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Old 31-10-2013, 08:46 PM
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CCD Inspector and collimation

Has anyone used CCD Inspector to collimate their scope? I tried it last night - used the live mode, defocused star routine.... went from reasonable collimation to a dogs breakfast quite efficiently. Ended up going back to the laser....
Seems like such a good tool, but I could not for the life of me make it work for me last night....
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Old 31-10-2013, 09:54 PM
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Only ever used it AFTER colimating to check. I don't think I'd chase the tail live
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Old 01-11-2013, 01:24 AM
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You'd want seeing to be better than excellent else it will jump all over the place. I guess if you use it a lot then you'll know how it'll react and know how to use it. I only ever used it to check collimation not set it.
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Old 01-11-2013, 06:57 AM
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multiweb (Marc)
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I use it all the time. It takes a little getting used to refine your collimation. The laser will get you close but the start test is the ultimate test and will tell you a lot more. Your scope needs to be in temperature. You need reasonable seeing and pick a star close to the zenith. Also you can do it on a bench on an artificial star which I use all the time indoors or outdoors.

Here's the kind of patterns you can expect.


Last edited by multiweb; 01-11-2013 at 07:11 AM.
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Old 03-11-2013, 08:00 PM
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You can use CCD Inspector to verify collimation. But it’s only another tool. These are my observations only – nothing more.

First thing, get a reliable laser collimator. The Howie Glatter has worked best for me. I have had others, and in the end, they are no longer used, and I bought the Howie Glatter. The Hotech is consistently inconsistent. It would always show a different location every time I used it. And before you say it – Yes, I looked at every video on the web. Rotate it and it would draw circles. OK in V-Blocks, but those rubber O-Rings…. Enough of that… I might get yelled at

First: With your good laser collimator, collimate your scope as per known methods for your scope.

Second: Now it’s time to use your eyes. Stick your CCD software into focus mode if you have it. Then rack it out of focus a bit, and compare the stars in the corners with one another. I’d work off these first, get them all looking right. I know it is tempting to use the old defocused star in the center, but looking in the corners you can adjust it pretty close. Once you are satisfied that you are very close, it is time to dig out CCD Inspector

Third: Fire up CCD Inspector. You really have to have a good night of seeing to use CCD Inspector, turbulent air is not your friend. Take an image with a lot of stars evenly placed in its field. It does work better with an even field. Look at your results, and RECORD EVERYTHING. Write it down – don’t rely on your memory. Mine is broken I’m sure, but I can’t remember. After several iterations, things will get funky. Now tweak it if you have to – only a bit. Take another image, and note which way it has gone. Only one adjustment at a time, otherwise you can’t be sure which adjustment worked.

I have tried real time collimation, but you would have to have very good seeing for that to work. If you want to try that, I would average min the last three measurements, record, and then adjust. Here are the results for a Vixen R200SS. I am using a Televuee Paracorr Type 2, spider milled to a thickness of 1.7 mm vs the original 6.0 mm spider. This was collimated with the Howie Glatter laser, the tested with CCD Inspector to verify collimation on a 8 / 10 seeing night.

A high quality laser will give you a good starting position with a newt. You can also use a good laser on a Cass to get you into a good starting position for final tweaking as well. Wait till you have that terrific still moon light night for collimation. Don't rush it... and don't rely on that memory - make notes.

Terry
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Old 03-11-2013, 08:10 PM
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SImilar to Terry (I think he coached me during one of our LONG phone calls ), I fine tuned my DED108SS refractor (using the tools and techniques suggested for a TV Petzval-Nagler on CN). It's still just a gnat off, but this was the worst of the 5 images I used.
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Old 03-11-2013, 08:58 PM
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Thanks for the detailed info Terry...
I do have a Glatter Laser and the tublug, always seems to get me pretty close.
I'll give your iterative procedure a go soon. How far out of focus do you make it - so you see donuts?
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Old 04-11-2013, 02:44 PM
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Hey Lee,

Just till you see donuts. Not to far out. Make notes, one adjustment at a time, and take your time. That tublug will get you pretty close. I made the mistake of centre marking my mirror with a very small circle - It's right in the middle of the tublug and can't be seen. A bit larger, and it is easily seen on the tublug.

Terry
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Old 04-11-2013, 10:59 PM
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Thanks for the positive comments on my gear, guys.

" I made the mistake of centre marking my mirror with a very small circle - It's right in the middle of the tublug and can't be seen. A bit larger, and it is easily seen on the tublug."

For that reason, people have asked me to make the hole in the center of the screen smaller, but that would reduce the outgoing light flux, and thereby decrease the contrast of the shadow.
It would be possible to make an "aperture stop" of paper or tape with a smaller hole in the center, if it can be accurately centered on the tuBlug aperture.
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