Antenna operations

Besides the overall telescope setup previously described, individual commands are available to change the antenna mount status and manage its steering/pointing:

> antennaReset

resets the antenna status after a failure, for example after the emergency stop button is released

> antennaUnstow

it only performs the unstow procedure

> antennaSetup=[code]

code: PRIM or SEC

it unstows the antenna (if it is stowed) then it sets the pointing model and the minor servo system according to the selected receiver. Mount is set to ProgramTrack mode

> servoSetup=[code]

code: CCC (MMC, KKC, QQC)

it sets the minor servo system only, without affecting other systems

> antennaTrack

it sets the mount to ProgramTrack mode, allowing the execution of sidereal tracking, on-off, OTF scans, etc. Even beam-parking acquisitions (i.e. on a fixed Az-El position) can be now performed in ProgramTrack mode by means of the goTo command

> goTo=[Az]d,[El]d

it points the antenna to fixed Az-El positions, yet the mount remains in ProgramTrack mode

e.g. > goTo=180d,45d

> track=[sourcename]

if the antenna is in ProgramTrack mode and the sourcename is known within the station catalogue (which includes the most commonly observed calibrators), it directly points to the source and tracks it

e.g. > track=3c286

> sidereal=[sourcename],[RA],[Dec],[epoch],[sector]

if the antenna mode is ProgramTrack, it points to the supplied RA-Dec position and temporarily assigns the sourcename label to it. Epoch can be 1950, 2000 or -1, the last one meaning that the provided coordinates are precessed to the observing epoch. The sector keyword forces the cable wrap sector, if needed: its value can be CW, CCW or neutral. The last option means the system will automatically choose the optimal alternative

e.g. > sidereal=src12,319.256d,70.864d,2000,neutral

Note

COORDINATE FORMATS Whenever celestial coordinates (Equatorial, Horizontal or Galactic) are specified, the allowed formats are:

  • decimal degrees, using a d suffix, for any coordinate → e.g. 30.00d
  • sexagesimal degrees, with no suffix, for any coordinate → 30:00:00
  • hh:mm:ss, with a h suffix, for longitudes only → 02:00:00h (not accepted for offsets)

Back to the commands:

> goOff=[frame],[beams]

it slews the antenna to an offset position, wrt a previously commanded target, along the longitude axis of the indicated coordinate frame (EQ, HOR or GAL). The user provides the offset value expressed in beamsizes. If the frame is HOR and target lies beyond the Elevation cutoff limits, the offset is applied in Elevation.

e.g. > goOff=HOR,5

> azelOffsets=[azoff]d,[eloff]d

it sets user-defined offsets in the Horizontal frame (degrees only). The following example sets an azimuth offset to 0.5 degrees and the elevation offset to 0.3 degrees

e.g. > azelOffsets=0.5d,0.3d

> radecOffsets=[raoff]d,[decoff]d

it sets user-defined offsets in the Equatorial frame (degrees only). The following example sets the right ascension offset to 0.3 degrees and the elevation offset to 0.0 degrees

e.g. > radecOffsets=0.3d,0.0d

> lonlatOffsets=[lonoff]d,[latoff]d

it sets user-defined offsets in the Galactic frame (degrees only). The following example sets the galactic longitude offset to 0.1 degrees and the galactic latitude offset to 0.5 degrees

e.g. > lonlatOffsets=0.1d,0.5d

Note

OFFSETS: the above user-defined offsets are the overall antenna offsets and they are mutually exclusive! If the user commands the offsets several times in a row (in one or different frames) only the last one will be effective. Offsets specified within schedules, at subscan level, sum up to these user-defined offsets if they match in reference frame. If there is a frame mismatch, the system offsets are automatically rejected (bug under fixing)

On with the list:

> antennaStop

it stops the antenna motion, if any, and changes the mount mode to “Stop”

> antennaPark

it stows the antenna

> asPark

it parks the active surface in the reference position

> servoPark

it stows the minor servo system (notice: after antennaPark, always give this command)