There are thousands of new asteroids discovered
each year. Many of them are
Near Earth Objects (NEOs),
small bodies which fly relatively close to the Earth.
Because they are so small,
they are detectable only for a few days or weeks before
receding into invisibility.
During their brief first appearance, we need as many
observations as possible to make even a rough estimate
of their orbit; when they come around for the next pass,
even one or two measurements can pin down their orbital
parameters well enough to predict their motion for
a decade or more.
That can be important, because some NEOs may eventually
collide with the Earth.
Some NEOs are as bright as tenth or eleventh magnitude,
but they tend to move so quickly through the sky that
they may be trailed on long exposures.
Determine the rotation period of an asteroid
We know surprisingly little about the great majority of asteroids
in our solar system. For example, we have measured the rotation
periods of only a few hundred.
You can find a list of known (and unknown) properties of the brighter
Note the "reliability code" in this table.
Note also the large number of asteroids which do not appear --
that means their rotational properties are completely unknown.
A good place to go for more information, and for hints on
good targets, is
Depending on the particular asteroid chosen, this project
would probably require 10-20 hours of measurements
spread over 3-5 nights.
Measure the period of a variable star
Many stars vary in brightness, for several reasons:
due to eclipses in a binary star system,
or pulsations in the stellar atmosphere,
or the motion of dark spots as a star rotates,
Measuring the exact period and amplitude of a
star's light curve -- at several different wavelengths --
can provide the evidence we need to figure out many
physical properties of the star, such as size, mass,
There are a number of groups which study variable stars:
Use processing techniques to sidestep the atmosphere
In recent years, good video cameras have become cheap.
They can detect only very bright objects, but the major
planets in the Solar System are bright. People have worked
out ways to improve the quality of pictures by
combining many short exposures in sophisticated ways.
You can find one very simple example, involving our own
There are lots and lots and LOTS of web sites which describe
how one can process large stacks of images.
These sites will describe the software, such as
you need to do the job.
A few examples are
Aside from making very pretty pictures, these techniques
can tell us about the weather on other planets -- Mars
Observe an occultation (by asteroid or moon)
Once or twice a month, the shadow of an asteroid passes over
Rochester. If we can measure the exact time when it happens,
and the duration of the dimming of the background star,
we can pin down the orbit of the asteroid, place strong
limits on the size of the asteroid, and maybe even
learn something about the star. We have done this quite
often in Rochester; see, for example,
The Moon also passes in front of stars occasionally,
which can tell us about the topography of the very limb of
the Moon, and sometimes information about the occulted star.
You can find predictions of upcoming events, plus information
on what to do, at
Detect a planet around another star
several ways to detect planets around other stars.
One of them involves transits, in which the
planet passes in front of its star and blocks a tiny fraction
of the starlight for a few hours.
With careful processing, even small telescopes can
detect these transits.
Spectroscopy of stars and nebulae
Spectra of celestial objects can provide much more information
on their physical nature than simple images.
However, acquiring spectra takes more effort than
taking a picture;
analyzing the result takes more work, too.
Copyright © Michael Richmond.
This work is licensed under a Creative Commons License.