Nightscapes: Landscape Astrophotography Ian Norman ASSIGNMENT Your assignment is to capture a self portrait using the Milky Way as your background. You will map your location, get outside and capture a portrait of yourself using tools to bring out the milky way's image behind you, as well as your own silhouette. This assignment is great for expanding your understanding of light and how your camera captures is, as well as just creating a cool image. DELIVERABLE Upload your self portrait photo. A completed project includes:

A portrait of you A light source The Milky Way

Plan Your Astrophoto Shoot

1. Find a Dark Sky Location: Of all the things you will need to take an astrophoto, a dark location is probably the hardest thing to find, so that is what we will work on first. Unless you are lucky enough to live in a remote rural location with super dark night skies, you will probably need to make a trek out somewhere relatively remote in order to photograph the Milky Way. Don't be distraught if you live in a big bright city; with a little careful exploration, it's possible to find a place within a few hours away that will provide you with nice dark skies and a good view of the stars. Perhaps you have some place in mind already: maybe a national or state park that you have visited before or have been meaning to visit for some time. Maybe there's a place out in the woods where you've camped with your family, and you remember seeing more stars than you've ever seen before. These are the places that will make for great astrophoto locations. Let's learn about some tools that will help us find more prospective locations.

2. Finding Dark Sky Locations with Dark Sky Finder: The very first place to go when looking for a

new dark sky location is Jonathan Tomshine's Dark Sky Finder. Dark Sky Finder overlays a simple light pollution chart over a Google Maps interface. Take a look at Dark Sky Finder and use it to navigate to your home location. For example, here's what Los Angeles and the surrounding area looks like for me:

A light pollution map of Southern California from Dark Sky Finder

(www.jshine.net/astronomy/dark_sky/)

Dark Sky Finder is also available as a $1.99 app for iOS from the Apple App Store here. Unfortunately, there aren't any Light Pollution Map Applications that I can recommend for Android as of yet. If you live somewhere other than North America, consider visiting The night sky in the World homepage for a world atlas of light pollution. (Instituto di Scienza e Tecnologia dell'Inquinamento Luminoso (Light Pollution Science and Technology Institute of Thiene, Italy, www.lightpollution.it/dmsp/)) Unfortunately the data on this site does not have a geopolitical map overlay so you may need to compare it to Google Maps to understand what you are looking at. Once you've found your hometown, explore the surroundings for areas with lower levels of light pollution. In the case of Los Angeles, it looks like the best nearby areas are to the north in the green and blue zones on the map.

I highly recommend finding a location in the green, blue or black zones of the Dark Sky Finder map. This will probably mean that you will need to travel farther from cities, but it will make it much easier to see the stars, and your astrophoto results will come out much better. For example, if I go a little bit farther north toward Mt. Pinos, I will experience much darker skies than if I stay closer to Los Angeles. Search around on the map and take down some notes on the places near you with relatively low light pollution that might be suitable for your astrophoto shoot. ClearDarkSky.com: Another resource to find dark skies is the North American Clear Sky Charts on ClearDarkSky.com. There you can find light pollution charts available for most of North America. When you select a region, you’ll be brought to another map of that area covered in colored markers of different observational sites. Please note that some sites may not be open to the public. Either way, it should give you some more ideas about the locations available to you.

If you click on a site location, you can view cloud cover, sky darkness and other observational weather forecast information for the next two days and a guide for understanding the chart. This information will be helpful to review when you are about to set out to your dark sky location. Be sure to come back to the weather forecasts on ClearDarkSky.com later, a day in advance of your astrophoto shoot. Do some Google research about the areas available to you. You will want to find a good public location that is accessible at night. Often times the best locations are public campgrounds, state parks, national parks, bureau of land management lands and national forest lands, but you’ll have to do a little bit of sleuthing about the area to make sure that the location is open to the public after sunset. Your classmates and I will be interested in the location you select for your dark sky location. Once you have found a possible location, put it on your project page.

3. Put Your Dark Sky Location On Your Project Page: Let's start our Nightscapes Skillshare project

by clicking the "Start Project" button on the left side of the class page or by selecting "Start Your Project" at the bottom of this lesson page.

Now fill out some basic details about your project: Project Title: Enter your name and your dark sky location. Project Cover Photo (Optional): You can leave this one empty or, if you prefer, upload a

screenshot of your location from the Dark Sky Finder website. Project Workspace: Introduce yourself to everyone and tell us your prospective dark sky

location. Finally, select whether or not you would like your project to be publicly viewable, opt­in or out for peer feedback, and click "Create Project". Now that you have decided on a location for your astrophoto shoot, let's move on to the next section where we will learn about the best time to shoot.

