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SN Observing

Instructions for observing the SN fields during SV, including additional observations to reach depth desired in ugrizY for photo-z training.

Note: SN reduction software expects pointings to be aligned at 10" or so accuracy, else major headaches result. As of 10/26, Blanco pointing model is not sufficiently accurate for this. So observers will need to slew to each field and take a small exposure; then look at one CCD's images to determine an offset to bring telescope to within few arcsec of the nominal pointing. There should be printouts placed in console room marking nominal positions of stars on a reference CCD. This short initial exposure after slew will also allow the AOS (donut) system to bring the telescope into proper focus for remaining exposures.

Coordinates and Exposure Times Per SN Visit

Exposures in this table constitute 1 SN visit. During SV we will want to complete 1 visit in good seeing + photometric conditions to establish templates, plus one additional visit to attempt subtraction & detections.

Field Name Base RA Base Dec No x Time of Exposures Done?
g r i z Template Search
E1 7.8744 (00:31:29.9) -43.0096 (-43:00:34.6) 1 x 175s 1 x 150 s 1 x 200s 2 x 200s griz Nov 2 griz Nov 7 + griz Nov 21
E2 9.5000 (00:38:00.0) -43.9980 (-43:59:52.8) 1 x 175s 1 x 150 s 1 x 200s 2 x 200s griz Nov 11 griz Nov 8 + griz Nov 23
S1 42.8200 (02:51:16.8) 0.0000 (00:00:00.0) 1 x 175s 1 x 150 s 1 x 200s 2 x 200s griz Nov 7
S2 41.1944 (02:44:46.7) -0.9884 (-00:59:18.2) 1 x 175s 1 x 150 s 1 x 200s 2 x 200s griz Nov 7 griz Nov 11
C1 54.2743 (03:37:05.8) -27.1116 (-27:06:41.8) 1 x 175s 1 x 150 s 1 x 200s 2 x 200s griz Nov 7
C2 54.2743 (03:37:05.8) -29.0884 (-29:05:18.2) 1 x 175s 1 x 150 s 1 x 200s 2 x 200s griz Nov 7
C3 52.6484 (03:30:35.6) -28.1000 (-28:06:00.0) 3 x 200s 3 x 400 s 5 x 360s 11 x 330s i Nov 22 + z Nov 23 g Nov 10, gr Nov 12 (e=0.2-0.3)
X1 34.4440 (02:17:46.6) -4.6000 (-04:36:00.0) 1 x 175s 1 x 150 s 1 x 200s 2 x 200s move field 18 Nov griz Nov 9
X2 35.4471 (02:21:47.3) -6.2474 (-06:14:50.6) 1 x 175s 1 x 150 s 1 x 200s 2 x 200s move field 18 Nov griz Nov 9
New X1 34.4757 (02:17:54.2) -4.9295 (-04:55:46.2) 1 x 175s 1 x 150 s 1 x 200s 2 x 200s
New X2 35.6645 (02:22:39.5) -6.4121 (-06:24:43.6) 1 x 175s 1 x 150 s 1 x 200s 2 x 200s
X3 36.4500 (02:25:48.0) -4.6000 (-04:36:00.0) 3 x 200s 3 x 400 s 5 x 360s 11 x 330s gri Nov 18 + z Nov 19 gr Nov 6 + i Nov 8 + i Nov 12 + i Nov 13 + z Nov 15 (e=0.3)

Extended SV DiffIm Processing at FNAL

Process Date Night Field Name Bands Processed? Stamps copied? Template Notes
Dec 2 SN-C1 griz yes   yes Nov 7 reprocessed with convolve new
Dec 2 SN-C2 griz partial failure yes Nov 7
Dec 2 SN-C3 iz   this is the template - will not process
Dec 2 SN-E1 griz yes yes
Dec 2 SN-E2 griz yes yes
Dec 2 SN-S1 griz template is from 10/29 - will not process
Dec 2 SN-S2 griz yes yes processed with convolve new
Dec 2 SN-X1 griz this is the template - will not process
Dec 2 SN-X2 griz this is the template - will not process
Dec 3 SN-X3 iz yes yes i Nov 18, z Nov 19 convolve new. fakeMatch failed on z_46.
Dec 4 SN-C1 griz yes yes Nov 7 convolve new. fakeMatch failed on i_45
Dec 4 SN-C2 griz partial failure yes Nov 7 convolve new. db stopped mid-run. gr: complete. iz: many failures.
Dec 4 SN-C3 griz no template for gr, could process iz, but only 2 day span
Dec 4 SN-S1 griz template is from 10/29 - will not process
Dec 4 SN-X3 gr   partial failure yes gr Nov 6
Dec 11 Dec 5 SN-X3 z yes yes z Nov 19 convolve new
Dec 11 - 12 Dec 5 SN-X1 griz yes yes Dec 2 Using diffim devel. Fake placement failed. convolve new, even though I meant not to
Dec 12 Dec 5 SN-X2 griz yes yes Dec 2 Using diffim devel. Change search radius in filterObj 0.0005 --> 0.0003 deg convolve new, even though I meant not to
Dec 5 SN-E1 griz --- will skip for now
Dec 5 SN-E2 griz --- will skip for now
Dec 13 Dec 6 SN-C1 griz yes yes Nov 7 using convolve new
Dec 14 Dec 6 SN-C2 griz yes yes Dec 2 using diffim v2.7 using convolve ref.
Dec 14 Dec 9 SN-S1 griz yes yes Dec 2 using diffim v2.7 using convolve ref.
Dec 14 - 15 Dec 9 SN-S2 griz yes yes Dec 2 using diffim v2.7 using convolve ref.
Dec 15 Dec 9 SN-X1 griz yes yes Dec 2 using diffim v2.7 using convolve ref.
Dec 15 Dec 9 SN-X2 griz yes yes Dec 2 using diffim v2.7 using convolve ref.
Dec 15 Dec 9 SN-C1 griz yes yes Dec 2 using diffim v2.7 using convolve ref.
Dec 15 - 16 Dec 9 SN-C2 griz yes yes Dec 2 using diffim v2.7 using convolve ref.
Dec 16 Dec 9 SN-E1 griz yes Dec 2 using diffim v2.7 using convolve ref.

