Atik 420M White pixel problem / Help

[Rush]

Dear Star gazers,

This is what i m experiencing  with a New Atik 420 m. Its 3 months old ,couldnt test bvor, bcos of missing TAK spacing rings.

Now rings arrived,focusing is manageable,But ....phew... just cant believe what i see.
The amount of white pixels present in both light frames dark frames are beyond my control.
Please do take a look at this Lightframe.180 sec exposure -10 deg CCD temp.

Anyone out there to lend me some pixel wisdom

Thank U all in advance.
Clear skies
Rush

[Chris]

I'm not an expert, can I just check, is the top image a short exposure of a roof and the bottom image a 10 min dark frame? if so yes it doesn't look right to me even comparing it to my 350D's.

So the cooling was definately working?

Atik 420m? not seen that one, is that the same as the 420L mono? I was looking at those for future hyperstar-ing my C8 and hi-res short frac imaging.

I know its been 3 months but surely it has a 12 month warranty against defects?

Sorry I can't help more

[Rush]

Thanx for ur Interest Chris,Both 180 sec exposure.Same CCD temp and focus. Yes its still within the guarantee period.I was wondering if this happening due to my handling errors .U know i want to avoid a bit of calibration frame work.The company add says ,U can even use it without dark frames" save time"for its low noise. But thats not the case:( with this particular Cam.

The Atik 420 is the first camera in its class to offer high performance regulated cooling, low power consumption and narrow body all in one. It is particularly well matched with the 6 and 8 inch HyperStar systems, where the narrow body and low heat dissipation make a difference, or with short focal lenght refractors, providing a very fast, high definition wide field of view.

Sensor Type: CCD - Sony ICX-274
Horizontal Resolution: 1620 pixels
Vertical Resolution: 1220 pixels
Pixel Size: 4.4 µM x 4.4 µM
ADC: 16 bit
Readout Noise: 4e- typical value
Interface: Mini-USB 2.0 High Speed
Power: 12v DC 1A
Maximum Exposure Length: Unlimited
Minimum Exposure Length: 1/1000 s
Cooling: Termoelectric set point with max  ΔT=-30°C
Weight: approx. 400 gr

Backfocus: 13mm

[cosmojaydee]

To me it seems like a problem with the camera, in both frames its the same pixels that are showing , I would return it to the supplier

[Chris]

To me it seems like a problem with the camera, in both frames its the same pixels that are showing , I would return it to the supplier

Oh yes its exactly the same pixels! I'm guessing those pixels must be dead rather than noise then  

A very good case for sending it back for a replacement I should think.

[Chris]

Thanx for ur Interest Chris,Both 180 sec exposure.Same CCD temp and focus. Yes its still within the guarantee period.I was wondering if this happening due to my handling errors .U know i want to avoid a bit of calibration frame work.The company add says ,U can even use it without dark frames" save time"for its low noise. But thats not the case:( with this particular Cam.

The Atik 420 is the first camera in its class to offer high performance regulated cooling, low power consumption and narrow body all in one. It is particularly well matched with the 6 and 8 inch HyperStar systems, where the narrow body and low heat dissipation make a difference, or with short focal lenght refractors, providing a very fast, high definition wide field of view.

Sensor Type: CCD - Sony ICX-274

Horizontal Resolution: 1620 pixels

Vertical Resolution: 1220 pixels

Pixel Size: 4.4 µM x 4.4 µM

ADC: 16 bit

Readout Noise: 4e- typical value

Interface: Mini-USB 2.0 High Speed

Power: 12v DC 1A

Maximum Exposure Length: Unlimited

Minimum Exposure Length: 1/1000 s

Cooling: Termoelectric set point with max  ΔT=-30°C

Weight: approx. 400 gr

Backfocus: 13mm

Yes it is the same one I was looking at then

http://www.firstlightoptics.com/atik-cameras/atik-420l-ccd-camera.html

Defo send it back, Atik don't often have duff cameras from what I've heard so I'm sure the replacement will be fine

[Uranium235]

This may be a completely normal hot pixel count for this chip. You should take a look at a 8300 chip hot pixel map, it resembles something more like a blizzard.

Try going cooler (-20 and below), that should reduce the hot pixel count slightly. Also, try calibrating your flat with a dark and another flat, you might notice all the hot pixels will magically disappear.

But it would be better to check this against another 420 camera dark to see if this is normal(ish). If you cant find a comparison, fire of a screen shot to Atik and they should be able to tell if it looks normal.

[Rush]

Thanx 2 ur response. Well, this is happening at - 14 deg  C, set point is - 20 -C ( This is the maxi cooling - Finito - no more ice age )

[lensman57]

Thanx 2 ur response. Well, this is happening at - 14 deg  C, set point is - 20 -C ( This is the maxi cooling - Finito - no more ice age )

I do not have a 420 but a 314 and 428 and can not comment on the quality of the 420 chip but to start you may wish to send a bias and a dark frame to Atik support and ask for advice as the number of the white dots seems excessive. Meanwhile you can try a different power supply to power the camera and you may also find that as the position of these pixels seems to be fixed dithering a large number of subs with sigma clipping will get rid of the bad pixels or just applying a bad pixel map during the stacking procedure will give the same results.

A.G

[Rush]

Thanx  2 U all

Yes I did send a fits file of both to Atik.

They are real good and and Promt. Excellent Professionals. Respect.

investigation going on.

Will up date as as soon as i get the  Atik reply.

Meanwhile i changed the extension cabel ( nothing 2 do with Atik ).

Looks  much better .

Clear Skies

Rush

[ollypenrice]

Dither, a bad pixel map, darks or even just a hot pixel filter will 'disappear' those in an instant. It really isn't a problem. On my big Kodak chips I have at least 100x more than that!

Olly

[Rush]

Hi Olly,

Thanx 4 the response, Yes I undestand, know what u mean.

Now after changing the extension chord,looks much better even without substracting the Darks.

But again reappears when I binn 2 x 2 on a 7nm Ha Baader Filter.Then i treid without any filters,just the camera and the Tak optical train,

Frames look pretty clean.

Probably coating defect on Ha filter ? Anway annoying stuff and a time drainer.

"Universe is killing me softly while Human stuff is thundering on my pea brain, no matter where i stay, From Alaska to Tibet,Thundering goes on"

Regards

Clear skies

Rush

[Rush]

Sorry,Forgot 2 enclose the image file.

http://astrob.in/138514/0/

[Chris]

Wow, that looks much better! Looks really cool (no pun intended)