September 8 2015 Astronomy Newsletter
Here's the latest article from the Astronomy site at BellaOnline.com.
White dwarfs are the corpses of medium-sized stars that have run out of fuel. They typically have the mass of the Sun, while being around the size of the Earth. It's no wonder that early twentieth century astronomers were dumbfounded by them.
*Another total lunar eclipse coming up*
September 27-28 is the date. In the Americas it will start on the evening of the 27th, but in Europe and beyond, it will be the wee hours of the 28th. It looks to be a good one - weather permitting, of course - with totality lasting over an hour. It's the final eclipse of the tetrad that began last year. A special feature of this month's eclipse is that it will happen when the Moon is at lunar perigee. This is when the Moon is closest to us.
You can find out more about lunar eclipses here: http://www.bellaonline.com/articles/art28454.asp
and here: http://www.bellaonline.com/articles/art301030.asp
*New Horizons sending data home*
New Horizons worked flat out taking pictures as it zoomed by Pluto. Getting them home will be a lot slower. However starting last Saturday, more pictures are coming – it will take more than a year to get everything back. The average downlink rate will be around 1-4 kilobits per second, which is less than 10% of the speed for most computer modems. Remember that New Horizons doesn't generate much power and it takes over four and a half hours for transmissions to reach us, even at light speed.
New unprocessed images from the LOng Range Reconnaissance Imager (LORRI) will be added here on Saturdays: http://pluto.jhuapl.edu/soc/Pluto-Encounter/index.php
NASA stays in touch with spacecraft in deep space through its Deep Space Network with antennae in Goldstone (California), Madrid (Spain) and Canberra (Australia). You can actually see which craft are in touch at Deep Space Network Now: http://eyes.nasa.gov/dsn/dsn.html
Please visit http://astronomy.bellaonline.com/Site.asp for even more great content about Astronomy.
I hope to hear from you sometime soon, either in the forum http://forums.bellaonline.com/ubbthreads.php/forums/323/1/Astronomy or in response to this email message. I welcome your feedback!
Do pass this message along to family and friends who might also be interested. Remember it's free and without obligation.
I wish you clear skies.
Mona Evans, Astronomy Editor
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