I failed to post this when I imaged Rosette again back in January. This very, very wide field exposure from my very bright Bortle 9 back yard in Allen, Texas. To put it in scale, the full moon will fit inside the white-ish part of the nebula at the center of the image. Hydrogen gas (red) surrounds the open cluster in the middle and trails off to the upper right where another large nebula resides. Enjoy!
The Great Orion Nebula is one of the first targets many astrophotographers image. I’m no different. Its also one that many revisit as they learn more. Again, I’m no different. This is my latest attempt at ending the insanity bred by this highly dynamic portion of the sky. From faint dust to naked-eye visible gas clouds housing hot, young star clusters, this one region of the sky has it all.
Telescope: Radian Raptor 61
Filter: Optolong L-eNhance
Acquisition Date: 2021/11/11 and 11/12
30 x 2 minutes
114 x 5 minutes
Endless hours of processing in Pixinsight and GIMP
Winter time brings some big emission nebulae to the night sky in North America. A recent favorite of mine is the Heart Nebula, also known as IC1805 or Sharpless 2-190. This nebula is absolutely massive. If you could see it with the naked eye, it would be about 9 times bigger than the full moon. Unfortunately it’s too dim to be detected by the unaided human eye. A camera can do the trick though. This image is about 6 1/2 hours of data, mathematically added together and manipulated to make what I think is a pretty picture.
A couple of things I finally imaged from the bright, bright backyard in Allen, Texas.
The North American Nebula (NGC 7000) is a heavily hydrogen rich emission nebula in the constellation Cygnus, near the tail of the swan shaped constellation in the northern sky. It’s fairly bright with an apparent magnitude of 4 but it does span a huge amount of space, about 2 degrees wide. It covers an area about 10 times the size of the full moon, like I said, really big. We can’t see it with our naked eye despite its size because that light is spread out over such a large area. The camera can pick up that light though since it can collect photons for practically an indefinite amount of time compared to our Mark I Eyeballs. This image was captured with my new 61mm refractor and my trusty QHY camera. Captured September 9, 2021 from Fredericksberg, Texas, a lovely little Dark Sky Community a bit west of Austin.
The new moon ahead of the 4th of July is a great time to start imaging Messier 16, known as the Eagle Nebula. A portion of this nebula was made famous by the Hubble Space Telescope‘s image of the Pillars of Creation which they imaged in spectra associated with Hydrogen, Sulphur and Oxygen. The “Hubble” pallet maps Sulphur to red, Hydrogen to green and Oxygen to blue. In reality the light emitted by sulphur is a dark red, hydrogen a brighter but still dark red, and oxygen pretty close to teal. I collected 7,000 year old photons on June 18 and 19 from my urban backyard in Allen, Texas deep within the Bortle 8/9 zone which is about the worst light pollution you can get. I captured this on my 8″ Schmidt-Cassegrain telescope with a dedicated astronomy camera using a filter specifically designed to help mitigate the worst of the light pollution.
Unfortunately as more LED street lighting is adopted the worse the pollution gets. There are LED lamp products on the market that help mitigate the polluting spectra from street and sign illumination but getting a city to adopt them is difficult at best. This site does a good job of explaining the hows and whys of LED light pollution and how some products can help minimize the awfulness of LED lights.
Without further delay, the Eagle Nebula in “natural” color.
One thing astronomy largely depends on is a dark sky. Light pollution is a real drag if you’re trying to photograph faint fuzzy things, which I happen to enjoy quite a lot. There have been ways to quantify the lack of light in the sky for years but I’ve not been able to put that all together until recently. A highly sensitive light sensor that is able to withstand full Texas sun is not a particularly easy thing to make on your home workbench if you want to be able to make actual, quantifiable measurements.
Recently I’ve added a Unihedron SQM-LE to my home base setup. I can now tell you *exactly* how crappy my inter-urban night sky is. Conversely I’m working on a project to measure how incredibly dark it is at Ft. Griffin State Historic Site. That effort will hopefully end with getting it listed as an official International Dark Sky site. The end goal is to give back to an organization that has given the amateur astronomical community quite a lot. In getting them listed I hope to give them the tools to educate others about light pollution and try to get the ball moving back toward protecting the night sky rather than corrupting it.
The Whirlpool Galaxy I took last month compared to one I took from this month. The only real difference is location. The one I took from home is in Bortle 8 or 9 skies here in Allen, Texas. Surrounded by 440 acres of 24×7 illuminated concrete inside a 2 mile radius doesn’t help one tiny bit. Fort Griffin State Historic Site is in Bortle 2 skies.
I’ve done very, very little processing on this but the difference between the two is striking.
If you care to look in more detail. Click to open in a new tab.
These two galaxies are believed to have “collided” about 100 million years ago. It’s one of the brightest galactic groups visible from here and was cataloged by Charles Messier from his observatory in Paris on October 13, 1773. The smaller companion galaxy was discovered in 1781 by Pierre Mechain and is recorded today as NGC 5194. Wikipedia
This was captured from my very heavily light polluted back yard north of Dallas, TX on March 31 and April 1, 2021 with my 8″ Celestron EdgeHD and QHY 168C camera. I had the software select the best 110 of 120 images to integrate and did a few tweaks in GIMP to get the image seen here. A very surprising result for me given the light pollution we have.
Two nebular regions know as the Tadpole nebula on the left and the Flaming Star nebula on the right. These two heavily hydrogen rich regions are excited by the stars near them and radiate light at a wavelength of 656.28 nm which puts it firmly in the red part of the spectrum. Portions of the Tadpole Nebula (named after the tiny tadpole looking structures in the upper left part of the main body of that nebula) radiates light at 500.7 nm in the blue part of the visible spectrum from the excitation of oxygen. The Flaming Star nebula on the right doesn’t contain significant amounts of oxygen so this region is strongly red but what it lacks in color variety it makes up with complex textures. This region is about 3 degrees wide and 2 degrees tall so this field of view. For comparison the full moon is about half a degree wide.