postscript and txt
One main goal of this run is to map out the galactic center using 6 Mosaic pointing (WANG_GCs) to cover 30 Galactic center Chandra observations. So these 6 pointings are given the the highest priorities. The rest of the priorities are sorted by nH, Exp, glat, and field X-ray and optical background. 1 is the highest priority, 15 is the lowest priority.
Following is the target list in the order of increasing RA. The RA and Dec in the list are the telescope pointings, i.e. the center of the MosaicII (not the coordinates of the targets or the Chandra), based on the overlay of Mosaic II on ACIS. NO MORE OFFSET IS NEEDED.
Champlane CTIO 4m/MosaicII Target list May 13-17, 2002
Telescope pointing
Center of Mosaic II Chandra Chandra
Pri Field Observed? RA Dec (J2000) glong glat Detect Exp NH
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9 RCW38 N 08 58 57.60 -47 26 10.0 267.87099 -1.02544 ACIS-I 100.00 8.53E+21
14 MSH11-62 N 11 12 06.40 -60 41 36.0 291.07051 -0.12979 ACIS-S 50.00 1.46E+22
13 G292.2-0.5 N 11 19 03.40 -61 30 18.0 292.14683 -0.58296 ACIS-S 60.00 1.30E+22
11 CENX-3 N 11 20 51.20 -60 37 24.0 292.04575 0.31945 ACIS-I 40.00 1.30E+22
10 MYCN18 N 13 39 34.70 -67 20 27.0 307.55780 -4.90206 ACIS-S 40.00 4.27E+21
8 1RXSJ161411 N 16 14 49.40 -63 12 21.0 323.65143 -8.84169 ACIS-I 33.40 1.66E+21
7 MARS N 17 00 45.95 -26 56 00.1 356.07741 9.31750 ACIS-I 30.00 1.59E+21
12 XTEJ1723-376 N 17 24 09.30 -37 41 32.6 350.21655 -0.97519 ACIS-I 30.00 1.33E+22
5 Wang_GC5 N 17 43 04.80 -29 37 48.0 359.12038 0.10918 ACIS-I 24.00 1.09E+22
2 Wang_GC2 N 17 44 00.00 -29 01 48.0 359.73635 0.25338 ACIS-I 24.00 1.09E+22
3 Wang_GC3 N 17 45 44.88 -28 25 48.0 0.44816 0.24004 ACIS-I 24.00 1.09E+22
6 Wang_GC6 N 17 45 49.20 -29 37 48.0 359.43188 -0.39826 ACIS-I 24.00 1.09E+22
1 Wang_GC1 N 17 46 43.20 -29 01 48.0 0.04642 -0.25393 ACIS-I 24.00 1.09E+22
4 Wang_GC4 N 17 48 27.60 -28 25 48.0 0.75723 -0.26983 ACIS-I 24.00 1.09E+22
15 GALACTICPLANE N 18 43 26.52 -03 58 48.0 28.48047 -0.03868 ACIS-I 200.00 2.07E+22
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Click a object name to see the MosaicII & ACIS overlay on DSS image. This should help to identify the field. Note that the DSS images are E-left & N-up. But the MosaicII display at the CTIO is E-up & N-right.
Do dithered exposures for the long exposures are very important. Not only it fills up the gaps between the chips and eliminate bad columns to make a cosmetically clean image, it also greatly reduce the "bleeding" effect caused by saturated bright stars.
Exposure sequence for each field
Filter Frame Exp Exp+readout Total Timeline
(sec) (min/frame) (min) (min)
------------------------------------------------------
R single image 2 1.7 1.7 1.7
Ha single image 30 2.2 2.2 3.9
R dither 1x5 240 5.7 28.5 32.4
Ha dither 1x5 1500 26.7 133.5 165.9
V single image 2 1.7 1.7 167.6
V dither 1x5 180 4.7 23.5 191.1
I single image 2 1.7 1.7 192.8
I dither 1x3 180 4.7 14.1 206.9
------------------------------------------------------
1. Exp is the exposure time for each image in seconds.
2. Exp+readout is the exposure plus 1.7min readout time for each image.
3. Total is the total time ((Exp+readout) x dither) for each filter.
4. Timeline is the accumulated time for each field.
Under Frame:
A. single image: take one short exposure for each filter. No dither.
B. dither 1x5: Use command "mosdither" to do one set of standard dither pattern
of 5 positions for R, Ha and V filters. Take one image at each position.
The standard dither pattern is at "ditherdb$todd.dat".
It looks like this:
===========
# Tod Lauer's canned dither scheme for the NOAO mosaic
# Offset relative to current telescope position
# RA (pixels) Dec (pixels)
0 0
160 -240
-160 240
80 120
-80 -120
==============
C. dither 1x3: Use command "mosdither" to do one set of dither pattern of 3
positions for I filter. Take one image at each position.
Create and use a "ditherdb$dither3.dat" file like this:
===========
# Dither 3 positions.
# Offset relative to current telescope position
# RA (pixels) Dec (pixels)
0 0
160 -240
-160 240
===========
OR, simply use the standard dither pattern and stop it after 3 exposures.
If there is enough time, please take standard dither (1x5) for I filter as well.
A. Since the first target of each night has lower priority than the second and third targets, please don't spend more than 207 min (3h27m) on the first targets. Otherwise it will shorten the observing time for higher priority targets in later night. Please move to the second target by 10:46PM each night at the latest. If it's necessary, shorten the time for the first targets as suggested in item B in order start the second targets by that time.
B. When time is running short, do the following to save time:
a. First reduce the number of V images to dither 1x3. (save 9.4 min)
b. Skip V and I short (2 sec) images. (save 1.7 min each)
c. Reduce the number of I deep images, then V deep images. (save 4.7 min each) But keep at least one V and one I images.
When take only one deep V and one deep I images, the total time needed for a field is reduced to 175.3 min - a total saving of 31.6 min.
C. Try to start 10-15 min before and end 10-15 after the astronomical twilight zone to get a little more observing time. D. Don't need to take the standard (not enough time). We will apply for time on smaller telescopes for the calibration later.Night Do ------------------------------------------------------ 5/13 RCW38 Wang_GC1 Wang_GC2 5/14 MYCN18 Wang_GC3 Wang_GC4 5/15 CENX-3 Wang_GC5 Wang_GC6 5/16 G292.2-0.5 MARS XTEJ1723-376 5/17 MSH11-62 1RXSJ161411.3 GALACTICPLANE ------------------------------------------------------
postscript and
txt
Here is an observing almanac made for this run. Download it here and print it out.
Take skyflats in the evening or morning twilight if possible. Because we are looking at the galactic disk, it's impossible to construct skyflats from object frames. I filter skyflats are probably the most needed in order to correct the fringes.
THANKS!
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