Deep Impact Mission Small Telescope Science Program

In another thread "Spacecraft to slam comet?", it was stated with
respect to the Deep Impact mission, which will crash an kinetic
impactor into a comet at 10.2 km/s during July 5, 2004:

Chris L Peterson wrote in message . ..
On Thu, 21 Oct 2004 17:00:45 -0700, "
wrote:
snip Wouldn't this possibly change the orbit of the comet, which can
then
either hit Eearth or even hit other comets and change their course? snip

The energy will be enough to make a 100m crater in a 6km diameter object. The
momentum of an object a microscopic fraction of the mass of the comet will be
transferred to the comet. I very much doubt that the resulting orbital
deviation is even measurable. It certainly won't be enough to throw
the comet into an Earth crossing orbit. snip

This prior thread prompted me to do some further reading, particularly
as I could not easily find any estimate of the mass of Comet 9P/Tempel
1 in common references or via NASA ADS. I contacted the public
affairs officer at the Deep Impact Mission team at the University of
Maryland, who relayed the following answer from the mission team:

=========================
"We don't know the mass of comet Tempel 1 at this time. We don't even
know its size very accurately yet. We can estimate its mass by
assuming a density and dividing the Density by the volume and compute
a mass. M=D/V. Our best estimate is anywhere from 0.1 - 2.5 x 10 exp
14 kg.

We should be able to constrain this value better after we analyze
images of the impact and have a more accurate shape model of the
comet. The goal of the Deep Impact mission is to determine the
composition and structure of the interior of the comet. We will arrive
at a more accurate value of the mass in the process."
=========================

That's a mass estimate range for Comet 9P/Tempel 1 of between:

10,000,000,000,000 kilograms and
250,000,000,000,000 kilogram.

In contrast, the Deep Impact Mission homepage recites the mass of the
kinetic impactor as:

370kg - 820 lbs
http://deepimpact.umd.edu/science/cratering.html

Traveling at 10 km/s, the 370kg impactor spacecraft will obviously
have a significantly greater effective mass - but still relatively
insignificant when compared to the low-bound mass estimate of the
comet. Another Deep Impact Mission webpage describes a TNT equivalency
resulting from kinetic impactor's collision:

=========================
"When an impactor strikes a target, it has a great deal of kinetic
energy (proportional to the object's mass and the square of its
velocity). For example, the impactor spacecraft for the Deep Impact
Mission has a mass of 370 kg, and will be traveling at a velocity of
10.2 km/s. This means its kinetic energy will be 19 gigajoules (GJ),
which is about the equivalent of the amount of energy released by
exploding 4.8 tons of TNT, or about the amount of energy used in an
average American house in one month."
=========================
http://deepimpact.umd.edu/science/cratering.html

I'd have to agree with Chris's characterization that there should not
be any general public concern that the impact and resulting kinetic
explosion would cause any orbital deviation in Comet 9P/Tempel 1.

The purpose of the mission is to study the unknown chemical
composition of comets with spectroscopy on the impacts ejecta and the
structure of a comet from the resulting shape of the impact crater.
See -

http://deepimpact.umd.edu/science/objectives.html
and
http://deepimpact.umd.edu/science/cospar-ms.pdf

The Deep Impact mission's website also solicits participation in an
observing program by advanced amateurs with high-end CCD gear and V
and R band filters. The following is an excerpt from the Deep Mission
Impact amateur astronomer program website at -

http://deepimpact.astro.umd.edu/stsp/
and at
http://deepimpact.astro.umd.edu/stsp.../index05.shtml

regarding equipment requirements:

=========================
"Telescope Requirements

Minimum apertu 9.5 inches or 24 centimeters

Suggested focal length: f/4 or f/5, but more important is to match the
CCD's pixel resolution to the seeing and to the telescope's image size
while retaining a large field of view!

CCD Requirements

One of the top-notch, commercial CCDs such as:
Apogee
HiSIS
SBIG
Meade

Pixel resolution of 2 arcseconds or better.

Filter Requirements

Use standard photometric filters (Kron-Cousins, Johnson, Bessell) V
and R to make observations of the comet. These filters allow us to do
scientifically meaningful studies of Comet 9P/Tempel 1. If your system
has an infrared cutoff filter, it must be removed when you observe
with photometric, broadband, V and R filters! If you do not have these
types of filters, do not lose hope! You have some options: . . . .

=========================

The purpose of the small telescope observing program is described in
Deep Impact Small Telescope Science Program webpage as:

=========================
"The main objective of the program is to provide continuous monitoring
of 9P to complement data acquired at large telescopes. Many observers
who control their own observing time can contribute to our goal for
continuous coverage. The program is interested in receiving
photometric quality, broadband R, CCD images of 9P as well as
spectroscopic observations. These data will help scientists understand
and model the activity and dust environment of the comet before,
during, and after the mission excavates a crater in the nucleus in
early July 2005."
=========================

Looks like this presents a great opportunity for participants in this
forum to put their expensive gear to use.

I would be interested in hearing any descriptions, observing reports
and updates from any amateurs here who are participating in the Deep
Impact Mission small telescope observing program.

For those just interesting in following the comet between now and July
2005, the Deep Impact mission also publishes useful observing guides
and ephemeredes at -

http://deepimpact.astro.umd.edu/amat...ts/index.shtml

- Canopus

(Canopus) wrote in message . com...
In another thread "Spacecraft to slam comet?", it was stated with
respect to the Deep Impact mission, which will crash an kinetic
impactor into a comet at 10.2 km/s during _July 5, 2004_:
snip-all

To correct my prior post, the date of Deep Impact encounter is July 5,
2005, not 2004 as previously stated.

Current best estimate of the resulting impact carter are that it will
only be 200 meters in diameter and 20 meters deep.

http://deepimpact.umd.edu/science/cratering.html
http://deepimpact.umd.edu/science/cospar-ms.pdf

Will it be possible to see the impact ejecta from earth? See 1983
comet sketch made by an observer in 1983 using a 10" scope:

http://deepimpact.umd.edu/gallery/drawings-83jun.html

- Canopus