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Old 22-07-2008, 09:20 AM
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cookie8 (Vincent)
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900nc lunar capture : help

Just received my 900nc & adapter yesterday. Downloaded K3CCD-1 & Registax. I have never used a TouCam before thought the moon's craters a good place to start. I could not focus with a 2x barlow with my 12"LB which has a FL of 1500mm( may be I did not try hard enough) so tried without one. Still the moon drifted very fast across the FOV. I have no idea what settings to use. Need plenty of your help guys to get me started.
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Old 23-07-2008, 03:54 PM
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Merlin66 (Ken)
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Cookie8,
You raise two issues:
-getting the webcam to focus
-drift of the moon across the field

If you can see an image of some craters on the screen, then at least you're getting close, more practise and patience....

The second issue is a result of using a scope without a RA drive. Bear in mind the webcam's field of view is the "equivalent" of using a 6mm eyepiece
so things will appear to move pretty quickly.
Again, some practise! position the object at the edge of the field and record as it drifts across.... K3CCD can still stack the centre parts to give a good result.
To improve focussing, set the scope up during the day at a distant object and move the webcam, focusser until you get the best results. I mark my focusser tube position with a pencil line as an aid to find a close staring point later.
Keep practising.
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Old 23-07-2008, 07:14 PM
helioz (Erwin)
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Cookie8,
I have just started using my 900NC and my problems were similar to yours.
When using the camera you will find that it's only a very small range of the focuser where you can make out anything at all, the rest of the range is just a blurr. As you are moving the focuser it's easy to move through the "in focus" point without realizing it due to the screen update time.
Select 25fps before you start.
Setup during daytime is a lot easier.
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Old 23-07-2008, 07:21 PM
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cookie8 (Vincent)
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Thanks Merlin for your advise & encouragement. I think the reason that I couldn't focus in the first place was I did not give the mirror enough time to cool down.(I was in a hurry to test my new toy) The whole image "boils" unsteady so hard to focus. I am considering a round table platform for tracking. Is it really worth it? Almost everyone uses a 5x Powermate. Can I use two 2x barlows? Does it give me 4X ? And IR filter in front of webcam is it neccessary? Sorry for all these questions.
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Old 23-07-2008, 07:25 PM
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sheeny (Al)
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Get a Parfocal EP

Just another little tip that may help.

Have a play during daylight, and get a focussed image in the webcam. Then try different eyepieces and see which one is the closest to being in focus without adjusting the focusser. If you can find one that is close enough or that comes into focus without winding the focusser out too much, you can use it as a parfocal eyepiece. i.e. parfocal means the EP and the webcam will be in focus at the same position.

Having a parfocal EP will greatly assist you to make the most of your webcam - especially if you aren't tracking the moon. You can use the EP to get the focus right (or at least close if it isn't truly parfocal). You can buy a parfocal ring to clamp around your EP or webcam nosepiece so it slides into the focusser just enough to match the focus of the webcam/EP.

I'm pretty lucky... my 10mm guiding EP is parfocal with my ToUcam.

Al.
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Old 23-07-2008, 07:27 PM
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Quote:
Originally Posted by helioz View Post
Cookie8,
I have just started using my 900NC and my problems were similar to yours.
When using the camera you will find that it's only a very small range of the focuser where you can make out anything at all, the rest of the range is just a blurr. As you are moving the focuser it's easy to move through the "in focus" point without realizing it due to the screen update time.
Select 25fps before you start.
Setup during daytime is a lot easier.
Thanks Erwin
Of course ,the update time. I have to make sure it's set to a higher frame rate next time and better preparation during the day.Valuable tips.
BTW can you answer any of the questions in my last post?
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Old 23-07-2008, 07:37 PM
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sheeny (Al)
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Quote:
Originally Posted by cookie8 View Post
Thanks Merlin for your advise & encouragement. I think the reason that I couldn't focus in the first place was I did not give the mirror enough time to cool down.(I was in a hurry to test my new toy) The whole image "boils" unsteady so hard to focus. I am considering a round table platform for tracking. Is it really worth it? Almost everyone uses a 5x Powermate. Can I use two 2x barlows? Does it give me 4X ? And IR filter in front of webcam is it neccessary? Sorry for all these questions.
Cooling time will help you achieve focus (it is hard to focus a blurry image!)

An EQ platform will definitely make life easier for you when using the webcam. Mike used one for ages and had great success.

A 5x Powermate is a great investment, but get the EQ platform first. If you think the moon moves fast past the webcam now, it'll be 5x as fast through the Powermate without the EQ platform.

2 2x barlows would probably give you around 4x but you are adding a lot of glass piggy backing the barlows, so there'll be more light loss, and achievein a sharp image will be more difficult.

