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Interested

Atik 383L+ Problem - Advice Sought!

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Hi all,

I bought an Atik 383L+ in Oct 2011. I haven't used it much and have had a few problems with it:

The images I have taken mostly seem to have alot of light creeping in at the bottom of the images (Image 1). I have discounted light from the laptop having ensured the laptop is shielded from my setup. I also use the 'night vision' facility in Artemis. I say 'mostly', as when the light isn't creeping in at the bottom of the image I get the effect in the second image (Image 2) attached! The images were taken using an Atik EFW 2 filterwheel and 2" Baader filters (images attached, using the 'L' filter, but get the same problem with the RG&B as well). Both these images were taken in the same session (one after the other in fact!) so the conditions were the same for both images.Images 1 & 2 are 300 sec guided.

I suspected a intermittent shutter fault so took a 3 second 'dark' with the camera lens cap off (I know the shutter isn't meant to be light proof) to see if the exposure would be 'even' (Image 'Dark' attached) - it wasn't. I use darks taken with the lens cap fitted when I stack in DSS but still get a final image as seen in 'Image 1' or 'Image 2'.

Has anyone any idea what the problem could be? :p

I am loath to send the camera back to Atik until I have ensured the problem isn't being caused by my doing something stupid! :)

Thanks to all :)

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Edited by Interested
more detail addedd

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Hi Pete

Have I got this right?

Image 1 and 2 are taken under identical conditions, and image 2 doesn't have the light leak?

Then to me this suggests something is intermittant?

Is the camera mechanical shutter reliably opening and closing?

Or the filter wheel not indexing correctly?

You could try to find the light leak using a pen torch, this would show on short exposures I would think?

By the way, what is the effect in the second image you refer to?

To my eye there isn't a problem with image 2 apart from some vignetting?

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Image 2 looks OK to me as well, apart from the vignetting.

You took a dark with the lens cap off, then that would be a light no?

Can you take and post a dark with the lens cap on and then you would see if your actually getting a light leak from elsewhere.

Edited by Spikey

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Thanks both, for your inputs. :p

Image 1 & 2 are from the same session. As pointed out, the 2nd image has what appears to be vignetting, which is a bit of a surprise as I am using 2" filters.

The 'dark' I took with the cap off is just to show that, with the shutter closed there is a bad light leak on the shutter (not sure if this would be classed as normal?). If the shutter isn't closing properly, it might be the cause of my problem?

The darks I use for stacking with the exposures in DSS are taken with the lens cap on so don't exhibit light leak.

Attached is an even worse light leak from a session on M 42 back in Jan. I thought the problem then might just be over exposure (5 min guided) but not sure that would explain the arc of light at the bottom of the image?

It might help if the instruction manuals that come with the cameras were a bit more comprehensive :)

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Strange problem.

Try taking some images without the filter wheel, if you still see leakage have a go with the pen torch as I suggested.

Regarding the vignetting, are you able to get focus on the atik using the meade focuser without the diagonal?

If so I would guess the focuser tube is sticking way out the back of the OTA and is cutting into the light cone?

Take a squint down the tube and see if it evenly illuminated.

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Hi Michael,

The M 42 exposure was taken with my ED 80 using 1.25" filters, a 0.8 Reducer/Flattener and a manual filterwheel. I bought the Atik EHW 2 filterwheel and 2" filters thinking it might cure the problem.....wrong!

I can get focus ok with the Meade, I just plug the R/F straight into the tube. Can get focus ok without the R/F as well. I have the light problem in all situations.

It would help if Atik suggested some settings when using their cameras with their software (Artemis Capture), but, they don't.

I've now returned the camera to Atik so will update once it is returned to me.

I am quite open that it could just be the way I am using the camera but without 'suggested settings' I don't know.

I have never had problems with my Atik 314 though. :p

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resurrect time...

is the op still active? and was this ever resolved, as i have just started to suffer similar effects to a light leak, im suspecting a dodgy USB cable somewhere as it doesn't seem to happen when i bench test the CCD

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First thing todo with that sort of thing is fit the metal camera cap and take a long exposure dark. That demonstrates if it's a camera issue or something further up.

A dodgy USB cable isn't likely to cause a gradient as the data transmitted is digital bytes unless it's the power.

The KAI chip is a full frame chip. It means that the image is read by moving the CCD charge one row at a time down the sensor and reading the last row. The result is that if there's light incoming into the sensor (i.e. the shutter or something else) then the image at the furthest point of the reading takes longer to move over the chip and would see a gradient.

Edited by NickK
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Many thanks, back to testing, sounds like it may be the shutter then, as i took a series of darks on the bench and there was no sign of the defect. 

will try with the metal cap on and via the usb hub

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resurrect time...

is the op still active? 

We don't think so. This discussion is nearly four years old and the OP hasn't posted since March. 

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I know this reply may be coming too late but I would like to comment that I had an identical problem with my 383L and I noticed the shutter was intermittently failing to close properly, leaving a narrow opening at the bottom that widened to leave an open triangular wedge in a corner through which if I shone a torch I could even see part of the circuit board.I phoned up Atik and sent off an email with a jpg showing the shutter ajar and they asked to have it back for repairs as it was still under guarantee.

I am waiting for it to be returned, hopefully with the shutter behaving as it should. I have read of others having a similar problem with this camera which is otherwise excellent gear. So it seems to be something it is prone to.  

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Had the camera back from Atik after 3 weeks where it had the shutter mechanism changed and declared 100% ok ...but...sorry to say the gradient is still there!  What next ? 

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Systematic testing for light leaks. If you rotate just the camera, the gradient should rotate in the frame you get. If it still is in the bottom part of the frame it's the camera. If you rotate the camera 90 degrees, and the gradient 'moves' to the short edge, you got a light leak. Next, rotate camera + filter wheel. Etc.

If you take a long exposure with the (lens) cap on, this will also reveal light leakage. As said: systematic testing. That's what cloudy nights are for.

Good luck

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I had this problem when I had my Atik 383+ and @RayD put me right, it was caused through the high speed download being checked in SGP, there was also a setting in APT that created the same problem, switch it off and hopefully your problem will go away.

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