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Category Archives: 04. Observing the stars and planets: clockwork of the Universe

Millions of people across Indonesia and the Central Pacific have witnessed a total solar eclipse. Because the eclipse path crossed the International Date Line, in the local time zones it began early on Wednesday, March 9, and ended late on Tuesday, March 8.




The Cosmos author, Jay M. Pasachoff, shares his view of totality from the south side of Ternate, in the Maluku Islands of eastern Indonesia:

“All the eclipse phenomena were visible: diamond ring, Baily’s beads, prominences (with a particularly bright prominence at the 9 o’clock position) and the corona, but through thin clouds.”


Credit: Jay M. Pasachoff

Different views of the eclipse provided the Astronomy Picture of the Day (APOD) on March 10, 11, and 12: wide angle view, looking down from NASA’s DISCOVR satellite, and a low-resolution flash spectrum.


Here is a consolidated list of errors from the text’s first printing. Many of these have already been posted here as separate chapter updates. (Our publisher will make the necessary corrections to the printed book at the earliest opportunity.):

p. 25, Figure It Out 2.3: The last paragraph (about Fraunhofer) shouldn’t be there. Instead, it should be at the end of the caption of Figure 2-4 on p. 26.

p. 64, Q34: 1 Angstrom should be listed as 1010 m, not 108 m.

p. 64, Q41: Ditto

p. 78: There is an error in the equation relating the apparent magnitude and brightness of stars in Figure It Out 4.1.  In this equation, 2.512 should be raised to a power equal to (mB−mA).

p. 92, Q1: We could more clearly say “On the top picture” instead of just “On the picture” – since there are now two pictures on the opening page of the chapter (and the stars are somewhat too dense for individual clarity in the bottom picture).

p. 190: First sentence of Section 7.4d: “a little larger” should be “a little smaller” for the relative sizes of Triton and the Moon.

p. 309, Q53, there is a printing error when going from the bottom of column 1 to the top of column 2. At the top of column 2, the “(e)” should be boldface, there should be a period after “1/16”, and the remainder of the text should be deleted.

p. 363, column 1, second line from the bottom: When referring to the event horizon: “1/3” should be “2/3”, i.e. the sentence should read “Its radius is exactly 2/3 times that of the photon sphere…”

p. 391, column 2, second line from the bottom: for Spitzer, “Section 3.8c, Figure 3-32a).” should say simply “Section 3.8c).”

p. 392, column 1, line 5: At the end, add “(See Section 3.8c, Figure 3-32a.)”

Appendix 3C, column 3 header: “105 km” should be “106 km”

A total lunar eclipse will be visible throughout the continental United States on the night of Monday April 14-Tuesday April 15, 2014.  Eclipses of the Sun and of the Moon are discussed in Section 4.2, starting on p. 70.

Lunar eclipse

Credit: Michael Zeiler,

An animation showing the visibility of the eclipse and all relevant times may be seen here:
It was made by Michael Zeiler (; Mr. Zeiler accompanied author Jay M. Pasachoff on the expedition to observe the total solar eclipse of November 2013 from Gabon in Africa.

The opening partial phase of the eclipse begins about 2 a.m. Eastern Daylight Time, with the total eclipse lasting from about 3:07 am to 4:25 am EDT.  The closing partial phase of the eclipse ends at 5:33 am EDT, and will be visible from most of the U.S. and Canada but not from the East Coast.  In Pacific Daylight Time, the eclipse is 11 pm partial/12:07-1:25 am totality/-2:33 end.

The Astronomy Picture of the Day (APOD) on March 17, 2014, shows warped star trails over Arches National Park, in Utah, USA.

Credit and copyright: Vincent Brady

The warping effect occurs because the picture is actually a full 360 degree panorama, horizontally compressed to fit your screen. As the Earth rotates, stars appear to circle both the North Celestial Pole, on the left, and the South Celestial Pole, just below the horizon on the right. While the eye-catching texture of ancient layered sandstone covers the image foreground, twenty-meter tall Delicate Arch is visible on the far right, and the distant arch of our Milky Way Galaxy and its dark dust lanes may be seen near the image center.

Credit: Vincent Brady

There is an error in the equation in the right-hand column relating the apparent magnitude and brightness of stars. In this equation, 2.512 should be raised to a power equal to (mB–mA), not merely multiplied by it. The formula should read:

bA = 2.512(mB-mA) × bB

This movie, called “Death Valley Dreamlapse” illustrates the apparent movements of the celestial sphere (caused by Earth’s own rotation) during the course of the night, as  (see Figure 4-19). See if you can identify what might be planes, satellites and meteors!

Credits: hosted by the LA Times. Shot and edited by Gavin Heffernan. Produced by Sunchaser Pictures.