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Old 18-08-2014, 05:58 PM
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A small problem I had with my SBIG STXL

I thought it would be prudent to document this problem for anyone buying an SBIG STXL with integrated filter wheel and guide camera.

Over the last 6 months or so I had noticed images every now and then would present like the first image with odd looking artefacts. Allan Holmes from SBIG thought it might have been a clocking issue. The horizontal lines in this dark frame are not supposed to occur and I would see them in my darks and sometimes in lights. It had me worried that I had a lemon on my hands.

I brought this to the attention of SBIG and its representatives who were very responsive to the problem. After some testing it was requested to send the camera back to the States for assessment and repair. When the camera was tested at SBIG they could not find the problem and returned the camera.

Now something to note here. I only sent the camera head and not the filter wheel with integrated guide camera. It took about 4 weeks to be returned to me and I have had it back a few weeks now.

So a week or so ago I decided to test the camera again whilst waiting for an adapter to arrive. To my dismay I was once again getting the same problem with my darks. So I brought the camera home from the observatory and tried the camera again from home. I wanted to narrow down the causes of the problem and wanted to rule out anything at the observatory. With the artefacts appearing at home I knew that the cause was not in the dome via RF or power related possibilities.

So now I thought I would remove various cables until I found the route cause. There is a HDMI cable that connects the integrated guide camera to the main camera. It is quite thick and looks very robust. As it turned out the HDMI cable which supplied with the camera was the cause of the problem. To determine this I first took darks without the cable attached to both the camera and the guide camera. Darks were perfect. As soon as I attached the cable, the darks had artefacts again. Then I used a spare HDMI cable to determine if it was the HDMI cable or part of the main camera or the guide camera. In this instance it was the HDMI cable. The spare cable attached connected the guide camera and also did not create artefacts. The second image shows a typical dark since installing the new HDMI cable.

I don't know why the cable causes this problem, but if you see it on your STXL camera, this might be the cause. I would welcome any theories as to why the cable was causing this. Maybe the earth shield was faulty.
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Old 18-08-2014, 07:07 PM
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MrB (Simon)
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Quote:
I don't know why the cable causes this problem
Inadequate internal screening of the twisted pairs would be my guess, therefore crosstalk between adjacent pairs.
Good work finding the problem, must be a relief!

Last edited by MrB; 18-08-2014 at 07:23 PM.
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Old 18-08-2014, 07:28 PM
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Yep it is a relief that this thing does not have to make a trip to the US again. More inconvenient than anything else. SBIG have been great in dealing with this issue.
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Old 18-08-2014, 08:23 PM
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marc4darkskies (Marcus)
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Thanks Paul. Just ordered mine last week. Nice to know it was a simple fix!

Cheers, Marcus
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Old 18-08-2014, 09:27 PM
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geez Paul, you have so much trouble, Murphys law bites you hard
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Old 18-08-2014, 09:42 PM
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Originally Posted by marc4darkskies View Post
Thanks Paul. Just ordered mine last week. Nice to know it was a simple fix!

Cheers, Marcus
Yes thankfully it was a simple fix Marcus. The actual camera produces good data as you have seen with the IC2944 and the Meat Hook images I did. Just surprised that such a cable would fail.


Quote:
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geez Paul, you have so much trouble, Murphys law bites you hard
I think it is because I am good at bug hunting that I get these little issues. That is the fatalist way of looking at it I reckon. Still ironing out the chinks even now.
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Old 20-08-2014, 11:44 PM
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Excellent detective work!! These sorts of issues can be so frustrating - especially when even SBIG couldn't come up with the solution. One would hope the company would be aware of various issues affecting their products but my experience in this hobby so far is that we are all unpaid beta testers!

Peter
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Old 21-08-2014, 06:19 AM
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Just a little further. This problem has been seen by SBIG before and from another source that the cable seems to be defective. I bought a HDMI from Lindy which is 0.5m long and am using that. I will have to buy a common choke for it, but overall the performance is near perfect at this stage.
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Old 02-10-2014, 08:32 PM
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An update on this issue.

My assessment is that this camera is defective. I have been in contact with SBIG and its representative here for quite some time. To date we have been trying to narrow down the cause of the problem but now I am at an end of bug hunting a camera that ought to work straight out of the box. I requested that the camera be replaced several weeks ago and SBIG have not done so yet. I was asked to conduct further tests which I have gone along with so as to find a cause, but as yet we cannot. Alan Holmes from SBIG thinks it might be sky light making its way into the camera from adjoining filters. That means the camera has a problem in my mind.

As you can see the camera has what is called a wave bar on the left hand side of the image. It moves erratically about on that side of the sensor and cannot be calibrated and as you can see it ruins perfectly good data.

