30 September 2012

The Morning Star and a Real Star

Venus and Regulus align
As the days grow shorter in Autumn and the Sun rises later and later, the early riser is rewarded with a clear view of the Morning Star in the east. Of course, it's not a star, but the very bright planet Venus. Each passing day, Venus moves gradually in comparison to the backdrop of stars and this week Venus aligns itself with the bright star Regulus in the constellation Leo the Lion. The two should make a fine pair, in particular on the morning of October 3rd when the pair will be a tiny distance apart, less than half the width of the Moon. If you are up before 6:30 am, face east and you'll have a fine view of this alignment.

Image courtesy of Sky & Telescope Magazine.

29 September 2012

Comets and Galaxies

One of my primary resources for astronomy information is Sky & Telescope Magazine, and the companion website skyandtelescope.com. I have been a loyal subscriber and follower of this publication for decades, and find the news and information relevant and timely for the amateur astronomer. Two articles recently caught my attention, and I'd like to share them here.

Comet Hale Bopp
Astronomers have discovered a comet that in 2013 may become a very major event. Comet C/2012 S1 was discovered last week, and when it comes in close to the Sun in late 2013, could rival Hale-Bopp as a major comet in the night sky. Let's stay tuned for updates on this one. Comets are wonderful and rare, and a bright one like Hale-Bopp was unbelievable, visible from big cities and spectacular from dark locations. I have memories of driving on highway 101 in the San Francisco Bay Area in 1997, looking at a comet through the windshield of my car.


Hubble eXtreme Deep Field
The Hubble eXtreme Deep Field Observing Team has published a new image revealing 5,500 galaxies, the most distant as old as 13.2 billion years, meaning that it "emitted its photons only 450 million years after the Big Bang." Images like this are not just beautiful, but profound in their richness of information, revealing how far and wide our universe really is, and just how much more there is to discover.

Images courtesy NASA.

16 September 2012

Viewing the Night Sky in City Settings

I am often asked "can you really see any stars in the big city?" Living in San Francisco, this is a reasonable question, since we have a great deal of light pollution in our region, and the sky is often glowing, seemingly obliterating all but the brightest of celestial objects.

Night Sky in an Urban Setting
My answer is always "of course you can see stars and constellations in the City," but it takes some discipline to make the most of urban star gazing. Here are a few factors to consider. First and easiest, you need to give yourself some time for your eyes to adapt to the darkness outside, since most urban dwellers live in well-lit environments, and need to allow enough time for their eyes to adapt before they can see anything. Spending 10 minutes in darkness should be plenty to get things going.

Second and somewhat more challenging, you can see a lot more in a city setting if you view the sky from a dark spot. I don't mean that you have to drive out of town to see stars, but rather you simply need to find a dark spot, the darkest one you can find where you live or a short walk from where you live. For example, in my backyard in San Francisco, there are spots where I can sit or lie to see stars where the light of nearby streetlights illuminates the space, and other spots where I am in the 'shade' of the streetlights. That will make a big difference, since my eyes will respond better to the faint stars above me if I am in the darkest possible spot in my backyard.

Third, you need the local weather conditions to help you out. Lower humidity is good for stargazing, since moisture in the air picks up and reflects light from urban areas, making the sky 'glow' which diminishes the view through the atmosphere out to the heavens above. Similar to humidity, there are other factors that make the night sky more or less transparent. I recommend to use the Clear Sky Chart as a guide to direct you when the skies are going to be optimal for stargazing, whether you do so from the City or the suburbs or the country. There is also an iPhone app for the Clear Sky Chart.

Finally, some kind of optics helps, even in bright city settings. A simple pair of binoculars or a telescope will reveal much more of the sky, even when there is light pollution. Very faint objects will be invisible, but many objects that are not visible to the naked eye will still be present with magnification and good quality optics.

Most important are cloud-free skies, and the patience and commitment to enjoy the night sky.

06 September 2012

Morning Glory

Morning Glory
As the seasonal change of the approaching Autumnal Equinox starts to manifest, the morning sky is still visible when I get up, and the view to the east and overhead is spectacular. The stars of the big, bold winter constellations punctuate the view, with the Pleiades, Orion and Taurus dominating the scene, along with the bright planet Jupiter (and shimmering Venus lower on eastern the horizon). This week, the waning Moon lends to an already-exciting sky, so if you are an early riser, savor a few moments before you start your day, and enjoy the panorama that rises just ahead of the Sun.

Image courtesy of Sky & Telescope.