AutoOOF

The intent of this scan is to automatically peak and/or focus the antenna for the current location on the sky and with the current receiver, therefore it should not require any user input. However, by setting any of the optional arguments the user may partially or fully override the the calibration search and/or procedural steps as described below.

The intent of these scans are to automatically peak and/or focus the antenna for the current location on the sky and with the current receiver, therefore it should not require any user input. However, by setting any of the optional arguments the user may partially or fully override the the calibration search and/or procedural steps as described below.

The intent of the AutoOOF scan is to automatically run an Out of Focus holography scan for the current location on the sky and with the current receiver, therefore it should not require any user input. However, by setting any of the optional arguments the user may partially or fully override the the calibration search and/or procedural steps as described below.

1. Run a scan using either Peak and/or Focus.

1. Run a scan using either Peak and/or [[Observing.ScanTypes#Focus][Focus] or RALongMap.

• setting "gold" --NEED description from Frank Ghigo on the "gold" standard
• selecting a receiver, step 2 is skipped

• receiver is the name of the GBT receiver to be used. For AutoPeak?/AutoFocus/AutoPeakFocus the supported receivers are Rcvr1_2 'Rcvr_342', 'Rcvr_450', 'Rcvr_600', Rcvr_800', 'Rcvr_1070', 'Rcvr1_2', 'Rcvr4_6', 'Rcvr8_10', 'Rcvr12_18', 'Rcvr2_3', 'Rcvr18_22', 'Rcvr22_26', 'Rcvr40_52', 'Rcvr26_40', and 'NoiseSource'. For AutoOOF? the supported receivers are 'Rcvr8_10', 'Rcvr12_18', 'Rcvr18_22', 'Rcvr40_52', 'Rcvr26_40', and 'Rcvr_PAR'.

AutoFocus/AutoPeak/AutoPeakFocus(source, location, frequency, flux, radius, balance, configure, beamName)

AutoFocus/AutoPeak/AutoPeakFocus(source, location, frequency, flux, radius, balance, configure, beamName, gold)

• gold is a boolean. If True then only ``Gold standard sources'' (.i.e. sources suitable for pointing at high frequencies) will be used by AutoPeakFocus(). This parameter is ignored if the ``source'' parameter is specified. Refer to PTCS Project Note number 58 for details.

RALongMap(location, hLength, vLength, vDelta, referenceOffset, referenceInterval, scanDuration, beamName, unidirectional, start, stop)

RALongMapWithReference(location, hLength, vLength, vDelta, referenceOffset, referenceInterval, scanDuration, beamName, unidirectional, start, stop)

RALongMap?("CygA",

RALongMapWithReference?("CygA",

Peak("0137+3309", Offset("Encoder", "00:90:00", 0), Offset("Encoder, 0, "00:90:00"), 30, "1")

Peak("0137+3309", Offset("Encoder", "00:90:00", 0), Offset("Encoder", 0, "00:90:00"), 30, "1")

The following example does a subreflector nod between beams 1 and 2 for 60 seconds, each nod or half-cycle lasts for three integrations where Rcvr26_40 was selected in the configuration:

The following example does a subreflector nod between beams 1 and 2 for 60 seconds, each nod or half-cycle lasts for three integrations where Rcvr26_40 was selected in the configuration:

For two-beam receivers SubBeamNod causes the subreflector to tilt about the x axis between the two feeds at the given periodicity. The primary mirror is centered on the midpoint between the two beams. The beam selections are extracted from the scan's beamName, i.e., MR12 or MR34. The "first" beam ("1" or "3") performs the first integration. The periodicity is specified in seconds (float) per nod (half-cycle). A nod is limited to a minimum of 4.4 seconds. An example:
Slew("3C48", beamName="MR12", submotion=SubNod(4.4826624))
Alternatively, one can specify the nod time in units of the primary backend's integration times (integer) by setting the periodicity units to integrations instead of the default seconds, e.g.,
Track("3C48", None, 60.0, beamName="MR12", submotion=SubNod(nodLength=3, nodUnit="integrations"))
If the backend's actual integration time is obtainable then a warning is issued if the alignment between the integration times and the nod times shift over the duration of the scan by more than 10% of the nod time. A warning is issued in any case if the backend's actual integration time is not obtainable. Attempting to use integrations as the unit when the integration time cannot be obtained from the selected backend will cause a failure.

For two-beam receivers SubBeamNod causes the subreflector to tilt about the x axis between the two feeds at the given periodicity. The primary mirror is centered on the midpoint between the two beams. The beam selections are extracted from the scan's beamName, i.e., MR12 or MR34. The "first" beam ("1" or "3") performs the first integration. The periodicity is specified in seconds (float) per nod (half-cycle). A nod is limited to a minimum of 4.4 seconds. An example:
Track("3C48", None, 60.0, beamName="MR12", submotion=SubNod(4.4826624))
Alternatively, one can specify the nod time in units of the primary backend's integration times (integer) by setting the periodicity units to integrations instead of the default seconds, e.g.,
Track("3C48", None, 60.0, beamName="MR12", submotion=SubNod(nodLength=3, nodUnit="integrations"))
If the backend's actual integration time is obtainable then a warning is issued if the alignment between the integration times and the nod times shift over the duration of the scan by more than 10% of the nod time. A warning is issued in any case if the backend's actual integration time is not obtainable. Attempting to use integrations as the unit when the integration time cannot be obtained from the selected backend will cause a failure.

SubBeamNod

Syntax:

SubBeamNod(location, scanDuration, beamName, nodLength, nodUnit)

Parameter Info:

• location is a Catalog source name or Location object. It specifies the source upon which to do the nod.
• scanDuration is a float. It specifies the length of each subscan in seconds.
• beamName is a string. It specifies the receiver beam pair to use for nodding. beamName can be "MR12" or "MR34".
• nodLength is a number (integer for "integrations", and float or integer for "seconds".
• nodUnit is a string, either "integrations" or "seconds". The default is "seconds".

