Difference between revisions of "2463: Astrophotography"

Explain xkcd: It's 'cause you're dumb.
Jump to: navigation, search
(Explanation)
(Explanation)
Line 16: Line 16:
 
* There is a partial solar eclipse (the view of the sun is partially obscured by the moon on the upper right). The sun is much larger than the moon, but the moon is able to block a significant fraction of the sun's light from reaching Earth because it is much closer to the Earth. The same optical arrangement is popular in photography, where it is possible to show the silhouette of a person or a cityscape in front of a full moon, making the moon look comparatively larger or smaller by adjusting the distance to the closer subject, and then the lenses used by the photographer to make them both fill just the right amount of the frame.
 
* There is a partial solar eclipse (the view of the sun is partially obscured by the moon on the upper right). The sun is much larger than the moon, but the moon is able to block a significant fraction of the sun's light from reaching Earth because it is much closer to the Earth. The same optical arrangement is popular in photography, where it is possible to show the silhouette of a person or a cityscape in front of a full moon, making the moon look comparatively larger or smaller by adjusting the distance to the closer subject, and then the lenses used by the photographer to make them both fill just the right amount of the frame.
 
* A person slightly below the peak of a mountain is juggling, with several of the balls also in front of the sun.
 
* A person slightly below the peak of a mountain is juggling, with several of the balls also in front of the sun.
* An archer at the peak is firing arrows from a bow, and one arrow has pierced what at first appears to be one of the juggling balls, but is probably a Transit of Venus. §
+
* An archer at the peak is firing arrows from a bow, and one arrow has pierced what at first appears to be one of the juggling balls, but may be a Transit of Venus. A simultaneous Eclipse and Transit of Venus is actually expected in the future, but not until April 5, 15232.
 
* Two airplanes flying above them are pulling signs with the words "nice" and "shot" (which could refer to either the archer or the photograph).
 
* Two airplanes flying above them are pulling signs with the words "nice" and "shot" (which could refer to either the archer or the photograph).
* The ISS can be seen transiting on the upper left.
+
* The ISS can be seen transiting in the upper center.
  
Taking the picture required precisely scheduling and arranging the relative positions of several of the various subjects (and photographer), to coincide with the predictable but rare conjunctions of the rest of the scene.
+
Taking the picture required precisely scheduling and arranging the relative positions of several of the various subjects (and photographer), to coincide with the predictable but rare conjunctions of the rest of the scene, as well as special equipment:
 
+
* A solar filter must be used to photograph the sun without overexposing the image or even damaging equipment.
§ A simultaneous Eclipse and Transit of Venus is actually expected in the future, but not until April 5, 15232.  
+
* The photograph must be taken during a partial solar eclipse. These only happen a few times per year and are only visible in part of the world.
 +
* Related to the last point, a nearby person appears larger than the moon. It is possible to photograph the silhouette of a person or a cityscape in front of a full moon, making the moon look larger or smaller by adjusting the lenses used and the photographer's distance to the closer subject. The photographer needed to carefully choose their position relative to the sun to make this happen.
 +
* The eclipse occurred with the sun high overhead, so the photo had to be taken from below the subjects. The archer and juggler had to climb a mountain, with the photographer possibly several miles away at the base.
 +
* The exposure time of the photograph had to be short enough to capture clear silhouettes of the juggling balls and arrows while these were in the air.
 +
* The mountain had to be in a location that would happen to see the ISS passing in front of the sun at the same time.
 +
* The subjects had to achieve a moment in which five juggling balls were in the air and an arrow had pierced on the balls, while sideways relative to the sun's light, which was still near normal intensity and could have made the task harder. The planes also needed to be flying in the correct directions for the text of the signs to be visible.
  
 
==Transcript==
 
==Transcript==
Line 33: Line 38:
 
:[Caption beneath the panel]:
 
:[Caption beneath the panel]:
 
:Our astrophotography community's one-upmanship is getting out of hand.
 
:Our astrophotography community's one-upmanship is getting out of hand.
 +
 +
==Trivia==
 +
Randall has commented on in comics ([[1855:_Telephoto]], [[1719:_Superzoom]]) and the ''How To'' chapter "How to take a selfie".
  
