How far can I push the ED100?

[Zeffer]

I know this depends a lot on seeing etc. but what's the realistic maximum magnification? I am trying to work out whether to get an EP around 5mm or go further to say 3mm or less.

I would mostly be looking at planets and the moon with this kind of EP although I like splitting doubles. At least I think I do - it's been so long since I have been out that I have forgotten!

[GazOC]

I got plenty of use out of my 4mm ortho (x225) on that scope on Jupiter and Saturn Justin. I didn't try any higher because I didn't have the eyepieces but I got the impression I was pretty close to what my skies and the scope could usefully take on those objects.

You'll be able to go higher on the Moon and higher again on double stars though.....

[Andrew*]

I got excellent results using a 4mm ortho (225x mag) with the ED100. Like this, the double double was split with ease!

A 4mm ortho, Burgess/TMB planetary, or, if you're feeling extravagant, a TeleVue Nagler 3-6mm zoom would probably work very well for you. I think the "twice the aperture in mms" saying is only a very general guide, and with a scope of the ED100's calibre, you can stretch the "limit" a bit!

Saying that, perhaps 3mm on the Nagler zoom would get very little use, knowing UK skies.

Andrew

[Andrew*]

honestly, I wasn't talking to Gaz while composing that post!!

[GazOC]

At least we were consistant Andrew....

[Zeffer]

Thanks for the input. I have seen a 2.5mm Nagler but it sounds like it wouldn't get used that much! I'll wait until I see something good around the 4mm mark.

[Andrew*]

yep!

That 2.5mm Nagler would definitely not get enough use at that power to justify the cost IMHO. A 3.5mm Hyperion might be a good choice, actually.

Andrew

[lunator]

Zef

As a general rule of thumb magnification of 25x aperture inches is considered average but on good nights x50 is fine.

You can go beyond this if the seeing allows but the nights this occurs may be limited.

Cheers

Ian

[Zeffer]

Thanks for that - glad I asked before I bought a fantastic EP of no use whatsoever!

[John]

....Saying that, perhaps 3mm on the Nagler zoom would get very little use, knowing UK skies.

Andrew

Yep - that's what I'm finding with my F6.5 ED102 - the 6mm-4mm range is getting lot's of use and the 3mm very little at the moment. Mind you 6mm, 5mm and 4mm eyepieces of the quality of the Nagler zoom would cost a lot of dosh so I'm not complaining - and theres always the sub 4mm range available if I get a really nice night

Interestingly, I'm finding that I prefer to barlow the 9mm and 7mm Naglers for high power use in my dobsonian -you retain the 82 degree field of view that way which helps a lot with tracking (the Nagler zoom's field is 50 degees thoughout it's range).

John

[Zeffer]

How are you finding the 7mm? There's one on offer at the moment that I have sent an Email about. I really want a 13mm at some point but this looks interesting.

[John]

How are you finding the 7mm? There's one on offer at the moment that I have sent an Email about. I really want a 13mm at some point but this looks interesting.

I really like mine - it's a type 1 which has a little less eyerelief than the more recent type 6's (10mm V's 12mm) and the coatings are not supposed to be quite so good on the type 1 but TBH I can't notice much difference between the views of my 7mm T1 and my 9mm T6 - apart from the magnification that is.

Another difference is that T1's go for under £100 used wheras T6's are more like £130-£140.

Sorry for the short term thread hijack Zeffer

John