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Support (Please note, this is primarily a user forum, for direct Atik support, please email support@atik-cameras.com) => 3- and 4-Series Cameras => Topic started by: niteman1946 on January 19, 2013, 04:52:25 pm

Title: Vignetting Problem with Optical Train
Post by: niteman1946 on January 19, 2013, 04:52:25 pm
Hi group,
I (finally) have a full complement of components for CCD work.   :)

This shows my optical setup of Meade 12”LX200 Classic, Feathertouch focuser, Meade f/6.3 FF/FR, Mitsuboshi OAG5 off axis guider, Atik EFW2 (w/1 ¼” mounted filters) and Atik 383L+mono.  In between the major components are adapters, spacers, etc.
http://www.astrobin.com/full/30273/?mod=none
The distance from the focal reducer back shoulder to the focal plane of the CCD is 108.3mm.  Depending upon whom you ask, this value should be either 105mm or 95mm.  With 105mm the calculated focal ratio is f6.11.  And with 95mm the focal ratio is f5.53.  Based on the scale of the image, I’m inclined to believe that the 105mm value is correct. :P

But on to my issue,
This is an un-stretched image of the Master Flat taken through this setup and processed in PixInsight.
http://www.astrobin.com/full/30266/?mod=none

And this is the same Flat selectively stretched to highlight the sharp edge of the vignetting.
http://www.astrobin.com/full/30267/?mod=none

And this is an integrated image of M78 with an auto-stretch.
http://www.astrobin.com/full/30268/?mod=none

Even with the Flat (and Bias and Dark), I’ve had no luck processing the corner features out of the M78 image.  PixInsight has multiple tools, but none have provided an answer with my skill set. So far, my only solution has been to crop out the left and right sides of the image. :'(
Any thoughts on a better or different approach?
Thanks,
Mark
Title: Re: Vignetting Problem with Optical Train
Post by: topboxman on January 19, 2013, 05:06:09 pm
Hi Mark,

Perfectly normal. That's how telecompressor works.

I get the exact same thing with my slightly larger CCD of SXVR-M25C, Celestron F/6.3 FR and C-8.

To fix it is by either cropping the image or applying flats.

I love PixInsight and I use every possible tools EXCEPT calibration. I never have good luck with PixInsight's calibration. I use Nebulosity for calibration and then I use PixInsight for everything else.

If you still have problems, can you upload one light sub, stack of bias, dark and flat. Zipping all files would probably be a good idea.

I have the same Hutech OAG-5 as yours. I love it. I have Helical focuser for the guide port and I also love it. I highly recommend Helical focuser.

Peter
Title: Re: Vignetting Problem with Optical Train
Post by: niteman1946 on January 19, 2013, 06:28:54 pm
Thanks for your response, Peter.

Am I correct in understanding that Nebulosity might do a better calibration job than PixInsight?

Looks like uploading zipped files for the Bias, Flats, Darks, and Lights in SendSpace (alternatively in PixInsight's Endor) is going to take forever.  Zipped files of half the stacks will likely take around 8hrs.  My upload is really slow, sorry.  That means your downloads will take a substantial time.  Is it worth the effort?

Mark
Title: Re: Vignetting Problem with Optical Train
Post by: topboxman on January 19, 2013, 06:56:04 pm
Hi Mark,

I just don't think I am using PixInsight calibration correctly. Nebulosity is easier and quicker. I am suggesting to try a different software to see if you get different results. I use Bad Pixel Mapping and I can't get BPM'ed images to work with PixInsight so I gave up. BPM works better than dark subtraction with Sony CCD cameras.

Uploading images is always slower than downloading images. I am not asking for every single sub of bias, dark and flats, just a stack of each and only one light subs totaling four files. For me it probably take me about 30 minutes to upload but probably less than 5 minutes to download. Don't worry about it.

Is your last image calibrated with flats?

Peter
Title: Re: Vignetting Problem with Optical Train
Post by: niteman1946 on January 19, 2013, 07:40:38 pm
Thanks Peter,

Sorry to be so dense,
do you want my Masters in Flats, Bias and Darks?  Or do you want a few each of the individual Flat, Bias and Dark subs?

Yes, the M78 image was fully calibrated, aligned and integrated in PI.

