Chriske

The very first error has nothing to do with this new astigmatic pattern, as you can see. Twee different causes.

You need to adjust the heat to just one, or two degrees above ambient. Just enough to keep the dew away from that SM. But as your SM has already astig, when cold, there's another problem. Looking at the surface of the aluminium I think that sheet of alu is most probably hardened alu. Meaning that sheet of alu is full of strain. That has to be removed first. Now as it is heating that sheet of alu the tension in the alu get worse and pulls on that mirror. You need to remove that strain by softening the alu. Sadly enough you need to remove the mirror first from that sheet of aluminium. If you do not know how let me know. BUT what I do not understand is why the ast has a perfectly elliptical shape. Maybe just maybe it has nothing to do with that hardened sheet of alu. at all. First this : Are you ab-so-lu-tel-y sure that both these mirrors are free of astigmatism...!!! Maybe in the past you didn't notice..? Can the primary mirror move freely in it's holder. Just a fraction of a millimetre is enough. The clamps/hooks (to hold the mirror down), are they not to tight. Make drawing please, were are the silicone blobs located..? It's not a major issue, but it could reinforce the error you're dealing with right now.

Hold on, you're saying(if I understand it correctly) : no heating and there's practically no astigmatic error at all .. ?

Al done. Also adapter for another scope(blue)

Stu, Can I please use one or two of your pictures to show on a Dutch forum. There are a few non-believers here about pictures taken with a smartphone. That'll convince them that it actually can be done. Yours are far better then mine, but I think that will change in time. I hope to reach the same level as yours and that of others here on this forum. It's almost mind boggling what can be done with these small lenses in a smartphone. I fact it tells something about the quality of these little lenses...😳 Chris

I'm drooling all over the place....😱

Of course....! ... Why didn't I think of it myself, silly me... I thought only the FL would change position of the SP.

Btw...estimate cost for this printed holder is 6.5€ + a few nuts and bolts M3

Thanks...!...👍

Hey Stu, thanks for the reply. I can shift the SP 20mm sideways in both directions. The third movement (optical axis direction) planning to adjust even further. Depending on the F value of the eyepiece I think that needs to go even further(or nearer) But the latter is just a guess, not done this before at all. I'm jumping in a dark and deep hole here. Love it to do this project together with my son Steven...🤗 Anyway I'll keep you informed about our progress. Problem is now...it doesn't look good for the next days ....it's cloudy again...😟

Well, as a matter of fact, it crossed my mind. But owning a few printers I'd rather make my own. That's (to me that is) part of the fun.! this is what I've got so far... Almost done. I can adjust the SP in three directions with this holder. Busy printing the first part already. The longer part on the left fits around the focusserbarrel, 70mm diameter that is.

The picture above is taken handheld as I mentioned before. It is very hard to get the SP perfectly aligned with the scope's optical path. The SP holder I used before(see higher up) is not perfect. It is off by (not even) 1mm. So I will make me another holder. I intend to make it so that all three directions can be corrected if needed. Never gave it a thought that it should be so precise. Has someone else had that same problem...?

Yep, I am very proud indeed. Time to move on to our next challenge. It will be even bigger...!

This is one of the last pictures I will be posting. Standing on a ladder three four meter high, seen from behind HST, you see JWST in the background

Todays Moon again done with my smartphone. This time handheld. This is just one picture, so no stack and no Gimp

I'll ask Tom.

Woow thanks for the fast replies...!

A while ago my friend died and left me with that solarscope. There was no manual in the trunk that came with that little scope. So I do not know how this scope works. I do know how telescope work, I build/grind my own telescopes/mirrors. So that's not the problem. But this little scope left me with a few questions. Can someone please explain how to use that little Lunt. Thanks in advance.

Hi, Thought I post it here also because not all of you guys don't visit the ATM section of SGL very often. Just finished building a JWST scale model 1:7 To close that thread I also posted a GIF taken by a member of our astrophoto-club @ Urania, Tom Alderweireldt. imo a fantastic GIF of the speeding JWST to its final destination in space L2 Magnitude of JWST = m16 (estimate) Enjoy...

Bino is completely finished but due to covid these four mirrors are not coated yet. And on top of it we do have our own coater, but it needs a small repair. And yes I stay at home as much as possible. Except when working on my projects at our observatory, but when I'm at it I always work alone. No worries, in the past I've made a few Kutters, and also a few bino's...😉

During launch of JWST Christmas last, one of the NASA speakers said : That this will be the last time we would see JWST ever again... Well not exactly true. Yesterday one of the members of our local observatory Urania made a few shots of JWST. While speeding toward L2 at 0.35km/s it looks like this... Barely visible at magnitude 16... Tom Alderweireldt did a great job here, I'm most impressed...!...😳

Tomorrow after finishing JWST I'll give HST a "firm rub" with my feather duster .... Maybe Yvette would do that for me instead...😁

Nearly done, tomorrow last modifs, and final pictures.... Side by side with HST in our planetarium

Next test will be with a more recent SP(my son Steven). I also plan to take pictures with a camera. And no, not with a fancy, expensive and very heavy camera. I do not even own one of these. That camera I'll be using is just a simple thing with a fixed lens. But taking these pictures I have to move on to another forum I suppose..?

Thanks Stu, This is just one single shot, no stacking involved and no PS involved either. I do not have PS, I use Gimp instead(Linux). Whit this first shot I just wanted to familiarise myself again with AF. It's been a long time I shot the Moon. For this first shot I printed a holder to keep my SP steady.