Date: 2021 Apr 16 UTC LBTO Observer: Olga Kuhn (LBTO) Lead Partner Observer: Charlotte Wood (ND) Other Partner Observers: Peter Garnavich (ND), Rick Pogge (OSU, at start) Telescope Operator: Steve Allanson (LBTO) Special Assistants: Bentlye Moon phase: 4d before first quarter Summary: Program was to be MODS plus LBC, but not a very productive night due to clouds. ND_LRGCGM/J0948 was observed, but through variable extinction which hovered around 2 mags and reached ~3 mags at times, so a loss. Spectra of two OSU_ASASSN/ELL targets, ELL2 and ELL4, were obtained so the night was not a total loss. Calibrations: none Completed Programs: None, only observations of a poor-condition band 3 program could be done due to conditions Details (All times UT): ---------------------------------- 01:53 Sunset Configured for MODS 02:32 Steve has checked/corrected pointing and the telescope is collimated on a star near the target (Feige 34) Flux Star Feige34 02:41 acquired Fiege 34 02:45 12-deg twilight 02:58 started observations 03:16 18-deg twilight ND_LRGCGM/J0948 We updated the POSANGLE to be -46 deg (314 deg) which will be about the midpoint of the 1-hr observation, including about 15-min for acq. 03:18 acquired target J0948 The object looks pretty well-centered in the 0.6" slit, but a tad to the right on both MODS1 and 2. Since the clouds are coming, we are just going to start observing. Clouds are coming as we are acquiring. The guide signal was dipping by up to 2 mags. 03:31 starting science observations seeing 0.9-1 arcsec At the end of the 1st exposure, the guide star flux was down by 3 mags! We see faint traces on MODS2 B and R and on MODS1 B and R, but unsure that anything useful will come of it. 04:22 sky camera image during third exposure shows clouds coming through, partial clearing near the end. OSU_ASASSN/ELL4 Brighter targets (band 3) that could work with 1-2 mag of clouds 04:42 acquired ELL4 We checked th parallactic angle at about 20-min from now (10-min for acq and 10-m to the mid-way point of the observation), but it is -56, very close to the -54 in the UT0730 acq script. The guide star (only available one) is R=16, it is guiding and WFSing currently so we are crossing our fingers. 05:00 start of observing, seeing ~1.3 arcsec NOTE: The exposure time of 60-sec may saturate in for clear conditions (saturation). OSU_ASSASN/ELL2 05:24 acqBinoMODS ELL2_UT0530.acq Changed the POSANGLE to -115 deg to match the parallactic angle about 20-min from now. The guide star has R=14. No star found. Steve checked the pointing and confirmed it was good. Edited the script to use POSANGLE 65 for which there is a R=12.99 guide star useful given the clouds 05:30 acqBinoMODS ELL2_UT0530_180.acq seeing about 1.2/1.4-arcsec during the acquisition. 05:42 started science observing, seeing 1.3-1.5 arcsec 06:30 lost guiding briefly OSU_ASASSN/ELL5 06:07 acquired wtih UT0830 script which has a closer mid-exp parallactic angle. No guide star found, clouds getting heavier. Tried for a brighter guide star, but conditions deteriorated rapidly and had to abort. 06:25 closed due to cloud Even the bright ELL targets cannot be done because the guide stars are just a bit too faint for these conditions and the other targets would not stand this much extinction. 09:50 We are still closed for clouds. 11:00 Steve is closing up. We're only 20 minutes from 18-deg twilight and the sky is still covered with clouds. 11:22 18-deg twilight 11:53 12-deg twilight 12:45 Sunrise