Proposal Logsheet Examples
This section provides several examples of proposal logsheets for the following types of investigations:
1. Parallax Program with Position Mode
- Goal: Determine the parallax and proper motion of star, "OGF_1".
- Scenario:
- The program requires three visits, at 0, 6, 12 months intervals. Best results are obtained if these visits are timed to occur at epochs of maximum parallax factor.
- A special orientation is needed to accommodate target and reference star geometry (for this example). The Orient can be determined from using special tools (e.g., PICKLES or VTT)
- Target Filter: For Science target (V = 9): F583W.
- Reference Star Filter: (all reference stars V > 10)): F583W.
- Reference Star Geometry: Six reference stars near science target; POS TARG required to fit all reference stars in the pickle. See Table 6.1.
- Special Considerations:
- The need for special orientation must be explained in the text justification section.
- The science target must be shifted from FGS1r aperture reference point in order to fit all (i.e., OGF-21-REF) stars in the pickle. Appropriate POS TARG can be determined from PICKLES or VTT. Contact STScI Help desk for assistance if necessary.
- Target Logsheet:
- See Proposal Instructions for guidance.
- Please include color information on all targets if available so color-related calibrations can be assessed by STScI.
Table 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 |
|
|
|
|
|
| OGF-3-REFa |
|
|
|
|
|
| OGF-7-REF1 |
|
|
|
|
|
| OGF-9-REF |
|
|
|
|
|
| OGF-11-REFa |
|
|
|
|
|
| OGF-12-REF |
|
|
|
|
|
| OGF-21-REF |
|
|
|
|
|
1 REF must be included in REFERENCE and CHECK STAR NAMES to inform the planning system that slews between stars are done by moving the FGS IFOV and not the entire HST.
|
- Reference/Check Star Pattern: Check Stars in this observation are REF-7, REF-11, and OGF_1:
OGF_1--> 12 -- 11 -- 7 -- OGF_1 -- 11 -- 21 -- 3 -- 7 -- OGF_1
-----> 9 -- 7 -- 11 -- OGF_1 -- 21 -- 12 -- 11 -- 9 -- OGF_1
- The RPS2 Exposure Logsheet Template: The Optional_Parameters entry is missing since, for this example, all Position Mode Optional Parameters are DEFAULT values
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
Number_of_Iterations: 1
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
Number_of_Iterations: 1
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
Number_of_Iterations: 1
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
Number_of_Iterations: 1
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
Number_of_Iterations: 1
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_Number 3 is similar to Visit 1 since it occurs 1 year later.
Running the proposal template file through RPS2 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.
2. Bright Binary with Transfer Mode
- Goal: To look for a companion to a highly variable Ae/Be star
- Scenario:
- Program requires four visits, once per month.
- Special orientation to accommodate target geometry.
- Target filter: F583W.
- The target "Twin_Shell" has a magnitude V = 13.0.
- The target is essentially a point source, i.e., expected separation of binary if present is less than 40 mas.
- Special Considerations:
- The need for Special Orientation must be explained in the text Justification section.
- Please include color information on all targets especially when Transfer Mode is being used. STScI will use the information to plan the calibration observations of the color reference standard stars.
- Exposure Time Calculation
- Target Magnitude in F583W: 13.0
- FESTIME: 0.025 for all Transfer Mode observations
- FGS Count Rate: 10387.9 counts/sec (2 PMTs-from photometric calibration, Chapter 7).
- Background Count Rate Estimation: 712 counts/sec.
- ScanLength: 1.6 arcsec.
- StepSize: 0.6mas (but binned later to 1 mas).
- Target Visibility Period: 58 Minutes.
- Total Exposure Time: 39 minutes.
- Exposure Time Calculation:
Texposure = 0.025 * [ScanLength/StepSize] * Nscans
where in this example ScanLength = 1.6 arcsec, StepSize = 0.0006 arcsec, and the number of scans Nscans = 35.
Note: This exposure time allows for the overheads described in previous chapters, assuming a target visibility time of ~ 58 minutes.
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 
- The RPS2 Exposure Logsheet Template:
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: TWIN_SHELL
Config: FGS
Opmode: TRANS
Aperture: 1
Sp_Element: F583W
Optional_Parameters: SCANS=35, STEP-SIZE=0.6
Number_of_Iterations: 1
Time_Per_Exposure: 2333S
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: TWIN_SHELL
Config: FGS
Opmode: TRANS
Aperture: 1
Sp_Element: F583W
Optional_Parameters: SCANS=35, STEP-SIZE=0.6
Number_of_Iterations: 1
Time_Per_Exposure: 2333S
Special_Requirements:
And similar Visits for 3 and 4.
Running the proposal template file through RPS2 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.
3. Mass Determination: Transfer and Position Mode
- Goal: Determine the parallax, proper motion, and reflex motion using Position Mode and the relative orbit using Transfer Mode.
- Scenario:
- Program requires two visits every six months for three years.
- Target Filter: F583W.
- Reference Star Filter: F583W.
- Reference Star Geometry: Six reference stars near science target; science target must be placed at aperture reference position for Transfer Mode observations.
- Special Considerations:
- Please include color information on all targets if available so color-related effects can be assessed.
- Exposure Time Calculation:
- Target Magnitude in F583W: 13.0
- FESTIME: 0.025 for all Transfer Mode observations.
- Exposure Time Estimate FGS Count Rate: 10387.9 counts/sec (From photometric calibration, Chapter 7); Background Count Rate Estimation: 712 counts/sec.
- ScanLength: 1.6 arcsec.
- StepSize: 0.6mas (but binned later to 1 mas).
- Target Visibility: 63 minutes.