 
{{comic discussion}}
 
{{comic discussion}}

Revision as of 23:58, 14 May 2021

Astrophotography
[One hill over, a competing astrophotographer does a backflip over a commercial airliner while throwing a tray of plastic space stations into the air, through which a falcon swoops to 'grab' the real one.]
Title text: [One hill over, a competing astrophotographer does a backflip over a commercial airliner while throwing a tray of plastic space stations into the air, through which a falcon swoops to 'grab' the real one.]

Explanation

Ambox notice.png This explanation may be incomplete or incorrect: Created by a BACKFLIPPING ASTROPHOTOGRAPHER. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.
If you can address this issue, please edit the page! Thanks.

Astrophotographers like to take photos of things transiting the Sun. Typical things include planes, the International Space Station, and the Moon.

The practice of "one-upmanship" refers to the practice of achieving something superior to what another has achieved, or "getting one up on" them. The caption claims that the photo shown in the comic is the result of a continuous string of one-upmanship among astrophotographers in a community, each striving to one-up the other.

In this comic there seems to be an abundance of things:

  • There is a partial solar eclipse (the view of the sun is partially obscured by the moon on the upper right). The sun is much larger than the moon, but the moon is able to block a significant fraction of the sun's light from reaching Earth because it is much closer to the Earth. The same optical arrangement is popular in photography, where it is possible to show the silhouette of a person or a cityscape in front of a full moon, making the moon look comparatively larger or smaller by adjusting the distance to the closer subject, and then the lenses used by the photographer to make them both fill just the right amount of the frame.
  • A person slightly below the peak of a mountain is juggling, with several of the balls also in front of the sun.
  • An archer at the peak is firing arrows from a bow, and one arrow has pierced what at first appears to be one of the juggling balls, but may be a Transit of Venus. A simultaneous Eclipse and Transit of Venus is actually expected in the future, but not until April 5, 15232.
  • Two airplanes flying above them are pulling signs with the words "nice" and "shot" (which could refer to either the archer or the photograph).
  • The ISS can be seen transiting in the upper center.

Taking the picture required precisely scheduling and arranging the relative positions of several of the various subjects (and photographer), to coincide with the predictable but rare conjunctions of the rest of the scene, as well as special equipment:

  • A solar filter must be used to photograph the sun without overexposing the image or even damaging equipment.
  • The photograph must be taken during a partial solar eclipse. These only happen a few times per year and are only visible in part of the world.
  • Related to the last point, a nearby person appears larger than the moon. It is possible to photograph the silhouette of a person or a cityscape in front of a full moon, making the moon look larger or smaller by adjusting the lenses used and the photographer's distance to the closer subject. The photographer needed to carefully choose their position relative to the sun to make this happen.
  • The eclipse occurred with the sun high overhead, so the photo had to be taken from below the subjects. The archer and juggler had to climb a mountain, with the photographer possibly several miles away at the base.
  • The exposure time of the photograph had to be short enough to capture clear silhouettes of the juggling balls and arrows while these were in the air.
  • The mountain had to be in a location that would happen to see the ISS passing in front of the sun at the same time.
  • The subjects had to achieve a moment in which five juggling balls were in the air and an arrow had pierced on the balls, while sideways relative to the sun's light, which was still near normal intensity and could have made the task harder. The planes also needed to be flying in the correct directions for the text of the signs to be visible.

Transcript

Ambox notice.png This transcript is incomplete. Please help editing it! Thanks.
[Cueball and Megan stand on a hill with the sun behind them. Cueball is at the top-left of the hill, holding a bow in his left arm, which has been recently shot, with the arrow to right. Megan is at the bottom-right of the hill, juggling some balls. There are two planes going in opposite directions with banners on them. Above the planes is the ISS. All these items are silhouetted against the sun partially eclipsed by the moon in the upper right.]
[Banners]: Nice Shot
[Caption beneath the panel]:
Our astrophotography community's one-upmanship is getting out of hand.

Trivia

Randall has commented on in comics (1855:_Telephoto, 1719:_Superzoom) and the How To chapter "How to take a selfie".


comment.png add a comment! ⋅ comment.png add a topic (use sparingly)! ⋅ Icons-mini-action refresh blue.gif refresh comments!

