M81, M82

SIMPLE = T / file does conform to FITS standard

BITPIX = -32 / number of bits per data pixel

NAXIS = 3 / number of data axes

NAXIS1 = 1703 / length of data axis 1

NAXIS2 = 933 / length of data axis 2

NAXIS3 = 3 / length of data axis 3

EXTEND = T / FITS dataset may contain extensions

COMMENT FITS (Flexible Image Transport System) format is defined in 'Astronomy

COMMENT and Astrophysics', volume 376, page 359; bibcode: 2001A&A...376..359H

BZERO = 0. / Offset data range to that of unsigned short

BSCALE = 1. / Default scaling factor

PROGRAM = 'Siril 1.3.6' / Software that created this HDU

DATE = '2025-04-21T19:10:18' / UTC date that FITS file was created

DATE-OBS= '2025-04-05T19:52:41.503445' / YYYY-MM-DDThh🇲🇲ss observation start,

IMAGETYP= 'Light ' / Type of image

EXPTIME = 10. / [s] Exposure time duration

TELESCOP= 'S50_9cd25a53' / Telescope used to acquire this image

FILTER = 'IRCUT_Starless' / Active filter name

APERTURE= 5. / Aperture of the instrument

FOCALLEN= 252.327 / [mm] Focal length

XBINNING= 1 / Camera binning mode

YBINNING= 1 / Camera binning mode

XPIXSZ = 2.90000009536743 / [um] Pixel X axis size

YPIXSZ = 2.90000009536743 / [um] Pixel Y axis size

INSTRUME= 'Seestar S50' / Instrument name

CCD-TEMP= 20.125 / [degC] CCD temperature

GAIN = 80 / Sensor gain

FOCPOS = 1708 / [step] Focuser position

STACKCNT= 1673 / Stack frames

LIVETIME= 16730. / [s] Exposure time after deadtime correction

EXPSTART= 2460771.32825814 / [JD] Exposure start time (standard Julian date)

EXPEND = 2460771.59141819 / [JD] Exposure end time (standard Julian date)

OBJECT = 'M 81 '

Done