4. Set a Date: Follow the Moon Phases Now that we have some ideas of where we can find dark skies, we need to figure out when the best time to view the stars will be. The important thing here is the phase of the moon. Moon Phase: On nights with a full moon, the moon will be in the sky for the entire duration of the night and will make it impossible to see the Milky Way. This means that for the best results, it’s better to plan our astrophoto shoot some time between the third quarter and first quarter of the moon calendar, ideally during a new moon. The closer the date you choose is to the new moon, the more time you will have during the night with dark moonless skies.

The best time to plan your astrophotography shoot is between the third quarter and first quarter, ideally during a new moon.

5. Record Moon Information: Check timeanddate.com for moonrise and moonset times and percentage illumination of the moon in your area. For example, on September 12, 2013, in Los Angeles, it looks like the moon is going to be at the first quarter (54.4% illumination) and will set after midnight on September 13 at 12:20am. This means that the darkest skies will be a bit after 12:20am until just before 6:35am when the sun will rise.

Remember that there might be more convenient times later in the month. You might need to wait a couple weeks until it’s closer to the next new moon. Once you have selected a date based on the moon phase, record the date and any important moon information like moonrise, moonset, sunset and sunrise on your Nightscapes Skillshare Project Also remember to check the weather forecast for your location a few days prior to your visit to make sure that you will have clear skies. Now that we have a prospective location, date, and moon information, let's find out more about what the night sky will look like in the next section.

6. Understand Where to Find the Milky Way and Important Constellations. Our night sky cycles throughout the year. Similar to how the weather changes with each season of the year, the December sky and the June sky are distinctly different from each other. Some constellations are only readily visible in December while others are only readily visible in June. In order to familiarize ourselves with the night sky on our astrophoto date, we will use an application called Stellarium.

Stellarium is a free open source planetarium application available on Mac, PC and Linux. Download Stellarium here.

You can also get a paid version of Stellarium Mobile for Android and iOS. However, keep in mind that this lesson is written for the desktop application. For additional learning on how the night sky changes over the course of the year, check out the additonal resource called Planetary Movement and the Seasons of the Night Sky. Let's get started with Stellarium to predict what the night sky will look like before we go out.

7. Open Stellarium and Set Your Location: Stellarium may give you a warning when opening stating "Stellarium cannot be opened because it is from an unidentified developer." If this is the case, right­click or command­click the Stellarium icon in the Applications folder and select Open from the option menu instead. You'll get another warning but this time, you'll have the option to "Open" the application. Open Stellarium and set your location by hovering over the left edge of the window and selecting the compass rose icon labeled “Location window” or press F6 to open the Location window. It also might be helpful to exit fullscreen mode by pressing F11 or clicking the fullscreen mode button on the bottom toolbar. This will allow you to switch back and forth between Skillshare.com and Stellarium. In the Location window, search for and select your location. You can also check the box “Use as default” to mark this location for next time you open Stellarium. Here I’ve selected Los Angeles, United States, Earth. Close the Location window when you have finished.

8. Set Your Astrophoto Shoot Date in Stellarium: Next, set the time and date to approximately the

time and date of your prospective astrophoto shoot by hovering over the left edge of the window and selecting the clock icon labeled "Date/time window" or by pressing F5. Now you can enter the time of your prospective shoot date. Here I’ve entered 12:20 AM on the morning of September 13, 2013.

Also, try advancing or reversing the time in hourly steps to see how the night sky changes with Earth’s rotation over the course of the night. Feel free to close the Date and Time window when you have finished.

9. Increase the Intensity of the Milky Way in Stellarium: The default brightness of the plane of the Milky Way in Stellarium simulates what it looks like with the naked eye, which is not very bright. Luckily, we can change the intensity of the Milky Way to make it easier to see. This will be very helpful in deciding where to point our camera once we are out taking photos.

Start by hovering over the left edge of the window and selecting the speech bubble icon labeled “Sky and viewing options window” or by pressing F4 to open the View window. When the view window is open, choose the leftmost tab labeled “Sky” and under the “Stars” section, increase the “Milky Way brightness” option to about “6.0” or higher. Close the View window when you are finished.

10. Explore Your Night Sky in Stellarium: To navigate the night sky in Stellarium, click and hold your

left mouse button to drag your view to other portions of the sky, left­click on night sky objects to see information about them, and scroll to zoom in and out (or use "/" to zoom in on a selected object and "\" to zoom out). You can also right­click to clear the selection and hide the information. Try out the different view options available by hovering over the bottom edge of the screen. I highly recommend turning on the following options:

Constellation lines [C] Constellation labels [V] Ground [G] Atmosphere [A] Cardinal points [Q] Planet labels [P]

11. Find Visible Constellations Along the Milky Way’s Galactic Plane: After you have explored the

night sky a little bit, we will want to use Stellarium to take note of the constellations along the Milky Way’s galactic plane. The galactic plane is the silvery cloud that stretches across the night sky and this is what we will be most interested in photographing. In general, the brightest part of the galactic plane, the galactic center, is most visible near the constellation Sagittarius in the months closest to the June 21st solstice. As the year approaches the December 21st solstice, we can instead see the so­called “galactic anti­center” which is around the constellation Orion. Again, for additional learning on how the night sky changes over the course of the year, check out the additonal resource called Planetary Movement and the Seasons of the Night Sky. In Stellarium, look for any of the below constellations that lie along the galactic plane that will be visible on your astrophoto shoot. The constellations that are visible will differ by date and time but any of them will help you find the Milky Way galactic plane.