Discussion

So are any of those "balls" actually sunspots or the transit of Venus or something? 173.245.54.227 22:47, 14 May 2021 (UTC)

This looks like Destin from Smarter Every Day's lunar eclipse shot https://youtu.be/Nk0MRxXqo9s?t=610 108.162.219.78 23:20, 14 May 2021 (UTC)Yeedle

Destin also caught the ISS transiting during a previous eclipse: https://youtu.be/lepQoU4oek4?t=230 Astroboy (talk) 02:11, 15 May 2021 (UTC)
Yes and that was probably the one that needed to on up so I have added this to the explanation, before I read this coment. The other video has not much to do with transit. But that was also really cool, and I had not seen that one so thx. --Kynde (talk) 06:42, 15 May 2021 (UTC)
I now disagree with my self. Of course it is the combination of those two videos that are the backbone of the comic, with the other things put on top. Have added the second video to the ecplanation --Kynde (talk) 11:00, 17 May 2021 (UTC)

This is actually really cool. ISaveXKCDpapers (talk) 02:26, 15 May 2021 (UTC)

It might have been better with two planes that didn't look like they were dangerously within normal flight separation distances. Given they're not obviously 1000ft (300m) vertically apart (and very likely in Opposite Conflict, heading-wise) horizontal separation depthwise to the image should make the two similar models towing (similarly-sized?) banners noticeably off-scale to each other, even with the extreme foreshortening from the much distant cameraman. (Maybe the viewing angle 'up the mountain' would provide sufficient composite diagonal separation to comply with Reduced Flight Levels for two planes obeying hemispherical RVSM, but still with notable off-scaling.) They could be a stunt-pair, of course, asked for and given ATC dispensation (further complicated by the banner-towing) to cross absurdly close (by normal, sane standards) as per a fast-jet criss-cross at an airshow. It might have been even more impressive if one had been a notably 'bigger' class of plane (but silouetted at the same or smaller size) towing a similarly (give or take) rescaled banner. 162.158.158.131 02:43, 15 May 2021 (UTC)

That 1000ft separation rule only really applies to IFR flights at altitude. Under VFR (or, say, on approach where the aircraft can see each other) they can fly as close as is safe... whatever that might be. VFR flights can be scary close sometimes when crossing (especially when weaving through the corridors near to suburban airfields). I don't think the photo poses a particular problem in that respect. 141.101.98.38 09:03, 21 May 2021 (UTC)

I am really looking forward to seeing the simultaneous Eclipse and Transit of Venus 108.162.249.18 03:46, 15 May 2021 (UTC)

I look forward to reading Comic #2070397(ish?), and seeing if Randall revisits this! 162.158.159.122 13:19, 15 May 2021 (UTC)

The comic appears to say "one-upsmanship" rather than "one-upmanship". 141.101.98.46 17:16, 15 May 2021 (UTC)

One "one-upmanship" begets further multiple "one-upsmanship". (c.f. "Courts Martial", etc.) Or should they actually be "ones-upmanship"? ;) 141.101.98.30 17:56, 15 May 2021 (UTC)

"Sometimes it is specified as a hobby" "photographing the Sun is a popular subgenre within the field" seems like a perfect example of xkcd.com/1095 108.162.216.248 18:01, 15 May 2021 (UTC)

We are impressed with your creativity and determination and have a major international political issue we would like your guidance around. 108.162.219.204 19:33, 15 May 2021 (UTC)

i vote on changing it all to "ones-upsmansships" a la comic 1167. 172.70.34.162 13:04, 16 May 2021 (UTC)

Destin's video is in the second paragraph of the explanation of this comic For something that's not directly related to the content of the comic, that's quite a place of prominence. I don't think it should be there. At best, it should be moved to the trivia section as an example of astrophotography, not presented as fundamental to understanding this comic. Argis13 (talk) 19:44, 16 May 2021 (UTC)

As the whole comic is based on a combination of his two videos (also added the second) I think they deserve a very prominent place. It is obvious that Randall saw those two and made this tribute. --Kynde (talk) 11:00, 17 May 2021 (UTC)

Now that the comic points out the transit of Venus won't occur during an eclipse for thousands of years, it dawns on me the easiest way of achieving the apparent arrow puncture in the trick photo would be to put the ball on the arrow before shooting it. 172.69.62.9 05:03, 17 May 2021 (UTC)

Done --Kynde (talk) 11:11, 17 May 2021 (UTC)