For two-beam receivers SubBeamNod causes the subreflector to tilt about the x axis between the two feeds at the given periodicity. The primary mirror is centered on the midpoint between the two beams. The beam selections are extracted from the scan's beamName, i.e., MR12 or MR34. The "first" beam ("1" or "3") performs the first integration. The periodicity is specified in seconds (float) per nod (half-cycle). A nod is limited to a minimum of 4.4 seconds. An example:
Slew("3C48", beamName="MR12", submotion=SubNod(4.4826624))
Alternatively, one can specify the nod time in units of the primary backend's integration times (integer) by setting the periodicity units to integrations instead of the default seconds, e.g.,
Track("3C48", None, 60.0, beamName="MR12", submotion=SubNod(nodLength=3, nodUnit="integrations"))
If the backend's actual integration time is obtainable then a warning is issued if the alignment between the integration times and the nod times shift over the duration of the scan by more than 10% of the nod time. A warning is issued in any case if the backend's actual integration time is not obtainable. Attempting to use integrations as the unit when the integration time cannot be obtained from the selected backend will cause a failure.

The following example does a subreflector nod between beams 1 and 2 for 60 seconds, each nod or half-cycle lasts for three integrations where Rcvr26_40 was selected in the configuration:

SubBeamNod("1011-2610", 60.0, "MR12", nodLength=3, nodUnit="integrations")

Used with these GBT Standard Observing Modes: Position Switched (Dual Beam); Beam Switched

WARNING: This procedure should be used with caution at high frequencies or in confused regions of the sky. Due to imprecisely repeatable scan-start overheads, the location of the OFF beam from one scan to the next is not guaranteed to be in a fixed place on the sky. Variations greater than an arcminute are not uncommon.

This scan type performs a "Least Squares Frequency Switch" where a single scan is broken into 8 equal parts such that each subscan has a difference frequency (as described above). This routine was devised by Tim Robishaw and Carl Heiles to minimize the IF ripples in the bandpass.

This scan type performs a "Least Squares Frequency Switch," where a single scan is broken into 8 equal parts, each observed at a unique frequency (as described above). This routine was devised by Tim Robishaw and Carl Heiles to minimize the IF ripples in the bandpass.

(the data collector and switching signal generator) is set up for an

(the data collector and switching signal generator) is set up for

• scanDuration is a float. It specifies the length of the subscans in seconds. It must be evenly divisible by 8 seconds. Each subscan (each frequency) will integrate for 1/8 of the Scan Duration.

• scanDuration is a float. It specifies the length of the scan in seconds. It must be evenly divisible by 8 seconds. The spectrometer will integrate for 1/8 of the Scan Duration on each frequency.

Note that to accomplish this ability, the spectrometer and LO1's switching signal states are defined differently, i.e., the spectrometer (the data collector and switching signal generator) is set up for an one scan with 8 equal integrations and 1 sig/ref period per integration. The LO1 (the frequency controller) is set up for an one scan, but with 8 sig/ref periods per scan. Then the delta-frequencies fed into the LO1 are doubles, i.e., f1, f1, f2, f2, f3, f3, ..., f8, f8, so each integration has two switching states which are equivalent.

-- MarkClark - 25 Jul 2006

This scan type wo

1. Get recmmended beam, antenna/subreflector motions, and duration for peak and/or focus scans.

1. Get recommended beam, antenna/subreflector motions, and duration for peak and/or focus scans.

• source is a string. It specifies the name of a particular source in the pointing catalog to be used for calibration. The default is None. Specifying a calibrator bypasses the search process. Please note that NVSS source names are used in the pointing catalog. If the name is not located in the pointing catalog then all the user-specified catalogs previously defined in the scheduling block are searched. If the name is neither in the pointing catalog nor in the user defined catalog(s) then the procedure fails.

• source is a string. It specifies the name of a particular source in the pointing catalog or a user-defined Catalog to be used for calibration. The default is None. Specifying a calibrator bypasses the search process. Please note that NVSS source names are used in the pointing catalog. If the name is not located in the pointing catalog then all the user-specified catalogs previously defined in the scheduling block are searched. If the name is neither in the pointing catalog nor in the user defined catalog(s) then the procedure fails.

SOM: Focus Peak Corrections

Used with these GBT Standard Observing Modes: Focus Peak Corrections

SOM:

Used with these GBT Standard Observing Modes:

SOM: OTF Map; Continuum Map

Used with these GBT Standard Observing Modes: OTF Map; Continuum Map

SOM: OTF Map; Continuum Map

Used with these GBT Standard Observing Modes: OTF Map; Continuum Map

SOM: Corrections

Used with these GBT Standard Observing Modes: Corrections

SOM: Z17; Spider

Used with these GBT Standard Observing Modes: Z17; Spider

SOM: Position Switched (Dual Beam); Beam Switched

Used with these GBT Standard Observing Modes: Position Switched (Dual Beam); Beam Switched

SOM: Position Switched (Single Beam)

Used with these GBT Standard Observing Modes: Position Switched (Single Beam)

SOM: Position Switched (Single Beam)

Used with these GBT Standard Observing Modes: Position Switched (Single Beam)

SOM: Position Switched (Single Beam)

Used with these GBT Standard Observing Modes: Position Switched (Single Beam)

SOM: Position Switched (Single Beam)

Used with these GBT Standard Observing Modes: Position Switched (Single Beam)

