The joys of a small 'richest field' scope

[RobertI]

Last night was a beauftiful crisp clear night but I just didn't have the energy to go out and observe. As I dragged myself to bed I felt the need for a quick fix so I grabbed the finder scope from my grab and go setup, leaned out if the bathroom window, and had a browse! The scope is a 60mm F3.75 Altair Astro  achro RACI finder with a 21mm Hyperion eyepiece giving a FOV of around 6 degrees and a magnification of around 11x. The wide star rich views were simply superb and I ended up spending about 30 minutes scanning around the sky. Ok the distortion towards the edges of the field were quite severe but this did not detract from the viewing. The light weight of the scope meant it was easy to hold (no mount needed) and the diagonal meant viewing at the zenth was a doddle and much easier than using binoculars. I think this setup probably qualifies as a 'richest field' scope which, I believe, is a scope whose purpose is to show the maximum number stars possible in the field of view. All  the old favourites were easily found with the highlight being, unexpectedly, the Hyades, which filled the field of view with bright stars with the orange Aldeberan providing a lovely contrast. M35, M36 and M37 were very prominent overhead and provided plenty to explore. The Pleiades were surpisingly small with this setup and possibly would have been better with more magnification and M42 needed more aperture but was still a nice sight. There were many open clusters visible which I did not have the time to identify, but it was great fun and immensely rewarding just scanning the starfields whilst my lower half remained indoors and toasty warm.  

 

[Chris]

Nice one Rob  It's amazing how a quick peak can turn into 30 minutes before you know it! I reckon any TV EP would be good with this finder, probably the only EP's that can hack f/3.75.

[geordie85]

I quite often grab the finder scope from my 200p to scan the heavens whilst my star 71 and ccd are doing their thing. 

May need to look into seeing if there is a focuser I could get for it to accept eyepiece's. 

[RobertI]

2 hours ago, Chris Lock said:

Nice one Rob  It's amazing how a quick peak can turn into 30 minutes before you know it! I reckon any TV EP would be good with this finder, probably the only EP's that can hack f/3.75.

Good thought Chris, I assumed it was the deficiency of the cheap achro lens which was to blame. When I finally get to my improved back garden observing site, I would love to treat myself to a TV eyepiece, just not sure the rest of my kit is up to it!  

1 hour ago, geordie85 said:

I quite often grab the finder scope from my 200p to scan the heavens whilst my star 71 and ccd are doing their thing. 

May need to look into seeing if there is a focuser I could get for it to accept eyepiece's. 

Yes, finders are pretty cool mini-scopes for wide field viewing. I also have a Explore Scientific 8x50 straight through finder which is a lovely thing. No interchangeable eyepiece but I suspect it is optimised for maximising number of stars visible - I think an exit pupil of between 5 - 7mm is ideal from what I have read so any eyepiece chosen for wide field viewing should aim to give that (correct me if I'm wrong, which I frequently am!)