John

Great photo - a classic "backyard astronomy in action" shot

If eyepieces get really cold, even the heat from your eyeball can cause them to fog / mist up. Eyepieces with long eye relief and deep eyecups are more resistant to this - the Pentax XW's do quite well for example.

Still quite nice conditions here. Tegmine / Zeta Cancri split well at 300x and 400x with the 130mm refractor. Sirius B showing quite nicely as well at 240x. Dubhe seemed to have a "bulge" on the side of it's airy disk at around the position that it's secondary star is but not a split in any proper sense. Getting a bit chilly now so I won't be out for much longer.

Interesting comparison. The Starbase 80 is clearly a very good achromat

I am very pleased that you like the scope Mark It was a pleasure meeting you today, chatting about scopes and observing and seeing your "monster in the shed"

As a visual astronomer I thought the Tele Vue 102 F/8.6 was a very tempting telescope. They discontinued it however back in 2012

My first target with the 130mm refractor tonight was 7 Tauri, inspired by @Nik271's post here: Good result from the 5.1 inch refractor I thought. Tough way to start a session though

Had a crack at 7 Tauri with my 130mm refractor just now. At 300x - 400x I got the bright pair of stars as a clear "∞" or "peanut" or "snowman" or "waisted pair" form with just a few tantalising suggestions of the actual split from time to time during the moments of steady seeing. The 10th magnitude star further away was quite easy to see. Thanks for the "heads up" on this one Nik. Well worth seeking out

Not dark yet, but it will be soon

I get similar results with these two with my 100mm Tak as well. Close but no cigar on 52. The ED120 got it a couple of nights ago though - that little bit more aperture tips the balance. Good pair of Winter test doubles these 😀

Here is another good article: https://skyandtelescope.org/observing/sirius-b-a-new-pup-in-my-life/

I've tried filters and occulting bars over the past decade but eventually found that good seeing, lots of trying and around 260x with a low light scatter eyepiece eventually enabled me to spot the Pup star glimmering, on and off, faintly through the glare halo from Sirus. That glare can often extend outward from Sirius A for 20 arc seconds of more so, with an 11 arc second split, the Pup star has to be spotted through that. I would never call it an easy target though even after having observed it quite often over a few years. It's a very hard thing to see IMHO, even with the wider split today than when I first went for it. It's worth doing a sketch so that you can check the position angle and other field star positions, just to be sure. This is an excellent article on spotting Sirius B and seems to match with the experiences that I have had trying to do it: https://earthsky.org/brightest-stars/how-to-observe-sirius-b/

That is a really amazing result on Sirius 😀 I've never been able to get the split with less than 225x and much more usually 250x - 280x is required even with my 12 inch dobsonian. I've found filters simply reduce the glimmer of the Pup star to the point where it no longer shines through the glare from Sirius A. Your SCT must be in really excellent shape and your skies (and eye) right on the nail tonight - congratulations !

With fine features such as rilles and craterlets, the lunar illumination can be critical in determining what you see and the extent of it. Sometimes the optimum time window is just a few hours during which the solar illumination falls favourably. Add to that the need for steady seeing to pick up the finer details and it's clear why sometimes things just don't quite work out. At least with the moon, if you don't get it this time, there is always another chance in just under a month.

Looks great here but I'm having an evening off Enjoy the views, all those that are out there !

I have the 5mm Pentax XW and it's one of my most used and favourite higher power eyepieces I feel similarly regarding the 3.5mm, 7mm and 10mm XW's, which I also have

Sorry - I missed your question. The map is an extract of the ones that Nik mentions above, that I picked up online. I mostly use the 21st Century Atlas of the Moon by Wood and Collins plus the freeware Virtual Moon Atlas plus a couple of free Android apps.

In the past I've seen that central rille in the Vallis Alpes with my 12 inch dobsonian. I seem to recall that the Pentax XW 5mm was a "goldilocks" eyepiece for that task. Higher or lower magnifications seemed to make it more elusive. The same scope and eyepiece showed me 11 Plato craterlets on one memorable night, best I've ever done Not sure that I've seen it for sure with any of my other scopes I probably should have had the 12 inch out last night but initially the conditions looked a bit dodgy so I stuck out the refractor.

Nothing exotic for me tonight - the good old ED120 + Skytee II workhorse. It did a fine job, performing very close to the theoretical limits of the aperture. Can't ask for more

I'm getting a bit cold out there so I'm drawing things to a close tonight with Sirius (and the Pup glimpsed a few times) and Tegmine / Zeta Cancri the close pair of which the 120mm split with a little more ease than my 100mm did last night. The seeing is still very good - even a rather stupid 450x gave decently defined views of these 3 pale yellow stars. The split between the close pair is 1.1 arc seconds so quite tight.

A couple of 2 inch parfocal rings might work: https://www.firstlightoptics.com/adapters/astro-essentials-parfocal-rings.html

I've seen the Hadley rille with my 100mm refractor. Tonight some sections of it were clear with my 120mm. I snapped an image of it a while back with my mobile phone at the eyepiece of my 12 inch dobsonian. Not the best clarity but at least the rille can be seen !

Still wonderful seeing here I've just had one of the best views of 52 Orionis that I can recall from the ED120 refractor. I'm getting a clear but very fine dark line between the two airy disks about 80% of the time. According to Stella Doppie the separation is currently .99 of an arc second so close to the limit for the aperture. The moon is just so sharp as well.

Nice report and sketch The seeing tonight is really excellent - fine features on the moon (eg: Hadley Rille) are standing out as well as I've seen them for quite a while.

A friend at Bristol AS (Chris) has pointed out that the feature known as "Thor's Hammer" is nicely on display as well tonight. And he is right ! Worth a look while enjoying the mare Imbrium, it is near Mount Piton (not my photo):