SOM: Pointing Corrections

Used with these GBT Standard Observing Modes: Pointing Corrections

SOM: Point Map

Used with these GBT Standard Observing Modes: Point Map

SOM: Point Map

Used with these GBT Standard Observing Modes: Point Map

SOM: OTF Map; Continuum Map

Used with these GBT Standard Observing Modes: OTF Map; Continuum Map

SOM: OTF Map; Continuum Map

Used with these GBT Standard Observing Modes: OTF Map; Continuum Map

SOM: LSFS; Z17

Used with these GBT Standard Observing Modes: LSFS; Z17

SOM: Tipping Scan

Used with these GBT Standard Observing Modes: Tipping Scan

SOM: Total Power Track; Frequency Switched Track; VLBI; Pulsar; Radar

Used with these GBT Standard Observing Modes: Total Power Track; Frequency Switched Track; VLBI; Pulsar; Radar

SOM: LSFS; Spider

Used with these GBT Standard Observing Modes: LSFS; Spider

-- KarenONeil - 17 May 2006

-- MarkClark - 25 Jul 2006

• scanDuration is a float. It specifies the length of each subscan in seconds.

• scanDuration specifies the length of the scan. If the resulting stop time has passed, then the scan is skipped and a message is sent to the observation log. The value is a float representing seconds.

• startTime is a time string with the following format: "hh:mm:ss". It allows the observer to specify a start time for the Track.
• stopTime is a time string with the following format: "hh:mm:ss". It allows the observer to specify a stop time for the Track.

• startTime specifies when the scan begins. If the start time is in the past then the scan starts as soon as possilble with a message sent to the scan log. If the start time plus the scan duration is in the past, then the scan is skipped with a message to the observation log. The value may be:
  • a time Note, if startTime is more than a ten minutes in the future then a message is sent to the observation log.
  • a Horizon When a Horizon object is used, the start time is implicitly computed, e.g., Track("3C247", None, 120.0, startTime=Horizon()) If the source never rises then the scan is skipped and if the source never sets then the scan is started immediately. In either case a message is sent to the observation log.
• stopTime specifies when the scan completes. If the stop time is in the past then the scan is skipped with a message to the observation log. The value may be:
  • a time
  • a Horizon When a Horizon object is used, the stop time is implicitly computed, e.g., a complete scheduling block for tracking VirgoA from rise until set and using a horizon of 20 degrees would be: Catalog("fluxcal"); horizon = Horizon(20.0); Track("VirgoA", None, startTime=horizon, stopTime=horizon) If the source never sets, then the scan stop time is set to 12 hours from the current time.

• coordMode is a string. It specifies the coordinate mode for the radius IS THIS CORRECT??

• coordMode is a string. It specifies the coordinate mode for the radius that generate the map. The default is "AzEl".

1. Get recommended beam, offset(s), and duration for peak and/or focus scans.

1. Get recmmended beam, antenna/subreflector motions, and duration for peak and/or focus scans.

• coordMode is a string. It specifies the coordinate mode for the offsets that generate the map. The default is "AzEl".

• coordMode is a string. It specifies the coordinate mode for the radius IS THIS CORRECT??

This command scans in the Dec or latitude-like direction, map columns are offset in RA

This command scans in the Dec or latitude-like direction, and steps in RA

Note that the "Location" may be in a different coordinate system than the "Offsets".

Note that the "Location" may be in a different coordinate system than the lengths.

A Declination/Latitude map with reference source, or DecLatMapWithReference, does a raster scan centered on a specific location on the sky and periodically moves to a reference location on the sky. Scaning is done in the declination, latitude, or elevation coordinate depending on the desired coordinate mode. This procedure does allows the user to periodically move to a reference offset on the sky, please see DecLatMap if no reference point is required. The starting point of the map is defined as (-hLength/2, -vLength/2).

A Declination/Latitude map with reference source, or DecLatMapWithReference, does a raster scan centered on a specific location on the sky and periodically moves to a reference location on the sky. Scaning is done in the declination, latitude, or elevation coordinate depending on the desired coordinate mode. This procedure does allows the user to periodically move to a reference position on the sky, please see DecLatMap if no reference point is required. The starting point of the map is defined as (-hLength/2, -vLength/2).

Focus(location, start, offset, scanDuration, beamName)

Focus(location, start, focusLength, scanDuration, beamName)

• offset is a float. It specifies the ending position of the subreflector relative to the starting location (also in mm). The default is the PTCS recommended value for the receiver.

• focusLength is a float. It specifies the ending position of the subreflector relative to the starting location (also in mm). The default is the PTCS recommended value for the receiver.

The Focus procedure sweeps the subreflector or prime focus (depending on the receiver in use) through the axis aligned with the beam. Its primary use is to determine focus offsets for use in subsequent scans. Note that the offset and scanDuration should be overridden as a unit since together they determine the rate.

The Focus procedure sweeps the subreflector or prime focus (depending on the receiver in use) through the axis aligned with the beam. Its primary use is to determine focus positions for use in subsequent scans. Note that the FocusLength? and scanDuration should be overridden as a unit since together they determine the rate.

OffOn(location, offset, scanDuration, beamName)

OffOn(location, referenceOffset, scanDuration, beamName)

• offset is an Offset object. It specifies the location of the Off subscan relative to the location specified by the first parameter.
• beamName is a string. It specifies the receiver beam to use for both subscans. beamName can be "C", "1", "2", "3", "4" or any valid combination for the receiver you are using such as "MR12" and "MR34". The default value for beamName is "1".

• referenceOffset is an Offset object. It specifies the location of the Off subscan relative to the location specified by the first parameter.

• beamName is a string. It specifies the receiver beam to use for both subscans. beamName can be "C", "1", "2", "3", "4" or any valid combination for the receiver you are using such as "MR12" and "MR34". The default value for beamName is "1".

The OffOn scan performs two subscans. The first subscan is at an offset to the source used in the second subscan and the second subscan is on source.

