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Antares Variable Zoom

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#1 eyeoftexas

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Posted 06 February 2024 - 07:47 PM

I just saw that Antares makes a 1.5x-2.5x 1.25” variable zoom.  I didn’t find any threads or reviews on it.  Does anyone have experience with it?

 

For reference: https://antares.spac...ariable-15x-25x


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#2 PJBilotta

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Posted 07 February 2024 - 01:35 AM

I've been wondering when someone would actually produce and market a decent "Zoom Barlow" again. The principle is pretty straightforward - a simple but sturdy sliding mechanism to vary the distance from the Barlow lens to the eyepiece - and it looks like Antares has designed it pretty intelligently. It's all about the optics, though.

While cool and versatile in concept, the challenge with a variable Barlow design - similar to the variable Denkmeier Powerswitch - is that significant refocusing is needed when you change powers. This can be a real pain in scopes like SCTs that require many turns of the focus knob to do it. I think that's why we don't see a lot of these on the market - particularly when there are now very good zoom eyepieces like the Baader that use the same principle, but cover a much wider range of magnifications.

Still, it looks like it could be a nice, versatile piece of kit if the optics are good. I think it's a new offering, so the only way to know might be to try it.

Edited by PJBilotta, 07 February 2024 - 01:38 AM.

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#3 eyeoftexas

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Posted 07 February 2024 - 03:22 PM

 I think that's why we don't see a lot of these on the market - particularly when there are now very good zoom eyepieces like the Baader that use the same principle, but cover a much wider range of magnifications.

Agreed.  But on the plus side a zoom barlow like this turns all of your eyepieces into zooms.  A Panoptic 24 becomes 24, 16-9.6mm.



#4 Mike B

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Posted 07 February 2024 - 04:50 PM

Agreed.  But on the plus side a zoom barlow like this turns all of your eyepieces into zooms.  A Panoptic 24 becomes 24, 16-9.6mm.

Seems like it’d be more like a 16mm to 9.6mm on the Pano?

 

many moons ago Antares/Speers came out with a “zoom” EP which incorporated a sliding Barlow element; it was a winner, too! Several FL range versions were made- I had the 8.5-12mm version… had decent ER & a very good 80* ultrawide view. 
 

My scopes at the time couldn’t really benefit from its FL range, so I foolishly sold it off. Nowadays I wish I’d retained it, as scopes change!

 

There are old CN reviews on these in the archives…


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#5 eyeoftexas

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Posted 07 February 2024 - 05:41 PM

Seems like it’d be more like a 16mm to 9.6mm on the Pano?

 

many moons ago Antares/Speers came out with a “zoom” EP which incorporated a sliding Barlow element; it was a winner, too! Several FL range versions were made- I had the 8.5-12mm version… had decent ER & a very good 80* ultrawide view. 
 

My scopes at the time couldn’t really benefit from its FL range, so I foolishly sold it off. Nowadays I wish I’d retained it, as scopes change!

 

There are old CN reviews on these in the archives…

I meant that, as an example, if you have a Pan24, you can use it, and then with the sliding Barlow, hence, 24mm then 16mm to 9.6mm.  

 

I have the Speers Waler 5–8mm version.  I love it.  Excellent wide field views.  That’s what made me consider this new Barlow.  Probably not as good, but I was hoping someone could tell us otherwise.


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#6 vrodriguez2324

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Posted 08 February 2024 - 02:45 AM

I see your example as a kit. 24 Pan + Zoom Barlow results in 24, 16-6.9 =)  Six one way half a dozen the other. 

 

I've seen a few of the Speers Waler zooms in the classifieds here and on AM but have never been able to score one. Read really good things about them. 

 

The Antares zoom Barlow looks interesting. 


Edited by vrodriguez2324, 08 February 2024 - 02:46 AM.

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#7 Sarkikos

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Posted 08 February 2024 - 10:13 AM

Years ago, there was a minor fad on CN about Zoom Sets.   Observers were rigging up eyepieces with Barlows so that the magnification could be varied. 

 

I don't recall now if they were just switching in and out different length extension tubes between the eyepiece and the Barlow, or if anyone had set up some kind of mechanism to vary the Barlow's magnification power on the fly.  A true variable Barlow would not have been bad.  But the idea of switching in and out different length extensions did not appeal to me at all.  It still doesn't.  

 

Mike


Edited by Sarkikos, 08 February 2024 - 10:56 AM.

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#8 Sarkikos

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Posted 08 February 2024 - 10:17 AM

One drawback for variable zooms is that you need to refocus for every variation of magnification.  This is why I don't like many zoom eyepieces. 

 

But I suppose refocusing a variable zoom - really, it's a variable Barlow - is better than switching in and out different size extensions between the eyepiece and Barlow or switching among separate Barlows with different powers.

