Bruce Greenawalt - responsible for maintance of this tutorial page and automation scripts. He also has some experience with reducing both APO20 and USNO40 data.
Douglas Tucker - mtpipe cordinator. He is responsible for much of the MT pipeline and has extensive knowledge concerning the reduction of all MT data.
J. Allyn Smith - oberver on USNO telescope. He has extensive experience reducing USNO data, which has some similarities to the APO20 data.
It is assumed that the mjd is known from the outset.
Determining the tape which contains the data for that night is a simple process and can be determined in several ways. One may manually inspect the tapelogs in the directory /data/dp3.a/mt/tapelogs or check the mailing list, here. To make things easier, one can use some dp procedures to find the correct tape.
This document will deal primarily with data taken on the 20" telescope at Apache Point Observatory (APO). This telescope is referred to as the apo20.
The data for mjd51318 was read in from tape JL1136. Therefore the raw data can be found at /data/dp3.a/mt/dp/apo20/spool/JL1136/51318.sdssdp3> pwd /export/data/dp3.a/mt/dp/apo20/spool/JL1136 sdssdp3> ls 51317 51318
There are a few automation scripts included in the dp product which make some steps of the reduction easier. These are detailed below. However, it is suggested that these should be used after one is comfortable with reducing the data in the method detailed below. Therefore, one has a better sense of how to handle strange situations with the data that are sure to come up. In addition, one will hopefully be able to separate problems in the automation scripts from problems with the data.sdssdp3> pwd /export/data/dp3.a/mt/dp/apo20/run sdssdp3> ls JL0903 JL1054 JL1160 opFiles_temp JL0906 JL1110 JL1161 secondary_patches JL0907 JL1127 listed_by_mjd temp_log JL0921 JL1131 mtreports_cleaned JL1027 JL1136 mtreports_raw
sdssdp3> cd /data/dp3.a/mt/dp/apo20/run/mtreports_raw sdssdp3> cp mdReport-51318.par mdReport-51318a.par
sdssdp3> setup mt sdssdp3> mtpipe mtpipe> clean_report mdReport-51318a.par
mtpipe> source mdFix.tcl mtpipe> mdFix 51318 1
Print out the editted mdReport file in landscape format if you are keeping a paper trail. The following command works well for printing out the mdReport file in a readable format:sdssdp3> cd /data/dp3.a/mt/dp/apo20/run sdssdp3> mkdir JL1136 sdssdp3> cd JL1136 sdssdp3> mkdir mjd51318 sdssdp3> cd mjd51318 sdssdp3> cp ../../mtreports_raw/mdReport-51318b.par mdReport-51318.par
sdssdp3> a2ps -1 -l mdReport-51318.ps | flpr -q wh6e_hp5si
If one wants to read in the second tar file ALSO, then two file markers must be skipped before the second tar file can be read. This will also work for any additional tar files.sdssdp3> mt -f `ocs_devfile -t sdss30` fsf 1 sdssdp3> tar -xvf `ocs_devfile -t sdss30`
If one only wants the second tar file then use the following commands:sdssdp3> mt -f `ocs_devfile -t sdss30` fsf 2 sdssdp3> tar -xvf `ocs_devfile -t sdss30`
A general rule applies here. To read in the Nth tar file from a tape, one must first skip forward (2N-1) file markers.sdssdp3> mt -f `ocs_devfile -t sdss30` fsf 3 sdssdp3> tar -xvf `ocs_devfile -t sdss30`
After this finishes, create the symbolic link from the listed_by_mjd directory to the tape-label directory.mtpipe> preMtFrames /data/dp3.a/mt/dp/apo20/spool/JL1136/51318 \ /data/dp3.a/mt/dp/apo20/run/JL1136/mjd51318 APO20 51318 1
Look at the tutorial guide about running preMtFrames.mtpipe> cd /data/dp3.a/mt/dp/apo20/run/listed_by_mjd mtpipe> ln -s /data/dp3.a/mt/dp/apo20/run/JL1136/mjd51318 mjd51318
hgBiasFrames-51318.ps hgFlatFrames-51318.psUse ghostview to look at these files.
