Planet Search 1991, Using a Robotic Photometric Telescope to Search for Extrasolar Planets
Creators: name: Schwehr, Kurt
Publisher: name: Zenodo
Year: 1991
Subjects: astronomy

description: SPDX-License-Identifier: CC-BY-4.0<br> Copyright 1991 Kurt Schwehr. Title: Planet Search 1991, Using a Robotic Photometric Telescope to<br> Search for Extrasolar Planets<br> Kurt Schwehr This was accepted by NASA Ames as a Contractor Report. Who knows what<br> contractor number it got assigned, but it was accepted. TABLE OF CONTENTS 1. INTRODUCTION<br> 2. FIT<br> 2.1 Introduction<br> 2.2 Compiling and linking<br> 2.3 Input files<br> 2.4 Program FIT<br> 2.5 FIT - More Notes<br> 2.6 References<br> 3. TAB<br> 3.1 Generating Data Tables with TAB<br> 3.2 TAB Instruction List<br> 4. PLOT-NIT<br> 4.1 Looking at Night to Night Tables (- Night Table -)<br> 5. PLOT-CLR<br> 5.1 Looking at Within Night Tables (-Color Table-)<br> 6. PLOTTING<br> 6.1 Batch Printing of Graphs<br> 6.2 CLR File<br> 6.3 NIT File<br> 7. PERIOD<br> 7.1 Program<br> 7.2 Synopsis<br> 7.3 Purpose<br> 7.4 Description<br> 7.5 Computer Requirements<br> 7.6.0 Instructions/User Manual<br> 7.6.1 Preparing a data file<br> 7.6.2 Files required to run<br> 7.6.3 Description of a Sample Run<br> 7.6.4 The report<br> 7.6.5.0 Important Definitions<br> 7.6.5.1 Minimum Frequency<br> 7.6.5.2 Nyquist Frequency<br> 7.7 Compiling<br> 7.8 Algorithm<br> 7.9 Program Flow<br> 7.10 Bugs<br> 7.11 Suggestion for future work<br> 7.12 References 1.0 Introduction These programs were written to analyze robotic telescope data from the<br> Fairborn Observatory in Arizona. The programs were developed for William<br> J. Borucki at NASA Ames Research Center by Bob Hogan and Kurt D. Schwehr. Bod<br> Hogan wrote FIT and TAB. Kurt D. Schwehr wrote PLOT-NIT, PLOT-CLR, and<br> PERIOD. This manual was written by Kurt D. Schwehr, except for section 2.0<br> FIT. Direct all questions and comments to: William Borucki<br> MS 245-3<br> NASA Ames Research<br> Moffett Field, CA. The process of data analysis is taken car of by five programs. The data is<br> transferred from the observatory's computer every couple of days. Each ATIS<br> file contains data for one night and is compressed into an archive (ARC).<br> Once the files are on the local computer, the program FIT does some initial<br> data reduction and creates a very large binary data file. The program TAB is<br> used to extract data for each star. The data is stored in ASCII tables that<br> can be inspected, graphed and analyzed. PLOT-NIT and PLOT-CLR will plot up<br> the data for viewing and printing. Finally, PERIOD is used to determine if<br> any of the stars observed are likely to be variable. The next sections<br> describe each of the five programs. 2.0 FIT 2.1 INTRODUCTION This software package is designed to interpret and analyze photometric data<br> originating from an ATIS controlled facility. The package consists of two<br> FORTRAN programs that extract and process photometric counts of selected stars<br> and areas of the sky. The ATIS user must organize photometric measurements<br> into groups. Each group defines a set of star and sky observations. The<br> processing programs use only the relevant information within groups to correct<br> and reduce star data. The programs are FIT, which does the initial data<br> reduction, and TAB which generates ASCII text data tables. 2.2 COMPILING AND LINKING This software should work on all PC, XT, and compatible hardware. The<br> programs were compiled with MircoSoft (MS) FORTRAN 4.0. The modular structure<br> of the codes require linking to an ATIS library in addition to the standard<br> FORTRAN modules. 2.3 INPUT FILES This table indicates all files used and generated by the ATIS software.<br> Identifiers with the dots refer to the filename extensions. The mnemonic<br> identifiers refer to specific files. Input:<br> Catalog.tbl ! Star catalog<br> Refstar.tbl ! List of reference stars for each group<br> A0*.arc ! The ATIS data files compress in an archive<br> Output:<br> Sum.dat ! Summery of the data, stars, and coeff derived.<br> Dat.dat ! Output file required by TAB to calculate the extinction-<br> ! corrected brightness. Generally, all programs need to know where to find their input files, what<br> nights to process, color filter number and what files to create. 