A Night in Sagittarius

Every now and then we get a perfect evening, I mean a perfect night. The stars are steady, there is no wind, the crickets are chirping, and the sky is dark and clear. Last night was such a night, so it called out to me: GO OUT and IMAGE! That’s what I did.  After turning on the equipment and cooling the CCD to -10C (not all that cold given the 90F temps outside), the telescope had to be convinced to point in the proper direction. It somehow managed to get itself into a situation where due south was aiming straight down. Not good. After wrangling with that, biases, darks and flat field frames had to be taken. Sunrise had just taken place, so now it was time to wait for darkness.  I worked with my kiddo, Jren, to teach the basics of DSLR nighttime photography: bunnies, bats, then stars were the targets.  Now, with darkness in place, what to image?  Well, there are few constellations in the summer with as many cool objects as Sagittarius. At the heart of the Milky Way, there are plenty of open clusters, reflection and emission nebulae, and globular clusters to hunt through. I chose one of my favorites, the Omega Nebula. I call it the Swan Nebula, as, to me, it looks like an inverted swan in the telescope. It goes by many other names: The Omega Nebula, Checkmark, Lobster and Horseshoe Nebula… and M-17, or even NGC 6618. Take your pick. They all work.  The image below is the result.

This is a one-hour integration of M-17 through a narrow band Hydrogen Alpha filter using the robotic observatory’s 10″ RC telescope and STL-6303 CCD imager operating at -10C. Not bad!

M-17 Ha