Powermate vs. Barlow

[bartman]

Whats the diffrence between a Powermate and a Barlow?
For instance Tele Vue does a Barlow and a Powermate.
:confused2:
Bartman

[troypiggo]

Not to be a smart-alec, but check out hit #1 ;) :)
http://lmgtfy.com/?q=powermate+versus+barlow

Feeling lucky?
http://lmgtfy.com/?q=powermate+versus+barlow&l=1

Edit: sorry mate, just found that google tool and been itching to use it :)

[Merlin66]

I used TV Barlows for many years, and recently changed over to the Powermates. One of the best decisions I've made so far!!
The Powermate gives a much better image.
Also, the variable magnification you get when you change the back focus distance on a conventional Barlow is almost non-existant.
So for imaging, I'd certainly prefer to use a Powermate.
For the average visual observing an ED Barlow would do the job pretty well.

[Krumlov]

Quite and old thread but asks the question I want to know!

I own a GS-680 and am enjoying looking at the planets. I want to see them in more detail so I have another thread going about filters but I also want to know about Barlows vs Powermates. Most threads are talking about the powermate with repsect to astophotography but I am only doing visual observing. So what is the current school of thought? For visual should I buy a powermate? They are $199 vs not much for a name brand Barlow (or $119 for a Televue Barlow)!

The second question is if I should get a Powermate should I go for 2.5x or 5x. Bintel has them both for the same price?

Lastly I am assuming I will get a 1.5" as I have three EPs of that size and only one 2".

:thanx:

[ausastronomer]

If $199 wont break the bank I would recommend a 2.5X 1.25" powermate. They have several advantages over a barlow for both imaging and visual use. The purists will say they are not quite to the optical standard of the very best barlows (Zeiss, Astrophysics and TMB) and they aren't, but it's close. However, the advantages make them the best choice IMO. You get what you pay for most times and the 2.5X powermate IMO is well worth the extra cost over a cheaper unit IMO.

Cheers,
John B

[Harpspitfire]

i wanted a 2.5 powermate ($180USD) but didnt want to spend that, from my understanding the powermate loses X as you increase the distance, so with my 2" diagonal and webcam setup i wouldnt of got 2.5X anyway- more like 2.25X- i opted for the GSO 2.5X at $49 USD, its a 3 element APO barlow, i was worried about the super cheap price but ordered it anyway- im glad i did!!-it out performs my ultima 2X barlow, very well color corrected and sharper, so the powermate isnt even on my mind anymore

[Merlin66]

Using a traditional barlow at varying backfocus will give a significant changes in magnification...far more than you would have with a powermate......

[Krumlov]

Ok sounds good we have a store in Australia that is selling a "2.5x magnification, 1.25", fully multi-coated,3 element apochromatic" which sounds like the same one for AUD$49 so given your good review I think I will get one of those.

[Krumlov]

Sorry I don't know what this means could you elaborate?

[Merlin66]

As the distance from the lens in the barlow to the eyepiece (or camera) changes, so does the magnification. If you use an additional spacer to hold your camera the magnification could, say, go from x2.5 to x3.5....whereas with a powermate the magnification would remain the same ie x2.5
HTH

[Harpspitfire]

according to the televue site under powermate applications- as you increase the distance between the pm and ccd, the mag will decrease, it shows it drops as far 2X

[Merlin66]

At 100mm distance, you're correct.
A conventional barlow would probably would have increased from x2.5 to around x4....a big difference...

[bartman]

Thank you for the belated responses :) :)

[OICURMT]

I'm hoping someone can explain this... Given the following:

1) http://www.televue.com/images/TV3_images/Images_in_articles/PowermatePowerIncrease_sm.jpg

2) http://www.astro-nut.com/lunar-03feb09a.html



The last statement indicates that the lunar image was taken via stacked Powermates (2X & 4X). Can you take the chart from 1) and sum the magnifications for each Power mate (i.e. is the resulting image 6X)?

If so, wouldn't it best to have a 2X/2.5X and a 5X for "maximum" flexibility? If so, top surface from each to the next Powermate or as a total system?

OIC!

[Merlin66]

I think he used the 2" Powermates he had to hand.
The total magnification would be 2 x 4 = x8
Depending on the camera and the connection used...the back focus would be slightly different. TV provide direct T thread attachment adaptors for the Powermates.
The "best" Powermates will depend on your scope and the focal ratio.
Think about f25-f30 as being the "sweet" spot for imaging....so if you have a f10 SCT, a x2.5 would be good, but if you have a f5 system then an x5 may be better....
HTH