The OffOn scan performs two subscans. The first subscan is offset from the location, used in the second scan by the referenceOffset and subscan is on source.

The following example does an OffOn scan with offsets of 1 degree in width and height and a 60 second subscan duration, using beam 1:

The following example does an OffOn scan with reference offsets of 1 degree in width and height and a 60 second subscan duration, using beam 1:

OnOff(location, offset, scanDuration, beamName)

OnOff(location, referenceOffset, scanDuration, beamName)

• offset is an Offset object. It specifies the location of the Off subscan relative to the location specified by the first parameter.
• beamName is a string. It specifies the receiver beam to use for both subscans. beamName can be "C", "1", "2", "3", "4" or any valid combination for the receiver you are using such as "MR12" and "MR34". The default value for beamName is "1".

• referenceOffset is an Offset object. It specifies the location of the Off subscan relative to the location specified by the first parameter.

• beamName is a string. It specifies the receiver beam to use for both subscans. beamName can be "C", "1", "2", "3", "4" or any valid combination for the receiver you are using such as "MR12" and "MR34". The default value for beamName is "1".

The following example does an OnOff scan with offsets of 1 degree in width and height and a 60 second subscan duration, using beam 1:

The following example does an OnOff scan with reference offsets of 1 degree in width and height and a 60 second subscan duration, using beam 1:

Peak(location, hOffset, vOffset, scanDuration, beamName)

Peak(location, hLength, vLength, scanDuration, beamName)

• hOffset is an Offset object. It specifies the horizontal distance used for the Peak. The default value is the PTCS recommended value for the receiver.
• vOffset is an Offset object. It specifies the vertical distance used for the Peak. The default value is the PTCS recommended value for the receiver.

• hLength is an Offset object. It specifies the horizontal distance used for the Peak. The default value is the PTCS recommended value for the receiver.
• vLength is an Offset object. It specifies the vertical distance used for the Peak. The default value is the PTCS recommended value for the receiver.

The Peak scan type sweeps through the specified sky location in the four cardinal directions. Its primary use is to determine pointing offsets for use in subsequent scans Note that the offsets and scanDuration should be overridden as a unit since together they determine the rate.

The Peak scan type sweeps through the specified sky location in the four cardinal directions. Its primary use is to determine pointing corrections for use in subsequent scans Note that the hLength/vLength and scanDuration should be overridden as a unit since together they determine the rate.

The following example does a peak in encoder coordinates with 90 minute offsets and a 30 second subscan duration using beam 1.

The following example does a peak in encoder coordinates with 90 minute lengths and a 30 second subscan duration using beam 1.

Tip(location, offset, scanDuration, beamName, startTime, stopTime)

Tip(location, endOffset, scanDuration, beamName, startTime, stopTime)

• offset is an Offset object. It specifies the beams final position for the scan, relative to the location specified in the first parameter.

• endOffset is an Offset object. It specifies the beams final position for the scan, relative to the location specified in the first parameter.

Track(location, offset, scanDuration, beamName, startTime, stopTime)

Track(location, endOffset, scanDuration, beamName, startTime, stopTime)

• offset is an Offset object. It moves the beam to an optional offset position that is specified relative to the location specified in the first parameter. If no offset is desired, use None for this parameter.

• endOffset is an Offset object. It moves the beam to an new position during the scans which is specified relative to the location specified in the first parameter. If no offset is desired, use None for this parameter.

-- KarenONeil - 17 May 2006

• offset is an Offset object. It moves the beam to an offset position that is specified relative to the location specified in the first parameter.

• offset is an Offset object. It specifies the beams final position for the scan, relative to the location specified in the first parameter.

• offsetCoordmode is a string. It specifies the coordinate mode for the offsets that generate the map. The default is "AzEl".

• coordMode is a string. It specifies the coordinate mode for the offsets that generate the map. The default is "AzEl".

• scanDuration is a float. It specifies the length of each subscan in seconds. Default is None.

• scanDuration is a float. It specifies the length of each subscan in seconds.

• scanDuration is a float. It specifies the length of each subscan in seconds. Default is None.

• scanDuration is a float. It specifies the length of each subscan in seconds.

• scanDuration is a float. It specifies the length of each subscan in seconds. Default is None.

• scanDuration is a float. It specifies the length of each subscan in seconds.

• scanDuration is a float. It specifies the length of each subscan in seconds. Default is None.

• scanDuration is a float. It specifies the length of each subscan in seconds.

• scanDuration is a float. It specifies the length of each subscan in seconds. Default is None.

• scanDuration is a float. It specifies the length of each subscan in seconds.

• scanDuration is a float. It specifies the length of each subscan in seconds. Default is None.

• scanDuration is a float. It specifies the length of each subscan in seconds.

Slew(location, beamName)

Slew(location, offset, beamName)

• location is a Catalog source name or Location object. It specifies the source to which the telescope should slew.
• beamName is a string. It specifies the receiver beam to use for the scan. beamName can be "C", "1", "2", "3", "4" or any valid combination for the receiver you are using such as "MR12" and "MR34". The default value for beamName is "1".

• location is a Catalog source name or Location object. It specifies the source to which the telescope should slew. The default is the current location in "J2000" coordinate mode.
• offset is an Offset object. It moves the beam to an optional offset position that is specified relative to the location specified in the first parameter. The default is None.
• beamName is a string. It specifies the receiver beam to use for the scan. beamName can be "C", "1", "2", "3", "4" or any valid combination for the receiver you are using such as "MR12" and "MR34". The default is "1".

Slew moves the telescope to point to a specified location on the sky. If you would like to Slew to an offset from a location on the sky, simply add a Location to an Offset, e.g. Slew(Location("J2000", "01:37:41.30", "+33:09:35.4") + Offset("J2000", 2.0, 0.0)) or you can do the addition outside of Slew by writing something like position = Location("J2000", "01:37:41.30", "+33:09:35.4") + Offset("J2000", 2.0, 0.0) and then Slew(position). Or with a catalog position = catalog['3C48']['location'] + Offset("J2000", 2.0, 0.0).

