Tuesday, October 22, 2019

#236 - Monday, October 21, 2019 - Long Exposure

I got outside a little after 8 PM, took the cover off the scope and connected my tablet to the USB hub and to power, and then re-focused after focusing on the Moon in the morning.  (I know it doesn't make a ton of sense because the moon should be at infinity focus as well, same as the stars, but it has been my experience that solar system objects and deep sky objects have different focal points.  I'm not sure why that is.)

Things ran quite smoothly that night.  I set M31 to not start until it was 13 degrees past the meridian, and that seemed to get past the rough patch, I guess.  I still didn't get a chance to take a look inside the mount for the lagging in RA that M42 was doing, so that one didn't turn out.

In addition, NGC 2174, the Monkey Head Nebula, was out of focus due to the focus drift with temperature that Takahashi refractors are known for.  Rawr!

Onnnn the other hand, even though it was out of focus, the 10-minute exposures of the Rosette Nebula I tested that night came out round!  I didn't keep them unfortunately to show, but this is very exciting.  It really opens up the door for more narrowband imaging in the future of a wider variety of targets if I can hit those kind of exposure times.  In addition, it's very promising for putting longer focal length scopes on it and still being able to get 3-5 minute images.  I have my 8-inch Schmidt-Cassegrain that's 2000mm long, compared to 530mm of my Takahashi (although I'll probably be running it with a focal reducer to drop it to 1260mm so that my off-axis guider can find a guide star, and I can take shorter exposures).  I also have my new-to-me Newtonian f/4 astrograph that's 800mm long from my astro-buddy Rikk, which I'm quite excited to use as well.  I'll probably put the C8 on in the springtime for galaxy season.

Another piece of excitement for the night came early in the evening with the Pacman Nebula.  I was watching exposures come in from indoors, and I saw that an airplane had gone through one of my images.  Upon closer inspection, I saw a really cool phenomenon that I hadn't yet caught in one of my own images!

As you've undoubtedly seen on airplanes, there's a strobe that flashes every second or so.  It must be a very fast strobe because it lit up the jet engines for a short enough time to "freeze" it in the frame!  Super super cool. :D  Fortunately, it should process out with pixel rejection and averaging in the stacking process.

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