A total solar eclipse has two main phases: a partial and a total one. Here’s how to shoot both!
We are less than a lunation away of probably the most advertised total solar eclipse in history. On August 21 2017, we will witness what was dubbed “The Great American Eclipse”. The shadow of the Moon will sweep across the United States of America, from Oregon to South Carolina. And, of course, we want to take photos of it. Let’s see what we can do…
The solar eclipse
First of all, let’s talk a bit about the eclipse. If anyone still has doubts, a total solar eclipse occurs when the Moon gets between the Sun and Earth and manages to fully cover the disk of our beloved star. This doesn’t happen at every New Moon, as the orbit of the Moon is inclined at an angle of around 5 degrees to the Ecliptic. The points where the orbit of the Moon and the Ecliptic intersect are called lunar nodes. So, we need the New Moon to happen close to one of the nodes in order to have a solar eclipse. (If we have a Full Moon close to the nodes, we get a lunar eclipse.)
But this is not the only condition needed. We also need the Moon to be close to perigee so that it covers the whole disk of the Sun and allows the magnificent corona to be visible. Otherwise, we have an annular solar eclipse, when a thin ring of the Sun is still visible around the dark disk of the Moon.
Phases of the eclipse
A total solar eclipse has two phases: a partial and a total one. The first partial phase happens between contacts 1 and 2 (C1 and C2), totality happens between contacts 2 and 3 (C2 and C3) and then we have another partial phase between contacts 3 and 4 (C3 and C4), when the eclipse ends.
Totality is only seen from a thin path across the globe, where the umbra touches the surface of our planet. It will be around 115 km wide in the case of this eclipse. The penumbra will cause a partial eclipse visible from a much larger area; even the extreme West of Europe will get to see a low magnitude partial eclipse. The 2017 eclipse will be seen as total from 14 American states, although it will barely touch Montana and Iowa.
The umbra will reach the North American continent, in Oregon, at 17:16 UT (10:16 AM PDT) and, just 94 minutes later, it will leave continental USA, in South Carolina. That’s fast, right? Around 2335 hm/h (1450 mph).
So, what’s the best place to see it?
First of all, you need to be inside the path of totality. It’s a huge difference between a 98% partial eclipse and a total one. Go for totality, if you can. Then, the only factor that needs to be taken into account is weather. The sky has to be clear in order to see the eclipse. According to secular weather reports, it seems that the best chances for good weather on eclipse day are in the Western half of the US. But, weather is weather. Not climate. Check out Jay Anderson’s excellent Eclipsophile website for climatological data and updated forecasts. Another problem might be smoke from forest fires, so keep an eye on those, too.
It would be great to have at least one back-up location in case your main one gets a bad forecast. Watch weather reports starting at least one week in advance and see the trend of the weather in different areas. Keep in mind that it will most likely be impossible to relocate on eclipse day due to high traffic. If possible, visit your main and back-up locations a few days before the eclipse. My main location will be in Western Wyoming, close to the border with Idaho with two alternates: one in Idaho and another one in Wyoming. I will probably make a final decision one or two days before the eclipse, but I will be prepared to change location, if needed, 6 hours before the eclipse.
How to view a solar eclipse
Before getting to the photography part, I have to stress the importance of viewing the eclipse in a safe way. Do not look at the partially eclipsed Sun without proper filtration. The filter will always be placed in front of the instrument you are observing through. You can choose between Baader Astrosolar Film, polymer or glass filters (like this).
If you don’t have an astronomical instrument and you only want to look at the eclipse with the filtered naked eye, get a pair of “eclipse glasses” (like these) or handheld viewers. Be careful where you get them from and check if they meet the ISO 12312-2 international standard. Do not use any improvised filters. You can permanently damage your eyesight or even go blind.
It is totally safe to watch the total phase of the eclipse without filters. In fact, you will not see totality through filters. But never look at the Sun without proper filtration outside totality! If you don’t have a safe solar filter, watch the partial phase by projecting the Sun through a pinhole on a white screen.
How to photograph a solar eclipse
And now let’s find out how we can take some photos of this eclipse. Or any other one.
First question: what camera do I need?
Answer: Any camera will do.
Even with a mobile phone camera you will be able to record the moment and have some photos that will look pretty decent. I’m planning to use my phone on video mode to record people’s reactions. Point and shoot cameras (even ones that only have an Auto mode) will do a pretty good job at getting a wide angle view of the eclipse.
A DSLR or mirrorless camera will be a better choice for the serious photographer as it allows for multiple parameters to be set and can also be remotely controlled. And this is a very important aspect if you plan to shoot multiple cameras during totality.
Actually, more important than camera selection might be the focal length that you want to shoot the eclipse at. And here you have more choices, depending on what you want to achieve.
