| Object name: | Constellation: | Coordinates: | Apparent size: | Visual brightness: |
|---|---|---|---|---|
| NGC 7293 | Aquarius | 22h30m / -20°50' | 16' x 28' | 7.3 mag |
The beautiful planetary nebula NGC 7293 ("Helix nebula", Caldwell 63) in the constellation Aquarius. The expanding gas shell ejected from an old red giant star was discovered in 1824 by German astronomer Karl Ludwig Harding. It is 655 ± 13 light-years from Earth and one of the closest planetary nebulae (source: Wikipedia).
Seventy-three 3-minute exposures (219 minutes total exposure) at gain 100, taken on September 5, 2021, September 7, 2021 and on August 4, 2022 were added for this shot with Astro Pixel Processor (APP) software and the final image processing was done in Photoshop. Darks, flats, bias and darkflats were used. In Switzerland, the Helix nebula doesn't rise more than 23 degrees above the horizon.
Equipment: Cooled ASI 2600MC Pro camera, TeleVue Paracorr Type II coma corrector, 16" f/4.5 "Ninja" dobsonian telescope riding on a dual-axis Tom Osypowski equatorial platform, Lacerta MGEN autoguider, Lacerta off axis system (field of view comparison: image of the moon with the same equipment).