12. Constellations that lie along the Milky Way’s galactic plane: Sagittarius Scorpius Scutum Aquila Cygnus Cassiopeia Perseus Auriga Orion Canis Major

For the particular date and time that I chose, Stellarium shows that the constellations Aquila and Cygnus will be visible to the West. This is where I should be able to see the Milky Way and this is the direction in which I will point my camera when I go out to make astrophotos. It looks like I will also be able to see the bright stars of the Summer Triangle: Altair, Deneb and Vega. Take note of the constellations that are visible along the Milky Way galactic plane. Here, Aquila and Cygnus are visible along with the bright stars of the Summer Triangle: Altair, Deneb and Vega. Depending on the time and date that you chose, you may have to wait for a particular time of night before the Milky Way galactic plane is above the horizon. If this is the case, use the Date and Time panel to find out when the Milky Way will rise.

I suggest taking a screenshot of your night sky view and putting it on your Nightscapes Skillshare Project Page for later reference: To make a screenshot:

Mac: Command+Shift+4 and drag a box around the part of the screen you wish to screenshot. Your screenshot will be saved to the Desktop.

Windows/Linux: Alt+Print Scrn and then open Paint or a similar program to paste and save the screenshot.

We’ll also want to record the important information that we learned from Stellarium including:

Cardinal (compass) direction to look for the Milky Way (North, East, South, West). Important constellations along the Milky Way plane Notable bright stars

13. Download a star chart app for your smartphone: If you have already familiarized yourself with the night sky on Stellarium, you should already have a decent idea of where the Milky Way will be in the sky on the night of your astrophoto shoot. If you picked a dark enough location, it should be even easier to find the Milky Way because you should be able to see it with your naked eyes. But even on nights with excellent views of the Milky Way and clear dark skies, it can still be difficult to figure out where to point your camera. To make it much easier, I highly recommend that you download a star map app to your smartphone.

I already mentioned the excellent Stellarium app for Android and iOS. There are a number of other options such as Google Sky Map for Android, Night Sky Lite for iOS or Star Chart for Windows Phone. All of them are easy to use tools for finding the important constellations along the galactic plane of the Milky Way. An app store search for "star chart" should give you plenty of options to choose from. Now that we've reviewed Stellarium, figured out what time the Milky Way will be visible, and noted some important stars and constellations, we should be ready to gather our gear before our astrophoto shoot.

14. Make a Gear List: Now that we have a location, date and time, and we have familiarized ourselves with what our night sky will look like, we are ready to prepare our gear. Let’s gather our photography tools and make a list on the project page. This has two benefits:

You will have a nice checklist of your stuff for when you venture out to take your first astrophotos. You don’t want to forget anything.

Everyone else will be able to see what gear was used to make your photographs which is helpful for learning and feedback.

The bare essential items on this list were already in the pre­requisites for the class so you should already have them on hand but I’ve also listed additional important items that you should consider bringing on your astrophoto shoot. Essential Camera Gear:

Digital SLR or equivalent Wide Angle Lens Tripod Headlamp or Flashlight

Other Helpful Items: Extra memory cards

Extra camera batteries Extra headlamp/flashlight batteries A small roll of masking, electrical or gaffer’s tape Warm clothes and comfy shoes for walking around at night A smartphone with a star chart app A tent and sleeping bag if you are camping Snacks and caffeinated drinks to help you stay awake String or an extra shoelace (more on this one later) Intervalometer or Timer Remote

Now let’s list our gear on the Nightscapes Skillshare project page. So far we have covered how to find a dark sky location, what time to schedule your outing, where to find the Milky Way, and what gear to bring. Your Skillshare Project Page should be a good guide to reference before you travel to your shooting location. Now that we have everything we need, let's move on to the next class unit where we will learn about how to set up our equipment at the photo location.

