Camera parameters

• Name: Apogee Alta U9
• Gain: 1.5 electron/ADU
• read noise: 30 electrons
• dark current: 0.1 electron/pixel/sec
• linearity limit: 35000 ADU
• Pixel size: 9 micron
• Number of pixels: 2048 x 3073
• Filters: BVRcIc

Reduction settings

All images

• Do not use the overscan
• Trim to all of first axis, 3073 on second axis

Reducing bias images

• Only need to trim

Combining bias

• Choose sigma clipping, upper and lower bounds of 5.
• Combine using mean/average

Reducing darks

IF THE DARK EXPOSURE TIME DOESN'T MATCH ANY OF THE OTHER IMAGES:

• Trim
• Subtract bias

IF THERE ARE DARK EXPOSURES THAT MATCH EVERY EXPOSURE IN THE SET:

• Trim, but do NOT subtract bias

Combining darks

• Choose sigma clipping, upper and lower bounds of 5.
• Combine using mean/average
• Group by exposure time

Reducing flats

• Trim
• Subtract bias (maybe)
• Subtract dark
  • Do not Scale by exposure time

Combining flats

• Choose sigma clipping, upper and lower bounds of 5.
• Combine using mean/average first, BUT if there are stars in the combined darks then use median instead.
• Scale before combining
  • by median
• Group by filter

Reducing science (light) images

• Trim
• Subtract bias (maybe)
• Subtract dark
  • Do not Scale by exposure time
• Flat correct