Celestron Luminos Barlow - similar to TeleVue Powermate?

[jgroub]

Hi everyone, new guy here.  I understand that the TeleVue Powermate is not actually a Barlow in the strictest sense of the term, but instead is a focal extender.  The difference is that as opposed to just doubling the magnification, the Powermate also maintains the same eye relief as well.  

Some have pointed out that this eye relief issue can be a problem in terms of a regular Barlow in combination with an eyepiece that already has a long (20mm) eye relief.  The Barlow will make that eye relief somewhat longer, and putting your eye in the right place can then become a challenge.  The Powermate seeks to eliminate this problem entirely by having four elements instead of the usual two (or three in an apo Barlow).  

Well, the Celestron Luminos Barlow has 4 elements as well, and is about half the price of the Powermate (at least here in the States, that is).  Does anyone know if the good folks at Celestron were trying to achieve the same idea as the Powermate by going to 4 elements?  And, more importantly, did they succeed?

I've seen the Powermate referred to as being so good, it's as if it isn't even there, because it's just so "clear."  It just goes about and does its job of doubling the magnification, and doing absolutely nothing else.  How good is the Luminos compared to other Barlows/focal extenders, including the Powermate?  

Thanks.  

[John]

Hi and welcome to the forum

I can't comment on the Luminos Barlow I'm afraid as I've not used one however I have owned a couple of Powermates and have compared their performance with the Explore Scientific Focal Extender and the Meade TeleXtender and found both those latter devices offer very similar characteristiscs to the Tele Vue Powermate. They might be worth considering if the Luminos Barlow is not quite what you want.

It's interesting that Celestron still call their device a barlow. You might have thought that, had they adopted a Telextender / Powermate type optical layout and characterisics such as not affecting the eye relief and focal position of the eyepiece, they would have acclaimed this in the naming of the product ?. Manufacturers are not usually shy in proclaiming such things !

[rwilkey]

Hi have the ExSc Focal Extender and it is very good in my opinion, and quite a bit cheaper than the TV.  I would think this is a better one though I have not tried the Luminos.  I think it is sometimes a case of hedging your bets, at least it is with me.