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.

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.

Comets:

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.

Galaxies:

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.

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.

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.

The Galactic Center: Staring Into the Heart of the Milky Way

Summer is prime time to look into the heavens and touch the wonder of the Galactic Center, the heart of our own Milky Way galaxy. Two bright constellations guide you to the center of the Milky Way, Scorpius and Sagittarius, which are easy to spot due south each evening shortly after sunset.

The Galactic Center

Our own Sun and Solar System occupy their special place 30,000 light years from the center of the Milky Way, and as we look out and around us into space, we view our own galaxy from within, along the spiral arms and toward the center. Many have seen the lovely band of the Milky Way when camping or far away from city lights, but the faint river of light is all but invisible in any urban area. Nonetheless, with binoculars, you can see deeper into the sky and discover some of the deep space wonders and faint objects that are visible between our own location and the center of the galaxy, an area full of star clusters and nebulae. So I encourage everyone to get a pair of binoculars, face south, and using the star chart (above) as a guide, aim between Scorpius and Sagittarius and meander from there upwards. You will encounter the Lagoon Nebula and the nearby Trifid Nebula, easily visible in city lights if you use a telescope or binoculars, and many more Messier Objects, the fuzzy blobs that dot the sky near the Galactic Center.

In six months, when the Earth has traveled half-way around the Sun, we'll be able to look in the opposite direction, toward the Galactic Anticenter, as I have described in a previous blog post. That is interesting to consider, but more exciting is the Summer when we can enjoy our own galaxy's finest wonders on full display.

Here's a link to an image of the Galactic Center on Sky & Telescope's website.

Image courtesy SkySafari.

Planet/Star Trio Fades into the Sunset

The "Trio" fading into the sunset

I've enjoyed watching the changing view of the evening sky over the past months, in particular as the pair of Saturn and Spica have become a trio with Mars. Saturn and Spica straddle the ecliptic and Mars has raced from its location far to the west of the pair in Spring, to a near-split of the two last week, and now as the trio fades into the sunset, Mars is continuing to glide eastward, this week being joined by a crescent Moon.

I've been pointing out this dynamic at star parties for the past few months, as it vividly illustrates the motion of planets in our Solar System, and it also highlights the differences in perceived speed of the outer planets, with Mars circling the Sun every 2 earth-years, and Saturn taking nearly 30 earth-years to accomplish the same.

Image courtesy Sky & Telescope.

Perseid Meteor Shower 2012

The big meteor shower of the year, the Perseids, peaks this weekend and promises a good show for all who can find dark skies and have the patience to enjoy them. The Moon will generally cooperate with viewers since it will only interfere very late into the night, and even then will only cast a small amount of glare on an otherwise exciting event.

The Perseids are a regular meteor shower that peak over one or two days each August as the Earth plunges into a stream of particles from the comet Swift-Tuttle. As we impact these particles at tens of thousands of miles per hour, we enjoy a spectacle of shooting stars darting across our night sky, sometimes one per minute, sometimes less or even sometimes more. Your ability to see more meteors depends upon three things: (a) dark sky, (b) dark adaptation, and (c) lateness of the night. The darker the sky, the fainter the meteors you will see. The longer you are in your dark environment, the better your eyes will adapt to the dark and enable you to see fainter objects. And finally, later in the night the Earth is intercepting more and more meteors, right up until the first light of dawn.

The shower peaks on Saturday night August 11th and Sunday night August 12th. Your best bet in the San Francisco Bay Area will be locations away from city lights with good views across the entire sky, but in particular with a good eastern horizon.

EarthSky has a helpful article about the Perseids. From EarthSky: "They radiate from a point in the constellation Perseus the Hero. You don’t need to know Perseus to watch the shower because the meteors appear in all parts of the sky. The Perseids are considered by many people to be the year’s best shower, and often peak at 50 or more meteors per hour in a dark sky."

Watching the Solar System in Action

As we move into August, we can witness the gradual change in the night sky from one evening to the next as planets near and far align and move among the backdrop of stars in the heavens. In particular, Mars is moving quickly in its path around the Sun, and as it does so in early August, it will move just between a pair of bright objects, the star Spica and the planet Saturn. The diagram illustrates the position at the end of July, and the spacing between Mars and the pair will close as we move into August. This is a superb opportunity to witness the motions in our Solar System as we on Earth move around the Sun (making the trio of planets and stars appear lower in the sky each night), and Mars moves eastward with respect to Saturn.

Image courtesy of Sky & Telescope.