Rusted

Back in the 80s I made an 8.75" F3.8 truss tube, rich field Newtonian using Rawlplugs. These were rubber "top hats" with a screw to compress the plug once inserted into a tube. I put the Rawl Plug screws through holes in the baffle and then added the tubes. Nowadays there are also expansion plugs in split brass bodies with conical expansion "wedges." Used for anchors in concrete, etc, in a wide range of diameters. Expansion plastic plugs with built in screws are also handy for getting a solid grip inside a tube. Bung a right angle bracket under the screw head and reinsert the screw and you have a really solid fixing. Cost is bound to be a fraction of CNC'd kit with a named astro label added from a factory in China.

Hi BP and thanks. What do I gain with Virtual Dub? Second question: What is that amazing telescope in your avatar? That looks like a skeleton solar refractor top end with an internal D-ERF. PS: I have just found the details of your solar refractor on CN. Thought it looks as if you have made some changes since then. I'm very tempted to turn my iStar 180/12 R35 into a folded, solar refractor. Though the image scale would be huge at 2160mm f/l. And highly seeing dependent. The Zerodur flats would be better protected with a full aperture 180mm Baader D-ERF. [At the cost of several kidneys] Rather than my present 90mm internal D-ERF.

A difficult task for such complex, yet abstract subject matter. Though no doubt something you are well able to achieve. Too many video tutorials are overlong and far too full of detours. IMHO. Understanding the whys of the effects achieved may well be beyond many imager's ability. Perhaps it is the Darwin effect and imagers really must be highly competent specialists. They must be able to absorb and retain lots of fine detail to succeed. An academic mind, being gifted or having an innate ability are vital to achieve anything really worthwhile. If imaging was too easy then we would be swamped with countless, perfect images. A "Press Here" button may never be possible until we all have access to AI. And what then? We could rapidly become intellectual pygmies. Faced with a technological force completely beyond our comprehension. Everything we believed in would wither overnight. The "hunger" for knowledge, like our genetic hunger for things, would simply vanish. We would become mere spectators of our own demise. Perhaps the real truth is, that if it wasn't very hard, then imaging would not be worth doing. We "mere mortals" must make do with constant practice and tireless effort to polish our skills by iteration. There really are no short cuts even for those with ample funds for equipment. Though having constant, perfect seeing conditions must be considered as cheating.

Thank you both. This may not be the best place to discuss the mechanical details but it raises a number of issues. I like to think of all the solar imagers and modders out there who never ask questions on forums. So they must rely on random opinions and hope it helps. An interesting suggestion BP but my etalon is in the approved position. Though certainly worthy of further experiment. You may not have noticed that I am using a 1.25 GPC to correct the f/8 objective. I usually see very much finer detail than your posted image on my 25" monitor. [Seeing permitting.] If the camera can capture all that fine detail "live" then I doubt there is very much wrong with the basic set-up. Processing software is always my Achilles Heel. Operator error!?!? I have now given up on Registax because of the constant crashes during Alignment. It was actually making my final images look much worse than the individual video frames after stacking! So Autostakkert is exercising my few remaining brain cells now. With returns to Registax only for Wavelets. Last night I found a ~2 hour YT streamed video on solar image processing by Simon Tang @ Telescopes.net/Asteroid Hunters. Well worth watching and I intend to study it repeatedly until his exact methods sink in. The way he used iMPPG and other free softwares was quite startling in their immediate effect. I find his methods and online treatment rather more "accessible" than other help videos. I shall have to note the exact video times for the vital bits to reduce the effort in wading repeatedly through all "the padding." I have a number of mechanical & optical issues I'd like to address. The tilt of the internal 90mm D-ERF is an unknown. I get a lot of asymmetrical variations in brightness which is not addressed by the tilt plates but does change with etalon tuning. The D-ERF sits on an original Celestron baffle which is just jammed in place to allow full aperture clearance for the hot light cone. A full aperture front D-ERF would allow easy access instead of being buried half way down the tube. Downside is the very high cost. The Aries D-ERF was too similar in basic price to warrant the large investment. I'd have to add 25% VAT on top of the price + freight + customs clearance + import taxes. Making the Baader D-ERF [almost] a bargain. I have a motor driven etalon tuning project waiting endlessly on delivery of shorter timing belt from the UK. It's usually a 3-4day postal service but has been weeks! I think they must be ordering in from China whenever they get a hit on eBay[UK]. The sole, Danish, online dealer had run out of precisely the belt length I needed. I'm very tempted to make a skeleton H-alpha OTA to give me easy access to all the components on collimatable cells in a rigid assembly. My 180mm/ 7" iStar could make an interesting PST mod donor but is f/12. The cost of the full aperture D-ERF would be terrifying! Perhaps I really need a Quark but the QC sounds dreadful and I daren't invest that much until they can guarantee success!