Slew moves the telescope beam to point to a specified location on the sky.

1. If only a location is given the antenna slews to the indicated position.
2. If a location and offset are given, the antenna slews to the indicated position plus the specified offset.
3. If only an offset is given, the antenna slews to the current location plus the specified offset.

Slew("3C48", "C")

Catalog("fluxcal")

Slew("3C48", beamName="C")

Note that Slew() with no arguments is basically a NOP, i.e., it slews to the current location (but in J2000):

Slew()    # ??

Though one could change beams at that position:

Slew(beamName="2")

-->

-->

Scan timing must be specified by either a scanDuration, a stopTime, or a startTime plus scanDuration.

Scan timing must be specified by either a scanDuration, a stopTime, a startTime plus stopTime, or a startTime plus scanDuration.

Scan timing must be specified by either a scanDuration, a stopTime, or a startTime plus scanDuration.

Scan timing must be specified by either a scanDuration, a stopTime, a startTime plus stopTime, or a startTime plus scanDuration.

Brian, need meatier description here.

The area of the sky covered will be circular, with a diameter equal to twice the specified map_radius. For map radii of a few arcminutes, a radial_osc_period of 60 sec or longer is recommended; a scanDuration of 20 radial_osc_period's will result in an approximately closed pattern. For beamsizes of 20 arcsec (fwhm) or so, the circular area mappped will be fully sampled if the map radius is less than 6'. It is not an especially useful observing mode for general-purpose single-beam mapping, since the largest "hole" in the map is approximately 0.3 x map_radius. However it is useful for focal-plane arrays.

Daisy("3C123", 5, 30, 0, 0, 150)

Daisy(location="3C123", map_radius=5, radial_osc_period=60, radial_phase=0, rotation_phase=0, scanDuration=1200)

This scan type is used for polarization studies, but could be used for other observing schemes,

This scan type wo

This scan type is used for polarization studies, but could be used for other observing schemes. It only works with the Spectrometer backend.

Tip(location, offset, scanDuration, beamName)

Tip(location, offset, scanDuration, beamName, startTime, stopTime)

• startTime is a time string with the following format: "hh:mm:ss". It allows the observer to specify a start time for the Tip.
• stopTime is a time string with the following format: "hh:mm:ss". It allows the observer to specify a stop time for the Tip.

Scan timing must be specified by either a scanDuration, a stopTime, or a startTime plus scanDuration.

Scan timing must be specified by either a scanDuration, a stopTime, or a startTime plus scanDuration.

This scan type performs a "Least Squares Frequency Switch" where a single scan is broken into 8 equal parts such that each subscan has a difference frquency (as described above). This routine was devised by Tim Robishaw and Carl Heiles to minimize the IF ripples in the bandpass.

This scan type performs a "Least Squares Frequency Switch" where a single scan is broken into 8 equal parts such that each subscan has a difference frequency (as described above). This routine was devised by Tim Robishaw and Carl Heiles to minimize the IF ripples in the bandpass.

• deltaf is a float. It specifies the change in frequency in MHz which ...
• scanDuration is a float. It specifies the length of the subscans in seconds. It must be evenly divisible by 8 seconds.

• deltaf is a float. It specifies the change in frequency in MHz which sets the multiplicative factor for the frequency offset. That is, the frequency offsets are equal to [0.0, 8.5, 3.5, 1.5, -4.5, -7.5, -8.5, -22.5]*deltaf
• scanDuration is a float. It specifies the length of the subscans in seconds. It must be evenly divisible by 8 seconds. Each subscan (each frequency) will integrate for 1/8 of the Scan Duration.

This scan type performs a "Least Squares Frequency Switch" where a single subscan is broken into 8 equal parts such that

This scan type performs a "Least Squares Frequency Switch" where a single scan is broken into 8 equal parts such that each subscan has a difference frquency (as described above). This routine was devised by Tim Robishaw and Carl Heiles to minimize the IF ripples in the bandpass.

This scan type is used for polarization studies.

This scan type is used for polarization studies, but could be used for other observing schemes,

The following example generates a subscan at 1258+6126:

The following example generates a subscan at 1258+6126 ...

LSFS("1258+6126", 12.5/512.0, 80.0)

LSFS("1258+6126",0.0244,80)

• offset is an Offset object. It specifies the length of the subscans and the angle from location of the initial subscan.

• offset is an Offset object. It specifies the 1/2 length of the subscans and the angle from location of the initial subscan. That is, if you were to use offset = Offset("AzEl", "00:40:00","00:00:00",cosv=True) then the first leg of the scan would start at +40minutes in azimuth (from the location) and would complete at -40minutes in AZ. If instead you used offset = Offset("AzEl", "00:40:00","00:40:00",cosv=True) the first leg would start at AZ=+40min, EL=+40 minutes, and would go to the opposite (AZ=-40min, EL=-40min)

• slices is an integer. It specifies the number of cross subscans through location. The default is 4 (making a spider shape).

• slices is an integer. It specifies the number of subscans through location. The default is 4 (making a spider shape).

• cals is a string. It specifies the order of calibration subscans, i.e., at the beginning of the scan ("begin"), at the end of the scan ("end"), or both ("both"). The default is "both".

• cals is a string. It specifies the order of calibration subscans, i.e., at the beginning of the slice subscan ("begin"), at the end of the slice subscan ("end"), or both ("both"). The default is "both".

