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Old Dec 29, 2009, 7:23 AM   #11
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If you are going with the 2 lens solution, and since the tamron 18-270mm is on your original list. You may want to look at the canon ef 70-300 USM IS lens. It is in the same price range. It is a bit faster then the tamron in the AF department.
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Old Dec 29, 2009, 8:33 AM   #12
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PS. I am also an amateur astronomer, so sometimes zoom gets the priority ..
No it doesn't. Sometimes telephoto (a long focal length) is important. The amount of zoom is simply the ratio of shortest to longest focal length.

e.g. 18-200 => 200/18 => 11x zoom.

But a 400mm lens with no zoom action at all i.e. 400/400 = 1x zoom.

Has a focal length twice as long as the 11x zoom. Do you see?
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Old Dec 29, 2009, 1:45 PM   #13
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shoturtle, You are right for Astro a Tripod is a Must.
Again, for wide field (like constellations etc) I am planning for the Canon EF 50mm f/1.8 II which seem to be good for this purpose... however for Moon, Jupiter, Saturn and the Sun I am planning for the Zoom Lens (that would be helpful for me this coming Jan for the Annular Eclipse, cause I cant carry by big and heavy 6" Newtonion).

I will be uploading some pics in my flickr page and will update with the link.... please check it out ........
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Old Dec 29, 2009, 1:52 PM   #14
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@shoturtle: hmmm ur suggestion of canon 70-300mm seems to be good with the two lens option ! Yes!

@peripatetic: My bad, I understand what you said.. and I should have said it as long focal length instead of zoom!...(what I meant was to have a long focal length lens just like you said)
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Old Dec 29, 2009, 1:52 PM   #15
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If you want to single out a single constellation, the 50mm may be a bit to wide. A zoom with 300mm far end will give you the ability to frame the shot better then the 50mm. The 50mm does do a nice job with a blanket of stars with the constellation.
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Old Dec 29, 2009, 1:57 PM   #16
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300mm isn't really going to do it for moon/planet shots. I would however love a camera mounted to the Newtonian.

Here are some recent moon shots taken with a 1680mm lens, 300mm really gives nothing usable.

Another bash at the moon
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Old Dec 29, 2009, 1:59 PM   #17
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Originally Posted by phani_astronomy View Post
@shoturtle: hmmm ur suggestion of canon 70-300mm seems to be good with the two lens option ! Yes!

@peripatetic: My bad, I understand what you said.. and I should have said it as long focal length instead of zoom!...(what I meant was to have a long focal length lens just like you said)
Since you are looking in a bit higher quality price range, the ef 70-300mm is usm would be my choice. It has serve me well when I was shooting film, and has function very nicely since I transition to dslr. And it seems to be the quickest of all the lenses in it's class, including the sigma and tamron.
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Old Dec 29, 2009, 2:05 PM   #18
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Originally Posted by Mark1616 View Post
300mm isn't really going to do it for moon/planet shots. I would however love a camera mounted to the Newtonian.

Here are some recent moon shots taken with a 1680mm lens, 300mm really gives nothing usable.

Another bash at the moon
I totally agree that the 300mm will be to short for the moon shot. I took this one the other day hand held, it pail in comparison to your shot with the custom super zoom set up.
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Old Dec 29, 2009, 2:15 PM   #19
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here is a crop shot, orginal was 1280x853. 300 is to shoot for much details.
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Old Dec 29, 2009, 8:54 PM   #20
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Finally here is the link there are few pics of mine which my friends took.. so dont consider those

www.flickr.com/phani_astronomy

shoturtle: As per my knowledge from my prev experiments (with Kit Lens), I suppose, the the 50mm should give me the ability to shoot constellations which are big (like the Orion, Big dipper, Taurus, Scorpio etc). However, let me check it out again...its been a long time since I took astro pics.

Mark1616: I looked at your "Another bash at the moon"; when photographing eclipses of Sun and the Moon, I am looking forward to get the same size as the very first pic you posted here.

I have spent good amount of time experimenting with Webcam-telescope and dslr-telescope combination on Moon and Sun, I will upload them too and share it with you guys...
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