First thought is wondering about what sort of light pollution levels - or not - Lovecraft had in Providence, and what sort of views he got of the night sky relative to modern-day viewers. I know he has written a lot about his astronomy experiences, and in newspaper articles. But it can be difficult at times to reconstruct the clarity with which people in the past could view the night sky, unlike today's heavily light-polluted era.
And although the narrator clearly isn't Lovecraft, it's hard not to view this astronomical story as a personal one for him, given his enthusiasm for astronomy. I had to look up "Charles' Wain" though, because that's not a name for the Plough (as it is known the UK) or Big Dipper (as in the US) I was familiar with.
And now I'm looking up the latitude of Providence, wondering if it ever saw the aurora borealis. It's 41 degrees north. I live somewhere 56 degrees north, and we rarely see aurora, though in my city today there is much light pollution. Aurora are much more visible further north in Scotland, including in the Orkneys and Shetlands. Researching further I see there was an aurora in New England in 1918. Chris Perridas has written extensively about its links to this story.
Frustratingly though I don't find the story flows that well. The opening section re the astronomy is a bit heavy handed with stars etc, even for astronomically-inclined me. And then the shift to the description of the city is too jarring, and also surprisingly repetitive. This section also has an unusually fantastic bent for Lovecraft, though that's perhaps to be expected for a quasi Dreamlands story. But the series of fantastical names - of places, people and creatures - doesn't pull me into the story, so much as push me away from it.
But I do rather like the ending, where the narrator returns, of a sort, to the real world. Or is it real? I don't always like to see stories structured like this, but it can be an effective way to wrap things up, while still leaving some questions unanswered.