4.1.1 Common parameters
4.1.2 Scan pattern
• Strip scan
• Map (single-grid)
• Map (multi-grid)
• Random positions
• Five points
• Spiral scan
4.1.3 Tips

4.1.1 Common parameters

Fig 4.1  Scan Table Window

 
File Name : Name of Scan Table to save.

On Positions

Scan Pattern : Select a scan pattern from the list shown by pushing the button. A window to set parameters appears except for Center (one-point).

Center (one-point) : To observe the coordinate of a source defined in Source Table.
Strip Scan : To observe equally spaced points along a strip.
Map (single-grid) : To observe a rectangular area.
Map (multi-grid) : To observe a rectangular area. Two grid spacings can be defined. This is useful for observations with BEARS with a smaller spacing than the beam separation.
Random Positions : To observe random positions. Coordinates of 40 ON positions can be defined.
Five Points : To observe 5 (or 9) points like a cross. This pattern is mainly used for pointing.
Spiral Scan : To observe a square area with single grid spacing like a spiral from the center.

Integration Time : Integration time for ON position. Typical value is 20 sec.

 
On Point Numbers : Numbers of start point and end point of ON positions. If you observe all ON positions defined in Scan Pattern, enter "1-total number of ON positions". You can observe some specified ON positions among the positions defined in Scan Pattern by using this parameter. Three sets can be defined.

Off/Calib Positions

Coordinate System : Coordinate system for OFF positions.

Coordinate Mode : Definition of OFF positions.
 
offset from center : Offset from the coordinate of a source defined in Source Table.
                                (ddd mm ss.s, ddd mm ss.s)

absolute value : Absolute value on the specified coordinate system.
 

Coordinate Values (1) - (8) : Coordinates of OFF positions. 8 OFF positions can be defined.  For frequency switching and beam switching, OFF position (1) is used for calibration.
Sequence : Observation sequence is defined by On Point Numbers, Sequence Pattern, and Number of Sequence (see examples).
 

Sequence Pattern : Sequence pattern of ON positions (*) and OFF positions (1 - 8). Do not specify OFF positions (1 - 8) for frequency switching observations.

Number of Sequences : Total number of scan per one ON position.

 

Calibration : Parameters for intensity calibration.
 
Calibration Mode : Select a calibration system for intensity calibration.
R-SKY : Default
LDM2-SKYM2 : BEARS
LD1-SKY : S115Q
Integration Time : Integration time for calibration. In general, this is set to be the same as the integration time of ON position.

Interval : Number of Sequence Pattern between intensity calibrations. Typical value of the interval time of the calibration is 10-20 min.  You should decide this parameter considering the weather condition.
 

Switching Mode Options : You can use frequency switching instead of position switching.

Frequency Switch
Beam Switch (not avilable)

 

Auto Integration : Integrated data of all scan is created for each ON position automatically. Raw data are removed.

Auto Stop : You can stop your observation automatically, when the noise level becomes lower than a threshold that you define.

on

• Parameters for frequency switching
 

Fig 4.2  Frequency Switch Window



Throw Rate (Synthe 1 - 4) : Throw rate of frequency. The throw rate can be defined for 4 synthesizers individually.

Modulation Rate :

time per phase : Integration time of one phase in one cycle.

Switching mode :

single : Frequency of local oscillator is switched to one side (upper or lower).
double : Frequency of local oscillator is switched to both side (upper and lower).


switch rate : If you use only AOSs, select 0.25Hz (time per phase = 2.0s).

* Since the integration time unit is 2 (single) or 4 (double) times time per phase, Integration Time (common parameter) of ON position have to be a multiple of the unit.

Specifications of frequency switching is here
 

• Parameters for beam switching    (not available)
 

Fig 4.3  Beam Switch Window


Switching Mode :
Beam Separation :
Switching Frequency :

• Parameters for auto stop

Fig 4.4  Auto Stop Window

Ref. Array : Select a spectromer to measure rms noise level.
RMS Limit : Threshold value of rms noise level to stop observation.
Mode :

POINT : If you observe only one ON position, use this mode.
MAP : For mapping observations, use this mode.

No. of Ref. ON Poistion (MAP) : For MAP mode, you have to define an ON position as reference point to measure rms noise level.

4.1.2 Scan pattern

• Strip Scan


Fig 4.5  Strip Scan Window


Coordinate System : Coordinate system for ON positions.

Position Angle : Position angle of a strip of ON positions on the specified coordinate system. (+ : CCW)

Start Position : Coordinate of the start position. The origin is the coordinate of a source defined in Source Table.

Grid Spacing : Grid spacing of ON positions. Scan direction is defined by +/ -.

Grid Number : Number of ON position.

 



Fig 4.6  Scan pattern of the above Scan Table.

