On Monday night, Feb 22, 1999, I braved the cold (it was about 10 degrees Fahrenheit!) to search for asteroid 4 Vesta.
One member of the RIT Astronomy Club joined me at the start of the night. We turned briefly to the first-quarter moon, which displayed a wealth of detail along the terminator. The 16-inch telescope plus 15-mm eyepiece provided a very nice view of a big valley running through a mountain range. When we tried a 10-mm eyepiece, though, the image was a bit too fuzzy for my taste.
At around 8:35 PM, I was left alone, and turned to the task of finding Vesta. I tried using the Orion Short-tube telescope (80 mm aperture, 400 mm focal length), which yields a field of view of about 1 degree with the Meade Pictor CCD camera. I made up several charts at different scales, which proved very handy. The combination of 5-degree- and 1-degree-wide charts allowed me to identify the field quickly, and after about 5 minutes I was able to take pictures of Vesta and several nearby stars.
I continued taking pictures every 10 minutes or so for about 90 minutes. Below are two pictures, one taken at 9:04 PM and one at 10:37 PM. North is up and east to the left. Can you find the moving object?
Vesta is the brightest object in the field. It saturated the CCD in these 15-second exposures, taken without any filter. Perhaps it will be easier to see its motion in these closeups:
Vesta moved
up (north) about 1.1 pixels = 10 arcsec
right (west) about 5.3 pixels = 49 arcsec
from 9:04 PM to 10:37 PM. That corresponds to about 32 arcseconds
of motion each hour.
The very large field of view of the Orion 80-mm telescope
makes finding objects a breeze ... but, on the other hand,
it makes the motion of a typical asteroid hard to detect
over the course of an hour or two.
It might be better to take pictures through our 10-inch
Meade telescope for future asteroid work.
The faintest stars visible in these images are about fourteenth magnitude.