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Old 10-07-2006, 09:54 AM
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OneOfOne (Trevor)
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Barlow hardware for imaging with 350d

Hi guys,

I am hoping to get into imaging in a year or so, for the moment I am happy to do visual stuff. I am looking at buying a "quality" barlow in a few days and was thinking I should see what would still be useful for imaging. I am thinking of going down the track of using a 350d as it seems to be very popular and so many others are happy with the results. I may start with a DSI I, which I can use later for autoguiding, so would a 5x be more useful for this as well rather than 2x?

Anyway, what sort of magnification would you recommend? 2x or 5x?

If I get a 2x I was thinking of Celestron Ultima, (seems to have a good reputation) or maybe a TeleVue 2.5x power mate, or something like that.

If I get 5x, maybe a power mate? Of course, it needs to be usable for visual work in the mean time. It will need to work with Pentax/Nagler eyepieces.

My budget is of the order of $300.

So those who use a 350d, would a barlow of some sort be a purchase I can make now that will be useful later? Or are most images taken without some form of "magnification".
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  #2  
Old 10-07-2006, 10:55 AM
gbeal
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Hi 1of1
not sure if you need one.
Let me put it this way. For planetary, and some lunar imaging you need either a 5x or sometimes slightly less (not sure of the native focal length of the CNGT, but I suspect about 1000mm??).
BUT....... if lunar/planetary imaging you will tend to use a ToUcam or similar, not the 350D. While there is no reason why you can't use the 350D, I reckon a few attempts will point you in the direction of a ToUcam.
For DSO imaging you will likely need to "go the other way" and use something like a focal reducer/field flattener/coma corrector. This is where the 350D is a winner.
So it depends on what sort of imaging you were thinking of.
Gary
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  #3  
Old 10-07-2006, 12:21 PM
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Striker (Tony)
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I agree with Gary,

I actualy tried to use 2" 1.6 X barlow on my ed80 to increse the focal length from 600mm to just over 900mm and found even with only 1.6X I didn't have enough outward focus to achieve focus....I imagine the 2x would be even worse...this was tried with the DSLR.

I dont think you will ever have any use for a barlow and DSLR combo.
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Old 10-07-2006, 01:00 PM
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[1ponders] (Paul)
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As Gary and Tony have said, in this day and age of digital imaging the old barlow and slr have gone by the wayside. The only imaging you would do with it would be solar, lunar, Venusian, Jovian and Saturnian. They would be about the only objects bright enough, and you wouldn't get much image scale of the planet with that setup anyway.

If you have a look at the images. The first is Jupiter at around 2000mm focal length through a 35mm slr, the second is 1000mm focal length prime focus and the third is with a 2X barlow. As you can see you can do moon shots np, but Jupiter is far from exciting
Attached Thumbnails
Click for full-size image (IMG_0549 (Small).JPG)
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Click for full-size image (Photo 003 Moon 5 days old PF.JPG)
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Click for full-size image (Photo 04 1 day Past Qrtr  Neg Proj F2900 f29 Exp 1-15 Reduced.jpg)
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  #5  
Old 11-07-2006, 08:12 AM
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OneOfOne (Trevor)
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Thanks for the comments guys, I think I will choose a Barlow/Powermate to complement the eyepieces then, 2x or 2.5x, and not expect to be able to use it much for imaging in the future, I was thinking of 5x.

I assume, therefore, that most of the 350d stuff is taken at prime focus?
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  #6  
Old 11-07-2006, 08:16 AM
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[1ponders] (Paul)
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D/film SLRs come into their own for DSO and widefield imaging, either prime focus w/o a focal reducer or piggyback.
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