Some more data on the Comet 21P/Giacobini-Zinner. 9/10 is when the comet makes it’s closest approach to Earth.
On 9/15, that night, 21P will cross directly through the middle of the star cluster M35 in the constellation Gemini.

Comet 21P/Giacobini-Zinner (“21P” for short) will make its closest approach to Earth in 72 years–only 58 million km from our planet. This small but active comet is easy to see in small telescopes and binoculars as it shines like a 7th magnitude star.

Michael Jäger of Weißenkirchen, Austria, sends this photo of 21P passing through the stars of Auriga on Sept. 7th:

All data here from Space



The eastern sky after midnight through dawn presents a chance to see the Comet 21P/Giacobini-Zinner. It’s in the Constellation Auriga which rises at midnight. From 1230 hours to 0100 hours the comet will be close to the horizon and as the night progresses become higher in the sky.

It isn’t very bright but a pair of binoculars will make it visible. There is a crescent moon; it rises around 0645 so the sky is dark for best viewing. To help find Auriga look for a bright star, Capella, which is in Auriga.

Facing East, look to your left about 30°; 21P/Giacobini-Zinner is located there.


9/3 is a special day for the Earth will pass through a time/space position. For those awake, the auroras should be spectacular.
All are from:


On Sept. 3rd, Earth will cross a fold in the heliospheric current sheet–a vast wavy structure in interplanetary space separating regions of opposite magnetic polarity. This is called a “solar sector boundary crossing,” and it could trigger geomagnetic activity around Earth’s poles. Arctic sky watchers should be alert for auroras when the crossing occurs. Free: Aurora Alerts.

Also is the Equinox solar display, occurring in September and October.


The northern autumnal equinox is now only 3 weeks away. Residents of Arctic Canada don’t need a calendar to tell them that, however. The signs are in the sky. “Last night (Sept. 1st), auroras came out at dusk and kept dancing all night long,” reports Yuichi Takasaka, who sends this picture from Yellowknife in the Northwest Territories:

Displays like these are a sign that autumn is coming.

Researchers have long known that, during weeks around equinoxes, cracks form in Earth’s magnetosphere. Solar wind can pour through the gaps to fuel bright displays of Arctic lights. This is called the the “Russell-McPherron effect,” named after the researchers who first explained it. A recent study covering 75 years of historical geomagnetic records shows that September-October are among the most geomagnetically active months of the year–a direct result of “equinox cracks.”


I had an unusual question from my nephew who just received his first telescope. He was wondering about the terminology used in describing sunup and sundown. It is as follows:

  • Actual time: the time when the officially sets in your area.
  • Civil Twilight: The time when the sun is no more than six degrees 6° below the horizon You can carry on outdoor activities. Depending upon your location, this is approximately ½ hour after Actual time.
  • Nautical Twilight: The time when the sun is more than six degrees 6° below the horizon but less than 12° below the horizon. There is light in the sky. Objects can be seen but are indistinct. The horizon is outlined. Ordinary activities cannot be done without artificial illumination. Approximately one hour after actual sunset.
  • Astronomical Twilight: The time when the sun is more than 12° but less than 18° below the horizon. The sun does not contribute to sky illumination. Approximately 1½ hours after actual sunrise or sunset.

These times don’t vary; your physical location but the time of day depends upon your latitude and longitude.

More on this can be found at or at Wikipedia. Most of these times are for navigation and legal definitions.
Using Weather Underground will require you to put in your nearest city or town. You can then select weather stations nearest to you.



At 2000 hours on 9/3 one can see the Cluster M-2 in the ESE sky. The will have set about 5 minutes prior, but you will be looking at a darkening sky. Aquarius will be on the horizon and rising. Pegasus will be up to the east.All this sits about 110°, that’s 10° to the south of east. this globular cluster can be seen with a pair of decent binoculars; a small telescope is better. After viewing something as star filled as this, is it possible that life exits on one or two planets around a couple of those stars?


Here’s a preview of September Skies. At different times during the month, features of Sky and Space will be posted.


By all reports, this year’s Perseid meteor show is the best ever. Might be worth giving up some sleep.

‘Brightest ever’ Perseids meteor shower revealed in stunning new photos, ahead of the final chance for stargazers to see the shooting stars TONIGHT

The Perseid meteor shower arrived this weekend, stunning stargazers around the world as more than 70 shooting stars flashed across the night sky every hour.
Known as the ‘fiery tears of Saint Lawrence’, the celestial showcase takes place each year when the Earth ploughs through the galactic debris left discarded by the passing of the Swift-Tuttle Comet.

People both north and south of the equator were able to watch and photograph the stunning celestial showcase this weekend, and will enjoy one final opportunity to see the Perseids tonight.

Those in mid-northern latitudes will have the best views of the display, with stellar views expected across the United States, Europe, and Canada. [snip]