Have I made a mistake

[John]

But if you want a planetary EP then you don't need a wide field of view, surely?

Useful with a manually driven alt-az scope like a dobsonian. Tracking objects at high magnifications is easier when you have a wide field of view to play with, eg: a Nirvana is showing twice as much sky than an orthoscopic. You do want it sharp though and that can cost in a fast scope.

[cotterless45]

I use a 21mm Hyperion and a 10mm in f5 and f6 Dobs.I use these fairly wide field fov for deep sky.

For planets I use just a basic super plossl 10mm and 6mm.

Planets are not always available and need fairly high magnification and tracking to get the most of of a manual Dob.For me planets are just a sideline to the deep sky show.You'll also be needing the very best of seeing conditions.

At high mag, you might consider getting your collimation spot on with a Cheshire and checking it with a laser inserted in a Barlow in the focusser.This'll give you the reflection of your primary central ring , which you can centre using the primary adjusters.

Spot on collimation will make any Newt a planetary killer,it really does make a difference.

Nick.

[faulksy]

due to you being quite local to me we can arrange going out if you want and you can try some of my e.p.s just a thought

[x6gas]

Useful with a manually driven alt-az scope like a dobsonian. Tracking objects at high magnifications is easier when you have a wide field of view to play with, eg: a Nirvana is showing twice as much sky than an orthoscopic. You do want it sharp though and that can cost in a fast scope.

Ah - good point, thanks.

[umadog]

No, you don't need a wide-field eyepiece for viewing planets. But if most of the field is riddled with astigmatism then you're going to have to be pushing the scope more often in order to maintain the planet in the sweet spot. It will look rubbish once it drifts into the bad region. In fact, even good wide-field eyepieces have this problem to a degree. Remember that you get coma as you move away from the field centre. So at certain magnification/focal ration combinations you won't want to be observing a planet near the edges of a wide-field eyepiece. I find the Radians are a good compromise in this regard. The 60 degree field feels quite generous and the 20 mm eye relief is very nice indeed. If there's a nice one on the second hand market, I'd gobble it up.

[wookie1965]

Ive got a skywatcher 150p which is a f5 scope i was looking for ages looking for eyepieces i looked at this http://www.swindonstargazers.com/beginners/eyepieces.htm then this the i rang Alan at skys the limit and went with BSTs and there brilliant great in a fast scope so clear eye relief is amazing espedially if you wear glasses like i do.