Quote:
Originally Posted by CosmoSat
As 8 or 9 eyepieces may seem too many for some to hve in ones inventory, one could also pick one from each magnification group still appropriately spaced.
So for a f/5 scope.. it could be
Exit pupil --- 0.6 - 1.2 - 2.4 -- 4.8 - 6.8.
Focal Length --3 - --6 - -12 - -24 - -34.
3mm can archived by using a 2X barlow the others in between by using a 1.5X one.
Clear Skies!
|
Interesting table, thanks. I like the layout.
But I liked your first range suggestion better than the second one above.
To my mind, in an f/5 dob, I'd go for
0.7 to 1mm for high power (i.e. not too hard to track an object by pushing the dob)
2mm for finding galaxies and other faint stuff.
4mm or 5mm for low power, depending on how bright one's "dark" sky is.
Which is in accord with your first range.
A 2.8 to 3mm exit pupil I find okay for the smaller open clusters in a dob, but I don't use it often unless it happens to be the lowest power I can get with a 1.25" eyepiece in a MAK. But plenty of people around here think the 3mm exit pupil is the best one to go for when viewing most DSOs.
Though definitely not for everyone, I also use an 8.8mm exit pupil with a broadband filter - mainly because I can tilt my eye withing the exit pupil beam and get rid of my eye's astigmatism without wearing glasses.
Personally, I've never found a good use for a 1.4mm or 1.5mm exit pupil, which many of my eyepieces delivered in various telescopes I've owned.
Do you use it much?
Regards,
Renato