NGC 40 (Cepheus)

Object image
Fig.1 - Weak in doubly ionized oxygen (O III): The unusually reddish planetary nebula NGC 40 in the constellation Cepheus, photographed with a 16-inch f/4.5 Dob on an equatorial platform.
Object name: Constellation: Coordinates: Apparent size: Visual brightness:
NGC 40 Cepheus 13h01m / +72°31' 1.23' x 1.23' 11.7 mag

The planetary nebula NGC 40 (also known as Bow-Tie Nebula or Caldwell 2) in the constellation Cepheus. NGC 40 is composed of hot gas around a dying star. The central star has a surface temperature of about 50,000 degrees Celsius and is approximately the size of the Earth. NGC 40 is roughly 3,000 light-years from Earth and was discovered by William Herschel in 1788 (source: Wikipedia).

Twenty-two 3-minute exposures (65 minutes total exposure) at ISO 800 taken on September 18 / 19, 2020 were added for this shot with the DeepSkyStacker software and the final image processing was done in Photoshop.

Equipment: Canon EOS 450D Baader modified 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).

Search chart
Fig.2 - Search chart for NGC 40. Map © 2020 "The Mag-7 Star Atlas Project", www.siaris.net. Map is slightly modified. The map can be downloaded here.