Urban Astronomy

Light pollution in the Houston area is really very bad. But there is no reason for the urban astronomer to be discouraged. Besides the brightest planets and the moon, there are a LOT of things to see from your backyard or city park.


Moonrise as seen looking along the tube of my Dobsonian reflector. The reflected target of the Telrad can be seen.

I have been able to find things at magnitudes as dim as 8.4 using my 8 inch Dobsonian scope. My dimmest target so far has been the Crab Nebula (Messier object #1) and the conditions were pretty good. I also needed patience and had to used averted vision but it paid off.

The Messier list has proven to be well worth the effort from my light-polluted location in Stafford Texas. One of the things that helps is being prepared, another thing is perseverance, and yet another is a telescope with at least an 8 inch diameter aperture. So I open up Stellarium (desktop planetarium software) or a printed star atlas to see what is up and where it is and I make a plan. I also allow a lot of time for star-hopping and trial and error. Then I have to identify those clusters, galaxies, and nebulae which usually requires several minutes of dedicated observation of the star field often requiring a bit of averted vision.

Urbanization map of the United States derived from city lights data. Courtesy Earth Observatory - NASA

Urbanization map of the United States derived from city lights data. Earth Observatory - NASA

There are lots of resources for those of us stuck with skyglow caused by light pollution. One thing to help block the glare from a neighbor’s lights or streetlights is a screen. I made a simple screen out of two 8 foot wooden fence pickets and some landscape fabric that works like a charm. The height is perfect for blocking out the back porch light from my neighbor’s house.

There is an entire section of the Astronomy.com website dedicate to urban skies with resources and lots of links and then there is Sky & Telescope’s 111 Deep Sky Wonders for Light-Polluted Skies or you can check out the two-part interview with Rod Mollise, author of The Urban Astronomer’s Guide, over at the One Minute Astronomer blog with very practical advice on choosing a telescope to combat light pollution.

Although sometimes it is well worth the trip to get some dark skies, there is so much you can see just from your own backyard. That doesn’t mean you can’t help change things in your own area. Combating light pollution is one of the major goals of the International Year of Astronomy 2009 Dark Skies Awareness Project. Coming up in March, you can even play a part in some simple data collection to help raise awareness about the issue of inefficient and wasteful lighting.

Even with the terrible conditions of our urban and suburban skies, an amateur astronomer has a lot of possibilities with some planning and the right equipment and attitude.

2 Responses to “Urban Astronomy”

  1. Is there somewhere farther out of town where you can easily see the stars? I’m talking maybe 30-40 miles out, some place not too far.

    • There are a variety of spots but the trick is find one that works for you. I can’t for example take my class out to stargaze in the same kind of places I could go with a smaller group of family or friends. But the best place to go is the George Observatory out at Brazos Bend State Park. The observatory is run by volunteers from the Ft Bend Astronomy club and staff from the Houston Museum of Natural Science. Head south on highway 59 (southwest freeway) and take the Grand Parkway exit south of Sugar Land. There are signs to direct you to Brazos Bend. The George has lots of room and is open to the public on Saturdays.

      I like to just drive around and look for spots that would work for stargazing. Be careful not to trespass. ^_^

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