Planning a Lunar Eclipse shot with TPE for Android

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Total lunar eclipse

Regarding the upcoming lunar eclipse on April 14/15 2014, over on Google+ reader Stephen Schwam asks:

[H]ow can I figure out exactly where I should place myself to photograph this event ?? I have the hand held unit , gives [m]e a trajectory of moon rise. I am in Oregon and wanted to go to Smith Rock state park, capture a good foreground and also the phases of the eclipse, thanks.

Let’s run through the process using TPE on Android v1.2. But first, we need the detailed times for the eclipse, which we can get from NASA’s page :

EventTime (UT)
Penumbral Eclipse Begins:04:53:37 UT
Partial Eclipse Begins:05:58:19 UT
Total Eclipse Begins:07:06:47 UT
Greatest Eclipse:07:45:40 UT
Total Eclipse Ends:08:24:35 UT
Partial Eclipse Ends:09:33:04 UT
Penumbral Eclipse Ends::10:37:37 UT

We need to translate these times into our local time zone. For Smith Rock State Park, Oregon, on April 15, the local time zone is Pacific Daylight Time, which is 7 hours before Universal Time (UT, or UTC). For the purposes of this exercise we’re going to ignore the penumbral and partial eclipse phases (although you will want to capture those too if you want to create a sequence of photos showing the changes in the moon’s appearance through the event). The total eclipse starts at 7:06:47 UT minus 7 hours = 00:06:47 PDT and ends at 08:24:35 UT minus 7 hours = 01:24:35 PDT. It’s going to be a late night…

The first step in TPE is to find the correct location and set the date:

  • Tap “Search” on the Action Bar, and then type “Smith Rock State Park” – the red pin will move to the requested location
  • Optionally, tap “Add” to save this location for future use
  • Tap “Set Date” and choose April 15 2014

Screenshot

A few things to note:

  • This is the date of full moon, which of course is the only time a total lunar eclipses can occur
  • Other than the light of the moon, the sky will be totally dark (the sun having set several hours earlier)

Our next task is to establish the direction and height of the moon. To do that, we follow these steps:

  • Slide two pages across to the Azimuth/Altitude Details page
  • Adjust the time slider to 00:06 – the beginning of the lunar eclipse
  • You can toggle the slider from 24 hour mode to 1 hour mode for fine grained time adjustments
  • Note the direction (azimuth) and height (altitude) of the moon

Screenshot

We now know a couple of important facts about the eclipse: it starts when the sky is completely dark (long after the end of astronomical twilight), and the moon is already high in sky (+33.4° as shown in the screenshot above). That means that we may be limited in the types of shots we can obtain. Some potential candidate photo opportunities might include:

  • Telephoto zoom of just the moon
  • Juxtapose the moon against some silhouetted object
  • Moon plus light-painted landscape foreground
  • Moon reflected in the river

If the water is slow running and gives a good reflection, the reflection shot is one we could investigate further. (Looking at some of the photos of this location over on ShotHotSpot.com, it looks like there is some reflection potential.) With the moon high in the sky this shot might be a possibility.

I’ve never seen a photo of a totally eclipsed moon reflected in water: that’s either because the shot is impossible (too dark, maybe?) or it’s never been done. If it turns out to be a no go, we should at least have a clear view of the moon from this spot for a telephoto shot of the just the moon.

Screenshot

What about juxtaposing the moon against some of the rocks in the park? That would potentially give an area of black, with the stars and moon above.

  • Switch to Hybrid maps so we can zoom in closer
  • Advance the time slider to 00:45, the moment of greatest eclipse
  • Move the red pin to the River Trail on the west side of the ‘gooseneck’, to the north of Asterisk Pass
  • Zoom in to get an idea of the terrain

Screenshot

It looks like there is potential to get a shot of eclipsed moon above the rocks. If the rock profile is visually appealing, this could provide a nice silhouette opportunity (although the overall light levels will be very low, so exposure control will need to be finely judged). Alternatively, the rocks are probably close enough that they could light-painted with a suitable torch/flashlight, to provide a foreground subject for the red moon. But one critical question is whether the moon is visible from this location, or is it obscured by the rocks?

We can test these ideas out using the Geodetics functions in TPE:

  • Swipe once to the left to view the Geodetics page below the map
  • The secondary map pin (grey) appears to the east of the map centre
  • Drag and drop the grey pin on the rocks at the top of “Asterisk Pass” (labelled on the map, if you’re in Hybrid map mode)

Screenshot

By comparing the angle from red pin to grey pin with the altitude of the moon, we can check whether the moon is visible over the rocks at this time. With the moon at +34.7° and the angle to the rocks only +16.0°, it appears there’s plenty of room to play with. Additionally, you can see that the distance from shooting location to the top of the rocks is 297 feet, which is probably fine for longer exposure light painting with a suitable light source. You could capture separate exposures, one for the light-painting and another for the eclipsed moon and combine them in post-production if desired.

However, before we lock in our plans, it’s always worth spot checking a few other points nearby to ensure that you don’t miss any other areas that would potentially obscure the sightline. When we move the grey pin slightly to the south, it becomes apparent that the high point of our sightline actually will obscure the moon from this precise shooting location:

Screenshot

In some ways, this is good news. The small difference between the angle to the high point and the altitude of the moon (only ~1.5°, or roughly 3 moon diameters) means that we can probably find a shooting position quite easily by moving around on location to where the moon isn’t obscured. And when we do find it, the moon will be close to the top of the rocks, meaning that we can zoom in tight with a telephoto lens, thus ensuring the moon is a good size in our finished photograph.

Hopefully this post has given you some ideas of how to use the tools built into TPE to plan your lunar eclipse shots. Happy shooting!