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Planetary eyepieces?
Ok.. it's getting close to decision time..
I'm going to use IISAC to compare many different types of planetary eyepieces.. with Saturn at opposition and Jupiter rising late, it's be good planet viewing conditions (hopefully!)
My scope is a 10" dob (1250mm FL), and I generally use an EQ platform. So wide FOV isn't a necessity.
I currently own a 9mm GSO plossl that came with the scope. The magnification of 9mm (@ 138x) is ok when the seeing is less than average, but I want something higher mag for when the seeing is "good" and again when the seeing is "great".
A 5mm will give me 250x, a 6mm will give me 208x and a 7mm will give me 178x.
I'm looking for something in that range, perhaps a 5mm and a 7mm. Depends on the style, type and price.
I'll also be getting a 2x barlow (at some stage (I sold my 2x GSO barlow)) to use on this eyepiece when the seeing is great.
For the last 2 months or so, i've had on loan a Tak LE 7.5mm (thanks Louie!) which I've been using as my planetary eyepiece. I find it very comfortable to use, 10mm ER, 52° AFOV, sharp to about 90% and good contrast. They could be picked up for under AU$200.
At the last Kulnura meet, I had a brief chance to try John B's 7mm UO HD Ortho, and compare it to the Tak LE. Unfortunately the seeing was not good and Mars was but a small blurry mess, so it was difficult to draw any conclusions. I tried it on the trap on M42 as well. During the short 1 hour comparison, I could not draw any conclusions as to which was better - both revealed the same detail, had very similar colour reproduction and were sharp with equal contrast. more testing is needed, but at that time, there wasn't a standout. The UO HD Orthos have a 45° AFOV, much tighter ER (probably around 5mm) and cost less as AU$125 brand new.
The Tak LE was slightly more comfortable to use, thanks to the larger eye lens and longer eye relief. But I don't wear glasses so the Ortho was still easy enough for me.
Others in the equation:
- Televue Plossl
- Vixen LV
and then premium widefield (probably overpriced for a planetary EP)
- Pentax 7mm XW
- Nagler 7mm T6
- Vixen 7mm LVW
For the price of a premium widefield, I could get 2 UO HD orthos (5mm and 7mm), and probably a 2x barlow as well! So it'd take some convincing for me to rank a premium widefield higher.
Your thoughts and experiences on any of the eyepieces above? Feel free to throw anything else into the equation.
My budget is around $300, which pretty much rules out the premiums, but if I determine (through my own viewing at IISAC) that a premium is soooo much better than an Ortho or other cheaper plossl then I'll just save up a bit longer to extend the budget.
Thanks
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