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Rafael C, thank you for your reply! You wrote:
"These authors give the separation between the δ1 and δ2 Gruis as 17 arc minutes, and that between μ1 and μ2 Gruis as 18 arc minutes. So, Jonathan Nally’s numerical values are in the right range, but his units are wrong by a factor of 60."

Exactly. The article gives those separations for the deltas and the mus of Gruis in seconds of arc when they should be in minutes of arc. But that's not the end of it...

Further down in the article, did you notice this description for finding some nice galaxies:
"To locate the Quartet, sweep 1° 55′ northeast from Theta (θ) Gruis and you’ll first come across NGC 7552, followed 27" later in the same direction by 7582. A further 10" will bring the NGC 7590 and 7599 pair into view."

It doesn't make sense as written. If I am "sweeping" nearly two degrees from some star, then target objects with separations of 27" and 10" (seconds of arc again!) would be extremely close together, and there wouldn't be anything further to do to bring the "pair into view". And if I check any star atlas, the separations are clearly minutes of arc again, not seconds of arc. For example, flipping to chart 78 in the excellent "Sky & Telescope Pocket Sky Atlas" edited/curated by Roger Sinnott, the separation between NGC 7552 abd NGC 7582 is about a tenth of an inch --a clear visual separation-- and that's roughly half a degree at this scale.

Noticing Roger Sinnott's name here brings up another point that's not mentioned in the article --and really should be. The article uses the Wikipedia standard star chart for Grus which was original produced by S&T and also has IAU validation. And it's a lovely star chart, once again reflecting the fine curation of Roger Sinnott. But even in the sedate world of astronomy, change happens. When the IAU approved official star names, the old spelling Al Na'ir (mostly used in celestial navigation) was simplified to Alnair. This happened eight years ago. The star chart in the article has not been updated. Likewise the star chart in the Wikipedia article for Alnair has the same source and issue. It's not that the name should be changed in the star chart for some light article like this one, but I couldn't imagine not taking note of the change.

You wrote:
"An easy mistake to make, but one that a review by him or by his editor should have caught, even for someone unfamiliar with this constellation."

Yes. It appears that they're depending on the "fix it in post" model. Surely some well-meaning person (so the theory goes...) will come along and point out the errors soon after they appear, and then the article can be repaired. But clearly this is bad for reputation and bad for business. And how difficult would it be to perform minimal editing and fact-checking before posting an article like this??

Incidentally, not an error, but a flaw, the article says that you won't find Δ 246 in "your planetarium software". There's an important point here for anyone chasing double stars like this. There are traditional designations, some with initial Greek letters like this one. These are sometimes termed "obsolete" (yet still widely used today so not really the right word), and there are slightly more modern (1960s vintage!) versions of these so-called "discoverer IDs", and wouldn't it be nice if the article explained that? The star listed as "Δ 246" is also listed as "DUN 246" (these ASCII variants became necessary in the early decades of digitization when so-called ASCII was the only character set available --no Δ's!). Oddly enough, if you go searching for this star in "Stellarium", which is by a wide margin the most popular "planetarium software", you'll find it only under Δ 246, and there's no listing for DUN 246. These issues are obviously not the fault of the article, but they're exactly the sort of practical confusion that content in S&T used to excel at resolving.

Just one more (there may still be others). There's a little "ring nebula" in Grus. The article describes it as a "condensed object of magnitude 16.5 spanning only about 2 by 2 arcminutes" and says "a 6-inch telescope reveals its round form".

So which is it? Is the correct magnitude 16.5? Or can I see it in a 6-inch telescope? It's not both! :)

Frank Reed