Tag Archives: planning

Photo Pills Ultimate App for Photography

Originally Published Nov 29, 2013
Last Updated April 18, 2016

For me this app is why I have a smartphone.  It has a lot of features, which makes it one of the most inclusive apps out there for photography.  Even just one of their modules would make up the entire functionality of others apps.  You are essentially buying many apps in one since is has a plethora of functions and shortcuts. It is going to take a long time to master so do yourself a favor:  sit down with it for a while read up and explore.   First go to the section on learning and learn! Tapping and swiping allows you to switch dates, times, modes, and more. Getting the feel of the app without trying some critical calculation will put you in a better frame of mind.

Accuracy

Steven likes to point out that the app is only as good as the hardware it is built on, and I can attest to this. Steven’s iPhone 4 compass and accelerometer must be off – the sun and moon locations are wrong by up to 10 degrees (more than 16 moon diameters).  Inaccuracy seems to also be a problem with the 4s and the 5s there have been many complaints. The iPhone 5 seems to have better sensors.  See the Macworld article: Six Phones Can’t Agree on Magnetic North

While the Macworld article is the result of poorly conducted calibration, the important takeaway is that the app can only be as accurate as the environment you run it in and the hardware you run it on. It can’t be said enough: trust but verify. Then recalibrate and try again.  Bring your own GPS and compass to verify the accuracy. We are not suggesting to use the iPhone as a navigation device just an aid. Apple maps didn’t work out so well remember! We are suggesting that this can be a useful device for the visualization of photos or getting an idea of your compositions and bringing your most accurate tools to bear. If you’re fanatical about accuracy, like Steven you can also bring your compass, maps, GPS, planisphere (ref 123,) and sextant.  Ok, the sextant was a joke but I wouldn’t be surprised if he has one. Steven is crazy about accuracy in predictions.

Navigation Basics

Navigating the app is easy to get started. Start swiping and you will be unlocking all sorts of functionality.  At first you will be surprised by all of the hidden things you are doing.  For me the first time I opened it up I was like, Wow, what was that? What did I just do?  Once you begin to get a little more advanced you will start to realize you may not be remember the proper, tap, drop, swipe, handshake combination to get where you want to go.  Generally it will take some practice but let me give you some tips out to help.

More content dots – The dots in the image below are a symbol that shows there is more content on this topic available just swipe in the correct place to the left or right.

More Content Dots

The next page dots are sneaky because they blend into the background.  However, they can be found in the same general location so just look to see if they are there.

Transition between right and left pages by swiping seeing the more content dots.

Transition between right and left pages by swiping by paying attention to the more content dots.

Previous page button – Found in the upper left.  This button brings you back to the prior menu, usually. It can be helpful for getting around the app so don’t forget about it. Even when it says something strange, it usually is a “back” button – except when it is not there and is instead a “Done” button on the upper right.  There are also important buttons that appear in the upper right so when you are finished look up there for some important info.  Like what you ask? The save button often appears here – or at the upper right.

Photo Pills back button on upper left.

 

 

Changing your location or a value generally requires just a tap however in some cases it requires a tap and hold or double tap.  My solution try them all.  In the planner, the map will find have some icons you can tap (sometimes by accident).  Or save yourself a bit of hunting by finding the Learn page and reviewing the options described there.

The Photo Pills Menu in all of its glory

Photo Pills

The three main menus of Photo Pills.

 

What does every module Do?

Here is a short summary:

My Stuff

Plans – Where your Plans are saved.

Points of Interest – Local points of interest. Over 10,500 all over the world! Also has a search functionality.

Settings – Calculations are based in the units of measure you select, on the Camera body you select.   I would suggest starting here. Imperial and Metric are the options.

Pills

Planner – The Photographer’s Ephemeris (TPE)-like functionality. Is used for Sun and Moon alignment planning similar to what we cover in our Catching the Moon Webinar.  Mostly used for planning, as well as scouting, but has some nice sharing functionality which will help in the organization of scouted locations on the fly.

Planner looks a lot like another program I know

Sun – Detailed information about Sun rise, set,  Time to set Azimuth Elevation, Distance, Shadow Ratio, start of different twilights (Civil Nautical Astronomical), Magic Hours (Blue, Golden), Calendar, Augmented Reality, Seasons, and Sharing (Facebook, Twitter,  email, or save as an image).

Moon – Detailed information about Sun rise, set, Time to set Azimuth Elevation, Distance, Shadow Ratio, start of different twilights (Civil Nautical Astronomical), Magic Hours (Blue, Golden), Calendar (Phases each day), Augmented Reality, Distance (Perigees and Apogees), and Sharing (Facebook, Twitter,  email, or save as an image).

Exposure – Allows you to determine equivalent exposures, that is equivalent brightness using different settings. Determine equivalent exposures by changing shutter speed, aperture, ISO. Will also help you understand how a ND (Neutral Density) filter will affect the exposure.  This also calculates the change in EV value.

