Iris Nebula

This is the Iris Nebula which I spent some 21 hours photographing over several nights in 2022 and 2023. All exposures were of 180 second duration and about half of all exposures were with the luminance filter, the rest with R, G and B filters. I used the “galaxy rig” for this object with the Celestron 8″ EdgeHD telescope. If you take notes of what gear you use and the rotation angle of your camera it is possible to add more exposures of the object in the days, months and years to come. The more light you collect the more details and less noise you will get in the image.

There are three main type of nebulae that can be identified:

1. Emission nebulae are clouds of high temperature gas. The atoms in the clouds are energized by ultraviolet light from a nearby star and emit radiation as they fall back into lower energy states. 
2. Reflection nebulae are clouds of dust which are simply reflecting the light from nearby star or stars. They are usually blue because the scattering is more efficient for blue light.
3. Dark nebulae are clouds of dust which are so dense that they block the light from whatever is behind.

The different nebula types often coexist as in this photograph where the main nebula is a reflection nebula but is surrounded by dark nebulae.