28 November 2010

Brilliant Venus and Old Moon in the Dawn Sky

With sunrise at 7:00 in the morning, I find this time of year to be one in which I can do some early morning stargazing without having to change my morning routine. This week the waning Moon provides a lovely scene against the backdrop of brilliant Venus, bright Saturn and the bright star Spica. The illustration demonstrates what to expect in the eastern skies as the Moon shrinks each day on its way to the New Moon on December 5th. If you are a morning person with an interest in astronomy, this will be an excellent week for you. Get out your binoculars for an especially riveting view of these heavenly bodies, and take in a few minutes of beauty about an hour before the sunrise.

22 November 2010

Review of iPhone Astronomy Apps: ISS Visibility and Iridium Flares

Two of my favorite iPhone apps are ISS Visibility and Iridium Flares, apps that help you to locate satellites very precisely. I use these two apps extensively, anytime I have clear skies and want to enjoy the spectacle of dazzling satellites crossing the sky, even here in the bright city lights of San Francisco. Continuing from my previous post on iPhone apps, here are two more reviews.

ISS Visibility does exactly what it promises by telling you when and where to look to see the International Space Station. Transits of the ISS across the evening or morning sky are impressive, whether the viewing is of the space station crossing a broad arc across the sky, or a short appearance that ends in the impressive flickering and fade of the ISS as it crosses the Earth's shadowline from daylight to night. At a price of $1.99, ISS Visibility gives you simple-to-use charts based on your location, and shows you where to look along with a nice 2D map showing the location of the ISS over Earth as it passes your viewing site.

Iridium Flares are bright lights in the sky that shine when Iridium Satellites in orbit around Earth reflect sunlight back toward the planet and produce a particularly bright glint of light in the sky for a few seconds. I find iridium flares wonderful to watch because at their best they flare up to -7 or -8 magnitude, many times brighter than Venus or Jupiter at their brightest. Also, being able to predict these special events is quite a lot of fun. I love to show off iridium flares to friends when the conditions permit. The Iridium Flares iPhone App costs a mere $0.99 but will pay back many times over.

Enjoy these two apps to see things in the sky that will certainly impress you.

15 November 2010

Leonid Meteor Shower 2010

A very fine meteor shower arrives this week. The Leonids peak on the night of November 17 and morning of November 18th, bringing a fairly reliable collection of meteors to the eastern skies. Best viewing is well after midnight into the early morning hours (around 4:00 AM until sunrise), when the Moon will have set and the Earth is better positioned to intersect more meteors.

Star Date Online has a nice article and image about the Leonids, so named because they appear to originate in the zodiac constellation of Leo. The constellation rises in the early morning sky and dominates the eastern sky. As the Sun does not break the darkness of the morning sky until 5:30 AM, the best darkness will be from 4:00 until 5:30 at which an observer in dark skies can see dozens of meteors per hour. Another good online resources is Astronomy.com with a good article on the Leonid shower.

Image from Astronomy.com.