Image of the day

Hi,

I have tried to take so pics using a vesta webcam and I realized that the magnification was much higher than when I try using a 35mm camera. I believe that this difference may be related to the size of the 35mm frame and the size of the vesta ccd. How can I calculate the magnification using the vesta webcam ? I have used a 7" f/7 in prime focus technique.

Thanks,
Andre

July 15, 2004 10:10 PM Forum: Telescope Making

How can I specify a secondary for astrophotography

Posted By Andre Moutinho

Hi,

I intend to build a 7"f/5 or 5"f/5 scope in order to make astrophotos. I would like to know how do I calculate the secondary size in order to use a 35mm camera. What about a vesta webcam ? The secondary specification is the same for both cameras ?

Thanks,
Andre

July 15, 2004 10:11 PM Forum: CCD Imaging and Processing/Solar System

What is the focal ratio limit for Astrophotography

Posted By Andre Moutinho

Hi,

What should be the lower f ratio for astrophotography usage without the comma corrector? F/5 ? There exists differences in comma between a 35mm and a webcam ? I believe so.

Thanks,
Andre

July 15, 2004 10:23 PM Forum: Chinese Optics Imports

When the APO 93mm lens reviews will be available ?

Posted By Andre Moutinho

When the APO 93mm lens reviews will be available ?
Does anyone know ? And what about the UWA ep series ?
Bill promissed pin point star images at the edges
down to F3.5. Is it reasonable for a such low cost ep ?

Thanks,

Andre

July 17, 2004 04:19 PM Forum: Telescope Making

dob altitude disk size

Posted By Andre Moutinho

Hi,

I am about to build a dob mount for a 12.5" f/4.7 tube newtonian. What should be a good altitude disk diameter for this scope size ?
Thanks,
Andre

July 17, 2004 04:52 PM Forum: Equipment Talk