Wikipedia talk:WikiProject Astronomy

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WikiProject Astronomy (Rated Project-class)
WikiProject icon Wikipedia:WikiProject Astronomy is within the scope of WikiProject Astronomy, which collaborates on articles related to Astronomy on Wikipedia.
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NGC 479

Just curious what everyone's thoughts are regarding our newest article on NGC 479, which currently has more pictures than text (four images, three sentences). I ask mainly because I got reverted when I removed the gallery and want to know if I was justified or not. Primefac (talk) 03:02, 8 October 2017 (UTC)

A duplicate of the infobox image, a simulated non-free image with no fair-use rationale, and a copyrighted image that will be deleted very shortly? That gallery is living on borrowed time. Lithopsian (talk) 10:12, 8 October 2017 (UTC)

How to convert geocentric to geographic coordinates?

Does anyone know how to convert geocentric to geographic coordinates? Context: I'm struggling to find the algorithm to convert the locations of astronomical observatories to geographic coordinates in order to display them in the List of observatory codes with template {{coord}}. Thx, Rfassbind – talk 01:14, 18 October 2017 (UTC)

Just guessing: I think the sine is the sine of the angle of the observatory from the centre of the earth. So take the inverse sine to get the latitude ... if the earth was a perfect sphere, so it won't be accurate to many digits. It gives reasonable answers for London, Paris, and Toronto. Tbayboy (talk) 13:16, 18 October 2017 (UTC)
It seems MathWorks has a function to do it, but you would still need to know rho (geocentric distance) for each observatory. Do you have that?   ~ Tom.Reding (talkdgaf)  13:25, 18 October 2017 (UTC)
In case you guys like to take a closer look, there is already an opensource project on github that converts from/to MPC's parallax constants (rho_cos_phi, rho_sin_phi). Unfortunately, all I get are gibberish results when I do the calculation for an actual observatory (PS: I'm assuming an average value of 6367447.5 for "height_in_meters").Rfassbind – talk 17:39, 18 October 2017 (UTC)

──────────────────────────────────────────────────────────────────────────────────────────────────── I found an algorithm to convert MPC's parallax constants to geographic latitude in degrees for some astronomical observatories (here). My calculated location is within approx. 100 meters from most locations given in the corresponding observatory articles on Wikipedia. However, all locations are systematically off by 20 kilometers or so, for which I do correct. And honestly, I don't know what the hell I'm doing. So if you have an improved/alternative algorithm (i.e. something that can be used to actually calculate coordinates) then I'd be happy to learn about it. Thx, Rfassbind – talk 01:35, 31 October 2017 (UTC)

Starbox parallax calculations

Do we know if the Starbox parallax calculations are accurate? I took a look at Beta Muscae, which has a parallax of 9.55±0.41. If I did the math right, this corresponds to 104.712±4.495 pc which matches the 105±4 listed in the article after rounding. However, when I scale that distribution to light years (× 3.2616), I get 341.53±14.66 pc (342±15), which doesn't match the article value of 340±10 after rounding. Perhaps it underwent significant figure truncation? Praemonitus (talk) 19:43, 19 October 2017 (UTC)

The distances calculated from parallaxes are rounded based on the parallax margin of error. This is done by Template:ErrorBar2. In short, the distance is rounded to the significant digit comparable to the margin of error (slightly fudged since it is the reciprocal of the actual margin of error). For example, if the margin of error in the distance is at least one but less than 10 then the parallax is rounded to the nearest whole number. If the margin of error is at least 10 and less than 100, it is rounded to the nearest ten. Since light year margins of error are inevitably bigger than parsec margins of error, light years are often rounded to fewer significant figures than parsecs. Maybe they should both be founded to the same precision? Don't see that it would cause any harm, and might save some confusion? Lithopsian (talk) 20:18, 19 October 2017 (UTC)
Okay. Well it would be good if the results matched what you get with the Convert template. Thanks. Praemonitus (talk) 22:23, 19 October 2017 (UTC)

GJ 1068

GJ 1068 was nominated for deletion and was closed as delete, but it never got deleted. Was it just forgotten and left there, or is there some reason why it hasn't been deleted? Loooke (talk) 19:39, 24 October 2017 (UTC)

