# Listing of Ancillary Data for Viking Images of the "Face on Mars"

## Key to Label Information

VO75
  Viking Orbiter Mission 1975

PICNO
  Picture Number XXXMYY, where
  XXX = orbit number
  M = spacecraft (VO 1 = A, VO 2 = B)
  YY = sequential number of image during orbit

FILTER
  Color filter through which image was acquired
  4 = Clear, 6 = Red, 3 = violet, 2 = minus blue

EXP
  Exposure time in milliseconds

FGD
  "Flags" for light flooding on/off, gain on/off, and off-set on/off (1 = on, 0 = off)

FSC
  Flight Sequence Computer time - unique spacecraft counter for each event time, equivalent to image ID

OET-GMT
  Original Event Time in Greenwich Mean Time, YY DOY HH MM SS

TPER
  Time from Periapsis (if available)

RNG
  Range (slant) from spacecraft to planet at intersection of optic axis

HFOV
  Horizontal Field of View in km (if available)

VFOV
  Vertical Field of View in km (if available)

SCL
  Scale of one pixel at center of image

NOR AZ
  Azimuth of (direction to) North, measured clockwise from zero line defined by a horizontal line drawn from the center of the image perpendicular to the right edge

SUN AZ
  Azimuth of (direction to) Sun, measured clockwise from zero line defined by a horizontal line drawn from the center of the image perpendicular to the right edge

S/C AZ
  Azimuth of (direction to) North, measured clockwise from zero line defined by a horizontal line drawn from the center of the image perpendicular to the right edge

INA
  Incidence angle, angle between surface normal and direction to sun, measured at the center of the image

EMA
  Emission angle, angle between surface normal and direction to spacecraft, measured at the center of the image

PHA
  Phase angle, angle between the incidence vector and the emission vector, meassured in the plane defined by these two vectors

SUNS LS
  Longitude of the sun, a measure of seasons, (where available)
  LS = 0 at beginning of northern spring (vernal equinox)
  LS = 90 at beginning of northern summer (summer solstice)
  LS = 180 at beginning of northern fall (autumnal equinox)
  LS = 270 at beginning of northern winter (winter solstice)

EDR
  Experiment Data Record, Tape and file ID

LAT C, UL, UR, LL, LR
  Latitude of the center, and upper left, upper right, lower left, and lower right corners of the image (sometimes called points 5, 1, 3, 7, and 9, respectively)

LONG C, UL, UR, LL, LR
  Longitude of the center, and upper left, upper right, lower left, and lower right corners of the image (sometimes called points 5, 1, 3, 7, and 9, respectively)

## 035A72

    VO75 1B PICNO= 035A72
    FILTER 4 (CLEAR) EXP 34 MSEC FGD 111
    FSC 26588045 OET-GMT 76 207 15 25 14 TPER +00 12 05
    RNG= 5239 KM HFOV= 55 KM VFOV= 50 KM SCL= 46 M/PXL
    NOR AZ 154 DG SUN AZ 88 DG S/C AZ 323 DG INA 79 DG EMA 10 DG
    PHA 86 DG SUNS LS= 99.2 DG EDR= CN1244 01 MAX-D=
    LAT C= +40.90 UL= +41.14 UR= +40.28 LL= +41.52 LR= +40.65
    LONG C= 9.52 UL= 8.76 UR= 9.28 LL= 9.77 LR= 10.28

## 070A13

    VO75 1A PICNO= 070A13
    FILTER 4 (CLEAR) EXP 17 MSEC FGD 111
    FSC 27280098 OET-GMT 76 243 12 38 33 TPER +00 09 05
    RNG= 5085 KM HFOV= 51 KM VFOV= 47 KM SCL= 43 M/PXL
    NOR AZ 170 DG SUN AZ 86 DG S/C AZ 310 DG INA 62 DG EMA 12 DG
    PHA 71 DG SUNS LS= 115.6 DG EDR= CN1475 06 MAX-D=
    LAT C= +40.60 UL= +40.96 UR= +40.10 LL= +41.11 LR= +40.25
    LONG C= 9.24 UL= 8.64 UR= 8.82 LL= 9.67 LR= 9.84

## 561A25

    VO75 1A PICNO= 561A25
    FILTER 6 (RED ) EXP 102 MSEC FGD 111
    FSC 36673922 OET-GMT 77 364 14 44 20 TPER -00 55 09
    RNG= 9372 KM HFOV= 193 KM VFOV= 199 KM SCL= 158 M/PXL
    NOR AZ 169 DG SUN AZ 87 DG S/C AZ 68 DG INA 76 DG EMA 32 DG
    PHA 45 DG SUNS LS= 26.6 DG EDR= CN2592 05 MAX-D=
    LAT C= +41.94 UL= +43.39 UR= +40.17 LL= +43.67 LR= +40.47
    LONG C= 8.57 UL= 5.77 UR= 6.75 LL= 10.40 LR= 11.10

## 753A34

    VO75 1B PICNO= 753A34
    FILTER 3 (VIOLT) EXP 136 MSEC FGD 111
    FSC 40372489 OET-GMT 77 192 14 01 02
    RNG=12687 KM SCL= 233 M/PXL
    NOR AZ 339 DG SUN AZ 93 DG S/C AZ 103 INA 35 DG EMA 10 DG
    PHA 2 DG  EDR= CN3300 12 MAX-D=
    LAT C= +43.25 UL= 40.1 UR= 45.6 LL= 40.1 LR= 43.9
    LONG C= 9.37 UL= 12.0 UR= 13.8 LL= 7.9 LR= 5.8

## 673B56

    VO75 2B PICNO=  673B56
    FILTER 2 (MINUS-B) EXP 68 MSEC FGD 101
    FSC 59668925 OET-GMT 78 173 05 26 00
    RNG= 11777 KM SCL= 214 M/PXL
    NOR AZ 189 DG SUN AZ 95 DG S/C AZ 206 DG INA 68 DG EMA 21 DG
    PHA 7 DG EDR= CN3300 12 MAX-D=
    LAT C= +41.76 UL= +43.73 UR= +39.27 LL= +44.14 LR= +39.62
    LONG C= 7.64 UL= 4.52 UR= 5.54 LL= 9.91 LR= 10.66

##### Calvin J. Hamilton