David's Astronomy Pages
Images - Session 606 (2012-12-12)

Objects Session Notes
Bullet (4179) Toutatis Flyby - Minor Planet / PHA
 
Bullet Photometric Monitoring - Variables
- U And, W And, Z And, TT Ari, S Cyg, SS Cyg, U Gem, BL Lac, FO Ori, FU Ori, NV Ori, DY Per, GK Per, RR Tau

- RX And & CI Cyg attempts failed (due to cloud)

   
Bullet Astrometric Monitoring - Nearby Stars
- None
- Late Evening session (4.0 hrs duration). 
Moderate seeing
- Session operated under semi-automated control, with remote monitoring from indoors computer.  
- Ambient Temperature: -5.0°C (minimum)
- CCD operation -30°C (at 58% average cooling).  
- main objectives of the session were to acquire images of selected project stars for ongoing photometric and astrometric analysis, opportunity was taken to acquire a series f images of the PHA 4179 Toutatis during its 2012 flyby of earth at ~ 18 lunar distances. 
-

(4179) Toutatis Flyby - Minor Planet / PHA

(4179) Toutatis Flyby

Discovered in 1989,  4179 Toutatis is a potentially hazardous asteroid (PHA) that passes by Earth’s orbit every 4 years.  
At closest approach on 12th Dec 2012 the tumbling space rock passed earth at some 18 lunar distances (7 million km)

Measuring 4.5 km in length, Toutatis is one of the largest known PHAs, and its orbit is inclined less 
than half-a-degree from Earth's.  No other kilometer-sized PHA moves around the Sun in an orbit so nearly coplanar with our own. 
This makes it an important target for astronomical radar studies.
NASA's Goldstone radar in the Mojave Desert was trained on the the space rock every day from Dec. 4th through 22nd. 
The echoes highlight the asteroid's topography and improve the precision with which researchers know the asteroid's orbit.
Radar imagery of asteroid Toutatis taken by NASA's Goldstone Solar System Radar on Dec. 12 and 13 
 More :  http://echo.jpl.nasa.gov/asteroids/Toutatis2012/Toutatis2012_planning.html 

The next time Toutatis will approach at least this close to Earth is in November 2069, when the asteroid will safely fly by at 
about 7.7 lunar distances (3 million kilometers). Scientists calculate that there is zero probability 
of the asteroid hitting earth over the entire interval over which its motion can be accurately computed, which is some 400 years.
 http://science.nasa.gov/science-news/science-at-nasa/2012/12dec_toutatis/ 

 

Opportunity was taken to acquire a series of CCD images of Toutatis through my LX200 telescope during part of the flyby.

(4179) Toutatis - Moving rapidly through starfield in Pisces
Image below is an average of 116 frames, each of 10s exposure.  
This image stacking highlights background stars but makes the asteroid appear much dimmer than it really was. 

Image

Annotated CCD Image
116 x 10s exposure (average combine), 3x3 binning, C Filter 
2012-12-13 00:36 to 01:21 hUT (#532245-360)
12" LX200R  (at f/9.7) + ST-10XME

 

Image below shows the maximum pixel values from 116 frames.  This image shows the asteroid with the correct
relative brightness but means that only the brightest background stars can be seen.
Asteroid has apparent magnitude of +10.7, compared to a magnitude of +9.2 for the brightest star in the image (SAO 110141)

Image

CCD Image (maximum value of 116 frames)
Image details as above

Motion of  (4179) Toutatis 

Image

CCD Image Animation 
(10 frames taken from full set of 116 frames)
Image details as above

 

(4179) Toutatis 

Image

Annotated CCD Image (cropped)
10s exposure (single frame), 3x3 binning, C Filter 
2012-12-13 01:00 hUT (#532305)
12" LX200R  (at f/9.7) + ST-10XME

Back to Top