dawson Posted February 24, 2013 Share Posted February 24, 2013 Does the field of view for any given lens vary much between telescopes? My 25mm lens which came with the scope is my widest view lens, but might view be even wider in someone else's telescope? If so, how does one know what the widest possible field of view is for any given telescope? Skywatcher 127 Regards James Link to comment Share on other sites More sharing options...
Guest Kheldar Posted February 24, 2013 Share Posted February 24, 2013 Depends on how many numbers you want to crunch here, and one 25mm EP is not the same as another 25mm EP ... factors to consider are FOV of the EP itself, magnification and focal length of the scope which in turn alter the true FOV you are seeing, then there is exit pupil of the EP and how much of that light you can actually see ... not to mention restriction on FOV based on the focuser draw tube .... I'm no visual expert, but it's a big question I think Here's a couple formula to get started Magnification = Scope Focal Length / Eyepiece Focal Length True FOV = Eyepiece Actual FOV / MAG Link to comment Share on other sites More sharing options...
dawson Posted February 24, 2013 Author Share Posted February 24, 2013 Telescope focal length = 1500 (f/11) Mag; 1500 / 25 = 60x Mag; 1500 / 10 = 150x I'll have to research what the EPs FOVs are. Thanks. James Link to comment Share on other sites More sharing options...
Guest Kheldar Posted February 24, 2013 Share Posted February 24, 2013 Stock SW will be about 50deg Link to comment Share on other sites More sharing options...
dawson Posted February 25, 2013 Author Share Posted February 25, 2013 Will upgrading my EPs, Barlow and star diagonal make much difference to my viewing experience with my 127mm Mak-Cassegrain, or would it e much more noticeable if I had a bigger telescope? I tend to use the star diagonal all the time. The many different makes of EPs make it all very confusing. Is there somewhere where the various EPs are ranked in some kind of order (and price) to demystify this? THanks James Link to comment Share on other sites More sharing options...
Guest Kheldar Posted February 25, 2013 Share Posted February 25, 2013 (edited) Will upgrading my EPs, Barlow and star diagonal make much difference to my viewing experience with my 127mm Mak-Cassegrain, or would it e much more noticeable if I had a bigger telescope? I tend to use the star diagonal all the time. The many different makes of EPs make it all very confusing. Is there somewhere where the various EPs are ranked in some kind of order (and price) to demystify this? THanks James Well to be blunt about it, an SCT (I think that's what you have) is not a wide field scope anyway due to it's long focal length. You can stick something ridiculously expensive in there like a 100deg EP and your FOV will still be poor compared to a Newt or refractor with a short focal length. However upgrading EPs from the stock ones will be a benefit regardless in the quality of image. Upgrading the diagonal almost certainly will improve this. A long focal length / ratio scope is VERY forgiving of EPs, you don't have to spend the Earth I would suggest. Again, I'm not visual any more so I'm going to comment further there There are general concencus as to which EPs are better than other, but EPs are a very individual thing. If you can have a look through someone elses first then you will reap benefits from not wasting money on EPs that may not suit you. Edited February 25, 2013 by Kheldar Link to comment Share on other sites More sharing options...
dawson Posted February 25, 2013 Author Share Posted February 25, 2013 That's useful, thanks. James Link to comment Share on other sites More sharing options...
Teslar Posted February 25, 2013 Share Posted February 25, 2013 (edited) Your Mak is better for Planets and specifically (given you have a small Mak) the moon and will take higher magnification so you can use a high power Barlow to get very detailed viewing or photos of moon craters etc. using a high mag Barlow will increase your focal length and make for a small FoV but you will be rewarded with very detailed views when seeing allows Edited February 25, 2013 by Teslar Link to comment Share on other sites More sharing options...
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