SPA Headers

This section describes in alphabetical order the headers associated with SPA scans.

airm -

mean number of airmasses during observation (units=.01)

atten(2) -

atmospheric attenuation in 1 airmass (unit=0.001)

azlev -

az pointing correction from levels (units=.0001 deg)

azoff -

az offset from pointing correction thumbwheel (0.0001)

azsb -

subreflector azimuth angle

azs -

azimuth at start of observation

bcen -

galactic latitude of center of map

bw(4) -

bandwidth(mhz) of the four backends

b -

galactic latitude of reference pixel

calcon -

calibration constant ( degress k / volts )

calscan -

scan number of data used for calibration of y values

cfac -

sky dip calibration factor

dalp -

right ascension displacement in arcminutes

db -

galactic latitude displacement from bcen (degrees)

dchdin -

change in channel with index in row

ddec -

declination displacement from deco (units=1arcminute)

deccen -

dec of center of map

dece -

declination at epoch of reference pixel

decoff(2) -

offsets to offsource positions (units=1 min)

dewang -

array commanded dewar angle

dewcur -

array current dewar angle

dewinv -

array dewar invert flag

dewmode -

array dewar tracking mode

dfrdin -

change in frequency with index in row (GHz)

dfside -

frequency spacing between upper and lower sideband

distance -

equatorial coordinate distance on sky from racen,deccen (units=arcmin).

dl -

galactic longitude displacement from lcen (degrees)

dra -

right ascension displacement from rao (units=4sec)

dskydin -

change in sky coordinate with index in row

dveldin -

change in velocity with index in row

dx(32) -

x offset of array pixel from center of map in map coordinate system

dy(32) -

y offset of array pixel from center of map in map coordinate system

ellev -

el pointing correction from levels (units=.0001 deg)

eloff -

el offset from pointing correction thumbwheel (0.0001)

elsb -

subreflector elevation position

els -

elevation at start of observation

epoch -

year to which coordinates are precessed

etab(2) -

fraction of beam including sidelobes which falls in 1/2 degree disk on sky (unit=0.001)

fl -

rest frequency of line (GHz)

focus -

subreflector focus position

fr1 -

sky frequency in center of first reference band (GHz)

fr2 -

sky frequency in center of 2nd reference band (GHz)

fsrate -

fraction of observing time spent on the signal freq unit=0.001

fs -

sky frequency in center of signal band (GHz)

gain(16) -

relative gains of the 16 quarry elements

h2o -

partial pressure of water in .01 mm

harm -

number of harmonic

horn(32) -

quarry id numbers for 32 pixels of scan

ichbe(4) -

index in row where data for each possible spectrometer starts

in1 -

index in row where data starts

iscold -

original scan number of data ( used in sequence funct

isideb -

dsb/ssb calibration flag

kbe -

backend identifier of data in y array (if kbe = 1 to 4 only one backend is in y, if kbe=5 all backends)

khm -

lo above(=2,+lock) or below(=1,-lock) the phase lock

khorn -

reference pixel

klo -

local oscillator above (1=lsb) or below (2=usb) line

krecv -

identifier for receiver

ksr -

signal or reference band assumed for xin1 and dxdin ( 1=signal, 2=first reference, 3=2nd reference )

ktel -

identifier for telescope (1=fcrao, 2=kitt peak, 3=texas, 4=bonn, 5=haystack, 6=nrao, 7=areceibo)

kx -

nature of x coordinate xind1 and dxdind 0=channel, 1=vlsr, 2=vsun, 3=flsr, 4=fsky, 5=ra, 6=dec, 7=az, 8=el, 9=k )

ky -

nature of y coordinate ( 0=t, 1=t*, 2=tb, 3=tau, 4=column density, 5=s, 6=weight, 7=acf )

lcen -

galactic longitude of center of map

lenscan -

length of scan as recorded in directory lenscan = 1000 * nhd + ndt, where nhd and ndt are the number of 1024 byte records in the header and data areas respectively

l -

galactic longitude of reference pixel

mapsys -

map coordinate system and grid sample spacing 1st-digit: (1=az/el, 2=ra/dec, 3=l/b) 2nd-digit: (1=bw, 1=offset bw, 2= 1/2 bw, 3= hex, {4= 1/3 bw, 5= 1/4 bw)

message(6) -

message entered by data reducer

name(6) -

source name as entered by operator ( 12 letters )

nbe -

number of backends or number of seperate feeds in case this is a continuum observation

nchan(4) -

number of channels available for each pixel in the four possible backends or number of data points per feed

ndat -

the number of data values written on tape with this header

nhorn -

number of pixels within the scan

nin -

number of data entries ( 0 to 1024 )

nrept -

number of repetitions in the y array

nxcol -

number of columns in the array receiver

off(4) -

offsets(mhz) in sky frequency of the centers of the four backends

offscan(2) -

off source scan numbers( max of two) or y-data values which are offs if offscan <0.

