Here you can download some of the unprocessed stacks from images shown in the gallery. No matter if
you so so to practice processing or to compare the data to your own result. Any non commercial or
educational use including prints for yourself is allowed. A donation via the PayPal button on the
start page is welcome. Any commercial use is prohibited.
Small objects have been cropped to save you from downloading useless data.
All my images have been well calibrated by flats. In many cases
it is sufficient to subtract a constant offset for the background. In some cases there is a linear sky background as well. If you use
PixInsight for processing use ABE with function degree 1 and subtraction. If you use PhotoShop or Gimp an use the histogram tool
in individual channel mode and push the low slider up until the red background turns into a slight greenish touch. Do the same with
the green low slider to give it a neutral gray or slightly blueish color.
In most images only a few stars are saturated. Saturated parts
in a DSLR image in general tend to have a color cast. You can remove it be desaturating the brightest stars before the stretch using
an appropriate mask or a selection by brightness.
Detailed information is provided an the respective gallery page which is linked here for each object.
This data are registered to the above OSC data. You can use them stand alone for monochrome Ha images or you can use them
blend them with the above OSC data. The field of view does not always match well, so you have to crop the images.
First load both, the OSC and the Ha data. Crop both in the exact same so that you get rid of black borders while the data are
still registered to each other.
For emission objects extract artificial luminance from the OSC data and stretch it. Stretch the Ha data.
Blend both using either a maximum or an weighted
average operation or a combination thereof. You may want to split the OSC data to channels and blend the red layer with Ha in the same
way. First combine the mixed red with the unchanged green and blue. Then apply the enhanced L using LRGB combination in PixInsight or
Luminance layering in Gimp or PhotoShop.
For galaxies split the color data to layers and add Ha to red as described above. There is no need to add Ha to luminance. Some like to
assign a bit of Ha to blue as well. While this is a good idea in general it is not necessary here. The OSC camera usually picks up a lot
of blue in the star forming regions so that the result already is quite pinkish even without adding extra blue.
The data has been imaged with a mono converted DSLR. This kind of modification is very rare because it is a great effort and there is
a high risk of breaking the sensor. I had the work done by an experienced professional. Compared to a cooled astro camera the data is
very noisy although calibrated by temperature matched darks. When the object is bright nice results can be achieved.
For dim objects a cooled camera is better suited. When you combine the data with OSC you can clip the background of
Ha to get rid of the noise and banding. For monochrome pure Ha image apply a lot of noise reduction to the dark parts of the image.
Process OSC without deconvolution, apply plenty of noise reduction and preserve color while stretching. Apply devonvolution on L, stretch and combine it with the OSC data as you would in an LRGB workflow.
This data can be processed as purenarrow band in HOO. The OSC data can be used to add natural color stars to the image. The processed HOO+OSC version is shown as the main image in the gallery. The HOO version is linked in the description below the image. It is not recommended to process the OSC data without narrowband as the OSC camera is not modified and so does not pick up enough Ha data for this object.
Recommended for beginners! Processing monochrome images is very easy. As there is no color you cannot get it wrong. Ha data is usually processed to a black and white image. To give it a vintage look it can be converted into an RGB image and colored in an orange brownish sepia tone as shown in the gallery.
All the above OSC data have been calibrated by bias and flats. The Ha data have been calibrated by bias, darks, and flats.
The stack can be processed as it is. The only reason for posting them here is that you might wish to compare your own calibration
frames to mine because you are not sure what they supposed to look like. You might also have a look at the files when you find
problems in my data and want to track down the reason.
The bias frames have been converted to super bias files in PixInsight. Both, the original file and the super bias is provided.
While bias and darks are only related to the camera flats are taken every night. The flats files are just typical example files.