2.4 PROGRAM FIT This program is the workhorse of the package. Its function is to compute<br> nightly extinction coefficients using corrected photometric data of selected<br> stars. In addition, all counts are corrected for dead time and the sky<br> component is subtracted from all star counts. The program input requirements are: The data file directory<br> The range of nights to process (JD)<br> Color filter number<br> Accepted upper limit on first order extinctions<br> Accepted upper limit on first order extinction errors<br> Accepted lower limit on air mass differences<br> The output file name The algorithm has been designed for robustness and efficiency. Data is<br> grouped in chronologically ordered time zones. The data collected in each<br> time zone is reduced as follows: 1) Air masses are calculated at all times and counts are corrected for<br> dead time. 2) Sky counts are subtracted from Star counts. Sky counts at times<br> between sky events are found by linear interpolation. 3) Corrected star counts are scanned for outliers by computing a mean<br> count and sigma and searching for counts greater than two sigma<br> from the mean. 4) A two parameter linear extinction model is used to fit data from<br> each extinction star and estimate parameter values and their<br> errors. Outliers are not used. Maximum and minimum air masses<br> are found. The model, MO = MT + E0*X, where: MO is the measured extinction star magnitudes<br> converted from counts as MO = log10(-2.5*counts) MT and E0 are the two parameters estimated E0error is the estimated relative error of E0 X is the air mass<br> DX is the air mass difference (maximum - minimum) 5) A weighted average of the star E0 values is determined. The weight<br> function is the air mass difference. EM = sum ( E0*DX ) / sum ( DX ) sum is over all stars whose E0, E0error, DX values<br> fall inside their user defined bounds. After steps 1) to 5) are performed for each time zone , the set of EM values<br> are used to model the temporal behavior of the extinction. 6) These EM data are used to fit a three parameter model: E0 + E1 * time + E2 * time**2 time is the relative JD time measured from the JD time<br> associated with the first star event of the night. The parameters E0, E1, and E2 are called the nightly<br> extinction coefficients. Program FIT saves the reduced nightly star and sky data and extinction<br> coefficients as fixed length records in a direct access binary file. An ASCII<br> summary file is also generated. <br> 2.5 FIT - More Notes I. Purpose: This program calculates the extinction coeff vs time for each day<br> using the data available from all the stars observed during that night. The<br> only data that are used are those for which the extinction coeff meets the<br> following criteria: 1) 0 .LE. ext. coeff. .LE. MAX (input value)<br> 2) delta air mass change .GE. 0.05<br> 3) relative error .LE. 0.20<br> 4) points in a _____ interval that are ___ are removed. (&lt;- unreadable)<br> 5) if sky .GE. star; toss out the point<br> 6) will not use any star designated as "variable" in the calculation of the extinction coeff.<br> 7) air mass .LE. 2.0<br> 8) 0 .LE. extinction coeff .LE. 1.0 2.6 REFERENCES This material was taken from a readme file from a FIT program disk and notes<br> made by William J. Borucki. It is not necessarily up to date with the latest<br> version of TAB. <br> 3.0 TAB In order to analyze the data retrieved from the Fairborn Observatory's Robotic<br> telescope, I wrote several programs to view the data. These programs can be<br> found on the accompanying disk under the directory \EXE. Also an the disk in<br> the directory \TAB, is Bob Hogan's program TAB2 which generates data tables<br> from the binary file DAT.DAT. 3.1 Generating Data Tables with TAB The program TAB2 is designed to use the data in the binary file DAT.DAT to<br> produce tables of the data. The program requires that two data files are in<br> the current directory: REFSTAR.TBL and CATALOG.TBL. If they are not there,<br> TAB2 will crash. REFSTAR contains the list of the reference star for each<br> group. CATALOG contains the current RA and DEC, magnitude, color index, and E<br> (which is something to do with being a variable star?). Also, TAB2 requires<br> that DAT.DAT be in the current directory. The best way to explain tab is show<br> two examples of generating tables: EXAMPLE 1:<br> Generate a Color Table and a Night Table for HD 114762 DRIVE&gt;TAB2 file<br> days<br> stars<br> extinction<br> coefficients<br> * outliers<br> color<br> night<br> show<br> save<br> print<br> quit &gt;days 1 500 ! Set the date range for finding data &gt;color 114862 ! make a color table for the star<br> ! ** Working ** for a long time<br> &gt;show ! view the table created<br> ** lots of data **<br> &gt;save 114762.clr ! save in the file "114762.CLR" &gt;night 114762 ! generate a night table<br> ! Wait awhile -- the bigger the DAT.DAT the<br> ! longer <br> &gt;show ! Display table<br> ! the night command saves the data for you.<br> ** lots of data **<br> &gt;quit ! Exit to DOS DRIVE&gt;DIR 114762.* ! See what you have created. 