Friday, October 3, 2008

Mercury on Oct 6th

Borrowed this from Astronomy Newsletter / Astronomy Magazine

On October 6, Mercury passes between the Sun and Earth in a configuration known as inferior conjunction. That same day, NASA's MESSENGER spacecraft flies past the innermost planet for the second time this year. After inferior conjunction, Mercury moves west of the Sun and becomes visible in the morning sky within 10 days. By that time, hundreds of MESSENGER images should have been returned to Earth, many showing regions of the planet never seen before.

On October 16, Mercury lies 8° above the eastern horizon 30 minutes before sunrise and shines brightly at magnitude 0.5. The key to good views of Mercury is its angular distance from the Sun. All else being equal, the greater this distance, the sooner the planet rises before our star (or the later it sets, in the case of evening apparitions).

Mercury reaches greatest elongation October 22, when it stands 18° west of the Sun. This isn't the largest angular distance Mercury can achieve. The planet passed through perihelion, the closest point in its orbital path around the Sun, just 5 days earlier. Nevertheless, Mercury stands 5° high in the east an hour before sunrise October 22 and climbs another 6° in the next 30 minutes. It shines a full magnitude brighter than it did a week before and will be easy to find.

On October 16, a telescope reveals the inner planet's 8"-diameter disk, which appears 27 percent lit. As the planet heads toward greatest western elongation, its disk shrinks and the illumination increases. By the 22nd, the globe appears 7" across and 55 percent sunlit. Mercury lingers through October's final week, when it will be easiest to see as it continues to brighten.

On October 31, Mercury shines at magnitude -0.9. It lies 8° above the eastern horizon 30 minutes before sunrise. It also lies 4° north of Spica, the brightest star in Virgo the Maiden, that morning. Through a telescope, Mercury's disk is then 83 percent illuminated and 6" across.

To find more observable objects in your sky, visit's sky events calender.

Terri, Events Coordinator
Phoenix Astronomical Society

Thursday, October 2, 2008

North Mountain Park VISITOR CENTER Star Party - Change of Date!!!

Good morning TEAM,

I just realized that somehow Allyson and I got the dates crossed for this star party
and instead of it being on this Saturday it is TOMORROW Friday... Yipes.
If you can still volunteer for Friday, that would be awesome.

Allyson has 35-40 RSVP's,
and we had 5 telescopes ready for Friday night.

The time will be the same... 6pm to 9:30pm but on Friday 10/3.

I didn't realize she had scheduled it different than what we had discussed.
So, please make a note of it. I'll move it in the calendar today,
so look for the info on Friday, tomorrow's date.

With a crowd like we have, I'd like to have more volunteers.

Terri, Events Coordinator
Phoenix Astronomical Society

Wednesday, October 1, 2008

Do We Live In a Giant Cosmic Bubble?

Received this link from William


Terri, Events Coordinator
Phoenix Astronomical Society

Star Date update on 5 planets

Stargazing Summary
stargazing iconOf the five planets visible to the unaided eye, three are lurking in the shadowy realms of twilight this month. Venus is just climbing into visibility as the “evening star” in the southwest shortly after sunset, while Mars disappears below it. Mercury puts in a meager performance in the morning twilight. Saturn is pulling out of the dawn glow, but is pretty low in the east at first light. Only Jupiter sallies boldly forth, shining in the south at nightfall. Taurus, the bull, is starting to charge into evening skies, while the aquatic constellations that form the celestial sea drift across the south and east.
October Sky Almanac:
Weekly Stargazing Tips:

SkyTips is a publication of the University of Texas McDonald Observatory Education and Outreach Office, 1 University Station A2100, Austin, TX 78712. Reproduction of SkyTips content is permitted with proper credit given to McDonald Observatory.

Terri, Events Coordinator
Phoenix Astronomical Society