John

Thomas Back's passing was a sad loss to astronomy. Among many other things he designed the objective lens that sits in my 130mm F/9.2 triplet refractor. A really superb performer.

Are they not the same optics as the TMB Paragons ? Maybe those rumours were incorrect ? I find the 40mm pretty good for what it cost. The 30mm is OK at F/7.5 or slower. I use that mostly for outreach.

I would probably add a Rigel Quickfinder in the position I want it. It can be popped off leaving the base in place easily enough when the scope is not being used.

For me, either no filter or a good UHC such as the DGM NBP. I've used the O-III and H-Beta filters on Messier 42 to see the effects but on balance either no filtration or a UHC are my preference. I'll be interested in Don's opinion as well of course

I guess coating and polish quality have improved over recent years as well, hence lower scatter / diffraction in the latest versions ?

Saves me typing what I was about to type ! My 2 inc O-III is a Lumicon from one of their "really good" periods but there can be some variations in that brand. I have the Astronomik O-III in 1.25 inch and that is very good as well. I appreciate that it's quite a lot of £'s to spend on an item with a rather specific use though

You can put the filter on the end of the diagonal barrel or on the end of the 1.25 inch - 2 inch adapter, if it is threaded for filters. If you try the 2nd approach, make sure none of your 1.25" barrels will come into contact with the filter before attaching the filter.

No problem

The O-III makes quite a bit more impact with the Veil than a UHC does.

Do you mean the WO SWAN ?: https://www.firstlightoptics.com/william-optics-eyepieces/william-optics-swan-eyepiece.html I bought the 33mm (pre-owned) for my astro society and it works very well in their 12 inch Meade ACF LX600 F/8. When I compared it with the 30mm Aero ED in my scopes I thought they were corrected to a similar level. I've not used the 40mm SWAN though.

That's the way it was for me at the start. After a while I managed to tease out the western side and then later some of the elements in between such as Pickerings Wisp. Well done for getting that all important first sighting. You will be back for more, I'm sure

Good question. I have the 30mm and 40mm of this line and they do vary in optical performance. The 40mm is a better corrected eyepiece in scopes faster than around F/8. I've not used the 35mm so I can't comment on how that compares with the 30 and 40mm. @johninderby may well be correct on why production of a specific focal length has stopped.

I moved from the 16mm Nirvana / UWAN to the 16mm T5 Nagler and wondered why I did. Back then I was using a 10" F/4.8 dob. Never used the ES 18 / 82 although I hear that it's one of the best of the ES 82's.

I use the Aero ED 40 in my F/7.5 ED120 refractor and it's pretty much sharp right across the field of view.

Telescope Services in Germany have them but currently only seem to list the 30mm and 35mm: https://www.teleskop-express.de/shop/product_info.php/info/p2334_TS-Optics-35-mm-2--UFL-Eyepiece---69--Field-of-View---6-Element-Design.html

I have one just like that. I'm sure it is the same as the Aero ED - they have been sold under a number of different brandings. I find it an excellent "lowest, widest" eyepiece in all my scopes. It's even decently well corrected in my F/5.3 12 inch dobsonian although the exit pupil generated in that scope is rather over-large but that is not the eyepieces fault. I've been impressed by my 40mm ED SWA 2 inch. My other low / wide eyepieces are the Ethos 21 and Nagler 31 so it's in good company.

Thanks for the interesting heads up Stu. So cloudy here tonight that observing anything is pretty much impossible If there are clear skies this sort of event is worth trying to see. Locating then watching a tiny speck of light crawling along against the starry backdrop is strangely enthralling

It is excellent advice - if possible always end a session on a positive note I've observed through 20 inch scopes a few times. On one notable occasion, under dark skies, M13 and M51 were the targets. My goodness those views stayed with me for some years I can tell you The slight downside was going back to view the same objects with my 10 inch scope from home - they seemed a little "lacking" for a while It's a great experience to get even a moderate aperture scope under a really dark sky though. One year I had a 6 inch mak-newtonian at the SGL star party and had a fantastic night with my SGL friend Mark and his 6 inch newt going from galaxy, to galaxy to galaxy.

I agree with this. It might be worth having a look at the drawtube of the scope to see if a 1.25" fitting can be substituted for the .965" fitting currently in place. This would be by far the best solution. The 1.25" - .956" adaptors do take up quite a bit of focuser travel.

Great report Gerry I think being able to adapt to the conditions is a very important part of creating an enjoyable session. Until you put your eye to the eyepiece you never quite know what the conditions will serve up - having a plan B and being able to move over to that is much better than banging away on targets that will not be seen too well.

I'll be using the 1.25 inch filters I currently have: Meade 4000 Nebular UHC type and an Astronomik O-III. I do have an H-Beta in 1.25" as well but I doubt that will be effective with the binoculars

Tele Vue designed the 40mm version of their plossl expressly for glasses wearers I believe. To some extent I feel that the Explore Scientific 92 degree eyepieces favour the glasses wearer, especially the 12mm.

Thank you all ! My 11x70's plus the two filters will be taken to dark skies in Wales shortly and, clouds allowing, I'll be able to "see for myself"

Binoculars are often the best way to see Mercury. Nothing fancy, 10x50's will do it just fine. I don't know how often it can be done but one of my society members did it a few weeks ago.

I wonder if the primary mirror could be shimmed slightly to improve the collimation ?