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.