×
INDI Library v1.8.5 Released (19 Apr 2020)

April 2020 release of INDI Library v1.8.5 introduces new drivers while providing fixes and improvements to existing devices and core framework.

Tempereature in DSLR subs?

1 year 4 months ago
mlarsson
Platinum Boarder
Platinum Boarder
Posts: 402
Karma: 1
More
Topic Author
Tempereature in DSLR subs? #33566
Hi!

I'm curious about the temperature data in DSLR subs. When I download subs from my Canon 1000D, there is a FITS keyword CCD-temp, filled in with a temperature. WHen I download CR2-files, the raw files, I cannot find any information about temperature in the EXIF-tags of the images.

So where does the FITS-keyword information on temperature come from? My belief was that the fits-files were converted form the cr2-files - and if the cr2-files do not contain information about temperature, where then does it come from? Or do the CR2-files contain this information, but I just cannot find it?

Magnus


C8, Losmandy G11, Canon 1000D astromodified.

Please Log in or Create an account to join the conversation.

1 year 4 months ago
Copello
Senior Boarder
Senior Boarder
Posts: 63
Karma: 1
More
Tempereature in DSLR subs? #33568
Hi Magnus,

the (sensor) temperature is embedded in the raw DSLR format. Try e.g.
>exiftool IMG_8327.CR2 | grep Tem
Camera Temperature              : 28 C
Color Temperature               : 5200
Color Temp As Shot              : 5200
Color Temp Auto                 : 5200
Color Temp Measured             : 5200
Color Temp Daylight             : 5200
Color Temp Shade                : 7000
Color Temp Cloudy               : 6000
Color Temp Tungsten             : 3200
Color Temp Fluorescent          : 3720
Color Temp Kelvin               : 5200
Color Temp Flash                : 6277

The gphoto2 driver uses LibRaw to unpack the raw DSLR and uses exactly these EXIF information to read out the temperatures:
if (lib_raw.imgdata.other.SensorTemperature > -273.15f)
                gphoto->last_sensor_temp = lib_raw.imgdata.other.SensorTemperature;
            else if (lib_raw.imgdata.other.CameraTemperature > -273.15f)
                gphoto->last_sensor_temp = lib_raw.imgdata.other.CameraTemperature;
The following user(s) said Thank You mlarsson

Please Log in or Create an account to join the conversation.

1 year 4 months ago
mlarsson
Platinum Boarder
Platinum Boarder
Posts: 402
Karma: 1
More
Topic Author
Tempereature in DSLR subs? #33569
Ah, wow, great!! Thanks!

Magnus


C8, Losmandy G11, Canon 1000D astromodified.

Please Log in or Create an account to join the conversation.

Time to create page: 0.432 seconds