Chandra Deep Field IMACS Observation Masks Ranked in the order of priority, i.e. number of slit on the mask. N Mask Mask# RA Dec Slit Hole Mag.range obs obx ps SMF FC ------------------------------------------------------------------------------------------ 1 cdfs1 4198 03:32:28.000 -27:47:55.00 110 4 14.5-21.9 obs obx ps SMF FC 2 a1332 4204 01:03:38.400 -21:42:00.00 76 5 16.8-21.6 obs obx ps SMF FC 3 smc2 4201 00:55:24.000 -72:33:00.00 71 4 14.4-21.3 obs obx ps SMF FC 4 a1331 4202 01:02:02.400 -22:06:16.69 68 4 14.3-21.4 obs obx ps SMF FC 5 smc3 4203 00:50:24.000 -72:51:00.00 66 6 13.9-21.5 obs obx ps SMF FC 6 smc1 4199 00:50:24.000 -73:15:00.00 64 8 14.4-21.0 obs obx ps SMF FC 7 cdfs2 4200 03:32:49.735 -27:52:31.90 57 4 17.2-21.5 obs obx ps SMF FC 8 a1333 4206 01:03:40.800 -22:06:00.00 54 8 14.6-21.5 obs obx ps SMF FC 9 smc5 4205 01:03:48.000 -72:05:24.00 51 6 13.8-21.6 obs obx ps SMF FC 10 a851 4207 00:41:48.000 -09:20:24.00 41 10 13.7-21.7 obs obx ps SMF FC 11 smc4 4208 00:46:48.000 -73:06:00.00 38 8 13.8-21.3 obs obx ps SMF FC 12 fornax1 4209 03:38:24.287 -35:26:21.36 32 4 14.2-21.7 obs obx ps SMF FC ------------------------------------------------------------------------------------------ N: Rank of priority. Mask: Mask name. Mask#: Mask number. RA,Dec: RA, Dec (J2000) of the center of the mask. Slit: Number of object slit on the mask. Hole: Number of alignment star hole on the mask. Mag.range: Magnitude range of objects on the mask. Maskfiles: obs, obx, ps SMF FC: Finding chart of 1X1 degree.
Astronomical twilight on 9/25: 20:59 - 06:09, duration 9h10m
1. smc is observable all night.
2. a85 and a133 are observable one hour after the start of the astronomical twilight.
3. cdfs and fornax are observable three hours after the start of the astronomical twilight.
Here is the Las Campanas Observatory
2021 Ephemeris.
1. On 9/25-27, the astronomical twilight durations are 9h10m, 9h8m, 9h6m, respectively.
2. There are 12 masks. Aim to observe 4 masks per night. Spend average 2h17m on each mask, including the overhead time.
3. Always start the night with one of the smc masks, since only smc is observable at the beginning of the night.
4. It's best to observe cdfs and fornax after midnight for lower airmass.
Here is the observation plan based on the above consideration and their ranking:
Night Date mask1 (#) mask2 (#) mask3 (#) mask4 (#) ---------------------------------------------------------------------- 1 9/25 smc2 (4201) smc3 (4203) smc1 (4199) cdfs1 (4198) 2 9/26 smc5 (4205) a1332 (4204) a1331 (4202) cdfs2 (4200) 3 9/27 smc4 (4208) a1333 (4206) a851 (4207) fornax1 (4209) ----------------------------------------------------------------------O. Take the standard bias, flat, dark, etc in the afternoon.