DoF – Is a DoF (Depth of Field) calculator using your current exposure settings, (Camera, lens, aperture, distance to subject, lens set up teleconverter status), a DoF table, augmented Reality, and Sharing (Facebook, Twitter,  email, or save as an image).

Hyperfocal – A table which shows at a given focal length (14mm) and a given aperture value (F/1.4) what distance everything is going to appear in focus (15 ft 4in) to infinity.  We talk about it a lot now you have no excuse for looking it up.

FoV – Is a Field of View calculator using your current camera, lens, and distance to subject, Camera orientation (landscape or portrait) to give field of view information.  You can also inverse this so you know where to stand or use Augmented Reality to see it in the phones camera.  Oh and you guessed it; share (Facebook, Twitter, email, or save as an image).  Also allows you to find equivalent FoV settings between cropped sensor cameras.  One application Steven recently used was to determine what focal length to use to fill his field of view with Mercury, Saturn, Comet ISON and Comet Encke (136mm).

Night – Includes 3 main features Night AR, Star Trails, and Spot stars. Night AR allows you to see the location of the Milky Way, the rise of the moon, and the direction stars will rotate. Aids you in the pre-visualization of how long your star trails would be. Inversely, it allows you to calculate how long it would take for the stars to form a specified arc in the sky.  Finally, under Night is Spot stars which calculates the shutter speed necessary to make stars appear as spots without the aid of an equatorial mount.  For an in depth article on this subject, see here.

Time Lapse – Allows you to calculate data about your timelapse before you art.  Information such as Event duration in real time and as a final product, FPS, total number of photos and the file storage necessary to capture the sequence on your memory card.

Learn

Help – In depth help on the app, tips on the menus and how to navigate, what buttons do what.  There is a lot.  After a quick stop at the settings then go over here. Check it out.

About– Learn about the developers, Contact the support staff, rate the app, applaude the team.

The Awesome Parts

The app is just so big that I am not going to be able to cover all of it in detail.  There are a lot of parts of the app I want to touch on.

The data –  The data on every tab is amazing and detailed.  You want the data on what phase the moon is in, data on when the phases are that month.  The data just does not stop, it is not just the Sun or moon tab it is on FOV or DoF tabs.  For a guy who does a lot of panos all of the hyper-focal, FoV info is impressive.  I LOVE ALL of this data presented in a logical, clear and concise way.  But, wait we want more data.

Augmented reality – This is one of the most useful parts of the app.  For my money this was the best tool to teach and help students visualize where the North Star is and where the Moon and Milky Way is going to rise.  The overlay on the scene is the magic that allows students see where the Milky Way will be because it is super-imposed on the live picture.  There is AR for everything Night, Sun, Moon, Depth Of Field… Yes, even DoF – not a preview, but an on screen indication about the range of the DoF setting.   In my experience the AR has been accurate and responsive however this has not been everyone’s experience depending on your phone hardware.  I am told the inaccuracy issues are due to the hardware not the software, but that is not going to stop the complaining.  Can you use if for any scouting?  Well that is highly debatable (Steven and I have had heated discussions about this).  We would love to have more data on the photogenic parts of the Milky Way (i.e. Sagittarius, is much more deep and milky than Cassiopeia but the current depiction is rough).  Location of Stars to aid in the orientation.  I personally don’t care about the size of the moon.  Steven would like to see the size be more realistic – it’s currently shown about 8 times its actual size. I can foresee problems with people with bad vision or people not patient enough to search for the moon (I know a lot of those, bad vision not the part about being patient). The on screen display (AR) also doesn’t show the GPS, exact angle of elevation, or exact compass direction – the data is drawn in grids that are increments of 10 degrees vertically and 12.5 degrees horizontally.

But I digress, the great part about AR is that it can help you see what might be possible, when might the moon be near that object.  You may still have to do the work over again because we have seen the predictions be as far off as 10 degrees if you rely on the phone hardware for compass direction.   

The moon is 0.5 degrees if you are running photo pills with a bad compass (bad hardware or just a bad calibration) The moon could be 20 moon diameters away in this photo (10 degrees / 0.5 degrees = 20 moon diameters). The moon would be out of this frame in that case.

The moon is 0.5 degrees if you are running photo pills with a bad compass (bad hardware or just a bad calibration) The moon could be 20 moon diameters away in this photo (10 degrees / 0.5 degrees = 20 moon diameters). The moon would be out of this frame.

 

Planner – It is not as good as I would have liked.  My main gripe was the small screen is difficult to navigate and to pinpoint the exact point where the alignment is going to be.  One thing is that there is elevation profiler which will allow you to determine what the height of the object is on the horizon.  Useful yes but useless if there is a huge building in the way.  It also currently doesn’t have ready access to a Topo Map so determining where there might be a hill in the way is not simple – unless, of course you are on site..  I like the share options, in the Points of interest tab you can export all of your points to a KMZ file you can open in a map editor (like Google Earth).   The win for me was the portability, I always have my phone so I can just scout whenever I see something interesting so I can come back later.

