Milky Way plane in IRCUT — CrowdSky coverage map

Which HEALPix Norder-5 tiles along the Galactic plane already hold stacked Seestar IRCUT data, and how much.

Next automatic update in 5h 59m 57s · due 21:06 UTC on 24 Aug · this page rebuilds every 6h

162tiles with data (of 2382 in the band)

6.8%of the plane band covered

273 hcumulative exposure

1,956stacked frames

Milky Way contoursGalactic band linesscroll or pinch to zoom · drag to pan · hover a tile for detail

Cumulative exposure per tile< 10 min10 min – 30 min30 min – 1 h1 h – 3 h3 h – 10 h> 10 h

Milky Way isophotes (5 levels, faint → bright)Galactic b = 0, ±10°

CrowdSky IRCUT coverage of the Galactic band |b| ≤ 10°, on HEALPix Norder-5 tiles (~1.8° each). Fill shows cumulative exposure; amber contours are Milky Way surface-brightness isophotes. Zoom and pan to inspect individual tiles.

Table view — the 25 best-covered tiles (all 162 are in coverage_norder5.csv)

Tile	RA	Dec	l (°)	b (°)	Exposure (h)	Stacks	Sub-tiles	Last observed (UTC)
1007	22h46m	+57°24'	106.7	-1.5	51.68	370	10	2026-08-15 02:00
6372	06h51m	-02°23'	215.0	-1.3	16.26	69	2	2026-01-21 04:10
3681	06h11m	+23°19'	187.7	+2.2	14.28	85	3	2026-03-07 21:15
1612	21h32m	+48°08'	92.2	-2.5	13.55	73	2	2026-08-14 23:31
678	22h10m	+63°27'	106.0	+6.0	11.78	64	3	2026-08-09 02:29
11401	10h43m	-58°55'	287.0	-0.1	10.57	61	3	2026-02-06 17:44
2348	20h21m	+38°41'	76.7	+1.2	7.41	45	8	2026-08-14 21:03
1843	20h42m	+45°00'	84.1	+1.7	7.40	56	4	2026-08-14 22:35
3755	20h04m	+23°19'	61.8	-4.2	7.07	85	2	2026-07-30 23:44
2653	05h26m	+34°14'	173.3	-0.6	6.89	47	6	2026-03-04 22:30
2991	20h49m	+31°23'	74.2	-7.7	6.87	61	3	2026-07-14 02:14
2524	05h21m	+35°41'	171.5	-0.7	6.06	44	4	2026-03-04 20:44
2221	20h26m	+40°14'	78.6	+1.2	5.93	51	13	2026-06-08 23:44
3369	19h47m	+27°17'	63.3	+1.1	5.62	27	1	2026-07-25 21:44
8609	18h11m	-23°19'	7.7	-2.2	5.50	50	5	2026-05-03 19:44
1964	20h14m	+43°24'	79.9	+5.0	4.39	22	1	2026-06-19 20:59
1841	20h18m	+45°00'	81.6	+5.2	4.32	21	1	2026-06-19 21:14
1967	20h48m	+43°24'	83.6	-0.1	4.18	24	1	2026-06-16 01:44
2347	20h09m	+38°41'	75.5	+3.1	4.16	31	4	2026-08-16 00:15
8608	18h00m	-23°19'	6.5	+0.1	3.93	33	4	2026-05-03 17:29
2607	20h54m	+35°41'	78.4	-5.9	3.78	61	2	2026-08-14 23:44
3295	05h54m	+27°17'	182.4	+0.8	3.70	23	2	2026-03-13 22:14
2525	05h32m	+35°41'	172.7	+1.1	3.47	38	4	2026-03-04 23:00
5667	18h39m	+04°47'	35.8	+4.9	3.47	17	2	2026-07-20 20:14
2780	05h21m	+32°48'	173.8	-2.4	3.29	26	2	2026-03-04 20:44

How this map is made

One public request, no pixels. The only input is CrowdSky's sky-coverage feed (GET /api/sky_coverage.php) — a materialized summary of every stacked frame, one row per (HEALPix tile, filter) with cumulative exposure, stack count and first/last observation. No FITS files are downloaded and no API key is needed.
Re-tiled from Norder 7 to Norder 5. The feed is tiled at CrowdSky's native Norder 7 (NSIDE=128, ~27.5′ tiles, finer than the Seestar field of view). Those rows are summed into Norder 5 tiles (NSIDE=32, ~1.83°) — coarse enough to read as a map. HEALPix nests exactly, so each fine tile belongs to exactly one coarse tile.
Filter. Only IRCUT frames count. CrowdSky reports the same physical UV/IR-cut filter as both IR and IRCUT (a firmware naming difference); both are folded together.
Band selection. A tile is shown if it overlaps the Galactic band |b| ≤ 10°, tested on its centre plus 16 boundary samples. Overlap rather than centre-inside, so the band edge follows tile boundaries instead of clipping tiles that genuinely hold in-band data.
Projection. Plate carrée in equatorial J2000, right ascension increasing to the left. Tiles that straddle RA = 0 are drawn on both sides of the seam.
Milky Way contours. Five surface-brightness isophotes, vendored from d3-celestial (github.com/ofrohn/d3-celestial), data/mw.json (BSD-3-Clause, (c) 2015 Olaf Frohn) and decimated for the page. They are reference geography, not CrowdSky data.

Caveats: cumulative exposure is summed over heterogeneous Seestars and sky conditions, so it measures effort rather than depth; and the per-tile Seestar count is a lower bound, because the feed counts distinct units per Norder-7 tile and the same unit usually appears in several of a coarse tile's children.

Generated 2026-08-24 15:06 UTC · CrowdSci