Hi Patrick, That makes me feel much better. With my 10" scope, as Joe mentioned, depending on seeing, the moon, etc. my limiting magnitude for minor planet astrometry (even with a 6 minute exp) is just shy of mag. 19. It sounds like I can do a lot better with the 14". Now I just have to save up for it. BTW, for anyone interested the Edge HD's are discounted 10% during August! (That's a $1000 savings for the 14" Edge HD on a CGE Pro mount). But, I'm afraid that isn't long enough to help me. Thanks & clear skies, Dale. P.S. When I saw your message it made me a bit nervous so I looked for a limiting mag. calculator online. The one I tried was "visual" only. Using typical max pupil size, etc. it said that the *best* I could do with a 40" scope or 4000" scope was magnitude 17.5. Thank goodness for CCDs.
-----Original Message----- From: utah-astronomy-bounces@mailman.xmission.com [mailto:utah- astronomy-bounces@mailman.xmission.com] On Behalf Of Patrick Wiggins Sent: Wednesday, August 03, 2011 3:21 PM To: Utah Astronomy Subject: [Utah-astronomy] How low (Was: anyone going out tonight?)
Hi Dale,
20 is no problem. I've gone deeper than that before.
The run I was doing the other night involved short (30 and 60 second) exposures.
When working minor planets, especially NEOs like the other night, exposures need to be kept short so the target remains a point source and not a streak.
Clear skies,
patrick
Sent from my iPad
On Aug 3, 2011, at 14:06, Dale Hooper <Dale.Hooper@sdl.usu.edu> wrote:
This is kind of disappointing to hear Patrick. One of the reasons I'm saving up for a 14" edge HD is that I thought the limiting CCD magnitude would be more like magnitude 20.
Clear skies, Dale.
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