M42, the Orion Nebula, and NGC 1977, the Running Man nebula

© 2015 Kwang Lee

I had to devote several nights to getting the exposures to make this image. This was shot on the nights of Nov 24, 25, 30, then Dec 14 and 15. I used 31 x 15 min exposures, 46 x 5 min exposures, 35 x 2 min exposures, 35 x 15 seconds, and 35 x 5 seconds. That's about 13 hours of exposure. I actually shot about 17 hours of total exposure, but I only used the best 80% of the shots to process the image.

      Scope: Takahashi TSA102S w/Televue .8x focal reducer/flattener.

      Mount: Used AP1200.

      Misc: Guided w/Orion 50mm guidescope and QHY5II-L autoguider.

It's kind of a mandatory shot for any astrophotographer, but I wanted to do it because I knew I would get something worthwhile as it's so bright.

There are issues with the image. The darker dust structures around the edges of the brightest parts are noisy. I got those structures from those longer 15 min subexposures, but I think I need like 3-4 times the number of 15 minute exposure which means another 3+ nights of imaging this object. Getting extra 15 minute shots would increase the signal-to-noise ratio which translates into less noise and more structure.

I was sorta lazy with using layer masks (a technique in Photoshop) and some of the stars are not the right brightness (too large) relative to other stars.

Sharpness is an issue. Overall, I think the image is a little blurry - except near the core of the Orion nebula where the Trapezium is located (the tiny grouping of 4 stars near the center). And that Trapezium is weirdly detailed with respect to everything else.

The overall color is little garish to me. I know this object gets overly saturated by most people and I ended up doing the same thing.

Also, there is some curvature in all the corners, but most obviously in the upper right and left respectively. I've known about this for awhile, but I haven't bothered to address it. *I think* it's focuser tilt as the curvature seems to be different depending on the orientation of the camera. I also picked up some spacers to place between the flattener and the camera. If you look closely to the bottom edge, just to the right of the center you can see some artifacts from the constant parade of satellites I had to deal with. Actually the satellites aren't moving, there's a bunch of geostationary satellites that happen to be located in M42
Kwang Lee

The following was retrieved from Wikipedia, the free encyclopedia, at
on March 1, 2014

The Orion Nebula

"The Orion Nebula (also known as Messier 42, M42, or NGC 1976) is a diffuse nebula situated south of Orion's Belt in the constellation of Orion. It is one of the brightest nebulae, and is visible to the naked eye in the night sky. M42 is located at a distance of 1,344 ± 20 light years and is the closest region of massive star formation to Earth. The M42 nebula is estimated to be 24 light years across. It has a mass of about 2000 times the mass of the Sun. Older texts frequently refer to the Orion Nebula as the Great Nebula in Orion or the Great Orion Nebula.

The Orion Nebula is one of the most scrutinized and photographed objects in the night sky, and is among the most intensely studied celestial features. The nebula has revealed much about the process of how stars and planetary systems are formed from collapsing clouds of gas and dust. Astronomers have directly observed protoplanetary disks, brown dwarfs, intense and turbulent motions of the gas, and the photo-ionizing effects of massive nearby stars in the nebula. There are also supersonic "bullets" of gas piercing the hydrogen clouds of the Orion Nebula. Each bullet is ten times the diameter of Pluto's orbit and tipped with iron atoms glowing bright blue. They were probably formed one thousand years ago from an unknown violent event."

The license terms of this written work from Wikipedia may be found at

The Orion Nebula

Physical characteristics

Right ascension
Apparent magnitude (V)
Apparent dimensions (V)

Reflection and Emission
05h 35m 17.3s
−05° 23′ 28″
1,344±20 ly (412 pc)
65×60 arcmins

The license terms of this written work from Wikipedia may be found at

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