John

I've been doing a bit of research into the feature I mention above, Reiner Gamma and it is quite fascinating. It is the best example of what is known as a lunar swirl. I came across this nice little LRO movie about this feature: https://upload.wikimedia.org/wikipedia/commons/2/24/Reiner_Gamma_vid.webm Fairly readily visible in most scopes as well

I've come in now with more cloud arriving. On the moon I finished my session with a look at the interesting pale feature Reiner Gamma which runs, or wriggles, past the crater Reiner. Very odd feature comprising of pale and darker material. Apparently it has no thickness to it and a strong magnetic field. Finished off with a pleasing split of Zeta Hercules which had risen out of the Bristol light glow into steadier sky. Nice session considering that it was raining from quite thick cloud 3 hours ago. I was using my 100mm F/9 refractor tonight but not an achromat I'm afraid. Reiner Gamma and Reiner Crater (not my image):

I have a clear spell here now as well. Seeing not quite as good as a couple of nights ago but still nice. Interesting to see how features observed two days ago with shadow in them look now they are fully illuminated. Aristarchus is blazing white tonight. The steaks of impact melt material can still be seen running up the inner walls of the crater though. Sirsalis Rille looks nice too at the edge of the Oceanus Procellarum.

Wide awake now - It's cleared earlier than predicted ! And my report is ....... it looks pretty much the same to my eye as it has for the past few nights Nice to see it again anyway.

Nice Stu It's just cleared here so I'm off out for a look myself !

Unless I doze off !!!

Solid cloud a light drizzle here so definitely no magnitude comparisons going on here tonight It's supposed to clear from around 1 am so I might get a chance then, if I feel like waiting up.

You can get thin foam foam sheets in hobby retailers that would probably have enough stiffness to make a suitable shield for a 150mm aperture. I needed to keep the top end weight down on my dob as well because of balance so I'm pleased that my half moon shield (which is an Astro Engineering one) weighs very little.

Cloudy here tonight so I doubt I'll get a peek

Good point. Must find a way to stop the uninformed having a vote

Well they are cheaper than a Tak !

I observed 3C 273 a couple of nights back: https://stargazerslounge.com/topic/374487-from-near-to-very-far-quasar-3c-273/ I did also managed to observe the outburst of the blazar CTA-102 that @Owmuchonomy mentions here: https://stargazerslounge.com/topic/374482-whats-the-furthest-away-thing-youve-imaged/?do=findComment&comment=4061446 That latter one is the most distant object that I've observed.

I have used the Baader fluid and their micro fibre cloth to clean eyepieces for the past decade with no issues at all. I use a hurricane blower to puff anything loose from the lens surface before using the fluid and only apply it via the cloth as per Baader's instructions. The fluid is applied to the cloth as a fine spray in a small patch and then using the cloth gently onto the glass so there should be no excess to get between lenses etc. That is what has worked for me. I don't use the fluid very often. Most often all I need is a few puffs with the blower, with the lens held upside down to ensure that any debris falls away from the glass.

I use something similar on my 12 inch dobsonian. Its one of the half moon shaped ones to stop light getting onto the top of the secondary and inner end of the focuser. I've found it very effective. My light issues are from one general direction. For more all around problems a tube shape would be good.

I'm no imager (really !) but I did actually manage to snap a bit of the Hadley Rille using my ancient mobile phone over the eyepiece with my 12 inch dob last year. It's not much to look at but I was quite pleased with it. I've got a better phone now so maybe I should have another go ?:

That would be my suggestion as well

I felt that as well.

I've had some short cloud gaps so I've had some nice but rather brief views of the moon including the lovely valley @Stu has pictured. Rather solid cloud cover now though so I suspect that's it for tonight

I'm getting short breaks in otherwise solid cloud here. A few minutes observing then a wait for the next gap. Better than nothing though.

Looking mixed here but I've popped a scope out in case I get a clear patch. Schroter's Valley is one of my favourites as well While doing that I watched a very bright ISS pass over, which was nice

Schroter's Valley should look lovely tonight - if it stays clear

Great report and photos Paul The views of the moon were very special last night.

Exit pupil is eyepiece focal length divided by focal ratio of scope.

I have not used all the Omni plossls but I have used quite a lot of similar quality ones. Optically they perform similarly across the the range of focal lengths. In the shorter focal lengths (10mm and less) the eye relief starts to get pretty tight. In the central area of the field of view they will be fine in an F/5 scope but the optical correction may well suffer a bit in the outer parts of the field of view. There is not a sudden focal ratio cut off where an eyepiece simply won't perform, it is a gradual thing. By correction I mean distortions to star images, mostly caused by the optical issue astigmatism which causes stars to take on an elongated "seagull" shape towards the outer parts of the field of view. At F/5 coma can also be an issue in newtonians but that is usually generated by the primary mirror of the scope. This article gives more information: http://umich.edu/~lowbrows/reflections/2007/dscobel.27.html

The slower the scope, the better the correction at the edges of the field of view will be. I presume that Celestron feel that F/6 is where the correction will be tolerable for most observers but it is still not likely to be perfect. In the centre of the field of view eyepieces generally perform pretty well regardless of scope focal ratio. At F/10 and slower these plossls will be pretty much sharp right across the field of view.