Starship Asterisk*

Posted: **Thu Mar 24, 2011 4:06 am**

Boston Moonrise

Explanation: Last week's Full Moon was hard to miss. Rising on March 19, its exact full phase occurred within an hour of perigee, the closest point in the Moon's orbit to Earth. As a result it appeared some 14 percent larger and 30 percent brighter than a Full Moon near apogee, the most distant point in the elliptical lunar orbit. Seen here, the near perigee Full Moon still hugs the horizon, distorted by atmospheric refraction as it rises over Boston, Massachusetts, USA. The telescopic night skyscape was shot from Prospect Hill in Waltham, Massachusetts, roughly 10 miles from the Boston skyline. Just to the left of the orange lunar disk is the distinctive control tower at Boston's Logan International Airport. Topped by lights, the tall, twin towers of the cable-stayed Zakim Bridge spanning the Charles River are also included in the scene. If you managed to miss this perigee Full Moon, make a note on your calendar. Your next chance to see the Moon this large and bright, this time at full phase within only a few minutes of lunar perigee, will be next year on May 6.

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Posted: **Thu Mar 24, 2011 4:44 am**

APOD Robot wrote: Your next chance to see the Moon this large and bright, this time at full phase within only a few minutes of lunar perigee, will be next year on May 6.

Yay! There were clouds this year for me, so I only saw it the
night before (still pretty close to perigee and noticeably larger).
Thanks for this calculator, too.

On a related note, what makes for the differences in perigee distances?
Next year's May 6 perigee full moon will be 376km further than this year's;
the variation in perigee distances for 2011 ranges from 356 577 to 369 565 km:
that's a difference of 12 988km!

Sam

Posted: **Thu Mar 24, 2011 12:53 pm**

The moon seems SO big. Was it taken at magnifacation after the skyline was shot? That makes it seem like a hoax.
Whit

Posted: **Thu Mar 24, 2011 1:11 pm**

I especially like the picture of the man measuring the moon, with-out a space-suit

Posted: **Thu Mar 24, 2011 2:28 pm**

Whit in Chillicothe, OH wrote:The moon seems SO big. Was it taken at magnifacation after the skyline was shot? That makes it seem like a hoax.

The problem is, many people don't understand that images are translating angular scale to linear scale.

The Moon is 0.5° degrees across. It has this angular size regardless of the lens used, or where on Earth you are standing. If you shoot it with two lenses, say 100mm and 200mm focal length, the longer one will map that angular size to twice the linear dimensions. That is, the Moon will appear twice as large on the image.

Cameras do the same exact thing with terrestrial objects, of course. But what is the angular size of a terrestrial object? Unlike the Moon, it isn't fixed, but depends on how far away you are from it. Take a picture of the Moon rising over your roof from the front yard, and your chimney might subtend about 0.5°, meaning the Moon and your chimney will look the same size in the image. Take the same image from a couple kilometers away, however, and now your entire house only subtends 0.5°. The Moon and your house now appear the same size!

Note that this has nothing at all to do with magnification, the type of camera or lens used, or anything other than simple geometry. All of these moonrise images are constructed the same way: you have the position of the observer, a Moon of (effectively) invariant angular size, and intermediate terrestrial objects with angular sized determined by their distances from the observer. The trick to making the Moon look huge in an image is simply to ensure that your foreground objects are far away.

Posted: **Thu Mar 24, 2011 2:54 pm**

I thoight this link was neat!

http://asterisk.apod.com/viewtopic.php?f=29&t=23185
I also liked todays APOD! Full moon rises are always neat.

Posted: **Thu Mar 24, 2011 3:06 pm**

Thanks for that information Chris. It makes sense.

Posted: **Thu Mar 24, 2011 10:11 pm**

http://www.nonsenselit.org/Lear/ns/pussy.html wrote:

The Owl and the Pussy-cat went to sea
In a beautiful pea green boat,
They took some honey, and plenty of money,
Wrapped up in a five pound note.
The Owl looked up to the stars above,
And sang to a small guitar,
'O lovely Pussy! O Pussy my love,
What a beautiful Pussy you are,
You are,
You are!
What a beautiful Pussy you are!'

Pussy said to the Owl, 'You elegant fowl!
How charmingly sweet you sing!
O let us be married! too long we have tarried:
But what shall we do for a ring?'
They sailed away, for a year and a day,
To the land where the Bong-tree grows
And there in a wood a Piggy-wig stood
With a ring at the end of his nose,
His nose,
His nose,
With a ring at the end of his nose.

'Dear pig, are you willing to sell for one shilling
Your ring?' Said the Piggy, 'I will.'
So they took it away, and were married next day
By the Turkey who lives on the hill.
They dined on mince, and slices of quince,
Which they ate with a runcible spoon;
And hand in hand, on the edge of the sand,
They danced by the light of the moon,
The moon,
The moon,
They danced by the light of the moon
.

Posted: **Thu Mar 24, 2011 10:27 pm**

: A heart-shaped crater in the Galilae region on the Moon. Credit: ASA/GSFC/Arizona State University; 3-D by Nathanial Burton-Bradford.

Posted: **Thu Mar 24, 2011 11:09 pm**

Whit in Chillicothe, OH wrote:The moon seems SO big. Was it taken at magnifacation after the skyline was shot? That makes it seem like a hoax.
Whit

Whit,

Chris has provided a thorough description of the trick behind such photos (as usual).

Here is my description from a recent post involving the various factors of interest when pursuing such photos: http://asterisk.apod.com/viewtopic.php? ... 10#p142510 (see bottom of the thread).

Anthony.

Posted: **Fri Mar 25, 2011 12:25 am**

Have you noticed that the "Rabbit" in the moon, looks like the Energizer Rabbit?

Posted: **Fri Mar 25, 2011 1:30 am**

Boomer12k wrote:
Have you noticed that the "Rabbit" in the moon, looks like the Energizer Rabbit?

: Energizer Bunny

: <<GigMasters helps you hire professional Easter Bunnies in the Boston area. Whether it's a wedding, corporate event, or private party, you'll easily find a qualified Easter Bunny in Boston and throughout Massachusetts.>>

Posted: **Fri Mar 25, 2011 2:03 am**

Beautiful and interesting photograph.
Chris's explanation is truthful, relevant and clear.
Greetings
César

Posted: **Fri Apr 01, 2011 6:10 pm**

March 19th's "Super Moon" Over Boston
Sky & Telescope | Dennis di Cicco | 2011 Apr 01

...
While I have the ability to calculate the precise location of the rising Sun and Moon from a give spot, the last-minute nature of this photo ruled out doing the math. I did know that the Moon would rise behind the “interesting” part of the skyline, but not exactly behind which features.

The full Moon rose along the distant horizon, its shape grossly distorted by atmospheric refraction. Just to the left of the orange lunar disk is the distinctive control tower at Boston's Logan International Airport. To its right, topped by lights, are the tall, twin towers of the cable-stayed Zakim-Bunker Hill Bridge that spans the Charles River near its mouth.

Well, despite the last-minute preparations, it all worked.
...

Starship Asterisk*

APOD: Boston Moonrise (2011 Mar 24)

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