Set Up Your Gear

1. Travel to and Explore Your Location: In the last unit we prepared everything we needed for our astrophoto shoot. Now it’s time to venture out to our location to make our first astrophotos. I recommend that you try to arrive at your location before sunset. This will allow you some time to see the area in the daylight and figure out where everything is. We need to remember that it’s going to get really really dark, and we want to make sure that we are comfortable with the location. This is also a great opportunity to take photographs in the daytime with your camera and familiarize yourself with the view through your lens. The best time to photograph landscapes while the sun is out is usually about 1 hour before and until sunset. To photographers, this is known as “Magic Hour.” Think of this time as a dress­rehearsal for your astrophotos. The landscape will be the same at night, only dark. Since it’s much more difficult to roam around in the dark, this is the best time to pre­visualize your photos and figure out where the best spots will be once the sun goes down. Get comfortable. Enjoy the sunset.

2. Find the Milky Way Galactic Plane. Once the sun goes down and the stars start to appear in the

sky, we will want to anticipate the location of the Milky Way galactic plane.

3. Activate Night Vision Mode. Since it’s getting dark, you will want to lower the screen brightness of your phone and camera all the way to the minimum to prevent the screen from ruining your night vision. Some star chart apps also have a “night vision” mode that turns all of the screen features red. If your app has this feature, be sure to enable it. Finally and most importantly, this is also a good time to switch our headlamps to the red night vision mode as well. Red light won’t affect our vision as much as white light and will allow us to see the stars better.

4. Locate Your Important Constellations: Remember the constellations that we took note of in

Stellarium when we were planning? We’ll want to use our smartphone’s star chart app to help us find those constellations. Most smartphone apps allow you to use the phone’s built in accelerometer and compass to point the phone at the sky to match what you are seeing with what is on the phone.

When I was planning my astrophoto shoot, I recorded the important constellations Aquila and Cygnus and the bright stars Altair, Deneb and Vega in my project page. Find your important constellations in the sky to find the Milky Way galactic plane. With a little patience, you should be able to make out your important constellations and see the silvery cloud of the Milky Way. Be patient if you have some initial trouble getting your bearings on the night sky. Even though viewing conditions for astronomy and astrophotography are much better with dark skies, sometimes the constellations are a little bit more difficult to see because there are so many other stars in the sky. I recommend locating the brightest stars first and then referencing those stars in the star chart. If you don’t have a smartphone with a star chart app available, don’t fret. Just look roughly in the compass direction that you noted when we were planning. You may just have to let your eyes adjust to the darkness until you can make out the Milky Way with your eyes.

5. Set Up Your Camera for Astrophotography: Now that we know where to look in the night sky, it’s

time to set up our camera and tripod specifically for astrophotography. There are also some menu settings in your digital camera that we will want to set to help us achieve the best results.

6. Deploy your Tripod for Stability and Composition: Many tripods allow you to change the angle

of the legs to a wider stance to bring the tripod lower to the ground while increasing its stability. Often, the lower perspective can give you a more interesting composition. Consider the different possibilities in your shot and choose the deployment that gives you the best combination of stability and composition. Also, many tripods have a hook on their center column to allow you to hang a weight. The extra mass of a hanging gear bag or sack of rocks can help dampen vibrations in your tripod, especially if there is wind. If it’s really windy, you may also find it necessary to tie up your camera strap around the tripod center column or remove the strap altogether to prevent it from catching the wind and causing vibrations.

7. Set your camera to Manual Exposure Mode [M]: Manual exposure mode will allow us to set the

shutter speed, aperture, and ISO sensitivity for the camera. Manual mode will also usually enable you to select more advanced features like RAW file recording and long exposure noise reduction, depending on the camera.

8. Enable RAW recording mode: RAW image files contain more data than JPEG files and thus allow

for greater flexibility in post­processing adjustments. Since we are shooting in really dark conditions and may have to underexpose compared to normal photography, we want to preserve as much image data as possible. If you wish to use your photographs right away without processing, consider shooting in RAW+JPEG mode.

9. Enable Manual Focus Mode: The Manual Focus (MF) setting may be a switch on your lens or

within the camera menu depending on the model and type of camera. It’s very difficult to autofocus on stars so we will need to focus manually using your camera’s Live View mode. There are also some other alternatives for focusing in the dark that we will discuss later. For now, keep everything manual.

10. Enable Long Exposure Noise Reduction if Available: Long exposure images are susceptible to

residual heat noise. This is usually heat energy from the internal electronics of the camera (such as the CMOS amplifier) or from the environment. The heat energy gets mistaken as light energy by the

camera’s sensor and it shows up as noise in your images. Usually heat noise looks pink or red in your images.

Enabling “Long Exposure Noise Reduction” will reduce heat noise on your photos by taking a second photograph without opening the shutter to record what’s called a “dark frame” and then subtract the noise data from your image. Note, however, that this will usually add additional wait time to each exposure before you will be able to use your camera again for the next exposure. Also, you may find that if it’s relatively cold outside, or you are using a newer model camera, noise levels may be low enough that you will not need to use this feature. Sometimes it’s not worth the extra processing time that this feature requires although it is very helpful under most circumstances. Some models of camera do not have this feature. If your camera does not have long exposure noise reduction, refer to the Additional Resource: “Reducing Noise” for other methods of effective noise reduction.