Dither Pattern for SN Visits

SNWG requests that dithers for a given filter cycle through 3-position pattern A-B-C with offsets from above nominal positions given by:

Position Offset
A 0" W, 0" N
B 1.7" W, 4.7" N
C 4.7" W, 1.7" N

For the shallow fields all exposures of a visit are taken in position A with the exception of the second z band exposure which is taken in position B. For the deep fields (C3, X3) for each filter we cycle through these positions. For example, the 5 i band exposures in the X3 field are taken at positions A-B-C-A-B

Additional Exposures to Reach Photo-z Depth

Each of these sequences need be done only once, in photometric conditions, with not-terrible seeing (<1.3" ??). Observers should select dithers of <10" between exposures.

Dataset Fields Additional Exposures Done?
SNu E1,E2,S1,S2,C1,C2,X1,X2 2 x 120s u E1, E2, X1, X2 (Nov 10), C1, C2 (Nov 12), S1, S2 (Nov 13)
SNY E1,E2,S1,S2,C1,C2,X1,X2 2 x 50s Y E1, E2, X1, X2 (Nov 10), C1,C2 (Nov 12), S1, S2 (Nov 13)
VVDSu C3,X3 3 x 300s u X3 (Nov 10), C3 (Nov 12)
VVDSgY C3,X3 1 x 200s g + 5 x 100s Y X3 (Nov 10), C3 (Nov 12)

Scripts and Special Instructions

Separate scripts are available for each of the 8 shallow fields. For the deep fields we have individual scripts for each filter.
For the template measurements early in the SV period we prepared special scripts for each of the shallow fields that separates the iz and gr observations.
Did you read the note on top of this page? Because of the issues with the telescope pointing precision and the needs of the F&A system you have to take a separate exposure before you start a SN script. All of the scripts below assume that the telescope is in position. i.e. each script's first exposure is wherever the telescope is currently pointing.

SN Field Script
E1 DES/sv_sn_e1_griz.json
DES/sv_sn_e1_iz.json
DES/sv_sn_e1_gr.json
E2 DES/sv_sn_e2_griz.json
DES/sv_sn_e2_iz.json
DES/sv_sn_e2_gr.json
S1 DES/sv_sn_s1_griz.json
DES/sv_sn_s1_iz.json
DES/sv_sn_s1_gr.json
S2 DES/sv_sn_s2_griz.json
DES/sv_sn_s2_iz.json
DES/sv_sn_s2_gr.json
C1 DES/sv_sn_c1_griz.json
DES/sv_sn_c1_iz.json
DES/sv_sn_c1_gr.json
C2 DES/sv_sn_c2_griz.json
DES/sv_sn_c2_iz.json
DES/sv_sn_c2_gr.json
C3 DES/sv_sn_c3_g.json
DES/sv_sn_c3_r.json
DES/sv_sn_c3_i.json
DES/sv_sn_c3_z.json
X1 DES/sv_sn_x1_griz.json
DES/sv_sn_x1_iz.json
DES/sv_sn_x1_gr.json
X2 DES/sv_sn_x2_griz.json
DES/sv_sn_x2_iz.json
DES/sv_sn_x2_gr.json
X3 DES/sv_sn_x3_g.json
DES/sv_sn_x3_r.json
DES/sv_sn_x3_i.json
DES/sv_sn_x3_z.json

Special scripts to reach photo-z depth:

SN Field Script
E1 DES/sv_sn_e1_u.json
DES/sv_sn_e1_Y.json
E2 DES/sv_sn_e2_u.json
DES/sv_sn_e2_Y.json
S1 DES/sv_sn_s1_u.json
DES/sv_sn_s1_Y.json
S2 DES/sv_sn_s2_u.json
DES/sv_sn_s2_Y.json
C1 DES/sv_sn_c1_u.json
DES/sv_sn_c1_Y.json
C2 DES/sv_sn_c2_u.json
DES/sv_sn_c2_Y.json
C3 DES/sv_sn_c3_VVDSu.json
DES/sv_sn_c3_VVDSgY.json
X1 DES/sv_sn_x1_u.json
DES/sv_sn_x1_Y.json
X2 DES/sv_sn_x2_u.json
DES/sv_sn_x2_Y.json
X3 DES/sv_sn_x3_VVDSu.json
DES/sv_sn_x3_VVDSgY.json