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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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Please review Herbig-Haro object for GA criteria[edit]


Herbig-Haro object is a former feature article within the scope of WikiProject Astronomy, and was delisted mainly due to insufficient citations. I have been improving the article for some time and citation concerns have been addressed, along with some other improvements. As such, I have nominated it for GA and would like to request willing editors to review it.

Best regards--ubedjunejo (talk) 22:56, 18 February 2018 (UTC)

A link to a DAB page[edit]

Baryon asymmetry links to the DAB page metagalaxy (as a pipe from metagalaxies). Can any expert here help solve the problem? Narky Blert (talk) 12:30, 20 February 2018 (UTC)

I think the inclusion of that DAB link is a misunderstanding. Metagalaxy is not a synonym for anti-matter galaxy. Rather it refers to an amalgamation of galaxies, anything from a galaxy group up to the entire observable universe. For a while, it was theorised that some of these metagalaxies (ie. groupings of galaxies) might be composed of anti-matter and a description of that could have been mis-read. Lithopsian (talk) 14:38, 20 February 2018 (UTC)

Main image of Pleiades under copyright?[edit]

Was just browsing the article on the Pleiades, and I noticed that the main image is from the Digitized Sky Survey, supposedly under public domain because it's sourced from a NASA release. I was surprised, because I thought DSS images were under copyright, and confirmed that they indeed are. I'm not an expert in copyright info, but something seems inconsistent here. Does NASA using the file mean it's no longer under copyright? Did they make a mistake in using a copyrighted file without permission, or did wikipedia make a mistake in assuming that their use permits free usage. Something overall seems somewhat fishy here. BTW while we're at it, there's a few other images coming directly from DSS and such without any such NASA backup in [1], such as this and this. exoplanetaryscience (talk) 01:39, 25 February 2018 (UTC)

From what I can find, File:Pleiades large.jpg was created by the STScI at Palomar, and is thus released from copyright. We use {{PD-USGov-NASA}} because STScI operates under NASA contract NAS5-26555. I cannot speak for other images in Commons:Category:Digitized Sky Survey, however, and it's likely their individual releases would have to be determined. It appears most of the DSS is based off scans by STScI of photographic plates produced by the UK Schmidt Telescope. I don't see how these could be justified for our use, but I could be missing some other detail. Huntster (t @ c) 02:41, 25 February 2018 (UTC)
From what I can find, File:Pleiades large.jpg was created by the STScI at Palomar, and is thus released from copyright.
Is that true though? Indeed the DSS Copyright Information expressly states the Palomar data is "copyright © 1993-1995 by the California Institute of Technology" and at the same time as referencing the NASA contract. IANAL, but our very own article on copyright status of work by the U.S. government states in the opening paragraph;
Publication of an otherwise protected work by the U.S. government does not put that work in the public domain. For example, government publications may include works copyrighted by a contractor or grantee; copyrighted material assigned to the U.S. Government; or copyrighted information from other sources.
This would imply contracted work is not necessarily free of copyright. ChiZeroOne (talk) 12:13, 25 February 2018 (UTC)
A very dubious area. There are lots of images hosted at places like STScI, which have been constructed from copyright images (eg. DSS) with the addition of other wavelengths or annotations. Without being an intellectual property lawyer and examining the small print in minute detail it can be difficult to tell what the status of these images is. Wikipedia editors have a terrible habit of assuming everything is free unless there is a massive copyright symbol stamped on it in red, but then I guess it isn't their necks on the line. In this case, there is an image use link right next to the image. The linked page contains the usual mystifying text about images being credited to STScI being free-to-use and other images *possibly* being copyright. In this case the image is unhelpfully credited to "NASA, ESA, and AUAR/Caltech". The credit isn't explicitly STScI, but those institutions are collectively and effectively STScI; they certainly aren't the DSS copyright holders for that image. I'd say we're good with this one, but then it isn't my neck on the line and I'm not an intellectual property lawyer. Other cases you'll have to take on their merit, and if an apparently legitimate image owner such as this does state the wrong license terms I don't think we can double-guess them. Lithopsian (talk) 17:03, 25 February 2018 (UTC)
Exactly. At the end of the day we have to do our due diligence, but if the releasing entity who is otherwise credible has screwed up their copyright (or lack thereof) claim, there's not much we can do with it. I'm a big proponent of the precautionary principle at Commons, but in situations like this we'd end up deleting a vast swath of the database if we disregard their own statements. Huntster (t @ c) 13:27, 26 February 2018 (UTC)
Just for reference, DSS (not to be confused with the entirely separate and now free-to-use SDSS) images in general are copyright. There is no question about that. I delete maybe one a week from Commons, but I suspect there are dozens or even hundreds still on there. They are widely available through apparently-free software like Aladin but are still copyright. I don't know what the mechanism is for releasing particular DSS images into the public domain as is apparently done by by institutions like STScI and ESO, but I can only assume it is legitimate. Lithopsian (talk) 17:07, 25 February 2018 (UTC)

