globular

Interesting idea. Please do let us know the results of your trial. @Second Time Around I know you are a dioptrx expert - do you know if they would work earlier in the light path, or do they have to be close to the eye for proper correction?

I've been 'breaking my dark adaptation' when viewing planets and the moon for a good while. I find there are clear benefits of doing this on the moon and with no downside. With the planets it seems to me that some surface details are better without dark adaption and others are better with it.... so I try and do a bit of both. Nice to hear there is some science behind it.

If there aren't too many distortions produced within the eyepiece then the following formula works well: field stop 180 ------------- x ----- = FOV focal length π

oooo precious

So sorry this has happened. I'm quite shaken just from reading your account. Thanks for sharing and keep us posted with your replacement(s).

I'd imagine it's similar to the CPC version in this thread? https://stargazerslounge.com/topic/315553-cracked-celestron-cpc-tripod-leg-clamps/

どういたしまして、ジェレミー (Thank you Google-san)

Celestron do one, but it's a single thumb screw affair https://www.rothervalleyoptics.co.uk/celestron-visual-back-125.html William Optics do a better "rotolock" one, but its more expensive https://www.rothervalleyoptics.co.uk/william-optics-125-sct-rotolock-visual-back-adaptor.html I prefer a Baader three screw compression T2 to 1.25" (connected with a SCT to T2... the bresser one is a good value option (and you get some M42 extensions for free)) https://www.firstlightoptics.com/adapters/baader-ultrashort-1-t-2-eyepiece-clamp.html https://www.harrisontelescopes.co.uk/acatalog/bresser-sct-adapter.html

Have you managed to do this yet? If not then 1. both of the prongs on the removal tool should be inserted into the two holes on coupling 2. press the tool towards the binoviewer... keeping the prongs engaged is more important than anything else 3. keeping inward pressure, add an anti-clockwise twist. Not too hard and jerky... smooth and continuous pressure is the key. Good luck.

Wow!

Did you ever cut a slot with scissors, to mirror the one already there, to turn them into double sided? Happy days.

I thought Jeremy handles Takahashis 🤔 😄

Hi @FLO A few years have passed and I can't see this EP on your website these days... but can you still get them? I'm thinking about a pair of them for binoviewing. There don't seem to be many options at 28mm with long eye relief. 🤔

@Don Pensack Do you have a link to a -12.7mm one? Or a maker?

Be aware in your calculations that the 1.7 GPC is actually more like 1.4x (when used as directed in the bino nose). (The 1.25 and 2.6 are closer to their specified mag factors; 1.2 and 2.5 resp.)

That's the fella. Hop and a skip from M80, a nice globular.

They are in Skysafari under SHJ 225 and SHJ 226. I think SHJ is the catalogue designation of James South (1785-1867).

I dictate into voice notes on my phone while I'm at the eyepiece. Then write them up the next day. When you play it back you can do it at increased speed and get it to miss out the gaps.. so it's pretty quick to do. I find it leaves much more time to observe... when I used to make paper notes I lost a lot of observing time and/or often didn't bother taking notes at all.

I've just spent a good while trying to spot it... with no joy. I've mapped out all the background stars in that location and can account for everything I can see and so I'm pretty sure I know exactly where it is.... but I just can't pick it out. Was fun trying though... just need a bit darker skies I think.

My notes for the ring nebula a few weeks ago say the same thing... "WOW it's so big tonight... I'm sure I can see some structure and blueness in the centre... or am I being influenced by images I've seen.... I don't think so..."

Yeah I reckon I'll probably end up trying a pair or two of them to get me started... but the eye relief does worry me.... 16mm claimed is already tight... and I've seen reports they're only 13-15mm in reality.... And although they are pretty good in the centre I might not like the views at the edge.... so maybe the extra FOV will be more off putting and should get a 50° set after all..... Like I say... circles.... 🤪

Possibly. I'm struggling to convince myself to go for 50° EPs ... I'm looking for 60° ideally. But I'm going round in circles at the moment. 🤪

Agreed. I've measured my Hyperflex 7.2-21.5 as 38.3° @ 21.5mm and 56.5° @ 7.2mm.... as opposed to the claimed 40°-60°. I haven't measured the eye relief.... but the claimed 15mm might be a but optimistic too. Not bad views though generally. I've kept mine for the same use as you.... to test the water before moving to better and wider fixed fl EPs. I'm looking again at zooms as I have a new pair of binoviewers.... but I'm not sure I'm going to succeed in my hunt and will instead end up with some cheapish fixed EP pairs....