Thanks,

Mark
Title: Re: Vignetting Problem with Optical Train
Post by: topboxman on January 19, 2013, 08:02:37 pm
Yes, Masters in Flats, Bias and Darks and one light sub totaling four files.

When I said a stack, I meant Masters.

Did you check every single sub of bias, darks and flats before creating a Master of each? Sometimes there can be at least one bad sub due to a glitch during download from camera to computer.

Peter
Title: Re: Vignetting Problem with Optical Train
Post by: topboxman on January 20, 2013, 12:19:45 am
Hi Mark,

Just to be on the same page, your camera has a mechanical shutter which means you may need to expose about a minimum of three to four seconds when taking flats to avoid shutter shadow effect. When taking flats, make sure the peak is at about the middle of the histogram. I used to look for maximum ADU of the image but now I rely on histogram and get good results.

Peter
Title: Re: Vignetting Problem with Optical Train
Post by: niteman1946 on January 20, 2013, 04:46:06 am
Hi Peter,

1. I have reviewed each of the flat subs.  All look good.
2.   4sec appear to be the safe minimum period for flats.  3sec or shorter tend to run into the shutter issues.  My flats were shot at 5sec.
3.  Here are the Master files along with one Light file.

http://www.sendspace.com/file/jkk6dz
http://www.sendspace.com/file/l7v5bn
http://www.sendspace.com/file/4l3k4x
http://www.sendspace.com/file/42cmuu

Mark
Title: Re: Vignetting Problem with Optical Train
Post by: topboxman on January 20, 2013, 05:37:26 am
Hi Mark,

The first two has issues downloading. I am able to download the last two in your list. Your flat looks really clean when opened with PixInsight.

I forgot that if you created a Master with PixInsight, I will not be able to calibrate with Nebulosity because Nebulosity cannot open FIT files created by PixInsight. So I will not be able to calibrate your light sub with Nebulosity.

Hopefully others will be able to help you.

Peter
Title: Re: Vignetting Problem with Optical Train
Post by: Dave Watson on January 20, 2013, 09:57:28 pm
Hi Mark,

Being having a play with your images in Pixinsight.......ummmm, very odd

The Bias master seems very strange, it is streeked, I use the same camera and don't get anything like this problem.

I both batch pre-processed and integrated your images and I get the same result as you. Its almost as if the Flat master is not being taken into account.

One question, have you created your masters in accordance with the tutorial http://pixinsight.com/tutorials/master-frames/en.html ?

I will keep playing.

Dave
Title: Re: Vignetting Problem with Optical Train
Post by: topboxman on January 20, 2013, 10:31:46 pm
Hi Mark,

I was able to download the first two images this time.

Dave is correct about the Master Bias. It does not look like your Master Dark. Did you capture Bias subs at the same temperature as Lights? What exposure times did you use for Bias? It looks like as if each sub may have RBI (Residual Bulk Image). Maybe try put a 10 second delay in between subs so that ghost image won't be transferred to the next sub.

Are you capturing using native or Atik ASCOM driver? If you are using ASCOM driver and did not upgrade latest Atik ASCOM driver, then older Atik ASCOM driver has issues with taking Bias at less than certain exposure times because of mechanical shutter. The new Atik ASCOM driver now allow fastest shutter speed regardless of mechanical shutter as long as you cover the camera or capture subs in the dark.

I always play it safe by putting a 10 second delay for Flats, Darks and Bias to avoid possible RBI.

Also, are your Master Flat and Dark calibrated with Bias? If so, it might be more accurate to create another set of Master Flat and Darks again but not calibrated with Bias so we can evaluate a little better.

Peter
Title: Re: Vignetting Problem with Optical Train
Post by: niteman1946 on January 21, 2013, 02:02:45 am
Hi Dave,
The Master Bias was taken using Artemis at 0.001 seconds.  I previously used Images Plus to capture bias subs, and Mike Unsold for some reason limits the shortest bias exposure to 0.20 seconds.  What I understand is that the Bias sub should be at the shortest exposure possible.
In both cases the bias subs showed a somewhat darker bottom than top.  When integrated, this became more pronounced.  The streaking is there with either the 0.001s or 0.20s groups.  However it is coarser with the 0.001s.

Would you mind posting an image of your stretched and non-stretched Master Bias?

