Atik EFW2 light leak...

[Hallingskies]

Just testing the imaging train on a new scope and mount.  Got everything talking to each other OK, but when I tried running a few test darks on my Atik 460/EFW2 combo, they all showed a bright edge to the frames.  After a bit of messing around I found that the cause appeared to be a light leak around the gap between the EFW2 case and its exposed drive motor.  A thin strip of carpet tape around the motor where it goes into the case seems to have cured it.   I don't recall having any difficulties with dark frames in the past but then I usually shoot them at night immediately after (or during) a session.

Just wondered if anyone else has had this problem.  Or am I just being unrealistic in expecting a filter wheel to be totally light-proof in bright daylight?

  

[Davey-T]

Get the same with Atik 314L and EFW2, never bothered to track it down just do them at night.

Dave

[carastro]

I have the same camera and EFW and I do my flats in the daytime, and never had an issue with it.

Anyway, once you have some decent darks, you can file them away and keep reusing them.

Carole 

 

[Hallingskies]

21 hours ago, carastro said:

I have the same camera and EFW and I do my flats in the daytime, and never had an issue with it.

Anyway, once you have some decent darks, you can file them away and keep reusing them.

Carole 

 

If your flats are like mine then they are of fairly short duration, and so I guess they won’t be too badly affected by low level light leaks.  I have put a rubber O ring around the base of the filter wheel motor and tightened up the OAG which was a bit loose.  Those measures seem to have improved things quite a bit.

I had an uncooled SXV-H9 for years and got into the habit of taking a few darks between filter changes - taking darks next day without temperature control was a dead loss.  The 460 is a vast improvement in that respect.   There is so little noise from the camera that if there are no light leaks I am hoping a defect map in Astroart should do away with the need for darks altogether. 🤞🤞🤞

 

[carastro]

Quote

The 460 is a vast improvement in that respect.   There is so little noise from the camera that if there are no light leaks I am hoping a defect map in Astroart should do away with the need for darks altogether.

to be honest I quite often don't use darks with this camera, but as it gets a bit older I find it is useful for hot pixels. 

Yes set point cooling makes a lot of difference, I can just take the darks away from the filter wheel and scope if I wanted to - just put the cap on the end of the nosepiece.  

I use Astroart for processing, but no idea how to produce a defect map, perhaps you would be kind enough to explain what it is and how it is achieved. 

Thanks

Carole 

[Freddie]

In AA you use arithmetic > clip to clip 2000ADU off the bottom of your master dark to create your defect map. That then goes in the defect map section and your master bias goes in the master dark section.

[ollypenrice]

8 hours ago, Freddie said:

In AA you use arithmetic > clip to clip 2000ADU off the bottom of your master dark to create your defect map. That then goes in the defect map section and your master bias goes in the master dark section.

Simple as that, Carole. Works a treat and if your darks are not a perfect temperature match it works even better. This gives me consistently better stacks than using regular darks.

Olly

[Hallingskies]

Wot they said....😁

Although I find the hot pixel filter in "extras" in the AA preprocessing menu, set to around 70%, works pretty well if you aren't too much of a pixel-peeper....

Edited August 15, 2019 by Hallingskies

[carastro]

Quote

In AA you use arithmetic > clip to clip 2000ADU off the bottom of your master dark to create your defect map. That then goes in the defect map section and your master bias goes in the master dark section.

Thanks for the advice Guys, but I don't have a clue what this means.  I really need an idiot's guide. 

Carole 

Edited August 15, 2019 by carastro

[Freddie]

In a bit more detail......

Open your master dark. Select “arithmetic” and then “clamp” (that’s what it says in my AA5, though should be clip) and then “minimum”. Now type 2000 in the left hand box and then “ok”. Save this file as your defect map.

When stacking, place the files in the boxes as described above.

[carastro]

Thanks for your help I have got it now.   So do I just use this as a master dark?  Also do i need one for different lengths/temperatures?

Carole