Template:Wikidata redirect on all MP#Rs with a Wikidata item?[edit]

As Paine Ellsworth started doing, I figured I'd follow-through and place {{Wikidata redirect}} on all of our main Minor Planet #Redirects which have a Wikidata item currently associated with it (secondary/tertiary/etc. #Rs shouldn't have a WD item anyway). Yea/nay?   ~ Tom.Reding (talkdgaf)  19:00, 25 February 2018 (UTC)

Hi Tom, and thanks again for helping! I am working through Category:Redirects connected to a Wikidata item, and I have finished the "early" minor planets that are sorted there. I'm neutral on whether or not redirects should have WD items, though I don't see anything wrong with it. I'm placing the {{Wikidata redirect}} rcat on those category entries because I think it's important that editors are readily informed about it when they click on a WD redirect link. Thanks again!  Paine Ellsworth  put'r there  19:34, 25 February 2018 (UTC)
Oh I wasn't even aware of that tracking cat! I'm surprised it's so low (~2600)...and most of them aren't even MPs...   ~ Tom.Reding (talkdgaf)  21:16, 25 February 2018 (UTC)
It's worth noting that whether or not Wikidata sitelinks to redirects are good or bad is an open discussion, see d:Wikidata:Requests for comment/Allow the creation of links to redirects in Wikidata. Personally, I wouldn't spend too much time adding/removing them until that's been decided. Thanks. Mike Peel (talk) 20:09, 25 February 2018 (UTC)
Excellent! Thank you; that's relevant for many projects.   ~ Tom.Reding (talkdgaf)  21:16, 25 February 2018 (UTC)

Object type of M104?[edit]

Please see Talk:List of Messier objects#Object type of M104. Input is welcome. -- Toshio Yamaguchi 10:38, 3 March 2018 (UTC)

Deletion discussion of Spiral galaxy dynamics[edit]

Article Spiral galaxy dynamics has been nominated for deletion discussion. Editors interested in the discussion are welcome to share their views on the deletion discussion page. Thanks --UbedJunejo (talkcont) 19:10, 11 March 2018 (UTC)

Plea from a simpleton[edit]

Is there a simple red-shift-number-to-universe-age table hereabouts? If not, and it's not at Redshift, could someone create a barebones one there? The talk page comment is at Suggestion to help the simpletons. Shenme (talk) 20:43, 12 March 2018 (UTC)

It isn't fixed, so a table might be inappropriate although certainly you can find them (eg here). Hubble's law contains a list of reported values (or ranges) for the Hubble Constant that relates redshift to distance, and also has a graph that effectively shows you the relationship. Lithopsian (talk) 20:46, 12 March 2018 (UTC)
It depends on the cosmology you adopt. There's a reason why astronomers mostly stick to reporting the redshift (an observable) rather than age (an inferred model-dependent quantity). See [2] for some tools for doing the calculation. To answer your original question, anything above a redshift of 6 is within a Gyr of the Big Bang, roughly and assuming concordance cosmology. Modest Genius talk 14:40, 16 April 2018 (UTC)

redirect to Messier's catalogue article[edit]

Hi, I have just discovered this redirect made in 2004 and it actually confused me a little bit. Am I the only one?

