Sky transparency — night of 28–29 September 2026

Cloud arrived at 22:45 — detected by the all-sky camera, independent of N.I.N.A. Before it the sky ran at index 100 (IQR 90–111); after it 100 (IQR 44–115). 26 of 85 light frames landed before the cloud. 20 of 21 failures are attributed to cloud; 1 remain unexplained and deserve a look. Guiding ran at 0.94″ RMS before the cloud and 1.37″ after; the worst minute was 23.19″ at 04:26. The 22:43 autofocus run fitted its curve on almost no stars and should not be trusted. Morning sky flats: 60 frames (H 20, O 20, S 20), 05:50–06:02, auto-exposure 5.0–20.0 s.

Index before 22:45
100 · IQR 90–111
Index after 22:45
100 · IQR 44–115
Cloud onset (all-sky)
22:45 · independent
Errors after onset
20 of 21 · solve + PHD2
Guide RMS
1.24″ · RA 0.92 · Dec 0.83

Normalised transparency index, by filter

100 = that target and filter's own clear‑sky median (this night's own pre-cloud median). Shaded columns are autofocus runs; the first target is named at the top left and dashed vertical rules mark each target change; ticks along the base are errors.

H α O III S II ▲ Plate solve failed ◆ PHD2 error
05010015020020:0021:0022:0023:0000:0001:0002:0003:0004:0005:00% of clear-sky medianclear-sky baselineM 16→ M 16→ NGC 2030→ NGC 2030HOS

All‑sky background brightness

Mean luminance of the upper sky per all‑sky still — independent of anything N.I.N.A. recorded. The camera auto‑exposes, so this is an instrumental number, not photometry.

02040608020:0021:0022:0023:0000:0001:0002:0003:0004:0005:00Mean sky luminance (0–255)all-sky

PHD2 guiding

RMS tracking error per minute from the PHD2 guide log, taken about zero rather than about each minute's mean, so slow drift counts as error. 2432 guide frames over 7.9 h of guiding in 22 sessions; the gaps are slews, dither settles and autofocus runs, when PHD2 was not guiding. PHD2 discarded 117 further frames — usually a lost star. The worst minute (23.19″ at 04:26) is clamped at the top of the plot.

RA RMS Dec RMS ◆ PHD2 error
0.00.40.81.21.620:0021:0022:0023:0000:0001:0002:0003:0004:0005:00RMS guide error (arcsec)night RMS 1.24″RADec

All‑sky frames at the key moments

Times come from the still filenames, so they line up with the charts exactly.

All-sky at 19:21
19:21 · start of night
All-sky at 22:45
22:45 · cloud onset
All-sky at 22:45
22:45 · peak brightness 73.0
All-sky at 05:33
05:33 · end of night

Clear‑sky reference medians

The divisors behind the index — median detected stars per light sub before 22:45. NGC 2030 had no clear frames tonight and no clear history, so its divisor is its own whole-night median. Its index shows how the sky changed during that target, not how it compared with a clear sky.

TargetFilterMedian starsFramesSource
M 16H34612tonight, clear frames
M 16O5078tonight, clear frames
M 16S8186tonight, clear frames
NGC 2030H26920whole night, cloud included
NGC 2030O27220whole night, cloud included
NGC 2030S26719whole night, cloud included

Event timeline

All observatory events with their attributed causes.