I can plan a shot where ever I am, unless I need the map and am not able to get a data connection, that is.  If I see something interesting, I can check for an alignment right on the spot.  I can figure out if it is possible then bring out the big guns for double checking.  I think this is one of the biggest advantages.

One thing that tripped us up… there are two AR modes in the Planner. The outer one – which is for “getting an idea” and the inner one that appears after you start a Find operation. The AR choice after selecting Find allows you to use AR to set the location of your desired target. Point the display and tap it to place the moon or sun where you want to capture it. Remember, though, that the moon or sun will be shown about 12 times larger than actual size.

To close this app is the most comprehensive and inclusive of features, some planned usability enhancements will definitely kick it up a notch.

Enhancements We’d Like to See

What we would like to see alignment prediction tool additions.  Photo Pills has so much. Now that we have seen what it is capable of we want more.  Serious, understatement there because, honestly we what a whole LOT more, and that’s not to say we hate the app – not at all. It still packs more punch than everything else we’ve looked at.  However, as noted, we would like to see more data in the AR and in the planner.  We would like to be able to take a photo of the scene and have the all relevant data overlaid on the same photo.  Further, we would like to have access to the meta-data burned into the photo.  When we share a plan, it doesn’t seem to include the elevation (altitude), azimuth (compass direction) and tolerance information. We are geeks we want to write scripts to sort and map that data, and track our exploits much like Spyglass.

There are a couple of little niggles in the interface that are annoying. Lines that don’t get drawn on the planner map, accidentally resetting the observer location by dragging our finger over the “set location here” icon while scrolling the map, and others.

If possible, we’d like to see an “enhanced accuracy mode” so that you can be 90% confident that the AR alignment that you are shown will indeed be within 0.5 degrees.

Even though of how we’d like to improve the visual interface… but hey, that doesn’t mean it doesn’t work well as is.

How Accurate Is The Application? Participate and Find Out!

We want to collect data from testing in many environments on many devices, not just from our own half dozen devices.  Please do the following.

  1. Play with PhotoPills a bit to be sure you understand it.  Go to the help menus and learn about the AR and other functions.
  2. Kill your compass app and Photo Pills (all apps preferably). This is to insure that you have a chance to calibrate.
  3. Start PhotoPills. Go to “Moon” make sure that “Info” has the current time (double tap the center of the Moon).
  4. Click on AR.
  5. Verify that the current date and time are correct in the upper left. If not, go back to Info and double tap the Moon or go into settings.
  6. If/when the phone asks, perform a calibration on IOS 7.0 and later you “roll a ball around”. Older IOS versions may ask you to wave the phone in a figure 8. Hold your phone normally (Portrait mode)
  7. Point the camera at the Moon. Obviously the moon must already be up in the sky for this test. You CAN try this using the sun instead, but that wouldn’t be good for your eyes or the phone unless the sun is just rising or just about to set.
    Once your target is in view select the “Action” button (lower right).

    • If you have a Twitter account choose “Twitter” and send your photo to @starcircleacade be sure to include #photopillstest and your iPhone version e.g. #iphone4 or #iphone5s and your ios version e.g. #ios703.
    • If you don’t have Twitter, please use email and send your photo to results@StarCircleAcademy.com
    • If you don’t have email available, you can save the image or post it to Facebook – just be sure to share it with us!
  8. Next turn your device 90 degrees to Landscape mode, spin yourself around a full 360 degrees (trying not to get dizzy), point the phone back at the target and repeat step 7.
  9. Super Extra Credit would be to take a photo of multiple iphones on a table all set to compass mode.

Please only send two photos one in portrait, one in landscape mode per each device you have Photo Pills on.   Thank you for your help! Also, please note that large metal objects (your car for example), computers, electronics and what-have-you will affect the accuracy of the compass. If you can move away from such things to do your calibration and take measurements that will help.

We will publish an update to this material once we get enough data to make some calculations.

Solar Eclipse… May 20th.

If this is the first you’ve heard of this event, it may be too late to be properly prepared to photograph it. The maximum occurs at around 6:33 PM for those in the San Francisco Bay Area (and at most a few minutes before or after that for everyone else in California).  Be sure to go out at least 5 minutes prior, though. To get a more exact time, click the map below then double click on your location. Don’t let the date of May 21st fool you! The time shown will be “UTC” the time in *London*. Those in the Pacific Time zone must SUBTRACT seven hours from UTC.  If the time of maximum is listed as: 2012/05/21 01:33:24 then the Pacific time is seven hours EARLIER or 18:33:24 (6:33 PM).

