A Quick Look At 1 Ceres

Is it a giant asteroid? Is it a dwarf planet? Is there a difference?

1 Ceres has been classified as both. Ceres is the largest object in the Asteroid Belt between Mars and Jupiter – something like 900 km across. We will get our first really good look at it in about 2 years when NASA’s Dawn spacecraft arrives in its orbit. It was in fact the first “asteroid” discovered, in 1801. It ranges from magnitude 7 to 9, so is almost never visible to the unaided eye, but it’s also pretty easy to find with most telescopes.

I thought I’d take a look using the University of Iowa’s Rigel telescope in Arizona, using the web-based Sierra Stars Observatory Network. Here’s a shot of 1 Ceres captured during the night of 1 May 2013. Ceres is the bright “star” in the middle of the frame. It’s so bright (around magnitude 8) that it’s actually quite overexposed on this cropped image. The image here was made by stacking three 150 second exposures.

2_112103_3 ceres cr1 800px

The dwarf planet 1 Ceres photographed early on the morning of 1 May 2013 using the University of Iowa Rigel Telescope in Arizona. Ceres is the brightest object in this image, in the centre of the frame. It’s so bright compared to the many background stars that it’s actually over-exposed here. A composite of three stacked 150 second exposures without filters taken with the 31 cm robotic telescope, over the Sierra Stars Observatory Network.

The particulars from the FITS file of the first of three images taken by Rigel:
DATE-OBS= '2013-05-01T03:25:00.311' / UTC, start of exposure
LST     = '10:39:31'           / Local sidereal time at exposure start
POSANGLE= '  70:48:39'         / Position angle, degrees, +W
LATITUDE= ' 31:39:56'          / Site Latitude, degrees +N
LONGITUD= '-110:36:05'         / Site Longitude, degrees +E
ELEVATIO= ' 38:22:26'          / Degrees above horizon
AZIMUTH = '283:31:10'          / Degrees E of N
OBJRA   = '  6:39:18.3'        / Target center J2000 RA
OBJDEC  = ' 28:48:59.6'        / Target center J2000 Dec


Copyright © 2013 David Allan Galbraith