It is linked to the original title of the catalogue, Catalogue des nébuleuses et des amas d'étoiles, so a translation of the second half... but in my experience noone knows it like "Nebulae and Star Clusters", using only the second half of it. IMHO, it does not ring a bell when you say it like that. I found it on google although not all in the first results, but I have asked around to other people with Ph.D. and the string "Nebulae and Star Clusters" is not understood as specific of this work, so how can anyone in practice search for it or use it as a redirect here? In facts, it is unused.

Plus, at the time galaxies were considered nubulae, but not now, so without "Messier" people might be confused about the meaning of the redirect, since some Messier objects are not nebulae or star clusters, and many other clusters are not in the Messier catalogue. Some people actually were, before searching and reading and understanding that it was part of the catalog's original name. I have discovered it putting "Nebulae" in the search bar and originally I though that it was a redirect to some list of pages on the whole topic. Actually, the astronomer in my poll was more confused about it when I showed it, which is fun to think about. I could guess almost immediately there was some historical reason (the original title), he couldn't.

I am really curious: are me and my friends the only ones to feel this way? that is, to think this redirect confuses more than it helps?--Alexmar983 (talk) 22:39, 13 March 2018 (UTC)

Alexmar983, you're welcome to send it to WP:RFD if you do not think it is useful. However, being a partial match for a title of a book written by Messier is (if I remember correctly) one of the acceptable reasons to have a redirect. I could be misremembering, though. Primefac (talk) 11:30, 14 March 2018 (UTC)
Primefac I let the project decide, if people here agree, I'll link this discussion to RFD, otherwise fine with me. it's just that after having spent 20 minutes to discuss it (someone had a boring night, I guess), adding 5 minutes to write here was no big deal. Do you think it's not confusing? if so, we keep it.--Alexmar983 (talk) 11:48, 14 March 2018 (UTC)
I mean, it wouldn't be the first thing I'd be searching if I was looking for Messier Objects (or his book), but I could certainly see someone thinking "it was something about nebulae and clusters..." so I couldn't say if it's useful overall. Pageview analysis shows less than 1 hit per week for the last year, which is quite a bit lower than the 200-300 seen by the article itself. Primefac (talk) 11:59, 14 March 2018 (UTC)
I saw that number, I cut that part to reduce the size of my commment... but still the question remained in my head. Are those readers actually looking for Messier's catalog when they click there? Or are they more similar to my case, that is typing "nebulae" and clicking on it from the scroll menu thinking it is some short string for a redirect to a list of summary pages? I guess we'll never know.--Alexmar983 (talk) 13:51, 14 March 2018 (UTC)
Not the most brilliant and necessary redirect I've ever seen, but I don't find it confusing. Follow it and you get to a type of nebula or star cluster. Possibly there is a better target for it? I don't see anything that would obviously mark it out for deletion, the criteria for allowing redirects are pretty loose. Boldly retargeting is almost always better than weeks of discussion that nearly always result in ... retargeting. New General Catalogue of Nebulae and Clusters of Stars? Don't double-redirect of course. Lithopsian (talk) 17:29, 14 March 2018 (UTC)
What about Catalogue of Nebulae and Clusters of Stars too :D? I feel that what is missing (or i cannot find) is a page where all possible catalogues are listed with some comments, that it is the page I would make a redirect too, the most honest one for a reader. Not a disambiguation page, that I assume it's correct if it is string-based, but a "content page".
I am not sure if there is a clear scientific word to encompass these diverse "non star deep-sky objects" (not my real field, sorry) but in general a list with some comments of the articles listed in Category:Astronomical catalogues (and similar subcategories or same-level categories) by year of creation or main author/project could be probably useful. The perfect redirect should direct to that.
Just a guess, of course. In my experience by field and language this type of confusions can be ignored for years, but sometimes it is useful to reveal if something "structural" is missing. Look for example at Template:Messier objects or Template:Caldwell catalogue who include the objects and some historical catalogues. i believe that that second part in those navboxes should be removed in a new separate navbox, to be further enlarged and improved over the years. That could be a future base also on an article-list of some types. You see that quite well when you open Herschel_400_Catalogue that has no navbox. Just a suggestion, of course. Sorry I cannot really help... maybe I can separate the navbox, it is a good "seed" to plant.--Alexmar983 (talk) 14:55, 15 March 2018 (UTC)

