I got a little time and processed another image this weekend. I decided to process an image from the Sharpless catalog that we gathered data on in October and early November.
It is an image of SH2-108:
SH2-108 in the HST palette.
This image was composed using the Hubble Space Telescope (HST) palette which is a false color method of producing a picture. This is also often referred to as narrowband imaging because only a narrow part of the visible electromagnetic spectrum is used.
The data is acquired using three different emission line filters, this means that each filter is tuned to allow only the light from a particular element through. In the case of this image the filters used allow Hydrogen-Alpha, Oxygen III, and Sulfur II to pass through.
The data from these three filters is then assigned to a color channel (Red, Green, and Blue) in order to make a color image.
There are many different ways to do this and process the data to achieve a particular look or result. I prefer the HST palette for my narrowband images and I often use variants of Bob Franke's technique to achieve an image I find visually pleasing.
One of the advantages of narrowband imaging is that you can gather data even when the moon is up and at its brightest. Since you are not imaging in the entire visual spectrum the moonlight does not interfere as much.
I still have a lot of data to process as the observatory has been working very well. A lot of it is narrowband so there will be many more posts like this one in the future.
Thanks for looking.