Space Telescope Science Institute   6.4 Overheads Chapter 7:   FGS Astrometry Data Processing

6.5 Proposal Logsheet Examples


This section provides several examples of RPS2 formatted proposal logsheets for the following types of investigations:

6.5.1 Parallax program using FGS1r in Pos mode

Figure 6.1: illustrates the field geometry and the orient angles of a typical FGS observation, while Table 6.8: summarizes the details of the exposures in the visit.

Figure 6.1: Example 1: Field of View at Special Orientation

Table 6.8: Target and Exposure Input for Example 1
Target
V
FILTER
FESTIME
(default)
Exposure Time
(seconds)
~NEA
for Single
Exposure
(mas)
"OGF_1"a
9
F583W
0.025
20
< 1.0
OGF-3-REFa
11.1
F583W
0.025
20
< 1.0
OGF-7-REF1
10.3
F583W
0.025
20
< 1.0
OGF-9-REF
10.2
F583W
0.025
20
< 1.0
OGF-11-REFa
13.3
F583W
0.050
30
3.1
OGF-12-REF
13.6
F583W
0.050
30
3.5
OGF-21-REF
11.5
F583W
0.025
20
1.0
1The "REF" appendix is not required. Rather its use is suggested simply for book keeping purposes.

 

OGF_1--> 12 -- 11 -- 7 -- OGF_1 -- 11 -- 21 -- 3 -- 7 -- OGF_1

-----> 9 -- 7 -- 11 -- OGF_1 -- 21 -- 12 -- 11 -- 9 -- OGF_1

Visit_Number: 1
 
Visit_Requirements: BETWEEN 14-MAR-1998 AND 15-MAR-1998
 
ORIENT -18.5D TO -19.5D FROM NOMINAL 
 
Visit_Comments: Two Guide Star FineLock Required.Exposure_Number: 01 
 
         Target_Name: OGF_1
 
              Config: FGS
 
              Opmode: POS
 
            Aperture: 1
 
          Sp_Element: F583W
 
   Time_Per_Exposure: 20S
 
Special_Requirements: SEQ 1-4 NON-INT;POS TARG -33,-60.
 

 
     Exposure_Number: 02 
 
         Target_Name: OGF-12-REF
 
              Config: FGS
 
              Opmode: POS
 
            Aperture: 1
 
          Sp_Element: F583W
 
   Time_Per_Exposure: 30S
 
Special_Requirements: SAME POS AS 1; 
 

 
     Exposure_Number: 03 
 
         Target_Name: OGF-11-REF
 
              Config: FGS
 
              Opmode: POS
 
            Aperture: 1
 
          Sp_Element: F583W
 
   Time_Per_Exposure: 30S
 
Special_Requirements: SAME POS AS 1;
 
Comments: 
 

 
     Exposure_Number: 04 
 
         Target_Name: OGF-7-REF
 
              Config: FGS
 
              Opmode: POS
 
            Aperture: 1
 
          Sp_Element: F583W
 
   Time_Per_Exposure: 20S
 
Special_Requirements: SAME POS AS 1; 
 
Comments: 
 

 

...and continues until the orbit is filled.

6-months after Visit 1, the HST Nominal Orient Angle is 180° from the Nominal HST Orientation in Visit 1. Nominal orient angle = 247°, off-nominal orient angle = 228°, pos targ = (+60,+33).

Visit_Number: 2
 
Visit_Requirements: BETWEEN 14-SEP-1998 AND 15-SEP-1998;
 
                    ORIENT -18.5D TO -19.5D FROM NOMINAL 
 
Visit_Comments: Two Guide Star FineLock Required. 
 
Exposure_Number: 01 
 
         Target_Name: OGF_1
 
              Config: FGS
 
              Opmode: POS
 
            Aperture: PRIME
 
          Sp_Element: F583W
 
   Time_Per_Exposure: 20S
 
Special_Requirements: SEQ 1-4 NON-INT;POS TARG +33,+60
 
Comments: 
 
     Exposure_Number: 02 
 
         Target_Name: OGF-12-REF
 
              Config: FGS
 

 

...Continues until the orbit is filled. Visit 3 is identical to Visit 1 except that it executes 1 year later.

Running the proposal template file through APT will inform the observer whether the syntax is correct, whether the exposures fit in an orbit and how much time is left, and finally whether the observing dates are viable for the requested ORIENT angle.

6.5.2 Determining a binary's orbital elements using FGS1r in Trans mode

Figure 6.2: illustrates the geometry of the binary with respect to the POS TARG and detector reference frames.

Figure 6.2: Example 2: Field of View at Special Orientation

 
Visit_Number: 1
 
Visit_Requirements: ORIENT 46.6D TO 48.6D
 
Visit_Comments: Two Guide Star FineLock Required. Please notify Contact Scientist if two 
guide stars cannot be found.
 
