Programs for Observation Planning

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Contents 1 online tools 2 Regions_For_Date 3 Plot Skymap 4 Observation Simulation 5 Declination Steps 6 Telemetry Simulation 7 Frame Points Data 8 Geomteric Coeft Inverter

[edit] online tools

Author: Gopakumar

[1]

[edit] Regions_For_Date

regions_for_date.c (code availablein in http://tauvex.iiap.res.in/CVS/--)

author: Gopakumar

This c program gives observable regions based on solar straylight for a date and filter number. The o/p lists RA, DEC and Straylight count. The sorted list is given for three straylight limits: 100, 1000, and 5000 cps over the whole detector. This is a trimmed version of plotskymap.c used to plot map based on straylight.

This program needs:

1. tabsl.txt (straylight file)
2. struct.c

Compile by:

Use the command which will create the executable as regions_for_date :

gcc -lm regions_for_date.c > regions_for_date

Execute by :

Example: ./regions_for_date 2 4 3

Arguments:

1. Arg1: 1-31 (day)
2. Arg2: 1-12 (month)
3. Arg3: 1-5 (1:BBF, 2:SF1, 3:SF2, 4: SF3, 5: NBF3) (filter number)

TODO:

1. date to be dealt with proper range
2. RA will change each day within the 15 day considered. To be included
3. o/p single list for a given SL limit. Now gives three lists
4. o/p list for user given SL limit.
5. include other contributions to SL

[edit] Plot Skymap

plotskymap.c (code availablein in http://tauvex.iiap.res.in/CVS/--)

author: Gopakumar

This c program plots or lists observable regions based on solar straylight for a date, filter number, plot number, and "plot"/"list".

The plot gives Hammer-Aitoff, Polar-North or Polar-South projection. The color scheme is given in each of the plot window itself.

The list gives RA, DEC and Straylight count. The sorted list is given for three straylight limits: 100, 1000, and 5000 cps over the whole detector.

To compile, this program needs :

1. plplot installed
2. tabsl.txt (straylight file)
3. struct.c
4. plplotfns.c
5. plplotfns-polar.c

Compile by:

gcc 'plplot-config --cflags --libs' plotskymap.c

Execute by :

Example: ./plotskymap 2 4 3 1 plot

Arguments:

1. Arg1: 1-31 (day)
2. Arg2: 1-12 (month)
3. Arg3: 1-5 (1:BBF, 2:SF1, 3:SF2, 4: SF3, 5: NBF3) (filter number)
4. Arg4: 1-3 (1: Hammer-Aitoff, 2:Polar-North, 3: Polar-South)
5. Arg5: plot or list (to produce o/p as list or plot)

[edit] Observation Simulation

author: Gopakumar

SimulateData.jar:

This simulates sky observation for one day considering S/C and straylight factors.

[edit] Declination Steps

author: Gopakumar

Find next declination for a given exposure time.

The method:

1. Take a reference point in sky

2. Calculate a rough scan step from exposure time needed and that maximum available from one scan.

3. Calculate exposure time for each exposure to the source, assuming it is exposed for maximum time during that scan. The expression is eqn(1), where the cos(delta) =1 in this case.

4. Compare with required time.

5. If the exposure time is $> $ required time, we got exposure for a source in sky where maximum FOV is available during scanning. Now find exposure time for the point in sky in the same FOV where exp time is minimum. This point is where next scan FOV should start. The shift or step is found to satisfy this condition. So this range from maximum to minimum, and towards the other side of maximum also, is not covered by next scan or previous scan. It is also verified whether the next region is getting required exposure. If not the step is reduced and done again.

This condition can be relaxed by finding the minimum point such that the average is the required time, or as Rita suggested take the minimum exposed point where exp time is $80 \% $ of required time.

Used the eqn,

exptime1 = t0. cos(delta) / cos(decl)

where, $t0= 215.4 sec = 86160/360 * 0.9 $.

$decl = declination $.

$ delta = -90^0 ~ to~ +90^0 $, which is from scaling $-0.45^0 ~to ~ +0.45^0 $ of FOV range, relative to the scan maximum.

So for maximum exposure the $ cos(delta) =1$, and this term goes to $0$ towards edge of FOV.

This expression is valid for $decl= 0~ to ~89.856$, since beyond that the $result ~>~ 86400 sec$.

6. If the required time is not reached for the reference point in one scan, then

a). Exposure time for one scan is found first.

b). Using the rough scan step the exposure for the ref point is calculated

c). Repeat b) for all steps that contribute to the ref point.

d). Add the above exposures for the ref point in sky.

e). This is done for all previous scan also that will contribute.

f). Add the above and compare with require time.

g). If more than required then increase the step, or reduce the step if the other way.

7. Find match, output this step.

8. Repeat by giving new dec= olddec +step.

[edit] Telemetry Simulation

author: Gopakumar

SimTelemetry.jar: This is GUI based in java.

simtelemetry.c:

This gives telemetry.txt file as o/p, which is to be used to simulate level0 binary data for running data pipeline program. This contains 128ms frames containing telemetry message and other useful information.

[edit] Frame Points Data

frame_points_sim.c

author: Gopakumar

This is for testing purpose only. This simulates ascii data for artificial points in the 1024x1024 pixel frame, with scan or no scan.

[edit] Geomteric Coeft Inverter

GeomDistCft.java

author: Gopakumar

This java program can be used to invert cfts between those that produces and corrects distortion. This uses a class for matrix inversion obtained from net (name ?)