I'd made one attempt at this planet some years back, but with it being so much fainter than the others, I couldn't get a bright enough image onto my webcam's sensor. However now that I've modified the camera for long exposures, I could have another go.
The main difficulty in imaging planets at high magnification is the seeing - the turbulence in our atmosphere. And with Uranus being relatively low in the sky (only 27 degrees above the horizon at 9pm), I'd be looking through quite a thick column of air. The usual technique is to take very short exposures (less than 1/30-sec) to try to "freeze" the brief moments of good seeing, but with exposures of >1-sec I couldn't do this. Nonetheless, I captured a few sequences of 300 images (as .AVI files) over 1.5 hours - the results got steadily better as the air in my telescope tube settled and the planet got higher in the sky - but then it started to cloud over.
All I'd managed to capture was a fuzzy blue disk, so I decided to try the planetary registration functions in IRIS for a change (rather than RegiStax). It was soon apparent that the Blue channel was suffering more dispersion than the red or Green, so this was all I managed to salvage:
- Stack of 100 (best of 300) 1.1-sec images from my LX webcam, processed in IRIS
- Uranus 14_10_2013.jpg (3.25 KiB) Viewed 2990 times