What NOT To DO

  • DO NOT look at the sun even during the maximum period. This is an Annular eclipse so much of the sun will NOT be covered.
  • If you MUST see the eclipse make sure you have proper eye protection. A camera obscura may work. A Camera Obscura is a box with a pinhole in it that allows you to observe the sun by looking in through the SIDE of the box at the projected image (not through the pinhole!)
  • For many more NOTs see here.
  • Here is one “not” illustrated for you.  For this I took a pair of low power binoculars held the safe solar filters against the eyepiece and pointed the unit at the sun. See the pinhole burned through the plastic… imagine that is your eye, now blinded.  Don’t Do It.

    What NOT to Do! See that hole burned by the sun? That could be your eye!

    Here is a page describing how to observe safely, including building a pinhole “camera obscura”.

For more information about Solar Filters please see my “Solar Filters” blog entry.

Alignment (Part 2 of 2)

If you are finding these articles useful, please spread the word. Share us, Tweet Us, Digg us. Like us on Facebook. And if you would like one on one instruction please consider a Star Circle Academy Workshop. Now back to your regularly scheduled program.

In a previous column: Alignment Part 1 of 2, I touched upon the many elements that complicate capturing the moon near an object on the horizon. Here they are again for consideration:

  • The amount of moon illumination changes daily.
  • The moon’s rising and setting location must be accurately calculated – and it changes daily.
  • Exposures to capture moon detail require the right amount of foreground illumination.
  • The site chosen must have an unobstructed view of the sky in the desired direction.
  • To get a “big moon” it is necessary to get far enough away from the foreground.  If too close, depth of field problems may arise.
  • A well supported telephoto lens is required.
  • Capturing a shot of the moon near the horizon means the atmosphere must be relatively clear of clouds, dust and haze and when very low in the horizon there is more atmospheric distortion.

Figuring out how to tackle the moon location is computationally challenging. Fortunately with the internet there are many free resources to aid in this endeavor. And more fortunately, there is one tool which is almost ideal for the task: The Photographer’s Ephemeris.

We will address the problems step by step.

  1. Obtain the appropriate camera gear.
  2. Identify a suitable target.
  3. Calculate how far away we want to be from the target.
  4. Identify possible vantage points to shoot that target.
  5. Verify (visually, if possible), that the target is viewable from the vantage point and that there is sky behind our target.
  6. Verify that the moon will pass near our target and at an opportune time of day.
  7. Determine how high in the sky the moon should be.
  8. Fine tune the location to be sure the geometry is correct.
  9. Pray for good weather!

The camera gear element of the puzzle is easy: get the longest telephoto lens available. 2,400 mm will work great with a 35 mm (full frame) camera. I do not have anything that big (or expensive), so I use a 70-200 mm lens with a 1.4x extender on a 1.6 crop factor camera.  That effectively gets me 200 \times 1.4 \times 1.6 = 448 mm focal length. The “short” focal length of 448 millimeters means I can not fill my frame with the moon – it would take 32 moons laid out in a grid. Getting more foreground in the shot creates more opportunity for an arresting image however. Besides, those really big lenses are not only expensive, but unwieldy. In fact, they call them telescopes! Working with a crop camera in this scenario is a benefit.

No telephoto? Well then I probably would not bother – at least I would not bother trying to capture moon DETAIL.

Picking a Target

The moon is obviously one of our targets, but we want something interesting in the foreground to pair the moon with. Ideally we want a target that clearly stands above the surroundings and preferably one that allows us to get the proper distance away to maximize the “big moon phenomenon”. How far away?  Here is an easy formula: multiply the height of the object by 114.6.  If the object is 100 feet tall, the proper distance is 1,114.6 feet away.  If the object is 20 meters tall, the distance is 2,292 meters.  If 6 inches, then a distance of 687.6 inches is about right.

For the curious, the number 114.6 corresponds to 1 \div {\tan{(0.5)}}, where 0.5 is the number of degrees of the angular size of the moon from anywhere on earth. If shooting from somewhere else in space more advanced trigonometry may be needed.

It might be tempting to start with something short and nearby, like a golf ball. But getting a good depth of field is going to be difficult.

Let’s get started on the target, shall we? Fire up The Photographer’s Ephemeris (TPE) and follow along with me.  Switch to Ephemeris Mode (it is the first selection in the upper left). In the search bar (lower left), enter “Pioneer Park, San Francisco, CA“.

Now would be a good time to make the TPE window as large as possible, and select the “Satellite” mode in the map.

Figure 1: Pioneer Park Coordinates and Elevation according to TPE

Right above the upper right corner of the map you should notice two things: an elevation (here shown as +190 ft), and the GPS coordinates (37.8…blahblahblah).  If you prefer metric (or it shows metric and your prefer feet, you can change that using “Configure”).

Looking at the zoomed in map, put the cursor over the map near the bottom and click and drag upward. The map should move and soon you should see a conical shape casting a long shadow. Hooray. You found the Coit Tower. Double click in the center of the structure and it should look about like this.