It was deleted by @Joyous!: on 4 December 2017, then a new article at the same title was started by @I-CANT-THINK-OF-USERNAME!: on 23 October 2017. Thanks. Mike Peel (talk) 19:56, 24 October 2017 (UTC)
CSD'd. Headbomb {t · c · p · b} 20:42, 24 October 2017 (UTC)
Deleted. Graeme Bartlett (talk) 22:59, 24 October 2017 (UTC)
These articles also appear to be of dubious notability: Gliese 393, Gliese 555, Gliese 638, Gliese 693, Gliese 754, Gliese 784, Gliese 908, Gliese 1002, and GJ 3737. Most of the references just appear to be to various star catalogues. Praemonitus (talk) 21:04, 24 October 2017 (UTC)

Discussion at List of largest stars

I have started a discussion regarding the creation of some guidelines for the List of largest stars, which has seen a bit of edit warring recently. Please join in the conversation and give your thoughts. Thank you. Primefac (talk) 12:47, 26 October 2017 (UTC)

Algorithms for Julian Day

I have launched a Request For Comment at Talk:Julian day#Request For Comment on presentation of algorithms, after a long discussion with another editor. Basic'ly we agree that a couple of algorithms will work correctly if one "rounds" certain quotients toward minus infinity whether they are positive or negative, but the person whom we cite for the algorithms didn't say that, so the other editor wants us to say that the algorithms are only good for positive Julian Day. We also disagree about whether to write one of the algorithms in a simple way, or using a table of constants instead. Eric Kvaalen (talk) 08:03, 31 October 2017 (UTC)

The RFC is at Talk:Julian day#Request For Comment on presentation of algorithms. Eric Kvaalen I would suggest you rewrite to RFC to state what the issue is as you have explained here. Without knowing the RFC involves two alternatives it sounds like you are just asking if it is OK to present something that is wrong. StarryGrandma (talk) 20:04, 31 October 2017 (UTC)
@StarryGrandma: Thanks for the advice and for correcting my link! I am editing my link above as well (from "Day" to "day"). Eric Kvaalen (talk) 07:15, 1 November 2017 (UTC)

List of craters on Mars named after people

The discussion at Talk:List of craters on Mars named after people#Requested move 28 October 2017 regarding proposed renaming of the main header listed above, may be of interest. —Roman Spinner (talk)(contribs) 01:36, 2 November 2017 (UTC)

Deletion discussion about Loren C. Ball

A deletion discussion regarding an amateur astronomer is taking place at Wikipedia:Articles for deletion/Loren C. Ball. Your input is requested. Primefac (talk) 16:17, 6 November 2017 (UTC)

It's on the Wikipedia:WikiProject Deletion sorting/Astronomy list, along with other astronomy-related AfDs. Praemonitus (talk) 21:03, 6 November 2017 (UTC)
So it is. I missed that. I will keep that in mind for future reference (though I will note that it wasn't until I posted here that the discussion suddenly received an influx of participants). Primefac (talk) 22:19, 6 November 2017 (UTC)
I didn't notice the most recent astronomy AfDs until your post, Primefac; thanks.   ~ Tom.Reding (talkdgaf)  22:26, 6 November 2017 (UTC)
I would never have noticed the AfD if not for this post. It's a good way of attracting additional comments to an AfD that needs them. Modest Genius talk 11:36, 7 November 2017 (UTC)

Change in sunspot articles

There is a discussion that has been started at Talk:Solar cycle 2, and your input is requested. It involves a change made to the sunspot numbers. Primefac (talk) 14:01, 10 November 2017 (UTC)

Science images from WSC2017

Please take a look in here about newly uploaded scientific images on commons during Wiki Science Competitions 2017.--Alexmar983 (talk) 06:27, 17 November 2017 (UTC)

"Planet Ten" and the Kuiper Cliff

At Planets beyond Neptune the newly proposed "Planet Ten" [1] is listed in the section "Kuiper Cliff". Does this planet function as the likely cause of the Kuiper Cliff [2] or is it not related? If it's not related, this proposed planet should be moved to a different section, instead of sitting in the Kuiper Cliff section, since that has had several proposed planets already that are to cause the Cliff. -- 70.51.45.76 (talk) 19:48, 24 November 2017 (UTC)

