What's your scope?

Thanks for the tips and useful links guys.
I just prefer the 2" EP's on the dob even though it has an adaptor.
I have used 17mm Nagler Type 4( borrowed from MOC), which is brilliant, but the price is crazy.
With the usual bad seeing we have, what would be the power mag limit for lunar/planetary observing with a 12" f/5 dob : .
From what I have noticed, around 200X is the max power I can get, but maybe I am doing something wrong.:oops:
Some 2" EP's go "up to" 2.5mm which I think is unrealistic for what I have.
Johnno
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Dobsonian 12" F/5
ETX-125EC
10x50 Bresser bino's

John,
On most nights 200x is close enough to the limit of what is a useful magnification. Sure, there will be nights when you can increase the magnification substantially, but they will be few and far between. This is simply due to the turbulence in the atmosphere. If shopping for a good quality planetery eyepiece, I'd aim for one that gives roughly 200x magnification, which in your case roughly 7-8mm.
As for the cost of the eyepieces, you'll only every need about 3 of them. If you get good quality ones, chances are you'll still have them and use them in 10 years time. However, I do appreciate that they are expensive.
Clear skies,

www.siebertoptics.com/SiebertOptics-1.25in-eyepieces-ultra.html

Michael, what do you think of these 2" EP's, especially the 7mm one ?

Johnno

Difficult to say to be honest. It seems to have everything going for it; it's got a decent AFOV of 70degrees, they've also got good eye relief which is important when wearing glasses and have 6 lenses which might be a sign that they work well in fast scopes by compensating for the angle of the light from the primary mirror.
However, you never really know until you look through one. For the price though, I don't think they could be bad. I've heard alot of good reports about Siebert Optics in general recently. There's certainly a few people on cloudynights.com who sing their praises. FWIW, they're also the only company that I know of who manufacturer a binoviewer to take 2" eyepieces.
There's only one way to find out!

Thanks for that Michael. Tele Vue website very useful..........especially Pop UP Eyepiece Calculator. Would be nice to have 2" Nagler 5........... 31mm & 20mm. Must go check out the prices :!:

Prepare yourself for a shock, especially when you see the price of the 31mm! ($620)
Clear skies,