Your comment about Flats not being taken into account rings true to me.  This has been my opinion “at times” also.  I suspect the fainter the object, the more necessary the stretch, and then the more noticeable the vignetting.  I asked this question of tech support previously.  One thing they suggested was moisture and ice contamination (presumably not on the flats, but on the lights).  I’ve since cooked the desiccants twice to minimize that possibility.

Yes, I do mostly follow Vincent’s summary (mostly).  Actually I have a hard copy of a more detailed summary that Astropixel did on the PI forum.  It no longer comes up unfortunately.  I take one exception to Vincent’s approach.  I do not calibrate the Flat and Darks initially.  I simply integrate both groups and then select calibrate at the Master Dark and Flat section during Image (Light) calibration.  I have tried it both ways with no noticeable difference.

Mark
Title: Re: Vignetting Problem with Optical Train
Post by: niteman1946 on January 21, 2013, 02:18:43 am
Hi Peter,
See my comments to Dave on the Bias.  My records do not show that I cooled the bias subs.  The Bias master I uploaded was made from 0.001s subs.
I had never seen the term RBI and now have come across it twice in one week.  I will make sure there is at least a 10s separation between subs.
I can (and did) take the bias subs at very short exposure (i.e. 0.001s) using Artemis.  Ascom is another story.  I can’t get Ascom Platform 6sp1 to play nice with my scope.  It won’t connect. So I’m staying with Platform 5a until the 6sp1 problem is resolved.

I do not initially calibrate the darks and flats with the Master Bias.  All calibration is done within the Image (Light) calibration operation.  I have tried both ways with no noticeable difference.

Appreciate your and Dave’s help.

Mark
Title: Re: Vignetting Problem with Optical Train
Post by: Dave Watson on January 21, 2013, 01:25:32 pm
I have not heard of RBI either, but as Mark commented I will also take Peter's lead and give a 10s delay for Biases, Darks and Flats in the future, althought I have not had problems todate.

Here are the links for my files

http://www.qdigital-astro.com/dropbox/Bias_Master-20.fit.zip
http://www.qdigital-astro.com/dropbox/Dark_Master_300-20.fit.zip
http://www.qdigital-astro.com/dropbox/Flat_Master_L-20.fit.zip
http://www.qdigital-astro.com/dropbox/L_300-20_i.fit.zip

All files are have not been stretched, I don't have stretched versions of Bias, Dark or Flat masters.
The file L_300-20_i.fit is a batch pre-processed and integrated of M31, that has not been stretched or had any other work done on it.

I use Vincent's tutorial to the letter as it seems to work for me.

The exposure setting for Bias frames should be the minimum that the camera will achieve, for the 383L this is 0.2s. The 383L specification states that this minimum exposure is the recommended exposure to minimise the effects of vignetting, but find the minimum exposure is more like 3-4s to prevent shutter smearing when I take Flat frames.

Dave
Title: Re: Vignetting Problem with Optical Train
Post by: niteman1946 on January 21, 2013, 04:43:26 pm
Hi Dave,
Interesting stuff.  Are you running anything similar to my optical train setup?  That is 12”LX200, FF/FR, OAG, EFW2, Atik?  How are you setup?
I do suspect that my setup is causing this vignetting.  Although, although …., I was informed that F5.0 or greater should not suffer this.  Oh well.

1. Bias:  Your bias master looks different than mine.  Yours is more normal (even), with brightening along each vertical side.  Mine has moderate to heavy darkening towards the bottom 1/3rd, and streaks.   My bias subs were taken using Artemis at 0.001s and no temperature control.  However, I also have bias taken with IP at 0.20s and -10C.  My IP bias master still shows darkening in the lower 1/3rd, but much smoother - overall similar to yours.
a) What was your exposure? (0.20s ?)
b) What was your temp setting? (mine was OFF)
c) How many bias subs were used? (20 ?) (mine was 30)

2. Dark:  Your dark master does show darkening in the lower 1/3rd , just like my Bias master.  My Dark master is uniform throughout.  Sure you didn’t accidently switch the two?
a) What was the exposure? (300s ?) (mine was 600s)
b) What was the temp setting? (mine was -10C).
c) How many subs were used? (20 ?) (mine was 30)

3. Flat:  Your flat master looks good.  I can selectively stretch in PI and see that there is no sharp edge to the vignetting.  Whereas mine does show a sharp edge (see my original post).
a) What was the exposure? (3-4s ?) (mine was 5s)
b) What was the individual sub ADU value? (25K-35K ?) (mine was about 30k)
c) What was the temp setting? (mine was -10C).
d) How many subs? (20 ?) (mine was 30)

4. M31:  Damn, that looks good!  That wasn’t taken with a large scope, no?

Mark
Title: Re: Vignetting Problem with Optical Train
Post by: Dave Watson on January 21, 2013, 06:11:57 pm
Hi Mark,

My setup is Tak FSQ85 / EFW2 with Baader 2" filters / 383L+, for these images I didn't use my reducer.

