4 ms·

Silly question but how does a 4m aperture focused onto a smaller area not concentrate the heat and melt the instruments?

• esikich 2mo ago
  It's highly filtered, you are only getting a small slice of all of the wavelengths. Only a tiny fraction of all that energy hits the photo collector. I believe the collector is also actively cooled, but I might be wrong there.
  • mturmon 2mo ago
    Yes, just 0.5nm of spectrum in the instrument used (https://dkist.virtualsolar.org/vanNoortfastcam/ https://dkist.virtualsolar.org/vanNoortfastcam/, see under “DataSetDescriptions.pdf”). If the pixels really are 20x20km, located at 1AU, I get 500k photons (within that bandpass) per pixel per frame at 740 Hz, not counting optical losses. Space solar instruments like HMI on SDO (https://science.nasa.gov/mission/sdo/ https://science.nasa.gov/mission/sdo/) have one or more pre-filters in front of the instrument to block some light far from the passband and keep heating under control. I’m not sure if DKIST has such filters.
    • left-struck 2mo ago
      740hz is the frame rate you’re capturing at?
      • mturmon 2mo ago
        Not “me,” but yes, that’s the rate quoted in the document I linked about the instrument that captured the images in OP.