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Another from the webcam + 135mm camera lens


Kaptain Klevtsov
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I think that's a great set up you have there CC as shown by this image. The SC3 chip has nice small pixels and works really well at short F/Ls. You ought to try it on some big targets. Your try on M31 looked promising. How many subs and what exposure?

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M31 - 66 subs at 30 seconds

M13 - 39 subs at 10 seconds

These were both done in very poor conditions with lots of high cloud so I'm hoping for much better results as time goes by. I've also got 60mm and 500mm lenses to play with.

Watch this space, contrary to what the Met. office say, it looks like it might be clear here tomorrow, and I don't have to get up early as I'm taking the boy to the hospital therefore no work.

Also I've got the filter to work. I remebered as i was typing the above that I'd sawn off the end of a camera nosepiece to allow the focal reducer to work. Well I found the offcut and it works. Which filter will give me the better go at M31 - CLS or Ha? (Or the Antares ALP could go in there but I've not had good results with it using the DSLR.

Captain Chaos

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Which filter will give me the better go at M31 - CLS or Ha? (Or the Antares ALP could go in there but I've not had good results with it using the DSLR.

Since most of the light from M31 isn't in the Ha spectrum a CLS filter is a much better choice. You can use Ha on galaxies as part of an RGB image to bring out the Ha regions but for a monochrome you would just end up having to use longer exposures for no real gain. Best reserved for emission nebulae. Your set up with an Ha filter would be great for something like the Pelican or N American Neb

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Excellent CC. How do you focus?

Er, turn the turny bit on the lens.

Set up the webcam with exposure such that its not all black, turn it a bit, wait for a frame, turn a bit again, repeat until something shows up then iteratively go back and forth until its good. Start with the gain high to show up the bright patches more and turn down the gain to get even closer. faint stars will show up at focus which aren't there even slightly out of focus.

Its easier than it sounds.

Captain Chaos

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For meteors I'd probably go wider, 35mm lens perhaps. From the ones I've seen (going back a year or two) during the showers, they tend to get all over the sky a bit. recently viewed meteors cover about half the sky, so thats VERY wide angle. Must look up when the next gig is for the meteors. I think it would make a great shot if I could centre on the radiant, track on an EQ mount and shoot for a couple of hours.

Hmmmm.

Long exposure mode with the lens stopped down to get , lets say 2 frames a minute. A couple of hours should be doable I think. I now need to look for some images on t'internet which show the spread from the radiant to get an idea of how wide angle I need to go with this. Does sound a cracking idea I must say.

Anybody any idea how bright they are (to work out if they would show up with the lens stopped down)?

Anybody tried a SC1 webcam with the normal webcam lens on for this?

Just scored a 740 Toucam off e-bay so maybe it's got a new job next shower.

The list of stuff to do just grows and grows as do the clouds (cloudy again here tonight after mini-tornadoes, raining cats and dogs and a clear evening).

Captain Chaos

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