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University Optics 2" 2x Barlow
Submitted: Friday, 23rd September 2005 by Dave Girling
For over 30 years I have been observing. I have had a lot of telescopes and accessories. In this review I would like to see how a 2" Barlow (not very popular) would work in my 10" F5 Newtonian.
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My 10" deluxe dob

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The eyepieces and barlow for this review

Now most people would not buy a $1k Telescope then buy $3k worth of eyepieces. I had a few eyepieces already before I purchased this scope .The eyepieces I use are:

  • TeleVue 31mm Nagler
  • TeleVue 12mm Nagler
  • TeleVue 22mm Panoptic
  • Meade series 4000 8.8 mm UWA

Now using these eyepieces on there own in a F5 scope at FL1250 is outstanding. But the 8.8mm only gave me 142x. I wanted more.

So I set out to buy a Barlow. I looked over the net and found fist of all 2" Barlow's are not popular. The main one out there is the TeleVue Big Barlow. At over AU$300 I was not too keen. So my search led me to a University Optics Barlow in the 2" range. They have 1.25" Barlow's also. The price was much better at AU$160 shipped to my door from Frontier Optics (many thanks to Daniel).

2" Barlow's are not common due to there weight and size. Most people say don't bother barlowing 2" eyepieces as it's too much glass, and there is a loss of light. We shall see if this is a problem!
 
Now with my 2" Barlow we get magnification at 2x putting the focal length of my scope from FL 1250 to FL 2500mm. So the eyepiece magnifications come to 31mm @ 80x, 22mm @ 114x, 12mm @ 208x and the 8.8mm @ 284x.

So I get higher power with my Barlow. This is my aim. But how does it really stand up under the Stars and Planets??

First the build quality of the Barlow is perfect 10/10 here. The box said made in Japan, if that means anything. It is heavy but not as heavy as a Powermate.  Baffled inside (nice surprise here) Anodized black. Very nice finish. Optics are coated and have a Green tinge to them.

TeleVue 31mm Nagler

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31mm Nagler with the 2" UO Barlow

So I will start with the Barlow and 31mm Nagler. This to my surprise is as good as it gets in my opinion. It was a surprise to see the images this sharp. This combination is very heavy and a counter weight is needed.  With power at 80x and a field at 1 degree I'm finding this combination getting a big workout on Deep Sky objects.

I would like to do a comparison with a 16 mm Nagler and hope to someday. Whether it is the Barlow which I say it is, stars are sharper using the Barlow than not. On axis is excellent so is off axis. There is a little purple colour on brights stars near the edge of field. At only the last say 10% of the field. Very slight sea gulling as well very close to edge of field. I only noticed this when I was really looking for it.

The background sky is nice and dark and image scale is very good. As the focal length is close to my old LX 200 10" it is worth noting in my opinion that Star images where sharper in the Newtonian Barlow combination. May upset some, but I found Stars where defiantly sharper in the Newtonian. Might I say more refractor like!!

This was a definite surprise. Without the Barlow the 31 Nagler is as most agree one of the best wide field eyepieces around. And gives a 2 degree field in the F5 scope alone. Awesome!! I do find thou I really like the Barlow and 31 combination. So the Barlow is a winner here.

TeleVue 22mm Panoptic

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22mm Panoptic with the 2" UO Barlow

The 22 mm Panoptic is a strange mix. Why barlow the 22 mm Panoptic when one has a 12mm Nagler? Basically the same thing and the Nagler has a bigger field.

Again I found the view very nice. Sky background was nice and dark and also Stars are very sharp. With the smaller field but keeping the big eye relief I really enjoyed the views. I found myself not pulling the 12mm Nagler out (no I'm not selling it!) and found around 70% of Deep Sky work so far done with the 31mm and 22mm. The 22mm is outstanding by itself in the scope, but imo is improved with the Barlow. Very nice on Globular clusters and Galaxy's.

TeleVue 12mm Nagler

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12mm Nagler and the UO 2" Barlow

The 12 mm Nagler Barlow combination is getting to the high power range @ 208x.

So this is what I use first when looking at the Planets. The eye relief on this eyepiece is huge and works well with glasses or not. The filed is big considering its working like a 6mm eyepiece. Again I found as before Stars sharp on and off axis. Sky background inky black.

Jupiter showed no sign of distorting at edge of field, some people think this important and more so in a non tracking scope. But I find I look into the middle of an eyepiece not at the edge!! Another good test is the Jovian Moons, as they fell into the field nice and sharp again. Not all was great here thou. I found the Moon being so bright it gave a few reflections. This I think was more reflection off my eye and in the eyepiece, maybe not so much the Barlow. Its was not bad but I could see it from time to time.

I did not get a chance to observe Saturn with this combination and very much look forward to it, and also Mars in the coming months.

Meade Series 4000 8.8mm UWA

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8.8mm Meade with the UO 2" Barlow

So onto the last eyepiece in the collection, the 8.8mm UWA. With the Barlow this gave 284x. This is the highest power I find I could use in my location where seeing is average most of the time.

Jupiter was a wealth of detail; the image scale was what I was looking for. I did not notice any ghosting or reflections.  The Moon of course was fantastic as it is in most scopes. It was nice to have a good field with such high power.

Conclusion

So the Barlow passed most tests as far as I was concerned. As for light and contrast loss due to all that glass in high end eyepieces and a Barlow, I find it hard to say. I would have to test an Orthoscopic eyepiece at the same time. I had Orthoscopic eyepieces once, they're nice but the field for me is too small. Sharp? Very much so. But better than the above combinations? That to me is debatable and more a personal choice.

At this price I think it is very good value. My only gripe, is that I would prefer a clamp ring instead of set screws. Also this Barlow does not come with a 1.25" adaptor as standard.

You could pay $300 plus for a 2" Barlow, but I don't see why. The University Optics Barlow is great value at its price.

Highly  recommended.

Review by Dave Girling (Dave47Tuc). Discuss this review at the IceInSpace Forums.
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