Eyepiece advice...

[Whippy]

After my last session I thought to myself 'Barlows are good for brighter stuff, but for the smaller faint objects, it just dims them out to nothing. I need to sort something out'. My shortest EP is 8mm, I know that in theory that I could go down to 2.5mm to get my apparent maximum magnification but I'm pretty sure that in the real world (or my back garden) that I'll probably never see a decent image because of conditions. So I'm thinking of maybe getting something around 5mm at first and perhaps maybe a 3mm at some point.

Would it be worth my while going all the way down to 2.5-3mm? Would I actually use it that often? And of course any recommendations on EP's would be most welcome...

Cheers,

Tony..

[Black Shuck]

Tony,

Had my 6mm Omni Plossl barlowed the other week on the C8N.

Not a bad view of Saturn (I was suprised that it was still relatively bright), the seeing wasn't brilliant and it was bouncing around a bit. My Father, who is 82 and has had cataracts, could see it quite clearly too despite the poorish eye relief. Not sure how it would be with fainter objects/DSO's though???

Lets put it this way - I was encouraged enough to maybe try a 3mm for planetary views sometime.

HTH

Bill£

[barkis]

After my last session I thought to myself 'Barlows are good for brighter stuff, but for the smaller faint objects, it just dims them out to nothing. I need to sort something out'. My shortest EP is 8mm, I know that in theory that I could go down to 2.5mm to get my apparent maximum magnification but I'm pretty sure that in the real world (or my back garden) that I'll probably never see a decent image because of conditions. So I'm thinking of maybe getting something around 5mm at first and perhaps maybe a 3mm at some point.

Would it be worth my while going all the way down to 2.5-3mm? Would I actually use it that often? And of course any recommendations on EP's would be most welcome...

Cheers,

Tony..

That seems to me to be too high a power, I would expect dimming of the faint object to reach almost invisibility. I don't know the focal length of you scope, but assuming f5, your mag. is going above 300 times. I know under ideal conditions 50x per inch is possible, but I reckon 40xpi is max with our skies. What would be your target at such high magnification. Certainly not a DSO surely?.

[Whippy]

Ron, my 8" reflector is a straight f5 while my 4" 'frac is f10. So yes, in theory the maximum magnifications are going to be about x400 and x200 respecitively. But as we well know, conditions are rarely perfect so hence I was asking if it is actually worth going for something really short like a 2.5-3mm EP also bearing in mind that the probable extra glass on something like that would probably dim an object almost as bad as a barlow would anyway. ..I'm finding small objects like the Ring Nebula are tiny even in my 8mm Hyperion. That's at x125. So I'm looking at getting something about 5mm soon (probably another Hyperion), that should be ok for most nights I figure.

[Kai]

What about one of those Baader orthos,they arent too expensive IF you can live with the eye relief

[John]

Having tried short focal length eyepieces (down to 4mm at any rate) and barlowing longer fl ones I tend to use the barlowed approach more often because it gives me the more comfortable eye relief of the longer focal length eyepiece coupled with the higher power. The proviso is to use a decent quality barlow (a Celestron Ultima 2x in my case).

I have compared the views with a Tele Vue 8mm plossl combined with the Ultima Barlow with a good quality 4mm ortho in the same scope "back to back" so to speak and I could not detect any loss of quality in the barlowed combination. I guess there must be some slight light loss due to the additional glass but I really could not notice it.

John