Venus in the Morning
Published on Oct 31, 2007 at 10:55 am.
3 Comments.
Filed under skywatching.
If you get up a little before dawn and look to the East, you can’t help seeing an extremely bright object in the sky. That is the planet Venus. There is no way to miss it (unless a tree or building is in the way!).
Venus outshines anything else in the sky except the Sun and Moon. In fact, Venus is so bright that it has often been mistaken for a UFO. Venus has a synodic period of about 384 days. That is about 1.6 years. So, that means that you’ll see Venus in the mornings every 1.6 years. However, Venus appears to move along the ecliptic, like the other planets. The ecliptic, however, makes a different angle with respect to the horizon at different times of the year. Right now, the ecliptic is very steep relative to the horizon for observers in the northern hemisphere, and it makes a shallow angle relative to the horizon for observers in the southern hemisphere. That means that Venus is much higher in the sky just before dawn for us in the northern hemisphere than it is for observers down under. But, one synodic period later, Venus will be high in the morning sky along a different portion of the ecliptic. Then, Venus will be highest for observers in the southern hemisphere instead of for us in the northern hemisphere. All this taken together means that Venus is best viewed in the mornings about every three years or so. This year it is best for us in the northern hemisphere. It will be about three years until it is best for us in the mornings again, and it was just over three years ago that it was similarly best for us in the mornings. So, with such a long time between similar viewings, non-astronomy minded people tend to forget. Now, granted, Venus was very well placed for viewing this past summer in the evenings, but a lot of non-astronomers seem to have a disconnect from what is seen in the evening to what is seen in the morning. In fact, in ancient times people had different names for the very bright “morning star” and the very bright “evening star,” both of which were the planet Venus! The Greeks called the morning star Eosphorus (or Phosphorus) and the evening star Hesperus.
But, Venus is not alone in the morning sky this year. Above Venus are two other “stars.” The upper one, is in fact, a star. It is the star Regulus, in the constellation Leo. Regulus is sometimes called Cor Leonis (the heart of the lion).
Between Regulus and Venus is another “star,” except that this is no star. It is actually the planet Saturn. So, you can see two naked eye planets near each other in the morning skies. Go out and take a look. If you keep going out every few mornings, you’ll also notice that Venus and Saturn are getting farther away from each other. Venus was at its farthest distance from the Sun in the sky just a few days ago, and is now a bit lower in the sky each day. Due to the motion of the Earth around the Sun, though, Saturn is a bit higher in the sky each day at the same time.
-Astroprof
(Sky view produced using Stellarium)
Burzycki.org - Tech and Interesting Facts on November 2, 2007 at 12:14 am: 1
[…] Astrosphere for October 31st, 2007 October 31st, 2007 | Category: Contributors, Astronomy Happy Halloween everyone. First up, enjoy a triple view of Comet Holmes, captured by ngc3314. Of course, Halloween is an excuse to write spooky flavoured press releases. Here’s one from NASA’s Cassini mission about the spooky sounds of the Saturnian system. And this chilling tale of a meteorite… IT Came From Vesta. Astronomy Picture of the Day focuses on the “Ghost Head Nebula”. Cosmic Log’s Alan Boyle looks at the science of spooks. And finally, Phil Plait has a terrifying image of, of… well, you’ll just have to see for yourself. Thomas Marquart from Apparent Brightness suggests a trick you can use to pare down your RSS feeds to just get the ones you want. I actually do this to just focus on space-related news. Have you noticed a bright star in the mornings? That’s not a star, that’s Venus. Centauri Dreams reconsiders Gliese 581. It’s looking less and less Earthlike every day. […]
Robert on November 3, 2007 at 9:04 am: 2
I have always noticed Venus in the morning ,thanks for the info. My Grandfather always made referance to Venus in his poetry.
Astronomically Hopeless on November 11, 2007 at 6:39 pm: 3
yea I wish I were that observant. You know I need it for a journal I’m working on in science class. Oh boy…