Astrophotography: How to create interesting photos of the night sky (even in light polluted skies)
Updated: Nov 8, 2022
In this post I'll go over the basics that I have learned about finding and sharing compelling content in the night skies. I shoot in heavy light pollution (somewhere around a Bortle class 8-9 but we'll get into that later) and you can too, even in the worst of skies there are always a few opportunities to come up with something interesting and unique.
I'll cover a lot in this post, at times I'll explain some very basic photography topics. If you're an experienced photographer with little or no astrophotography knowledge, this post will have you shooting celestial objects in no time. There will be sample photos and videos throughout, so if I'm covering something you're not interested in you can scroll down until you see an image that you like and can resume reading from there.
Let's look at some of my images so you can see what you can capture.
All images in this post belong to me and little or no editing is done to them, nothing is "faked," these are results that you can achieve easily with a little practice. I keep my images pretty authentic, the biggest alteration you will see is stacking multiple images to effectively create an especially long exposure shot.
From photographing the International Space Station with a phone to capturing planets with an inexpensive telescope to using a standard DSLR to shoot in intervals and create a stacked image with a surprise guest, this is all easy to do and can be aided with free software.
Shoot for the moon
The object in the night sky that most frequently provides us with moments we want to capture is the moon. This can be done with a phone, or a standard DSLR with a common 300mm zoom lens. Both cameras will require basic knowledge of shutter speed, aperture and ISO, and how to adjust them on your camera. It is common now for phones to allow you to make those changes, or there are apps you can download if your phone doesn't have that feature natively.
A photo taken of the moon with a phone using all automatic settings will be a very small, featureless, overexposed blob, let's address exposure and then see what can be done. A DSLR with zoom will handle this a bit better, but will still need roughly the same camera settings.
The moon generally reflects a lot of sunlight, so short exposures allow you to capture detail in the craters without blowing out the image. Start by using 1/100th of a second shutter speed (how long the shutter is open), f/11 aperture (how wide the shutter opens), and ISO 100 (how sensitive the sensor is to light). It is best to keep your ISO low, but editing software and stacking images are ways to work around the noise that higher ISOs can generate. I don't like to go above around 400 or 800 though quality cameras can handle much higher ISOs easily.
The 1/100th shutter speed, f/11 aperture and 100 ISO is referred to as The Looney 11 Rule (it's a counterpart to The Sunny 16 Rule) and it's a good way to remember what settings to start with. It shouldn't be referred to as a rule, it's a starting point for your settings. Try a few shots, see how they look and adjust from there. The phase of the moon, the camera, the light conditions etc. all are factors in your settings. Usually a low exposure of the moon is preferred so you can see its features, a full moon may be shot better at 1/200th shutter, a crescent at 1/50th, just see what you like.
A DSLR with 300mm zoom will be able to make the moon fill up a reasonable amount of the frame with the optical zoom of its lens. A phone may have a small amount of optical zoom but will rely heavily on digital zoom, which is the same as just cropping in on your image. Your phone shoots high resolution images, don't be afraid to try a little digital zoom if you have to, you'll begin to notice when the image starts falling apart.
If you don't own a DSLR and you've decided you really want to get into photographing the moon without spending the money on a camera and a zoom lens, there is a much less expensive yet highly effective way to achieve the results you want. A telescope or a pair of binoculars will provide you with the zoom you need. You can buy a simple mount for attaching your phone to the eyepiece or for quick shots of the moon you can get away with holding your phone's lens up to the eyepiece of the scope and snapping a photo.
Here's an example of a $150 telescope that is easy to use and can provide amazing images by simply placing your phone on the eyepiece:
I read through many reviews on that site and they seem to have well informed, unbiased opinions. Look around there at other scopes and see what fits your budget. My recommendation is start with the fewest fancy features first. You'll go to the top of your budget for a scope that's at the bottom end for what it offers, pick something that's easily affordable for you and has good reviews for its price range. Later you'll be able to make a better decision on more expensive gear if you decide that's what you need.