 

Mike


Edited by Sarkikos, 08 February 2024 - 10:19 AM.


#9 Sarkikos

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Posted 08 February 2024 - 10:20 AM

Agreed.  But on the plus side a zoom barlow like this turns all of your eyepieces into zooms.  A Panoptic 24 becomes 24, 16-9.6mm.

Well, all your 1.25" eyepieces, at any rate.

 

Mike



#10 Sarkikos

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Posted 08 February 2024 - 10:24 AM

What we need is the Barlow equivalent of the tunable top on a Paracorr.  This would be a variable extension that is fitted between any 1.25" eyepiece and any Barlow.

 

Maybe the Barlow lens assembly of the Antares Variable Barlow can be replaced with the Barlow assembly of your choice?

 

Mike



#11 Sarkikos

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Posted 08 February 2024 - 10:27 AM

I meant that, as an example, if you have a Pan24, you can use it, and then with the sliding Barlow, hence, 24mm then 16mm to 9.6mm.  

 

I have the Speers Waler 5–8mm version.  I love it.  Excellent wide field views.  That’s what made me consider this new Barlow.  Probably not as good, but I was hoping someone could tell us otherwise.

Looks like the Speers Waler 5-8 Variable Barlow is no longer available new.

 

Mike



#12 Sarkikos

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Posted 08 February 2024 - 10:41 AM

Here's my Edmund variable Barlow from the early '70's.  I haven't used it in over 50 years.

 

Mike

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#13 Sarkikos

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Posted 08 February 2024 - 10:53 AM

Maybe something like this could be used to set up a variable Barlow:  Starboosa Telescope Camera Adapter   https://www.amazon.c...GhlbWF0aWM&th=1

 

Mike



#14 Sarkikos

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Posted 08 February 2024 - 11:04 AM

There was also this variable Barlow, discontinued, of course:

 

Meade Series 4000 1.25" #127 2x-3x Variable Barlow Lens # 07274  https://agenaastro.c...arlow-lens.html

 

Mike


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#15 PJBilotta

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Posted 08 February 2024 - 01:49 PM

Seems like it’d be more like a 16mm to 9.6mm on the Pano?

 

many moons ago Antares/Speers came out with a “zoom” EP which incorporated a sliding Barlow element; it was a winner, too! Several FL range versions were made- I had the 8.5-12mm version… had decent ER & a very good 80* ultrawide view. 
 

My scopes at the time couldn’t really benefit from its FL range, so I foolishly sold it off. Nowadays I wish I’d retained it, as scopes change!

 

There are old CN reviews on these in the archives…

This is exactly what every Zoom eyepiece is - an core upper eyepiece with a sliding Barlow - and the same principle used with the Baader Hyperion fine tuning rings that move the lower Barlow/Smythe lens farther from the upper elements. This variable Barlow design simply separates the two concepts so it can be utilized with any eyepiece. Where it improves over the standard Zoom eyepiece concept is that it may provide consistently wider views across the range - 68 degrees for every magnification in the case of the 24 Panoptic - provided the Barlow doesn't cause vignetting. This occurs with some Barlows when used with a max FOV eyepiece like the 24 Pan, ES 68 and UFF.


Edited by PJBilotta, 08 February 2024 - 01:54 PM.


#16 Sarkikos

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Posted 08 February 2024 - 02:16 PM

This is exactly what every Zoom eyepiece is - an core upper eyepiece with a sliding Barlow - and the same principle used with the Baader Hyperion fine tuning rings that move the lower Barlow/Smythe lens farther from the upper elements. This variable Barlow design simply separates the two concepts so it can be utilized with any eyepiece. Where it improves over the standard Zoom eyepiece concept is that it may provide consistently wider views across the range - 68 degrees for every magnification in the case of the 24 Panoptic - provided the Barlow doesn't cause vignetting. This occurs with some Barlows when used with a max FOV eyepiece like the 24 Pan, ES 68 and UFF.

Well, not exactly.   A fixed focal length eyepiece attached to a variable zoom Barlow is going to be even less parfocal within itself than the typical zoom eyepiece.  Actually, the variable zoom Barlow is not going to be parfocal at all.

 

Yep.  The Baader Hyperion fine tuning rings.  There was a minor craze about those a few years ago as well.  I never did see the value in it.  Do I want to be fiddling with a set of rings, screwing them on and off in the dark?  NOPE!  lol.gif   Better to use a good zoom eyepiece or two and/or a Barlow or two.  

 

The value I see in a variable Barlow is that you get to choose the eyepiece.   I see even more potential value in a variable extension that can be fitted between the eyepiece you choose and the Barlow (or Barlow lens assembly) you choose. 

