Orion


I took some baby steps into astrophotography over the summer with the milky way image. This time I take a larger step forward. The camera is riding on a Losmandy GM811G mount and tracking the stars. The ultimate goal is to have the camera attached to a small telescope but for now it is the camera and a 70-200mm F/2.8 zoom. The camera was at ISO 800 and the lens was at 70mm. The target was the constellation Orion.

I selected Orion because it has a number of interesting deep sky objects within its borders and it will also be gone from the night sky soon. This was likely to be my last chance to photograph it until the fall.

The physical setup for this kind of astrophotography is quite a bit more complicated than the earlier effort and it didn’t all go smoothly. The software I was using to control the image capture, Sequence Generator Pro, failed to do plate solving properly so it left the camera pointing a bit off from where it should have been. However, the whole of Orion was still within the frame so I didn’t try to fix it.

The camera captured 15 two minute exposures and then plan was to then spend some time imaging the Pleiades and then capture dark frames. However, the temperature was just below freezing and the camera batteries were drained while I was trying to get set up for the Pleiades. I had to capture dark frames a couple of nights later and it wasn’t quite as cold that night so not an ideal situation. I also was not able to get flat frames for this session but I did use 25 bias frames.

I ended up processing this image twice. The first time I used Starry Landscape Stacker to stack the images and produce a TIFF that I further processed in photoshop. I had such a difficult time managing the background gradients in photoshop that I opted to heavily crop the image concentrating on the belt and sword region of Orion.

For the second attempt I used PixInsight and was able to do a better job with the gradients and so use the entire image. However, there is an artifact in the image that runs from the left between the Saiph and Rigel. While Barnard’s Loop is in this region, I would have needed a lot more integration time to capture this very faint cloud. Instead, I think this is some sort of reflection issue. Sirius is not to far from Orion and perhaps some of its light made it into the lens or it might have been condensation on the lens though I was using a dew heater. Whatever the source, I couldn’t remove it.

Although a few things went wrong, there were some happy surprises. I expected to see M42 and M43 but I didn’t expect to see the Flame and Horsehead Nebulae. The horsehead, in particular, is a bit of a challenge for a DSLR camera since they aren’t particularly sensitive to that deep red color. It’s faint but it is clearly visible. The stars were round indicating that the tracking was good enough to not need a guide scope and camera. While I expected this to be true at 70mm, it was nice to see one assumption confirmed.

The next effort will be to try the Pleiades with full batteries and hopefully by then the 12V power adapter for the camera that I ordered will have arrived. That should allow me to image for several hours off the same battery that is powering the mount, computer and dew heater. I’ll also raise the focal length to 200mm. Here’s hoping another clear night comes soon!

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