Sunday, December 15, 2019

#262 - Saturday, December 14, 2019 - Rain Rain Go Away!

Berkeley tricked me! When I was here in March for the graduate student open house weekend (aka, "Hey yo please come to our school" weekend), it was sunny and warm.  When I moved out here in August, it was sunny and warm.  And it was sunny in September, October, and most of November too.


Which, in the Bay Area, means clouds and rain.  On the other hand, there's no snow, and the temperature hasn't yet dipped below freezing, which is a nice break from the winters I experienced in the Inland Northwest and the Midwest.  But clouds and rain mean no astronomy! :(

After all the clouds and rain from the past few weeks, finally having a sunny day felt a little like the one hour every seven years that the clouds break on Venus in Ray Bradbury's short story All Summer in a Day.  

It was still cloudy after sunset, but I checked again after dinner, and it had cleared!  I had the Takahashi refractor on my Paramount MyT mount loaded with my ZWO ASI1600MM Pro camera with an H-alpha filter.  I was going to work on collimating the Vixen 8-inch, f/4 Newtonian under the stars using SharpCap's experimental tool, but I also wanted to relax a bit and watch some TV.  

Around 10 PM, I checked in on the imaging from my cell phone while I sat on the couch with my kitties, and I saw that my latest California Nebula image was out of focus!  The autofocus routine in Sequence Generator Pro is a little touchy, since you have to start out already quite close to focus.  Maybe I should try and train temperature compensation on my Robofocus focuser so that SGP can start off already clouds.  I didn't want to get up off the couch, so I turned on the Frame & Focus mode in SGP and took a few guesses on adjusting the focuser until I got it close to focus, and then let SGP run autofocus again.  It worked better this time, so the sequence got rolling again.  

My other two targets for the night were the Cone Nebula and Medusa Nebula; I have plenty of H-alpha on the Rosette Nebula, so I gave that time to the other two.  Unfortunately, as we inch toward Galaxy Season, there aren't really any H-alpha targets for the Takahashi's wide field-of-view after about 2 AM, so I had the sequence end about then.  The moon was too bright to collect color data, which would open up a few more latter-half-of-the-night targets.  I wish I had an H-alpha filter that I could put into my filter wheel so that I could do both in the same night!  

Looking at my data the next morning, some clouds definitely rolled through the Cone Nebula images, so I lost most of those exposures.  I got a few more out of the Medusa Nebula set, but there were some tracking problems that streaked the stars in those ones.  Maybe the guide camera was seeing some tree branches?  (It's not co-boresighted exactly with the main scope).  I should consider swapping the mount positions -- putting the AVX where the Paramount is, and the Paramount further away from the tree, especially since it should handle meridian flips better.  But then I'd have to re-align much work! 😒

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