Your Largest Purposeful Exit Pupil

[scarp15]

11 hours ago, jetstream said:

I was just using the 30 ES 82 at f4.1 with great results, this gives about 7.3mm exit pupil. The Crescent neb showed really nice fine structure with it and a UHC or OIII. I observed no ill effects with it and it gave VG low power DSO views.

 

Very interesting Gerry. I will be considering a 41mm Panoptic for this winter. It might be too much with my VX14 at f5.3 applied to using a Paracorr; 7.7mm exit pupil, yet would be inclined to try this if circumstances are applicable. There is an experienced observer (whom I understand is in his late sixties, early seventies) on Cloudy Nights, who reports using an 8mm exit pupil to assist when observing Barnard's Loop.  

Edit: For H-beta observing, accepting stopped down aperture

1 hour ago, jetstream said:

After using the 2499mm fl scope at f4.1 it appears to be very flexible in many regards. It seems that I can use large exit pupils without diminishing some DSO's views, in part because the focal length gives enough image size so there is no degraded views at low power. In the 15" some objects can become small enough to impair views at this level...

Up until now I thought the effect was due to the increase in exit pupil, but now believe object size (eyepiece) plays a role.

Blackwell etc al apply this effect to thresh hold objects- I think visual object size also has an effect in other circumstances. Just a thought...

More to digest, thanks.

Edited September 24, 2019 by scarp15