Figure 2: Coit Tower in Pioneer Square, San Francisco, CA

Here I cheated and moved the elevation (+266 ft) and the GPS coordinates on to the image from above the map from the bar above.  I also zoomed out a bit so you can see the parking lot that you first landed on.

Did you notice that the elevation moved up from 190 to 266 feet?  You gained 76 feet in just a few parking spaces! It is steep there, but that number is NOT a measurement of the height of the tower, my friend. That is the elevation of the BASE of the tower. Don’t believe me… click a few spots near, but not on the tower or the building.  Click things farther away if you like, I’ll wait.  As you can see from the image at left taken from the parking lot, there is clearly not a gain of 76 feet between the two places.  The elevation information comes from a variety of sources, mostly the United States Geological Services (USGS) data.

What you hopefully learned is not to COMPLETELY trust the elevation shown. The elevation does not include buildings or trees and is not that precise, but it will probably be good enough.

In a while you will need to know the height of the tower above the base. Guess where you can find that? Yep, Google. Did you find it yet? It’s 210 feet (65.4 meters) tall.

So doing the math: ideally we’d like to be 210 x 114.6 feet away (24,066 feet or 4.5 miles) to have the moon’s apparent size be as big as the tower. Unfortunately going to the east, our choices are mostly in the San Francisco Bay, farther away on the Oakland Shore (near the Bay Bridge), or closer. Treasure Island looks like a good spot. It’s 2.11 miles and there is a lot of flat, publicly accessible shoreline to move along to align the moon behind the Coit Tower.  And besides even though the Coit Tower sits up on a high hill, only about the top half of the tower is above the sky line. So 2.11 miles might work out very nicely.

Since we have chosen a site to the east of the Coit Tower when can the moon appear behind it?  Near moon SET of course.

If you want your diagram to look exactly like mine, change the calendar to June 15, 2011. And change the Ephemeris mode to “Detail” (use the D key, or click the box down near the calendar).

When you switch to Detail mode, a hollow little gray marker will appear. Usually to the right of the red marker near the right edge of the map. Don’t lose it – you’ll need it in a minute.

Calculate the Moon Location Near Moon Set

You may have noticed all those colored lines extending from the Coit Tower in Figure 2. Here is what they mean: the light yellow line is the direction of sunrise, the orange line is the direction of sunset. The light blue line is the direction of moon rise and the dark blue is the direction of moon set.  All by itself that won’t help much. To see the moon setting in the west behind the Coit Tower, you obviously must stand to the EAST. But where?

Zoom out your map until you can see the Coit Tower on the left, and Treasure Island on the right. Make sure you are in Detail Ephemeris mode (you’ll know when you see a graph like this:

Figure 3: Sun/Moon graph and time slider.

Your map will look something like this:

Figure 4: SF Bay Map with Coit (lower left) and Treasure Island (upper right)

I have stripped off all the stuff around it to focus your attention. You’re focused, right?

Now would be a good time to play with the time slider. Click and drag it. Whoa! Did you see the lines moving? The skinny ones, that is.  There is a lot going on here, but the one thing you’re not yet seeing is where you need to stand to see the moon behind the Coit.

Stephen Trainor, the author of TPE put a cool feature in this tool. He did so because I asked politely and I support him with donations – I urge you to do so too. Buy his iPhone/iPad version of the tool (or Android if that’s available) or make a donation if you’re using the desktop (free) version of the Ephemeris. It’s the right thing to do!

Move your time slider to 5:13 as in Figure 3.  Now hold down the shift key. Did you see the thin blue line jump out? That blue line traces roughly where the shadow of the moon would appear. It can’t be completely accurate, however since the exact location would have to take into account topography, trees and man-made structures. We helped ourselves around that worry by choosing a flat shoreline where not much can get in our way.

Now would be a good time to find that hollow gray marker. Lost it? Click “D” then “D” again. It will appear near the right side of your map connected by a dim gray line to the red marker.

Hold down the shift key again, and drag and drop the gray marker on the Treasure Island shore DIRECTLY over the dark thin blue line.  Zoom in if you have to and get the marker EXACTLY on the line. And try not to stand behind a building or a palm tree.

You probably didn’t notice, but three things appeared at the bottom of your Ephemeris Graph in the box labeled Geodetics.  Those are: Apparent Altitude (which here will be negative), Change in Elevation (also negative), and Distance and Bearing.  Each time you move the gray or red marker it will recalculate the distance, altitudes and angle between gray and red.

One last little coup for now… notice next to the word Geodetics it has a little red and gray dot with an arrow over the top? Yeah, click that. The gray and red locations magically flip. Now all of your altitude and elevations will be positive. The calculations are FROM red TO gray. Since red is at sea level now, and gray up 266 feet on the top of Pioneer Hill the angle above the horizon toward the hill is  positive: specifically the base of the Coit tower is 1.1 degrees above the horizon. So can we conclude that the moon must be 1.1 degrees high in the sky?