When I take Flats I always use a Electroluminescent light source and add sheets of paper to get the required exposure of not less than 5s, I found that anything less than 5s gave shutter smearing.

I always take Biases,  Flats and Darks at the same temperature as I take the Lights at, in this case -20C, so all where taken at -20C.

See below for answers in RED.


Dave


1. Bias:  Your bias master looks different than mine.  Yours is more normal (even), with brightening along each vertical side.  Mine has moderate to heavy darkening towards the bottom 1/3rd, and streaks.   My bias subs were taken using Artemis at 0.001s and no temperature control.  However, I also have bias taken with IP at 0.20s and -10C.  My IP bias master still shows darkening in the lower 1/3rd, but much smoother - overall similar to yours.
a) What was your exposure? (0.20s ?)0.1s
b) What was your temp setting? (mine was OFF)-20C, ALWAYS same as Lights
c) How many bias subs were used? (20 ?) (mine was 30)35, 30 should be OK

2. Dark:  Your dark master does show darkening in the lower 1/3rd , just like my Bias master.  My Dark master is uniform throughout.  Sure you didn’t accidently switch the two?Have checked, no they are correct
a) What was the exposure? (300s ?) (mine was 600s)Same exposure as the Lights, in this case 300s
b) What was the temp setting? (mine was -10C).-20C
c) How many subs were used? (20 ?) (mine was 30)35

3. Flat:  Your flat master looks good.  I can selectively stretch in PI and see that there is no sharp edge to the vignetting.  Whereas mine does show a sharp edge (see my original post).
a) What was the exposure? (3-4s ?) (mine was 5s)6s for the L
b) What was the individual sub ADU value? (25K-35K ?) (mine was about 30k)I always check the corners and the centre of the Flat and make sure they both are between 23K and 33K, generally they are 25K-29K
c) What was the temp setting? (mine was -10C).-20C
d) How many subs? (20 ?) (mine was 30)35, but in actual fact because there is a lot more signal 12 would have done

4. M31:  Damn, that looks good!  That wasn’t taken with a large scope, no?No I used my FSQ85 at FL 430mm @ f5.6
Title: Re: Vignetting Problem with Optical Train
Post by: bwa on January 22, 2013, 01:59:30 am
Hi Peter,

1. I have reviewed each of the flat subs.  All look good.
2.   4sec appear to be the safe minimum period for flats.  3sec or shorter tend to run into the shutter issues.  My flats were shot at 5sec.
3.  Here are the Master files along with one Light file.

http://www.sendspace.com/file/jkk6dz
http://www.sendspace.com/file/l7v5bn
http://www.sendspace.com/file/4l3k4x
http://www.sendspace.com/file/42cmuu

Mark

Mark,

Is there a way to download these files w/o installing yet another piece of junk software on my PC?

bwa
Title: Re: Vignetting Problem with Optical Train
Post by: Dave Watson on January 22, 2013, 09:17:13 am
Hi Peter,

1. I have reviewed each of the flat subs.  All look good.
2.   4sec appear to be the safe minimum period for flats.  3sec or shorter tend to run into the shutter issues.  My flats were shot at 5sec.
3.  Here are the Master files along with one Light file.

http://www.sendspace.com/file/jkk6dz
http://www.sendspace.com/file/l7v5bn
http://www.sendspace.com/file/4l3k4x
http://www.sendspace.com/file/42cmuu

Mark

Mark,

Is there a way to download these files w/o installing yet another piece of junk software on my PC?

bwa

Just click on the link "   Click here to start download from sendspace", no software needed.

Dave
Title: Re: Vignetting Problem with Optical Train
Post by: niteman1946 on January 22, 2013, 05:27:02 pm
One question, have you created your masters in accordance with the tutorial http://pixinsight.com/tutorials/master-frames/en.html ?

