Oh B.......................!!

[Carole]

Looks like I am going to be without a Mono camera for a bit while I get this repaired.  

It does this from time to time, but normally only 1 - 2 subs in an evening, but Sunday night the first decent clear night for ages it did this to 40% of my subs, so instead of getting 4h 20mins of imaging I can only use 2 1/2 hours!!!!

Why they have to put a shutter on at all I have no idea, and it also makes doing flats tricky.  Lovely camera otherwise.  

Neither sub has been processed, but the dodgy one always seem to come out lighter.

1 dodgy single sub


1 OK single sub (unprocessed)

[Mike]

What's happening? Is the shutter getting stuck?

Anyone know why the shutter is necessary at all? Maybe it can be disabled.

[Carole]

Yes it's the shutter sticking.  I have spoken to Atik and sent them the same pictures.  This is what Vince says:

That looks almost like the shutter has come loose on the stepper motor shaft so we'd have a look and see what's going on.

Anyone know why the shutter is necessary at all? Maybe it can be disabled.

I have asked Vince the same question and this is his reply:

The shutter is there because of the CCD type, it's a full frame CCD so it need's to be covered while it is being readout.

Carole

[MarkS]

The shutter is there because of the CCD type, it's a full frame CCD so it need's to be covered while it is being readout.

That's right - just like a DSLR.  It's the penalty you pay for this kind of CCD.

Sorry to hear of your troubles Carole.  It looked like a really nice Rosette as well!

Mark

[Carole]

Thanks Mark.

I have decided to chuck all the subs in together and then do another stack without the dodgy ones and try to make a mosaic of it rather than waste all that data.  Hope it will work.  

This is a narrowband image of the Rosette which I have never done before.  Most of my NB stuff I hardly seem to get any Oiii and Sii results, so decided to try for something bright.  I'm in the middle of processing it all now.  Going to give Atik the camera at Astrofest so will have to make do with my OSC for a little while while I am waiting for it to come back.  or - I bought a small Atik16ic (2nd hand) several months ago for doing galaxies and small stuff which I haven't tried out yet, so this might give me the shove to try it out.

Carole

[Carole]

Atik have taken a look at the camera and said

when the cooling was on full the shutter motor didn't open the shutter fully, I have had to replace the circuit board in the camera

They also said the thread was getting a bit worn on the front of the camera and offered to replace that while they were at it.

Altogether should cost me around £100 with return postage & vat.

Carole

[Mike]

Was it out of warranty?

[Carole]

I bought it 2nd hand Mike about 18 months ago, so yes.

Carole

[Mike]

Ahh that's a shame. Well I guess £100 doesn't sound too bad and a lot cheaper than a new camera.

[RobertM]

I don't think you can complain.  I presume the camera has an unknown lineage so you don't know how many images/shutter operations it's done.  Shutters do wear out and stick and replacement's are not expensive (depending where it's sent).  Yes it is unfortunate but should be expected for this type of camera.

Robert

[Carole]

I am quite happy with the price, and considering Vince tells me they built the camera in the first place (they checked the serial number) I know it's being repaired by the right people - a lot cheaper than buying a new one.  Still don't understand the logic of why larger chips need a shutter though. 

Carole

[MarkS]

Still don't understand the logic of why larger chips need a shutter though. 

It is to do with the circuitry of this sensor. For some designs of sensor, you don't want light continuing to shine onto it while the image is being read otherwise you get image smearing.
See here for a more detailed description:
http://www.sergepetiot.com/?page_id=173

[Carole]

Thanks for the link Mark,
But my QHY8L which is an even larger chip doesn't have a shutter.

Carole

[MarkS]

But my QHY8L which is an even larger chip doesn't have a shutter.

That's true - it uses a slightly different chip design to get around the problem.  In fact the L & PRO versions of the QHY8 use different chip designs.  Quoting from their website (http://qhyccd.com/en/left/page1/qhy8l-8pro/):

QHY8L has a low price than QHY8PRO.
The major different is the CCD sensor. QHY8L using a Two field readout sensor.After exposure the Red and half of green pixel is readout for first.Then readout the blue and another half of green pixel. QHYCCD use technology to keep the two field exposure period the same.  For long exposure there is no difference for them. To capture the fast movement object or fast various scene. We recommand the progressive scan sensor of QHY8PRO.

[Carole]

Woohoo!

My Atik383L is on it's way back to me via UPS.

Cost in the end was £87 including delivery, a service and a new front casing as they noticed the thread was becoming a bit worn.

Carole