Astrophotography Learnings

Updated: Apr 2

Astrophotography has always been a huge interest for me with regards to sub-types of landscape photography. Although it tends to be a little more difficult and time consuming to pull off as effectively as some of the other photography that you can see scrolling through my portfolio. If you follow my Instagram account, you might have seen a couple of my early attempts at astrophotography already. These pictures for the most part are nothing special, outside of the sky being amazingly beautiful on a clear night.


These pictures worked okay for a few Instagram posts on social media, but for most other applications the images are not adequate to be used. Most of the learnings for me with this type of landscape photography have come down to three things: gear, location, and weather. Processing can also be more difficult for the stacking of images, but I will save discussion of this subject for another blog post. While I do have a newer photo in my saga to master this form of photography, I still do not have anything outstanding to show. You will just have to wait for the next installment of an astrophotography post later this Summer for that!


25 seconds at F/1.8, ISO 5000, 24mm (NIKKOR Z 24mm F/1.8 S): 6 Image Stack

Now, let us dive into the issues I have had and some remedies that might help others attempting to get into this type of photography. Starting off with the issues that are induced by the type of gear that I have been using up to this point.


GEAR

NIKKOR Z 24mm F/1.8 S and NIKKOR Z 24-70mm F/4 S Mirrorless Lenses

The lens pictured on the right above was the first lens I had for my camera. The kit lens that comes with the Nikon Z6 and Z7 mirrorless cameras. This lens is honestly quite impressive, and if you are curious to learn a bit more about it you can check out my blog post comparing it to the Nikkor 24-70mm F/2.8, which is the sharper, professional version of the lens. However, without additional equipment it cannot do a particularly good job in low light conditions due to the F/4.0 aperture size. You can capture stars with this lens using a few different tricks, but it is more difficult to get the stunning shots and reduce image noise.


This difficulty arises due to the stars in the night sky being constantly in motion. When things get dark, one way to get more light onto the sensor is to increase the exposure time but if your exposure time is too long then you begin to get star trails. Instead of your stars looking like stationary bright dots, they look like little lines. The common rule of thumb for the field is the 500 rule. You divide the focal length that you are shooting at by the number 500. This gives you the approximate max exposure time you should use to avoid star trails in your photos. This rule is not 100% accurate but is fairly accurate to use for general purposes.


With this in mind, this limits my 24-70mm lenses to exposure times of about 21 seconds. This can capture a good amount of light but leaves out some of the details of the milky way, if you are shooting this. Barring exposure length and aperture settings, this means that you must boost your ISO up to high levels which introduces a large amount of noise. As my beach milky way shot shown above is at an ISO of 5000.


This means that the characteristics that effect astrophotography the most in a general sense are how low the aperture on your lens can go, and what focal length you are shooting at. Specifically, that wide angle shots of the sky tend to be common in an attempt to increase the exposure time that you can use. Which led me to make my original purchase of the NIKKOR Z 24mm F/1.8 S lens in an effort to get better low light performance from the better aperture range. At the time, Nikon had not released their 14-24mm lens which I might have gone for instead.


30 seconds at F/1.8, ISO 4000, 24mm (NIKKOR Z 24mm F/1.8 S): 8 Image Stack

With the new lens, I was able to get better clarity and slightly less noise out of the pictures. But I kept hitting the issue of the exposure time that I wanted to use to try and offset the need for higher ISO settings. In the example above I used 30 second exposures on the 24mm lens with ISO of 4000. There is clearly less noise in the stars and more detail in the milky way, but the star trailing becomes distracting at this point making for a less than ideal image.


This brings me to the final piece of equipment that I obtained in my quest to figure out astrophotography, the star tracker. The one I purchased was the iOptron Star Tracker Pro. The idea behind a star tracker simply stated is that once it is aligned with a particular star, Polaris, you can then take long exposures of several minutes without star trails being an issue. Honestly, this one piece of equipment makes most lenses viable options for astrophotography. It has been a learning process getting to this point, but it you are also interested in astrophotography I would recommend looking at getting a star tracker over buying a new lens. It is probably cheaper, and it works better once set up properly.


iOptron Star Tracker Pro Tripod Attachment

I have had limited time with my star tracker and have been getting good results so far. Examples of my good photos to come in a future blog post along with how to set up a star tracker so make sure to check back regularly!


