Nightscapes & Deep Sky Colors

Astrophotography Brian A. Morganti

M42 - Orion Nebula 

NGC 1973/75/77 - Running Man Nebula


click for full resolution image (1900 x 1345 - 285kb)


The Orion Nebula complex is undoubtedly one of the most famous and beautiful areas of the entire night sky. It is easily visible to the unaided eye from a dark location as a patch of brightness surrounding Theta Orionis, the middle star in the sword of Orion the Hunter, the constellation which dominates the winter night sky. Located about 1,350 light years away, the nebula glows red predominantly from the light of hydrogen gas excited by energetic newly formed stars in the heart of the nebula. It is the nearest star forming region to our own star, the Sun.  Viewed through a small telescope the Orion Nebula displays a greenish hue, the vivid colors shown above can only be revealed by long exposure photography using specialized astronomical filters.

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. 

The Orion Nebula contains a very young open cluster, known as the Trapezium due to the asterism of its primary four stars. The stars of the Trapezium, along with many other stars, are still in their early years. The Trapezium may be a component of the much-larger Orion Nebula Cluster, an association of about 2,000 stars within a diameter of 20 light years.  The Trapezium is also the source of great frustration to budding astrophotographers since it is usually one of the first objects they attempt to photograph.  The bright region of the Trapezium is often "blown out" in brightness in an attempt to resolve the finer details of the outer edges of the nebula (see image below).  The above image is a combination of various exposures in order to retain the stars of the Trapezium which can be seen full resolution by clicking on the above image. 

NGC 1973, 1975, & 1977 , just above M42 here, is a complex of blue reflection nebulae mixed with dark lanes and a touch of red emission nebulae. The blue color comes from reflected starlight scattered by dust. This beautiful nebula complex is often overlooked because of its spectacular neighbor, but is outstanding in its own right, being one of the brightest reflection nebulae in the sky.

North is up in this image.


  • Date & Location:  January 24 & 28th, 2012 - StormEffects Observatory - Bernville, PA

  • Weather:  Light winds, temperature average on both nights - 36F.

  • Sky Conditions:  Clear with average transparency on the 24th  - above average transparency 28th.

  • SQM-L: 20:25 average 24th - 20.38 on 28th (waxing crescent moon)

  • Optics:  TeleVue NP101is w/0.8x focal reducer (432mm f4.3)

  • Filter:  Hutech IDAS-LPS (Light Pollution Suppression)

  • Mount:  AP900GTO

  • Guiding:  Orion SSAG @ 5 second exposures

  • Camera:  Canon T1i (500d) Hap Griffin modified - Baader UV/IR

  • Exposure:  6 x 4 second subs, 14 x 1 minutes subs, 13 x 3 minute subs, 16 x 6 min subs @ ISO 400 (total 149 minutes)

  • Calibration Frames:  Master Dark & Bias 40F

  • Processing:  Images Plus 4.50b, PS CS6, GradientXTerminator, NIK filters  

  • Comments:  The four second exposures were taken to properly expose the 4 stars of the Trapezium...any longer and they quickly became overexposed and washed out.  The other exposures increasingly captured the finer filaments of the nebula's outer reaches.  The exposures were then each calibrated in Images Plus and brought into PS CS6 for processing.  These images were then brought back into Images Plus where they were aligned and combined using HDR stretching techniques.  Final processing was then accomplished  back in Photoshop CS6.  A few slightly elongated stars are the result of field rotation caused by less than perfect polar alignment.  I've since drift aligned to compensate for possible settlement of my permanent pier base. 



For Comparison below is my first attempt at imaging the Orion & Running Man Nebula



  • Date & Location:  October 21, 2009 - Bernville, PA

  • Weather:  Calm wind - 37F.

  • Sky Conditions:  Clear with average transparency. 

  • Optics:  TeleVue TV60is Refractor (360mm -f/6) with field flattener.

  • Filter:  Hutech IDAS-LPS (Light Pollution Suppression)

  • Mount:  Losmandy G-11 equatorial with Gemini V4

  • Guiding:  None

  • Camera:  Canon T1i (500D) Hap Griffin Modified - Baader UV/IR

  • Exposure:  26 min (4 x 4 min, 2 x 3 min, 1 x 2 min, 1 x 1 min, 3 x 20 sec) @ ISO 800, RAW

  • Calibration Frames:  In camera dark frame subtraction

  • Processing:  Photoshop CS4, Noise Ninja, NIK 

  • Comments:  This is one of my first light images that was tracked, but not guided.  Star Trailing resulted in part due to an off center polar alignment scope reticule and the need for Periodic Error Correction (PEC).



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