Having read an article recently about using a creative web cam to capture images through a scope I thought I might try this using an old one I had knocking around as a "nothing lost" type of exercise. However, I beleive that I may be overlooking something obvious as it didnt appear to be quite the simple exercise I thought it would be and could do with some advice please.
I used a Creative webcam 3 (old model) and fashioned a tube using a 35mm film container which snugly holds the web can focus ring. This is secured to the scope using the modified dust cap. All in all an adequate exercise so far.
My concern is that focussing of the web cam is going to be a problem. While i dont imagine it to be impossible, it is fairly painful to remove the cam, twist the focus ring a little (and this cam has a very large focussing range) replace check, remove, etc etc etc.
I have heard that the reason why the toucam is used is because it has a removable lens. Hmmmm, am i missing something here? I hear about this CCD lark and am wondering if this refers to a particular improvement to the newer cams which make planetary imaging possible without a lens on the actual webcam. Would this be right?
Can anyone offer any advice to help me get this set up working please? Of course, if you think I'm flogging a dead horse just let me know and I'll try to convince the wife that I need to spend even more money! Take a look at the pics for clarity.
If there is then your setup will be fine. It is called afocal photography. I find as a rough rule of thumb, focus on you finger or hand at say 1 to 2" away and then insert into the telescope so that the camera looks at the image on the eyepiece. You should be able to focus with the telescope focusser.
The other way is to remove the lens of the camera and then attach the camera to the telescope but without the eyepiece. This is called prime focus. You use the telescope focusser to focus. With a toucam you get high magnifications ie 208x in my 10" reflector
No there isnt, and i am begining to see the flaw in my plan and the reason why the idea didnt work so well. In essence I need to focus the image directly onto the chip in the webcam which allows me to use the telescopes focus. This is preferable as I can use the eyepiece also without having to remove any of the camera stuff. However,I may try the afocal method prior to removing the lens from this webcam as I think that this might be an irreversible operation on this model. But also...
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The other way is to remove the lens of the camera and then attach the camera to the telescope but without the eyepiece. This is called prime focus. You use the telescope focusser to focus. With a toucam you get high magnifications ie 208x in my 10" reflector
According to the article you referred to, it sounds like the magnification using afocus will be much greater than prime focus? I guess that the magnification level does not go beyond the useful magnification of the scope because afocal has the effect of increasing the focal length rather than trying to increase the eyepiece power alone? According to the article, with my tube length (between camera and ep) of 56mm and using a 10mm eyepiece I would be increasing my focal length to 56/10 X 1325mm or 7420mm Is that how it works? sound a lot.
I'll keep you posted. I'm feeling pretty excited at the thought of eventually producing some of the images I see on this site.
By the way, i enjoyed reading your viewing report in another thread. I can see that as my experience grows, I will develop many more objectives for my viewing than what is immediately obvious when you first take up astronomy.
Are you going to the viewing night at Kulnurra on the 1st Jan? Do you kno0w of any really good out of the way spots near us which are worth going to for darker sky viewing? You are in Cabramatta right?
I'm still green to all this too, but apparently if it has the CMOS sensor rather than the CCD sensor, word has it that they don't perform too well as an astrophotography camera. (all to do with light sensitivity)
But I would'nt be letting that stop you from trying. You have nothing to lose by trying it out.
Hope I didnt appear to know what I was talking about, as it happens I think I have misuderstood the article you posted but this is where I was quoting from. please see this below.
magnification of Telescope = objective Focal Length ÷ eyepiece focal length
Example: 600mm focal length telescope (TV-85 telescope) with 10mm eyepiece = 600/10 = 60x. If camera uses 50mm lens, above equation yields 3000mm focal length.
So my 1325mm Focal Length /10mm ep =132X Magnification. I then would multiply this magnification by the camera lens focal length to obtain my effective focal length according to this passage. So if the camera had a 50mm FL my effective FL would be 50 X 132=6600mm
I can see how this might be the case as when taking afocal shots using a digital camera on optical zoom through an eyepiece I can achieve huge magnifications as I am altering the focal length of the camera lens.
I think where i may be going wrong in my comment earlier, is that i am not in fact altering the FL of the camera by simply placing the lens at the end of a 35mm film tube. This is merely a function of focussing on the ep glass from a distance. Perhaps because the prime focus method uses no ep then the value for the non existent ep moves to or close to zero and then Magnification is Telescope FL/zero (or someting close to ) which gives high magnification? Also the FL of these small webcams is likely very small and so have a minimal effect on Telescope FL.
If someone could confirm this to be correct, I will know I'm picking things up ok.
I'm still green to all this too, but apparently if it has the CMOS sensor rather than the CCD sensor, word has it that they don't perform too well as an astrophotography camera. (all to do with light sensitivity)
Thanks, looked at the links and they confirm that this camera is a cmos one. I suppose that it may still have some abilities as a planetary imager which is what i plan to spend some time on as deep space requires long exposure times etc etc and the tracking on my scope doesnt appear to be the best.
I'll give it a go at venus, moon, mars and saturn and see how it goes. I managed to gain quite a bright image in the preview of mars last night just not in focus. I will endeavour to remedy the focus part having learned from this thread and let you know how i get on. If it works I have some collimation to do also before posting my first pic!
theres a sports field about 20 mins from my place at the oaks
If you are planning a visit there and don't mind company (and educating a newbie), I could drive over with the scope some time maybe over the holidays?
I have a better idea, when my astro soc has a viewing night I'll tell ya. its just down the road from the said field at an airstrip. and has less lights
I generally only observe from my backyard unless i go to an observing night with mike n' the gang at kul-whatsit or oaks with MAS
Muddy, I got to say I think your flogging a dead horse.
It is likely that this chip is not advanced enough in two ways. First, I would think that the frame rate will be only around 2-5 frames a second. Second, it is likely that you will loose many frames as it goes down the pipe. Possibly not USB compatible.
Also, I would think that the chip size and pixels will be totally inferior. I suggest that for 140 dollars the toucam is a good starting point. LPI is also not expensive and the Neximage just a little more.
Don't waste your time. This aspect of the hobby is frustrating enough, I would not bother getting anymore frustrated.
I do intend buying a decent astrophot set up eventually. I guess that its the wrong time of year to be buying yourself presents and I cant wait to see if santa bought me a neximage! (Gee, i left enough print outs from the web lieing around in the study for someone to find). The cloudy night has stopped my experiment tonight so I could only take what I've learned from the replies to this post and make up an experiment in the yard with some leds in the ground across the garden. Guess what FOCUS ACHIEVED. This might not prove that the set up will be any good as you predict but at least I've learned something from messing around.
Who sells the Toucam here or is it mail order only? I've read the posts in other threads and am undecided between the toucam or the neximage, they sound like the same thing from what i read apart from price.
Ving.. Great Idea, I need to start mingling with a few people who know what theyre doing. Only way to learn! Look forward to it.
You can get the ToUcam from telescopes-astronomy.com.au for about $220, by the time you get the threaded 1.25" adapter and IR blocking filter. The NexImage is a little more expensive, but it's all in one package.
