Quote:
Originally Posted by Graman
Questions/advice sought:
1. Given that my 2 inch EPs and barlow pretty much covers everything from 9 mm onwards, do I still need 1.25 EPs in the 9 to 18mm focal length range? What additional advantage do they bring? Is it more clarity/brightness because there is no barlow involved? Would it make a difference in dark sites? What will I gain from squinting through a small 1.25mm lens barrel instead of the more comfortable 2 inch barrel? Can someone enlighten me on the pros/cons?
2. If 1.25 inch EPs do offer benefits, what focal lengths should I be looking at to suit my SCT?
3. What about getting a good quality zoom instead of getting 2 or 3 individual 1.25 inch EPs? While Leica or Zeiss are out of my price range, would Baader or Swarovski zooms be comparable? Part of me likes the idea of popping a zoom with a 2-inch adapter into the diagonal and not have to mess with EP changes in the sub-18mm focal length. What are the pros/cons of this approach?
Any advice much appreciated. Thanks in advance and clear skies!
It looks like it will be a cracker in Sydney for the next week or so - hope it continues for the Lunar Eclipse end of the month - finger crossed.
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1. Eyepiece barrel size is dictated by the eyepiece designs field stop. Generally speaking the most comfortable eyepieces to look through are actually 1.25" eyepieces. Pentax XW, Televue Delos, Baader Morpheus all have 20mm of eye relief and are about as comfortable to look through you could possibly find, they are also some of the sharpest.
2. The only reason 1.25" would provide an immediate benefit is - lighter weight vs 2". Also - accessory costs are cheaper. High quality diagonals, filters, and barlow lenses are cheaper with 1.25" format. Judging by your current set of eyepieces I would consider higher power eyepieces. 14mm and less. Pentax, Televue, Baader all have an excellent selection of sharp comfortable eyepieces from 14 and below.
3. keep in mind zoom eyepieces are a series of compromises for unmatched convenience. Current designs means when moving though the focal length settings the field of view changes. Example - Nothing wrong with the Baader Hyperion Zoom 8-24mm, but its field of view goes from ~68 degrees to 50 when moving from 8mm to 24mm. There's also compromises on sharpness at some settings. Most Zooms perform best at their higher magnification settings and soften at the lower magnifications. That being said, the Baader 8-24 is very usable in your 8" scope. In works well in all my telescopes. I do use a coma corrector for the fast Newtonian's though. You don't have that issue with your current setup.
Keep your ear to the ground though. APM are releasing a new zoom eyepiece in June - and its going to be an absolute ripper. I know its going to end up in my case.