PHD2timed-out waiting for guider to settleunexplained
solve failedASTAP plate solve failedcloud
solve failedASTAP plate solve failedcloud
solve failedASTAP plate solve failedcloud
solve failedASTAP plate solve failedcloud
solve failedASTAP plate solve failedcloud
solve failedASTAP plate solve failedcloud
AF failedautofocus run started 04:00:07 did not completecloud
PHD2Guiding stoppedcloud
PHD2timed-out waiting for guider to settlecloud
solve failedASTAP plate solve failedcloud
solve failedASTAP plate solve failedcloud
AF failedautofocus run started 04:19:18 did not completecloud
PHD2timed-out waiting for guider to settlecloud
solve failedASTAP plate solve failedcloud
solve failedASTAP plate solve failedcloud
AF failedautofocus run started 04:28:45 did not completecloud
PHD2Guiding stoppedcloud
PHD2timed-out waiting for guider to settlecloud
solve failedASTAP plate solve failedcloud
solve failedASTAP plate solve failedcloud
AF failedautofocus run started 04:41:47 did not completecloud
PHD2Guiding stoppedcloud
solve failedASTAP plate solve failedcloud
solve failedASTAP plate solve failedcloud
AF failedautofocus run started 04:51:01 did not completecloud
All 262 frames (excludes the 60 sky flats — no stars to detect)
TimeClassTargetFilterExpStarsHFRIndex
19:21:06autofocusM 16L5s3054.79—
19:21:21autofocusM 16L5s8181.92—
19:21:35autofocusM 16L5s7272.16—
19:21:50autofocusM 16L5s6082.74—
19:22:05autofocusM 16L5s4713.58—
19:22:25autofocusM 16L5s2994.77—
19:22:45autofocusM 16L5s5412.65—
19:23:05autofocusM 16L5s3164.01—
19:23:20autofocusM 16L5s2325.12—
19:23:35autofocusM 16L5s1996.07—
19:23:55autofocusM 16L5s8151.95—
19:31:17lightM 16H300s3254.0394%
19:36:18lightM 16H300s3453.97100%
19:41:49lightM 16H300s3254.2094%
19:46:51lightM 16H300s2944.4385%
19:52:54lightM 16O300s4525.0289%
19:57:55lightM 16O300s4595.0191%
20:03:16lightM 16O300s4714.9593%
20:08:18lightM 16O300s4514.9789%
20:14:30autofocusM 16S300s5875.57—
20:14:51autofocusM 16L5s4023.31—
20:15:11autofocusM 16L5s1428.14—
20:15:31autofocusM 16L5s1676.79—
20:15:51autofocusM 16L5s2195.33—
20:16:10autofocusM 16L5s2854.23—
20:16:31autofocusM 16L5s4403.12—
20:16:51autofocusM 16L5s5062.65—
20:17:11autofocusM 16L5s6492.22—
20:17:31autofocusM 16L5s6002.62—
20:17:50autofocusM 16L5s5202.94—
20:18:11autofocusM 16L5s4183.75—
20:18:30autofocusM 16L5s3324.64—
20:18:50autofocusM 16L5s6112.30—
20:24:59lightM 16S300s8184.15100%
20:30:29lightM 16S300s7704.2294%
20:35:31lightM 16S300s10343.49126%
20:41:44lightM 16H300s4423.30128%
20:46:45lightM 16H300s3783.59109%
20:52:52lightM 16H300s4093.44118%
20:57:54lightM 16H300s4233.40122%
21:03:40lightM 16O300s6773.53134%
21:08:42lightM 16O300s6023.72119%
