Monthly archives: February, 2016

NGC2237 Rosette nebula

Another place where the stars are born is called Rosette nebula. It is a cloud of hydrogen gas, located 5000 light years from Earth in constellation Monoceros (unicorn). The diameter of this nebula is 50 light years.

This time I processed collected data by two different ways. Basic data are three monochromatic pictures captured through narrow band filters: Hydrogen alpha, Oxygen OIII and Sulfur SII.

First technique is called Hubble pallet – natural color of H alpha is red, but it’s inserted into green channel, oxygen is blue, therefore ends in blue channel and sulfur is even more “red” than the red color, therefore lands in red channel. After many different post-processing steps the final picture looks like this:


Second technique is more realistic for the human eyes and brain, and requires pixel math. H alpha is red, SII even more, therefore the combination of this pictures (SII + 0.8*H alpha) will end up in red channel. Green channel is a combination of 0.075*H alpha + OIII. Finally blue channel is just OIII.


I am quite curious which picture you like more…

B33 Horsehead Nebula

Horesehead nebula is a dark nebula located in constellation Orion, approximately 1550 light years from Earth. The bright star is on the picture is called Alnitak (eastern star of Orion’s belt). Horsehead shape is a cloud of cold gas, blocking the light coming from ionized hydrogen in the background.

This nebula is my favorite, but it’s not so simple to photograph, due to its dimness. Even with very fast telescope (f-stop 2.8) I had to use quite long exposure times – 6 minutes. The picture was postprocessed by bi-color technique, which means putting 27 H alpha pictures into red channel and 17 OIII pictures into green and blue channel. This was done in Pixinsight software.