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Televue Powermate

aerohound73

By aerohound73
in Discussions - Eyepieces

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John

John

Posted
Posted

The use a different optical layout to a barlow lens, as do the Meade and Explore Scientific TeleXtenders / Focal Extenders. All these designs, and especially the Tele Vue, have the benefit of not moving the focus position of the eyepiece and not changing the eye relief. Barlows do both these things which can be inconvenient.

In the case of the Powermate's they seem to just add the boost to the magnification and leave no other hint they are in the optical path. The ES Focal Extender is very good at this as well.

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alan potts

alan potts

Posted
Posted

They get snapped up because they are one of the very best doublers or more on the market. They are superb with all eyepieces, I have mine in a scope now with a 9mm BGO in it looking at a semi day-light Moon. I have used a Meade Tele-extender, the 2 inch one for about 3 months, this was also extremely good and is in no-way second rate against the Televue. I am lead to believe the Powermate for photography are even better.

Alan.

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John

John

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In optical quality, is there any difference between the 2" 2x and the 1.25" 2.5x?

I've owned both although not at the same time. I used the 2.5x one a couple of years back with Naglers and TV plossls and it seemed to work just as seamlessly with those as the 2" 2x one did with the Ethos, from what I recall. The bottom lens of the 2.5x looked rather small to my eyes and I was worried that it would not show the full field of view with the Naglers but it had been thought through properly of course and there was no sign of it in use apart from the magnification boost.

I recently borrowed an Explore Scientific 1.25" 2x Focal Extender from Russell (russ.will) and it reminded me very much of the 2.5x Powermate. It probably costs somewhat less as well.

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alan potts

alan potts

Posted
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I think in general there has been a fair bit of copying of Televue product, one of the downsides of being so good. If I were going to set out to make something, or copy something dare I say, there is not a great deal of point in copying from the bottom of the market.

I am doing an in-depth look at the Pentax 5mm XW and the TV 4.5mm Delos, as well as a passing glance at the 14mm's from each camp, if you didn't have to refocus you could swear it was the same eyepiece. A site member did suggest the Delos were copies but I think he was only trying to wind me up.

Alan

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Delboy_Hog

Delboy_Hog

Posted
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I have compared the 2.5x PowerMate with 2x and 3x Meade TeleXtenders, and apart from magnification I see no difference in quality.

That's interesting Michael, especially given the price difference. I've heard a couple of similar reports. Was your comparison for observing or imaging? (Or both?)

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michael.h.f.wilkinson

michael.h.f.wilkinson

Posted
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That's interesting Michael, especially given the price difference. I've heard a couple of similar reports. Was your comparison for observing or imaging? (Or both?)

I have used them both for imaging and observation. The price difference is not huge, but it is certainly worth looking into the Meades (now sold as Bresser SA Barlows, and under the Explore Scientific flag in a different housing, I believe)

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John

John

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Shows how different eyes see things slightly differently :smiley:

I thought the Meade 2" 2x Telextender was good but you could tell it was in the optical chain as light scatter around bright objects increased slightly making, for example, faint planetary moons, slightly harder to spot. I also found a they introduced a small amount of off axis colour towards the edges of the field with ultra wide eyepieces.

The Powermates just "got out of the way" and only added the magnification, the image being identical (to my eyes) to using a "native" eyepiece of that focal length.

The Explore Scientific 1.25" 2x Focal Extender (the only ES amplifier I've tried) did do a pretty good job of emulating a Powermate I reckon. Whether the ES offering is related to the Meade one I don't know for sure. Perhaps it's (the ES's) coatings and / or baffling are a little better than the Meades ?

These are just my findings of course - "your mileage may vary" as the often quoted saying goes :smiley:

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