A really productive night for astrometry

User avatar
Pete
Astro Day Coordinator
Posts: 3230
Joined: Fri Jun 13, 2003 9:03 pm

A really productive night for astrometry

Unread post by Pete » Fri Nov 18, 2016 6:08 pm

Thursday, 17 Nov 2016

Suddenly it’s getting dark surprisingly early. Planned on running flats at twilight but without haze or cloud the sky darkened early enough to run some good 1/5 second flats with just the tee shirt frame at around 16:20 The camera’s dried out and there’s no frost at a modest -15°C

On Sunday night the operation was debugged. Tonight’s objective is to go with the flow doing astrometry on near-Earth asteroids. It’s wonderfully clear at 17:30, with no dewfall and excellent seeing. Temperature’s a relatively warm 48°F

2016 PX66 is a 953-meter sized Amor presently 19.1 magnitude and 0.3 AU distant. Discovered 89 days ago, uncertainty level is still 3. Apparent motion is 2.5’/hr. Imaged from 17:45 – 18:05 at 2 minute exposure, 2X2 binning, -15C cooling, 5 Hz guiding and full reduction (bias, dark frame, flat frame, separate dark frame for flat). It’s visible in single frames but stacking provides a higher S/N and I’ve got the time. Frames 1-2, 3-4 & 5-6 show ∆RA = +0.2’ and ∆Dec = +0.1’

2016 SD is a 1.1 km sized Apollo now 19.0 mag and .33 AU distant. Discovered 109 days ago, uncertainty level is 3. Apparent motion is 0.7’/hr. Using track ‘n stack, frames 1-2, 3-4 & 5-6 show ∆RA = 1.0’ and ∆Dec = +0.7’. S/N is high at 8.6:1 and FWHM tight at 3.1” so my numbers are good and this guy’s not exactly where it was thought to be.

2016 ON is a 952 meter sized Amor now a dim 19.5 mag and .43 AU distant. Discovered 107 days ago, uncertainty level is 3. Motion is 2’/hr. Scope refocused. Imaged from 18:53-19:10 at 150 sec, 2X2, -15C, 3 Hz. There are no bright stars in this image so all frames are noisy even with full reduction. Frames 1-2, 3-4 & 5-6 show ∆RA and ∆Dec = +0.3’ S/N = 7.5 and FWHM = 4.0”

It’s still “warm” at 47°F 

2016 QD is a 1.0 km sized Amor now 18.7 mag and .4 AU distant. Orbital arc is 88 days so uncertainty level is 3. Motion is 0.8’/hr. Imaged from 19:27 – 19:47 at 150 sec, 2X2, -15C, 3 Hz. Frames 1-2, 3-4 & 5-6 show ∆RA = 0 and ∆Dec = +0.1’

2016 VZ3 is a relatively small 315 meter sized Amor now 18.2 mag and .12 AU distant. Orbital arc is just 36 days so uncertainty level is 7. This is a fast mover: 13.3’/hr. Imaged from 19:54 – 20:20 at 23 second exposure, 2X2, -15C, 10 Hz. Autodark was used for this oddball exposure rather than setting up a full reduction. Frames 2-11, 16-25 & 31-44 show ∆RA = -0.5’ and ∆Dec = +0.3’ With stacking S/N = 19:1 and FWHM = 4.2’

This is the end of my planned session. But I’m not particularly tired and it’s still 46°F so I’ll keep going on this lovely calm transparent night – even though an 80% phase waning moon is hidden below my neighbor’s roof line.

