3219: Planets and Bright Stars

Planets and Bright Stars

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Title text: An old astronomer trick for distinguishing the Sun from other stars is to take multiple photos a few minutes apart and overlay them, making the Sun stand out due to its high proper motion.

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Explanation

This is one of 75 incomplete explanations: This page was created by a GLOWING SPACE DOT. Don't remove this notice too soon. If you can fix this issue, edit the page!

This comic features a chart of a handful of cosmic objects and what they look like in the night sky. The joke is that they are all nearly identical dots, making the chart almost useless.

The comic shows an identification chart for some of the planets and bright stars visible at night from Earth. Bright shiny objects are often confused by people without astronomical experience, and the chart is supposed to make this easier by placing them adjacent to one another to easily see the differences. The joke is that the pictures look almost identical to one another, and therefore the chart isn't helpful at all.

The real way of distinguishing these objects is by their location in the sky. Stars can be found by using constellations, which are an apparent pattern of bright stars that make different regions of the sky distinguishable from one another. The planets can be distinguished by not belonging to the constellations, and further differentiated by their color, brightness, and movement relative to the stars (on the scale of weeks or months).

Selected objects do indeed look similar to one another in reality, but not identical. Some of them (in particular, the star Betelgeuse and the planet Mars) have a distinct reddish color, which can be seen in good conditions. The brightness is also different, and it can serve as a guide, but it's difficult to precisely judge brightness by eye, and the planets don't have a constant brightness over time. The differences are actually visible in the comic to a degree - e.g., the spots for Venus and Jupiter are slightly larger than the others - but they're subtle enough to not recognize at the first glance.

Each 'object' also has a colour, albeit extremely desaturated (very nearly white). If deliberately exagerated, the comic's planets and suns are all notably non-white.

• Planets:
  • Venus: the yellowy-orange hue of its cloud layers.
  • Mars: the red of its surface (given more muted saturation, in the comic, for the joke to work?).
  • Jupiter: the general orange hue of its combined cloud layers.
  • Saturn: a more 'peachy' orange of its clouds (no obvious hint of its ring system).
  • Mercury:: a yellow surface (not typically noted, in true-hue images, perhaps artistic licence from its proximity to the Sun).
• Stars
  • Sirius (binary system, primarily a main sequence A-type star): light blue.
  • Procyon (subgiant F-type star): more light green, or yellowy-blue/cyan.
  • Antares (M-type star, red supergiant): orange.
  • Altair (A-type, main sequence): light blue.
  • Betelgeuse (M-type, red supergiant): relatively dark red (usually visible as such in real eyes-only observations).
  • Vega (A-type, main sequence): light blue.
  • Polaris (ternary star-system, dominant member being an F-type yellow supergiant): extremely unsaturated cyan.

Using even a small telescope would make it easy to distinguish the planets by their brightness, size, and surface features. Additionally, using a spectroscope would allow for a measurement of the star's spectrum, which coupled with its brightness would allow an astronomer to easily distinguish between mentioned stars.

The title text suggests a "trick" for recognizing the Sun among other stars, suggesting measuring its proper motion (a measure of the angular component of a star's motion, in radians per second, perpendicular to the radial velocity vector) by overlaying several images. This does indeed differentiate it from other stars, but there are much easier methods, such as its extreme brightness and large angular size.^{[citation needed]} It is also completely unnecessary, except during a solar eclipse, because stars are not usually visible during the day, when the Sun is out. Additionally, "proper motion" is a term usually not used for the Sun.

Transcript

This is one of 46 incomplete transcripts: Don't remove this notice too soon. If you can fix this issue, edit the page!

[Caption: Planets and bright stars identification chart:]

[A 4x3 grid of planets and stars are displayed on a black background. White text below dots of light caption which object it is. Planets and stars are represented by almost-identical slightly fuzzy dots of white light.]

Venus

Mars

Jupiter

Saturn

Mercury

Sirius

Procyon

Antares

Altair

Betelgeuse

Vega

Polaris

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Discussion

There are sight color differences...209.240.116.218 19:55, 13 March 2026 (UTC)

I've created a version that brings out the color contrast, but I don't have permissions to upload it yet. How may I get those? Rumbling7145 (talk) 20:04, 13 March 2026 (UTC)

See Special:ListGroupRights for info about becoming autoconfirmed. In the meantime, you can upload the image onto an image hosting website such as Imgur or ImgBB and I can help you upload it! tori :3^{talk to me!} 20:20, 13 March 2026 (UTC)

[Ninjaed... You got there just before me, just realised I ended up Edit Conflicted...  :P Editing down to the bits that weren't said above.]

[...] you've been here a while, but 'only' edited thirteen times, it looks like [...]

