Astro photography tool

[The_bluester (Paul)]

I have that set already, the problem is that on re-connection it sets the cooler power to zero and by the time the power ramps up the sensor is up in double digit positive territory.


If it is possible to take the current chip temperature and use that as the target, is it possible to use the existing cooling power as a feed forward/initial setting as well with PID (I presume) control over the cooling resuming after that?

[Yoddha]

It does exactly the same Gets the reported chip temperature and sets it as cooling target... Looks like the driver reports a wrong temperature in this case. Maybe you can drop a line to the ZWO support?

[The_bluester (Paul)]

I thought it was picking up the correct temp, just the cooling power is being set to zero on connection rather than the 45-50% it was running at at the time.

I will test again this weekend and confirm.

Edited to add: this is with the ASCOM driver for the camera, it does not look at though APT currently supports the ZWO native one, though the information in the camera settings appears to be the same as the native driver reports in ASICap.

[Yoddha]

The ASCOM has no way to control the power... It works only with the set temperature and the driver (or the camera itself) decides what to do with the power.

[The_bluester (Paul)]

It sounds as though either ASCOM or the native driver must set the cooling power to zero on initial connection. I will try it direct via ASICap and see how that behaves, but I will only set the temp a few degrees below ambient to be a bit nicer to the sensor.

Does APT control how aggressively the cooling power is changed on initial cooldown or is that by ASCOM or the driver?

[The_bluester (Paul)]

Well I have done some testing, and even ASICAP behaves the same way on reconnection.

Unless some way is found to poll the driver if cooling is active already on connection and have it use the existing power setting then it is just a case of living with it I think. The only time the cooling has stayed on was the crash on flip I mentioned above. I will have to see if I can replicate that crash this weekend.

[Yoddha]

The ASCOM driver (limited by the ASCOM standard) has access to the current temperature and the "set temperature". The idea of Cooling Aid is to cool the camera in small steps "Current to Set" in order to avoid big power push...

But it is unknown how the driver is controlling the power...

I suppose that driver is using initial values like 0% power or 0C set temperature which are set on new connection rather than determining the current values.

[The_bluester (Paul)]

It looks like the native driver is using a PID scheme to control the cooling power. I probably don’t need to worry about it too much, none of ZWOs literature even mention controlled warming at all and the ASICAP program does not have any function to slowly warm the sensor, cooling is on or it is off.

The PID functionality means that the cooling is relatively slow anyway, looks like it has a fair amount of derivative in it so it progressively increases the cooling power rather than just smashing it with a high power setting if you ask for a big reduction in temperature.

I am thinking I should set the cooling steps to zero and let the driver look after that, use the warming aid to slow the rise time on warming it up and stop worrying about the odd occasion when I have an unexpected disconnect.

[Yoddha]

Once we start working on the native ZWO support will investigate the options to keep the cooling load as close as possible to one from the previous connection

[The_bluester (Paul)]

That would be handy, but it does seem that it might only apply in cases of "dirty" disconnects like a software crash. Not being a developer I have no way to tell if the driver is configured to have the choice on if it should turn the cooler off or not in the case of a clean disconnection by whatever application is using the camera.

If you have not been working on native driver support yet I don't imagine you know either at this point? If you can disconnect without turning off the cooling and can reconnect without interrupting the current cooling power then it would be really useful.

An instance I could think of would be if the cam was connected and cooled such as shooting darks or flats but you wanted to change APT from a daytime to night colour scheme without having to warm then cool the camera again, given that action requires a restart of APT.

[The_bluester (Paul)]

I just found an interesting niggle (Minor)

Given I can't do much else at the moment I have the camera powered up in a dark room with caps over the open end of the reducer/OAG/Camera combo to shoot a darks library at various gain settings.

I thought I would get smart and create an imaging plan that started with setting the gain, then cooling the camera, shooting the darks then warm the cam and sleep the PC. That way I can create darks plans easily for a range of gain settings

All well except if I set the cooling steps to 0 to leave it to the driver it cools to the set point but does not close the cooling aid and waits there. If I set a temperature step so APT is in more control of the cooling, it cools to the set point, closes the aid and continues.

Not really an issue now that I know about it, but an oddity nonetheless.

[Yoddha]

Good finding! Will investigate how to fix it, as in this case there is no much feedback to know when cooling has finished...

[The_bluester (Paul)]

The only thing I will have to check is I can not recall if it was requesting a temperature change in that instance or if the sensor was already cooled to the target. I will have a play at home tonight and explicitly try it when the sensor is at the setpoint and again when it is a few degrees warmer to isolate if it is the cooling assistant effectively not starting, or if it finishes silently in the case of setting 0 degree steps.

I was trying to use 0 degree step setting to let the driver run the show as if the steps are small the cooling power is very slow to change and the cooling aid tends to time out. If the driver only allows for APT or other programs to command a setpoint and the driver looks after the power level I might as well set at least 5 degree steps to make the driver react a little more aggressively.

[Yoddha]

Yes, you can set the step to 5 or 10 and get similar behavior to 0 step But will have possibility to know when cooling is finished.

[The_bluester (Paul)]

I think I will just use it like that unless you can find a way to control the cooling more closely when you work on the native driver. The bigger cooling steps help quite a bit with getting a decent ramp in power levels.

[The_bluester (Paul)]

Just a bit of feedback, I have been using the new version with tweaked behavior on guide star loss, much better.

Now I just need a more powerful PC to run the show, the poor little first generation Celeron powered Intel NUC is like watching a glacier move when it comes to plate solving, a couple of minutes at best for ASPS and unless the goto is close you can forget about it when it comes to a spiral search!

[Yoddha]

Hi Paul,

Many thanks for the feedback!

[Yoddha]

APT 3.70 is here! It comes with access to completely new technologies for controlling astro gear – INDIGO / INDI, possibility to use RaspberryPi computers and the commercial products based on them - ZWO ASIAir, QHYCCD StarMaster, StellarMate. Integrated is the Lacerta’s FBC- Flat Box Controller. Added is support for GPS devices and smartphones. To finish the summary will mention the Keys Thingy – another way to enter data without keyboard in the dark.

The usual list of the changes is available here:
http://www.astrophotography.app/news

[Yoddha]

If you are using Nikon camera please update to APT 3.71. It fixes a bug with the long exposures!

In case you are using other camera this fix is not needed.

Apologies for the inconvenience!

[Yoddha]

APT 3.80 arrived! It brings the highly requested native support for ZWO cameras as well as support for Pegasus Astro and ArteSky flat panels, support for more Canon models, support for the latest CR3 and NEF raw files, GoTo++ improvements, mosaics import from HNSKY or CdC and more.

Update your APT and be ready for the New Moon

The usual list of the changes is available here:
http://www.astrophotography.app/news