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Last Updated: Wednesday, 05-Dec-2007
Responsible NASA Official: Joe Gurman
Content & Techincal Contact Person: Dawn Myers
Revision 4: T. D. Tarbell, 30-May-00
These recipes give the TRACE planner instructions on running the
various "daily" and "monthly" calibrations, and
some occasional calibrations,
which are run only on request. Recipes for avoiding periods of high
particle radiation (SAA and high latitude zones--HLZ's) are also
included.
When the instrument is idle (no sequence running, no pointing maneuver in progress), run focus.utim, which takes under 5 minutes. Pointing and radiation are irrelevant. This takes over 20 commands and so is not usually run on weekends.
STD.CDSsynoptic should be run daily, although it may be skipped
occasionally to accommodate a continuous run on another target.
It takes 20 - 30 minutes, depending on the length of pauses during
high radiation period. It may be run directly or using
baseline.utim, which includes some additional reset sequences. It
is usually run during the interval of the CDS (on SOHO) synoptic
program, 00:00 - 06:00 UT, but this is not essential.
The standard "monthly" calibrations are the following:
FOCUS: WL and UV, EUV, Lyman alpha
ISS:
PZT and GT calibration in each axis
CCD: dark set, light transfer
curve
ALUMINUM FILTERS: front &
back
FLAT FIELDS: WL, 1700 and 1216
SAA and AAZ (atmospheric absorption zones) are shown in the timeline program; both are fairly accurate but not perfect. Very short SAA's (< ~5 minutes) don't really happen. To learn the HLZ times without cluttering the timeline with commands, run any of the IDL routines as follows, for the time period of interest:
high_mag_lat, ['01-mar-99 00:00','01-mar-99 06:00'], latm, times
This makes a screen plot for the requested time interval showing the SAA's as ***** and the HLZ's as bars with a dashed line. The bars with a solid line are extremely generous HLZ's: avoid these times to be absolutely sure of minimal radiation.
tr_plot_hlz, '01-Mar-99', /hc
This prints four 6-hour plots of the type described above.
hlz_to_utim, '60', '1999' ; DOY 60 is 01-Mar-99
This makes the utim file /tsw/obs/utim/HLZ_199960.utim with the register set and clear commands at HLZ entry and exit times. (You must be logged in as trace to write into this directory.) This can be read for "exact" times without filling the timeline with the commands.
0) Choose a 10 minute period with no SAA and preferably no HLZ
2) After a few minutes for the pointing to stabilize, run
STD.focus_wluv, which takes ~5 minutes
0) Choose a 12 minute period with no SAA and no HLZ
2) After a few minutes for the pointing to stabilize, run
STD.focus_euv, which takes ~10 minutes
0) Choose a 10 minute period with no SAA and no HLZ
2) After a few minutes for the pointing to stabilize, run
STD.focus_lyman, which takes ~2 minutes
There are four completely self-contained .utim files for the normal ISS calibrations. These run jitter mode to calibrate the guide telescope error signal and PZT gains in each axis. Each one takes 10 minutes, uses many commands, and puts very little data in the mass memory. I wouldn't run them during SAA (though I don't really think it makes any difference), but HLZ is OK. The files are:
STD.gt_x_axis.utim
STD.gt_z_axis.utim
STD.pzt_x_axis.utim
STD.pzt_z_axis.utim
Run STD.dark_set in an 8 minute period with no SAA and preferably no HLZ. Pointing is irrelevant.
Point to a quiet region near sun center pointing using STD.repoint_top1. Then run the following four sequences; HLZ is undesirable, but not really fatal
STD.ltc_wl -- takes 4 minutes
STD.ltc_1700 -- takes 6 minutes
STD.pinholes_euv -- takes about 13 minutes
COM.af1_front_al -- takes 2 minutes
Alternatively, you can use the file cal_filt_ccd.utim, which runs all five of these sequences and takes about 36 minutes (including a 4 minute stop and wait at the beginning). This will run into HLZ, which is tolerable as long as the first 20-25 minutes of observing ar low radiation time.
