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Celestron 2x Ultima Barlow

Celestron 2x Barlow Ultima

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#1 Neil

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Posted 07 December 2012 - 04:16 PM

I have had a couple of barlows over the years and none of them until now have lived up to their billing. I managed to obtain a Celestron Ultima 2x barlow secondhand mainly for planetary imaging. It had a lot to live up to, since my primary image amplifier is the Takahashi ExtQ 1.6x used with a Mewlon 250CRS this combination delivered a focal length of 4000mm. Placing the Celestron inline with the Mewlon and my DMK21 gave a focal length of 5000mm and filled my screen with Jupiter.

 

To my surprise the Celestron delivered a clear, clean and bright image of Jupiter. I was expecting to struggle with the gain to get an acceptable image and this proved not to be the case at all. I'm very satisfied with the Celestron and it is definitely a keeper...

 

When the weather finally clears I will see just what can be achieved with my Mewlon. Until now I have only managed 3 imaging runs under average condition with this combination.

 

Celestron.JPG

 

A small but powerful package...



#2 Brantuk

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Posted 07 December 2012 - 08:12 PM

Best barlow under £100 (imho) and identical to the Orion Shorty Plus. :)



#3 Lenny

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Posted 29 March 2013 - 09:57 PM

Hi:

 

I purchased a Celestron 2X Ultima Barlow about 6 years ago.  It has always provided me with good views when used with any of my eyepieces.  Yet, if I had a complaint it is one of dimness.  It seems to me that when the Ultima Barlow is used with certain eyepieces the view it produces is slightly dimmer than what I expect.  I have noticed this dimmer image when combined with my Celestron 12.5MM Ultima eyepiece and some of my cheaper plossls such as Orion's Sirius or Hands on Optics GTO.   I believe this is a result of extra lens in the Barlow.  The Ultima has 3 lens while standard Barlows have 2.  In most cases, the extra lens is a good thing, designed to cut down on distortion similar to an APO refractor.  But when used with the a 5 lens eyepiece such as the Ultima, or those with inferior coatings, it seems to result in slightly dim views. 

 

I also own a standard Celestron 2X Barlow.  When I use it with the before mentioned eyepieces the view is a bit brighter, what I expect it should be.  However, the standard has its own drawbacks.  It produces glare when used on a bright object at high mag.  It also seems to have a much more limited FOV then the Ultima Barlow.   Another difference is in the magnification produced.  It is well known that the Ultima actually produces magnification in excess of 2X.  Some have suggested the mag to be as high as 2.3X.  The standard seems to be 2X.

 

I own a TeleVue 3X Barlow.  I purchased it to use with my Orion 80MM F7.5 APO  to achieve high magnification.  It does a very good job when used with any of my eyepieces.  I don't believe it provides as sharp an image as the Ultima Barlow, nor have I noticed the 3X dimming the image, but than again, I am not really comparing apples to apples.  

 

One final note.  I have read that the Ultima Barlow has been discontinued as has the Orion Shorty plus. 

 

Lenny



#4 tasco

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Posted 09 April 2013 - 11:34 PM

when i got mine i read the orion shorty plus was a slightly different design  (length?)- i got the antares 2X APO made in japan (antares ultima clone) older now but still a fine piece of glass, last year i wanted more f/l and didnt wanna spend the money for powermate, i got the GSO 2.5X at a ridiculous low price- no regrets, the barlow hasnt let me done