Portal, AZ - Rodeo, NM

Astro Photo of the Month

November 2012

NGC 869 & 884 – The Double Star Cluster

by

Rick Beno

The Double Cluster is the common name for the naked-eye open clusters NGC 869 and NGC 884. NGC 869 and NGC 884 are at distances of 6800 and 7600 light-years away, respectively, making them close to one another in space. The clusters' ages, based on their individual stars, are relatively young. NGC 869 is 5.6 million years old and NGC 884 is 3.2 million years old, according to the 2000 Sky Catalogue.

Hipparchus, a Greek astronomer, cataloged the object (a patch of light in Perseus) as early as 130 B.C. However, the true nature of the Double Cluster wasn’t discovered until the invention of the telescope many centuries later. In the early 19th century William Herschel was the first to recognize the object as two separate clusters. The Double Cluster is not included in the famous Messier catalog, probably because Messier determined that no one would confuse this object as a comet.

The Double Cluster is approaching Earth at a speed of about 50,000 mph. This will bring it into our vacinity in 100,000,000 years, give or take a few.

Finding the Double Cluster is quite easy. These clusters are bright enough to be visible even to the unaided eye, though their appearance is similar to a faint smudge of light in the sky. In binoculars or a telescope this object is considered amazing to most viewers.

At around 7:00 pm this time of the year, look to the northwest about 45 degrees above the horizon. There you’ll see the constellation Cassiopeia, the queen. Cassiopeia’s most noticeable feature is that of a “W”, standing on end, and opened to the left. Now find Gamma Cassiopeia, the center point of the “W”. Below Gamma Cassiopeia, about one half a binocular field away, is Delta Cassiopeia (Ruchbah). Continue scanning in this direction twice the distance of Gamma to Delta and look for the Double Star Cluster.

For additional astrophotos, visit Rick Beno's Web Site at:

http://www.conferringwiththesky.org

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Portal To The Universe

by Fred Espenak

Australia’s Total Solar Eclipse

by Fred Espenak

This year’s total eclipse of the Sun took place on Nov. 14 and was visible from Queensland, Australia (see the NASA Eclipse Web Site for details).

Gary Spears and I led a tour of 40 people to Australia (Spears Travel – Australia 2012) for the big event. We spent three nights in Sydney visiting the amazing Opera House and day tripping to Featherdale Zoo and the Blue Mountains. My wife Pat checked off a bucket-list item by climbing the Sydney Harbor Bridge with Gary’s son Austin.

After Sydney, we flew to a Cairns and bused to Kuranda for two nights camping in Amaroo. The camp was set up by Amaroo owners Don and Judy Freeman and featured comfortable porta-johns (with showers!) and some lavish meals in the mess tent.

The day before the eclipse was mostly cloudy with frequent showers. This made it difficult for me to assemble my two equatorial telescope mounts and nine cameras so I worked mostly in the tent. At the nearby observing site, I polar aligned the two mounts using an angle finder and compass while taking into account the magnetic deviation of true north. The mounts then had to be covered in plastic to protect them from the rain.

On eclipse morning, we awoke to heavy clouds and more intermittent showers. Nevertheless, I hauled the rest of my equipment to the observing site. Everything had to be kept under plastic as occasional showers continued during the partial phases that began shortly after sunrise.

We caught our first view of the Sun just two minutes before totality began as a thin crescent appeared in a hole. I realized there was no time to acquire the Sun with my telescope so I powered up the video camera instead. The Sun disappeared from view once more, only a minute before totality. I could see the cloud covered sky growing dark as the Moon’s shadow approached from the west. Suddenly, the light faded and totality began.

The anxious eyes of 1000+ people in Amaroo searched the clouds for some glimpse of the total eclipse. Fortunately, a hole opened up and we managed to see about 45 seconds of corona and chromosphere. My friend Andy Steinbrecher gave a running commentary of the rewarding views through a pair of image stabilized binoculars. I continued shooting video but was unable to execute my coronal imaging program which requires clear sky during totality. (For example, see 2006 Eclipse – Corona Composites)

About 30 seconds before totality ended, the eclipsed Sun disappeared back into the clouds. I knew when 3rd contact occurred because the sky quickly brightened as totality ended.