We now (Spring, 2000) make flats in WL without the Fused Silica filter, 1700 and 1216. These should be run avoiding SAA; HLZ is undesirable but tolerable for WL. There are two .utim files which run the flat field procedures: wl_noFS_flats_best.utim does WL in about 11 minutes, and 1700_flats_best.utim does 1700 in about 17 minutes. The latter takes longer because it uses the wedges & ACS to point at three different targets instead of just one. The pointing must be to very quiet sun near disk center. In both utims, the pointing coordinates must be changed if disk center (0,0) will not give a full field of view with no active regions or plage in it. After including the utims in the timeline, modify both the "PNT top1.pos1 0 0" commands to show the desired coordinates, for example -80 110 to avoid some plage SW of disk center. Then edit the next two PNT commands in the 1700 procedure, so they reflect offsets of (+/-70,0) and (0,+/-70) from the first position. The +/- signs are chosen to avoid active region and plage. So the example would be as follows:
Original command in the utim Modified in the timeline
PNT top1.pos1 0 0
PNT top1.pos1 -80 110
...
PNT top1.pos1 0 0
PNT top1.pos1 -80 110
...
PNT top1.pos1 70 0
PNT top1.pos1 -150 110
...
PNT top1.pos1 0 70
PNT top1.pos1 -80 180
The 1216 flat field is made by 1216_flats_best.utim, which works in
exactly the same way as the 1700 procedure. Edit the PNT commands
to the same coordinates as for 1700 (or updated for solar rotation if
necessary).
Choose a period of at least 2 hours with no SAA, and plot the radiation zones for it. Run STD.dark_set every 12-15 minutes or so in the radiation-free times; it takes 8 minutes each time. Atmospheric absorption and eclipse are irrelevant, of course, since these are darks. See 5 October 1999 for an example.
Estimates of sensitivity loss in EUV wavelengths can be made using FF171.utim, FF195.utim and FF284.utim. Each of these needs about 20 minutes in a low radiation period, pointed at a large but feeble active region or plage. Flaring regions must be avoided--they take ~25 fixed, long exposure EUV frames. Coordinates should be edited in the timeline, setting top1 to the center of the AR, then shifted right, left, up and down. The comments give further details.
This is done with images in each wavelength at each of the "four limbs," both poles and on the equator. Run NSEW_all_waves.utim in a 20 minute period of low radiation.
This is done by taking WL images of the four limbs repeatedly. Run NSEW_WL.utim for at least 20 minutes, avoiding SAA but HLZ is OK.
1216L and 1550L wavelength frames and their relatives. I don't find any .utims for them, at a glance. These should be done both on the disk (AR) and on a prominence above the limb.
TDT.uv_subpixel takes UV and EUV (171 & 195) images with sub-pixel offsets using the PZT's. It can take them at different focus positions to get the best possible quality for each wavelength. Target should be a non-flaring AR. The sequence needs some rewriting, so a .utim is not available at the moment.
Someday I will try again with narrow focus scans with PZT's centered and then tilted almost as far as possible (imqual.utim--not up to date).
This can be estimated from the radiation test frames taken in EUV wavelengths with both quadrants, so no special calibration is needed.
At a fixed azimuthal angle around the limb, take a series of images at different radii, starting a few arcminutes inside the limb and stepping out as far as desired in 1-2 arcminute steps. The scattered light (in WL) appears to be largest at 45 degree positions, (NE, SE, SW, NW) and smallest at the poles and equator.
Take bursts of small WL images using TDT.ptg_WL.utim or of 1600 images using TDT.ptg_stability.utim. The latter is also an interesting scientific observation, if the target is an AR or sunspot on the disk and SAA and HLZ is avoided. Pointing coordinates need editing. The duration can be changed by editing the time of the final STOP. Yet another set of ISS calibrations are TDT.iss_x_axis.utim and TDT.iss_z_axis.utim: 8 minutes each, no editing needed, avoid SAA.
Wish I knew how to do it...Roll stability may be estimated by running ptg_cal.utim for an orbit.
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GSFC Homepage
Last Updated: Wednesday, 05-Dec-2007
Responsible NASA Official: Joe Gurman
Content & Techincal Contact Person: Dawn Myers