Planetary nebula NGC
6826 in Cygnus
Description of NGC 6826 in
The Deep Sky Field Guide to Uranometria 2000:
- Irregular disk with very irregular
brightness distribution involved in a larger and fainter disk of smooth
- central star magnitude = 10.6
- Alternate name PK 83+12.1
This object is sometimes known as
the “Blinking Planetary” because, when viewed in small telescopes the nebula
tends to disappear when looked at directly, leaving only the central white
dwarf star visible. When the observer looks to the side and sees NGC 6826
with peripheral vision only, the nebula pops back into view. This is an
effect of the different sensitivity of the eye’s rods (peripheral vision)
and cones (central vision) to low light levels. The more sensitive cones
can pickup the nebula, but the rods can not. In larger telescopes, such
as Kopernik’s C-14 and 20 inch, the view is so bright that NGC 6826 doesn’t
appear to blink.
Note in the 2x enlargement on the
right the differing brightness of the components of this nebula. Also notice
the ‘jets’ that seem to come from the inner, portion of the nebula. This
is a common feature in some planetary nebulae.
- NGC 6826
- Other ID: PK 83+12.1
- Magnitude: 9.0 (visual)
- Constellation: Cygnus
- RA: 19h 44m 48.0s
- Dec: +50d 31' 00"
- Size (sec): > 25
- Classification: Planetary
nebula; irregular disk.
George Normandin, KAS
November 27th, 2002