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Post by doitalldave on Aug 15, 2008 11:01:20 GMT
Hi every body can any one point me in the right direction to help me with getting my webcam to focus properly. The set up I’ve got is • Telescope Astro 2000 (114/900) • Eye piece Plossy 4mm & 25mm • Webcam SPC 900NC • Standard telescope webcam adapters The problem in the focusing I’m getting is that when I adjust the focuser I can go from a blurred image to an almost focused image through to a blurred image again. The sharpest image I’m able to achieve is for a better phrase need’s glasses, has this problem got any thing to do with the between the CCD and the eye piece. I have tried the K3CCD Tool to help with this issue but to no avail. If any one out there can help with this or point me in the right direction it would be gratefully appreciated.
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Post by irishbloke on Aug 15, 2008 11:57:56 GMT
Hi I had the same problem when I started using the same web cam. I use a skywatcher 130PM telescope and have found the focus point for the web cam would be inside the focusing tube. I either have to use a barlow which extends the focusing point further out and doubles magnification or try to use an eyepiece in projection.
I think a focal reducer also extends the focus point out and decreases magnification allowing you to see more. That's an option I haven't got to yet.
It took me a long time to work out how to do it. It stops you actually looking at stuff while you figure it out. But the barlow will work and hopefully it will get you going.
Best of luck. Brian
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Post by doitalldave on Aug 15, 2008 15:34:08 GMT
Thanks for that I’ll try a Barlow lens tonight if the weather allows lol. Also I’ve been doing some research into the matter and most seem to think a focal rectifier is the way to go, but I don’t want to spend 30 quid on something that is not going to work if you know what I mean. Will try your suggestion and let you know.
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Post by phoenix on Aug 15, 2008 22:12:28 GMT
This sounds like you can get focus without any additional aids. You have to remember that you are using a webcam which has a fairly low resolution and that even when you reach optimal focus the image will still not look very sharp. Its worse at the minute given that any clear spells we have had have been very poor for imaging.
Even the best planetary images taken with web cams have raw frames that look out of focus and its only by stacking multiple images that you can sharpen up the results.
I use the same webcam and focus is always difficult. The moon is the best starting point and then move on to planets. Go for what you think is best focus, do an avi of about 500 frames and then stack them to see what you get.
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Post by doitalldave on Aug 16, 2008 9:47:41 GMT
Thanks for your reply but! Not sure about it being just the equipment I’m using, have tried it in day light, and focusing on an object about two miles away is still in possible to bring it in to anything like focused. Will keep persevering sure I’ll be able to sort it out eventually
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Post by irishbloke on Aug 16, 2008 17:03:15 GMT
Thats the thing your focusing on much further away than 2 miles. If you want a test during daylight see how close you are when you can focus on and object and you'll probably find you're right down to the bottom of your focuser. That shows you its a focal distance issue. It's not saying there's anything wrong with your equipment just that its made for focus much further away and that the ccd chip is different from your eye. I found the playing during daylight has helped me get my technique right for the dark. Also it's helpful to use a Hartman Mask. You make it yourself. Here's a link for a pdf template genterator for a hartman mask that will fit your scope. billyard.servehttp.com/Hartmann.htmlJust measure the diameter of your tube, enter it and the size of your mirror and the number of holes you want and hit generate. I like 3 holes as you can tell which way the image is out of focus and correct it. When you put the mask over the top of your tube you will see the 1 object you are looking at as 3. You just keep focusing until there is one image. With 3 holes 1 image will move from one side to the other as you over or under focus. Just search for hartman mask on internet and you'll find out more about it.
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Post by nemesis on Aug 16, 2008 17:21:34 GMT
Brian, to be truthful two miles...or even 100 yards away....is infinity in photographic terms, as far as depth of field and focus is concerned, so there should be focus possible.
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Post by doitalldave on Aug 18, 2008 8:38:37 GMT
i know that focus should be possible but it isn't. form the research I've done and the experimentation i still can't achieve focus could this have something to do with the distance between CCD and the eye piece lens, and if so would a focus reducer solve the problem
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Post by Phil on Aug 18, 2008 12:49:29 GMT
something to do with the distance between CCD and the eye piece lens Quick note: you do know that the webcam replaces the eyepiece in the holder?
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Post by irishbloke on Aug 19, 2008 19:09:58 GMT
I may not be using right terms but the barlow or focal reducer will work. It seems to me that my focuser doesn't allow me to get the ccd close enough to get focus.
I have found I can focus on near things during daylight but can't get focus on say the moon at night without the barlow.
Its definitely worth cracking it as watching the moon fly passed on the full size screen is cool. Hope you crack it.
There's a couple of others at the meetings that do webcams as I spoke to a father and son who do it at the last meeting. Can't remember their names as I'm wick with names. You might catch them next meeting!
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Post by nemesis on Aug 19, 2008 20:43:43 GMT
Which meeting is at Ballyclare High, Monday September 1st. All welcome, even Stevie.
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Post by markdj on Aug 22, 2008 22:01:46 GMT
Try setting your webcam during the day and look for the Sun, but take the obvious precautions with looking at the Sun.
Don't laugh for me saying to look for the Sun - from Thursday we are in for some very good weather and we've had good sunny spells this week, there is hope yet for the Summer.
Use a solar filter over the front of the scope and try using projection with your finderscope.
With your webcam, it is best to remove the lens and take out the eyepiece and use it in "prime focus" mode. If you can't focus then lift the webcam back from the scope holding it in line to see if it is a back focus issue - you may need an extension tube.
Eyepiece projection is the other method which sounds like what you are using. I have never been successful with eyepiece projection but I might try it as I have a Logitech with an autofocus lens which is irremovable without destrying camera.
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Post by nemesis on Aug 22, 2008 23:47:35 GMT
Thanks for that, Mark...I also have a Logitech, and i was examining it just last night and wondering if it could be used for just that purpose.
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Post by doitalldave on Aug 24, 2008 16:18:01 GMT
Right I’ve just got a quality Barlow x2 lens and this has improved the image quality 4 fold. It still not perfect but I’m pretty sure with some playing about it will be possible to archive a good image. Thanks for every ones help it has been most useful. ;D
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