Sensor temperature and calibration

[tooth_dr]

@vlaiv wishing you and the wife a speedy recovery. 

[vlaiv]

Thank you all.

[Ken82]

All the best to you and family Vlad!

your a legend on here and I hope you both recover well.

ken 

[DaveS]

Yes, all the very best to you and your wife Vlad, get well soon.

[fozzybear]

Speedy recovery Vlaiv to you and your wife. Take care and get well soon.

Edited July 27, 2020 by fozzybear

[x6gas]

All good wishes to you and your wife Vlad...  my wife and I have also had it.  I was lucky and was virtually asymptomatic but my wife was in bed for the best part of two months and fully four months after her first symptoms still gets fatigued very easily.  If you are unlucky it's a very, very nasty virus so do rest up... and then rest some more... and when you are feeling properly better... keep resting for a few more days!

[vlaiv]

20 minutes ago, x6gas said:

All good wishes to you and your wife Vlad...  my wife and I have also had it.  I was lucky and was virtually asymptomatic but my wife was in bed for the best part of two months and fully four months after her first symptoms still gets fatigued very easily.  If you are unlucky it's a very, very nasty virus so do rest up... and then rest some more... and when you are feeling properly better... keep resting for a few more days!

Sorry to hear about your wife but good thing she is well now. I've been hearing about some people having problems a month or more after having it. Very nasty virus indeed!

Thank you all once again for your kind wishes!

[Allinthehead]

Wishing you both a speedy recovery and good health to enjoy the new house when it's complete.

[Rodd]

42 minutes ago, vlaiv said:

Sorry to hear about your wife but good thing she is well now. I've been hearing about some people having problems a month or more after having it. Very nasty virus indeed!

Thank you all once again for your kind wishes!

Indeed, there have been lingering effects of paralysis, sttll OK me, weakness.......nothing to take lightly

[Davey-T]

6 hours ago, Rodd said:

PI makes a big deal about it when scaling is employed.

Maxim won't calibrate images if the darks aren't the same temp'

QSI683 has no problem getting down to -20 anytime, usually do it in steps to stop it getting there too quickly 😁  ZWO seems a strange design with rear of camera just empty space with fan drawing air through it.

Dave

[Rodd]

52 minutes ago, Davey-T said:

Maxim won't calibrate images if the darks aren't the same temp'

QSI683 has no problem getting down to -20 anytime, usually do it in steps to stop it getting there too quickly 😁  ZWO seems a strange design with rear of camera just empty space with fan drawing air through it.

Dave

See, I knew it was weak 

[gorann]

6 hours ago, vlaiv said:

Well, I was supposed to have moved to a new house by now together with obsy under dark(er) skies and all - but you know, this year has been tough on all I guess.

Build of my new house not started yet due to all this covid stuff - just some ground preparation works done. I took another project to be able to fund all of that so there is also lack of time for astronomy ... On top of all of that, I'm now in my 10th day of covid infection - luckily both wife and I have rather mild cases, still plenty of rest is needed (and self imposed quarantine as well).

 

Sorry to be late into this thread but I have been busy outside building on a new obsy (good exercise and why only have one when you can have three...). I must join in wishing you Vlaiv and the wife a speedy recovery. Statistically you should soon be fine (99 % confidence) since the nasty lingering symptoms are rare. Clearly you are currently well enough to provide your normal key input on SGL!

Just a small comment on the cooling issue. When looking at the temperature vs noise curves for the ASI CMOS cameras I see little reason to ever strive for a delta T of -45 °C. I have heard that it is rather hard on the cooling system to run it at max, so I usually go for a delta T of about 35°C or less. Here in Sweden I set my ASI1600 at -20°C but then then nights are rarely above 10°C during the astrodarkness season (Sept - April), and when I was in the Australian tropics in December I settled for running my ASI071 at -5°C and there was not much noise to worry about.

So Rodd, with the current increase in global temperatures, maybe you should just settle for -15°C and get a new set of masterdarks😎

[Rodd]

1 hour ago, gorann said:

Sorry to be late into this thread but I have been busy outside building on a new obsy (good exercise and why only have one when you can have three...). I must join in wishing you Vlaiv and the wife a speedy recovery. Statistically you should soon be fine (99 % confidence) since the nasty lingering symptoms are rare. Clearly you are currently well enough to provide your normal key input on SGL!

Just a small comment on the cooling issue. When looking at the temperature vs noise curves for the ASI CMOS cameras I see little reason to ever strive for a delta T of -45 °C. I have heard that it is rather hard on the cooling system to run it at max, so I usually go for a delta T of about 35°C or less. Here in Sweden I set my ASI1600 at -20°C but then then nights are rarely above 10°C during the astrodarkness season (Sept - April), and when I was in the Australian tropics in December I settled for running my ASI071 at -5°C and there was not much noise to worry about.

So Rodd, with the current increase in global temperatures, maybe you should just settle for -15°C and get a new set of masterdarks😎

That’s what I was afraid of. Actually, I have a -18 master dark due to this experiment.  Since 2 degrees off is within the acceptable range I should be good to -16 or so.  It’s not to bad with 300sec subs.   Even less so with shorter subs.  So I guess I am covered. 

[Xiga]

All the best to you and the Mrs @vlaiv. Hope you are both back fighting fit soon 💪 

[Rodd]

22 hours ago, vlaiv said:

DeltaT of 45C is quite decent value really.

Here's one for you.  Last night it was even warmer--around 27.  So I switched cooling from -18 to -16.  I achieved -16 using only 74% of the cooling power.  I was elated.  10 minutes later I look and the cooling temp is -14 and the power is pegged at 100%.  Why would this happen?

[vlaiv]

2 minutes ago, Rodd said:

Here's one for you.  Last night it was even warmer--around 27.  So I switched cooling from -18 to -16.  I achieved -16 using only 74% of the cooling power.  I was elated.  10 minutes later I look and the cooling temp is -14 and the power is pegged at 100%.  Why would this happen?

That one is rather simple

You set your temperature to -16 and said camera to start cooling and went about your business. Few minutes later you returned and was very pleased to see it at -16C with 74% of power being used.

Then you started taking exposures and things changed. Taking exposures makes sensor electronics work something - it is not the same as having sensor sit there idly being cooled. Work that sensor does means increased power consumption of the sensor itself and as a result - increased heat.

Same thing really that happens with car engine. If you put it in neutral and sit there on a parking lot - it's not going to heat up much and ventilator will not even start turning. Take that car up hill and it will soon start to heat properly and ventilator will kick in. Rev that engine very hard and go up very steep hill and there is even a chance that you will over heat it.

Working sensor produces more heat and it is harder to cool than idle sensor.

[Rodd]

7 minutes ago, vlaiv said:

Then you started taking exposures

But I hadn't taken exposures yet.  I was polar aligning and turning on various things--just starting out