11. Activate the Self­Timer: We will be using long exposures for our astrophotos (about 15 to 30 seconds) so we will need to make sure that the camera and tripod are as still as possible. Sometimes pressing the shutter button will be enough to shake your camera.

An easy way to prevent this is to use the built­in self­timer mode. This will give us 2­10 seconds to let any vibrations in the camera­tripod setup to settle before the shutter releases. An alternative to the self­timer is to use a remote shutter release, wireless remote, or intervalometer to trigger the shutter without touching the camera.

12. Set White Balance to Auto (AWB): The white balance usually varies a lot for astrophotography.

Sometimes stray moonlight can make your photo appear blue while other times light pollution can make your photos appear yellow or orange. There's even an atmospheric phenomenon called airglow that will turn your photos green. Since we are recording our images in RAW, we can compensate for the changes in white balance later in post­processing. Auto white balance will do a reasonably good job at compensating for the changes in white balance for now.

13. Enable Live View: The feature that will help with framing and focusing your camera in the dark is Live View mode. Live View allows you to see through the lens via the camera’s LCD. Not all DSLRs have a Live View feature. If yours does not, you’ll need to be extra diligent to maintain your night vision so that you can frame up your photographs using the optical viewfinder eyepiece. If you are using a mirrorless camera, you will already be using an LCD screen to frame up your shots. That covers the most important things to set up before you start making exposures. Continue to the next unit to learn how to make your first exposures.

Astrophoto Exposure

1. Make Your First Exposure: Before we worry about precisely focusing, we should point our camera at the sky (be sure to frame up the Milky Way now that we have found it), dial in some initial exposure settings, set the focus to infinity, and take a test shot. Make sure your camera is set to Manual Exposure Mode. The settings recommended below are probably nearing the extremes of what your camera can do depending on the make and model of the camera you have. Note, however, that these settings might not be the best for the final image, but they are a good start and should allow us to see detail in the Milky Way for framing.

We’ll try these first and adjust based on the results. I'll first give you some standard settings and then talk about why these settings are desireable for astrophotography.

2. Standard Exposures for the Milky Way: The cool thing about the Milky Way is that it’s always the same brightness. So if there are no other light sources such as light pollution or moonlight, we can usually use the same exposure every time. Below are some standard exposures for the Milky Way. I suggest starting based on the lowest f/number your camera and lens can achieve and then adjusting accordingly.

Standard Exposure Values for the Milky Way*

f/1.4, ISO 1600, 30 seconds f/2.0, ISO 3200, 30 seconds f/2.8, ISO 6400, 30 seconds f/3.5, ISO 10000, 30 seconds f/4.0, ISO 12800, 30 seconds

Note that all of the exposures on the list above are the same Exposure Value or brightness. They rely on the rules of reciprocity: a higher f/number requires compensation with a more sensitive ISO. It's possible that your camera may not be able to reach a high enough ISO to match the chart. If that's the case, just set the highest ISO possible. Remember that factors such as light pollution or moonlight may force you to use a slightly different exposure. If your image is too overexposed or underexposed, first try adjusting your shutter speed or ISO to compensate. See the next class unit "Adjust Your Exposure" for more information.

3. Shutter Speed: 30 seconds: Shutter speed is the amount of time that the shutter stays open to expose the sensor to light.

For most daytime shooting we usually want a short shutter speed such as 1/200th of a second to prevent motion blur. For astrophotography we want the exact opposite: a long shutter speed to gather as much light possible. 30 seconds is usually the longest shutter speed that most DSLRs will allow you to select without an accessory intervalometer or use of the camera’s “Bulb” mode.

We want a relatively long shutter speed because it’s really dark and the Milky Way is very faint. The longer the shutter is open, the more light the sensor will be able to collect and the brighter our photograph will be. 30 seconds also just happens to be just about the longest shutter speed that we can use on a wide angle lens without causing the stars to “trail” in the photograph due to Earth's rotation. Below is an example of how the stars start to trail for exposures longer than 15 seconds. We will talk more about preventing star trails later in the next class unit "Adjust Your Exposure."

4. Aperture: The lowest f/number possible: Aperture is how wide the opening of your lens is when light passes through. Aperture literally means “hole” or “opening.” It is probably the most misunderstood of all the exposure settings on a camera, probably because aperture is expressed in f/numbers, sometimes called f­stops. An f/number is the ratio of the focal length of the lens to the diameter of the lens opening. The lower the f/number, the larger the opening. Low f/numbers like f/2.8 or f/1.4 mean that the opening of the lens iris is larger, allowing more light through. Higher f/numbers like f/8 or f/11 mean that the opening of the lens iris is smaller, allowing less light through.

