Starship Asterisk*

Venus and Mercury in the West

Explanation: In this twilight skyview, a windmill stands in silent witness to a lovely pairing of planets in the west. The picture was recorded on April 5 from Gallegos del Campo, Zamora, Spain. Venus (left) and Mercury (right) are near their much anticpated conjunction in the early evening sky. But even in the coming days, these two evening stars will remain close in the western sky at sunset. In fact, with brighter Venus as a marker, sky watchers will have an excellent guide for spotting Mercury nearby, a planet often hidden in the Sun's glare.

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Why not have a link available on facebook? So out facebook page gets the picture of the day uploaded daily.

In your April 7, 2010 APOD, you refer to Mars and Venus as Evening Stars. I know this is a time honored tag for each but why not call a planet a planet and a star a star? Thanks, a daily APOD reader.

In answer to the facebook question, please see our previously related discussion of this:
http://asterisk.apod.com/vie ... =9&t=18030 .
That said, if anyone would like to help out create, and maintain an APOD Facebook presence, please contact me.

- RJN

Pray tell that our language continues to allow for poetic lavishing, especially onto celestial objects which so often cannot be adequately nouned by the simple and normal that adorns so many a well meaning conscious.

johnhami@bellsouth.net wrote:In your April 7, 2010 APOD, you refer to Mars and Venus as Evening Stars. I know this is a time honored tag for each but why not call a planet a planet and a star a star? Thanks, a daily APOD reader.

In my English dictionary, there are at least two definitions of star that are perfectly consistent with this usage. That is, depending on context, it is perfectly correct to call a planet a star. Even when the image is astronomical in nature, the terminology may still be reasonable. This image is more about aesthetics than it is about the underlying astronomy; the use of some poetic language (time honored, as you say) is rather appropriate, I think.

Moments like shown in this image are good for picturing the motion of Venus and Mercury in real life context, which I sometimes have a hard time doing. If I am not mistaken the velocities at this moment of each planet are pointed sort of downwards with a "toward the viewer" component as well--between the Earth and the sun of course. These give a different "feel" than ones that go around the Earth's orbit. I give credit to all early pioneers who figured this out by observation.

hstarbuck wrote:Moments like shown in this image are good for picturing the motion of Venus and Mercury in real life context, which I sometimes have a hard time doing. If I am not mistaken the velocities at this moment of each planet are pointed sort of downwards with a "toward the viewer" component as well--between the Earth and the sun of course. These give a different "feel" than ones that go around the Earth's orbit. I give credit to all early pioneers who figured this out by observation.

Both planets are moving "upwards" right now- they are moving eastwards with respect to the stars, and getting higher in the sky (farther from the Sun). Mercury is about to turn around and start heading towards the Sun again, but Venus will continue getting higher all (northern) summer, and not start heading back towards the Sun until August 20.

Chris Peterson wrote: Both planets are moving "upwards" right now- they are moving eastwards with respect to the stars, and getting higher in the sky (farther from the Sun). Mercury is about to turn around and start heading towards the Sun again, but Venus will continue getting higher all (northern) summer, and not start heading back towards the Sun until August 20.

Thanks Chris. After posting I drew it out and realized that by the picture alone it could either be up, out of the screen, or down. I guess one would have to look this info up or observe at the same time each night. As they go down, they are closer and therefore larger right? Tricky.

I clicked on one of the links from the APOD and found a diagram with explanation relevant to my above posts. http://www.skyandtelescope.com/observin ... 79827.html.