BARLOW LENS RECOMMENDATIONS

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BARLOW LENS RECOMMENDATIONS

Postby homer hotspur » Sun Jun 15, 2008 2:16 pm

[size=2]As per the subject title, can anyone recommend a 2x Barlow lens for my refractor telescope please. I would probably budget around £50. [/size]

[size=2]I have noted that some 2" x2 barlows seem to be cheaper than 1.25" versions even though the 2" model comes with an adapter. I already have an adapter anyway so could get a 2" barlow. Why are they cheaper and which would be best?[/size]
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RE: BARLOW LENS RECOMMENDATIONS

Postby brianb » Sun Jun 15, 2008 2:50 pm

[quote] I have noted that some 2" x2 barlows seem to be cheaper than 1.25" versions even though the 2" model comes with an adapter. I already have an adapter anyway so could get a 2" barlow. Why are they cheaper and which would be best? [/quote]
"Cheap" is not necessarily "good" - the better Barlows use three or four element designs with special glasses, consequently they produce better images especially off axis, and especially with scopes with a small focal ratio.

There is also an issue which [i]may[/i] affect you with 2" Barlows. If you place them before the diagonal, you will have a long back focus making the magnification greater than the design was computed for. If you try to place them in the diagonal, they will probably not fit right in, resulting in not being able to get to focus. This is less of a problem with SCTs because of the huge range of back focus they can cope with, but nevertheless there may still be a danger of the nose of the Barlow hitting the diagonal mirror or prism.

If you want a Barlow for imaging with a web cam, a 1.25" fitting one will provide a sufficient field. If you want a Barlow for "wide field" imaging using a DSLR, a photographic tele-extender will do the job better, the image field will be flatter and there will be less distortion especially at the corners ... but then photographic tele-extenders are usually 7 element designs.

For visual work, the 1.25" x2 Meade "shorty" Barlow is fine. For imaging, slightly over your budget but the 1.25" AE x4 Imagemate (AC519) is much to be preferred, though IMO x4 is far too much for visual work. The various Televue Powermates are excellent but way out of your price bracket!
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RE: BARLOW LENS RECOMMENDATIONS

Postby keithmorris » Mon Jun 16, 2008 10:50 am

Whichever Barlow you go for try and get an APO or ED Barlow. There are many to choose from.

Imagemate x2
Imagemate x2.5
Imagemate x3
Imagemate x4

Meade APO 140 x2

These are are all 1.25"

There are some good 2" Barlows to be had for a very reasonable price. Last year at Kelling Heath I bought a Skywatcher ED x2 Barlow in 2" fitting for about £45.00, I have been very pleased with this. In fact it is my preferred choice for when using my ED80 refrator.


Keith
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RE: BARLOW LENS RECOMMENDATIONS

Postby sftonkin » Mon Jun 16, 2008 6:20 pm


[quote]ORIGINAL: Homer Hotspur

[size=2]As per the subject title, can anyone recommend a 2x Barlow lens for my refractor telescope please. I would probably budget around £50. [/size][/quote]

If I were you I'd increase the budget and get a Celestron Ultima x2 Barlow. IMO it is the least expensive one worth getting. (IME people who sing tgeh prises of lesser Barlow's have nothing decent to which to compare it.)
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RE: BARLOW LENS RECOMMENDATIONS

Postby chris sant » Fri Jun 20, 2008 10:06 am

the celestron Omni 1.25 in is also good value I personally use the celestron kit barlow and no no problems yet (apart from the corrosion)
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RE: BARLOW LENS RECOMMENDATIONS

Postby lozenger » Tue Jun 24, 2008 9:20 pm

Celestron Do a Barlow which has a Thread B[u]uilt onto it, so Great to use with your DSLR[/u]
[u][/u]
[u][/u]
[u]you would of Course need to buy the Correct T-ring for your Camrera which start from £9.99[/u]
[u][/u]
[url=http://cgi.ebay.co.uk/Celestron-Barlow-Lens-x2-Universal-Camera-Adapter_W0QQitemZ230255190490QQcmdZViewItem?_trksid=p3286.m20.l1116]http://cgi.ebay.co.uk/Celestron-Barlow-Lens-x2-Universal-Camera-Adapter_W0QQitemZ230255190490QQcmdZViewItem?_trksid=p3286.m20.l1116[/url]

We do the 2" but only good if you have Lots of 2" Equipment.


simon
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RE: BARLOW LENS RECOMMENDATIONS

Postby gord » Thu Jun 26, 2008 10:16 am

[quote]ORIGINAL: sftonkin


[quote]ORIGINAL: Homer Hotspur

[size=2]As per the subject title, can anyone recommend a 2x Barlow lens for my refractor telescope please. I would probably budget around £50. [/size][/quote]

If I were you I'd increase the budget and get a Celestron Ultima x2 Barlow. IMO it is the least expensive one worth getting. (IME people who sing tgeh prises of lesser Barlow's have nothing decent to which to compare it.)

[/quote]

The Ultima gets good press - so you could go for the Orion Shorty Plus (note the "Plus") x2 Barlow from either Telescope House or SCS Astro. It's a rebranded Ultima and is only about 50 quid (instead of 80 for the Ultima).

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RE: BARLOW LENS RECOMMENDATIONS

Postby gord » Thu Jun 26, 2008 5:46 pm

Is shop advertising being allowed on the forum again than [8|]
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RE: BARLOW LENS RECOMMENDATIONS

Postby philip pugh » Tue Jul 08, 2008 5:00 pm

I have a 3x Moon fish Group Barlow and am happy with it and a Soligor 2x, which is OK but not great.

A bit above your budget is the Coronado CEMAX 2x Barlow.
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RE: BARLOW LENS RECOMMENDATIONS

Postby samtheeagle » Fri Mar 13, 2009 1:03 pm

Anyone have an opinion on this Barlow? [url=http://www.scopesnskies.com/prod/51.html]http://www.scopesnskies.com/prod/51.html[/url]

It appears to be similarly spec'd to the Celestron Ultima / Orion Shorty Plus. And is made in Japan is the label on the box it accurate. Seems like it [i][b]could[/b][/i] be good value.

I've searched high and low for the orion, the only place I found was out of stock and thought that it was discontinued :(
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