Spider executes the specified number of symmetrical slices or cross subscans of length scanDuration through the specified location. Each slice is of length 2*offset. The argument offset also specifies the angle of the initial slice. The user may specify unidirectional or bidirectional subscans of length calDuration and when to run calibration subscans relative to each slice, i.e., at "begin", "end", or "both".

Spider executes the specified number of slices of length scanDuration through the specified location. Each slice is of length 2*offset. The argument offset also specifies the angle of the initial slice. The user may specify unidirectional or bidirectional subscans of length calDuration and when to run calibration subscans relative to each slice, i.e., at "begin", "end", or "both".

• offset is an Offset object. It specifies the angle from location of the initial subscan.

• offset is an Offset object. It specifies the angle from location of the initial subscan as well as the radius of the inner circle.

Z17 executes two circles of point subscans around location at 45 degree intervals. The first circle with a radius of offset and the second circle at a radius of sqrt(2)*offset. The initial subscan is at the angle specified by the offset. After circling twice, the procedure executes a subscan on location. The entire set of 17 subscans each of length scanDuration, is sandwiched between two cal subscans of lengths calDuration which consist of equal parts calibration noise signal on and off.

Z17 executes two circles of point subscans around location at 45 degree intervals. The first circle with a radius of offset and the second circle at a radius of sqrt(2)*offset. The initial subscan is at the angle specified by the offset. After circling twice, the procedure executes a subscan on location. The entire set of 17 subscans each of length scanDuration, is sandwiched between two cal subscans of lengths calDuration which consist of equal parts calibration noise signal on and off.

Daisy

Daisy(location, map_radius, radial_osc_period, radial_phase, rotation_phase, scanDuration, beamName, cos_v, coordMode, calc_dt)

Parameter Info:

• location is a Catalog source name or Location object. It specifies the center of the map.
• map_radius is a float which specifies the radius of the map's leaves in arcmins.
• radial_osc_period is a float which specifies the period of the radial oscillation in seconds.
• radial_phase is a float which specifies the radial phase in radians.
• rotation_phase is a float which spcecifies the rotational phase in radians.
• scanDuration is a float. It specifies the length of the subscan in seconds.
• beamName is a string. It specifies the receiver beam to use for both subscans. beamName can be "C", "1", "2", "3", "4" or any valid combination for the receiver you are using such as "MR12" and "MR34". The default value for beamName is "1".
• cos_v is a boolean. It specifies whether secan minor corrections should be used. The default is True.
• offsetCoordmode is a string. It specifies the coordinate mode for the offsets that generate the map. The default is "AzEl".
• calc_dt is a float. It specifies time sampling, should be between .1 and .5. The default is .1.

Brian, need meatier description here.

This example produces a three leaf map about "3C123":

Catalog("fluxcal")
Daisy("3C123", 5, 30, 0, 0, 150)

SOM:

• slices is an integer. It specifies the number of cross subscans through location. The default is 2 (like a peak scan).

• slices is an integer. It specifies the number of cross subscans through location. The default is 4 (making a spider shape).

This scan type performs a "Least Squares Frequency Switch" where a single subscan is broken into 8 equal parts such that

LSFS

LSFS(location, deltaf, scanDuration, beamName)

Parameter Info:

• location is a Catalog source name or Location object. It specifies the source which is to be tracked.
• deltaf is a float. It specifies the change in frequency in MHz which ...
• scanDuration is a float. It specifies the length of the subscans in seconds. It must be evenly divisible by 8 seconds.
• beamName is a string. It specifies the receiver beam to use for the scan. beamName can be "C", "1", "2", "3", "4" or any valid combination for the receiver you are using such as "MR12" and "MR34". The default value for beamName is "1".

This scan type is used for polarization studies.

The following example generates a subscan at 1258+6126 ...

Catalog()

LSFS("1258+6126", 12.5/512.0, 80.0)

SOM: Z17; Spider

Spider

Spider(location, offset, scanDuration, slices, beamName, unidirectional, cals, calDuration)

Parameter Info:

• location is a Catalog source name or Location object. It specifies the source which is to be tracked.
• offset is an Offset object. It specifies the length of the subscans and the angle from location of the initial subscan.
• scanDuration is a float. It specifies the length of the subscans in seconds.
• slices is an integer. It specifies the number of cross subscans through location. The default is 2 (like a peak scan).
• beamName is a string. It specifies the receiver beam to use for the scan. beamName can be "C", "1", "2", "3", "4" or any valid combination for the receiver you are using such as "MR12" and "MR34". The default value for beamName is "1".
• unidirectional is a Boolean. It specifies whether each slice is scanned once in one direction or twice in both directions. The default is True (one direction).
• cals is a string. It specifies the order of calibration subscans, i.e., at the beginning of the scan ("begin"), at the end of the scan ("end"), or both ("both"). The default is "both".
• calDuration is a float. It specifies the length of the calibration subscans in seconds. The default is 10.0.

Spider executes the specified number of symmetrical slices or cross subscans of length scanDuration through the specified location. Each slice is of length 2*offset. The argument offset also specifies the angle of the initial slice. The user may specify unidirectional or bidirectional subscans of length calDuration and when to run calibration subscans relative to each slice, i.e., at "begin", "end", or "both".

This scan type is used for polarization studies.

The following example generates subscans through 1258+6126 starting the first leg 40' from the source's "right."

Catalog()

Spider("1258+6126", Offset("AzEl", "00:40:00", "00:00:00"), 30.0)

SOM: LSFS; Z17

Z17

Z17(location, offset, scanDuration, beamName, calDuration)

Parameter Info:

• location is a Catalog source name or Location object. It specifies the source which is to be tracked.
• offset is an Offset object. It specifies the angle from location of the initial subscan.
• scanDuration is a float. It specifies the length of the subscans in seconds.
• beamName is a string. It specifies the receiver beam to use for the scan. beamName can be "C", "1", "2", "3", "4" or any valid combination for the receiver you are using such as "MR12" and "MR34". The default value for beamName is "1".
• calDuration is a float. It specifies the length of the calibration subscans in seconds. The default is 10.0.

