https://hackerpaper.kaipfister.de/p/0709.4281/Collected HN comments and submissions linking this paper.enMon, 02 Nov 2026 11:16:22 GMThttps://news.ycombinator.com/item?id=3310055urn:hackerpapers:mention:0709.4281:3310055Sun, 04 Dec 2011 06:45:59 GMT<p>Astronomers drove digital imaging sensitivity, so I reckon they’ve got it worked out. Skimming http://arxiv.org/pdf/0709.4281v1 , it looks like Ralph, the main visible-light camera, can distinguish between true blackness and a mere 3k photons per pixel, and at the margin can detect objects of magnitude 14. Coincidentally, that’s about the magnitude of Pluto from earth, and you can’t see it even with a small backyard telescope. So this instrument is less like a consumer camera and more like, say, night-vision goggles. This paragraph originally did the math for Pluto’s brightness wrong (thanks…</p><p><a href="https://hackerpaper.kaipfister.de/p/0709.4281/">Paper and discussion history</a>. A mention is not an endorsement.</p>astro-ph