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The following information will help you get the most from your lighted-polluted environment.

Light-pollution map showing my balcony imaging location in Toronto, population 6 million.

Toronto Light-Pollution Map.jpg

My Light-Polluted Sky

My astro-imaging environment is less than ideal.  Compared to a dark-sky site here's what I'm imaging in...


The Negatives

  • Naked eye limiting magnitude averages just 3.5.

Mag/arcsec2 = 17.2.

Bortle Class 9 sky (the worst class).

  • My enclosed balcony faces northwest at an azimuth of 315 degrees. The ideal would be 180 degrees or due south, so as to view the maximum area of sky possible from a stationary point.

  • I can not see the meridian. This means that I can't image when targets are highest in the sky. By the time a target moves into my balcony's viewing area, it has lost ~8 degrees in elevation.

  • As the balcony is facing a fixed direction I can never see any of the skies behind me.

  • Because of light-pollution gradients I generally don't image below 40 degrees elevation. This limits me to targets with declinations higher than the equator. Because I have another balcony above me I can not image above 70 degrees in elevation. I am restricted again in my imaging area by azimuth due to my balcony's walls. So in azimuth, I'm limited to between 220 and 360 degrees.

  • All told my imaging area is limited to just 16% of the above horizon sky at any one time.


The Positives

  • On a big city balcony nine floors up I have no biting insects of any kind.

  • Being this high up also means no dew on my optics, ever.

  • Travel time from my home to observing site is measured in seconds.

  • Setup time is only ~10 minutes.

  • Having 120vac power means I'll never run out. No batteries needed.

  • When set up I can even observe from the warmth and comfort of my own living room.

  • Maintaining dark adaptation is unnecessary.  The city's light-pollution softly fills the balcony so I can easily see my way around. No more stumbling around in complete darkness.

  • Forgetting to bring something to a remote dark-sky site can be serious.  On the balcony, if I need something I just step inside to get it.

  • A balcony also has full site security. No strangers, curiosity seekers, animals, property owners or police with flashlights will ever show up.

  • Equipment theft is not possible so my suitably weather-protected equipment can remain on the balcony year-round, even the telescope can stay there if I choose.

  • The balcony's concrete floor is hard, flat and without any building sway, no soft earth to sink into.

  • I also know when each balcony's observing session will be cloud-free, I just step outside to check. No more cloudy surprises after traveling to a distant dark-sky site.

  • Observing from a dark-sky site can be expensive as it involves costs for gas, vacation time and even a hotel or cottage, plus meals. My balcony observing site's cost is zero..., every time.


One can see from the lists above there are actually more positives than negatives when using a balcony as an astro-imaging site.

The White Zone

An Urban Astronomer's Light Pollution Guide to Balcony Imaging

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