Hi All,
As the curse of all deep sky imagers is approaching (full moon), this is typically the time of the month I plan future deep sky acquisitions instead of collecting data (no point wasting my time in obtaining crap data). So during this period, I thought I’d share some data I acquired a while back for a stellar processing challenge. At the time, I could not think of a better challenge than a wide field version of the open cluster M7.
So, I have provided two versions of the R, G, B files (small and large).
The small is a crop of the cluster (16-bit TIFF files - around 5.2Mb in size each) and can be downloaded here;
Red (5.2Mb),
Green (5.2Mb),
Blue (5.2M)
The large is the STL11k full frame FIT files which are 42Mb in size. I’ve kept the data in FITs IEEE float format as some stars are greater than 65k pixel values (I think the R channel has a few 77k value stars). Providing the 16-bit FIT files would have possibly dropped the file size, but I'm not certain of your image processing routines so feel its best to give you the maximum dynamic range possible.
Red (42Mb),
Green (42Mb),
Blue (42Mb)
All frames are reduced (dark, flat, bias), registered and are a combine of 5x5min subs per colour channel (25min). They are ready for your processing pleasure.
I would recommend a starting colour ratio of R:1.5,G:1.0,B:1.5 if you want to get close to the correct colour balance.
I have no intentions to use this data for anything else. I was simply going to trash it. Put bluntly, it’s not the best data I’ve acquired. Stars aren’t perfectly round. Those who process the full frame fit files will see stars in the top left corner have elongated and you’ve got a reasonable gradient to deal with. I did say it was a challenge! What? You wanted magnificent data present to you on a silver platter? If it was that good, I wouldn’t be giving it away so easily.
So, don’t be shy – have a go.
There are no rules, just have fun and post your results and some info on what you did so we can check’em out.
Below you’ll find my first cut of the star field. These are low res because of the IIS upload limit. If you want to see a higher-res full frame version, you can click
here (3.1Mb).