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Brief review - Antares 1.6x 2" Barlow


Moonshane

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I finally got a chance last night to try my new to me Antares barlow in my just completed 12" dob. I am not a fan of barlows generally but I am considering a couple of new eyepieces (20mm TV Plossl and 17mm or 16mm TV nagler) and it so happens that using this barlow with my 32mm TV Plossl which equates to 20mm and my 26mm Nagler which equates to 16.25mm may do two things 1) convince me that these focal lengths are worth getting or 2) that given the barlow, these focal lengths are not worth getting!

These barlows have long been hailed as a great addition to a wide field 2" eyepiece kit. In particular I knew of others that had used them with Nagler and Ethos eyepieces and at <£100 new it seemed too good to be true. However, despite the usual implications of this statement, the barlow appears to live up to its reputation.

My first mod was to change the metal set screws to nylon thumbscrews. preventing damage to the eyepiece nosepieces. The thumbs are very secure and work well. Newer versions of this barlow now have the twist lock feature.

The coatings on the lenses are very deep green and look well applied. The general bit and finish is very good albeit not quite Televue; eyepieces have a very reassuring solid feel when being slid in. Lens edges are blackened.

The scope being used was an f4 newtonian so I used my paracorr as I normally do for general observing creating a 1380mm f4.6. I used the barlow with the 32mm TV Plossl (giving 20mm = 69x), the 26mm Nagler (giving 16.26mm = 85x) and the 12.5mm BGO (giving 7.8mm and 176x). As I have to extend the paracorr about 30mm out of the focuser to achieve focus, I inserted the barlow into the paracorr and the eyepiece into the barlow. I don't know if it makes a difference but it didn't to the view.

One concern with barlows is that the eye relief of eyepieces used in 2x barlows approximately doubles. I have to say that with the Antares, and considering this was a fairly brief session, there appears to be no difference other than the higher magnification with this barlow. The views did not appear to suffer any flaws and the eye relief was apparently the same as without the barlow.

As you can see it appears to work well with a range of eyepiece types. Interesting on the thread linked to above, someone commented that the 1.6x factor is one often used to determine ideal eyepiece focal length progression so perhaps 32mm to 20mm to 12.5mm to 8mm to 5mm. This makes sense and seems to suggest why this barlow works so well and may have been a design consideration?

I am absolutely delighted with this eyepiece which was bought used for a snip and has changed my opinion about future purchases of approx £300. I'd thoroughly recommend it to anyone with a 2" focuser no matter what kit you have. If one comes up used then grab it. You'll either be delighted too or can sell it on quickly - they don't stay for sale long.

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in this case mate definitely. I think in my previous job I had a bit more money than sense and bought a lot of eyepieces I might not now buy. I have them now (and am glad I do) so will keep them but buying more takes more careful thinking and saving. this way I don't need to buy any more and I always thought that when on a tight budget, a barlow is a superb way to increase your kit, just one I had previously not favoured due to the above. that said, I did have a powermate for a while when building up my collection.

I the only criticism (which I didn't mention as it's not a criticism of this unit per se) is that it extends the eyepiece out a little more from the tube wall. when I get a chance I'll upload a pic with the paracorr, barlow and 13mm ethos - it's like a baseball bat!

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as mentioned above, one issue with using this barlow and say my 13mm Ethos on this particular scope is that for some reason (maybe as this is seen as an imaging scope perhaps) with the paracorr is the length of the optical train. it's not really an issue with this barlow but it's a consideration.

I am not sure why OOUK put the focus position so far out of the tube. perhaps it is to save materials (tube metal / length) or weight perhaps but bearing in mind the fact that the paracorr brings the focus point in by about 18mm and the barlow does a bit too, this is the approx focus position of the 13mm Ethos/barlow/paracorr to give an '8mm Ethos'. It's bordering on embarrassing and I can almost hear them at star parties already "you know what they say about people with such a long optical train....etc". In the dark might result in problems with hitting head etc. there's also some flex in even the great Baader steeltrack which is worrying. I might not therefore be using this with the Ethos. compare with the use of a 9mm BGO......

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  • 10 months later...

I have a 300mm f4 Orion Optics and a 26mm Nagler and always use a Paracorr. My question is whether using the Antares 1.6x barlow with the Paracorr needed you to change the setting on the Paracorr? Sounds a much cheaper alternative to a Nagler 17mm if funds are tight or you might use the higher power only occasionally. My other Naglers are a 13mm and a 7mm which makes a 2x barlow or Powermate less useful.