NOPE. Sorry, we can’t. So close and yet SO far!

Q: What is wrong? Did you figure it out?
A: TPE has no idea how tall the Coit Tower is! (Stephen tells me one day he’s going to add the ability to specify the height at the red or the gray marker), but for now, YOU have to make that adjustment yourself. I’m afraid it’s going to involve some math. Trigonometry, actually.

What is the CORRECT Angle?

If you can answer this question, you’ll get the solution. “If an object at 2.12 miles away is 210 feet taller than the current 1.1 degree elevation, how many more degrees will that be?”

\tan^{-1}(Height / Distance) = altitude\ in\ degrees

Or in this case  InverseTangent( 210ft / 11311ft ) = 1.06 degrees.

So the CORRECT altitude is 1.06 + 1.1 or 2.16 degrees.

Hint Use the built in calculator in MS Windows in Scientific mode (Alt+2). Set the units to degrees. To get to the inverse tangent function (also called tan-1) use the “i” (inverse) key.

NOTE: If you do not want to do the trigonometry, there is another way to find the angle: use your camera.  Go to the desired site, take a picture with your telephoto lens aimed level with the horizon and with the top of the object visible. Determine the angular field of view of your lens/camera combination. Then measure the height of the target on the image and use the ratio of the height of the target to the field of view.  That sounds complicated, but it’s actually pretty easy. Using a 200mm lens, my angular field of view is 4.3 degrees. My photo shows that the tower spans 1000 of 1800 possible pixels. So the tower is 4.3^{\circ} \times (1000 / 1800) = 2.388^{\circ}

Now that we know the moon altitude must be 2.16 degrees we do not have to start over. Let us make sure the red maker is back on the tower and adjust our slider until the moon height is 2.16 degrees, then follow the line of the direction of the moon set to get our new location.

Of course if we move significantly higher, lower, nearer or farther away we must recheck the angle calculations.  In a hilly or mountainous location it is extremely non-trivial to get all the heights and angles just right. Using the “Terrain” mode of the map may help, but changes of a few dozen feet may make a big difference in the alignment.

Just remember the following things:

  1. The satellite maps may be out of date. A tree, building, crater, fence or obstacle might be in the location you want – or directly in front of it.
  2. There is no substitute for prechecking the line-of-sight BEFORE the event (see 1 above)
  3. Terrain maps are not visible when zoomed in.
  4. Elevations of the terrain are ROUGH.
  5. Moving 10 feet to the left or right may make or break the shot.
  6. I am NOT available to solve your trigonometry problems! Ok, I am but there will be a fee!

But wait, there’s more!

Getting the Ideal Exposure

To get the ideal scenario for moon details AND foreground light, it helps that the sun is on the opposite side of the sky and sometime during Civil twilight. In Figure 3, above, notice how the time we arrived at (5:13 AM) has the moon 2 minutes before Civil twilight.

Wondering what Civil twilight is? It is the legal equivalent to either dusk or dawn. Dusk when the sun has set, dawn when the sun has not yet risen. Signs that say park hours are “Dawn to Dusk” mean something quite precise. But those times change daily. For more click on the word “Civil” in the Ephemeris and it will tell you! Or take a look here.

The ideal exposure for detail in a full moon is about 1/100 of a second at ISO 100 and f/9. But atmospheric conditions, and the moon’s altitude may significantly affect the settings to use.  The best choice of aperture is to stop down enough for a sharp shot that keeps the foreground through to infinity (the moon’s focal distance) in focus.  If your foreground is at or beyond your hyperfocal distance (as it most probably will be), you’re good to go.

The problem, of course, is that your foreground is probably not going to fare well unless it is also well lit – so bracketing your exposures is always a great idea. The darker the twilight, the wider the bracketing needs to be.

Verifying The Sight Lines

After all the calculations and planning, a group of Bay Area Night Photographers ran out at the crack of before dawn to capture the “Full Moon Set behind Coit Tower“. One of the bleary-eyed ambitious photographers was Phil McGrew. Phil get’s extra kudos for going the morning before the planned event (that’s two thermoses worth of coffee) and here is what he got:

Photo 5: Coit Tower? And the Moon by Phil McGrew

The moon is in the right spot, but, whoops, there is something else in the shot, too! A big square building blocking the view behind the tower.  A more thorough scouring of the map in Figure 4 might have revealed the problem (see Figure 5).  Behind the Coit, and set up on a hill are a series of apartment buildings.  From almost anywhere else on Treasure Island, or Fort Baker in Marin, the Coit tower sits all by itself on the skyline.

Figure 5: Oops! (Click to see it larger)

What are the takeaways here:

  • There is no substitute for direct observation from the planned location. Any number of things can be a problem from light posts, billboards, trees and shrubs to, well hulking square buildings in the line of sight.
  • Extra scrutiny of the sight lines in TPE *might* save one from a needless trip to get a direct observation.
  • Knowing the local topography helps as does picking a structure or formation that clearly stands above the surrounding area.

