NGC 6888 NEBULOSA CRESCENT + Mirko Tondinelli + L-Ultimate

source:Optolongpopularity:680Release Time:2023-08-08


Image Credit: Mirko Tondinelli (Italy)


It is located 2.5 degrees southwest of the star γ Cygni, immediately west of a very rich star field, which includes objects such as M29 and IC 4996. The most intense part of the nebula is located to the west, and forms an arc extended more in declination than in right ascension; this feature has led to the nebula being called crescent, since it has a "hump" to the west, like the Moon in its crescent phase. To locate it, you need a telescope, even if it has a small aperture; with binoculars it is possible to barely glimpse it in clear sky conditions. It is a typical stellar wind bubble generated by a massive Wolf-Rayet star (HD 192163), which is located inside it; this star would also be responsible for the nebula, which would constitute the material of the outermost layers of the expelled star. This wind collided with the material ejected by the star as it reached the red giant stage, between 250,000 and 400,000 years ago, energizing it. The result is a gaseous shell and the presence of two shock waves, which then interacted with the surrounding dense interstellar medium. 


Technical data:

TS Photoline 115/800
Camera zwo Asi 2600MC
22 600" light
Optolong L-Ultimate 2" filter 22x600"
Gain 100 T 0°
Sensor temperature 0°
Pixinsight and Photoshop processing