2015. Where did the time go?

  An iStar 6" f/10 [150mm] H-alpha corrected refractor objective in its collimatable cell. I also have a matching Baader 160mm D-ERF full aperture Solar blocking filter. Mounted in a Telescope Express aluminium cell. It has [had?] a 2.5" Feather Touch focuser with slow motion of course. The Starlight Instruments focusers are superb and well worth the price over mere pretenders. 

 This makes a large aperture, solar refractor for high resolution imaging. But only with the necessary etalon and blocking filter. Or a Quark? You'd have to buy your own filters. Or dismantle a smaller H-alpha telescope. To obtain these vital parts. I posted lots of successful H-alpha images on various Astro Forums and here on my blog. Both objectives can be used for white light, lunar and planetary imaging of course.

 Do not fool yourself that any of these optics can be mounted on a flimsy equatorial on a lightweight tripod. The resulting telescopes need very adequate support. I doubt my home made, massive equatorial mounting holds any interest. Except for those with the skill and tools to complete it to their own standards. Even my heavily reinforced [Beacon Hill] worm housings simply flexed too much for accurate GoTos. Though it tracked very nicely for many hours once it was centered on the sun or Moon. And often did! 

 

    ~*~

8.08.2025 Lunt LS60MT repaired! 😊

 ~*~

   My Lunt 60MT has been returned by Bresser. The Lunt distributors for Europe. They had replaced the blue and the UV/IR filters free of charge under guarantee.

 The telescope is back to normal and tunes in H-alpha near the start of the thread. It was rather cloudy at first but thinned. Enough to be able to make out lots of nicely sharp proms and surface detail. I tried a variety of Meade 4000 Plossls. Ending up with the 9.7mm for ~43x. 

 I cannot honestly confirm whether the telescope is better or worse performing than before. I so rarely used it visually. The etalon and BF were mostly used for imaging in the 6" f/10 and that was over three years ago. 

 I completely lost interest in everything after my wife died. Only now am I rebuilding my enthusiasm for solar. To the tune of ordering a cheap zoom eyepiece. An Omegon Magnum 8-24mm and a Lunt Sol Searcher sight. I don't currently own any equatorial mounts. My huge and heavy DIY equatorial has been dismantled. 

 I tried my TE binoviewers in the 60MT but was unable to reach focus. With the 1.25" TE star diagonal in place there wasn't sufficient inward focus. I tried with a Shorty 2x Barlow and a 2.6x GPC but no. The problem is the star diagonal. It adds too much to the light path. The sun was far too high to use the telescope without the star diagonal. 

 I already owned a straight through, Lunt B1200S2 blocking filter. So did not order a Lunt Solar BF diagonal containing a blocking filter. When I ordered the 60MT telescope. For its much bigger etalon than the Coronado PST. Which I had been using previously for high resolution imaging. 

 I understand from users online. That binoviewers can reach focus with the BF diagonals and a Barlow or GPC. Though there are binoviewers with 1x power and zero light path. Which have received rather mixed reviews. They are also quite expensive. Making the potential purchase a costly exercise in folly if they should not suit me. 

 Besides, I prefer much closer views than the LS60MT can manage alone. The problem is finding a mounting which could cope with my long and heavy 6" f/10 H-alpha refractor. I need to be highly portable to be able to see the sun for most of the day. Due to all the trees and hedges around my home. Which probably means a strain-wave mounting. Which may not be able to easily manage my 6". Whatever the manufacturer's load capacity claims. 

 The mounting has to be properly supported. Depending on the telescope load applied. Its length, weight and accessories. Which means a tripod has to be carried as well. The lightest carbon fiber tripod might not be ideal. Now, as I approach 80 I have to consider the risks of dropping very expensive equipment. It is no longer a matter of climbing up to my second storey observatory and simply opening the shutters. 

 I could use a smaller, shorter refractor. Say a 100mm f/7 to better suit the 60MT etalon. The 6" iStar objective, with its expensive, front mounted D-ERF, would have to be sold. To help to finance a much more portable set-up.

  ~*~

6.08.2025 Near 100% cloud cover.

 ~*~

  Wednesday the 6th Bresser has returned my Lunt 60MT solar telescope form their repair department. With the blue and UV/IR filters replaced free of charge under guarantee. 

 I quickly dragged my Manfrotto CF tripod outside and mounted the telescope. There were a few blue patches between the clouds and some of them crossed the sun. Often briefly, as Storm Floris moves ever away.

 I was able to sharply focus several group of sunspots but no sign of any other details. I unscrewed the pressure tuning knob completely to zero to atmospheric air pressure. Then began to screw it gently back in. 

 Just as I reached the fully inwards position I was rewarded with sharply defined prominences. Though still no surface detail on the sun. This coincided with 100% cloud cover! So it all had to come back indoors again. 

 It occurs to me that the tuning pressure could be increased with a taller piston. Which means the same thing as adding something to displace air volume above the piston inside the brass cylinder. This would achieve tuning with the tuning knob further out for exactly the same pressure. 

 Which might be useful where the knob must be screwed fully in to tune to H-alpha. Whatever I use to boost the piston volume should have a central hole. To allow the compressed air to freely enter the etalon housing. There is no need for the packing piece to be fixed. Because it cannot escape. 

 Though it must be made to match the cylinder bore with some clearance. If it were much smaller it might jam between the piston and cylinder face. Before the necessary compression is achieved. It must be made of some reasonably dense material. Like metal or plastic. To avoid it simply absorbing air as it is compressed in the cylinder. So foam, for example, would be a poor choice.

 There were fleeting moments of sunshine in the afternoon. I tried again and was able to tune with the knob well unscrewed. Unfortunately the sun was never truly clear of cloud. So I was denied a sharp view in H-alpha. Though it did look promising. With lighter areas clearly defined in better moments. I tried taking a few snaps with my phone but the sun was completely overexposed. 

 

  ~*~