Astronomy 104
Spring 2025,
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.

ANNOUNCEMENTS
TEST 1 is coming up on Friday, Feb. 21.

Quiz and lab grades have been posted on Feb. 15.


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 Activity  is in full swing now, lots of sunspots.
Click for today's look.


 Last Quarter: Feb. 20,  New Moon: Feb. 27,
  First Quarter: Mar. 6, Full Moon: Mar. 14.
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Planets:

Venus  is up for a short time after at sunset.
 Mars 
rises at sunset,
Jupiter
is up all night.

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News

1. An asteroid has a ~1% chance to hit Earth in 2032.
2. Red Novae are merging stars!
  3. New models of the NASA's DART impact reshaping the asteroid moon Dimorphos show that this object is 'rubble all the way down'.
4.
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 .

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Unusual events and objects

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