What focal length to use
For detailed images of the corona during totality you will need at least 200mm of focal length on a full frame camera. If you choose a photo lens or a telescope is entirely your choice and depends on the gear you own. Below is a comparison of the size of the eclipsed Sun at different focal lengths. The outer frame is for a full frame sensor. The yellow rectangle is the Nikon APS sensor, while the red rectangle is the equivalent of a Canon APS-C sensor. The green rectangle is for Micro Four Thirds sensors.
In my opinion, the ideal focal length for images of the Solar corona is between 400 and 800mm for a full frame sensor. In case you want to capture the prominences around the Lunar limb in greater detail, go for a 2000mm focal length telescope on a full frame camera. A Maksutov or Schmidt-Cassegrain should do it as they are more compact and easier to carry.
If you want to shoot landscapes with the eclipsed Sun in the frame, you will need a wide angle lens, as the Sun will be pretty high up in the sky (around 50 degrees). Think about something in the range of 14 to 24mm on a full frame. A fisheye might also be useful.
What other gear is needed?
You need a solar filter (like these) to photograph the partial phases.
Don’t try it without a filter as you may damage the sensor of the camera if shooting in Live View mode or it may cause problems to your vision if you frame using the viewfinder of the camera. If you go for Baader Astrosolar filter, the partially eclipsed sun will have a blue tint. Through glass and polymer filters, the Sun has a more natural colour. Personally, I like glass and polymer better just because of the colour. Practice putting on and taking off your solar filter. Adjust its size if this doesn’t go smooth.
Use the sturdiest tripod you can get. It might be windy or you might have people walking around your gear and that will cause vibrations.
Remote shutter release cable
Pressing the shutter button on your camera will induce vibrations in the system. That will result in blurry images, especially at longer focal lengths. Use a cable release. I always prefer cable releases over infrared or radio ones as you don’t need batteries to operate them and there are fewer things that might not work. You will need an intervalometer, if you plan to shoot a sequence of the whole eclipse from a fixed tripod.
Have at least one fresh spare battery if you shoot with a DSLR and two or three if you shoot with a mirrorless. If it is your first eclipse, you might get carried away and shoot more photos than planned during the first partial phase of the eclipse and the battery might deplete.
Fast memory cards
Use memory cards with fast writing speeds as you will need to shoot in burst mode for Baily’s beads and the diamond ring. If your camera has a dual card slot, shoot on both cards at the same time to have a back-up.
Camera adapters (optional)
If you’re shooting through a telescope you will need an adapter from your camera to the focuser.
Equatorial mount (optional)
If you plan on shooting totality at a longer focal length, you will need a tracking equatorial mount. On one hand, it will be easier to keep the Sun centred in the field of view and on the other hand you will need tracking if you plan to use longer exposure times for the fainter parts of the corona or for shooting the Earthshine. Learn and practice polar aligning during daytime.
Laptop computer (optional)
If you want to automate the process of shooting the eclipse, you will need a laptop. More on this later.
Duct tape, Allen wrench, Swiss knife, screwdriver, etc. These things should always be part of your astrophotography kit. You never know when you need them. And, usually, you need at least one or two of these items every time you go out and shoot upwards.
One important aspect about gear. Don’t shoot a total eclipse with new gear. Use only devices that you are very familiar with. Shooting total solar eclipses is an act of coordination and it is very easy to make mistakes, no matter how experienced you are. Read manuals, practice, practice and practice even more. Know your gear inside out.
And make a checklist of the whole equipment needed. That way you will be sure that nothing is left behind. If you travel to the US for the eclipse, go through your checklist twice: once before leaving your home country and once one day before the eclipse.
Focusing is critical for eclipse photography. Not that it is not for any other aspect of astrophotography.
Use the Live View feature for easier focusing. If your camera doesn’t have a Live View mode, use a right angle viewfinder. Put the solar filter on your lens/telescope, turn on Live View and set it to Exposure Simulation, bring the Sun in the field of view of the camera and use 10x magnification in Live View. The easiest way is to focus on a sunspot if we will be lucky enough to get any. If no sunspots will be present, focus on the Solar limb.
Once you achieve focus, tape down your focus ring if you use a photo lens. Tape down the zoom ring also, if you use a zoom lens. If you shoot through a telescope, lock the focuser.
Check focus from time to time, as thermal effects may affect it. Once you get closer to totality do a last focus check 2-3 minutes before the third contact. Don’t do this closer to the start of totality as you might end up shooting nothing. Consider bringing a black cloth to put over your head and camera when focusing; it will prevent glare.
Wide angle lenses should be able to auto-focus on the eclipsed Sun.
What to shoot and how to shoot it
It depends on what setup you plan to use.
Wide angle lens on a tripod
This is the easy approach and I totally recommend it if this is going to be your first total solar eclipse.
