jump to navigation

USPS Star Calendar for 4-10 September 28 August 2011

Posted by amedalen in September 2011.
Tags: , , , , , , ,
trackback

4 Sep    Antares is 4 finger-widths to the moon’s lower right tonight. First-quarter moon at 1739 UT

5 Sep    Tonight, the waxing gibbous moon is between Sagittarius and Scorpius in the south.

6 Sep    Sagittarius is to the moon’s lower right tonight. About two-thirds of the moon’s surface is illuminated.

8 Sep    Magnitude 0.9 Altair is the bright star 2.5 fist-widths above the moon tonight.

9 Sep    Mercury and Regulus rise nearly 1.5 hours before the sun. Magnitude 0.9 Mercury is 0.67 degrees (less than half the width of your index finger held at arm’s length) to the left of magnitude 1.4 Regulus. This is the year’s closest planet-first magnitude star appulse.

Advertisements

Comments»

1. george Prescott - 2 September 2011

Please explain “This is the year’s closest planet-first magnitude star appulse.” Appulse is not in my dictionary! George Prescott, SN

2. P/C Arnold Medalen, S/N - 2 September 2011

George

Thank you for your question. Appulse is an astronomical term meaning the close approach of two celestial bodies as seen from the earth. It is noteworthy when we have the closest appulse for the year of a planet and a first magnitude star.

In this case the planet is magnitude 0.9 Mercury and the first magnitude star is magnitude 1.4 Regulus. Since they rise less than 1 ½ hours before the sun you will need a clear view of the eastern horizon to see them. Slightly brighter Mercury will be to the left and they will be separated by about 2/3 of a degree. This is less than one-half the width of your index finger, held at arm’s length. They will rise about 1 fist-width above the horizon before the sky brightens and they are lost in the morning light.


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: