From: Mark Gaffney <markgaffney@me.com>

Date: February 11, 2010 2:21:33 PM MST

To: astro_IIDC@yahoogroups.com

Subject: M 42 &  SkyTools..

Here`s the prognosis for M 42 for tonight on SkyTools 3 Pro`s exposure calculator given the Scorpion at 1600 x 1200 pixels & beginning after Orion has passed the meridian (when I usually start..)This is with "Quality photometry" or SNR of 100...

Poor photometry or SNR of 25 requires one exposure of 7 minutes & over on the right you can see that an exposure of 35 minutes will give a SNR of 46...?

My next step will be to progress hopefully to guiding?! I wonder though what sort of exposure`d finally give some sort nebulous detail with this camera...?

Mark.