I have included two darks showing what happens. One single sub and a stacked image. As you can see the destruction to the data is terrible.

I am totally disillusioned with this camera and really wish that QSI had its 700 series up and running. I would have bought that right from the start.
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Old 02-10-2014, 08:51 PM
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That sucks, Paul... Hope it is resolved promptly one way or the other.
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Old 02-10-2014, 09:00 PM
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Originally Posted by RickS View Post
That sucks, Paul... Hope it is resolved promptly one way or the other.
You can only imagine how much I am fuming about this problem. After 4 months I am quite ready for a new camera. Like a simmering volcano I am right now Rick. It was easier getting a new worm gear from SB for my mount. Mind you I had to jump through a few hoops to get that replaced too.

To be far though SBIG have been responsive and trying to be helpful, I just want a camera that works though.
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Old 03-10-2014, 10:46 AM
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Ouch, that is nasty!

Hopefully, you get it resolved soon.

H
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Old 03-10-2014, 01:01 PM
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My Apogee U16M was a dud (contiguous bad columns) but to their credit it didn't take too many iterations with support to prove it and they took it back and replaced the sensor. Still took a few months with shipping and waiting for TrueSense to supply a replacement chip. I bought it secondhand so I was grateful just to get it repaired. If I'd waited another couple of days the sensor would have been out of warranty.

Hopefully you'll have a happy ending too, Paul!

Cheers,
Rick.
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Old 03-10-2014, 04:09 PM
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Thanks guys.

Rick I am sure it will work out eventually. Now just complicate things I also get a grid pattern in some of my darks. This I think is RF or EM in my observatory (see dark frame, the thin vertical lines over the entire frame).

Some things that might be causing this are:

  1. Computer is sitting on top of the UPS.
  2. A couple of AC cables (one of which is the camera cable) are coiled loosely
  3. Ethernet over power system. I have 4 units in the observatory.
Any ideas? I have seen this pattern whilst doing darks and the only things with power were the UPS, the camera, Ethernet and the IP power switches. No dew heaters were on.

I would welcome anyone's ideas here.
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Old 03-10-2014, 05:48 PM
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Paul,

How long are the darks? Might be worth taking some data samples in the dark and light areas to compare values. A screen stretch can exaggerate a trivial difference.

I haven't seen anything quite like that except for very short LRGB exposures on my U16M (a few seconds or so) which sometimes demonstrate similar patterns in the low SNR areas.

Cheers,
Rick.
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Old 03-10-2014, 06:03 PM
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30 minutes Rick. Weird yep that is what I thought too.
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Old 04-10-2014, 05:07 PM
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We'll if your that desperate , get serious with diagnostics Paul.
Take the camera home, connect just the camera to pure DC, a battery.
Take a dark/dummy image and evaluate. I understand the cam alone is OK?.
Than add stuff, filter, plug pack etc, electrically and then mechanically , imaging each time until the fault appears.
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Old 04-10-2014, 06:15 PM
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Quote:
Originally Posted by Bassnut View Post
We'll if your that desperate , get serious with diagnostics Paul.
Take the camera home, connect just the camera to pure DC, a battery.
Take a dark/dummy image and evaluate. I understand the cam alone is OK?.
Than add stuff, filter, plug pack etc, electrically and then mechanically , imaging each time until the fault appears.
Took darks last night with no guide camera connected and the filter wheel disconnected electronically.

What I noticed was that with the guide camera HDMI cable removed the wave bar was still really obvious. Then when I electronically removed the filter wheel the problem was far less obvious but still present. So either the daughter boards are faulty or the problem lies in one of the peripherals. I have asked for a complete replacement and it looks like this is what is going to happen. With the change over of company ownership I am at the mercy of the new owners. I would expect nothing will change and warrantee will be honoured.
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Old 14-10-2014, 04:43 PM
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I didn't really want to voice anything about my issues, but I'm dismayed to say I've had a much longer period of various issues with my STXL11K. Peter and SBIG have been responsive, but I'm still not really happy, doing many tests to try and eliminate issues. In the last few months the camera has developed the same vertical lines I can see in these dark frames
[perhaps difficult to see in my attachment]. I was advised by SBIG to use a CCDOPs vertical filter to pre-treat my subs. But it gets extremely complicated to work on the data as what do you do for Flats, Darks and Bias frames? Pre-treat these too? That's hell of a lot of extra work. What to do?

Steve
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Old 14-10-2014, 05:22 PM
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Looks very similar Steve. I have insisted on a new camera and that is being delivered in the next 4-6 weeks as I understand it. That is what I have done.
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