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A CCD inspector thread...

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#1 CounterWeight

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Posted 05 October 2013 - 09:04 PM

Prompted by Madratter thread on his scope setup and test I just wanted to start a named thread on this software. I've never used it but will be before too long I hope? Anyway a place to post experience and usage tips... I am afraid to try it on my current setup!

#2 Madratter

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Posted 05 October 2013 - 09:36 PM

Best reason not to try it now is so you don't waste your 30 day trial.

I can think of 5 main uses for this software:
1) Collimation
2) Eliminated Tilt (with adjustable focusers)
3) Determining best focus to minimize curvature
4) Determining best spacing with reducers to eliminate curvature.
5) Grading images.

For me, I have other software that I use to grade images. A free alternative is Deep Sky Stacker. But what I actually use is the grading within Sequence Generator Pro.

In my experience the collimation information tends to jump around and I found it frustrating to use. I tried collimating my C8 with it and ended up giving up. I could do much better doing it the old fashioned way with star tests. Your mileage may very.

That is not to say that the collimation portion is worthless. In particular, I like looking at it with my best frames from a shoot. If the value is high that tells me I need to collimate even if I don't use the tools here to do it.

The tilt section could be very valuable if I actually had an adjustable focuser. I don't currently but I have heard many people used it successfully for that purpose, and it is easy to use.

What I REALLY like about this program is characterizing the curvature of my system. It is very enlightening to see how changing focus away from best at center can really help your overall FWHM.

#3 orlyandico

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Posted 05 October 2013 - 10:20 PM

Hm. I was thinking of buying it for the collimation alone but in my experience with my trial the collimation does jump around a lot.

What is a "satisfactory" reading? I was getting 6" which - maybe? - is satisfactory but I still got funky stars on my images. Can't be sure it can be trusted..

Of course I could go get a DMK and use MetaGuide, but then the money outlay would be comparable to just using CCDInspector with my main camera. Except that if CCDInspector doesn't work well for collimation, it's a moot point.

#4 jrcrilly

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Posted 05 October 2013 - 10:22 PM

I can think of 5 main uses for this software:
1) Collimation
2) Eliminated Tilt (with adjustable focusers)
3) Determining best focus to minimize curvature
4) Determining best spacing with reducers to eliminate curvature.
5) Grading images.


You can add to that a popup (if you use Maxim/DL or CCDSoft) showing derived FWHM for each frame as it is captured (good for observing focus changes with temperature) and, if you use CCDStack2, the excellent CCDIS alignment method is made available when stacking for no additional charge.

I never shoot without CCDInspector running.

#5 CounterWeight

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Posted 05 October 2013 - 11:29 PM

Thanks Madratter, Orlando, and Jon- :)

I can understand some variability, but only to a point I guess. I don't get single steady consistent numbers for my FWHM or HFD (what MaximDL uses). This with the 3-4 second exposures I use for focus runs. And I don't mind taking a few minutes to get it nailed. What I see is the relative dip when I am in the CFZ (I focus manually but we are talking very tiny nudges on the 10:1 knob)and then rise on each side in and out. But even without nudging focus the numbers jump around a bit. By way of mentioning that what I am getting at is that the sky is unstable here.

The scope I'm getting does have a focuser with tilt adjustment and I've been told by all it is an important feature. The CFZ is about 20 um, much tighter than I have had to deal with on anything till now.

What would I think be helpful is if the software helps more than hinders with a collimation? I can understand this is a difficult proposition as IMO collimation is all method, and scopes can have their own personality about it in ways. One criticism of it was that the information it gave for collimation was 'unclear'. IMO collimation can be touchy enough the first go around without something making that worse?

#6 jrcrilly

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Posted 05 October 2013 - 11:41 PM

What would I think be helpful is if the software helps more than hinders with a collimation?


I consider the collimation figures on normal light frames to be just another watchdog feature; if it changes something is wrong. For actual collimation I'd be more likely to use one of the real time modes available in CCDI (though I believe those are dependent on having Maxim/DL or CCDSoft available).

#7 CounterWeight

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Posted 06 October 2013 - 06:37 AM

Hi Jon,

I have MaxImDL 'pro' level though I don't pay the yearly fee and I think last update was maybe over two years ago, use it on the capture box out at the mount / pier for all my CCD related stuff - and that is where I'll be using the software.

Madratter, I do my image quality eval in MaxIm as it has a 4 parameter measurement, in looking I think MaxImDL does most of the other metrics and eval needed for stacking so those parts aren't really of importance to me either.

What interests me also is their bullet that you can use it for checking field illumination for you chip using flats or star fields, and prediction for different imaging chips.

#8 Madratter

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Posted 06 October 2013 - 10:15 AM

I forgot to mention that predictive feature. I knew about it, but it isn't important to me. I can see where it would be a big help to some considering a different camera.

FWHM (and HFR) will jump around due to seeing, especially with short exposure times. I focus manually using HFR in SGP or Nebulosity and basically if you are close you need to look for the minimums.

If you have no other grading software, this ability in CCD Inspector would be very useful.

I personally found the collimation feature here more a hindrance than a help with my C8. However, if I recall correctly it can be used with other control software. You just point it to where the images will be.

BTW, there are two collimation methods it uses. One is a defocused star and the other is using a rich star field. I tried both without success.

#9 Madratter

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Posted 06 October 2013 - 02:59 PM

Here are a couple things that may not be initially obvious. First the columns shown in the main screen are configurable. You do not have to stick with the defaults. Here I have added Collimation and Temperature.

This is pretty obvious but if collimation is consistent, then it is probably fairly accurate. On this particular run it was. Notice my FWHM going down as time went on. This is because the object was climbing and getting bounced around less.

You can get things like curvature maps on either a single file or you can select a number of files and it will average them.

Attached Files



#10 Madratter

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Posted 06 October 2013 - 03:09 PM

With collimation, there are two crosshairs in the center of the curvature screen. If you are close as is true here, then they will merge together and that will not be obvious. If you right click on the curvature map and select "Magnify Crosshair" it will do just that and make it much more obvious in what direction you are off. If it doesn't bounce around, you can be pretty confident in the answer it is giving. That happens to be true here for these frames.

An obvious question is how good do you need to be. The documentation states that 10 arc-seconds off can cost you about 1 arc-second FWHM. That is pretty bad. On the other hand, they state the goal is to get to just a couple arc-seconds, which is excellent collimation. So on this night, my collimation was more than acceptable.

Attached Files








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