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I was surprised that the moon only measures two degrees across the sky!

ncmncm 5y ago
Half the width of your thumb held out at arm's length. Sun, likewise, of course. So these radio lobes reach out another moon-width from both sides of your thumb.
shagie 5y ago
As noted, 0.5° across... but this misconception is in part because 360° or even 180° is really big when you're sitting at the center of it. I believe part of this misconception comes from that when we look at something, we're only paying attain to +/- 15° while the bifocal range is 120° and the full field of view with both eyes is about 200°. Additionally, the field of view of the photographs that involve the sun or moon are often in the 5° to 15° range. That narrow range photograph - https://www.deviantart.com/shagie/art/Crescent-Moonset-7082381 https://www.deviantart.com/shagie/art/Crescent-Moonset-70823... and that has a 3.4° field of view on the short axis. This is closer to the regular field of view - https://www.deviantart.com/shagie/art/Moon-and-sunset-3181113 https://www.deviantart.com/shagie/art/Moon-and-sunset-318111... though I shot it portrait rather than landscape. That has a 27° field of view on the short axis and a 40° field of view on the long axis. Another aspect of the moon and its size and the sky sphere - it moves at a fairly good clip. The sun is easier to think of though, it moves through 360° is 24h. That gives 15°/h or 0.25°/m. Every two minutes, the sun moves a solar diameter across the sky the moon has a similar amount of motion over a short period of time. This makes it difficult to take long exposures of the moon without a tracking mount.
- sliken 5y ago
  Heh, it's easy to think these days that the moon is larger than you think. Especially with so many articles showing huge detailed pictures of the moon. Try taking a picture of the moon with a cell phone (even one with the best in the market camera) and be prepared to be disappointed.
  - shagie 5y ago
    My first experience with "well, that didn't work" was about 30 years ago. I had a 35mm point and shoot (fixed focus too) camera. I shot one roll at night trying to photograph the full moon. They didn't even cut the film. When looking at the negatives, all that you could see on a long strip of film was an occasional very small black dot. From this, I learned two things: (1) The moon is much smaller in the sky than you think it is. (2) Take a picture of a white wall or similar thing to expose an entire frame so that additional frames can be calculated form that first (or last or both) frame and the proper cuts of the film can be made.
    - sliken 5y ago
      I've got a Pixel 6 pro, 4x optical zoom, decent sensor, and a astrophotography mode. It does take some nice sky photos, but the moon is just too small.
      - shagie 5y ago
        Cameras on phones just aren't designed for the narrow field of view that much of astrophotography uses. The thing to look up is "wide field astrophotography" - but even then, you get into issues. While it's a little dated (digital has come a long way), if you are interested in it with a "real" camera... hunt up a copy of Heavenly Bodies: The Photographer's Guide to Astrophotography by Bert P Krages.
      - wglb 5y ago
        My canon SX 50 does nicely, filling the viewfinder with the full moon

Half the width of your thumb held out at arm's length. Sun, likewise, of course. So these radio lobes reach out another moon-width from both sides of your thumb.

shagie 5y ago

As noted, 0.5° across... but this misconception is in part because 360° or even 180° is really big when you're sitting at the center of it. I believe part of this misconception comes from that when we look at something, we're only paying attain to +/- 15° while the bifocal range is 120° and the full field of view with both eyes is about 200°. Additionally, the field of view of the photographs that involve the sun or moon are often in the 5° to 15° range. That narrow range photograph - https://www.deviantart.com/shagie/art/Crescent-Moonset-7082381 https://www.deviantart.com/shagie/art/Crescent-Moonset-70823... and that has a 3.4° field of view on the short axis. This is closer to the regular field of view - https://www.deviantart.com/shagie/art/Moon-and-sunset-3181113 https://www.deviantart.com/shagie/art/Moon-and-sunset-318111... though I shot it portrait rather than landscape. That has a 27° field of view on the short axis and a 40° field of view on the long axis. Another aspect of the moon and its size and the sky sphere - it moves at a fairly good clip. The sun is easier to think of though, it moves through 360° is 24h. That gives 15°/h or 0.25°/m. Every two minutes, the sun moves a solar diameter across the sky the moon has a similar amount of motion over a short period of time. This makes it difficult to take long exposures of the moon without a tracking mount.

sliken 5y ago
Heh, it's easy to think these days that the moon is larger than you think. Especially with so many articles showing huge detailed pictures of the moon. Try taking a picture of the moon with a cell phone (even one with the best in the market camera) and be prepared to be disappointed.
- shagie 5y ago
  My first experience with "well, that didn't work" was about 30 years ago. I had a 35mm point and shoot (fixed focus too) camera. I shot one roll at night trying to photograph the full moon. They didn't even cut the film. When looking at the negatives, all that you could see on a long strip of film was an occasional very small black dot. From this, I learned two things: (1) The moon is much smaller in the sky than you think it is. (2) Take a picture of a white wall or similar thing to expose an entire frame so that additional frames can be calculated form that first (or last or both) frame and the proper cuts of the film can be made.
  - sliken 5y ago
    I've got a Pixel 6 pro, 4x optical zoom, decent sensor, and a astrophotography mode. It does take some nice sky photos, but the moon is just too small.
    - shagie 5y ago
      Cameras on phones just aren't designed for the narrow field of view that much of astrophotography uses. The thing to look up is "wide field astrophotography" - but even then, you get into issues. While it's a little dated (digital has come a long way), if you are interested in it with a "real" camera... hunt up a copy of Heavenly Bodies: The Photographer's Guide to Astrophotography by Bert P Krages.
    - wglb 5y ago
      My canon SX 50 does nicely, filling the viewfinder with the full moon