---

• Map (single-grid)


Fig 4.7  Map (single-grid) Window


Coordinate System : Coordinate system for ON positions.

 

Position Angle : Position angle of a map on the specified coordinate system.  (+ : CCW)

Start Corner : Coordinate of the start position.  The origin is the coordinate of a source defined in Source Table.

Grid Spacing : Grid spacing of X and Y directions.  Scan direction is defined by +/-.

Grid Number : Grid numbers along X and Y axes.  Total number of ON positions must be less than 10000.

Initial Direction : Initial direction of scan.
 



 
 
 
 
 
 

Fig 4.8  Scan pattern of the above Scan Table.

• Map (multi-grid)


Fig 4.9  Map (multi-grid) Window


Coordinate System : Coordinate system for ON positions.

Position Angle : Position angle of a map on the specified coordinate system. (+ : CCW)

Large Grid : Large grid of mapping. After small grid points around one large grid point is scanned, the telescope moves to the next large grid point and starts scan of small grid points.
 

Start Corner : Coordinate of the start position. The origin is the coordinate of a source defined in Source Table.
 

Grid Spacing : Grid spacing of X and Y direction. Scan direction is defined by +/-.

Grid Number : Grid numbers along X and Y axes.  Total number of ON position must be less than 10000.

Initial Direction : Initial direction of scan.
 

Small Grid :
 

Grid Spacing : Grid spacing along X and Y axes.  Scan direction is defined by +/-.

Grid Number : Grid numbers along X and Y axes.  Total number of ON position must be less than 10000.

Initial Direction : Initial direction of scan.



Fig 4.10  Scan pattern of the above Scan Table.

• Random Positions


Fig 4.11  Random Position Window


Coordinate System : Coordinate system for ON positions.

Position Angle : Position angle of a map on the specified coordinate system. (+ : CCW)

Point (1) - (40) : Coordinate of ON positions.  40 ON positions can be defined.

• Five Points


Fig 4.12  Five Points Window


Observation Mode : For pointing observation, select pointing.

Coordinate System : Coordinate system of scan.

Position Angle : Position angle of scan on the specified coordinate system. (+ : CCW)

Number of Positions : Number of ON positions. Since the center is observed twice in one cycle, total number of ON positions is 6 for 5 points and 10 for 9 points.

Grid Spacing 1 : Position offset (of the inner points for 9 points) from the center.

Grid Spacing 2 (for 9 points) : Position offset of the outer points from the center.
 



Fig 4.13  Scan pattern of the above Scan Table.

• Spiral Scan


Fig 4.14  Spiral Scan Window


Coordinate System : Coordinate system for ON poisition.

Start Position : Coordinate of the start position.  The origin is the coordinate of a source defined in Source Table.

Grid Spacing : Grid spacing of ON positions.

Specify Map Area by: You can define map size by length or number of grid.

Area Side Length : Length of one side of map. Grid number is N = (INT)(Area Side Length / Grid Spacing). If N is even, N = (INT)(Area Side Length / Grid Spacing) + 1.

Side Grid Number : Grid number of one side of map. If you enter an even number, it is added by 1.

Initial Direction : Initial direction of scan.

Position Angle : Position angle of initial direction of scan. (+ : CCW)

Spiral Direction : Direction of spiral scan.

 



Fig 4.15  Scan pattern of the above Scan Table.

4.1.3 Tips

• Total number of ON position

 
Center (one-point) : 1
Map (single-grid) : X Grid Number × Y Grid Number
Map (multi-grid) : (X Grid Number× Y Grid Number : Smalll Grid) × (X Grid Number × Y Grid Number : Large Grid)
Five points : 6 or 10
Spiral scan : N = (Side Grid Number)² or {(INT)(Area Side Length / Grid Spacing)}²
   If N = even,
   N = (Side Grid Number + 1)² or {(INT)(Area Side Length / Grid Spacing) + 1}²

 
• Observation sequence
 
e.g.1) On Point Numbers : 1-4
          Sequence Pattern : 1**
          Number of Sequence : 2

            OFF1, ON1, ON2,
           OFF1, ON1, ON2,
           OFF1, ON3, ON4,
           OFF1, ON3, ON4

 
e.g.2) On Point Numbers : 1-4
          Sequence Pattern : 1**1**
          Number of Sequence : 2

            OFF1, ON1, ON2, OFF1, ON3, ON4,
           OFF1, ON1, ON2, OFF1, ON3, ON4

e.g.3) On Point Numbers : 2-6
          Sequence Pattern : 1**2**
          Number of Sequence : 2

            OFF1, ON2, ON3, OFF2, ON4, ON5,
           OFF1, ON6, ON2, OFF2, ON3, ON4,
           OFF1, ON5, ON6
 

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