Last year I started experimenting with a SkyWatcher StarAdventurer and a 135mm lens as a quick setup, highly portable, wide field imaging rig. What I soon discovered was that getting an accurate polar alignment was hard, and I missed the accuracy of guiding even in the resulting wide field images. This led to further purchases and a new experiment. The two big questions I wanted to figure out were: is it possible to mount my DSLR plus lens to my existing AVX mount, and is it also possible to incorporate a guidescope and camera into the rig. The result is the following setup:
- Celestron AVX mount and tripod
- The ball head adapter from the Star Adventurer kit
- An Artcise ball head
- Canon SL2 (modified)
- L-eNhance clip in filter
- Rokinon 135mm
- Hot Shoe mount
- Svbony mini guide scope
- SSAG
This rig does have some drawbacks. The camera attaches to the ball head using a standard camera screw, meaning one point of attachment, so that flexure is possible. The guide scope attaches to the camera via the hot shoe mount, meaning one point of attachment, so that flexure is possible here as well. The resulting payload is so light that it remains a bit off balance even with the counter weight as high as possible.
Nonetheless - and with some of the forgiveness of ultra wide field imaging - this rig produced a decent image.
It's worth noting that seeing was relatively poor due to the amount of moisture in the air, but I haven't been able to image in quite a while so I couldn't resist the mostly clear skies.
The software for this image involves the following:
The post processing was fairly simple: DynCrop, ABE, SFT/HT. Use StarNet to produce a starless copy. Do a masked stretch on everything to reduce some of the background noise. Combine the starry and starless frames using NBRGBCombination.
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As of revision 1, the image now contains the following light frames (with associated calibration frames):
- 115 x 120 seconds @ iso 1600
- 30 x 300 seconds @ iso 400
All frames were taken at f/2.8
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For revision 2, I read somewhere on CloudyNights about someone not using bias frames for Canon DSLRs. Does anyone else have an opinion about this? Anyhow, I reprocessed from the start using only light, dark, flat, and dark flat frames. This also gave me another opportunity to work on processing.
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