[Author Prev][Author Next][Thread Prev][Thread Next][Author Index][Thread Index]

RE: [APML] OT: M109, NGC 2403 and other collaboration images

Hi Jason,

I'm not clear on your definition of oversampling?  Are you talking about oversampling seeing due to the pixel count of the FPA or grain of the film, or...?  A longer focal length gives you a narrower field of view. At 32" and assuming f/8, that's a focal length of about 6500 mm.  I could get the same thing on my LX90 with a 3.5x Barlow.  Assuming I had a fancy enough camera to give reasonable enough exposure times at f/35 (!) and that seeing was such that the wider aperture isn't gaining anything, are you saying the images would be comparable?

That's really just an advantage of the focal length, but not directly due to the wider aperture.  People get different apertures simply because the aperture is a by-product of the different FOV's.  In visual use, it's the other way around.  They look for the biggest apertures they can afford.  But for photography, what you really want is an f/0.5 system.  <g>    I think the basic question is this:  Is aperture still just important for visual use, and is the speed of the system (a.k.a. f/#) still just important for photographic use?  

Cheers,
-Jason


-----Original Message-----
From: astro-photo-bounces@seds.org
[mailto:astro-photo-bounces@seds.org]On Behalf Of Jason Ware
Sent: Wednesday, March 02, 2005 10:00 PM
To: Discussion of Film Astrophotography
Subject: Re: [APML] OT: M109, NGC 2403 and other collaboration images




Duncan Munro wrote:
> 
> Greg , hi.   I look at Jim Misti's images and I see a challenge, in
> several ways.  For starters, even though he has a 32" scope he can still
> only resolve to the limits of seeing which does (or not?),

One very big advantage of over sampling with longer
focal lengths...noise reduction. You can image process
out much more noise without loosing any nebular or
star detail.

-- 
 -Jason Ware 

 ---------------------------------------------------------
       VISIT MY ASTROPHOTOGRAPHY HOMEPAGE!!
    ASTRO IMAGES FOR DOWN-LOAD, TIPS, REPRINTS
         URL: http://www.galaxyphoto.com
 ---------------------------------------------------------
       My Other Hobby....High Power Rocketry 
      URL: http://www.galaxyphoto.com/rockets
_______________________________________________
Astro-Photo mailing list
Astro-Photo@seds.org
http://seds.org/mailman/listinfo/astro-photo
_______________________________________________
Astro-Photo mailing list
Astro-Photo@seds.org
http://seds.org/mailman/listinfo/astro-photo