or in bash. The STDOUT and STDERR from mtFrames will be put in the file mtFrames.out. One can "watch" this output by using the tail command.sdssdp3> cd /data/dp3.a/mt/dp/apo20/run/listed_by_mjd/mjd51318 sdssdp3> mtpipe -command "mtFrames -onlyflat -verbose=3" \ >>&! mtFrames.out & sdssdp3> mtpipe -command "mtFrames -skipbias -skipflat -dropobj \ -dropimages=5 -verbose=2" >>&! mtFrames.out &
When mtFrames ends, you will need to do a CTRL-C to exit out of tail.sdssdp3> tail -f mtFrames.out
This can often be omitted. But since it doesn't take very long to run, we will make the check here. If there are problems you can look at the tutorial guide about internal consistency of the standard star file.mtpipe> set fcDir [envscan \$MTSTDS_DIR]/primary mtpipe> check_standard_file $fcDir metaFC.fit
or in bash. While determining the solution, you will be presented with plots showing the residuals between the data points and the fit. The horizontal dashed lines on these plots will show the rms residuals. We would like these rms values to be less than .02 in u and less than .01 in the other filters. If the residuals are greater than these values and there are points with large residuals on these plots, then we want to delete these points from the fit. Simply place the cursor near the point to be deleted, then press the "d" key. To undelete a point press the "u" key when the cursor is near the point of interest.sdssdp3> cd /data/dp3.a/mt/dp/apo20/run/listed_by_mjd/mjd51318 sdssdp3> mtpipe -command "excal -drop -verbose=4" >>&! excal.out & sdssdp3> tail -f excal.out
Look at the tutorial guide about creating charts for the secondary patches.sdssdp1> cd /data/dp3.a/mt/dp/apo20/run/listed_by_mjd/mjd51318 sdssdp1> setup ko sdssdp1> ko ko> koGenMTGSC mdReport-51318.par Sec 1.0 ko> sessionEnd ko> quit
or in bash. Then to follow the output being placed in the file kali.out simply use the tail command.sdssdp3> cd /data/dp3.a/mt/dp/apo20/run/listed_by_mjd/mjd51318 sdssdp3> mtpipe -command "kali -verbose=4" >>&! kali.out &
Look at the tutorial guide about calibrating the secondary patches.sdssdp3> tail -f kali.out
qa_kali-51318.psThe first of these, qa_kali-51318.ps, contains 5 plots. We are most concerned with the last 3, but the first is also important.
qa_kali-51318_MTsanity.ps
The first plot shows the percentage of objects matched in each Secondary patch during the night. You want to check to make sure that there aren't many sequences with zero (0) matches.The second file, qa_kali-51318_MTsanity.ps, compares determined stellar magnitudes for stars in overlap regions between Secondary patches. Not all Secondary patches have overlap, so there may not be many data points in the plot for the night you reduce. This file consist of a single page of 15 plots divided into three (3) rows. Each row consists of different types of plots which try to illustrate the variations in stellar magnitudes for the same stars observed in two Secondary patches. Within a row there are five (5) plots, one for each filter, u, g, r, i, z.
The last three (3) plots show color-color plots for the stars in the Secondary patches. There are curves on the first two (2) of these plots showing the positions of main sequence stars. We expect some scatter in these plots, but basically the bulk of the data points should follow these curves. In the third plot, the stars are tightly grouped just to the upper right of (0,0) then there is a tail towards the upper right. The main thing to look for in these plots is that most stars fall along a single sequence. The presence of a parallel sequence is a sure sign of trouble.
The first row of plots show the raw magnitude difference as a function of magnitude for stars in overlap regions. In each plot the distribution of points should be narrow at the left edge, centered around zero (0). The distribution should spread out as one moves towards fainter stars, towards the right. If the distribution is centered significantly above or below a zero (0) magnitude difference then there may be a photometric offset in one of the patches providing overlap regions. This suggests that there are problems with the photometric solutions at some stage of the reduction.If you notice problems with any of the kali output, some stage of the reduction must be redone. As of now, deciding what went wrong and why is difficult at best. The best guess is to talk with either Douglas Tucker or Bruce Greenawalt. Look at the tutorial guide about performing QA on kali output.
The second row shows the magnitude difference in units of standard deviations. The distribution should be roughly uniformly wide at all magnitude levels and centered on a zero (0) difference. Again, look for distributions that are significantly offset from a zero difference.
The third row contains histograms of the magnitude differences in units of standard deviations. The distributions in these plots should be roughly gaussian shaped with about 68% of the data with two (2) sigma of the center, which should be near zero (0).