You will need a tripod, a camera, a wide angle lens and a cable release. The Sun will be pretty high in the sky so you will need to have some important/large/dramatic object in the foreground in order to get a well balanced image from a compositional point of view. You can even think about shooting panoramas.
Here’s the aspect of the whole sky during the eclipse as seen from Casper, Wyoming, USA. It’s a simulation done in Stellarium. It will look pretty much the same anywhere along the path of totality.
As you can easily see, no less than 4 planets will be visible during totality: Mercury, Venus, Mars and Jupiter. Bright stars like Sirius, Betelgeuse, Rigel, Capella or Arcturus will also be visible. Look out for Orion above the South-Western horizon.
Let’s zoom in a bit and have a closer look at the South-South-Eastern horizon; also simulated in Stellarium. I added an alt-azimuthal grid so that you can choose the best lens to fit all the elements you want to shoot. Plan your framing ahead using apps like Photographer’s Ephemeris or PhotoPills.
A nice project for a wide angle lens is a sequence of the whole eclipse. You start at C1 and end at C4. Use a filter for partial phases. Shoot a photo every five minutes, let’s say, and then assemble all the photos in Adobe Photoshop using the Lighten blending mode. Use your totality shot as a background.
Experiment with exposure times and apertures during totality. Start at ISO 400 f/5.6 and 1 second of exposure time. It might be even better to trust your camera for this shots and you will have more time to actually watch the eclipse. Aperture priority and Auto modes will produce really great images.
Telescope or long telephoto lens
If you want to shoot the partial phases, you can use a longer focal length to get more details on the surface of the Sun. Like sunspots. Don’t forget to shoot through a solar filter. Partiality can also be shot through a H-alpha telescope. Test exposure times before the eclipse using the un-eclipsed Sun at the same height in the sky as during the eclipse. It will be the same thing, even if part of the Sun will be covered during the eclipse.
Around 30-40 seconds before totality, you can take the filter off. But don’t look at the Sun yet through an instrument without a filter. You can watch what happens on the display of your camera. Take a deep breath and prepare for some of the most intense moments you will ever live.
A few seconds before totality, you will see the diamond ring effect and Baily’s beads. Both are short lived and extremely beautiful. Here, you will need to shoot in burst mode as the aspect of the beads changes very fast and the ring is ephemeral. You can start shooting for the ring and beads around 10 seconds before second contact.
Right after second contact, the chromosphere is revealed. And, boy!, what a beauty it is. Be fast as it is only visible for around 10 seconds after second contact and 10 seconds before third contact. You will see prominences around the Solar disk. I can’t say anything about their size or shape but don’t expect any huge ones as the Sun is around its minimum of activity. You will need short exposure times for this.
Corona is next on our list of photos. My favourite focal length for this is 500mm as it reveals all those long coronal streamers in a longer exposure.
There is no right or wrong exposure for the corona. The dynamic range of the corona is so huge, that you can use pretty much all exposure times available on your camera from 1/4000 to, let’s say, 6-8 seconds and you will get a different aspect of the corona in each image. With short exposure times you will get the bright corona close the Solar disk and with longer ones you get the faint streamers a few Solar radii in length. Of course, in this case, the inner corona will be overexposed. Long exposures will also reveal Earthshine on the Moon.
If you decide to go for longer exposure times, you will need a tracking mount to get sharp images. If luggage size is not an issue, use your equatorial mount. If you are limited by luggage size, use a star tracker like the Fornax LighTrack II, Astrotrac or Skywatcher Star Adventurer. Be sure to polar align your mount (hint: use a compass and an inclinometer – app or real one; don’t forget about magnetic declination) and to use Solar tracking speed.
Also, think about using Mirror Lock-Up if you can’t shoot in Live View mode. The flip of the mirror will make your whole imaging system vibrate which will result in blurry images.
Check out this solar eclipse exposure table
I compiled a solar eclipse exposure table, using Xavier Jubier’s Shutter Speed Calculator for Solar Eclipses. Keep in mind that these exposure times are just suggestions. Bracket, bracket and bracket even more.
Keep after-shooting processing in mind
In order to have a correctly exposed image of the corona along its full width you will have to merge all your individual shots taken during totality. But this is no easy task. Use a HDR image software in conjunction with a Photoshop technique to enhance structures in the corona. Gerald L. Pellet published a famous article titled “Eclipse Photography in the Digital Age” in the January 1998 issue of Sky & Telescope. Look for the article and apply his techniques. It might seem like an old article, but it’s a very useful one.
Get the best quality with calibration frames
In order to get better signal to noise ratio, I strongly recommend to also take calibration frames for all your totality images in case you need to merge them. This means you need to take flat-field, bias and dark frames.
