Tag Archives: trigonometry

Geometry and The Moon

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Please do not run away. We are about to use adult language here. For example we will be using the word trigonometry. Still here? Good.  Here is a very pedestrian looking lunar eclipse photo taken with a 280mm lens*, cropped.

Near and Distant Neighbors

Very Ordinary Photo of the Lunar Eclipse with the planet Uranus in the lower left.

This past lunar eclipse several of us put our heads together to try to come up with a more creative photo than the one above. We had a trigonometry problem, however. On the West Coast the last moment of totality occurred at 4:24 AM PDT. We were brave enough to be out at any time of night – even if it meant extreme sleepiness in our day jobs but our problem was that the lowest the moon would be in the sky at the last bit of totality was 32.6 degrees above the horizon. We determined that angle using Stellarium, by the way. Unfortunately there is pretty much nowhere to go to get a nice large moon near an interesting object when the moon is almost 33 degrees high.

Wait: Why do we want the moon and the object to be similarly sized? Here is why… we want the moon to be noticeable like the Fantasy version below, not merely “present” like the real photo on the right. Even bigger would be better, right!?

N_281-608714+C_281-8150

Notice above right (Reality) and below how tiny the moon is compared to the building in the foreground?  Indeed, if you see a photo taken from anywhere on the West Coast where the eclipsed moon is significantly lower in the sky or larger than shown against foreground, you know it has been “photoshopped“.

Plan C: San Jose City Hall Eclipse Sequence

In short, it is nigh impossible to get the large moon effect with an altitude (angle) of 32 degrees here is why:

Calculating the Angles

Calculating the Angles

Just how far away do we need to be in order to get the moon the same size as an object of interest:

114.6 x object size

In other words, an object that is one foot tall, requires us to stand 114.6 feet away to make the 1/2 a degree angular size of the moon the same angular size as that 1 foot tall object.  The number “114.6” is from this calculation:

1 / TAN (0.5 degrees)

Yeah, that is trigonometry. Using still more trigonometry it is possible to calculate how high above the horizon a 9 inch tall object has to be so that it is “moon sized”.  We did that for you in the “Calculating the Angles” diagram above. Once you calculate the distance from the camera of 85.9, you can multiply that by the sine of the angle to calculate a height of about 46 feet! Here is the trigonometry:

Height = 85.9′ * SIN (32 deg)

You can go one step farther and calculate the distance from the object with ‘distance = 85.9 * COS(32 deg)’.

Of course after all that calculating you will still need to find a location, have contingency plans for weather and so on. At StarCircleAcademy we have built some tools and put together materials to help in all these endeavors.  We teach these things in our NP111 Catching the Moon Webinar.

The Road To The Temple

Below is where we ended up. This image is from our friend and co-conspirator Andy Morris.

Lunar Eclipse over Temple by Andy Morris of PhotoshopScaresMe

Four of us plotted and schemed to get an interesting shot. Above is Andy Morris’ result.  Click the image and you can read a great article about how he created the shot using Photoshop Skills at his site: PhotoshopScaresMe.com. In fact, it’s a great article which we strongly encourage you to read. You’ll learn how he composited the images together in Photoshop as layers.

The Long Conversation to Pick a Location

Andy has more details including how alcohol played a part in the process. Mostly I, Steven, was the wet blanket explaining why the geometry was all wrong.

  • The Stanford (Hoover) Tower looks like it is shrouded in trees from the needed angle
  • Bank of Italy (formerly BofA) in SJC doesn’t work
  • The main problem with the wind turbines is that the angle to the top of them is something around 12 degrees above the horizon which is 40 moon diameters below the eclipse.
  • Here is why the GG Bridge doesn’t work…
  • This seems to be the best solution I could find: the Coit Tower…
  • Darn. It would appear the coast is out. Forecast calls for Fog from SF to HMB
  • This might make an interesting foreground (see below)… Somebody want to check if they will mind us being on their property in the wee hours?

*Ok, we lied, it was actually a 70-200mm lens with a 1.4 TC on a full frame camera, but the net is the same: 280 effective mm focal length.

Where did you go and what did you get in your planning efforts?  Post a comment and link below… we’d love to see what you came up with!

Catching the Moon Simplified

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Freedom Gazes at the Moon [5_055475-7deB]

Freedom – the statue at the summit of the Nation’s Capitol – Gazes at the rising Moon