Disambiguation links on pages tagged by this wikiproject

Wikipedia has many thousands of wikilinks which point to disambiguation pages. It would be useful to readers if these links directed them to the specific pages of interest, rather than making them search through a list. Members of WikiProject Disambiguation have been working on this and the total number is now below 20,000 for the first time. Some of these links require specialist knowledge of the topics concerned and therefore it would be great if you could help in your area of expertise.

A list of the relevant links on pages which fall within the remit of this wikiproject can be found at http://69.142.160.183/~dispenser/cgi-bin/topic_points.py?banner=WikiProject_Astronomy

Please take a few minutes to help make these more useful to our readers.— Rod talk 13:12, 3 December 2017 (UTC)

I think they're all done now. Lithopsian (talk) 14:10, 3 December 2017 (UTC)
Or not, the page is now showing a shorter list. brb. Lithopsian (talk) 14:11, 3 December 2017 (UTC)
The fix tool doesn't find links inside templates. IC 4 is a problem, solution unclear. See Template:Catalogs. Lithopsian (talk) 14:35, 3 December 2017 (UTC)
I don't have s solution for that one, might be worth asking at WikiProject Disambiguation but thanks for sorting the others.— Rod talk 14:41, 3 December 2017 (UTC)

WP:AALERTS need some help on Community Wishlist Survey

Many of you use Article Alerts to get notified of discussions (PRODs and AfD in particular). However, due to our limit resources (one bot coder), not a whole lot of work can be done on Article Alerts to expand and maintain the bot. If the coder gets run over by a bus, then it's quite possible this tool would become unavailable in the future.

There's currently a proposal on the Community Wishlist Survey for the WMF to take over the project, and make it both more robust / less likely to crash / have better support for new features. But one of the main things is that with a full team behind Article Alerts, this could also be ported to other languages!

I know I can't imagine the project with the alerts. So if you make use of Article Alerts and want to keep using it, please go and support the proposal. And advertise it to the other astronomy projects in other languages too to let them know this exists, otherwise they might miss out on this feature! Thanks in advance! Headbomb {t · c · p · b} 14:45, 4 December 2017 (UTC)

Light-years away from ... (?)

While looking at articles about deep-space objects (NGC galaxies, for example) which are written by different authors, I noticed that there are at least 4 different approaches when it comes to writing about distances in light-years. Example:

...is a spiral galaxy approximately 40 million light-years away.
...is a spiral galaxy approximately 40 million light-years away from Earth.
...is a spiral galaxy approximately 40 million light-years away from the Solar System.
...is a spiral galaxy approximately 40 million light-years away from the Milky Way.

I am using "away from Earth" in my articles about NGC objects (one editor occasionally changes that to "away from the Solar System").

Is there a consensus which approach should be used?

Felix558 (talk) 07:53, 5 December 2017 (UTC)