 

Mike


Edited by Sarkikos, 08 February 2024 - 02:23 PM.


#17 eyeoftexas

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Posted 08 February 2024 - 02:58 PM

Note in the description: “… although re-focusing is required after any change.”  We don’t need another debate about parfocal or not.  This variable Barlow is not and does not pretend to be. 


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#18 Sarkikos

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Posted 08 February 2024 - 09:07 PM

Note in the description: “… although re-focusing is required after any change.”  We don’t need another debate about parfocal or not.  This variable Barlow is not and does not pretend to be. 

Will everyone who reads this thread bother to follow the link in the Opening Post and read the description of the Antares Variable Zoom?   Well, here it is, so they won't have to:

 

This 1.25" Variable barlow will allow you to change the magnification of any 1.25" eyepiece by 1.5X to 2.5X.  This can be done while observing, although re-focusing is required after any change.  There is no vignetting, even with low power eyepieces.

 

For refractors that came standard with an extended 2"-1.25" adapter, (Celestron, Sky Watcher, Orion etc) either of our parts MDA (low) or LPRA (ultra-low) will be required for the necessary in-focus.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   

Barrel Diameter - 1.25"                                                                                                                                                                                                                                                                                                                                                                          

Focal Length - 60mm

BARLOW, 1.25" VARIABLE 1.5X-2.5X  https://antares.spac...ariable-15x-25x

 

I am just stating facts.  No debate necessary.  A debate won't change the facts.  

 

Also, I wanted to make clear that a variable Barlow is not exactly a zoom eyepiece.   It's significant that Antares does not call it a Variable Zoom.  Antares calls it a Variable Barlow.

 

Mike


Edited by Sarkikos, 09 February 2024 - 10:33 AM.


#19 Sarkikos

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Posted 09 February 2024 - 10:10 AM

Yesterday, I ordered an Antares Variable Barlow from Telescopes Canada.  It was the last one they had in stock.  The website now says, "backordered."  https://telescopesca...le&_ss=e&_v=1.0

 

The Variable Barlow is to be shipped by FedEx three-day delivery.  Of course, shipping is delayed because the whole company packed up and went to a Florida star party!   Figures.  ohmy.gif

 

Mike



#20 Sarkikos

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Posted 09 February 2024 - 10:19 AM

To maximize TFOV in a 1.25" format, a 35 Ultrascopic would be ideal.   The effective focal length in the Antares Variable Barlow would be about 23mm to 14mm.  That might be nice for a finder eyepiece, and in general, as a good low-power range.  The product description says, "There is no vignetting, even with low power eyepieces."  I'll see if that's true for the 35 Ultrascopic.

 

To maximize AFOV, a hybrid 1.25"/2" Ethos would do the trick.  But that would make a long, heavy stack.   Maybe settle for a smaller, lighter eyepiece with 82-degree or less AFOV.  

 

Mike


Edited by Sarkikos, 09 February 2024 - 10:22 AM.


#21 Sarkikos

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Posted 09 February 2024 - 12:48 PM

I just received an email stating that my order for the Antares Variable Barlow has shipped.   Apparently, they sent it out before heading to the star party in Florida.  :grin:

 

Mike



#22 eyeoftexas

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Posted 09 February 2024 - 01:05 PM

I just received an email stating that my order for the Antares Variable Barlow has shipped.   Apparently, they sent it out before heading to the star party in Florida.  grin.gif

 

Mike

Looking forward to your field report.  


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#23 Second Time Around

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Posted 09 February 2024 - 04:33 PM

I made one of these some 50 years ago to fit 0.965 inch eyepieces using a 1.25 inch Barlow some aluminium tubing and Scotch tape.

 

Thus begun my love of zooms. It was the reason why on my second time around that the first eyepiece I bought was the Baader zoom and matching Barlow.

 

The advantage of the Antares product is of course that the amplification can be varied without replacing the Barlow with a different one or changing tubing.

 

However, with more experience I can now determine which of the several Barlows I own is the best for the objects I'm observing and the conditions on the night.  So I rarely have to change them anyway.

 

That said, I can see a market for this sort of product.  However, this Antares one is expensive at $100 - way more than their standard model at $40.


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#24 Mike B

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Posted 09 February 2024 - 05:40 PM

 

…. However, this Antares one is expensive at $100 - way more than their standard model at $40.

They use the very best Scotch tape!


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#25 rgk901

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Posted 09 February 2024 - 05:56 PM

I use the rings from colored filters that I dont care for to make an adjustable Barlow that I screw on to bottom of barrel... but it's more work than this Barlow.

Although this Barlow looks tall and with an added long eyepiece you may need a passport to get to the eyelense ;)

I saw this Barlow last summer and thought about buying it but the lenght scared me a bit...
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