2016 UN36 is a small 115 meter sized Amor now a dim 19.5 mag and a close 7 million miles. Orbital arc is just 18 days and uncertainty level is 6. Motion is 2.5’/hr. Imaged from 20:37 – 21:01 at 2 min, 2X2, -15C, 2 Hz. Frames 1-3, 4-6 & 7-9 show ∆RA = +0.7’ and ∆Dec = +0.3’ S/N = 4.5 and FWHM = 5.0”

2016 UC57 is another small (120-meter) Amor now a dim 19.5 mag. It’s relatively close at 10 million miles distant and relatively fast at 4’/hr. The speed necessitates deep stacking of short exposures – if I’m to be successful at all in capturing this guy. Discovered just 12 days ago, uncertainty level is 7. Imaged at 1 min, 2X2, -15C, 2 Hz from 21:19 – 22:16 hrs. Getting chilled so ducked into the house to warm up and work this one remotely. There are 3 other relatively bright asteroids in the image field, and they’re worked first. Fortunately the plate solve is working and saving me a lot of effort here. There are stars in the way but eventually frames 10-19, 30 – 39 & 40 – 49 show ∆RA = 0 and ∆Dec = +1.5’. Asteroid images are all fuzzy and faint. The 1st set is very poor at S/N of 3.9/1 and FWHM of 9.0” and the last set has improved to 7.1/1 and 4.9”, but position numbers are consistent and UC57 is indeed a bit off from the calculated ephemeris.

1999 JX7 is a 4.6 km sized asteroid in the 2016 UC57 frame. It’s 17.0 mag, .8 AU distant and surprisingly has an uncertainty level of 1. Motion is 1.2’/hr. Frames 10, 15 & 20 show ∆RA = -0.1’ and ∆Dec = 0 S/N = 15 and FWHM = 4.0”

6680 is a 13.8 km sized asteroid in the 2016 UC57 frame. It’s a bright15.5 mag and 1 AU distant. Uncertainty level is 0. Motion is 41”/hr. Frames 10, 18 & 27 show ∆RA = -0.1’ and ∆Dec = 0 S/N = 40 and FWHM = 3.6”

67773 is a 7.2 km sized asteroid in the 2016 UC57 frame. It’s a 18.4 mag and 1.7 AU distant. Uncertainty level is 0. Motion is 40”/hr. Frames 10-12, 20-23 & 30-32 show both ∆RA and ∆Dec = 0 S/N = 12 and FWHM = 4.0”

6534 Carrie Peterson is now above the elm tree in the east. First time it's been visible all year. Tonight this 20.8 main belt asteroid is 17.0 magnitude and 2.0 AU distant. Motion is 29”/hr. The 80% waning moon is perhaps15° behind 6534 tonight so there’s a bit of reflection in the optics. Feeling tired & chilled so working from indoors. Imaged from 22:36 – 23:11 at 3 min, 2X2, -15C, 2 Hz. Frames 1, 5 & 9 show ∆RA and ∆Dec = 0 S/N = 19 and FWHM = 4.2”
Image

Observatory closed up at 23:15 and 33 observations forwarded to the MPC by 23:30.

Conclusions & observations:

Wow! This is probably a new record for the number of observations. Didn’t expect anything like this, but the sky was so perfect I couldn’t restrain myself.

hgp logged 17:32 hrs, 18 November 2016
Pete P.
User avatar
Apollo XX
MSSF Coordinator
Posts: 2448
Joined: Sun Jul 11, 2010 8:11 pm

Re: A really productive night for astrometry

Unread post by Apollo XX » Sat Nov 19, 2016 4:35 pm

Congrats on your great night Pete! There's never a dull moment out there, is there?
Mike M.
User avatar
DonB
Posts: 459
Joined: Thu Apr 04, 2013 6:16 pm

Re: A really productive night for astrometry

Unread post by DonB » Sat Nov 19, 2016 9:59 pm

Yes, Pete, that sounds like a super night. Thanks for sharing. 8) 8) 8)


Don
"When I was 18, my father was the dumbest man I ever knew.
When I was 21, I could not believe how much he had learned in 3 years."
--- Mark Twain

Orion 120mm F/5 Refractor
Celestron 8
Explore Scientific 80 Triplet
Explore Scientific 102 Triplet
Orion 8" Astrograph
User avatar
AndyG
Network Admin
Posts: 1160
Joined: Wed Nov 30, 2011 10:18 pm

Re: A really productive night for astrometry

Unread post by AndyG » Sat Nov 19, 2016 10:06 pm

Yes, interesting report, and I like how you posted the image of 6534 CARRIE PETERSON.
Andy
Locked