Caldwell 15 — Planetary Nebula in Cygnus
NGC 6826
About Blinking Planetary
Description
The Blinking Planetary (NGC 6826) is a planetary nebula in Cygnus, about 2,200 light-years away. It gets its name from a remarkable visual effect: when you stare directly at it, the bright central star dominates and the nebula seems to vanish, but with averted vision the nebula reappears.
Observing Tips
Easy to find in Cygnus. In a 4-inch telescope at medium power, try alternating between direct and averted vision to see the "blinking" effect. The nebula is about 25 arcseconds across with a bright central star. Best in summer and autumn.
History
Discovered by William Herschel on September 6, 1793. The blinking effect was noted by observers and gives this planetary nebula one of the most descriptive common names in astronomy.
Fun Facts
Hubble images revealed two red FLIER (Fast Low-Ionization Emission Region) structures on opposite sides of the nebula, jets of material moving at supersonic speeds away from the central star.
Observe
1Properties
Position & Identifiers
2How easy to spot?
| Telescope | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| 80 mm refractor 80mm refr. | Medium | Medium | Medium |
| 150 mm Newton 150mm Newt. | Medium+ | Medium+ | Medium+ |
| Celestron C8 (203 mm SCT) C8 203mm | Medium+ | Medium+ | Medium+ |
Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs
With O-III filter
| Telescope | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| 80 mm refractor 80mm refr. | Easy | Easy | Medium+ |
| 150 mm Newton 150mm Newt. | Easy | Easy | Easy |
| Celestron C8 (203 mm SCT) C8 203mm | Easy | Easy | Easy |
3Visibility
Set a location in User Settings to see visibility data.
4
Filter Response Guide
5
Eyepiece View
Blinking Planetary · 0.4′ · N up, E left
6
Best Magnification
Explore
7
Central Star
8
Surface Brightness
Discover
9
Light Travel Time Machine
10
Relativistic Travel
Community Photos (1)
Credit: Bruce Balick (University of Washington), Jason Alexander (University of Washington), Arsen Hajian (U.S. Naval Observatory), Yervant Terzian (Cornell University), Mario Perinotto (University of Florenc.... License: Public domain. (Wikimedia Commons)
Skybred Mar 2, 2026
Nearby in the Sky
Other targets within a few degrees — pan your scope a little and keep exploring.
Visibility scores assume a 150 mm Newton at Bortle 4.
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