Archive for September 1, 2018

Planetary Nebula NGC 6818 “The Little Gem” and Galaxy NGC 6822 “Barnard’s Galaxy – Sagittarius

September 1, 2018

The September 2018 Observer’s Challenge object is PN, NGC 6818.  Several observers have already observed this beautiful and easy planetary.  It’s interesting to note that Sue French covers this planetary in her latest column. (Pages 54-56, DSW’s)

“… the Little Gem, NGC 6818 in Sagittarius.  John H. Mallas claims credit for its name and writes, “Of all the planetaries in the heavens, ‘the Little Gem’ is probably the bluest.  Its color is beautiful, and I have yet to see an artist’s paint to describe the color.”  (The Review of Popular Astronomy: June/July 1963)

When my brother bought a 60 mm f/15 EQ refractor in ~1962-63 (the telescope that spawned my life-long interest in astronomy)

My brother also had a subscription to “The Review of Popular Astronomy” and with this magazine, gave me some valuable information on amateur astronomy.  

However, it would be about five years later before I would begin to effectively use this small refractor at 14 years of age.  The fall of 1967, was my official starting point as an observer.  It was this year that I gave my first astronomy presentation to my 8th grade science class.   Roger

Using PN, NGC 6818 to locate NGC 6822, Barnard’s Galaxy:

NGC 6818 is also a great starting point to find the “most difficult” NGC 6822, known as “Barnard’s Galaxy.  So when you are observing NGC 6818, consider giving galaxy NGC 6822 a try.  This galaxy has always been a tough object for me. 

It was ~30 years ago when I first read about NGC 6822 in Burnham’s Celestial Handbooks: 

“….and was discovered by the sharp-eyed E.E. Barnard telescope with a 5-inch refractor in 1884.  For the small telescope it is not a particularly easy object.  though its visibility depends chiefly upon the darkness of the skyand the type of telescope used.  Hubble found it “fairly conspicuous” in a short focus finder with a low-power ocular, but barely discernible at the primary focus of the 100-inch.”   BCH Volume three, Pages 1616-1619 

Interesting and coincidental:  Also in the October S&T, Peter Tyson; discuses NGC 6822, Barnard’s Galaxy.  “The Big Empty” P-4, a lonely outpost between the Milky Way and the Local Void.”

NGC 6822 (Barnard’s galaxy) in Sagittarius:


It should also be noted that a very low surface brightness, extended object can often times be better observed at low magnification with a small refractor.  A good example of this would be NGC 6822 (Barnard’s Galaxy) in Sagittarius.  

“A weak glow but definite glow in 6 cm, where it appears elongated N-S and shows a very slight central concentration.  In 25 cm motion of the field helps in showing the low surface brightness galaxy, but it is difficult and ill-defined at best.” Observing Handbook and Catalog Of Deep-Sky Objects by Christian B. Luginbuhl and Brian A. Skiff.  

Finally…after almost 25 years (many years I attempted with my 10-inch reflector) but had never been successful.  In September 2014, I was able to sketch and make notes of this elusive galaxy, NGC 6822, using the 102 mm refractor.  Much of my problem has been due to light glow from a pesky unshielded street light in close proximity to my backyard.  A dark sky is critical for locating and observing this faint low surface galaxy.  So…..another difficult object checked off my list. 

The following sketch was made using a 102 mm refractor, a blank 5 x 8 notecard and a No. 2 pencil with the colors inverted using a scanner.

Rogers NGC-6822

The following image by James Dire of Hawaii using a 190 mm Orion Maksutov-Cassegrain telescope.