Phil also discovered that the lack of brightness on his foreground meant he had to choose between exposing for moon detail, or exposing for the foreground. In Photo 5 he nailed a great foreground exposure and might be able to tease some moon detail out of the RAW file.  Or he could resort to…

One Last Trick – HDR

First I am a hater of images that have been composed by dropping a well exposed (oversized) moon into a separately taken landscape. There are technical challenges to embrace here so why not embrace them! Besides my desire as a scientist and engineer is to maintain reality through honest acquisition.

I am not, opposed, however, to using technology to overcome the limits of technology. Namely a camera can not readily capture the range of exposure – brightest to darkest – that the human eye can so a trick called “High Dynamic Range” photography (also called tone compression, tone mapping or image fusion) is sometime a necessity.

In the morning of June 15th, moonset behind Coit Tower was the target as describe earlier. That evening, moon rise behind the Transamerica Building was the goal.

You can click the diagram to the left to see where we were. As kismet would have it, the very parking space that I had calculated at the correct spot was open and I pulled in!

The haze was heavy, contrast was low. But in the end, the moon peeked (and peaked) right on schedule and right where it was supposed to go. It is always satisfying when things work out like that. More satisfying if the weather is great.

Rising Moon Collage

Photo 6: Moon rising over San Francisco (through the haze)

The fifth shot in the panel above is like all of the others in that it is a three-shot bracketed exposure combined using Photomatix Pro. The three shots were:

Figure 7: Bracketed Exposures

A wider bracketing range may have helped, the haze was quite thick. Using Photomatix Pro, playing with the knobs a bit I got this result:

Yellow Moon [5_032356-8tm]

Photo 7: High Dynamic Range Composite of 3 Images

I can only imagine what having a clear day to shoot in might have accomplished.

Best of luck on your alignments!

Comments, questions, praise, quibbles over the math – we’ll listen. Find us on Facebook.  Or attend one of our workshops. Want to keep it cheap, hook up with me, Steven in the Bay Area Night Photography group.

 

Alignment (Part 1 of 2)

Sometimes alignment is everything. As an amateur astronomer at heart I am fascinated by the course of celestial bodies through the heavens and how they coincide with terrestrial features (is that strange?). Buildings, lighthouses, arches, and yes, observatories all beg to be photographed as they are kissed by the moon, the sun, or the Milky Way.

One example is shown in Photo 1, below. The moon is rising behind the Lick Observatory. The observatory is perched on the top of Mount Hamilton overlooking San Jose, California.  The photo was taken from the shore of Halls Valley Lake in Joseph D. Grant Park County Park. But it was not serendipitous – it was purposeful.  Days and weeks worth of planning were required.

Moon Lick [5_009717]

Photo 1: The full moon rises over Lick Observatory, Mount Hamilton, San Jose, California

An alignment of man-made artifacts and the moon occurred on the night of a total lunar eclipse.  It also was not completely accidental – but I can not claim I knew I would capture it:

Airplane Transits the Partially Eclipsed Moon

Photo 2: An airplane transits the partially eclipsed moon.

But sometimes the moon just happens to be in the right spot, as in this photograph by May Wong which captured the moon in an interesting alignment while hiking up a trail in Mission Peak Preserve.

Photo 3: (May Wong) The moon teed up on Mt. Allison's Tower

Many fascinating views of the sun and moon can be found in books by Harold Davis one particularly interesting example is “100 Views of the Golden Gate Bridge“.

Planning Moonshots

Ignoring happy accidents for a moment, getting the moon to align with some terrestrial object involves quite a bit of calculation. While there are some great tools to aid the lunar photographer (The Photographer’s Ephemeris, for example), it helps to understand why the moon is a difficult object to catch.  Starting with the first problem:

The Moon is BRIGHT

Jewel [C_029690]

Photo 4: Long exposure for details during a total eclipse - notice the few stars.

Indeed the moon is a very bright object as most people discover when they try to capture any of the details of the moon. Typically the full moon requires settings of f/9, ISO 100, and 1/100 of a second to preserve detail; but at night, those  settings result in everything else being a deep black, therefore to get moon details and foreground details there must be some illumination.  The best time is before sunrise or after sunset and more specifically the very best time is on the cusp between nautical twilight and civil twilight.  I will explain what those are in Part 2.  Of course the moon also makes planning harder by the changing daily illumination. In 29.53 days the moon completes one full cycle from new where the moon is in line with the sun and not illuminated; to full – opposite the sun in the sky and fully illuminated; and back to new. Surprisingly, however, the exposure needed to capture moon detail does not change very much until the moon becomes a slender sliver. When in the sliver phase longer exposures can capture moon detail in the darker (unlit) portions of the moon though this effort comes at the cost of blowing out detail from the lit edge.  In the extreme case, as when eclipsed (Photo 4) longer exposures are needed.