Thanks. I am still severely handicapped by my lack of skill with the processing software. Sadly, I often see more on the monitor during capture. Than the dregs left behind in the bottom of the pot after giving the video a good stir.

I second the solar option as a valid hobby for the retired and perhaps the shift worker. The long summer season, where it never really gets dark in northerly climes, denies night time observation and imaging. Light pollution is affected in intensity by cloud cover and vice versa. The Moon is a blot on the sky for many imagers. Perhaps we should cost the hobby in Pounds/Dollars/Euros invested per hour of observation/imaging per year? Then compare it with the average post, entry level investment in other equally frustrating pastimes.

The image scale is extreme. On a "lunar orbiter" sort of scale. A bigger sensor would help but at much greater cost. The guiding, focus, mounting alignment, collimation, cooling down and seeing conditions would have to be spot on. [Not necessarily in that order.] The Moon is very low at the moment. Which does not bode well for perfect seeing conditions. I was only using 2.2m fl two nights ago 180/12 and the results were absolute mush! As to filters: The usual recommendation of Solar Continuum will make your image darker and fps much slower. Noticeably so in my case.

It can be done. Mine is14' high in a square pyramid of 4x4s. Only clad at the top with 3/4" ply within the observatory dome, above 1st floor level. Bases are fixed to massive, pyramidal concrete anchors with adjustable height steelwork. Totally isolated from the building except at ground floor level of compacted gravel. Others have used precast chimney blocks.

You don't want to do it like that... Get a proper set of railings. PS: Those are not Christmas lights.

Thanks Dave. I was quite amazed by the detail brought out by imppg. Sun too low? I'm at 55N CET [Edinburgh level] so I just use a taller stepladder.

Unless you are committed to aluminium tube you might enjoy thin galvanized steel ducting. Not the usual spiral stuff but with a single long, straight seam and smooth elsewhere. A tiny, radiused flange stiffens both ends without need for anything added. Handy for retention of large objective cells! Sold mostly for woodworking factories. Or where any potentially inflammable dust collects in the dust extractor system. Available up to at least 16" in diameter and probably more. I get mine off the scrap heap behind a local furniture factory for the price of a pint per 2m length. The seam fits nicely in Skywatcher type tube rings at the hinge gap. I have used the 8" tube for my 7" refractor and it looks authentically Edwardian. Doesn't mar like paint does. I also have a 2m length of 12" waiting for my classical 10" f/8 Newtonian with premium mirror. Another roundtoit. No greater weight than aluminium in the thickness you'd have to use anyway. Never really rusts and is only 1/3mm in thickness. Wonderfully stiff and never needs painting! I took the conical adapter for making a pier but have never used it.

Sorry to hear that Charl. 🙁 Get well soon! 👩‍⚕️ I'm struggling with variable cloud. How about this for fine detail? Inverted and augmented in imppg. Is it real, or not?

Small looped prom at 4 o'clock on the limb looks almost like a knot. Tiny image cropped from 640x480 then enlarged to 500 pixels in PhotoFiltre7.

I've cycled at down to -15C and that was before I discovered suitable clothing. It was agony on the hands and feet! Years later I discovered MTB winter boots and GripGrab two fingered mitts. Both will keep you cosy. You must have a windproof shell [not waterproof] to make any sense of layering. I have several windproof jackets all bought from charity shops. A bit dated but excellent wind stops. The Danes discard a load of cycling stuff and there are a lots of keen cyclists. I only use the jackets around specific temperature ranges to avoid overheating.

I have deliberately sat at the telescope at -23-25C showing on two digital thermometers. My collection of old down jackets can be layered if need be. Here I am well wrapped up. An utterly pointless exercise but I wanted to see if it was possible. The eyepieces fogged up in seconds when I brought my face anywhere near them. I was rotating two of them through my inner pockets and breathing downwards. Then there was the extension cable problem. It lay in a huge, rock hard, spiral "spring" across the yard for over a week. Memory foam has nothing on PVC cable which usually lives in a coil in the shed. We live at the bottom of a slope which causes a "thermal decline."