Spot the Station
Now you've got an idea of adjusting settings for your camera, you've taken some shots of the moon and you're wondering what else to try. The International Space Station is hurtling around the planet 254 miles above us making a complete orbit of the planet about every hour and a half. It's orbital inclination means that its orbital path is always changing. You might have a few consecutive days or more of sightings where you are, you might go a month without one. Around dawn and dusk, it's easily observable with the naked eye if it's passing over you. In the daytime the skies are too bright to notice it, at night it's behind the Earth's shadow. NASA, Stellarium, and Heaven's Above all have great sites and apps for ISS sightings, as well as other invaluable resources for astrophotography.
Here are a few examples for you:
Find a sighting that works for you taking into consideration your surroundings. Passes with an elevation of around 30° or less could be difficult for you to spot due to trees or nearby houses, but they do allow for creative compositions. Passes directly overhead (near or at 90° of elevation) are the brightest and the easiest to spot, but might not provide interesting images. The ISS will look like a quick moving jet across the sky with no noise associated with it, just making a long, smooth, gentle arc across the sky. It's an interesting sight.
This was taken with my phone and a steady hand, camera switched to Night Mode but no manual settings adjustments. If you have a tripod or any kind of kickstand for your phone you can experiment with long exposures where the ISS will create a streak across the sky. A shutter speed of 5-10 seconds helps make the ISS show up and is short enough to keep the stars from starting to blur too much
Star trails and timelapses
Once you have a camera and tripod or a way to keep your phone steady for a long time, then all you need is an interval setting for your camera (or get an intervalometer for your camera, or an app for your phone) and take 5-10 second long exposures over and over for an hour or more and you can use those images to create a timelapse (your camera or phone might have this feature, there are free software options available) to effectively speed up time and give you a better view of what's going on in the night sky.
Alternatively you can use free software such as Registax to stack the image, giving it the appearance of a single extremely long exposure photo. The stars will create trails through the sky, geosynchronous satellites will become obvious as individual dots (tumbling space trash can result in this as well), and
occasionally you get a surprise in your shot like you see in the one above.
Observing the planets in our solar system and their moons
With a DSLR and 300mm zoom lens, I decided to take a look at Jupiter. Autofocus isn't going to work right for stars, so I was dialing in the manual focus and zoomed all the way in with the lens, then digitally zoomed all the way in on my live view and I had no idea that gear would allow me to see Jupiter's moons. The image quality is poor due to the digital zooming/cropping, but I was seeing the moons of another planet for myself, not through the images of someone else. I wanted more zoom, and the next step up in zoom lens is very expensive. As mentioned before, telescopes are far less expensive than zoom lenses, so I thought I'd give it a shot.
With the purchase of a simple, inexpensive telescope I was looking at Jupiter and its moons, Saturn and its rings, as well as tons of objects that are just too faint to be seen with the naked eye in the light pollution surrounding my area. Using a cheap mount for attaching my phone to the telescope allows me to get images like this. With your eye to the eyepiece objects like Saturn will be very bright with little detail to discern. Attach your phone, then decrease the shutter speed until you start to see details like this come out in your image. Don't be afraid to use digital zoom in these situations.
In less than an hour I was capturing photos and video that I thought required expensive gear and extensive knowledge. Experiment with different exposures and different magnifications. Soon you'll be exploring deep space objects and stacking images, but that's a topic for another post.
As you get further into astrophotography, light pollution maps are extremely useful and I usually use this one that provides a color-coded representation of light pollution and you can also click on any location to pop up a box that tell the Bortle class for that spot. The lower the number the better, but even Class 5 skies offer skies you've forgotten about if you live in an urban area.
If much of this was new information for you, then there's a lot to cover regarding shooting in RAW as opposed to JPEG, stacking images and much more, those topics are best covered in their own individual posts.
I hope I was brief but thorough, informative but not boring. Go out and see what you can create. Share your images on Instagram, tag panther_city_air and also feel free to ask any questions you might have. Clear skies!