I think "from Earth" is best. "away" alone violates NPOV, and what we measure is the distance to Earth. That is also a reference point that can be used independent of the object. Gaia will bring the uncertainty on the distance to Alpha Centauri in a range where the difference to "the Sun" starts to get interesting. --mfb (talk) 08:07, 5 December 2017 (UTC)
Yeah, what he said - "from Earth" Cas Liber (talk · contribs) 10:36, 5 December 2017 (UTC)
Thirded. Primefac (talk) 12:38, 5 December 2017 (UTC)
...how does "away" alone violate netural point of view? - The Bushranger One ping only 23:06, 5 December 2017 (UTC)
Away from what? From Proxima Centauri b? Sure, no one outside Earth or Earth orbit reads the Wikipedia (yet), but even the ambiguity between "from Earth" and "from the Sun" makes the undefined "away" potentially problematic. In the solar system this matters. --mfb (talk) 00:42, 6 December 2017 (UTC)\
....okay. - The Bushranger One ping only 08:34, 6 December 2017 (UTC)
Aren't these typically listed as heliocentric distances? In that case it would be away from the Sun. Praemonitus (talk) 18:03, 5 December 2017 (UTC)
I think it would depend on what the literature says. Of course, now that I think about it, I don't recall ever seeing a specified source (it's always just "located Xpc away"). Primefac (talk) 18:27, 5 December 2017 (UTC)
I do not understand what is all this about? For an object at such a distance even the best distance estimates have precision not exceeding 10%. So d=40 ± 4 million light-years. The size of Milky Way is ~0.1 million light-years. Does it really matter where this distance is measured from? From the Sun, alpha-Centauri, Orion Nebula or Westerlund 1 star cluster? Ruslik_Zero 20:17, 5 December 2017 (UTC)
Just measure from this point:
.
And include an exact time, because the Earth is rotating, and orbiting the Sun, which is orbiting the center of the Milky way, and the Universe is expanding, and...
Okay, just say "from Earth" cuz the rest is pointless. (Sorry, couldn't resist.) --A D Monroe III(talk) 21:03, 5 December 2017 (UTC)
Note that this means beings reading our Wikipedia on other planets will have to do their own additional corrections. Tough. --A D Monroe III(talk) 21:08, 5 December 2017 (UTC)
That is a very WP:CRYSTALBALLish issue though.TR 07:54, 6 December 2017 (UTC)
I'm not predicting that extra-terrestrial beings don't exist, just that we shouldn't cater to them. "Earth" covers everyone for EN WP. Let the little green men start their own LGM WP. --A D Monroe III(talk) 15:38, 6 December 2017 (UTC)
I think 'away' is fine on its own, unless the context calls for a more precise zero point (e.g. objects within the Solar System). As an analogy, aircraft altitudes just state the value, without needing to add 'above sea level' every time. However I don't think we need an overarching policy, this can be decided on a case-by-case basis. Modest Genius talk 12:26, 6 December 2017 (UTC)
"Away" by itself is needlessly imprecise with no benefit. For instance, when talking about several nearby galaxies, someone reading a bit quickly may think we're stating successive distances between the galaxies -- each is so far from the last. Adding "from Earth" has no detriment, and avoids a potential problem. (I'm okay with leaving it out in cases where space is very precious -- big tables or whatever.) --A D Monroe III(talk) 15:41, 6 December 2017 (UTC)
Context is probably key here as well. I was curious about how often each of these appeared, and found ULAS J0015+01. The entire paragraph makes no sense unless it says "... away from the Milky Way". Primefac (talk) 15:50, 6 December 2017 (UTC)
Agree on taking context into account; forcing a rule to ignore that would be disruptive. I'm assuming we'd apply this only as the default use when any might fit. --A D Monroe III(talk) 17:04, 6 December 2017 (UTC)
When it comes to describing deep-space objects (for example galaxies, like in my example above), context is the same in every article (distance measured from Earth). Yet all 4 approaches stated above are used by different authors, and that looks inconsistent, since those articles don't exist on their own - they are part of the same encyclopedia, which should have consistent way of describing same things in articles about same type of objects. Felix558 (talk) 22:21, 6 December 2017 (UTC)
In fact, at least 6 ways for describing distances of deep-space objects are currently used on Wikipedia:
Distance from... Examples
...light-years away. NGC 5668, Messier 95
...light-years away from us. NGC 3115, DDO 190
...light-years away from Earth. NGC 3021, NGC 498
...light-years away from the Sun. Coma Berenices (dwarf galaxy), NGC 4147
...light-years away from the Solar System. NGC 1, Sculptor Dwarf Galaxy
...light-years away from the Milky Way. NGC 1979
Felix558 (talk) 22:51, 6 December 2017 (UTC)
Each paragraph where this might be used defines its context; one style might be preferable over another in each specific context. I don't imagine that's usually the case, especially in the opening sentence of an article, so I'm fine with giving a default recommendation, and have stated it: "away from Earth". It's just that I'm not fine with making this a rule that must always be obeyed, regardless of the current prose in use or of any unique qualities of the particular subject. English isn't a programming language. --A D Monroe III(talk) 01:58, 7 December 2017 (UTC)
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