[...and when someone else uploads it...] you can alwas add your own [claims to ownership], to the finished 'file page' [if the user concerned doesn't credit you already]. 81.179.199.253 20:31, 13 March 2026 (UTC)

Anyone know where that </div> overlaying "Add Comment" at the bottom of the discussion is coming from? Barmar (talk) 21:01, 13 March 2026 (UTC)

Well, Tori's signature is a bit lopsided with its tags, by the time it gets to the browser (is one </span> short, and has one closing </a> before the closing </span> that should have been within it), but not sure how that might have tricked-out the rest so that some closing </div> is redundant, without going through the entire page source to track down any other accumulated discrepancies.

I've seen that rogue close-div before, and I seem to recall that some precautionary extra close-tags (in either HTML or Wiki markup) have been added to 'make sure' some things don't run on. But it seems to vanish after some later edits (either main comic page or discussion one), and I would have imagined that the excess tag would just be 'ignored' under most circumstances. But it's difficult to tell easil tell what a combination of meta-tagging and actual tagging does.

And there's all kinds of weirdness in the scripting part of the page, like the bit that says node.outerHTML="\u003Cdiv id=\"localNotice\" lang=\"en\" dir=\"ltr\"\u003E\u003Cdiv[... most of this statement removed ...]\n\u003C/div\u003E\u003C/div\u003E"; with escaped DIVs in it, that only apply when the script self-modifies the page-source. 81.179.199.253 21:59, 13 March 2026 (UTC)

In fact, the rogue DIV only appears when viewing the transcluded Talk page within the main article. Viewing the Talk page directly doesn't seem to show it (or have it in the same bit of the respective HTML source), which adds to my belief that it's a run-on tag (not?) being opened as part of the Comic page's definition. 81.179.199.253 22:02, 13 March 2026 (UTC)

Jupiter, Venus, Mars (at its peak) and Sirius are noticeably brighter than the others. Mars, Antares and Betelgeuse are also quite red. Also if you look at planets through a telescope or good binoculars you can tell that they have a larger size (and some have moons). The others would be quite hard to tell apart without knowing their position.

Object	App. Mag	B-V (Colour)
Venus	-4.98 to -2.98	0.82
Mars	-2.94 to +1.86	1.33
Jupiter	-2.94 to -1.66	0.83
Saturn	-0.55 to +1.17	1.04
Mercury	-2.48 to +7.25	0.97
Sirius	-1.46	0
Procyon	+0.34	0.42
Antares	+0.6 to +1.6	1.83
Altair	+0.76	0.22
Betelgeuse	0 to +1.6	1.85
Vega	0	0
Polaris	+1.86 to +2.13	0.6

It would be interesting to see if these characteristics are at all present in the comic (it does look like Mars, Betelgeuse and Antares are red and Saturn is a little yellow so maybe the colours are right), or what the comic should look like if they are not --22:50, 13 March 2026 (UTC)Sameldacamel34 (talk)

According to the Wikipedia page to proper motion, it is defined relative to the center of the solar system. So having a proper motion of zero makes the sun stand out indeed. 84.115.169.154 04:50, 14 March 2026 (UTC)

Err. proper motion is "relative to the center of mass of the Solar System," aka the barycenter, which is not the center of the Sun, but rather very close to it and sometimes outside of it. So, I think, (and I am definitely inexpert here), the [center of the] Sun is rather rapidly moving in an angular fashion about that point, far more so than any other object, whose angular movement around that point is much slower. Just like if you are one foot away from the north pole and wandering aimlessly, you can very quickly change your longitude from +90° to –90° in a step or two. So, I think, the Sun does indeed have "high proper motion," not "zero proper motion." But someone please correct me. Also, I (earlier) tried to explain proper motion in the last graf of the article and I suspect I did a poor job (possibly also inaccurate), so I'd appreciate someone with the, err, proper expertise fixing it up. JohnHawkinson (talk) 05:00, 14 March 2026 (UTC)

Created a nice image using the explanations on this page (using Gemini)

Chart fixed by explanations here -- 2A09:BAC3:2FF0:28C:0:0:41:127 (talk) (please sign your comments with ~~~~)

The extremely high parallax of the Sun (324,000 arc seconds if I calculate correctly) swamps out any proper motion. 2600:1001:B008:1230:9C83:B115:90B1:6038 12:12, 14 March 2026 (UTC)

Err…wutt? Again, I am not a domain expert or even really a domain user, but…

(a) A single object cannot have a "parallax." Parallax is a measure of error between two viewpoints (line segments), or perhaps between three points in space (the far object and two eye positions). Assuming the Sun is the far object, what are the other reference points or lines? If one is the Earth (a pretty big if ) then what is the other?

(b) 324,400 is 90 degrees, a right angle. "The Sun has a parallax of 90 degrees" is not a concept that makes sense to me.

Maybe I'm misunderstanding though? JohnHawkinson (talk) 13:20, 14 March 2026 (UTC)
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