- Total Transfer Mode Exposure Time: 28 minutes.
- Exposure Time Calculation:
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: Transfer + Position Mode Visits 
Table 6.9: Target and Exposure Input for Example 3
| Target |
V |
FESTIME |
FILTER |
Total Exposure |
~NEA for one exposure (mas) |
| FB4242421 Position Mode |
|
|
|
|
|
| FB424242 Transfer Mode |
|
|
|
|
 Sx = 0.008 |
| BL-1-REF2 |
|
|
|
|
|
| BL-2-REF |
|
|
|
|
|
| BL-3-REF |
|
|
|
|
|
| BL-4-REF |
|
|
|
|
|
| BL-5-REF |
|
|
|
|
|
1 The primary target needs only be listed once in the fixed target list.
2 REF must be included in REFERENCE and CHECK STAR NAMES to inform the planning system that slews between stars are done by moving the FGS IFOV and not the entire HST.
|
Table 6.10: Reference/Check Star Pattern
| Mode |
Overhead + Exposure Time (Minutes) |
| GS ACQ |
|
| TRANS Mode
|
|
POS Mode:
- FG424242
- BL-3-REF
- BL-2-REF
- BL-1-REF
- FB424242
- BL-3-REF
- BL-4-REF
- FB424242
|
|
POS Mode
- BL-3-REF
- BL-1-REF
- FB424242
|
|
4. Faint Binary with Transfer Mode: Special Background and Roll Angle Measurements
- Goal: Observe a faint binary (V = 15.5) in Transfer Mode. Special background observations are needed to insure an accurate background assessment. In addition, the roll angle of HST will be determined empirically using Position Mode observations of the science target and a reference star.
- Scenario:
- Program requires two visits every six months for three years.
- Program requires two orbits per visit to achieve signal-to-noise in Transfer Function.
- Target Filter: F583W.
- Reference Star Filter: F583W.
- Geometry: Target is placed at center of the FOV; the background observation is obtained in a dark region (specified in the proposal as a pointed target); the reference star for the Position Mode observation is also nearby.
- Exposure Time Calculations:
- Target Magnitude in F583W: 15.5
- Transfer Mode Parameters:
- FESTIME: 0.025 for all Transfer Mode Observations.
- Exposure Time Estimate: FGS Count Rate: 1039 counts/sec (From the photometric calibration, Chapter 2); Background Count Rate Estimation: 712 counts/sec.
- ScanLength: 1.6 arcsec.
- StepSize: 1 mas.
- Total Visibility Period: 48 minutes.
- Total Transfer Mode Exposure Time: 23 minutes.
- Exposure Time Calculation:
- Texposure = 0.025 * [ScanLength/StepSize] * Nscans
where in this example ScanLength = 1.6 arcsec, StepSize = 0.0006 arcsec, and the number of scans Nscans = 20
- Background Observation:
- A special background observation is needed because the target is faint and its binary characteristics are at the resolution limit of the FGS1r. The implementation of the background exposure incorporates the following:
- Guide star acquisition: 7 minutes.
- Total Transfer Mode exposure and overhead time: 32 minutes.
- Total Position Mode exposure and overhead time: 6 minutes.
- Select a position of dark sky near the target.
- Specifying the target coordinates of the dark region in RA and DEC rather than POS TARG will guarantee that the same area of the sky is measured in each visit.
- Enter the dark target as a unique entry in the Target Position Logsheet, with the suffix "-REF".
- Specify the dark target to be bright, V = 12, to minimize overheads. The photometry will be available, though the "acquisition" will fail.
- Create a Position Mode exposure line for the dark target, with an exposure time of ~30 seconds. Position Mode is selected for the background measurement simply because it has fewer overheads.
- Position Mode Observations for Roll Determination:
- Position Mode exposures of the faint binary and a nearby reference star are needed to empirically determine the HST roll angle at the time of the observation.
- Observe the binary in Position Mode to expedite data analysis. See Chapter 7.
Figure 6.4 illustrates a possible geometry of the field, while Table 6.11 summarizes the FESTIMES and total exposure times for the target, reference star, and dark sky observations.
Figure 6.4: Example 3: Transfer + Position Mode Visits 
Table 6.11: Target and Exposure Input for Example 4
| Target |
V |
FETIME |
FILTER |
Total Exposure |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
- The RPS2 Exposure Logsheet Template:
Visit_Number: 1
Visit_Requirements: BETWEEN JUN-9-1998 AND JUN-10-198
Visit_Comments:
Exposure_Number: 01
Target_Name: DARK_SKY-REF
Config: FGS
Opmode: POS
Aperture: 1
Sp_Element: F583W
Optional_Parameters:
Number_of_Iterations: 1
Time_Per_Exposure: 30 S
Special_Requirements: SEQ 1-5 NON-INT, SAME POS AS 3
Exposure_Comment: Background Measurement, no target in field.
Special_Requirements: SAME POS AS 03
Exposure_Number: 02
Target_Name: JH-REF-1
Config: FGS
Opmode: POS
Aperture: 1
Sp_Element: F583W
Optional_Parameters:
Number_of_Iterations: 1
Time_Per_Exposure: 20 S
Special_Requirements: SAME POS AS 03
Exposure_Number: 03
Target_Name: HDFAINT
Config: FGS
Opmode: TRANS
Aperture: 1
Sp_Element: F583W
Optional_Parameters: SCANS=35, STEP-SIZE=1
Number_of_Iterations: 1
Time_Per_Exposure: 1333S
Special_Requirements:
Visit_Number: 2
Visit_Requirements: AFTER 01 BY 28D TO 32D
.... and so on.
