Atik 383L+ Mono, Power supply and the noise problem

[CCD_Stefan]

Hello,
Now I have 13 Volts, it is all OK.

[andysea]

Hi Taylor. I have a 383L+OSC and it's very picky when it comes to power supply.
I bought step up converter on ebay. It takes +/- 12v in and steps up the voltage to a set point. The output can be regulated from 12v all the way to 35v. So far the output seems to be very stable - I have it at 13v.
I was getting hot pixels galore before using it but now the camera seems to be working better.
Just search DC DC Boost Converter on ebay and you should find a lot of different options.
I also started a thread on CN a long time ago regarding this very issue.

Andy

[taylorgtr1]

I'm running 13.5 v and have not had a problem since. FYI

[gvanhau]

Hello
I have losts of pictures wasted due to this (at least three new moon sesions), at first  I didn't realice that this was a cam problem and only tought this CCD was a lot more noisy than my QHY8L cam.

Lastly I am not takink this cam to the field anymore, and I am using it only at home where I can provide it with a regulated Power supply at 13.2V.

However, I think, Atik should at least tell us which are the upper voltage limits of this cam in order to build a solution we can take to the field.

Geert

[andysea]

Hi Geert. A while ago I started a thread on Cloudynighst about this issue. I think all we can do is make sure that this becomes a known issue or get a different camera. I wasted entire nights of imaging too.

Andy

[Chris]

The best way to demonstrate a camera noise problem is, I believe, to take two bias frames.

Subtract one from the other; what's left is the noise and because there is no light and no dark current there's not much other than camera read noise.  Do this with the same conditions (CCD temerature) as you would use for imaging of course.  No need to spend precious dark sky time doing this.

Try this with the good and bad power supply and send the data to Atik.

Light frames are difficult to evaluate because there are so many other sources of noise, for example a very thin layer of cloud could increase the sky brightness and look like additional noise.

Chris

[gvanhau]

Hello Chris

The problen as far a I see is not readout noise (bias).
Instead, it is like a lot of hot or semi hot pixels arise when power supply is below 12.5V.
I even tried to do darks at the same conditions and they are not representative of the nosie, There must be some light falling on the CCD in order to gate the noisy pixels.

The only way to demostrate the noise condition is to take pictures of the same object at different power supply voltages.

regards
Geert

[afm038]

I've been following this thread with interest, my 383 mono to me seems extremely noisy (set at -20 degC cooling) - the raw fits image straight out of the camera into maximdl look like it's been pebble dashed !

Could someone please post or link to a raw fits image direct out the camera that I can have a look and see if mine is particularly bad ?

I run the camera from a bench "12volt" 10Amp bench supply which gives 13.6 volts. I also tried a standalone mains 12volt 5 amp supply which again gave 13.6 volts, there is little or no difference between either images when in use.

Thanks, Andy

[chrisjbaileyuk]

Andy

This is a recent one of mine at -20C. http://dl.dropbox.com/u/80198246/Tycho%20401725_11%2011%202012_1200.000secs_-20.03C_Light_00000092_Ha.fit. This is after changing power supplies to a much better one, 10 amp which measures 13.2 volts under no load (which made huge improvements). I have gone colder but it does not seem to make much difference and I think other noise gets worse as the cooler works harder.

The "speckles" are annoying but fairly easily removed. I use PixInsights Cosmetic Correction on Auto Detect and it kills 99% of them. Sigma Clip stacking does the remainder.

Hope that helps

Chris

[Lex]

Hi Guys,

I had a similar problem not long ago; a bunch of hot pixels on my captures. The operating voltage should be between 11 and 14 V or so; my setup runs @ 13.8V with no problems.

Before I had a 12V adapter and the origin of the problem was a non conform insulated fan of the primary Newtonian mirror. After swapping out the cooling fan the problem was not really solved. I do use a Fan Heater in my warm room during cold winter nights; this one also had to be replaced. This done; the hot pixels were gone without applying DBE or Cosmetic Correction; last ones can concentrate on more Picture relevant details...

Best

[Gib007]

I just wanted to add to this useful thread that I've just come across the same problem with my ATIK 383L+. It has happened a few times in the past but not as often as now. I use an 85 Ah Marine Deep Cycle battery. I am intending on giving it a 24 hour charge now to see how it fairs but I tend to charge it overnight after every night of imaging. All I power off it is my Avalon M-Uno mount and the ATIK 383L+ at -10°C (about 28°C below ambient so not full capacity!).

On my Avalon M-Uno mount, I have one of those "universal laptop car chargers" to convert the 12V input from the battery to an output of near 15V (realistically it's around 14V). This prevents tracking problems. I thought the ATIK 383L+ didn't need this but I guess I was wrong. I've ordered another (they cost like £10 on eBay, including delivery) and will use this at the 15V setting (should provide about 13.8V) to power the ATIK 383L+. Hopefully that does away with any issues. Sad that I had to throw away last night's M51 Hydrogen-Alpha exposures. They looked like they'd really enhance my current M51 data!

EDIT: I have invested in one of these: http://www.ebay.co.uk/itm/350975904870
It's a DC-DC converter with continuously adjustable output voltage. I'll use it to ensure the voltage reaching the camera is a regulated 13.5V. This will prevent this problem from ever appearing again.