This number is a direct measurement of what photographers call “lens speed” ­ the lower the f/number, the “faster” the lens.

Diagram of decreasing apertures, that is, increasing f­numbers, in one­stop increments; each aperture has half the light gathering area of the previous one. The lowest f/number you can set will differ by different camera lenses. Most 18­55mm kit lenses only go as low as f/3.5. I highly recommend using a “fast” lens with a maximum aperture of f/2.8 or lower if you can. Faster lenses and low f/numbers will gather more light and allow us to see more detail of the Milky Way in our image. See the Additional Resource "Lenses for Astrophotography" to learn more about how to pick a great lens for astrophotos.

5. ISO: High ISO: ISO stands for "International Standards Organization." In digital photography, ISO is a standard measurement of sensitivity to light for camera sensors. The most commonly used standard ISO settings for daytime photography are ISO 100, ISO 200, ISO 400, ISO 800, and ISO 1600. Each ISO step (or stop) is a double of the previous ISO number. ISO 200 is twice as sensitive as ISO 100 and ISO 400 is twice as sensitive as ISO 200 and so on. Most modern DSLRs can reach at least ISO 3200, with some newer models achieving sensitivities higher than ISO 25600. Because the rest of the stars in the Milky Way are relatively dim to us relative to sunlight, we will almost exclusively use ISOs higher than ISO 1600 for astrophotography. Some cameras have an extended or expanded ISO range that goes beyond the standard range of sensitivities, they are usually designated with an ‘H’ or ‘Hi’ for “High Sensitivity.” For the purposes of preventing too much noise in your astrophotography, avoid using the expanded ISO settings if possible. High ISOs will boost the gain on the sensor and make an image brighter though will also increase noise levels. Because of this fact, we should use the lowest ISO that our lens f/number will allow.

6. Set the focus to infinity for now, fine focus later: For this test shot, we should just focus the lens

at infinity for now. We will more precisely adjust our focus using Live View later. To set the focus to infinity, rotate the focusing ring of the lens all the way to the left until the distance mark is on the infinity symbol. Some camera lenses do not have any distance markings for the focusing ring. If your camera has no infinity mark, just rotate the focus ring all the way to the left and then just a touch back. We will review more advanced methods of focusing in the next section.

7. Take your test exposure: Now that we have our shutter speed, aperture, ISO and focus roughly

set, we can take our first test exposure! Frame up the portion of the sky where you found the Milky Way and take your first shot! Remember: If you enabled "Long Exposure Noise Reduction," the camera will expose the scene for 30 seconds and then take another 30 seconds for the dark frame, so you will need to wait a full minute before your camera is ready to shoot again. Here’s what my test exposure looks like:

Canon EOS T2i, 18­55mm lens at 18mm f/3.5, ISO 6400, 30 seconds

After you take your first exposure, you will want to review the detail in the image by using the magnify function while reviewing the image. The first thing we are concerned with is focus. In the example image, we can see some detail in the Milky Way, but it looks like our image is a little bit out of focus. Let’s learn some techniques on how to focus more precisely in the next section.

8. Focus in the Dark: There are several methods to help us focus in the dark. Usually we cannot just set the focus to infinity and forget about it. The following methods are listed in order of preference with the easiest and most accurate method first. Sometimes it’s helpful to set your focus and then tape the focusing ring in place to prevent it from shifting between shots.

9. Bright Star with Live View: Using manual focus and Live View mode is the most accurate method

of focusing on the stars. Point your camera toward the brightest star you can find in the sky. Try to center the star in the viewfinder. When the star is centered, enable Live View and use the magnification button to zoom the view on the bright star. Now you can adjust your focusing ring until the star is as small and as bright a point as possible.

10. Distant Light: If you cannot see any stars in the LCD, first check that you set your exposure as

described in the previous section (30s, lowest f/number, high ISO). If you are still having difficulty seeing any of the brightest stars, try focusing on a light at a distance. You can make your own light in the distance with the method below.

11. Headlamp/Flashlight: This method can be an easy way to get your camera to focus in the dark but

requires some legwork if you don’t have a helping hand to hold the flashlight for you. It’s often best to place a light source at a distance of about 100 feet or so and focus on the light source. This distance should be far away enough that it will also achieve focus on the stars. Have a friend hold it to make things easier. Your light source may be bright enough to use autofocus, but I still recommend manually setting the focus on the screen with the magnification function so that you are completely sure of your focus. This method can also be helpful if instead you wish to focus on a closer foreground object such as a tree or person rather than the stars.