This weekend I did my first waterfall with a stary sky background. This required getting to the location before dark, setting up the shot and star tracker, taking a photo of the waterfall during dusk, and then hanging out until after dark. This was mostly a test run for myself in planning a star night sky shot and a waterfall foreground, so I did not spend as much time in photoshop making sure the photos merged correctly.


90 seconds at F/2.8, ISO 1000, 24mm (NIKKOR Z 24-70mm F/2.8 S): Single image for sky

The observant among us will notice that I goofed up the focus settings for the camera while taking the shot for the sky. However, there is no star trailing despite the exposure length being an entire minute and a half! This allowed a reduction in ISO all the way down to 1000 and really cleans up the image quality, eliminating the need to do image stacking to cut down on the high ISO noise. Additionally, this was only with performing a "rough" alignment of the star tracker to Polaris using only a compass and level as opposed to using the sight glass to precisely line it up. While the picture is still not adequate for my portfolio, we are getting much closer to where I want things to be at.


LOCATION

Stock art from Wix

My search for the right equipment to use for astrophotography really accounted for the bulk of my problems. However, as humanity expands to the far reaches of the globe there are fewer and fewer locations that are truly dark enough to get the best milky way photography. While it is important to have the right process and equipment in order to capture the light you need to, being too close to humanity can cause a light glow across the photo. There are some editing tricks to help reduce this so that you can take astrophotography nearby smaller cities, however it is something to consider when planning shots at night.


In my research I have found a couple decent resources for finding darker areas nearby that might be viable for some astrophotography.

These two resources work wonders. Typically, I use the Light Pollution Map while at home perusing locations in a web browser. I will then use the Dark Sky Map when I am out and about, or in the field. This mobile App is available for both Android and iPhone devices so it should be viable for everyone that is interested.


When it comes to astrophotography, I have learned it is super important to have your shooting location figured out ahead of time and to arrive before dark to get setup. Even if you are not planning on capturing the foreground during daylight hours, setting you scene in the dark is rather difficult to do and can result in getting home disappointed with what you capture. It is also important to note that if there is a lot of trees in your foreground, you may find it difficult to properly process the image in photoshop later. You can see a bit of this from the tree and waterfall shot that I posted above. Which leads us to part of the next topic, weather.


WEATHER

1/15 second at F/8, ISO 800, 140mm (NIKKOR Z 70-200mm F/2.8 VR S)

Weather plays a large role in the success or failure of an astrophotography venture. Preferably you want a clear skies night if you are going for milky way shots or longer exposures. However, you can get away with the weather being slightly overcast if all you want is some stars in the sky to accent your foreground.


One thing that you might not think about right away in regards to weather is actually wind. In the section on location, I briefly talked about the difficulties of processing an image with a lot of trees nearby in the foreground. This can be expanded upon if it is fairly windy, and the trees are moving around a lot. Especially if you did not capture the foreground shot during daylight hours. The large amount of movement paired with longer exposures will leave your foreground looking rather soft overall and might not be the result that you want.


If you do arrive at a location after dark and it is rather windy, one way around this could be to simply find a slightly different foreground. Maybe look for rocks, or lower hanging plants that are low enough to be out of the wind. Or even a barren tree might be stationary enough to work.


Stock art from Wix

The final detractor to starry night photography is from the moon. When the moon is up in the sky it creates a large amount of light pollution that blocks out the light coming from stars in the sky. The moon goes through a full cycle from full moon to new moon, with the moon being present in the night sky for varying amounts of time throughout the night. You do not have to wait for a new moon to take good astrophotography photos, but it is helpful to get a tool to track the moon stages, moon rise time, and moon set time so that you can plan ahead for your shots.


I track the state of the moon with a wonderful photographer's tool called PhotoPills. I'll have to do a blog post at some time about the benefits of using this tool but for now I'll just bring up that it has a widget tool that can be used to give you the percentage of the visible moon in its current cycle, what time the moon will rise, what time the moon will set, and the duration of the night that can be accounted for without there being any moon at all. The included widget also has some other useful information such as the exact time frame for the sunset/sunrise, golden hour, blue hour, astronomical hour, and time period from which the galactic center is visible from where you are located.


As I learn more information, I will make additional blogs posts to share my knowledge of this type of landscape photography. I hope the information presented here that I have already learned in my endeavors proves as a useful starting ground for anyone that is just getting started in astrophotography to help avoid some of the early failures of trial and error with regards to what works and what does not. With this said, please be on the lookout for future information on processing star shots, image stacking, polar aligning star trackers, planning photos, and more. Until next time, have a good one getting those shots!


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