Units for equatorial coordinates?[edit]

I was trying to look up the location of Orion_(constellation), and the infobox says RA=5, dec=+5. I was not familiar with the equatorial coordinate system, so I clicked through and found that both RA and dec are angles. Shouldn't we provide the units for those angles? In math, angles without units are typically taken to be in radians, but here I guess RA is in hours and dec is in degrees (correct?). The usage instructions for {{infobox constellation}} recommend to use the templates {{RA}} and {{DEC}} which add the proper units automatically. For experts, the assumed units are probably clear, but adding them won't hurt and would make things easier for laymen. Cheers, AxelBoldt (talk) 21:32, 14 March 2018 (UTC)

The correct units are hours (h) and degrees(°). I would have thought the infobox should be adding them. The documentation says those fields expect a range and should use the {{RA}} and {{DEC}} templates, which would provide the units. A spot-check suggests this isn't happening for many constellations, but is for some (eg. Pavo (constellation)). Lithopsian (talk) 21:40, 14 March 2018 (UTC)
Infobox constellation does not automatically add RA and DEC. Given that either single center coords or ranges are accepted, it wouldn't be practical for the infobox to automatically add the formatting. Huntster (t @ c) 01:26, 15 March 2018 (UTC)


Hi, I created the article K2-155d but I’m planning big improvements to the article. Today is just a start. Anything I should add in the article (if so feel free to list them down and sources I can use for each of them)? LovelyGirl7 talk 00:48, 22 March 2018 (UTC)

I suggest adding links for technical terms like habitable zone and insolation. Is there any information about the orbital eccentricity? Thanks. Praemonitus (talk) 03:35, 22 March 2018 (UTC)
@Praemonitus: I’ve wikilinked the 2 you told me. However, there isn’t really any information about its orbital eccentricity. I can’t find a source that mentions it’s orbital eccentricity, but you could let me know below for a source mentioning it as well as the link for it. Anything else I can add to the article to continue improving it? —LovelyGirl7 talk 11:56, 22 March 2018 (UTC)
@LovelyGirl7: Thanks. I checked the Hirano et al. (2018)[3] paper and, if I'm reading it correctly, the authors just assumed low eccentricity based on Van Eylen & Albrecht (2015).[4] Praemonitus (talk) 15:32, 22 March 2018 (UTC)
@Praemonitus: I’ve added the source and a sentence saying it. How’s the sentence so far? Also, what else do you think I should add in the article, besides eccentricity (and sources for sugggestions)? I have 2 sections in it as well. —LovelyGirl7 talk 16:33, 22 March 2018 (UTC)
@LovelyGirl7: Well I don't want to be discouraging here, but for an object with a single scientific study, I'm not sure there is a lot more you could add. At best you can probably expand on the existing information a bit. But I could easily be mistaken, of course. Praemonitus (talk) 15:52, 23 March 2018 (UTC)

Sidereal time article improvements[edit]

I have added Sidereal time to the project, have updated the article to use modern, 21st century definitions. I would appreciate it if someone would give the article a rating, and would appreciate suggestions for further improvements. Jc3s5h (talk) 12:38, 24 March 2018 (UTC)

FLC:List of nearest exoplanets[edit]

Hey guys, if anyone is interested, I would appreciate feedback for this relevant FLC. Nergaal (talk) 17:29, 25 March 2018 (UTC)


I just created the stub High-Energy Replicated Optics because I saw a reference to it and wanted a page to explain it. I don't really know anything about astronomy, much less high-energy x-ray astronomy, so eyes would be welcome. - CRGreathouse (t | c) 19:59, 27 March 2018 (UTC)

Re Draft:NGC 2202[edit]

I've tagged it with the astronomy wikiproject, did you receive an article alert for this?

