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Looking to expand my viewing with my Celestron Astro Master 70 AZ, I got last summer what would you recomind to buy? I have the standered 20mm and the 10mm eyepiece that came with the telescope,and thank you for replying.

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Hello JB97,

The wanting of a telescope in the first place is due to the desire to see faraway objects up close; else, one would choose binoculars instead.

The eyepieces and accessories that you get for the present telescope can be used for other telescopes that you may acquire in future, so feel free to spend a little, yet not break the bank.

One item that stands out above all is a good star-diagonal, first and foremost.  The diagonal that came with your kit is not really suitable for use at night; for astronomy.  It's an erect-image, or Amici, diagonal, and for use in the daytime for land-viewing only.

This Celestron prism star-diagonal would really open up the light path of your refractor, and allow you to push the telescope's main lens for all it's worth, and at night...

http://www.rothervalleyoptics.co.uk/celestron-90-degree-star-diagonal-125.html

Synta includes that same diagonal with their larger Celestron Schmidt-Cassegrain kits.  I have that one myself, and for my smaller refractors...

94115-Ah.jpg 

Your refractor has a focal-length of 700mm.  To find the power of any given eyepiece when used with your telescope...

700mm ÷ 20mm = (35x)

To assist the finder of your refractor, and in finding objects to observe close up, either a 32mm or 40mm Plossl may be used, and for the lowest power and the widest and brightest views possible...

http://www.365astronomy.com/32mm-GSO-Plossl-Eyepiece.html  (22x)

http://www.365astronomy.com/40mm-GSO-Plossl-Eyepiece.html  (18x)

Either one would allow for the simulation of one half of a pair of 20x70 binoculars; that is, your telescope would then act as a 20x70 monocular, and to scan the night sky.

The eyepieces that came with your kit will perform better with a proper star-diagonal.  If the bundled eyepieces are still not to your liking afterwards, then you can get new eyepieces to replace them, beginning from 20mm on down...

https://www.harrisontelescopes.co.uk/acatalog/Revelation_20.0mm_Plossl_Eyepiece_1.25_.html#SID=1393 (35x)

A wide-field 20mm... http://www.teleskop-express.de/shop/product_info.php/info/p2643_GSO-SuperView-20-mm---1-25--WA-eyepiece---70--FoV.html (35x)

It's a real shame the wide-field 20mm is not available in the UK.  In any event, it would most certainly make for a most worthy acquisition; not to mention the wide-field 15mm to boot...

http://www.teleskop-express.de/shop/product_info.php/info/p4839_GSO-SuperView-15mm---1-25--WA-eyepiece---70--FoV.html (47x)

On a good night of seeing, the maximum power that your telescope should reach is approximately 140x, and for observing the craters of the Moon, in the splitting of double-stars, and of seeing meaningful details of the larger planets.

To reach 140x with your telescope...

700mm ÷ 140x = a 5mm eyepiece, or a 6mm for 117x...

http://rover.ebay.com/rover/1/710-53481-19255-0/1?toolid=10029&campid=CAMPAIGNID&customid=CUSTOMID&catId=625&type=2&ext=282304579936&item=282304579936  

That one would ship from Hong Kong.  Or, it can be had locally...

http://www.365astronomy.com/TS-Ultra-Wide-Angle-Eyepiece-6mm-1.25-66o-with-Improved-Coating.html

Both are the same eyepiece.  You can find lots of good deals on all different kinds of eyepieces on eBay, if you don't mind ordering from China, and waiting.  I've had very good luck in ordering from China. 

Here are 317 results, and for just a 5mm eyepiece...

http://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p2047675.m570.l1313.TR1.TRC0.A0.H0.TRS0&_nkw=5mm+eyepiece&_sacat=0

Just take your pick, and take your chances.

But you're going to need a star-diagonal, first.  Try your 20mm and 10mm with it, and then go from there.

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I have some very good friends with scopes quite like yours, and similar. I'm hearing rave-reviews on the Vixen NPL Eyepieces. They seem to have a Lanthanum -glass lens-element which results in excellent, flat edge-to-edge views. And the prices are those of a simple Plossl. I have some of an older version of this series from Vixen - and I bought them in 2003. I'm still kicking myself for not buying the entire series back then! Have a link:

http://agenaastro.com/eyepieces/1-25-eyepieces/shopby/vixen_npl/vixen_optics.html

Available worldwide at low cost.

Dave

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12 minutes ago, Dave In Vermont said:

I have some very good friends with scopes quite like yours, and similar. I'm hearing rave-reviews on the Vixen NPL Eyepieces. They seem to have a Lanthanum -glass lens-element which results in excellent, flat edge-to-edge views. And the prices are those of a simple Plossl. I have some of an older version of this series from Vixen - and I bought them in 2003. I'm still kicking myself for not buying the entire series back then! Have a link:

http://agenaastro.com/eyepieces/1-25-eyepieces/shopby/vixen_npl/vixen_optics.html

Available worldwide at low cost.

Dave

What a coincidence, as I've just returned inside, and from fighting fast-moving clouds rolling over the Moon.  It's 67°F here, and the winds are ferocious.  I did manage to get two good afocal shots, and through my Vixen NPL 30mm, and via my new Zhumell Z100 100mm f/4 Newtonian...

011217-30mmNPL.jpg

011217-30mmNPL2.jpg

I'm going try for some more later this morning, and yes, oculars from within the Vixen NPL line would make for a very good choice indeed.

Edited by Alan64
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Hi JB, a 32 mm Plössl would be nice. It would give you the widest views your 1.25" diagonal allows.

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7 minutes ago, Alan64 said:

What a coincidence, as I've just returned inside, and from fighting fast-moving clouds rolling over the Moon.  It's 67°F here, and the winds are ferocious.  I did manage to get two good afocal shots, and through my Vixen NPL 30mm, and via my new Zhumell Z100 100mm f/4 Newtonian...

011217-30mmNPL.jpg

011217-30mmNPL2.jpg

I'm going try for some more later this morning, and yes, oculars from within the Vixen NPL line would make for a very good choice indeed.

I'll just be sending this information from this thread to them! They''ll get a kick out of the content, as well as the synchronicity it has managed to evoke! :D

What fun!

Dave - Oh! Hi Ruud.

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Before you run off and buy eyepieces a question: Has that scope got the erect image diagonal as part of it ?

If it has then I think that the prism that makes the viewing "normal" also pushes the focal plane outward and so many eyepieces will then not focus correctly. You just cannot wind the focuser outward enough.

In which case the first item will be a normal mirror diagonal to replace the erect image item. I suggest the new diagonal instead of a short extender as I would also guess that the Amici prism degrades the image a bit.

If the diagonal is a normal mirror already (sometimes they were supplied with mirror) then as mentioned the Vixen NPL's are good plossl eyepieces at about a fair cost compared to the scope. I tend to consider that you likely do not want to spent more on one eyepiece then the scope cost.

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Hello and welcome to SGL

Obviously eyepieces are relevant depending on your budget and what you are attempting to achieve in optical quality, field of view , eyerelief, quality of build. If you are after an eyepiece with good quality optics , field of view of 60d (more than a plossl) and good eye relief, that do not cost a fortune. Then the BST explorer/starguider are a great choice. These eyepiece will not blow the bank balance also as they are around £50 each. The BST have a good following on SGL and are a well tried and respected eyepieces. 

I hope the above helps☺

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I have the cheap Celestron 1.25" star diagonal, and it is the weakest link in your setup.  Replace it ASAP with a much improved one like this one or this one.  The difference is far from subtle in any eyepiece.

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