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View Full Version here: : Best eyepiece for 8" dob


gel
16-07-2008, 05:42 PM
mainly for planets ,i like 8,10,12 but so far all i have used is plossels,what would you recommend considering its tax time and the aussie dollar is good.
do i go for a $200-$300 price range,name the product?,name the size?what would be the overall difference from a plossel!

wavelandscott
16-07-2008, 06:11 PM
You might get more responses in the Eyepiece thread but I'll start...

First, check out the Televue website and the article about choosing eyepeices for a small dobsonian...it is a good and helpful read.

I'd recommend shooting for an exit pupil of 1.5 -2 ( The eyepiece exit pupil diameter is found by dividing the eyepiece focal length by the telescope focal ratio)...that is the "sweet spot" for me and my viewing habits....although other people may want to use even more magnification

Although I am not certain of their current price level, I'd highly recommend the Pentax XW (7 or 10 mm) line of eyepeices...two of my favorite eyepieces. I hear that the 5 and 3.5 mm are also very well regarded if you want even more magnification.

They will differ from the plossl eyepeices in these areas:
*wider field of view
*more eye relief
*physically larger
*more expensive
*may or may not have "better" coatings

If the Pentax XW are out of your price range, the BO/TMB Planetary Eyepeices (available at Frontier Optics) I think are a good value for money choice and have a few myself.

Other people will speak highly of some of the other Pentax lines...

Another alternative would be to invest in a high quality barlow or Powermate to use with some of your other exisiting plossls to increase your magnification...

My last piece of advice is to get out with some other astro hobbyists and try out some different eyepeices before you spend your own hard earned money. If you are not a member of an astro club or society I'd encourage you to join one and/or seek out others in your area for an evening of viewing...almost everyone I've met in this hobby have been happy to let me sneak a peak through their gear and even on occassion use some of theirs in mine (and reverse)...it is a great way to learn about some of the otehr gear available and also learn more about what you like and don't like.

Good Luck and Clear Skies!

CoombellKid
16-07-2008, 07:08 PM
For the money your looking at spending check out this thread.

http://www.iceinspace.com.au/forum/showthread.php?t=33873

I'd be looking at the 7mm or 14mm Pentax XL's, since you have a 2x barlow
the 14mm would probably be best, it'll give you a medium powered DSO
(I know you have mentioned your a planetary guy) but barlowed it will
give you the equivilent 7mm XL, which would be ok for planetary.

In my 8" I use XW's planets, but my most used ep would probably be my
20mm t5

regards,CS