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Planetary with TOA130 and Barlow help.

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#1 andysea

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Posted 02 July 2013 - 10:16 PM

Hello, I'm asking for help choosing a good barlow. I would like to try my hand at planetary imaging. I have a Microsoft Cinema HD webcam that I modified for astro work a long time ago but never got to use. As an alternate I could use my Canon 5D II but I am not sure that it would be a good option.
My plan is to use the Tak TOA130 with a barlow to get a decent focal length. I was thinking a 3x barlow should give me an acceptable magnification but I am not sure.
Does anyone have any suggestion about a good barlow that will not introduce CA? I know next to nothing about barlow lenses.
Is my plan just so flawed that I shouldn't even try? I think most people use SCT's or very long refractors for planets.
Thanks in advance!

Andy

#2 BKBrown

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Posted 02 July 2013 - 11:45 PM

Your Tak will work just fine. I use a 4x Barlow with an f/7 scope (and have used up to a 5x Powermate depending on the camera), mine was made by Harry Siebert (4x, 1.25", w/centering adapter). I don't know your focuser, but you may also need a tube extension, I use one (from Stellarvue) with my TEC 140. Small bore LPI (lunar and planetary imaging with less than 6" of aperture) is a blast. Below is an image from earlier this year taken with my TEC 140, 4x Siebert Barlow, and a TIS DBK21AU618 w/ Baader UV/IR cut filter. Have fun! :grin:

Clear Skies,
Brian

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#3 andysea

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Posted 03 July 2013 - 10:42 AM

Great image and great info! Thanks Brian.
I will look for the same Barlow. Good reminder about UV/IR cut. I think I have one of those filters.

Andy

#4 RedLionNJ

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Posted 03 July 2013 - 12:04 PM

I suspect the seeing conditions on any given night may be more of a limiting factor than the relative quality of any Barlows. Or, on the (unlikely) bright side, maybe Seattle is significantly better than NJ. Many people don't appreciate just how important the seeing is (and how rare GOOD seeing is) until they try planetary imaging at decent image scales.

Good luck!

Grant

#5 andysea

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Posted 03 July 2013 - 01:12 PM

oh yes there's that!
we don't get very good seeing but I noticed that it varies a lot even within a few miles.






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