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View Full Version here: : eyepieces for poor conditions


robagar
04-05-2007, 01:53 PM
I live somewhere where the seeing is almost always pretty terrible, but all the same I want to get a high power eyepiece, say a 5 or 6mm plossl for my 8" dob.

The question is this: in poor seeing conditions, is a high quality eyepiece still better than a cheap one, or do bad conditions bring all eyepieces down to the same level?

I'm thinking of a Vixen LV, just because I like the 10mm one I already have. But if it would be wasted, I would rather save the money for the wide angle eyepiece fund and get a cheapo GSO one :)

matt
04-05-2007, 01:56 PM
G'day Rob.

I'm afraid you've pretty much answered your own question.

Poor seeing conditions are poor seeing conditions, no matter what the eyepiece.

And as you'd know, the higher the magnification the better conditions you require to make any detail out in the eyepiece.

Perhaps see if you can get a loan of something in the range you're thinking of before buying?

janoskiss
04-05-2007, 02:15 PM
seeing cannot be helped by EP. best bang for buck are the TMB/Burgess planetaries. Very nice EPs will work flawlessly in your scope. :) 3-for-2 deal from Frontier Optics is awesome value.

iceman
04-05-2007, 02:19 PM
Why is the seeing bad in Cairns? It's usually above the jetstream so I would've expected it to be fairly good up there?

Are you sure it's the seeing conditions?

How are you judging it?
What telescope are you using?

robagar
04-05-2007, 03:24 PM
I always assumed it was something to do with the heat and high humidity, and air turbulence caused as the wind blows inland up the range to the tablelands above Cairns. It's certainly much, much better inland where it's dryer and cooler.

Looking at diffraction rings, it almost alway looks more like #1-3 on from the animations on http://uk.geocities.com/dpeach_78/pickering.htm, but they usually look rather more spiky around the outside edge. Could this be something other than seeing?

The scopes an 8" newt btw.

Those Burgess ep's do look nice. hmmm... :)