This brings us to the second problem:

The Moon’s Path through the Sky Changes Daily

As if the changing illumination were not enough the moon’s path through the sky  dramatically changes from day to day. At my latitude (39 degrees north) the moon rises about 42 minutes later each day.  The compass direction (azimuth) at which the moon rises and sets also changes significantly from day to day.   Capturing the moon near the horizon during twilight ALWAYS means attempting a shot of either a slender crescent moon or a full moon.  In most months at most 2 days near the full moon provide full moon capture opportunities. What about the other phases? During the first quarter, the moon is highest in the sky near sunset. During its last quarter the moon is highest in the sky at sunrise. So in short, at first and last quarter you have to shoot nearly straight up to get the moon.

NOTE: First quarter refers not to the amount of the moon that is lit – it is half lit – but to the phase. Similarly at last quarter the moon is also half lit.

Determining the rise and set times of the moon is not hard. Many sites feature the sun and moon rise times.  www.sunrisesunset.com is one site I like. sunrisesunset.com can generate a calendar for a whole month. With a little experience it is often enough to know what phase the moon is in. For me a calendar that does not feature moon phases is useless!

Once I choose which direction I will be shooting, I then know whether I must shoot near sunrise or sunset. Pigeon Point Lighthouse – my nemesis – is on the west coast. To capture the moon behind it the full moon must be setting – which means the sun is rising.  (It also means a 3:00 AM wake up to allow me time to drive to the coast!) Conversely when  attempting to capture the moon over the San Francisco Bay Bridge, the best viewing locations face east – meaning an evening (sunset) shot is best. One advantage to attempting the full moon is that the sun’s glow illuminates the face of the foreground whereas when shooting a crescent the sun and moon are on the same side of the sky so the foreground is in silhouette.

Now we face problem three:

The Moon is Tiny

In this wide angle shot, it is difficult to even see the moon! It’s there in the upper left, but with the 10mm lens the entire moon occupies about 467 pixels out of the 15,154,290 (15M) total pixels. That’s a paltry 0.03 percent of all the pixels in the image. Of course the moon is not tiny, it is very large but it is so far away that its angular size is 1/2 of a degree or about the width of your pinky finger at arms length.

When the Lights Go Down in the City [5_018683]

Photo 5: 20mm Focal length = tiny Moon... did you spot it?

Often my goal is to include a moon in a way that shows it large and well featured relative to the foreground. There is no practical way to get closer to the moon, so the way to make the moon larger in the frame is to use a telephoto lens (as in photo 1 and 2).

Putting the moon near some foreground element allows me to exploit the large moon phenomenon as shown in Photo 1. But it is not enough to use a telephoto lens – I must also be far enough away from the object in question so that the apparent (angular) size of the moon is nearly equal to the angular size of the foreground object. The proper distance can be measured with the pinky fingernail at arms length, or calculated with some trigonometry. In Part 2 I’ll supply a simple formula that works well. Meanwhile Figure 1 illustrates the challenges involved in positioning and “sizing” the moon relative to a foreground object.

Figure 1: Relative sizes of the moon based on distance from the foreground object. See notes.

NOTE: To keep the lighthouse the same size as shown in images A, B, and C above the focal length must be increased. Alternatively, using one fixed focal length pictures B and C can be cropped from a larger photo.

And there is another complication, too, depth of field. The longer the focal length the harder it is to keep the foreground and the background in focus. And one last complication:

Near The Horizon, Atmospheric Conditions have a Significant (Negative) Effect

Looking straight up there are about 50 kilometers of atmosphere to diminish the quality of a photo. Looking toward the horizon, that number is effectively 38 times as much! The sky must be clear of clouds and haze through the entire distance. And a more sinister thing occurs, too. The atmosphere bends the light. When objects like the sun or moon approach the horizon the atmospheric distortion can become quite noticeable as a vertically flattened object. And finally, due to refraction when the sun or moon appears to be setting, it in fact has already fallen below the horizon and remains visible only because of  refraction.  The take away here is that trying to capture a detailed moon at the horizon is not as effective as capturing the moon at least a few degrees above the horizon.

In Summary

To capture the moon near a terrestrial feature:

  • The moon’s current illumination must be managed.
  • The moon’s rising (or setting location) must be accurately calculated.
  • Exposures to capture moon detail require the right amount of foreground illumination (near twilight)
  • The location chosen must have an unobstructed view of the sky toward the desired direction.
  • To get a “big moon” it is necessary to get far enough away from the foreground to get the relative moon size as desired. If too close, depth of field problems arise.
  • A well supported telephoto lens is required.
  • Capturing a shot of the moon near the horizon means the atmosphere must be relatively clear of clouds, dust and haze.
  • Too low in the sky means there will be significant distortion from the atmosphere.

So there it is: all the complications that must be overcome in order to capture the moon. I just have not written HOW to overcome all those obstacles, that information is coming in the next installment.