383L+: Sound of the fan and blooming in 2x2 mode

[Max]

Since last week I'm a proud owner of a new Atik 383L+.
A wonderful device with really low noise 
My old CCD was a ST2000XM.

But I'm wondering about the fan: It sounds funny. The fun is blowing unsteady. It seems that sometimes he is not activated for a short time. Is this behavior regular?

Also I'm wondering about blooming in 2x2 binning mode. In this mode I have  also blooming when I take pictures with  only  1sec exposure time. Is there a extra setting for blooming? This is important for my because I want to operate the CCD in 2x2 mode - and  I really don't like blooming.

Thank you for the answers
Max

[MicroAstro]

The KAF-8300 is a anti-blooming chip, so you shouldn't be seeing blooming. Do you hear the shutter opening and closing (it may be hard to hear it closing as there isn't the definite "click" when it closes)? When the shutter sticks open it can look like blooming on brighter stars, but why that would only be happening at 2x2 is peculiar. I don't see any blooming and I shoot most of my narrowband at 2x2, but there are very small star spikes with the KAF-8300 that I understand is due to the microlensing.

The fan on my 383L+ appears to run more or less steady.
...Keith

[Max]

Keith, thank you for the answer.

The very small stars spikes because of the microlensing are not the problem – there is really blooming in the picture. Thank you for the hint with the shutter. I will check it.

Thanks
Max

[Max]

Now I checked the shutter.

During the connecting to Artemis Capture SW I hear two clicks and I can see how the shutter is working. When I take a picture I hear no clicks – but I see the shutters opening and closing.

Thanks
Max

[Steve]

Hi Max,
You are welcome to email a fits file to support@atik-cameras.com and we can take a look.  Though please allow a few extra days as we closed between Christmas and New Year.
Best
Steve

[Lex]

Hi,

My first 383 was sent back to Atik because the defect shutter and I got it back like new!

The fan always has ups and downs because it needs to adapt its speed to the needs of the peltier cooling stage... So I think there is no need to worry about...


Best

Lex

[Max]

Hello Steve and Lex

Thank you for your response.

1.) Sound of the fan:
There are no small ups and downs. It sounds just like the fun is for a short time not working.

2.) Blooming:
Optic: GSO RC8 with AP0.67 reducer. So the system works with f5.3

2x2 Mode with 900sec. Please have a look to the picture.
Here you can see blooming. The blooming is scaling with the exposure time and is also to see with 120sec exposure time.

Thanks
Max

[Lex]

Max,

I do not know how far you are in AP, the stripes come from the spider of your RC scope..
I can only see a strange artifact on the star with the diffraction spikes; it seems to be doubled?
Perhaps a double star?

Otherwise the image seems OK for me?

Best

Lex

[Max]

Hi Lex

The last days I made a lot of pictures in 1x1 and in 2x2 mode. With different exposure times you can see in 2x2 mode how the blooming grows. In 1x1 mode there is nothing to see – also with very long exposures times.

Please have a look to the picture with only 3sec exposure time.

Thanks
Max

[Lex]

Max,

indeed this is strange; knowing that there is an anti-blooming chip built in....
What about you dark frame calibration, do you use automatic dark frame calibration or do you collect them for a master?
As i said before, I had that problem to, but the artifact wasn't the same. The problem came from the shutter.
Observe the shutter of the camera while not on your scope, it should perform nice clics when closing, if not there could be a prob.... Hope that's not case 

Best

Lex

[riklaunim]

KAF-8300 is known of having horizontal blooming in some cases. Google that

[Max]

Hi Lex and riklaunim

The pictures are RAWs.
I informed the ATIK support team. So let's see whats going on.

Thank you for the hint about the horizontal blooming.

Thanks
Max

[Max]

Hi all

In near future I will get my pictures with a "bigger" scope.
So I have to use the 2x2 mode.
Can I adjust the gain to avoid the blooming in 2x2 mode?

Thanks
Max

[Lex]

Max,

why will you do your exposures at binx2? You will loose quality; or not?
I do not know if there's a way to adjust the gain with the 383?? would be nice to know though 
On the other side it wonders me that you have problems in binx2 with blooming, i do all my RGB exposures with bin2 and never had blooming; really strange 

Best

Lex

[Max]

Hi Lex,

there are two reasons for me to choose the 2x2 mode:

1.) When I take LRGBs than I will do the RGBs in 2x2 mode to speed up. When I do in this way I will have the quality and resolution from the Lum in 1x1 and only the color information  in 2x2. There will be no loose of quality.

2.) In near future I will get my pictures with a "bigger" scope. So I have to use the 2x2 mode because of the resolution of the pixel per arcsec with the larger focus length.

PS:
I informed my dealer also - we are now  waiting on the response of the Atik support.

Thanks
Max