John

You can tilt the focuser and objective cell by shimming with tape but having proper collimation adjustment makes life easier.

Sounds like M31 to me. The eliptical fuzzy core is what we see unless the skies are really dark and transparent in which case it is possible to trace the galaxy further out from the core. In a low power field of view you should also see the small condensed fuzzy satellite galaxy of M32 and a little further out on the other side of M31, the much fainter small oval smudge of M110. Worth looking for when you next have a go at this object Messier 81 and 82 in Ursa Major are well worth checking out as well.

Good stuff Jon ! Many of the lower cost refractors that I've owned have required colimation to some degree. I use a 2 stage process: focuser optical axis first (laser colimator for this) and once I'm happy with that, the tilt of the objective with the cheshire as you have done. Hopefully you will see some benefits in the views in due course

I've got an FC100-DL (F/9) and it is very happy indeed on the Vixen GP which I think the EQ5 is cloned from. I've added a Vixen style DT bar to the Tak clamp:

For visual astronomy, a good FPL-53 based doublet 102mm aperture refractor of around F/7 is a very versatile scope and relatively easy to mount and cart around. My Vixen ED102SS is mine (F/6.5 actually) and can range from a 4 degree true field for really large DSO's to a sharp 200x - 250x on the moon, planets and double stars. An AZ-4 mount will hold it well. Not sure that an F/11 (of whatever glass type) would be able to do all that

Agreed - gentle scope tapping or wobbling is a good way to reveal a faint surface brightness target.

I put one of the Skywatcher 1.25" dielectric diagonals on the Mak 90 that I had. That worked well: https://www.firstlightoptics.com/diagonals/SWdiagonal-20967.html or in StellaMira branding: https://www.firstlightoptics.com/diagonals/stellamira-1-25-90-di-electric-diagonal.html With a max AFoV 1.25 inch eyepiece I could get approx 1.3 degrees (minus any vignetting) which is about as much as I could hope for from a scope which is never going to be a wide field instrument.

Excellent sketches Mark I was observing on and off (in tune with the cloud cover !) with my 12 inch dob last night and saw similar details for a while, which you have captured excellently. Those dark "promontories" sticking out into the paler areas were rather nice features last night. As you found, the seeing took a dive later and the surface features became much vaguer. I wondered if the south polar cap was actually a little larger last night than the last time I observed Mars ?

Tonight was a bit frustrating here as well. I put my 12 inch dob out before supper under a clear sky. By the time I had finished eating we were heavily clouded and it even looked like rain, so the scope came back in. Then the cloud broke up and some clear patches arrived but it still looked dodgy so I used a lightweight refractor to peek in the gaps. Then more cloud so that scope came in. At 10:30 a larger clear spell seemed to have settled in so out went the 12 inch again. 30 minutes later I made the SN observations noted above, had some nice views of Mars and Uranus and then, more clouds piled in In, out, in out, just like the hokey cokey !

Rather poorer transparency tonight but I have managed to see SN 2020uxz again. Using the 12 inch dob at 265x I can't get mag 14 or fainter stars due to a slightly milky sky. The SN is showing faintly where it did on the previous observation - I'd estimate around magnitude 13.5 perhaps ?. It is dimmer than a nearby mag 12.8 star but a touch easier to see than a mag 13.8 star that is mostly visible only with averted vision tonight. No sign at all of NGC 514 !

Apologies to @Captain Magenta / Magnus for diverting this thread onto my particular issues. Thanks again for your interesting report

Fair point but up until now I was really delighted with the 100 degree Ethos's in my F/5.3 scope. Come to think of it, nothing has actually changed with either the scope, the eyepieces or me so I guess I'll go on being happy with them

Well, it was clear when I put the scope out before supper. Now solid cloud and looking like rain at any minute. Just bought the gear back in Silly hobby !

9x50 RACI optical and Rigel Quikfinder for me. Telrad would be fine instead but I wanted something lighter. RDF's are OK but the defined diameter circles of the Rigel and Telrad can really help with star hopping.

Thanks Don. Rather depressing though

When I had a 90mm mak recently I tried both the stock RDF and a 6x30 RACI optical finder (separately) on the scope. The optical finder was more effective (plus they are a more regular tool for me) but I felt that it didn't go with the very portable / compact scope package that I was after so I got on and used the RDF making sure that it was well aligned with the scope optics and managed OK with it. I don't actually have a straight through optical finder of any sort now because I much prefer RACI's.

It's somewhere between FPL-51 and FPL-53 in terms of potential for CA control but remember that the glass used in the mating element plus the figure and polish of the lenses is equally important.

So why am I not noticing coma ? I've been using Ethos eyepieces with this scope for over 5 years now. Without coma correction. I guess I thought I was a reasonably good observer. I'm beginning to wonder now .......

Generally, the lowest power eyepiece that I use with my 300mm F/5.3 Orion Optics dob is my 21mm Ethos. The field stop on that is 36.2mm.

@Dantooine has very kindly loaned me an Antares 1.6x barlow to try out

Well it might be there but at a level which does not intrude, for me at least. I've often let targets like Saturn and double stars drift right to the field stop and the detail seems to stay sharp right until the object disappears behind the field stop edge.

Sounds good to me ! Nothing but clouds here for the past few nights. I could do with a short non-technical stargaze I've got a nice barlow to try out ....

Mine is an OO 300mm with a focal length of 1590mm so F/5.3. I'm sure there is still coma present of course but at lower levels than at F/4.9. That said, I used to own an OO 250mm F/4.8 and happily used Naglers without a coma corrector in that scope so perhaps I'm not particularly sensitive to coma ?. I don't like astigmatism though.

The past week or so have been poor but over the last few months I've managed to do plenty of observing. It has been one of the better things about what has otherwise been a very challenging period as we all know. I don't image though and I've kept my setups to those which are simple, quick to deploy and tear down. That seems to have helped to capitalize on the clear skies when they have been around. If I had to setup complex gear each time I wanted to participate then I think it would be a much more frustrating hobby ! Edit: I've just realised that this thread was in the imaging section so please ignore my post - it's not really relevant.

Very interesting report - thanks for posting it It is interesting to note the differences in coma between an F/4.9 newtonian and an F/5.3 (which I have). I guess there will be some present at F/5.3 but even with my 100 degree AFoV eyepieces I don't find that it is noticeable. Good to know that the Paracorr will do the job if I do start to notice it