Archive for September 2012

NGC 6826 – The Famous Blinking Planetary – Observers Challenge – Including the Complete Las Vegas Astronomical Observer’s Challenge – Posted: October 20th 2012

September 28, 2012

NGC 6826, also known as the “Blinking Planetary” so called because when observed with direct vision the outer nebula appears to vanish, leaving only the central star.  When using averted vision, the nebula reappears.  This phenomenon can be seen in scopes as small as a 60 mm refractor.  When observed with a 10-inch reflector at 190x this planetary appears mostly round, grayish in color, and fairly bright.  The outer nebula is fairly thin with a translucent appearance, and uneven edges.  The 11th magnitude central star appears very bright, with either a 4-inch refractor or 10-inch reflector.  The following sketch was made using a No. 2 pencil, and the color was inverted using a scanner.    

Roger Ivester 

On Saturday night, October 13th, my husband, Roger asked if I would be a part of an experiment.  He was telling me about a planetary nebula that was named “The Blinking Planetary.”  He said that when looking directly at the object, the nebula surrounding the central star would disappear.  I am not a skilled observer, so he was interested in my perception of the planetary, so I agreed, however, dubious of the blinking effect.  The 10-inch reflector was already set up in the backyard and I used a magnification of 114x.

I looked into the eyepiece and could immediately see an object that was different from the other stars in the field.  It looked like a bloated star, and it had a subtle bluish tint.  I noticed the color difference  immediately.  Roger asked me to look from left to right and then look directly in the center.  Wow!  I was surprised to see the outer part of the star disappear, and then when I looked toward the edge, it would reappear.  The central star was pretty easy to see with both direct and averted vision.  I must admit this was a lot of fun, and I was pleasantly impressed with “The Blinking Planetary.”

Debbie C. Ivester  10/14/12

To read the entire Las Vegas Astronomical Observers Challenge Report…just click on the following link…