Dave

Hi Dave,

FWIW, I went back and followed Vincent's tutorial to a tee.  No luck.

Mark
Title: Re: Vignetting Problem with Optical Train
Post by: bwa on January 22, 2013, 10:54:57 pm
Hi Peter,

3.  Here are the Master files along with one Light file.

http://www.sendspace.com/file/jkk6dz

Mark

Mark,

Was the cooling working on your CCD?  I downloaded your Light.  It is probably one of the noisest images I've ever seen!  Just curious if this is typical of the 383L camera?  If it is, I'm wondering how Darks are working to clean it up?

bwa
Title: Re: Vignetting Problem with Optical Train
Post by: bwa on January 22, 2013, 11:23:08 pm
I did take a fast pass at your Light image. 

I used GradientXTerminator to reduce the vignetting.  With a bit more effort I could probably eliminate the remaining "shadow".  The vignetting is significant but not unlike vignetting I've seen with similar combinations of scope, reducer and camera (http://tinyurl.com/bwaReducerVignetting (http://tinyurl.com/bwaReducerVignetting)).  To further reduce the vignetting I'd suggest reducing the camera to reducer distance; however, this will increase the f ratio.
Title: Re: Vignetting Problem with Optical Train
Post by: niteman1946 on January 22, 2013, 11:43:37 pm
Mark

Was the cooling working on your CCD?  I downloaded your Light.  It is probably one of the noisest images I've ever seen!  Just curious if this is typical of the 383L camera?  If it is, I'm wondering how Darks are working to clean it up?

bwa
Hi bwa,
I use Images Plus Camera Capture and had the cooling turned on to -10C.  When I look at the Image Properties window in IP, it reports a set and CCD temp of -10.04C.

Would you mind describing to me what you see that suggests noise/no cooling?

Thanks,

Mark


Title: Re: Vignetting Problem with Optical Train
Post by: bwa on January 23, 2013, 09:02:00 am
Would you mind describing to me what you see that suggests noise/no cooling?

Mark

The attached 100% crop out of your Light sub is just full of specks/hot pixels/etc.  I consider this a very noisy image!

bwa

Title: Re: Vignetting Problem with Optical Train
Post by: niteman1946 on January 23, 2013, 01:23:22 pm
I did take a fast pass at your Light image. 

I used GradientXTerminator to reduce the vignetting.  With a bit more effort I could probably eliminate the remaining "shadow".  The vignetting is significant but not unlike vignetting I've seen with similar combinations of scope, reducer and camera (http://tinyurl.com/bwaReducerVignetting (http://tinyurl.com/bwaReducerVignetting)).  To further reduce the vignetting I'd suggest reducing the camera to reducer distance; however, this will increase the f ratio.
Thanks Brian,

Pity there's not a GradientXTerminator plugin for PixInsight.
I appreciate what you are saying about modifying the setup.  I can move the camera closer to the focal reducer by about 7.5mm.  Might be worth a try.
I also suspect that my Feathertouch focuser is problematic due to its length.  But would hate to loose it.

Mark
Title: Re: Vignetting Problem with Optical Train
Post by: niteman1946 on January 23, 2013, 01:27:32 pm
The attached 100% crop out of your Light sub is just full of specks/hot pixels/etc.  I consider this a very noisy image!
bwa

Thanks Brian,
That's what I suspected.  Just wanted to be sure.
I'm running this directly by tech support for their thoughts.  Will followup when I hear back from them.
Mark
Title: Re: Vignetting Problem with Optical Train
Post by: Dave Watson on January 23, 2013, 06:24:24 pm
Hi Brain & Mark,

Yes I agree with Brian all the images, darks, flats and lights, seem very noisy to me...this is not normal with the 383 camera....I don't have a problem with this camera at either -20C or -10C(see the example links I posted).

Mark, don't forget that you can't just start changing the distance between the reducer/flattener and the camera sensor ad lib, you have to abide by the metal backfocus of the reducer/flattener as specified by the manufacturer.

Dave
Title: Re: Vignetting Problem with Optical Train
Post by: niteman1946 on February 16, 2013, 02:29:53 pm
Hi Dave, Brian, Peter et al,

Looks like there have been two separate issues (or maybe related) at work here.