Exposure_Number: 01 
 
         Target_Name: Close_Binary
 
              Config: FGS
 
              Opmode: TRANS
 
            Aperture: 1
 
          Sp_Element: F583W
 
Optional_Parameters: SCANS=83, STEP-SIZE=0.6
 
   Time_Per_Exposure: 1729S
 
Special_Requirements: 
 
Comment: 
 
Visit_Number: 2
 
Visit_Requirements: AFTER 1 BY 30D TO 32D 
 
                    ORIENT -24D TO -25D FROM NOMINAL 
 
Visit_Comments: Two Guide Star FineLock Required. 
 
Exposure_Number: 01 
 
         Target_Name: Close_Binary
 
              Config: FGS
 
              Opmode: TRANS
 
            Aperture: 1
 
          Sp_Element: F583W
 
Optional_Parameters: SCANS=83, STEP-SIZE=0.6
 
Number_of_Iterations: 1
 
   Time_Per_Exposure: 1729S
 
Special_Requirements: 
 

 

And similar Visits for 3 and 4.


 

Running the proposal template file through APT will inform the observer whether the syntax is correct, whether the exposures fit in an orbit and how much time is left if they do not; and finally, whether the observing dates are viable for the requested ORIENT angle.

6.5.3 Mass determination: Trans and Pos mode

Texposure = 0.025 * [ScanLength/StepSize] * Nscans

where in this example ScanLength = 1.6 arcsec, StepSize = 0.0006 arcsec, and the number of scans Nscans = 25

Figure 6.3: illustrates the geometry of the target and reference stars, while Table 6.9: and Table 6.10: summarize the details of the exposures in the visit.

Figure 6.3: Example 3: Trans + Pos Mode Visits

Table 6.9: Target and Exposure Input for Example 3
Target
V
FESTIME (use defaults)
FILTER
Total Exposure
~NEA
for one exposure
(mas)
Wide_Binary1
Pos mode
13.0
0.050
F583W
20 sec
2.0
Wide_binary
Trans mode
13.0
0.025
F583W
28 min
Sx = 0.008
BL-1-REF2
10.8
0.025
F583W
20 sec
<1.0
BL-2-REF
14.1
0.100
F583W
35 sec
5.0
BL-3-REF
11.5
0.025
F583W
20 sec
1.0
BL-4-REF
12.5
0.025
F583W
20 sec
1.7
BL-5-REF
13.0
0.050
F583W
20 sec
2.5
1The primary target needs only be listed once in the fixed target list.
2The "REF" appendix is not required. Rather its use is suggest simply for book keeping purposes.

 

Table 6.10: Reference/Check Star Pattern
Mode
Overhead + Exposure Time (Minutes)
GS ACQ + Instrumental Overheads.
12
Trans mode
  • Wide_Binary

28
Pos mode:
  • Wide_Binary
  • BL-3-REF
  • BL-2-REF
  • BL-1-REF
  • Wide_Binary
  • BL-3-REF
  • BL-4-REF
  • Wide_Binary

2
1
2.5
1
2
1
1
2

6.5.4 Faint binary with Trans mode: special background measurements

Figure 6.4 illustrates a possible geometry of the field, while Table 6.11 summarizes the total exposure times for the target and reference star, and dark sky observations.

Figure 6.4: Example 4: Trans + Pos Mode Exposures

 

Table 6.11: Target and Exposure Input for Example 4
Target
V
FILTER
Total Exposure
HDFAINT
Trans mode
15
F583W
39 min.
Dark_Sky1
Pos mode
10
F583W
1 min.
Dark_Sky2
Pos mode
12
F583W
30 S

Specify the background targets to be bright (V=8) to minimize target acquisition overheads. Note: these targets will fail to be acquired in FineLock since no coherent source is present. However, the desired photometry will be recorded.

Visit_Number: 1
 
Visit_Requirements: 
 
Visit_Comments: 
 

 
Exposure_Number: 01
 
         Target_Name: HDFAINT
 
              Config: FGS
 
              Opmode: TRANS
 
            Aperture: 1
 
          Sp_Element: F583W
 
Optional_Parameters: SCANS=69, STEP-SIZE=0.6
 
   Time_Per_Exposure: 1380S
 
Special_Requirements: POS TARG = 0,0 SEQ 1-3 NON-INT
 

 
Exposure_Number: 02 
 
         Target_Name: DARK_SKY1
 
              Config: FGS
 
              Opmode: POS
 
            Aperture: 1
 
          Sp_Element: F583W
 
Optional_Parameters: 
 
   Time_Per_Exposure: 60 S
 
Special_Requirements: SAME POS AS 1
 

 
Exposure_Number: 03
 
         Target_Name: DARK_SKY2
 
         Config: FGS
 
              Opmode: POS
 
            Aperture: 1
 
          Sp_Element: F583W
 
Optional_Parameters: 
 
   Time_Per_Exposure: 60 S
 
Special_Requirements: SAME POS AS 01
 

 

 6.4 Overheads Chapter 7:   FGS Astrometry Data Processing
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