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eyepiece selection suitable?

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#1 markgf

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Posted 11 December 2012 - 11:57 PM

Hi, I'm superseding my 10mm and 25mm standard EPs that came with a 6" F8 dob which has a 2" focuser. There's more telescopes in my future I think. Is either of the following EP selections sensible?

Either:

2" Baader 36mm x 72D
2" AT or similar 2x barlow
1.25" ES 11mm x 82D
Does anybody ever actually barlow big EPs (36mm)?

or:

2" Baader 36mm x 72 (future)
1.25" ES 24mm x 68 (maybe),
1.25" Baader 8-24 zoom (24mm end of zoom is only 42*)
I don't know whether to get a 1.25" or 2" barlow with this lot.

As a 3rd option, I might just make do with the zoom and the standard EPs for now, but will want to upgrade in the not too distant future.

Sugestions please?
Thanks...Mark

#2 Allan...

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Posted 12 December 2012 - 12:17 AM

I believe that most folks choose a 1.25" barlow; myself included. I only have one two inch eyepiece (30mm Owl) and likely every other eyepiece will be 1.25" in the future. I, too, have contemplated that Baader zoom; sure looks good; only thing stopping me is the comments re narrower FOV at 24mm. I got spoiled by a few 70+ deg eyepieces; not sure that I want to go downward. I dont think you can go wrong with the ES eyepieces. Good luck. Clare

#3 Jon Isaacs

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Posted 12 December 2012 - 07:07 AM

Sugestions please?



- I do recommend getting a longer focal length, wide field 2 inch eyepiece. You can increase the maximum field of view from about 1.3 degrees to about 2 degrees, quite useful in finding objects and the views should be quite wonderful.

- 2 inch Barlows are becoming more popular, I don't own one though I have been tempted a time or two. From my standpoint, the fundamental problem with a 2 inch Barlow is that it transforms a heavy, bulky, long focal length 2 inch eyepiece into a even heavier, bulkier, short focal length 2 inch eyepiece. With a Dob where balance is an issue, it doesn't seem like a reasonable choice.

The one good thing is that in a fast scope, a Barlow will help correct the eyepiece aberrations, so that 36mm transformed into a 18mm will be sharper off-axis in an F/5 scope but at F/8, this is of less value.

Jon

#4 Messyone

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Posted 12 December 2012 - 08:02 AM

Hi Mark,
Another Aussie on...terrific.
2" barlows...don't bother just yet.I have one but have never used it. ES 11 is a good choice put a 1.25" barlow with it and it works!
I'd get the ES 35mm 82* ( think it's 35mm) instead of a Baader eyepiece, ES is really good stuff, for want of a better word!
Zooms, no idea.
Matt

#5 BDS316

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Posted 12 December 2012 - 08:46 AM

40mm 2 inch Sterling Plossl

14mm ES 82 N2

8.8mm ES 82 N2

a good 2x Barlow

Minimalist. High Quality. Reasonable prices.

#6 Billytk

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Posted 12 December 2012 - 12:55 PM

I have a Baader zoom and I love it.

#7 markgf

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Posted 12 December 2012 - 08:16 PM

Holey macarone!
You mean I have to MAKE MY OWN DECISION??

OK. The zoom wins, possibly with the 1.25" (2.25x) barlow that's made for it. For the time being, this will displace fixed length EPs up 24mm. Should be an interesting experiment.

When I've recovered from festive season wallet hemorrhage, I'll decide between a low power 2" EP (to fit M31 or Orion's sword in one go) or an ES24x68 to max out total FoV through a 1.25" EP. The ES EP might cost twice as much by then, but...too bad, so sad. :bawling:

Hi Matt down under. I like the ES gear but am concerned their 2" EPs are just too massive for my baby dob (6"). As it is, I'm investigating replacing the stock finder with a nice light Rigel Quickfind or 5mW laser, if I can work out how to attach them. I'm aware of laser safety issues.

Clare, I'm a bit nervous about the zoom's narrow-ish 42* AFoV at 24mm too, but forgive it because it gives 70* at 8mm. Plus I'm considering a separate wide field fixed length 24mm. Also, Our eyes' visual acuity is only any good very close to straight ahead, so a wider fixed length EP would mainly be for 'finding', or just 'looking out the window'. Other threads on planet viewing and binary-splitting have very strong, very experienced advocates for ortho's, etc because they are sharp, with little concern about their narrow FoV (compared to some recent EPs).

Does anybody know which EP clamp to buy to fit to the Baader barlow that's made for the zoom, so that it can accept EPs with no filter thread? Can a filter still be used if an EP's thread is used to attach it to the Baader zoom's barlow?

Thank you All, I haven't placed the order yet...Mark

#8 Allan...

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Posted 12 December 2012 - 08:37 PM

Ok, Mark...sounds great on the Zoom. Im still on the fence and I shouldnt be concerned, either re the 42* APOV at 24mm as I have a 30mm and a 25mm. I just like the idea of not changing eyepieces when its cold (and its cold here). I wonder what the FOV is at the other settings (ie: 18, 14, etc). 70* at 8mm is excellent. Re the filters, I bought an Antares centering adaptor (no more thumbscrews on 1.25" eyepieces); the adaptor has 2" threads on the bottom as well., though I know that 2" filters are more expensive. Lots to consider; glad we have a huge support group here. Clare.

#9 markgf

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Posted 12 December 2012 - 10:23 PM

Thanks Clare
Yes. This is a great community.

Re the 24-8mm zoom, the shorter the focal length the greater the FoV, more so at the short end. My main concern is the short eye relief at 8mm zoom. About 8.3mm relief (measured by others) rather than 12mm as claimed by Baader. I don't know if that means lots of cleaning of oily marks from eyelash swipes.

There's an enormous Baader zoom thread on this site somewhere (5,000+ posts) but I can't find it just at the moment.

Thanks for the adapter heads up. I know so little about this stuff. I'll have to bend the ear of a sales dude at the (not very) local scope shop.
Cheers...Mark

#10 Allan...

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Posted 12 December 2012 - 10:59 PM

Ok on the eye relief on the Zoom, Mark. I might have to think about that too; prefer longer ones. One thing re the Antares Centering adaptor (besides no more thumbscrews) is that even though its a 1.25" unit, the bottom is 2" and accepts all 2" filters. I was warned though, that a few eyepieces might have too long a shank (not sure what the proper term is) and might hit the filter. Not every eyepiece; just the odd one. Ive not found that as yet with any of mine. ps: say hi to Dunc down there in Walkabout Creek...(just joking...I know youre on the coast); imagine skies in Walkabout would be incredible. I have watched Season 1 of Supernova Australian TV series; very well done semi Sci-Fi/Astronomy and Britcom. Clare :jump:






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