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Thinking About Celestron X-Cel 3X Barlow For C5+

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#1 RalphMeisterTigerMan

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Posted 09 April 2020 - 07:57 PM

For Celestron C5 owners or equivalent, do you use barlows to ramp up the magnification with a quality eyepiece?

 

I'm thinking about the Celestron X-Cel 3X or 2X barlow. If any of you have any of the two, let me know what you think. If any of you happen to use any other barlows for a small-ish SCT telescope, let me know what you use and recommend.

 

BTW, the eyepiece I'm currently using, and enjoying, is the Televue 24mm Panoptic. What's a good barlow to mate with it to my C5+?

 

Thank-you and clear skies!

RalphMeisterTigerMan



#2 SeattleScott

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Posted 09 April 2020 - 08:00 PM

I would be surprised if the 24 Panoptic didn’t vignette in a 1.25” barlow. I mean it should work as long as you don’t expect it to be 68 AFOV when barlowed.

Sometimes it is just better to get a shorter FL eyepiece.

Scott
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#3 MartinPond

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Posted 09 April 2020 - 08:56 PM

'Barlow' does not automatically equal 'vignettes'.

The generalization seems to be a durable urban legend.

 

To  be more fine-grained and accurate:

 

A 24mm//68afov eyepiece would vignette in most

  shorties, and would not vignette in a long barlow

  or a telecentric/focal-extender.  This I know from

  experience, at 23mm//70afov.

 

It has been observed by others that a TV mid-length

   Barlow also avoids such vignetting.  Can we confirm?

 

I don't know about the X-Cel LX Barlows, though.

Maybe someone could give it a check.


Edited by MartinPond, 09 April 2020 - 08:59 PM.


#4 SeattleScott

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Posted 09 April 2020 - 08:59 PM

Well said.

The barlows the OP mentions are short so I would assume they would vignette a 24 Panoptic unless someone has experience using it and can confidently say otherwise.

Scott

Edited by SeattleScott, 09 April 2020 - 10:56 PM.


#5 csrlice12

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Posted 10 April 2020 - 12:10 PM

At 3X, the Orion trimag is hard to beat.  It is a long  barlow.



#6 SeattleScott

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Posted 10 April 2020 - 12:58 PM

Nice, 24mm clear aperture so it won’t vignette a 24 Pan much. However it is going to be tough to fit a long barlow in a 1.25” diagonal without hitting the diagonal mirror. And few people use 2” diagonal with a C5. So the OP is probably kind of stuck with using a shorty barlow that will almost certainly vignette a 24 Pan. Possibly a telecentric option would work but now the price just went up.

Scott


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