21:14:11lightM 16O300s5074.00100%
21:19:13lightM 16O300s5344.01105%
21:25:14autofocusM 16S300s7223.93—
21:25:30autofocusM 16L5s4302.23—
21:25:45autofocusM 16L5s1075.93—
21:26:00autofocusM 16L5s1764.28—
21:26:15autofocusM 16L5s2303.63—
21:26:30autofocusM 16L5s3332.39—
21:26:50autofocusM 16L5s4732.12—
21:27:10autofocusM 16L5s4922.16—
21:27:30autofocusM 16L5s3972.73—
21:27:50autofocusM 16L5s2913.73—
21:28:05autofocusM 16L5s2324.42—
21:28:25autofocusM 16L5s5042.08—
21:34:33lightM 16S300s8513.38104%
21:35:51centeringM 16L5s8813.13—
21:36:12centeringM 16L5s8312.95—
21:36:46centeringM 16L5s12210.15—
21:37:06centeringM 16L5s1529.29—
21:37:32centeringM 16L5s5183.78—
21:37:45centeringM 16L5s5943.56—
21:37:55centeringM 16L5s5533.68—
21:38:19centeringM 16L5s6043.53—
21:40:23centeringM 16L5s8613.16—
21:40:34centeringM 16L5s8212.76—
21:40:45centeringM 16L5s7414.26—
21:47:02lightM 16S300s7333.8190%
21:52:33lightM 16S300s7063.7386%
21:58:46lightM 16H300s3473.69100%
22:04:15lightM 16H300s3223.8493%
22:09:16lightM 16H300s2944.0085%
22:10:15autofocusM 16L5s3122.31—
22:10:30autofocusM 16L5s757.21—
22:10:45autofocusM 16L5s705.44—
22:11:00autofocusM 16L5s1354.18—
22:11:15autofocusM 16L5s2292.98—
22:11:35autofocusM 16L5s3202.22—
22:11:55autofocusM 16L5s3682.10—
22:12:15autofocusM 16L5s3652.39—
22:12:35autofocusM 16L5s2752.97—
22:12:50autofocusM 16L5s1893.90—
22:13:05autofocusM 16L5s1754.75—
22:13:25autofocusM 16L5s2662.06—
22:19:35lightM 16H300s3463.48100%
22:40:34centeringNGC 2030L5s10.00—
22:40:43centeringNGC 2030L5s238.85—
22:40:52centeringNGC 2030L5s238.94—
22:42:07centeringNGC 2030L5s10.00—
22:42:16centeringNGC 2030L5s10.00—
22:42:25centeringNGC 2030L5s10.00—
22:43:55autofocusNGC 2030L5s122.09—
22:44:10autofocusNGC 2030L5s34.74—
22:44:25autofocusNGC 2030L5s43.15—
22:44:40autofocusNGC 2030L5s42.54—
22:44:55autofocusNGC 2030L5s42.06—
22:45:15autofocusNGC 2030L5s52.17—
22:45:35autofocusNGC 2030L5s42.62—
22:45:55autofocusNGC 2030L5s23.45—
22:46:15autofocusNGC 2030L5s34.41—
22:46:35autofocusNGC 2030L5s10.00—
22:46:55autofocusNGC 2030L5s42.10—
22:56:21lightNGC 2030H300s543.9820%
23:01:54lightNGC 2030H300s324.1212%
23:06:55lightNGC 2030H300s483.9618%
23:12:09lightNGC 2030H300s1313.7849%
23:17:21lightNGC 2030O300s1733.6064%
23:22:54lightNGC 2030O300s1853.5468%
23:27:55lightNGC 2030O300s1323.7849%
23:33:30lightNGC 2030O300s244.349%
23:38:41lightNGC 2030S300s1183.7844%
23:44:15lightNGC 2030S300s1973.7774%
23:49:16lightNGC 2030S300s1903.5271%
23:54:43lightNGC 2030S300s2583.6397%
00:00:56lightNGC 2030H300s2753.74102%
00:06:32lightNGC 2030H300s2693.69100%
00:11:33lightNGC 2030H300s2533.7294%
00:17:00lightNGC 2030H300s2723.80101%
00:17:30autofocusNGC 2030L5s2112.19—
00:17:44autofocusNGC 2030L5s526.50—
