Following success in imaging the discs of Jupiter's satellites, last night I decided to have a go at something a bit harder: Uranus's disk is bigger but much fainter, and seeing is a real problem as exposures over 0.5 sec are required. Success but I'm not thrilled with the result - the seeing was not very steady.
Then I really got headstruck - what would happen if I turned the exposure right up? Removed barlow, set exposure to 32 sec ... ran into problems with the driver which thought the camera was not responding; however I did manage to get a "snapshot". This is not to scale with the above, I've reduced it in size quite a bit to try to deal with the seeing & tracking errors - also I've had to process out the hot pixels.
2009 Sep 14, approx. 0040 UT. From the top: smudged image of Oberon; Uranus, hugely overexposed; Umbriel, smudged and faint but clearly visible; smudged image of Titania. The smudge near the upper left corner is a mag. 16 (approx) field star.
Who would have thought that you could image mag. 15 objects with a webcam? Clearly it's not the best tool for the job (that's amp glow in the upper left) but it does it.
Edit: Here's a better way to image faint objects:
Hand held shot of video monitor screen, Watec 120N, 0.5x focal reducer, CPC1100.
Titania & Oberon were clearly visible at the eyepiece but I couldn't see Umbriel with my CPC1100 despite good transparent sky.
That's an excelent piece of work with the "webcam" Brian - the DMK is a bit more than just a webcam but impressive nonetheless. But even more impressive is the Watec - that's a video camera! Quite extraordinary!
But even more impressive is the Watec - that's a video camera! Quite extraordinary!
Yeah, very sensitive but quite crude ... I find it handy for checking on dwarf novae etc. which are below the visual threshold of my scope, it's easy to get into the 16s even with a full moon around. But actually making an estimate is a different matter.
I'm surprised these video cams aren't more popular with casual observers - expense I suppose, but they act as an "aperture multiplier" for deep space objects (at least 2x) & deskill the detection of faint objects, in fact you don't even need to get dark adapted. They're quite good at pulling coarse detail out of planets too. Great for public viewing events!