Productive night

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Pete
Astro Day Coordinator
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Joined: Fri Jun 13, 2003 9:03 pm

Productive night

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Log of Saturday, October 20, 2012

This log is written on Oct 29th, very much after the fact. Sometimes I get behind on documentation :oops: Got started late, well after darkness fell. Air temp 59F.

329338 is a 1.0 km sized Apollo now 17.6 mag and .12 AU distant. Uncertainty level is 1 and RMS residual is 0.51, with apparent motion at 7.9’/hr. Imaged from 20:22 – 20:36 hrs at 30 sec, 2X2, -19C, 2 Hz. Using track & stack, frames 1-3, 6-8 & 11-13 show dRA = -0.1’ & dDEC = +1.1’ Upon subsequent review at time of documenting with this log, it is noted that the first group showed an anomaly, with dRA = -0.9’ So I made an error somewhere, even if it was simply transcribing data for the log.

2002 UA31is a 1.0 km sized Aten now .24AU distant and 17.8 mag. Uncertainty level 3, RMS residual is 0.49 Movement is 5.3’/hr. Imaged from 20:46 – 21:10 hrs at 1 min, 2X2, -19C, 3 Hz. Frames 1-3, 4-6 & 8-10 show dRA = 0.4’ and dDEC = +0.2’

2012 TZ52 is a 500 meter sized Amor now 18.6 mag and .18 AU distant. Uncertainty level is 6 and RMS is 0.45 Imaged from 21:16 – 21:50 hrs at 1 min, 2X2, -20C, 1 Hz. Stars very blurred. And the guide star is only 12th magnitude. Ouch! Discovered severe dew buildup on corrector plate. The observatory hair dryer was applied. Stacks of images 1-5, 6-10 & 11-15 show dRA = +0.5’ and dDEC = 0, with faint diffuse images associated with the dew.

2008 HV4 is an 830 m sized Amor now 18.6 mag and .32 AU distant. Uncertainty level is 3, RMS is 0.46”, and motion is 2.1’/hr. Imaged from 22:09 – 22:27 hrs at 2 min, 2X2, -20C, 5 Hz. Got it weakly in single frames, but since stacking provides a more robust solution, images 1-2, 3-4 & 5-6 are stacked to show dRA = +0.4’ and dDEC = +0.3’.

17182 is a 2.4 km sized Apollo now .8 AU distant and 18.7 magnitude. Uncertainty is 2, RMS is 0.49”, and motion is 1.4’/hr. Imaged from 22:432 – 23:16 hrs, details recorded in observatory computer data but not noted on the worksheet that forms the basis of this log. There’s a second asteroid in the images. Both are bright in individual frames. Frames 1, 4 & 7 show dRA = +0.32’ and dDEC = +0.1’

2012 SW58 is a 19.0 magnitude asteroid moving thru the 17182 frames at a slow .52’/hr. Uncertainty level is 3. Frames 1, 5 & 10 show dRA & DEC = +0.1’

2005 SH19 is a 2.5 km sized asteroid .9 AU distant and 19.0 magnitude. Uncertainty level is 2, and motion is 2.3’/hr. Imaged from 23:32 – 23:53 hrs at 2 min, 2X2, -20C, 2 Hz. The dew has cleared and we now have sky conditions normally only occurring in mid-winter. I’ve got the 19.0 mag asteroid in single 2-minute frames! But weak. Stacking for a more robust solution, frames 1-2, 3-4 & 5-6 show dRA & dDEC = +0.1’

2012 QF48 is a 2.5 km sized asteroid chosen as a quick and easy last target for the night. I’m tired, but at 14.8 magnitude this one’s easy to fit in. Distance is .2 AU, motion is 5.7’/hr, uncertainty level is 2. Imaged from 00:03 – 00:12 hrs at 30 sec, 2X2, -20C, 25 Hz. It’s amazing how fast the AO can be run when guiding on a 7th mag star! Images 1, 3 & 5 show dRA = +0.6’ and dDEC = +0.2’. S/N averages around 33:1, and FWHM around 4.5, so magnitude measurements of 15.0 (red) are also included in the MPC data.


Conclusions & lessons learned.

The anomaly noted on the first observation seems to be part of a pattern where I’m getting sloppy. Usually my mistakes seem to be with the final processing of the MPC reports, and that can be attributed to tiredness, but to not pick up bad data that stands out from the rest….

Dew problems are very rare in a dome, but they do happen 2 or 3 times in the fall. It’s been a while and as noted above I wasn’t particularly alert this evening.

The ST-8XME is particularly sensitive in the red, so when S/N climbs above 30 I figure that I’m probably good to ±0.1 magnitude in the R filter band.

8 asteroids with 24 observations submitted to the MPC is a pretty good night’s run.

hgp logged noon, 29 Oct 2012
Pete P.
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