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Need advice on first eyepiece purchase


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I'm planning to buy an eyepiece to improve my viewing of planets. My question is which would be the best among my choices?

  1.  5mm Celestron Omni EP
  2.  7 or 8 mm Celestron Omni EP
  3.  8-24mm Zoom Celestron Omni EP
  4.  2x barlow + 15mm Celestron Omni EP combination

My scope specs: Refractor with 700mm focal length,  70mm objective,  10mmEP  and 20mm EP.

Thank you and Mabuhay.


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I think a 15mm Omni Plossl with a Barlow would be the most adaptable combination. The 15mm Omni is pleasant to use and has a decent eye relief of 13mm and good sized eye lens diameter. On its own it would give you about a 47x magnification and 93x with the Barlow. I have the Omni 12.5mm, 15mm and 2x Barlow. They are well made and good quality for the price they normally retail at. The draw tubes feature the older square cut safety undercuts and may prove tricky to extract from a diagonal with a brass compression ring. The Barlow element can't be unthreaded from the Omni Barlow.



Edited by Mak the Night
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You've got a 10 and a 20mm EP.  These will give mags of x70 and x35.  

A 15mm Omni gives x47.

A x2 Barlow on the 10 and the 15 would give x140 and x93.

That gives you a range of x35, 47, 70, 93, and 140 - a good spread for looking a Jupiter and other objects, bearing in mind your max mag for that 'scope is about x140. 

So you need one Barlow and one EP.  (You could perhaps then get a 6mm Omni for x117 to "fill the gap".)

There are of course several solutions - this is just my suggestion!

Your refractor is the same as I started with, and I got good results on some DSOs, clusters, planets, and star-splitting.



Edited by cloudsweeper
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2 hours ago, bingevader said:

Good advice already given.

Option 4.

With the barlow, you'll maintain the eye relief of the eyepiece you're using.

The 15mm (and the 10mm) with the barlow will be a more comfortable option.


A barlow actually extends the eye relief a bit so that can help with eyepieces that have rather short eye relief in their "native" state.


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21 hours ago, aeajr said:

I really enjoy the Celestron 8-24 zoom that I have.   It is my single most used eyepiece.   If you had said barlow + zoom then that would have been my recommendation.   But the barlow adds so much flexibility to your eyepiece set that it is hard for me not to recommend it.

It never entered my mind that it is possible to use a barlow with a zoom EP.  Since a zoom EP is also on my wishlist, I might as well go with your advice:

A 2x barlow + Celestron 8-24 zoom EP

Thank you to all who gave their advice.

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Low cost barlow + low cost zoom = well it will work but don't expect great optical quality. Fixed focal length eyepieces such as decent plossls or orthos will provide somewhat better quality views.


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