Science1 publisher2 min readPublished
APOD announces its move to science.nasa.gov/apod in a line under the Cocoon Nebula
NASA's daily astronomy page told readers, in one sentence at the foot of an image explanation, that its main site is changing address. The change has no announced date, so anyone maintaining links is working without a deadline.
The Scientist · Science desk
What happened
- The 21 September Astronomy Picture of the Day entry tells readers that APOD's main NASA site is moving from apod.nasa.gov to science.nasa.gov/apod.
- The announcement sits inside the daily post, one line below the explanation text and immediately above the line previewing the next day's image.
- The image itself is a wide field covering more than two degrees of the constellation Cygnus, centered on the Cocoon Nebula, a compact star forming region.
- The page also bills tomorrow's picture as a triple eclipse, so the daily cadence is continuing while the address changes.
Compiled by The ScientistSomething wrong?How this is made
Why it matters
- decision Anyone maintaining a link, an embed or a scraper aimed at apod.nasa.gov now picks their own cutover date, because NASA has not published one. Doing that work before the old address stops answering is the cheap version.
- exposure Every consumer that hard-codes the old hostname, including the classroom links and archive bots that fail silently, depends on an arrangement between the two addresses that the page does not describe.
- constraint Because the only notice is a sentence inside one day's post, readers who meet APOD through mirrors, feeds or reposted images may never see it, and the burden of noticing falls on whoever reads the source page.
Moving a site to a new hostname breaks whatever was pointed at the old one, unless redirects hold. The notice on the 21 September page gives the destination: "APOD's main NASA site is moving: From apod.nasa.gov to science.nasa.gov/apod" [2]. It does not include a date for the change, and it does not say what will happen to requests sent to the old hostname [12].
The notice describes the thing being moved as APOD's "main NASA site" [2], which distinguishes it from whatever else serves the same content. The destination is already live: the entry carrying the notice is published on NASA's science site [1].
Changing one link takes a second; finding every place a hostname was typed into a syllabus, a feed reader, a bookmark bar or a nightly scraper takes longer.
The astronomy under the notice is a nice piece of wide-field imaging. The bright central head of IC 5146 spans about 10 light years, while the dark dusty tail runs nearly 100 [4][5]. Both parts sit about 2,500 light years away [6], so the tail is roughly ten times the length of the head at the same distance [13]. A bright star near the center of the nebula likely supplies its power and helps clear out a cavity [7].
The comet resemblance is a matter of outline. Emission and reflection light up the compact head on the lower right, with a long trail of interstellar dust clouds running off to the left, and the whole complex therefore looks a bit like a comet [10] even though the head and the tail lie at the same distance [6]. The filaments in that tail are dark in visible light and hide stars in the process of forming [8].
The picture was captured in July from Death Valley, California [9].
What to watch
- Whether a dated cutover for apod.nasa.gov appears in a later daily post or on the new page.
- Whether requests to apod.nasa.gov, including per-day archive pages, redirect to the new path once the move happens.
- Whether the feed addresses used by readers and scrapers change along with the main site.