IC1396 Nebula - December 2013

About the image…

Image title – IC1396 Nebula.
Taken at – Observatorio del Teide (Tenerife – Spain; 16º 30' 35" W, 28º 18' 00" N).
Telescope – Takahashi FSQ-106ED, f/3.6.
Instrument – SBIG STL-11000 CCD camera.
Exposure –  Thirteen 900s images in Hydrogen alpha.
Image size – 5.1º x 3.2º.
Images taken and reduced by –
 Jorge A. Pérez Prieto and Pedro A. González Morales.
Text  Jorge A. Pérez Prieto and Pablo Rodríguez-Gil.

About the Object…

This large nebular complex is some 2400 light years away in the constellation Cepheus, just within the Orion Arm of the Milky Way. The nebula is a huge hydrogen cloud that amounts to about 12000 solar masses. Atomic, molecular and ionised hydrogen are found in almost the same proportion. The main ionising source is HD 206267, a blue giant star with spectral type O6.5 located close to the centre of the nebular complex, which can be easily spotted in this months AIM.

Another highlight of this hydrogen cloud if the Elephant's Trunk Nebula, just to the right (west) of the 'central' star. It's a bright, dense region where many young stars, less than 100000 years old, are being formed. They were recently discovered in infrared images.

The bright star to the north (up) is μ Cephei, also known as Herschel's Garnet Star due to its vivid red colour. It's actually a red supergiant star found at 6000 light years from Earth. μ Cephei is among the largest stars known in our Galaxy, and the biggest one visible to the naked eye.

This months picture is a B&W image. It was taken through an H-alpha filter that only transmits light with a narrow wavelength range centred on 656 nm. This matches the nebula's main emission light, boosting the contrast of the image and highlighting small-scale details.