Making great progress Vin. Particularly considering how little sun there has been to practice on. You can easily rotate your images in free, image handling software if orientation bothers you. Help yourself by finding a non-slippery, black, shade cloth and wearing a black jacket, fleece, T-shirt or jumper. Avoid anything light which can reflect back from your screen. Even black will appear light grey in direct sunlight. A cardboard packaging, shade box can help but needs to be deep enough to provide enough shade. You can easily make holes in the sides for the cables in a cardboard box. Or tape something together from a bigger box. Ideally this needs a small table [or stand] and a chair so you can relax without dropping "stuff." Don't be too self-critical of your results. Every subjective failure is valuable lesson learned. Above all: It's supposed to be fun! Not a competitive sport! Well, not yet!

Tripod stepladders are superb. Lightweight, safe and stable with broad, comfortable steps. The huge span at the base makes a mockery of ordinary ladders with horizontal stabilization bars.

You had more luck with the paint than I did! My sage green top coat is already flaking off the white undercoat and looks a sight! Only complete rural isolation allows me to hide the shame.

Baader do a 1.125 GPC [Glass Path Corrector] for those who cannot quite manage the f/10 requirement. It acts as a weak Barlow to stretch the focal length less than the usual 2x Barlow. It also adds to the cost and complexity of the PST modification. I owe all my H-alpha/PST mods to expert knowledge from Peter and Ken.

When I were a lad.. I used the valley between the twin roofs of our Georgian slum as an "observatory." 4" f/15 refractor in a cardboard [carpet] tube with a [home made] simple, objective lens made of ophthalmic glass. Quite well corrected too, surprisingly enough. Which is more than you can say for me.

Absolutely amazing! You are a bit of a genius to have constructed that lot!

"Warning!!! Never use the Solar wedge without the supplied narrowband filter and the polarizing filter. Otherwise irreparable eye damage can result!!! TS." I routinely use a Baader SC in my 2" Lacerta prism along with a single rotatable polarising filter and the fixed ND3. The polarising filter is really valuable for adjusting a pure white image to a comfortable level. Note that you only need a single polariser to dim against the polarising effect of the prism. I have a rotatable collar, but with a 1.25" TS you'd need to move the polariser to each new eyepiece. Then rotate the eyepiece for comfortable brightness before locking the thumb screws of the receptacle. Not such a chore in bright daylight compared with fiddling with filters in the dark. Do we know if the TS "narrowband" filter is green? Any owners present?

John, If you read the TS blurb they do state quite clearly that the narrowband filter must not be removed. It sounds as if they are relying on the unnamed narrowband filter to further reduce the risk. Genuine Baader SC filters are very pricey even in 1.25". This would seriously raise the retail price of the TS solar prism if provided as standard. Suggesting, perhaps, that this may not be a Baader SC filter but something similar. This matters to TS solar prism buyers. At least those with a chromatic phobia. So greater clarity is highly desirable. IMO.

I should have a lie down first. You'll be exhausted after clearing all that snow off the tube!

You can use the SAFELY FILTERED Sun [or the Moon] to align in SharpCap. The Sun would need an approved solar filter [Baader Foil?] covering the front of the telescope. I used the sun because I wanted to do the alignment in daylight. I have a very heavy mounting and use a length of scaffolding pole to turn my telescope mounting horizontally. The idea is to align the camera's axis against a vertical crosshair first. A must do! You move the camera's image up and down, parallel to the vertical line on the screen. You do this by rotating the camera in the eyepiece holder as you rock the telescope tube gently up and down. Then you can watch as the sun or moon drift up or down, or left and right, on the screen against the crosshairs. Any drifting has to be reduced by moving the entire mounting horizontally. Or by raising or lowering the Polar Axis of the mounting according to the rules provided in the video. I used SharpCap to enlarge [Zoom] the filtered sun's image to fill my laptop screen to make it easier to see any drifting. If you write down or print out the rules for changes to the mounting's orientation it will be easier than trying to remember them. It all sounds horribly complicated but is actually very easy if you just follow the rules in the video below.