Tempel 1 and Deep Impact

Observed: 3, 5 July 2005

Michel Bonnardeau
6 July 2005

Abstract

39 h after the collision, the comet was still slightly brighter than before.

Introduction

The NASA probe Deep Impact reached Tempel 1, releasing its 370kg Impactor that collided with the comet on July 4, 2005 at 05:52 UT at 10.2km/s. The energy of the collision was 19 GJ (the equivalent of 4.8 tons of TNT), the comet was at 0.89 au from Earth, see http://deepimpact.jpl.nasa.gov/home/index.html.

Observations

I observed the comet with a 203mm f/6.3 SC telescope, a SBIG ST7E camera (KAF401E CCD) and a Clear filter. Each exposure is 1 mn long.

Observation 8.3h before the collision:

For my location, it was daylight at the time of the collision. The night that followed, it was raining. So I observed it 39.4h after the collision:

The comet appeared to be slightly brighter after the collision. More precisely, I measured the following intensities (in ADU) from stacked images (4x60 s exposure):

BEFORE:	intensity=126,160	background=2829
AFTER:	intensity=167,624	backgroung=2801

Technical notes

Telescope and camera configuration.

Software and computer configuration.