Gradiente? Rumore? … Non capisco..

E' estate (almeno lo e' in Italia) quindi scala il raffreddamento a non piu' di zero gradi centrigradi. La ASI294MC e' notoria per essere scarsa a tenuta d'aria. Alte temperature signficano piu' umidita' nell'aria e di consequenza nella camera del sensore che non e' sigillata. Cambiare le pasticche e' totalmente inutile.

Hi Niels,

Thanks for the words of praise, surely undeserved ;)

I got both the 294MC and 294MM and both can't operate at -10degC when is warm (> 20 degC) outside or has been hot during the day. The 294MC is much older than the MM and thus more sensitive to these conditions and cooling down even in 20 minutes does not help and in the end I won't risk it. The MM is slightly better in these regards but still, wet and warm won't suit it that much. It takes less to get rid of them ice crystals once formed with the MM, possibly within half an hour whilst the older camera might take a lot longer. Bottom line: at any RH greater than 65-70% just pull the cooling up to around zero or even slightly above if really humid.

Andrea

Con poche parole mi avete aiutato molto a capire.. Grazie mille 🙂👍🏼

andrea tasselli:
surely undeserved

By sharing your experience, it is most surely deserved! Sharing knowledge gets everyone further! 

I didn't really pay much attention to the ice crystals forming until you mentioned these are actually ice.  Now I can easily spot it in the histogram as well, with a should appearing broadening the main peak. I typically just try a few images at the start of the night when it is cool to see if ice forms and then go from there. But it is interesting to actually track the RH - I will to find a humidit-o-meter (or whatever it is called ). 

But if one can shoot at -10C with the 294MC, do you see any benefit at all?

*Just slightly less hot pixels but hardly an inconvenience. Not if you have a well-honed processing pipeline.

patrice_so:
Hi, 

Is used a 294mc pro during almost 3 years, always cooling to -10° in summer and -20° in winter. Cooling time never exceeded 5 minutes. After two years, I started getting ice forming on the sensor, just as you do. It was time to change or refresh the desicant tabs in the sensor chamber. I opted for refreshing them in the microwave oven. Everything back to normal since that. 

CS 

Patrice

Interessante.. grazie.. ma la mia 294 ha solo un anno..

Hi guys! I had the same problem with my 294mc pro. It's frosting. It happens when you cool your camera too fast. Take more time to cool it down, then take a new test image.