When I started astrophotography, I never really understood the huge impact light pollution (LP) had on astro pics. That quickly changed when it became the bane of my existence, the thing that stood between me an superb photos. A lot of beginners rarely consider this, and therefore many novice scopes become great collectors of dust.
Knowing what to expect from your sky can help you better prepare your imaging session, and can help you set realistic goals as to how you’ll get the photos you want.
ISO 1600 | 50mm | f/2,8 | 15sec These images of Orion were taken 2 nights apart. Same camera, same lens and matching settings. Only variable was the location. On the left (and completely blown out) Johannesburg – and to the right (dark, black space…) Sutherland in the Northern Cape. (South Africa)
Know how much LP there is in your area
You can check out your location, or anywhere you’re intending to photographing [here]:
Or if you’re in North America: [Dark sky Finder]
Working around LP
I get a lot of comments on my astro photos about the level of ISO I shoot at [ISO basics]. I don’t shoot higher than ISO400 with my Canon60Da (or any DSLR) where I live. The reason; I catch too much sky glow, and the images get washed out. I generally stick between 60 and 120 sec exposures, and take many images (subs) to average out noise and acquire more data. The key to pushing it is looking at what your Histogram is telling you [Histogram Basics]. An over exposed photo will leave you with little usable data.
Using Filters
There’s a variety of filters available to help cut down LP. They work by limiting certain wavelengths of light – artificial light, or increasing contrast for other wavelengths. [Filters for Astrophotography][The real story on LP filters]
Light pollution to the east by @TheAstroShake
It comes down to knowing your sky and your gear. If you’re really serious about getting great photos, do a series of test photos to edit in an image editing program like Photoshop/Lightroom or the equivalent. Ideally it will always be best if you can get away to a dark location for photography, but that’s not always realistic.
Either way, be patient and be persistent. Don’t stop trying because your photos aren’t turning out like the great ones you see online. Even the greatest astrophotographer was a beginner once….
