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Aurora flatpanel owners, can you check this

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#1 AstroScience

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Posted 16 April 2018 - 09:14 AM

Hi guys, 

I had noticed before that my flat's adu fluctuates, but didn't dig for the cause. Last imaging run I decided to test what's going on and found this:

Right after turning the panel on I started to take Lum flats for about 2 sec long.

The first flat came about 40000 adu but the following flats dropped 80-100 adu each flat frame. By the time I finished 40 flats my last one showed a drop if about 2000 adu.

Then I moved to RGB flats and noted continious drop in adu. It is only after 30 minutes ny last flats became somewhat regulated.

I went to my friend who also use same panel and noticed same behaviour with he's flats .

We both feeding regulated 12v for the inverter.

Can you please check out your flats and see if you notice the same thing.

I contacted Gerd but he says that no one ever complained about this. Maybe no one had a chance  to check it out?



#2 Jeff2011

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Posted 16 April 2018 - 11:45 AM

I operate mine off of battery power.  Will check my flats when I get home tonight.  I take 25 flats at 26000 ADU for each filter.



#3 Stelios

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Posted 16 April 2018 - 04:09 PM

Hi guys, 

I had noticed before that my flat's adu fluctuates, but didn't dig for the cause. Last imaging run I decided to test what's going on and found this:

Right after turning the panel on I started to take Lum flats for about 2 sec long.

The first flat came about 40000 adu but the following flats dropped 80-100 adu each flat frame. By the time I finished 40 flats my last one showed a drop if about 2000 adu.

Then I moved to RGB flats and noted continious drop in adu. It is only after 30 minutes ny last flats became somewhat regulated.

I went to my friend who also use same panel and noticed same behaviour with he's flats .

We both feeding regulated 12v for the inverter.

Can you please check out your flats and see if you notice the same thing.

I contacted Gerd but he says that no one ever complained about this. Maybe no one had a chance  to check it out?

Were you taking them at dusk? Is it possible the illumination was affected by the intensity of ambient light?



#4 Jeff2011

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Posted 16 April 2018 - 06:38 PM

Attached are the sub-frame selector calculated mean value for DN (not ADU) from 2 different cameras.  An ASI1600MM-C (3 second flats)  and an SBIG-STF8300M (8 second flats).  Both are in ascending time order (I double checked).  The ASI1600MM has a stair step up trend while the SBIG has a steady downward trend.  Both sets of flats were taken before dawn while it was still dark.  Looks like it may be more camera related than flat panel related.

Attached Thumbnails

  • FlatsASI1600.JPG
  • FlatsSBIG.JPG

Edited by Jeff2011, 16 April 2018 - 06:39 PM.


#5 AstroScience

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Posted 17 April 2018 - 01:47 AM

Stelios, no ambient light was present, took the flats while it was dark, but even if somehow ambient light was affecting, I should have see an increase in ADU, but instead it drops rapidly.

 

Jeff, thank you for the data, I would say that only 3 dn increase I wouldn't worry. But with your kaf8300 it definitely shows  degradation. I can't think of a way how it can be camera related?

The only thing I can think off, is that maybe the panel was in a car and warm, then I took it out to a cold and while cooling down rapidly it affected the panels light intensity?

I checked my friend's data with different brand camera and he also have adu drop during flats.

 

Here is how my data looks, 40 Lum flats, 5 sec long. 

 

 

Attached Thumbnails

  • Aurora_QSI660.jpg


#6 Jeff2011

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Posted 17 April 2018 - 08:26 AM

That is an interesting theory.   I also took my flat panel from a warm environment (my house) to the colder outside air.  But I did that in both cases.  You could test your theory by taking the flat panel outside and letting it adjust to the temperature before use.  I will do the same next time.



#7 liors

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Posted 18 April 2018 - 08:55 AM

That is an interesting theory.   I also took my flat panel from a warm environment (my house) to the colder outside air.  But I did that in both cases.  You could test your theory by taking the flat panel outside and letting it adjust to the temperature before use.  I will do the same next time.

I`m Sergio`s friend and I was near Sergio the whole night session, My Aurora flat panel was outside the whole night and still had the same issues as Sergio just described.
I also took flats while it was still dark outside. My plan is to check the flat panel by connecting it to a 12VDC converter from a power outlet and will see if that same issue happening again, since that in the imaging site I use 12VDC 85amp battery and I take flats in the end of session so I suspect that the battery is low so the panel voltage consuming might affect its own luminosity, again this is only an assumption.



#8 Seanem44

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Posted 18 April 2018 - 09:31 AM

Not to hijack the thread... but I just became aware of these.  Do you recommend these for flats? 



#9 liors

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Posted 18 April 2018 - 10:32 AM

Not to hijack the thread... but I just became aware of these.  Do you recommend these for flats? 

Overall I think yes!
Especially for modded DSLR`s where the red wave length runs ahead in the histogram, the design of Aurora panel is to balance all three wave length by increasing the blue and green.
For CCD users other brands might do the job as well.



#10 BenKolt

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Posted 18 April 2018 - 12:21 PM

I don't have any systematic results to show, but I have noticed my Aurora flat's histogram peak shift slightly in time particularly after I've first brought it outside.  I think a course of action would be to bring it outside and let it reach temperature (should just take a few minutes) and also to run it for a few minutes before taking flats.

 

At long last I will be imaging tonight, so I will pay more attention to my sequence of flats to see how much change I'm actually getting.

 

However, my question is whether or not this is actually something to even worry about.  The change appears to be small, and integration of flats is usually done with equalizing the flux of each frame.  Would that not compensate for such small variations?  Or is this a bigger issue than I think?

 

Best Regards,

Ben



#11 AstroScience

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Posted 18 April 2018 - 03:14 PM

Thank you Ben, it would be nice to see your results.

The problem is, that the panel, being new and not cheap, should not loose the brightness at all, otherwise I would be looking for a different brand. Secondly, it took about 30 minutes until my panel stabilized. If during my LRGB flats i would loose 300-400 adu, I wouldn't worry, but only during Lum flats I lost 2000 ADU, that is a problem for me, especially with narrowband.



#12 BenKolt

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Posted 18 April 2018 - 05:23 PM

Thank you Ben, it would be nice to see your results.

The problem is, that the panel, being new and not cheap, should not loose the brightness at all, otherwise I would be looking for a different brand. Secondly, it took about 30 minutes until my panel stabilized. If during my LRGB flats i would loose 300-400 adu, I wouldn't worry, but only during Lum flats I lost 2000 ADU, that is a problem for me, especially with narrowband.

Oh, I see.  I wasn't paying close enough attention to the extent of your change in ADU.  That does sound excessive, and I wonder now if you have a defective device.  Sorry you are going through this, but it's just another part of the fun we have isn't it?

 

Anyway, if I see anything in the behavior of my panel that I think may interest you, I'll let you know.

 

Best Regards,

Ben




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