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IC 2149
Planetary Nebula
aka PN G166.1+10.4, PK 166+10.1, ARO 23
RA: 05h56m23.9s Dec: +46°06'17" (Auriga)
Integrated Visual Magnitude: 10.6
Angular Diameter: 12"
Mean Surface Brightness: 15.7 Mag/arc-secē
Distance 5200 ly

Minimum requirements to detect: 4-inch scope under suburban skies


IC 2149 is a small, bright planetary nebula with something to offer in telescopes of all sizes.  At low magnification IC 2149 appears as just another 11th magnitude star, although experienced observers may be able to recognize something odd about it's color.   At magnifications higher than 120x a tiny, elongated disk becomes apparent, surrounding a bright central star.  At magnifications between 120x and 350x look for a quite striking "blinking" effect as you switch between viewing directly and with averted vision.  When viewed directly only the star is visible; when you look to the side a bit (averted vision) the egg-shaped nebula pops into view. 

Because the star tends to dominate the view, using an OIII filter can be a great help because it dims the star nearly to invisibility against the background of the nebula.

At higher magnifications the nebula takes on a bar shape and in larger apertures tiny extensions can be glimpsed off each end. 

I observed this one with my 18-inch f/4.5 and my log begins, "Pretty darned cool!" 

97x: Only stands out as a star of odd color.

270x: Fairly bright disk with bright central star.  A real blinker! 
Direct vision shows only the star, averted vision pops disk into view. 
The star somewhat dominates the view.

430x: A bar-shape becomes apparent around the bright star.  OIII: star
all but disappears.  The bar is flat on one long side and has a "bottle
nose" on at least one end.  Very cool!  This one's a keeper.


The field in an 6-inch f/8 at 50x.  North is down and east is to the right.
Millennium Star Atlas Vol I Chart 72
Sky Atlas 2000 Chart 5
Uranometria 2000 Vol I Chart 66
Herald-Bobroff Astroatlas B-05 C-04