12. Trial and Error: Manually Set and Check Focus: This is the method that you will likely need to

use if you do not have a camera with a Live View function and have no luck autofocusing on a distant light source. It’s exactly as it sounds: set the focus as well as you can manually, take a photograph, and review it under magnification. If it’s out of focus, adjust the focus a little bit in one direction and take another photograph and review it again. Repeat until you are convinced that you have achieved sharp focus. This is a rather time consuming method and requires much patience. Regardless of the method of focus you decide to use, always use the magnify function on your screen preview to check the focus. Don’t take the initial thumbnail at face value. Once your shots are in focus, you can use a piece of tape to hold the focus ring and prevent you from accidentally bumping the focus.

13. Adjust Your Exposure: For one reason or another, we may need to adjust our exposure settings

from our initial test settings. The settings we initially set should be a good start, but we may have issues with overexposure, noise, or star trailing, all of which will depend on things like light pollution, your camera, the temperature, and the lens that we are using. The best way to evaluate your exposure is to use the histogram view on your camera.

14. Enable the Histogram: You can usually enable the histogram in playback review by pressing the

“Info” or “Display” buttons or by pressing the up or down arrows when in playback review mode. It differs greatly from camera to camera, so review your camera’s manual if you cannot figure out how to enable the histogram. Histogram is just another word for graph. In photography, the histogram is a bar graph of the luminosity or brightness of the image. The left edge of the histogram represents pure black and the right edge of the histogram represents pure white. This lets us evaluate whether

or not our image is overexposed or underexposed. When we expose the camera’s sensor to light, we are recording light signal. In general, it’s better to have a brighter image because it usually means that we have more overall signal in our image. The more signal, the better signal­to­noise ratio. A better signal­to­noise ratio means that we will have a cleaner image.

We want lots of light for more signal but there is such a thing as too much signal. At a certain point, an image can be so overexposed that the sensor is completely saturated and is forced to “clip” the data, making the image look blown­out bright white. We can prevent this by reviewing the histogram of the image and making sure that the data on the graph does not flow over the edges of the graph. The same thing applies to underexposure. Underexposure is generally much worse than overexposure. This is because an underexposed photo by definition has less light signal stored in it. As a result, it is much harder to “recover” an underexposed photograph in post­processing than it is to recover an overexposed photograph.

15. Overexposed Images ­ Reduce ISO: If your image is totally blown out and overexposed, the first

thing you should do is reduce your ISO. Reducing your ISO will reduce the overall exposure brightness and also lower noise levels in your images. I rarely need to use an ISO higher than ISO 6400 for my final images.

16. Underexposed Images ­ Reduce f/number or Increase ISO: If your images are super black and

underexposed, reduce your f/number first. Remember that f/2.8 or lower is preferable if your lens is capable. If you’re already at the lowest f/number of your lens, you may need to increase your ISO to brighten your exposure. Finally, if your ISO is also as high as it goes, and your images are still underexposed, you may wish to try using the “Bulb” exposure mode on your camera to take a photograph longer than 30 seconds. Remember, however, that shutter speeds longer than 30 seconds will usually start to show star trails due to the rotation of the Earth.

17. Star Trails and Focal Length ­ Reduce Your Shutter Speed: When you magnify your images

upon review, you many notice that the stars look like lines or trails across the sky. Star trails are caused by the rotation of Earth. For any given angle of view, or any given lens focal length and sensor size, there is a certain amount of exposure time before Earth will have rotated enough to start to smear or trail the stars across your image frame. You can check whether the stars are trailing by reviewing the image and zooming all the way into the detail. Start with the recommendations on the image below for your lens and sensor size, and then adjust accordingly. If there is too much trailing, just reduce your shutter speed a little bit. Remember that you may need to compensate for the reduced brightness of a shorter shutter speed by increasing your ISO or lowering your f­stop number. Note: for 4/3" sensor cameras, multiply your lens focal length by 2x and refer to the full frame recommendation above. Once you have determined the maximum shutter duration with no star trailing for your lens or focal length of choice, remember it. That shutter duration will always work for that particular lens on that particular camera. For instance, at 18mm on my APS­C cameras, I have found that 20 seconds works every time.

18. Adjusting for Noise: Remember to use your camera’s “Long Exposure Noise Reduction” function if

it has it. More generally, reducing the ISO is the first way we can reduce noise. However, we may find that this will underexpose our images too much unless we can compensate by reducing the

f/number or increasing our shutter speed. If you are still getting overly noisy images, check out the additional resources in Unit 5 for more information on noise reduction methods.

Composition Techniques

1. Compose for the Landscape: A night photograph is much more interesting when you can combine the beauty of the night sky with the beauty of the landscape. It’s one thing to see an intricately detailed image of the Milky Way’s galactic center, but it’s a whole different experience seeing Earth in relation to the rest of the galaxy. Use elements in your surroundings to make your photographs more interesting. Consider different perspectives by changing your tripod position and height, and don’t forget to include any unique features of your landscape in your photographs.