Z17 executes two circles of point subscans around location at 45 degree intervals. The first circle with a radius of offset and the second circle at a radius of sqrt(2)*offset. The initial subscan is at the angle specified by the offset. After circling twice, the procedure executes a subscan on location. The entire set of 17 subscans each of length scanDuration, is sandwiched between two cal subscans of lengths calDuration which consist of equal parts calibration noise signal on and off.

This scan type is used for polarization studies.

The following example generates subscan points around 1258+6126 starting the first circle at the source's "right."

Catalog()

Z17("1258+6126", Offset("AzEl", "00:09:00", "00:00:00", cosv=True), 60.0)

SOM: LSFS; Spider

AutoFocus/Peak/PeakFocus(source, frequency, flux, radius, balance, abort)

AutoFocus/AutoPeak/AutoPeakFocus(source, location, frequency, flux, radius, balance, configure, beamName)

The intent of this scan is to automatically peak and/or focus the antenna for current location on the sky and with the current receiver, therefore it should not require any user input, however, if desired, any of its six defaulted parameters may be overridden.

Parameter Info:

• source is a string. It specifies the name of a particular source in the pointing catalog to be used for calibration. The default is None. Specifying a source bypasses the calibrator search. Please note that NVSS source names are used.
• frequency is a float. It specifies the observing frequency in MHz. The default is the rest frequency used by the standard continuum configuration cases.
• flux is a float. It specifies the minimum acceptible calibration flux in Jy at the observing frequency. The default is 20 times the continuum point-source sensitivity.
• radius is a float. The routine selects the closest calibrator within the radius (in degrees) having the minimum acceptible flux. The default is 10 degrees.
• balance is a boolean. Dependent on this argument, after slewing to the calibrator the routine balances the power along the IF chain. The default is True.
• abort is a boolean. If a calibrator cannot be found then either the scan will query the user whether to terminate the block (abort is True) or simply return (abort is False). The default is True.

The intent of this scan is to automatically peak and/or focus the antenna for the current location on the sky and with the current receiver, therefore it should not require any user input. However, by setting any of the optional arguments the user may partially or fully override the the calibration search and/or procedural steps as described below.

The procedure determines the current beam location and receiver, configures the telescope using a standard continuum configuration for the current receiver, selects a nearby calibrator, balances the input levels, and runs the appropriate scan as described below. Note that since the scan is self-configuring, one must re-configure for regular programming. One may examine the candidate sources in Condon's pointing catalog by running calfind directly.

The sequence of events in full automatic mode, i.e, with no arguments are:

1. Get recommended beam, offset(s), and duration for peak and/or focus scans.
2. Get current receiver from the control system.
3. Get current antenna beam location from the control system.
4. Run a configure for Continuum with <receiver> using named configuration cases.
5. Run a balance to obtain accurate system temperature readings from the DCR.
6. Select a source using computed minimum flux, observing frequency, location, and search radius.
7. If no qualified source is found within the radius, then provide the observer the option to use a more distant source (default), and if none found either aborting (second default) or continuing the scheduling block.
8. Slew to source.
9. Run a balance to set scan power levels.
10. Run a scan using either Peak and/or Focus.

Note that these Auto scan types are the only standard scan types that autonomously select a source, configure the telescope, or access a pointing Catalog without additional calls in the block.

Setting optional arguments will cause the scan to skip unneeded steps:

• selecting a source, steps 5, 6 and 7 are skipped
• selecting a location, step 3 is skipped
• selecting a flux, step 5 is skipped
• setting balance as False, step 4 is delayed until just prior to step 10 and steps 5 and 9 are skipped
• setting configure as False, step 4 is skipped

Parameter Info:

• source is a string. It specifies the name of a particular source in the pointing catalog to be used for calibration. The default is None. Specifying a calibrator bypasses the search process. Please note that NVSS source names are used in the pointing catalog. If the name is not located in the pointing catalog then all the user-specified catalogs previously defined in the scheduling block are searched. If the name is neither in the pointing catalog nor in the user defined catalog(s) then the procedure fails.
• location is a Catalog source name or Location object. It specifies the center of the search radius. The default is the antenna's current beam location on the sky.
• frequency is a float. It specifies the observing frequency in MHz. The default is the rest frequency used by the standard continuum configuration cases, or the current configuration value if configure is False.
• flux is a float. It specifies the minimum acceptible calibration flux in Jy at the observing frequency. The default is 20 times the continuum point-source sensitivity.
• radius is a float. The routine selects the closest calibrator within the radius (in degrees) having the minimum acceptible flux. The default is 10 degrees. If no calibrator is found within the radius, the search is continued out to 180 degrees and if a qualifed calibrator is found the user is given the option of using it [default], aborting the scan, or continuing the scheduling block without running this procedure.
• balance is a boolean. Controls whether after slewing to the calibrator the routine balances the power along the IF chain and again to set the power levels just before collecting data. The default is True.
• configure is a boolean. This argument causes the scan type to configure the telescope for continuum observing for the specified receiver. The default is True. Note: because the scan is self-configuring, one must re-configure for regular programming after running the scan type unless configure is set to False. Also be aware that setting configure to False means the observer must insure the DCR in properly configured and included in the Scan coordinator, as the Auto procedures will make no check to the configuration of the GBT.
• beamName is a string. It specifies the receiver beam to use for both subscans. beamName can be "C", "1", "2", "3", "4" or any valid combination for the receiver you are using such as "MR12" and "MR34". The default value is the PTCS recommended value for the receiver. If you configure for one beam, and point with another (using the beamName paramter" you can have very, very bad data. Make sure that if you choose "Configure=False" and "beamName" that the two are compataible!!!