A UV/IR filter will definitely help the quality and sharpness of your images. If you keep your webcam and nosepiece always assembled, it will also help keep dust off the sensor. It's not critical when you're starting out, but as you get better at imaging you'll appreciate the difference it can make.

Al.
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Old 23-07-2008, 07:59 PM
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Quote:
Originally Posted by sheeny View Post
Cooling time will help you achieve focus (it is hard to focus a blurry image!)

An EQ platform will definitely make life easier for you when using the webcam. Mike used one for ages and had great success.

2 2x barlows would probably give you around 4x but you are adding a lot of glass piggy backing the barlows, so there'll be more light loss, and achievein a sharp image will be more difficult.

Al.
Thanks heaps Al for your hints. I am certainly looking forward to give it a go again. I will take the scope out in the late afternoon to let it cool down first.
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Old 23-07-2008, 09:15 PM
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Cookie8,
Before you move onto the barlows and/or Powermates, get some practise ( and results!!) with the prime focus. It makes it a lot easier until you develop the skills. Walk before you run.... it'll pay off big time!
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Old 24-07-2008, 04:05 AM
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All the advice above is top notch! Good luck, Vincent!
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Old 25-07-2008, 10:00 PM
helioz (Erwin)
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cookie8,
I think there's a lot to be said for sticking with prime focus as Merlin66 said.
I was of the same mindset as you, thinking that I need magnification.
The fact that the CCD sensor is so small means that you are resolving a very small proportion of the image.
I read somewhere that the small CCD sensor on pime focus gives you the same image as a 6mm eyepiece on the human photon receiver.
I don't know if this is correct, but I find prime focus more than adquate to get started on lunar imaging. Get results with what you got before you buy more gear.

Seeing isn't very good tonight - that's why I'm in front of the computer and not outside with the scope.
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Old 26-07-2008, 09:21 AM
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Thanks Erwin,Mike & Merlin for your advise. I will play around tonight (forecast clear) with the 900nc attached to my 3" 480mm tracking refractor on a cheap eq mount and see what happens with Jupiter. I expect a much smaller image but much easier focusing & longer video loop. Also less affected by seeing & tube current.Right? Has anyone try & what is the result?
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Old 03-08-2008, 11:50 AM
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Hi cookie8
I thought I might add my 2 cents worth as I have only just started imaging with an SPC900NC and I share your pain. All your other advice so far looks pretty good. I would suggest checking out another capture program (freeware). I found wxAstroCapture a lot easier to use, with a better behaved user interface. All the exposure controls etc work like they should and you can still get into the Philips driver dialogs if you want to try digital zooming etc. It also has provision for driving the long exposure mod should you go to this later.
You can download it here:
http://arnholm.org/astro/software/wxAstroCapture/
I would agree that prime focus is a lot easier to get the hang of and gives the best clarity because there are no lenses involved. I've also used EP projection but it took some fiddling (in daylight) to find the focus point, which is different from both visual and prime focus.
I bought an iR filter on ebay which helped a bit with exposure setting etc.
I like the verse in your signature.
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Old 05-08-2008, 07:50 AM
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I've improved my focus options by doing some turning on an old 2" to 1.25" eyepiece adaptor. I bored out the back to fit the fllange of the camera adaptor down inside it (the back of the camera housing is flush against the back of the 2" fitting) and I also reduced the thickness of the flange on the back of the 2" to 1.25" adaptor to allow it to go further into the focusser. Possibly overkill but that gives more range with the focusser.

Bob
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Old 05-08-2008, 04:39 PM
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Thanks Peter & Bob for sharing your tips. I am now waiting for first quarter moon & a EQ platform hopefully have something to post soon.
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Old 09-08-2008, 12:28 PM
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Just taken a couple of avi of the moon with around 800 frames each. How do I select the best frame as reference for Registax alignment? Do I need to go through one by one?A pain. They all looks similar to me. Any shortcut?
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Old 11-08-2008, 07:17 PM
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If no particular frame stands out as been crisper than the rest, then just pick any frame as a reference. You can make a "reference" from a sub-set of 50 frames if you want.
Publish you results... like to see how you went.
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Old 12-08-2008, 09:56 PM
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cookie8 (Vincent)
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Thanks Merlin
Here is my 900nc test shot of the moon attached to WO3" 480mm refracter. I cannot bring it into focus with a 2x barlow therefore it looks small. Can't remember how many frames stacked may be 600? Another shot with my 12"LB plus 2x barlow was posted here:
http://www.iceinspace.com.au/forum/s...ad.php?t=34830
Cheers
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