ISO 200, 15 seconds.
This was not a 'serious' attempt for these reasons:
- I have a Pentax T-ring and the celestron 1.25" drop-in t-adapter, but I can't achieve focus. I CAN achieve focus if I let the t-adapter loosely sit in the draw tube with the extention tubes removed, but because nothing is screwed in, the camera is sitting at an small angle (the focal plane is at a small angle with respect to the sensor plane). I'm going to call Explore Scientific to see what they recommend.
- Very rough polar alignment by pointing appropriate tripod leg approximately north. (It's not possible to polar align from my 2nd floor apartment balcony). Most, but not all of earth's rotation was removed.
- Image taken near soccer field flood lights, in a red zone.
- collimation was not checked but should be close.
1) How do I test for the presence of vignetting? My 1.25" t-adapter looks pretty restrictive, but my sensor is only APS-C sized.
2) Is there any free gradient removal software?
full size: http://www.astrobin.com/26656/