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I have the same scope, a 26mm Nagler and 13mm Ethos. in all honesty I'd not bother with the barlow as going from 26mm to 13mm is not a massive jump in a 1200mm focal length scope. in my case I spent another £50 on the used price and bought a 16mm T2 Nagler. This is on often overlooked gem and cost around £100 used. This, rather than the barlow would be my recommendation.

In answer to your question I read that putting the barlow in the paracorr and then using the usual settings worked fine.

I never really tried it in earnest as I quickly remembered the faff of changing out barlows and sold it. nothing wrong with it, I just am not a fan in general.

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Nice review Shane, Sometimes a quality barlow is tempting me as well in the back of my mind. I was thinking more perhaps along the lines of a 1.25 extender  in my case which would avoid the eye relief doubling. I don't think my pentax with 40mm eye relief would be comfy but it would give me a good 5mm eyepiece combo on the cheap perhaps. :)  something like this

http://www.explorescientific.com/focalextenders/

Not too expensive.

In all honesty I'd not bother with the barlow as going from 26mm to 13mm is not a massive jump in a 1200mm focal length scope.

Did you really mean that ?. Personally sometimes I find small jumps can make a difference, whether in my case it more due to the eyepiece characteristics, but a few weeks ago when looking at M46 for example and the PN together. At first I used my 28mm. The 25mm showed the PN that much bit better and stood out more, that is only a small jump in exit pupil, but it was enough it make worth while I found.  On that occasion I preferred the rendition of the 25mm BST in terms of tone over the MV as well, altogether a bit darker, but noticeable enough.  The 20mm was good too, altogether 3 eyepieces used on the same target that night, all worth it to show details in slightly varying degrees for me.

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hi Alex, I did mean it :smiley:


with my 12" f4, I find that unless I am observing planets, moon or doubles i often use just the 26mm for larger objects and finding objects and then switch straight to the 13mm Ethos. I'd think the effect would be the same with the 13mm T6 albeit with a slightly narrower field.


With my 16" scope there's a larger difference betwee the magnifications and field and with that I do tend to use the 16mm Nagler T2 I referred to above in preference to the 13mm Ethos on many nights.


Don't get me wrong, I have 25mm, 20mm and 15mm TV plossls and use these often, but generally in different scopes.


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Vive la difference I guess :smiley: . While the 25 to 28mm is very rare ( that eyepiece is mainly for my smaller 5 inch scope now) I do actually like having those two and the 25mm still comes out on occasion even in the 10 inch, partly because it accepts my 1.25 inch filter also.  If I had to live with my 15 BST and 28mm MV I'd feel I'd miss something.  The 28 to 20mm is a nice jump to have and I use it quite a bit.   It is not as if it is essential of course and I could live with 3 eyepieces if I really had to.  At the other end I find the 15mm is perfect for smaller clusters where the 20mm gets a bit wide, but also it has a very different tone/tint and characteristic in the way it renders the background and stars to the 20mm MV,  I like having those options.  

Or may be I am becoming a bit of focal length/exit pupil junky. :smiley:

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One of the things I noticed about 82 and 100 degree apparent field eyepieces at medium and low magnification ranges is that you seem to be able to get by with less of them. My medium to low powers go 8mm - 13mm - 20mm - 31mm. The last one is an 82 degree and the others 100.

It's difficult to explain why this is but perhaps it's just as well as ultra and hyper wide costs more dosh !

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don't get me wrong, as I say I have 13 eyepieces myself but just felt that in this case, purchasing the barlow is not necessarily the best option when you could get a 16mm T2 for not a lot more - that was actually my main point above rather than not needing anything in between.

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Thanks for this debate.. It's helpful to hear other people's experience. Nagler's are not cheap and with the 28mm-13mm-7mm set on my 300mm f4, and given a preference for looking at DSOs, a 17mm 2" looks an attractive proposition- but not if I'd often be jumping straight from the 28 to the 13.

A Nagler 16 is cheaper, but the type 2 is presumably not a current model and I could only get it 2nd hand .. One was on eBay but the sale was ended! The new 16t5 seems cheaper than the rest of the range, presumably because of the smaller eye relief?

Perhaps with our English skies I might be better getting something inbetween the 13mm and 7mm, for planetary viewing to get a liitle more magnification than the 13mm (108x with Paracorr) for the many occasions the 7mm gives just too much magnification (200x with Paracorr) as I look at my object dancing around in the viewfinder. (I hear that we can sometimes use too little magnification for some DSOs so might this option also help with DSOs also?)

I could always plug the gaps with TV plossls but I don't have computer guidance and a wide view is nice.

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