Thanks for the comments.
There are some caveats to UV imaging. The extinction factor is large.
I tried using the filter as a pseudo Calcium K line filter on the Sun and found I needed to increase the exposure time by about 4-5X when shooting at 45 degrees above the horizon as compared to imaging near the zenith.
I suppose this is not that surprising given it is very difficult to get a Sun tan in the morning or late afternoon.
Pollutants such as smoke haze make UV imaging very difficult.
Once again this is not surprising as UV block filters cut through haze, UV pass filters on the other hand have quite the opposite effect.
Quote:
Originally Posted by alpal
Hi Stephen,
Wow - that's got a nice low noise smoothness to it.
Could we see a 1920×1080 version of all of them please?
cheers
Allan
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Allan,
The direct links are to images at 80% of full resolution. The colour data was taken nearly two years old and due to the image rotation using a helical focuser much of the combined image has been cropped out.
Regards
Steven