Things You Can Work on When The Sky is NOT Clear

If you're new to Astrophotography and getting your equipment set up for a night of imaging, you've probably got your imaging targets planned and optimized to make the most of the night.  Unfortunately, the one major item that you do not control and does not always cooperate is the weather.  So what do you do when you are ready to get some imaging done but you do not have clear skies at night?  Here are a few things you may want to consider to still make it a productive night.

A good first choice is to take a healthy dose of calibration frames, specifically dark frames, and adding them to your dark library collection.  I normally use my dark frames for calibration on average between 3 to 6 months.  I've learned that using old dark calibration frames can cause serious artifact issues when you use this data to calibrate your light frames.  I make it a point to constantly update my dark library and I try not be forced to use dark calibration frames older than about 4 months.  There are always additional frames you can add for a range of exposure times; I currently have library files for 1 minute, 2 minute, 3 minute and 5 minute and generally for camera temperatures of -10 Deg Celsius.  If you're consistent doing this, you eventually wind up with an extensive library of frames to use which is good for processing your images.  Flat and Dark Flats can also be taken but usually you want to do these specifically before or after you’ve done your light images and you have not broken the image train.  If you are pretty certain that conditions will clear later in the evening, get these frames out of the way before your main imaging session; then you don’t have to worry about them later.

My options for spending the time you have waiting for skies to clear are;

1. Research other targets that you may be interested in for future sessions or as a backup to your current target if it moves out of position by the time skies clear.
2. Resolve a nagging equipment problem.  For example, for I spent time working on a collimation issue I had with my astro graph.  
3. If you have a partial sky where stars are visible, point your equipment at one and work on your guiding.  Connect PHD-2 and let it guide while you try and dial in parameters to make improvements.  You can also use the time to rebuild the PHD-2 Dark Library that this system uses for guiding.  

I’m sure there are a lot of other options and feel free to let me know some of your favorite things to do when you run into this situation.