oper -

telescope operator (two initials)

otype -

five digit code for type of observation 1st-digit: 0=correllator, 1=continuum, 2=filter bank, 3=filter + correllator 5=continuum series 2nd-digit: 0=observation, 1=calibration, 2=test 3rd-digit: 0=on, 1=off, 2=on-off=ps, 3=on-(off1+off2)/2=dps, 4=beam switch, 5=map, 6=five point, 7=skydip, 8=calibrate 4th-digit: 0=no load switch, 1=load switch 5th-digit: 0=no polarization switching, 1=pol sw

parang -

parallactic angle

point -

monitor of telescope drive and pointing errors

pol(4) -

feed polarization of data in the four backends (units=2e-04 radians, -1=left, -2=right circular)

polcmd(2) -

polarizer positions during polswitched observations

psrate -

position switch period (=on source time, units=0.01se

qcalcon(16) -

calibration constant for 16 quarry elements

qpol(16) -

position angle of the polarization of the 16 quarry elements in coordinate system used to track dewar angle (units=2e-04 radians, -1=left, -2=right circular)

qtint(32) -

integration time for 32 array pixels

qtsys(16,4) -

system temperatures for array pixels for

qxmax(32) -

line parameter xmax for 32 array pixels

qxmean(32) -

line parameter xmean for 32 array pixels

qxmerr(32) -

line parameter xmerr for 32 array pixels

qxsig(32) -

line parameter xsig for 32 array pixels

qxwerr(32) -

line parameter xwerr for 32 array pixels

qxwidth(32) -

line parameter xwidth for 32 array pixels

qyint(32) -

line parameter yint for 32 array pixels

qymax(32) -

line parameter ymax for 32 array pixels

qysig(32) -

rms error of array pixel

qyterr(32) -

line parameter yterr for 32 array pixels

racen -

ra of center of the map

rae -

right ascension at epoch of reference pixel

raoff(2) -

offsets to offsource positions (units=4sec of time)

resin -

x coordinate resolution in terms of indice

rgain(8) -

relative receiver gains referenced to best one

rotang -

map rotation angle

rx -

free location for mapping coordinates

scale(8) -

additional scale factors not included above (units= 0.001 )

scan -

scan number ( 500 to 30000)

smark(2) -

standard marker within the scan which contains spa rev

spill(2) -

fraction of beam directed skyward(units=0.001)

stype -

five digit code for type of spectral line observation 1st-digit: ( 0=total power, 1=frequency switching, 2=double frequency switching ) 2nd-digit: ( 0=series, 1=parallel )

tatm -

assumed atmospheric temperature used in sky dip

tcal(8) -

cal temperatures( units=0.05k )

temp(1) -

outside air temperature at beginning of scan ( unit=0.1k for all these temperatures )

temp(2,3) -

dewpoints inside and outside dome

temp(4) -

average temperature on radome

temp(5) -

average temperature on antenna surface

temp(6) -

maximum temperature on surface

temp(7) -

minimum temperature on surface

tgain(2) -

telescope gain in forward direction at center of main beam( units=0.001 )

tint -

integration time(sec)

tpave -

total power dvm reading averaged over observation

tpdev -

max percentage deviation of tp from tpave(unit=.01

ts(8) -

system temperature (units=1k)

tsid -

sidereal time at start of observation

utd -

mean universal time date

vcal(2) -

dual channel contiuum v/f calibration constants

vclsr -

velocity correction to lsr s.t. vtotal=vlsr+vclsr

vcsun -

velocity correction to heliocentric as for lsr

vlsr -

center velocity used when observation was made

xch1 -

channel number of in1

xfr1 -

frequency of in1 (GHz)

xlabel -

x-axis label (8 characters )

xmax -

channel, vleocity, or frequency(GHz) for ymax

xmean -

mean channel, velocity, or frequency(GHz) from line measuring function. In the case of a continuum mapping observation, this parameter and the ones which follow are the parameters of the gaussian fit.

xmerr -

formal error to mean channel, velocity, or frequency (GHz) from line function

xoff(16) -

x offset of the 16 quarry elements in quarry coordinates (units=1e-4 degrees)

xsigma -

sigma(width) in channel, velocity, or frequency(GHz)

xsky1 -

sky coordinate of in1 (used during mapping )

xtype -

three digit code specifying types of x coords in header variables xvel1, dvdin, xfr1, dfrdin, and xsky1, dskydin 1st-digit: ( 0=vlsr, 1=vsun ) 2nd-digit: ( 0=flsr, 1=fsky ) 3rd-digit: (0=ra, 1=dec, 2=az, 3=el, 4=none of the

xvel1 -

velocity of in1

xwerr -

formal error to xwidth from line function

xwidth -

full width in x to first crossing to y >ymax/2

yint -

integrated y values from line measuring function

ylabel -

y-axis label (8 characters )

ymax -

maximum y value from line measuring function

yoff(16) -

y offset of the 16 quarry elements in quarry coordinates (units=1e-4 degrees)

ysb -

subreflector y axis lvdt

ysigma -

rms noise in spectra measured by baseline or wave

ysky -

continuum raster map y offset

yterr -

formal error to integrated y values from line function