SOM: Focus Peak Corrections

SOM: Focus Peak Corrections

Focus

It is required that you slew to your source before you attempt to focus. If you try to focus without first being on source, the telescope will try to focus at the last location stored in the antenna, which is probably not on your source. You will end up with LFCs that are extremely unreasonable and you will have little or no apparent signal in your data.

Focus

Focus(location, offset, scanDuration, beamName)

Focus(location, start, offset, scanDuration, beamName)

The only required parameter is location.

• location is a float. It specifies the starting position of the subreflector (in mm) for the Focus scan.
• offset is a float. It specifies the ending position of the subreflector relative to the starting location (also in mm).
• scanDuration is a float. It specifies the length of each subscan in seconds.
• beamName is a string. It specifies the receiver beam to use for the scan. beamName can be "C", "1", "2", "3", "4" or any valid combination for the receiver you are using such as "MR12" and "MR34". The default value for beamName is "1".

• location is a Catalog source name or Location object. It specifies the source upon which to do the subscan.
• start is a float. It specifies the starting position of the subreflector (in mm) for the Focus scan. The default value is the PTCS recommended value for the receiver.
• offset is a float. It specifies the ending position of the subreflector relative to the starting location (also in mm). The default is the PTCS recommended value for the receiver.
• scanDuration is a float. It specifies the length of each subscan in seconds. The default value is the PTCS recommended value for the receiver.
• beamName is a string. It specifies the receiver beam to use for the scan. beamName can be "C", "1", "2", "3", "4" or any valid combination for the receiver you are using such as "MR12" and "MR34". The default value is the PTCS recommended value for the receiver. If you configure for one beam, and point with another (using the beamName paramter" you can have very, very bad data. Make sure that if you configure with the same beam with which you Focus!!!

The Focus procedure sweeps the subreflector or prime focus (depending on the receiver in use) through the axis aligned with the beam. Its primary use is to determine pointing offsets for use in subsequent procedures.

The Focus procedure sweeps the subreflector or prime focus (depending on the receiver in use) through the axis aligned with the beam. Its primary use is to determine focus offsets for use in subsequent scans. Note that the offset and scanDuration should be overridden as a unit since together they determine the rate.

The following example assumes that you have already slewed to your source. A focus subreflector is performed from -200 to +200mm at 400mm/min using beam 1:

Important: Because of the addition of the location keyword, Focus will not be backwards compatible.

In the following example a focus subreflector is performed from -200 to +200mm at 400mm/min using beam 1:

Focus("0137+3309", -200.0, 400.0, 60.0, "1")

Focus(-200.0, 400.0, 60.0, "1")

Focus("0137+3309")

SOM: Focus Corrections

SOM: Corrections

The only required parameter is location.

• location is a Catalog source name or Location object. It specifies the source upon which to do the On subscan.
• hOffset is an Offset object. It specifies the horizontal distance used for the Peak.
• vOffset is an Offset object. It specifies the vertical distance used for the Peak.
• scanDuration is a float. It specifies the length of each subscan in seconds.
• beamName is a string. It specifies the receiver beam to use for both subscans. beamName can be "C", "1", "2", "3", "4" or any valid combination for the receiver you are using such as "MR12" and "MR34". The default value for beamName is "1".

• location is a Catalog source name or Location object. It specifies the source upon which to do the subscan.
• hOffset is an Offset object. It specifies the horizontal distance used for the Peak. The default value is the PTCS recommended value for the receiver.
• vOffset is an Offset object. It specifies the vertical distance used for the Peak. The default value is the PTCS recommended value for the receiver.
• scanDuration is a float. It specifies the length of each subscan in seconds. The default value is the PTCS recommended value for the receiver.
• beamName is a string. It specifies the receiver beam to use for both subscans. beamName can be "C", "1", "2", "3", "4" or any valid combination for the receiver you are using such as "MR12" and "MR34". The default value is the PTCS recommended value for the receiver. If you configure for one beam, and point with another (using the beamName paramter" you can have very, very bad data. Make sure that if you configure with the same beam with which you Peak!!!

The Peak scan type sweeps through the specified sky location in the four cardinal directions. Its primary use is to determine pointing offsets for use in subsequent procedures.

The Peak scan type sweeps through the specified sky location in the four cardinal directions. Its primary use is to determine pointing offsets for use in subsequent scans Note that the offsets and scanDuration should be overridden as a unit since together they determine the rate.

SOM: Pointing Corrections

or with the defaults.

Peak("0137+3309")

SOM: Pointing Corrections

• source is a string. It specifies the name of a particular source in the pointing catalog to be used for calibration. The default is None. Specifying a source forgos the calibrator search. Please note that NVSS source names are used.

• source is a string. It specifies the name of a particular source in the pointing catalog to be used for calibration. The default is None. Specifying a source bypasses the calibrator search. Please note that NVSS source names are used.

One may examine the candidate sources in Condon's pointing catalog by running calfind directly.

• source is a string. It specifies the name of a particular source in the pointing catalog to be used for calibration. The default is None. Please note that NVSS source names are used.

• source is a string. It specifies the name of a particular source in the pointing catalog to be used for calibration. The default is None. Specifying a source forgos the calibrator search. Please note that NVSS source names are used.

Please note that the syntax for all Scan Types is case-sensitive.

Please note that the syntax for all Scan Types is case-sensitive.

• source is a string. It specifies the name of a particular source in the pointing catalog to be used for calibration. The default is None.

• source is a string. It specifies the name of a particular source in the pointing catalog to be used for calibration. The default is None. Please note that NVSS source names are used.

Please note that the syntax for all Scan Types is case-sensitive.

A Scan, formerly referred to as an observing procedure, is a pattern of antenna motio