114762 CLR 162606 09-13-91 10:58p ! File size may be different<br> 114762 NIT 8938 09-13-91 11:18p<br> 114762 PLT 8282 09-13-91 11:18p ! This is a NIT file without a<br> ! header<br> 3 file(s) 179826 bytes DRIVE&gt; ! Your done EXAMPLE 2: Generate night tables for all stars. DRIVE&gt;TAB2 ! Run tab2 &gt;days 1 500 ! Select JD range &gt;night * ! Create night tables for all stars<br> ! Let run overnight<br> &gt;quit ! Back to DOS This version of TAB does not allow you do what is in example 2 with Color<br> Tables so you will want to use I/O redirection to run a large batch of color<br> tables over night like this: Copy con:redirect.dat<br> days 1 500<br> color 1642<br> save 001642.clr ! always make sure the number here is 6 characters<br> ...<br> ... ! repeat as many times as needed<br> color 300000<br> save 300000.clr<br> quit<br> ^Z<br> TAB2 &lt;redirect.dat <br> 3.2 Tab Instruction List 1) DAYS Define the days that will be considered; firstday, lastday<br> 2) STARS NOT USED<br> 3) EXTINCTION Allows the user to specify the extinction coeff.<br> 4) RATIO star HD #<br> 5)NIGHT compute the nightly mean for those periods when the extinction<br> coeff was calculated<br> 6) SHOW shows the results on the screen<br> 7) SAVE Saves the table to a file specified by the user<br> 8) QUIT quit the program 4.0 PLOT-NIT 4.1 Looking at Night to Night Tables<br> - Night Table - Now that the tables are created, it is possible to view them. To view the<br> night table, use the program "PLOT-NIT". There are three files required for<br> this program to run: the NIT file, your table; "TMSRB.FON", the data file for<br> graphics text; and "SAVE.LST" a file you have to create yourself. The file<br> "SAVE.LST" is very important. You put in it a list of the file names of the<br> tables you wish to inspect. Each line contains the line of the complete file<br> name of one table. Here is a quick way to make the file: DRIVE&gt;copy con:save.lst<br> 114762.nit &lt;enter&gt;<br> ^Z ! Hold down &lt;CTRL&gt; and press Z<br> DRIVE&gt; If you want to view several files at a time, just add each one to a line in<br> this file. You can also use any text editor to make this file. Once you have done this you are ready to view the night table. Start the program: DRIVE&gt;plot-nit<br> The current ranging parameters are: ! controls the range of plot.<br> Minimum: 0.10 Mag ! default settings<br> Maximum: Range of points.<br> Do you like these (y/n): These are the range of the magnitudes displayed. The current settings force<br> the program to have the Y-axis scale show a change of 0.10 magnitude. If you<br> wish to have all your graphs have the same scale, type "n" and &lt;enter&gt;. Then<br> put in the same value for both the maximum and minimum values. If you like<br> the values enter "y" &lt;enter&gt; or just &lt;enter&gt;. The current filter to plot is:<br> filter 3 - VISUAL<br> Do you like this(y/n): Type "y" &lt;enter&gt; or just &lt;enter&gt; if you want this filter to be graphed.<br> Otherwise, to change filters, type "n" &lt;enter&gt;. You will then be asked the<br> number of the filter you want. Next you will be asked if you want error bars. The error bars are taken from<br> the % error list in the NIT table for the filter. Just pressing &lt;enter&gt; is<br> the same as "y" &lt;enter&gt;. Finally, you are asked if you want outliers marked. This function does two<br> things: it shows where the mean value is on the right hand side and it marks<br> points that are outside of one sigma. The outliers are marked with a yellow<br> circle. It was put in for the purpose of drawing attention to points near the<br> top and bottom of the graph, as they can often go unnoticed. Pressing &lt;enter&gt;<br> is the same as "y" &lt;enter&gt;. Here is a sample of what you will see: The Graph Explained The top line of the graph's header contains the information on what the data<br> is being viewed. The second line says the filter plotted, the date the table<br> was made and the Julian Dates (-244800) that this data covers. On the bottom,<br> after the X-Axis label, there are two numbers labeled "Mean" and "NStdDev".<br> The "mean" number is the mean value of the points plotted. The "NStdDev" is<br> the normalized standard deviation of the points. The bottom line of text on the screen is the command menu. Use the left and<br> right arrow keys to move across the menu and &lt;enter&gt; to select an option. The<br> options are: "QUIT" or &lt;esc&gt;, exit to DOS; "NEXT", go to the next table listed<br> in SAVE.LST; "PREV", go to the previous table in SAVE.LST; "PRNT QUE", saves<br> the table name (see BATCH PRINTING); "PRINT", print the graph on the<br> printer(must be an HP LaserPrinter or DeskJet), "ViewData", displays the table<br> used to make the current graph; and "Empty&amp;qu