A quick primer
Flat-field frames help you with getting an evenly illuminated field of view in the final image. Use a flat field panel or just shoot against a patch of clear blue skies. If you shot the corona through a photographic lens, use the same aperture for flat fields. Don’t change anything in the optical train of your system (don’t rotate your camera, for example). Around 80 flat-field images will make for a nice master flat.
For bias and dark frames, put the cap on your telescope or lens or remove the camera and put the body cap on. For bias frames, shoot a sequence of many images with the shortest exposure time available on your camera. Shoot around 80 of these, too. For dark frames, shoot a sequence of frames at the same exposure times used during totality. You shot the eclipse at 1 second, take 16 1 second dark frames. You also shot at 4 seconds? Take another set of 16 4 second darks. Do that for every exposure time used.
For all calibration frames, keep the same ISO setting that was used for shooting totality.
Automating your capture of totality with a computer
If you also want to see the eclipse (and, trust me, you want that) a good idea would be to automate the process of shooting the eclipse through a telescope or using a long tele lens. Otherwise, you will only see the eclipse on the display of your camera.
Luckily, there is some great software to help you automate everything. If you are a Windows guy, use Eclipse Orchestrator. The software costs $120 USD. If you use Mac, go for Xavier Jubier’s Solar Eclipse Maestro. This one is free, but I strongly suggest you to make a PayPal donation to Xavier if you decide to use his software. Eclipse Orchestrator and Solar Eclipse Maestro are pretty similar and both offer great results. There are some other options out there, like Astro Photography Tool or Eclipse Droid, but I have not tested them, so I can’t say anything about these two.
I will use Solar Eclipse Maestro. I have to warn you that both Orchestrator and Maestro are not that easy to use and you really have to test your scripts, sometimes through trial and error, until you get the desired result. If you are in a hurry and you don’t have the time to understand the software and the scripts you need, just take a few shots and spend most of the time watching totality.
To sum it up
- SHOOT RAW!
- Know the coordinates of your observing spot and when the important moments of the eclipse happen in that very spot
- Watch the weather and have at least one back-up plan
- Practice and rehearse your photography plan before the eclipse
- Make a gear checklist
- Use proper filtration during partial phases, but take filters off for totality
- Use semi-auto or auto modes for wide angle shots of totality
- Automate the photographing process as much as possible
- Use multiple exposure times for shooting the corona
- If something goes wrong with your gear during totality, just leave it and use whatever gear still works
- Watch the eclipse and enjoy
- Watch the eclipse and enjoy
- Don’t forget to watch the eclipse and enjoy
How am I, the author, going to shoot the 2017 eclipse?
I will shoot the eclipse with three cameras.
I will have an Olympus OMD E-M1 Mark II with an Olympus M.Zuiko 7-14mm f / 2.8 ED Pro lens on a fixed tripod. This will be used to shoot a sequence of the whole eclipse from Contact 1 to Contact 4. The camera will automatically take an exposure every 5 minutes. I will manually remove the filter before totality and add it immediately after. Except for these two moments, I will hopefully have no other interaction with this camera.
The second camera will be a Canon EOS 5D Mark III attached to a Pentax 75SDHF refractor. The telescope will be tracked by a Fornax LighTrack II tracker. Solar Eclipse Maestro will control the camera. The only difference from the photo below is that the telescope will be balanced with a counterweight on a different head. I will only use automation between C2-1 minute and C3+1 minute. I will manually shoot the partial phase; maybe a photo every five minutes. Between these partial eclipse shots, the camera will automatically take dark and bias frames to be used for calibrating totality photos.
My third camera will be a Canon EOS 6D with a Canon EF 17-40mm f/4L lens that I will use to take landscape shots during totality. I’m not planning to use the camera for more than one minute. Around Contacts 2 and 3, I will shoot some fisheye views of the approaching and departing umbra using a Canon EF 8-15mm f/4L lens.
My iPhone will record a video of totality and I will also have a GoPro timelapsing the whole event from Contact 1 to Contact 4.
My final advice: photography should not be your primary objective
Wish me luck and don’t do what I do, but do what I say.
I know that all of you want to take photos of the eclipse. I know that most of you overestimate your potential and will try to shoot as many cameras and lenses as you have available, even though this is going to be your first total solar eclipse.
I know it because I was there. And I failed. Partially.
Why do you I think I have no wide-field shots to show you? Because I did not use any automation software in 2006 and I had no time for the wide-angle shots, even though I thought I would have. The amount of excitement will grow so much during totality that you will forget what buttons to press. And, actually, it’s better not to press any buttons.
Don’t have photography as your primary objective for the eclipse. Viewing the eclipse is far more interesting. And it’s beyond amazing. Look at the eclipse as much as you can. In my opinion, it’s the most beautiful phenomenon happening in the sky; and I’ve seen pretty much everything that the sky has to offer. Total solar eclipses are special. And all are great; not just this one.