Astronomy 104
Fall 2022,
Sections 1 through 8.

These are introductory courses to astronomy, with more emphasis on active thinking than memorizing facts. The main points of this course are (1) a general understanding of astronomy, (2) what can be observed in the sky, (3) the Solar System in 103 / the stars and the Universe in 104.


Students must have a scantron (#16485) and a pencil (no pen) for each class.
(This adds up to ~25 scantrons for the whole semester.)

What's up in the sky?

Solar Cycle 25 has just started, more and more sunspots are appearing.
Click for today's look.

  New Moon: Oct. 25.  First Quarter: Nov. 1,
Full Moon: Nov. 8, Last Quarter: Nov. 16.

Saturn is up all night,  Jupiter  rises at 8pm, both are visible at late night.
(7.8mg)  is next to Jupiter in the sky.
Asteroids: Vesta (5.8mg) is close to Saturn, Juno (8.4mg) is close to Jupiter in the sky.



1. The DART mission smashed into asteroid Dimorphos. See the pictures here and here. It successfully changed the asteroids orbit.
. Look at some great images taken by the James Webb infrared space telescope.
One of the stars we observe in the labs (during the winter), eta Geminorum, is orbited by two companion stars, one of which is surrounded by a recently discovered disk of dust.
4. The TESS satellite has found ~ 5000 exoplanet candidates, out of which 175 have been definitely confirmed.


Unusual events and objects

(Students might want to ask help in how to use the coordinates, ephemerids and finder charts.)