11 images Cocoon Nebula
46 images M33 Triangulum Galaxy
43 images M77 Cetus A galaxy
29 images Rosette Nebula
28 images M42 Orion Nebula
All are 5-minute hydrogen-alpha filter images on my ZWO ASI1600MM Pro on my Takahashi FSQ-106N with my Celestron AVX mount. Except for M42, which is a repeating series of 15s, 60s, and 5-minute images so that I can properly expose the wide range of brightnesses, from the very bright core to the dim outer reaches.
You might ask yourself, "Why take H-alpha images of galaxies? I thought only nebulae had much H-alpha." While this is largely true, there are quite a few galaxies that are undergoing furious rates of star-forming activity, known as starburst galaxies. These subsequently have a lot of dense regions of H-alpha. Other galaxies, like M77, have large nebulous and dusty regions without necessarily being starburst galaxies. M33 is very close to us, and we can see several of its normal nebulae. I wonder if sky-watchers in M33 enjoy large beautiful nebulae in our galaxy?
M77 is very interesting in radio light too, being a very strong radio emitter known as a Seyfert galaxy. The radio source, discovered in 1952 and designated Cetus A, turned out to be a point-like source after investigation in optical wavelengths by the Hubble Space Telescope and the Keck 10-meter telescope, only about 12 lightyears across. Since then, it has been determined that the source is a supermassive black hole at M77's core, weighing in at 10 million times the mass of the sun. Surrounding the core are dense regions of star-forming activity, which I'm hoping to capture nicely in H-alpha.
Single, 3-minute color frame from my ZWO ASI294MC Pro, zoomed in
Post a Comment