good eyepieces for f/10 dobsonian telescope?

[Robstargazer15]

Im confused with what eyepieces i can use with my 12'' zhumell telescope. Im thinking about buying some new eyepieces. I need a large FOV that doesnt shrink when you add magnification. The field then gets fuzzy and wont focus with the eyepieces i have. I need some options because i dont know which ones to buy.

[Capricorn]

Are you sure it is f/10 ?

Sounds wrong.

If the magnification increases the field of view decreases. Even going to the 80 degree eyepieces doesn't really do much, so not a lot that you can do.

Apparent field of view = (Eyepiece filed of view) / (magnification)

So double your magnification and you get half the field of view.

Tempted to say go buy the Astro Tech Paradigms from Astronomics, just need more about the scope.

Wonder if the scope needs collimating as a fuzzy view sounds as if something is wrong, as does not coming to focus.

[John]

The only Zhumell 12" dobsonians I know of are F/5 - the focal length is 1,500mm or therabouts.

Useful low magnification / wide field eyepiece would be a 2" fitting 30mm.

At the other end, a 1.25" 6mm eyepiece would give you 250x which is as much as is usable most of the time.

In between those something around 9mm and something around 16mm would be useful for the medium magnification range.

Brands / Prices vary from $40 to $800 per eyepiece so name your budget !

[Joseki]

The Zhumell 12" Dobsonian is f4.93 isn't it?

http://www.zhumell.com/telescopes/dobsonian/z12-dobsonian-telescope/

[JamesF]

You'd need a cherry-picker to get to the eyepiece of an f/10 12"

James

[JamesF]

If it's an f/4.93 then it's not going to be particularly tolerant of cheap eyepieces, especially if you want a wide field of view. I think you'd be looking at the Explore Scientific ES80 and ES100 range, the Meade 5000 UWA range and Tele Vue Naglers and up.

Are there any other eyepieces with a wide field of view that are happy at that sort of focal ratio?

James

[John]

....Are there any other eyepieces with a wide field of view that are happy at that sort of focal ratio?.....

William Optics UWAN's / Skywatcher Nirvana's are pretty close to Naglers even at F/5-ish.