One of our popular webinars is Night Photography 111: “Catching the Moon (and the sun)”. The next webinar is April 2, 2014, by the way. Long before the many tools that now exist to help solve for moon+landmark alignments I began working on a tool I call the MoonChase Tool. As snazzy tools came into being like Stephen Trainor’s Photographer’s Ephemeris, SunMoonCalc, MoonSeeker, and many more, I neglected the MoonChase Tool and focused more attention on the Advanced Stacker PLUS. In fact, after Google discontinued the V2 map interface upon which MoonChase was built the tool languished for about a year and a half. I also stopped teaching how to use it in the NP111 Webinars. But, I kept finding that all existing tools just didn’t do what I needed, so I resurrected the MoonChase tool. I ported it to the newest Google Maps API (V3), and I then added some of the features I had on my wish list.  I’m really proud of what the tool can do now. And I have some fiendishly clever plans for the future of the tool, time permitting, of course. Operationally the MoonChase Tool is simple. The hardest part is coming up with the location where you want to stand and the landmark you want to face. If you know that there is a sightline to a landmark in the distance you can fire up MoonChaseTool and in 3 steps know when to go to get the moon or sun behind your landmark!  That’s right. You paste, paste, click and click. Or drag, drag and click. We cover how to cook up good locations in the Webinar. How do you get your hands on this tool? We’ll tell you! If you’ve attended a NP111 webinar with us, or purchased the video and notes you already HAVE access through the “private page” (you did save the password, right?).  You’ll find the link to the MoonChase Tool on the private page.  Or sign up for our webinar which includes the notes and video AND access to the MoonChase Tool – and you don’t have to wait for the webinar, we send you all the links when you sign up (see below). The tool isn’t especially pretty, we admit that.  But it is pretty EASY to use and it works even from your iPad or tablet as long as you have internet access.

3 Steps to Moon (or sun) catching

3 Steps to Moon (or sun) catching. And there is more: you can check the view with Google Street View, and even check the weather with the weather button.

After clicking “Moon” you get the report thanks to Jeff Conrad’s SunMoonCalc tool. Be careful to be sure it selects the time correctly. Below it’s off by an hour due to Daylight savings time.

LickFromSJC

Moonrise over Lick Observatory from near SJC Airport… all opportunities from this location for the next 4 years!

 

What Problems Does the MoonChase Tool Solve?

The tool was designed to do the trigonometry for you. Did you know there is trigonometry involved?  Don’t worry, you don’t have to know trigonometry or math.  Nor do you have to know about spherical coordinates, azimuths, altitudes or the three different kinds of twilight.  All you have to know is where you want to stand, and what you want to be in your picture. Drag the markers around on the map and click one of the Solve buttons. OR use the tool in concert with The Photographer’s Ephemeris.

What Do I Need to Know to Do?

It’s very helpful to be able to do the following things: grab GPS coordinates from Google Maps and/or Photographers Ephemeris.  We teach how to grab GPS coordinates in the course. You’ll also want to know how to find heights of your favorite landmarks. Google comes in really handy for finding heights of buildings!  One more thing you’ll want to verify is whether you can See the landmark from the place you want to stand. Again, we describe 4 different ways you can do that in the webinar. The rest is dragging and clicking!

How Long Will it Take?

If you already have the coordinates, it will take perhaps thirty seconds – or not even that long.

I WANT THAT! How Do I Get It?

Easy: Sign up for the webinar and you’ll get immediate access to the private page plus the videos and notes. If you’ve already taken the webinar, go to the private page and you’ll find the link in the Resources section.  Or as a prior purchaser, just sit tight as we’ll be sending the new materials out to all prior purchasers over the next 3 weeks.

Webinar: NP111 Catching the Moon and the Sun
Webinar: NP111 Catching the Moon and the Sun
Not Scheduled but usually 7:00 PM PDT (7 MDT / 8 CDT / 9 EDT) for 2 hours
Captured [C_044450-2tc] In this 110 minute Webinar, you will be introduced to several free (and almost free) tools that you can use to plan a moon (or sun) shot - including a tool written by Steven and made available only to attendees. Have you wanted to capture the moon "right where you want it" but weren't sure how? If you know you could resort to photo editing and fake it but you'd rather get the real deal then this class is for you. Steven will demonstrate how to determine when and where to go to capture an image like the Moon over Lick Observatory or the moon at the Transamerica Building or the sun shining through a portal in the Pacific Ocean (below). This is a Webinar so you can conveniently attend from your computer at work or home anywhere in the world. This course includes notes, access to a private page with details - including landmark events Steven has already solved for you, an online viewable recorded webinar with unlimited online viewing that you can watch NOW before the webinar is held. One indispensable tool covered in detail is the Photographer's Ephemeris by Stephen Trainor.

What You'll Learn

Steven will show
  1. How to Plan a moon or solar "contact" shot.
  2. How smartphone based tools may help - or sabotage - your attempts to get an alignment
  3. How to use the moon to illuminate your foreground,
  4. How the presence of the moon affects photos of the night sky,
  5. How to find information about interesting celestial events,
  6. How to find compelling locations for "alignment" images, and
  7. What camera settings you need to get it all exposed just right.
Photon Worshippers **Winner Astronomy Photographer of the Year, 2010 - People and Space **
Remember that this event INCLUDEs online videos, notes, and access to a special tool that Steven uses to solve lunar and solar contact shots.
Price: $41.25
New Dome [5_009671]

The moon rises behind Lick Observatory on Mount Hamilton, San Jose, California