00:17:59autofocusNGC 2030L5s804.81—
00:18:14autofocusNGC 2030L5s1003.81—
00:18:29autofocusNGC 2030L5s1642.69—
00:18:49autofocusNGC 2030L5s2412.08—
00:19:09autofocusNGC 2030L5s2741.82—
00:19:29autofocusNGC 2030L5s2592.08—
00:19:49autofocusNGC 2030L5s1762.82—
00:20:04autofocusNGC 2030L5s1363.73—
00:20:19autofocusNGC 2030L5s814.74—
00:20:39autofocusNGC 2030L5s2651.92—
00:26:45lightNGC 2030O300s3423.25126%
00:32:14lightNGC 2030O300s3173.28117%
00:37:15lightNGC 2030O300s2823.24104%
00:42:45lightNGC 2030O300s1913.1870%
00:47:56lightNGC 2030S300s2673.36100%
00:53:32lightNGC 2030S300s2943.54110%
00:58:33lightNGC 2030S300s2463.4692%
01:04:10lightNGC 2030S300s303.2511%
01:10:19lightNGC 2030H300s903.2333%
01:15:46lightNGC 2030H300s3333.26124%
01:20:47lightNGC 2030H300s3003.52112%
01:26:19lightNGC 2030H300s3113.40116%
01:31:31lightNGC 2030O300s3153.36116%
01:37:01lightNGC 2030O300s2973.46109%
01:42:02lightNGC 2030O300s2723.57100%
01:42:39autofocusNGC 2030L5s2711.89—
01:42:54autofocusNGC 2030L5s705.78—
01:43:09autofocusNGC 2030L5s944.51—
01:43:24autofocusNGC 2030L5s1443.08—
01:43:39autofocusNGC 2030L5s2192.27—
01:43:59autofocusNGC 2030L5s2821.88—
01:44:19autofocusNGC 2030L5s2761.98—
01:44:39autofocusNGC 2030L5s1992.75—
01:44:54autofocusNGC 2030L5s1263.55—
01:45:09autofocusNGC 2030L5s1064.38—
01:45:29autofocusNGC 2030L5s2651.98—
01:51:34lightNGC 2030O300s3173.35117%
01:56:46lightNGC 2030S300s3283.45123%
02:02:16lightNGC 2030S300s3193.55119%
02:07:17lightNGC 2030S300s3593.35134%
02:12:46lightNGC 2030S300s3823.33143%
02:18:55lightNGC 2030H300s3333.51124%
02:24:37lightNGC 2030H300s2963.74110%
02:29:39lightNGC 2030H300s3193.66119%
02:35:18lightNGC 2030H300s3123.65116%
02:40:31lightNGC 2030O300s3003.61110%
02:46:01lightNGC 2030O300s2953.58108%
02:51:03lightNGC 2030O300s2573.7894%
02:51:49autofocusNGC 2030L5s2822.04—
02:52:04autofocusNGC 2030L5s626.02—
02:52:19autofocusNGC 2030L5s794.62—
02:52:34autofocusNGC 2030L5s1293.42—
02:52:49autofocusNGC 2030L5s2152.57—
02:53:09autofocusNGC 2030L5s2572.20—
02:53:29autofocusNGC 2030L5s2462.27—
02:53:49autofocusNGC 2030L5s2472.41—
02:54:09autofocusNGC 2030L5s1803.23—
02:54:24autofocusNGC 2030L5s1264.21—
02:54:44autofocusNGC 2030L5s3021.88—
03:00:50lightNGC 2030O300s2733.69100%
03:06:01lightNGC 2030S300s3233.68121%
03:11:30lightNGC 2030S300s3073.82115%
03:16:31lightNGC 2030S300s2943.70110%
03:21:58lightNGC 2030S300s2753.84103%
03:27:11lightNGC 2030H300s2313.9286%
03:32:36lightNGC 2030H300s1664.0262%
03:37:37lightNGC 2030H300s1244.0046%
03:43:17lightNGC 2030H300s774.2229%
03:48:31lightNGC 2030O300s254.429%
03:55:07lightNGC 2030O300s144.295%
04:00:09lightNGC 2030O300s44.781%
04:00:30centeringNGC 2030L5s52.32—
