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Barlow this!

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#1 Douglas729


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Posted 12 January 2013 - 01:06 AM

I've read many posts regarding binoviewer barlows being placed high, low and in-between the diagonal and eyepieces but why not this one?

(2) 1.25" GSO 2X Barlows removed from their barrels then threaded into each eyepiece for 1.5 times magnification @ $60 total.

I don't perceive a problem with back focus, aperture, vignetting etc. and I just did a daytime test with (1) RKE 28 and a local TV-Radio antenna-tower that was amazingly good.

Am I missing something with this excellent price/performance configuration?

thanks guys...

#2 johnnyha


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Posted 12 January 2013 - 04:50 AM

Two 28mm RKE's + $60 in barlows, is $60 more than two 18mm RKEs.

OK they don't make 18mm RKEs but you get the idea. :grin:

Actually it's an interesting idea but I'm not sure there wouldn't be issues with vignetting... :question:

#3 Eddgie


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Posted 12 January 2013 - 09:50 AM

Nothing wrong with the configuration I guess if you just happen to need that specific power.

But now you have two elements to fuss with rather than one. And if you need them to reach focus (the primary reason most people use a GPC or Barlow), now every time you change eyepeics, you have to move to untread two barlows and re-thread them?

There are far to many possible combinations to count, but what gets used is generally the simplist configuration, and since the primary reasn many people use GPCs is becuse that have to have them to reach focus, then a single GPC or barlow in the light path is the easiest thing to do for most people.

I have used the GPC in the Maxbrights after and before a diagonal, and I have used a 2" Barlow lens screwed into the nose of a diagonal and into the nose of the binoviewer.

All of these work, but the problem is that they tend to work best for a specific set of eyepecies or something.

This is why I think that Powerswitch systems are popular (though they did not work for my own purposes). They cut down on the fuss.

So if this configuration works for you, that is the important thing.

But as someone said, a second pair of eyepeices might do the same thing is you didn't need them to reach focus, but if you did, now you have to move them every time you change eyepecies.

#4 Douglas729


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Posted 12 January 2013 - 10:25 AM


I don't need a barlow often on the 40, 32 or 28 pairs but overall, it doubles your entire eyepiece collection with slight magnification differences and frankly, one gets pretty tired of throwing ANOTHER $100+ into your light bucket which forever seems the Black Hole of an astronomer's bank account!

i.e. I have no 1.25" eyepiece pairs below TV 20mm plossls-
1- Buy 2 new TV 15mm for $120+ ?
2- Buy a 2nd Hyperion 17mm for $130 ?
3- or add 1 Barlow to a TV 20mm and get 2 TV 15mms for only $30?

So I choose door #3 as The Price is Right.

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