AXIS Observing Report +++++++++++++++++++++ INT WFC imaging: December 15,16,17 2000 Observers: Tim Roberts, Nick Schurch (Leicester) Instrument: standard WFC imaging at INT prime focus Filters: U g r i Z Ha Exposure (dark time): 1200s 600s 600s 1200s 1200s 1200s Exposure (bright time): N/A N/A N/A 2400s 2400s 2400s Pointing position: ------------------ 2.5 arcmin RA, 2 arcmin dec offsets from XMM field position as advised Observing conditions: --------------------- 15 Dec: Terrible. Dome not opened due to 100% humidity 16 Dec: Dome not opened until 4.30am due to continuation of previous night's weather. Data taken for 1h 45mins until more cloud appeared. Seeing poor, at only ~ 2 - 4 arcsec. 17 Dec: Weather conditions near perfect. Seeing at ~ 1 arcsec all night. Time lost to technical problems: -------------------------------- Some problems on last night with mirror "wobble" (symptoms: regular "knocking" sound (every ~2 seconds), guide star blurred along 1 axis). Fixed by moving telescope to zenith and then back to target. Had to do this 4 or 5 times in last night, losing ~ 30 mins in total. Targets observed ---------------- (In chronological order) Date Target Filters Comments 16/12 s5 0836+716 i b; n; poor seeing " *MS1137.5+6625 i b; n; poor seeing; observation stopped 2/3 way through due to re-emergence of clouds 17/12 *G133-69 pos 2 U " HT Cas g Ha G " *HCG 16 U " A 189 U g i Z " *PHL 1092 U " A 478 offset U g r i Z n " A0620-00 i Ha b; G; n " *MS0737.9+7441 i b; n " *GRB001025 Ha b; G " *PG0844+349 i b; n " *Cl0939+472 i b; n * XMM observations already made + XMM observations scheduled b Bright time (moon up) G low Galactic latitude field n new imaging target Bright time: ------------ This run was unfortunately scheduled with the with the moon up and positioned between 9h - 12h in the second half of all three nights. This meant that even if we'd had good weather we couldn't have observed a number of new XMM fields at 10h - 12h, all potentially good XID fields for follow-up in the next few months. We therefore concentrated on getting i-band imaging on fields in the 6h - 9h range, most of which have XMM data, in bright time. Dark time: ---------- Since dark time was only available early in the night, it didn't make sense to go purely for new fields to follow-up spectroscopically since the fields at this range of RA will soon dip below the horizon. Hence we decided to finish off fields with outstanding filters that could be done in dark time, e.g U-band. Biases/Flat fields/Landolt standards: ------------------------------ A set of 5 biases were taken before the start of observing each day. Flat fields were only taken at the beginning and end of night 3 due to weather conditions. Landolt standards were taken at the beginning of our observing window on night 2, and at the beginning, middle and end of night 3. Exposure times for the standards varied somewhat; this was due to conflicting advice from our TO, SS and previous runs. Summary ------- In effect, we only had 1 and a bit nights out of 3. In this time we completed the filter sets for 6 fields, and began or continued the filter sets for 7 more. All 13 fields now have i-band imaging, and 8 of these fields already have XMM data. Tim Roberts 20 Dec 2000