04:00:44centeringNGC 2030L5s25.19—
04:00:59centeringNGC 2030L5s24.08—
04:01:14centeringNGC 2030L5s33.45—
04:01:29centeringNGC 2030L5s42.57—
04:01:49centeringNGC 2030L5s42.48—
04:02:09centeringNGC 2030L5s42.51—
04:02:29centeringNGC 2030L5s42.70—
04:02:49centeringNGC 2030L5s33.22—
04:03:09centeringNGC 2030L5s23.86—
04:03:24centeringNGC 2030L5s10.00—
04:03:44centeringNGC 2030L5s00.00—
04:03:59centeringNGC 2030L5s00.00—
04:04:19centeringNGC 2030L5s00.00—
04:04:49centeringNGC 2030L5s00.00—
04:05:09centeringNGC 2030L5s00.00—
04:05:29centeringNGC 2030L5s00.00—
04:05:49centeringNGC 2030L5s00.00—
04:06:19centeringNGC 2030L5s00.00—
04:06:34centeringNGC 2030L5s10.00—
04:06:49centeringNGC 2030L5s10.00—
04:07:04centeringNGC 2030L5s22.67—
04:07:24centeringNGC 2030L5s22.39—
04:07:44centeringNGC 2030L5s22.39—
04:08:04centeringNGC 2030L5s22.45—
04:08:24centeringNGC 2030L5s00.00—
04:08:54centeringNGC 2030L5s00.00—
04:09:14centeringNGC 2030L5s00.00—
04:09:34centeringNGC 2030L5s00.00—
04:09:54centeringNGC 2030L5s00.00—
04:19:10lightNGC 2030O300s00.000%
04:19:40centeringNGC 2030L5s00.00—
04:19:54centeringNGC 2030L5s00.00—
04:20:09centeringNGC 2030L5s00.00—
04:20:24centeringNGC 2030L5s00.00—
04:20:39centeringNGC 2030L5s00.00—
04:21:09centeringNGC 2030L5s00.00—
04:21:24centeringNGC 2030L5s00.00—
04:21:44centeringNGC 2030L5s00.00—
04:21:59centeringNGC 2030L5s00.00—
04:28:46lightNGC 2030S300s00.000%
04:29:10centeringNGC 2030L5s00.00—
04:29:24centeringNGC 2030L5s00.00—
04:29:39centeringNGC 2030L5s00.00—
04:29:54centeringNGC 2030L5s00.00—
04:30:09centeringNGC 2030L5s00.00—
04:30:39centeringNGC 2030L5s00.00—
04:30:59centeringNGC 2030L5s00.00—
04:31:19centeringNGC 2030L5s00.00—
04:31:39centeringNGC 2030L5s00.00—
04:41:48lightNGC 2030S300s00.000%
04:42:10centeringNGC 2030L5s00.00—
04:42:24centeringNGC 2030L5s00.00—
04:42:39centeringNGC 2030L5s00.00—
04:42:54centeringNGC 2030L5s00.00—
04:43:09centeringNGC 2030L5s00.00—
04:43:39centeringNGC 2030L5s00.00—
04:43:59centeringNGC 2030L5s00.00—
04:44:19centeringNGC 2030L5s00.00—
04:44:39centeringNGC 2030L5s00.00—
04:51:02lightNGC 2030S300s00.000%
04:51:20centeringNGC 2030L5s00.00—
04:51:34centeringNGC 2030L5s00.00—
04:51:49centeringNGC 2030L5s00.00—
04:52:04centeringNGC 2030L5s00.00—
04:52:19centeringNGC 2030L5s00.00—
04:52:49centeringNGC 2030L5s00.00—
04:53:09centeringNGC 2030L5s00.00—
04:53:29centeringNGC 2030L5s00.00—
04:53:49centeringNGC 2030L5s00.00—

Star counts come from Hocus Focus detection on each saved sub, tagged with the filter in place at exposure start and the target then being imaged. Frames inside completed autofocus runs are excluded. Still capture times come from the AllSky filenames. All times are local.