Webcam Dobsonion

[Magic]

Hey Guys,

I currently take all of my pictures by holding my phone up to my dobsonion's eyepiece. With a bit of practice i can capture Planets but not any of the DSO's.

Is it possible to buy a nose piece to go on the eyepiece as shown here: 'http://www.ebay.co.uk/sch/Telescopes-Binoculars-/28179/i.html?_nkw=webcam+nosepiece' ......and then attach a webcam to it?

I'm not sure how this is possible really. Does the webcam just fit on to the nosepiece?

Thanks!

Magic.

[JamesF]

Some webcams can pretty much just have the lens unscrewed, a nosepiece screwed in to replace it and be put into the focuser with no other modifications required. Others are a fair bit more complex and others are for all realistic purposes not worth trying to modify.

If you want something that's cheap and relatively easy to start with, the Xbox Live camera is pretty simple to modify. It's not the best camera, but it does the job.

No webcam is really going to capture images of DSOs without serious modification though. As a general rule they just don't allow the length of exposure that you need for DSO imaging, and using a dob for DSO imaging is going to be somewhere on the scale of pretty difficult to near impossible.

James

[umadog]

You can't stack many short exposures to achieve good DSO images. You need long exposures. This is due to the noise inherent in reading data off a CCD chip. Google "Read noise CCD" That's why you need a driven EQ mount and a camera taking of taking long exposures. Preferably a cooled camera.

[Magic]

Thanks a lot for the responses guys. I was thinking about a Xbox camera and that is true but I am not going to be doing Exposures or anything like that. I'm just talking about photo imaging how it is actually being shown through the scope. Would that be possible? Filming or Taking a photo to show what i was actually seeing through the eyepiece?

Thanks,

Magic.

[JamesF]

Well, it's kind of possible, and kind of not

The underlying issue is that cameras don't work the same way your eye and brain do, so you're never going to get "exactly what you see". Using a webcam and stacking the images for planetary imaging is probably as close as you get and I'd always encourage you to get yourself an Xbox cam and give it a go. Where DSOs are concerned though, stock webams just aren't sensitive enough over a short enough period of time to emulate the eye and brain, and when you start taking longer exposures, they can do things the eye and brain can't, so you never really end up with "what you see"

James

[umadog]

It's basically not possible unless the scope tracks because you will need to take exposures which are a few seconds long in order to see anything at all with DSOs. With planets you need to take a movie at high frame rate then process it. At the scope you won't see much with a normal webcam. However, there's a specialised video camera for the task. It's called a Malincam and it's not cheap.

[Magic]

Thank you to both of you for that It is a real shame I will have troubles picking up DSO's however i will try the Xbox camera just because it would be a lot easier than holding my phone up to the eyepiece. Funny really how the webcams cannot pick up what are eye's can! I've looked up a Mallincam, there doesnt seem to be too much information at the moment guessing by how new they are, but it looks as if they build the image up through the eyepiece? I dont know it is very confusing.

Thanks for the great posts guys,

Magic.

[umadog]

Malincam are basically just very fancy webcams. They're low noise, sensitive, and have a lot of integration options. They can be B&W or colour. The image is built up over short periods of time e.g. 5 to 15 seconds. This lets you point the scope at stuff and see something more or less live. It's a little like low-resolution astrophotography. Works pretty well. I saw it in action once: Malincam on an 18" Obsession in very light polluted skies (about Bortle 7) and we saw the Horsehead. Only time I've ever seen it.