Monday, October 15, 2012

Autumn ionisations

Milky Way is shining high in the sky during the autumn - depending of the time you can see Cygnus, Cassiopeia or Perseus constellations above your head. In these ones you can find massive amount of gas and dust clouds that form different nebulosities. Many of them are deep red hydrogen alpha nebulas or dark dust clouds that covers objects placed behind them. One of the well known nebulas is IC1805 in the Cassiopeia. It is also known as Heart Nebula. It is placed about 7000 light years away and it is formed by the ionised hydrogen excited to light by nearby stars. 

The star cluster inside is known as Melotte 15. In the picture bottom you can see one of its separated part that has been discovered in the first place and it is also known as NGC896. Upper part of the picture is occupated by the Soul Nebula (IC1848) that is also 7000 light years away. In these both nebulaes you can find many star clusters, but in fact in this sky region it is hard to faind a place wihtout them.
A little bit to the left in the constellation of Cygnus (The Swan) nearby its brightest star Deneb there is more famous nebula North America (NGC7000). It occupies upper picture part. Below there is Pelican nebula (IC5070) separated from North America with the visible dust line. Both these nebulaes are in fact the same ionised gas cloud and its distance from Earth is not well defined. Also the star that illuminates this cloud is not yet determined for sure - if it is Deneb, the nebulaes are about 1800 light years away.

Both pictures have been taken using modded Canon 20D camera using 200mm telephoto lens at f/5.6. IC1805 is a stack of 35x5 minutes exposures. NGC700 is 60x5 minutes stack.

Clear skies!

No comments:

Post a Comment