Leave all-sky camera on during day?

[michaelmorris]

I'm in the process of building an all sky camera based on a ZWO ASI 120MC camera.  I'll be using it with the stock lens that comes with the camera.  This lens doesn't have an iris.  I'm concerned that daily exposure of the full glare of the Sun on the energised chip on the ASI120MC camera risks damaging the chip.  Is this fear well founded or am I worrying about nothing?

[PhotoGav]

I guess it depends what exposure length you will be using while the Sun is out. If it is very short, then surely there is nothing to worry about - that is the job of the camera after all, to capture light. If it is a long exposure, that might well be different.

What software will you be using to run the all sky camera? I use Allskeye (http://www.allskeye.com/) and with that you can control the active hours, so it only runs from after sunset until before dawn. Great bit of software!

[michaelmorris]

6 minutes ago, PhotoGav said:

I guess it depends what exposure length you will be using while the Sun is out. If it is very short, then surely there is nothing to worry about - that is the job of the camera after all, to capture light. If it is a long exposure, that might well be different.

What software will you be using to run the all sky camera? I use Allskeye (http://www.allskeye.com/) and with that you can control the active hours, so it only runs from after sunset until before dawn. Great bit of software!

Yes, I'm planning on using Allskeye as well.  It looks great. 

Whilst the software will only preview and record images during user set times, surely the imaging chip will still be on.  Also, the exposure length may be set by the software, but, because there is no shutter, surely the Sun will still be shining down on the unprotected chip.

If this is a problem (the subject of this posting) ways around it might be to have a servo-driven lens cap or use a lens with a powered automatic iris.

[PhotoGav]

Just now, michaelmorris said:

Yes, I'm planning on using Allskeye as well.  It looks great. 

Whilst the software will only preview and record images during user set times, surely the imaging chip will still be on.  Also, the exposure length may be set by the software, but, because there is no shutter, surely the Sun will still be shining down on the unprotected chip.

Mmm, yes I see what you mean. I use the Oculus camera and that has an electronic shutter, so nothing covering the chip, and it has been operating perfectly outside for over a year now. So, I conclude that you have absolutely nothing to worry about!

Or should I now be worrying...?!

[michaelmorris]

45 minutes ago, PhotoGav said:

Mmm, yes I see what you mean. I use the Oculus camera and that has an electronic shutter, so nothing covering the chip, and it has been operating perfectly outside for over a year now. So, I conclude that you have absolutely nothing to worry about!

Or should I now be worrying...?!

I presently use a Watec 902H2 Ultimate analogue CCTV camera for meteor videography.  These traditional 'analogue' imaging chips are sensitive to burn-in, so this is protected by both a powered auto iris lens and cutting the power to the camera and lens during the day.  As the auto iris automatically completely closes when the power is off, and the chip is not on, this protects the chip nicely.  I'm not sure if the type of CMOS chip used in the ZWO camera is susceptible to burn-in in the same way. 

[Stub Mandrel]

I'd consider playing safe, although all-sky lenses are pretty small they must create a 'hot spot' in sunshine.

[JamesF]

I agree.  I think I'd want direct sunlight completely blocked from the sensor.  Or at the very least something like an ND5 Baader film filter in front of it.

James

[Davey-T]

I think Gina spent a while working on a way to cover the lens during the day, not sure what the result was.

Dave