Ags

I got plate solving working last night at a focal length of 970 mm. The trick was to plate solve in the AsiAir Preview mode, and then sync to the target. Plate solving during polar aligning and during object selection still refuses to work.

I'm amazed by the detail picked up in just three minutes with city light pollution and a 95% Moon. The scope was reduced (using my trusty SCT 6.3 reducer) to 970 mm focal length, so it was operating around f6.4.

First light. I think the collimation can still be tweaked slightly but I am pretty happy with this result. It’s hard to judge the star shapes as there was a bit of a breeze, but the scope is clearly functional now. This is one unprocessed 3-minute sub.

There is a lovely group I was hoping to photograph, but my laptop won't boot 🤨 Still, a lovely view in the eyepiece.

The Moon is always worth a look! Another thing to chase down are double stars, they are good regardless of light pollution.

I am waiting for my grandson to fly over with an 8300 mono, so looking forward to finding out for myself if CMOS is really better. In my case the comparison is between and uncooled OSC CMOS with amp glow and a cooled CCD with three times the surface area. It will be strange to have a camera with a physical shutter!

No, you ideally adjust the primary, secondary and the focuser! But with a smaller chip like mine you can get away with mostly adjusting the primary.

I am having no luck plate solving with the ASI485MC and my RC6 (reduced to a focal length of about 900 mm. The short side of the chip should still span around 0.4 degrees so it should be possible.

I took the scope out to align the finder today, and gave it a bit of a bump… I hope the collimation is still ok 😐 TS sell the same thing, never seen it called a Reego before. It looks however that I can collimate both mirrors with my camera, and I strongly prefer collimating directly with the intended imaging device. The end result is the end result, if you see what I mean?

At this price I may very well include it with my next purchase… A few of these might make a nice outreach set.

Will I be disappointed? Thinking about getting this EP for max 1.25" FOV in an F9 scope, although I might use it at F6 too. https://www.firstlightoptics.com/ursa-major-eyepieces/ursa-major-fmc-flatfield-eyepiece-25mm.html

I think Spocks keep on trekking, surely?

I have thought about putting a hand warmer in my eyepiece case! I think the small size of eyepiece lenses is also relevant. Even the largest ones will be quite rigid compared a big floppy newt mirror for example.

Looks great1 Very Hubble-y What do you use to stitch the panes together?

After last night's photographic collimation, I stuck in the Cheshire again at lunch time to see if it agreed with the camera. The Cheshire is saying the scope is way out of collimation... I think the issue is the focusser is not square and it is joined to the primary mirror, so the Cheshire will always give a wrong answer. However, I think the Cheshire is useful for collimating the secondary at least.

What EQ platform is that below the 12", @Mr Spock?

I think I have it close enough for a first photo. Stars are round and pointy on axis, I may need to do a few iterations to clean up the corners but I draw the line at collimating in a fine drizzle! The clouds got too thick to check the corners after tightening the locking nuts on the primary, but it was looking ok at last check.

I haven't noticed FC much with the Svbony 3-8 despite using it quite extensively. I see the appalling FC of the Nirvana 16 clearly, so we agree on that! Next time I have a clear but Moonish night I will try it out again, paying more attention to the edges. Did you see this at all focal lengths?

I have given up on the Cheshire as a collimation aid. It requires common sense and judgement, which isn’t something I’m noted for! I have switched to using my camera, and made good progress tonight. Collimation is not perfect yet but it is a lot closer than ever.

No need for a second scope for polar aligning, it can be done with the imaging scope. That's how it's done with an AsiAir after all. So all that is required is software support and a wedge. Not sure if ZWO would need to strengthen the RA wheel.

Yes I remember that Mars opposition - I travelled to the Canary islands for a better view, and Mars was completely featureless! OK, so the plan is: ES 16" dob, Geoptik EQ platform, Starsense. I'll be able to manage all components by myself if needed, and everything will be easy with an assistant. I see the ES dob is a bit tricky with balance issues, but I am not one to change eyepieces frequently (or a fan of big eyepieces) so not too worried about that.

Regretting I wasn't braver last night. I should have had a go at those collimation screws last night!

It was not a night for astronomy but stars were peeping through the complex, multi-layered clouds so I went out to test the collimation of my RC6. The collimation still has a way to go (primary screws overtightened), but I stuck in a 20 mm eyepiece and tried a few low power targets . I had quite a pleasing view of some brighter doubles like Mizar. One benefit benefit of the pinched optics was that stars were slightly defocused so star colors were accentuated. Really impressed with the purity of colors in the RC. I was using my FMA135, ASI120MM and ASIAIR as an electronic finder to zoom to a few targets and it worked really well, although of the galaxies I tried only M81/M82 were bright enough to peep through the murk. On a better night, using the AIR&co to quickly find targets will work quite well I think.

Tonight the stars were just about visible through several layers of cloud, so I could do a star test. A defocused star looked almost symmetrical, but the became triangular closer to focus. This means, i think, that I was too enthusiastic in tightening the screws on the primary mirror. I I'll back these off tomorrow and try again.

Great info, thanks @seven_legs! The scope would be set up permanently in my dobservatory, so I think I should be able to keep the mirror clean. I thought straps were the usual thing for large mirrors, to prevent pinching the optics? Can I ask how the scope performed at mags above 300x?