2. Geometric Composition Rules: There are many rules that photographers follow to guide their

compositions. Most of them work by aligning elements in your photograph with prescribed lines or intersections in the frame. The most commonly used rule of composition is called the Rule of Thirds. If you are uncertain of how to start composing your astrophotos, I highly recommend beginning with the Rule of Thirds. You will find that it's very simple to follow and can greatly improve your results.

3. The Rule of Thirds: To apply the Rule of Thirds, imagine splitting your frame into horizontal and

vertical thirds, and place the horizon line or other elements of your photograph along the resulting gridlines. Use the intersections to place important subjects. In the above photo, the horizon is placed along a gridline so that the foreground fills the bottom third of the image, and the people are placed at one of the intersections.

4. Positive and Negative Space: A concept called positive and negative space was also used when

composing the above photo. The people are positioned in a way that creates a strong contrast between their silhouettes (positive space) and the sky (negative space), making for a more compelling photo that emphasizes the shape of the subject. Since you've already set your exposure in the last unit, you can now focus solely on composition. Play around with a variety of ideas and try to showcase the unique traits of the location that you chose.

5. Paint with Light: The headlamp that you have can be used for more than just helping you see in

the dark. You can also use the headlamp to fill your foreground. This is a simple technique called painting with light, and it’s as simple as sweeping the beam of your headlamp or flashlight toward elements of your foreground while your camera is exposing the image. If you use the self­timer in your camera, it should give you ample time to walk out into the frame or toward the foreground elements in your photograph before the shutter opens.

6. Controlling Brightness of Light Painting: The easiest way to control the brightness of your light

painting is to count. Just count the number of seconds that you have your light turned on. Start with about 5 seconds. If you wish to change the brightness of the lighting, doubling the duration to 10 seconds will double the brightness. Halving to about 2.5 seconds will halve the brightness. Different headlamps and flashlights will have different intensities, so the the key here is to experiment.

7. Capture a Nightscape Self Portrait: Here’s what we’ve all been waiting for: a photograph that

combines the landscape, the Milky Way and portraiture all into one. Try taking a few self portraits with the following methods. You’ll need to set your camera to a 10­second self­timer or have a friend press the shutter button for you.

8. Simple Silhouette Self­Portrait: A first portrait to try is a Simple Silhouette. The easiest way to

make a silhouette is to position your tripod low to the ground and use the top two thirds of the frame for the sky and the bottom third for the ground. Using the self­timer to give you time, position yourself against the sky. Remember the Rule of Thirds if you are uncertain of how to frame the image and where to stand. Don’t forget to stand as still as possible while the shutter is open!

9. Painted Silhouette: You can also create a silhouette with your headlamp or flashlight. The trick

here is to face away from the camera and paint an object in front of you. This will create a nice bright feature against which you will be silhouetted.

10. Light Ring Portrait: You probably recall this image from previous sections of the class. One of the

optional items I suggested to bring on your astrophoto shoot was a string or extra shoelace. If you forgot to bring one, you can probably improvise by unlacing the shoes you are wearing! The setup for this photo is the same as the Simple Silhouette. But this time, try tying your headlamp or flashlight to one end of the string and spin it around in a circle to paint a ring around your body in the image ­ a really simple technique for an awesome effect.

11. Light Orbs: A variation on the Light Ring is the Light Orb. Rather than just spinning the light on a

string in one plane, slowly rotate your body around in a 360 degree circle while spinning the light to paint a sphere of light. This is a fun one for using your headlamp’s red night vision mode.

Processing Astrophotos

1. Process Your Astrophotography: For the following lesson, pick your favorite nightscape photograph or download an example RAW file to work with here. It's an Adobe DNG which should be compatible with most RAW editors like Adobe Photoshop Lightroom. For reference, this example photograph was made with a Canon EOS M and a 22mm lens from Joshua Tree National Park in California. Exposure settings were: 15 seconds, f/2.0, ISO 3200. RAW images are typically pretty flat­looking and require some post processing to make the photograph as high quality as possible. I personally recommend Adobe Photoshop Lightroom to process your photographs. It's the industry standard and only costs about $150. If you don't have Lightroom, you can download a 30­day trial from Adobe here. The RAW editor that came with your camera is probably just fine, too, but Lightroom will likely be easier to use.

2. Post Processing: The thing to keep in mind here is that less is more. If you push the exposure of

your photograph too much in post processing, you will often increase noise levels and reduce the quality of your photograph. For this reason, make your best effort to properly expose your photographs in the camera. There isn’t one right way to process your photograph, and my methods might not be best for your particular shot, but in general, you should focus on just five basic things:

White Balance Saturation and Vibrance Contrast, Levels and Curves Vignetting Correction Exposure and Brightness

3. White Balance: According to researchers at the University of Pittsburgh, the color temperature of

the Milky Way is about 4840°K.