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Includes discussion of web cams and digital video imaging
I have everything...I think
Last post 04-18-2008 12:13 AM by Anonymous. 2 replies.
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  • 02-17-2004 01:46 PM

    Angry [:(!] I have everything...I think

    I have a digital Rebel on back order, I have photshop, telescope, registar, registax, motor drive and ambition. Anything else I need to assist in photos?

    I can't seem to get my collimation right though. That is driving me insane. I have been to every website known and simply don't understand the terminology yet. I know, another thread.

    Thanks always
  • 02-17-2004 02:33 PM In reply to

    RE: I have everything...I think

    Shield

    You may want to look at a monitor to use along with your Rebel. Spytown in NY has some of the best monitors. I have used a Marshall 4" color monitor along with my CP 4500. Under dark skies you can resove 3-4 Mag stars. And even for DSOs you can see what you have imaged once the card finishes processing it on a bigger 4"screen. You are able to control contrast, brightness, color and tint. All this really helps with pre-imaging or post imaging decessions regarding settings(shutter speed and f number). For brighter objects, Moon Jupiter and Saturn the monitor is very usefull in pre imaging focus. Check it out http://www.spytown.com/mar4higreslc.html

    Regards

    frank b
  • 04-18-2008 12:13 AM In reply to

    Re: I have everything...I think

    Might not be what you are looking for but here is what I know about the f/number as to astronomy. In my opinion the f/number (focal ratio) of any telescope tells two things about the telescope and that is it's intended purpose and it's photographic performance. The brightness of a star depends on the telescope's aperture not the telescope's f/number. All telescopes of the same aperture at any magnification will show the same visual brightness. There are many that insist their long focal ratio telescope gets higher contrast, this is not correct. A refracting telescope does have more contrast than any other because of it's optical system not because of the f/ratio. You can see that when you are comparing very well made and very well corrected refractors, you will see there is no gain in contrast regardless of the f/ratio of each telescope. Even if a reflecting telescope is well made and has the same size secondary mirror obstruction as another, it will have the same contrast regardless of the f/number of each telescope. All of the confusion and there is much on this issue, is because of the photographic use of the f/number. A faster f/ratio does mean brighter images on film but not in a telescope. Aperture not f/ratio is the important factor with a telescope. Some photographers have a great deal of trouble with this concept. The f/number of any objective lens or a mirror of a telescope has nothing to do with the visual brightness of an image, the bigger the aperture the better.
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