5391 Emmons

Notes, Observations and Images

WCAC Special Achievement Award - Presented to Dick Emmons

August and September of 2002 marked the opposition of a little, obscure asteroid.  Whoopee - right?  But this particular asteroid is designated 5391 Emmons, and was named by its discoverer Dr. Elanor Helin in honor of our friend and fellow member Dick Emmons.  We featured Dick's "pet rock" as he likes to call it at our August meeting.  Thanks to Dave Gill for the program on solar system evolution and asteroids. The club presented Dick with a life time achievement award. We tried to find and image Dick's "Pet Rock" with no luck that night.

Below are some articles and Images of "Dick's Pet Rock"
(use your browser back button to return)

The Rock Hounds, By Dave Gill. A tail of searching and finding 5391 Emmons.

5391 Emmons - Asteroid named after WCAC member Dick Emmons. A story by Dave Gill with ephemeris tabulated and plotted.

"Asteroid Named after N. Canton Astronomer", The Canton Rep - (http://www.cantonrep.com) in their July 4, 2000 printing.

"Stark Astronomer's Namesake Rock Approaches", The Canton Rep - (http://www.cantonrep.com) in their September 3, 2002 printing.

Kent Stater 9/11/02 article on Dick Emmons and Emmons 5391 from the Kent State University paper.

5391 Emmons images.

John Waechter took a series of images during The Wilderness Center's public viewing night (approximately 1am) with the STV camera on the Resetar 10" LX200 SCT telescope at f/3.3 over a 1 hour period resulting in the following images. (Use your browser's back button to return.) It was also viewed by all there, including the guest of honor Dick Emmons, through the Resetar/STV on a 25 inch monitor. It was viewed by all there visually with and without the image intensified eyepiece (AKA Dick's kidney) in the 16 inch Keller and Dave Gill's 14 inch dob.

Image 5391_090602_1.jpg (3KB)
Image 5391_090602_2.jpg (8KB)
Image 5391_090602_3.jpg (5KB)

From Maurice Clark. A set of 3 images that were obtained of asteroid 5391Emmons. These were obtained arround UT 07:32 September 4, 2002. 5391 is towards the top of the images. There is a second asteroid to the lower right of the centre. This is the asteroid 1999 TV15 (18056). Also-managed to get 3 night's worth of images of 5391. From an analysis of the photometry, it appears that the rotation period is about 3.226 hours, which is quite fast. The total variation in brightness is about 0.25 magnitudes. I have attached a copy of the light curve. (Use your browser's back button to return.)

Image 5391A.gif (409KB)
Image 5391B.gif (348KB)
Image 5391C.gif (366KB)
5391_animation_maurice_clark.ppt (920KB) Power Point animation
Image 5391lightcurve.gif (7KB)

Additional info from Maurice: The images were 3-minute exposures using an ST-8E binned 2x2 and an 8" f/10 LX200 at prime focus. They were taken at Goodsell Observatory, which is on the campus of Carleton college, Northfield Minnesota. By the way, I did another night on 5391 and have derived a better looking lightcurve. Still a bit more noisy than I would have liked but not too bad. Including this extra night gives a period of 3.028 hours and an amplitude of 0.14 mag. I have attached a copy of the new lightcurve. I hope Prof Emmons was interested to learn how fast his pet rock was rotating.

Image 5391lightcurveb.gif (11KB) (Use your browser's back button to return.)
Maurice Clark's Website - Great astronomy pics and stuff. (Close the new window to return.)

John Waechter and Bill Castro spent Sunday eve/Monday morning (9/1-9/2) at The Wilderness Center observatory to chase down and image Dick's "Pet Rock".  Luck was on our side for a change, the skies remained clear all night. We finally found our elusive target.   We took a series of images with the STV camera on the Resetar 10" LX200 SCT telescope at f/3.3 over a 2 hour period resulting in the following images. (Use your browser's back button to return.)

Image 5391-02.jpg:  (44KB) 5:05 UT  -  20 second exposure.
Image 5391-06.jpg:  (44KB) 6:05 UT  -  30 second exposure.
Image 5391-10.jpg:  (50KB) 7:07 UT  -  25 second exposure.
Image 5391-08.jpg:  (42KB) 6:39 UT  -  25 second exposure.  (Suspected geostationary satellite moved through the frame during this last exposure.  Previous frame had streak from lower right of image to the point where this one starts.) Approximate field of view for all images is 26' wide x 15' high.  The faintest star in the triangle of stars at the left side of the frame is magnitude 15.4.  I see the asteroid as being just slightly fainter...WOW!

Custom finder charts and ephemeredes for 5391 Emmons

 Date__(UT)__HR:MN R.A._(a-app)  DEC_(a-app)
 2002-Aug-30 04:00  23 19 58.56 -03 42 26.7
 2002-Aug-31 04:00  23 19 10.85 -03 44 14.6
 2002-Sep-01 04:00  23 18 22.27 -03 46 08.4
 2002-Sep-02 04:00  23 17 32.91 -03 48 07.6
 2002-Sep-03 04:00  23 16 42.89 -03 50 11.7
 2002-Sep-04 04:00  23 15 52.31 -03 52 20.1
 2002-Sep-05 04:00  23 15 01.30 -03 54 32.4

| emmons_eph.xls | Chart 1 | Chart 2 | Chart 3 | Chart 4 | Chart 5 |

| Chart 6 | Chart 7 | Chart 8 | Chart 9 | Chart 10 |

Back to WCAC Home Page

| Current Stories/News | Past Meetings | Past Special Events | Past Horizon Newsletters |

Last updated March 25, 2005 by Bill Castro