Low Voltage:  The Atik recommended 12v power source was producing maybe 12vdc, or just under 12v.  I moved to the Pyramid 13.8v RPS and the "noise" problem went away (so far, and I think).

Reverse Vignetting:  This one is a little more weird.  This was chronic both before and after adding the EFW2 filter wheel (so no fault there).  It happened most of the time, although some images were fine.
  This latest go 'round had me shooting Ha of a portion of NGC2237.  The reverse vignetting was there in my calibrated subs and there in the finished product.  However, once I redid my Darks, Bias and Flats using the Pyramid 13.8v RPS, the Ha image was fine.  So "low voltage"?  Not sure.
  I then followed the same routine for the OIII image.  Used the same new Bias and Dark as Ha, but of course a new OIII master flat.  The reverse vignetting was back.  Reflecting on my life and the fact that tech support and I were running out of ideas, I decided to try the Ha master flat with the OIII image.  And the reverse vignetting was gone.  I did the same using the SII master flat with the OIII image and got good results.  So, the problem (at least in this case) was in the OIII flats.
  There were two noticeable differences between the Ha flats and the OIII flats.  The Ha exposure was at 8s, while the OIII was at 20s.  Both were shot using the t-shirt method with an attempt to achieve 25kADU value.  I used Images Plus (my capture software) to review the subs' statistics.
In both cases (Ha and OIII) the average ADU was around 25k.  But while the Ha max value was around 49k, the OIII max value was at 65,535, which I believe is the maximum. 
I reshot the OIII flats at 8s and monitored the images so that the average ADU was 25k and observed that the maximum stayed around 49k.  The reverse vignetting for the OIII image was gone.
  It appears the high maximum ADU had been the problem.  But, as with the voltage issue, time will tell.  I had not read anything suggesting that this could happen, and when it did would be a problem.  It was more dumb luck that I tried the Ha flat with the OIII image and found success.

Appreciate any thoughts you guys might have on this.

Thanks,

Mark
Title: Re: Vignetting Problem with Optical Train
Post by: niteman1946 on February 21, 2013, 01:16:29 pm
Sorry to persist with this thread, but one more point on the "reverse vignetting" phenomenon.  That is where the corners of the image over-brighten following calibration.
1.  It occurs if the flat sub's ADU value has reached 65k, even if the average is around 25k.  See my previous post.
2.  It occurs if the Light sub's temperature is higher than the Flats/Bias/Darks temperature.  My experience was with the Lights around +10C (forgot to turn the cooler on) and the F/B/D temps at -10C.  In this case I do not know where the tipping point is.  So far as long as all the temps are set at the same value this problem does not manifest itself.

Anyone seen anything like this with the 383L+mono?  I would like to hear that this is a recognized behavior and manageable.

Mark










Title: Re: Vignetting Problem with Optical Train
Post by: NickK on February 21, 2013, 07:34:34 pm
Hi,
The 383L has a 16bit analogue to digital conversion which results in pixel values of 0 to 65535 (2^16).

Are you normalising with the PI calibration? If the PI capture is scaling then it could be over brightening during the calibration. I understand the maths behind the calibration, but I found the calibrate checkbox behaving different to what I would expect.. I normally do calibrate without a checkbox calibration of flats etc.

I usually run with about ~20-40K values at 3 seconds which is just long enough to prevent the shutter causing a problem for my 383L mono. Note that you must NOT perform any form of histographic manipulation on flats - the need to be linear.

I would run a 3D plot on the image (sliced through and scale the Z axis to 100%, and use 2 elevation) and you should see the shape of the flat. So here's a flat integration slice (Lum filter) used with the M42 on the Pentax... the centre is ~0.46 the outter edges are ~0.40 to show the range:
Title: Re: Vignetting Problem with Optical Train
Post by: niteman1946 on February 22, 2013, 04:45:45 pm
Thanks for your thoughts, Nick.
First of all I'm out of town, so I can't follow-up with some of your points. But I will when I get home.

I started this post in January but as said, the problem has been a problem since the beginning. It has just taken me this long to discern "some" ways to make it occur (examples from my last post).  And now how to avoid it (so far).

I originally thought PI was a contributor. But I ran one of the problem sessions in DSS, and got the same results.

So my concern at this point is whether or not I should have Atik look at the camera. So far no one has said they've seen the same thing and not to worry.

Mark