It's outside of my knowledge area, would be nice if someone expanded the article or confirmed whether it's appropriate for inclusion in the main namespace.

Thank you.

--Gryllida (talk) 01:32, 28 March 2018 (UTC)

I added an infobox, but according to a note in Simbad this object may not even exist. Praemonitus (talk) 02:53, 28 March 2018 (UTC)

Stars and planets and notability[edit]

So, I just saw a new article, WASP-79b, about an extrasolar planet, but I notice that its star, WASP-79 does not have an article. So, if an extra-solar planet is notable, does that mean its star is notable too? Oiyarbepsy (talk) 13:04, 30 March 2018 (UTC)

No. Many years ago, it was rare for a star to have a known exoplanet, so that in itself tended to create coverage. No longer, there are now thousands of stars with exoplanets and most of them are just entries in a database. However, stars with notable exoplanets tend to have been studied a little more than your average star and it may be relatively simple to create a reasonable article. WP:NASTRO still applies but personally I'm a little more relaxed about an article that actually says something useful about its subject and doesn't quite meet the strict criteria. A one-liner (with or without starbox) just because the star has an exoplanet tends to go straight to AfD. In this case, there is zero independent coverage of WASP-79, so certainly not notable other than its exoplanet, hard to imagine what you'd say about it that isn't already in the short paragraph in WASP-79b; the existing redirect seems appropriate. Lithopsian (talk) 13:26, 30 March 2018 (UTC)

Urgent help needed to fix 5 cosmology errors related to the Big Bang in the article Chronology of the universe[edit]

There are quite a few errors/ambiguities in our article Chronology of the universe. Some are actively misinforming readers. They need someone who can fix them.

Link: Talk:Chronology of the universe#Technical errors/ambiguities on the page, knowledgeable editing required to fix them

Please look! Thank you. FT2 (Talk | email) 06:52, 13 April 2018 (UTC)

Duplicated subject?: Yarkovsky effect[edit]

Hello. I came across two articles that seem to be a duplicate of the same subject: Yarkovsky effect, and Yarkovsky–O'Keefe–Radzievskii–Paddack effect. Are they different phenomena or should they be merged? Thanks. BatteryIncluded (talk) 18:33, 13 April 2018 (UTC)

Different things. Technically, strictly. The Yarkovsky effect is a linear force. The Yarkovsky–O'Keefe–Radzievskii–Paddack (YORP) effect is a torque, rotational force. This could be explained better in the articles, and potentially they could even be merged since the mechanism behind the two effects is the same. Lithopsian (talk) 19:19, 13 April 2018 (UTC)
Related but separate effects, see e.g. [5]. They could merge into a Yarkovsky & YORP effects article, but I suspect that would increase reader confusion more than it clarified things. It's probably safest to keep them separate, but add some comparison with the other effect. Modest Genius talk 14:33, 16 April 2018 (UTC)

Category:LEDA objects and Category:PGC objects[edit]

Aren't these the same catalogue? If so, why are there two different categories for this? Loooke (talk) 23:34, 14 April 2018 (UTC)

They certainly would appear to be, but a SIMBAD search for LEDA 36252 (specifically mentioned in the LEDA page), doesn't include a PGC name. Primefac (talk) 00:08, 15 April 2018 (UTC)
I think PGC and LEDA names are unified in SIMBAD, which is why if you look up PGC 39058, which is mentioned in Principal Galaxies Catalogue, it gives one of the designations as "LEDA 39058". Loooke (talk) 14:00, 15 April 2018 (UTC)
Since LEDA basically turned into PGC, should we merge the former into the latter? I don't see how the one-paragraph page on LEDA can really be expanded, so it might be worth just chucking it into the PGC page. Would allow us to convert/merge the LEDA cat into the PGC cat. Primefac (talk) 15:27, 15 April 2018 (UTC)
Yeah, that seems like a good idea. Loooke (talk) 02:39, 19 April 2018 (UTC)