Sky transparency — night of 10–11 September 2026

Cloud arrived at 21:14 — detected by the all-sky camera, independent of N.I.N.A. Before it the sky ran at index 89 (IQR 87–92); after it 90 (IQR 15–116). 2 of 68 light frames landed before the cloud. 33 of 33 failures are attributed to cloud. Guiding ran at 0.82″ RMS before the cloud and 0.76″ after; the worst minute was 1.95″ at 05:18. The 01:32 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), 06:18–06:23, auto-exposure 2.2–5.0 s.

Index before 21:14
89 · IQR 87–92
Index after 21:14
90 · IQR 15–116
Cloud onset (all-sky)
21:14 · independent
Errors after onset
33 of 33 · solve + PHD2
Guide RMS
0.77″ · RA 0.50 · Dec 0.58

Normalised transparency index, by filter

100 = that target and filter's own clear‑sky median (rolling median over recent clear nights). 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
05010015020021:0022:0023:0000:0001:0002:0003:0004:0005:0006:00% of clear-sky medianclear-sky baselineIC 4628→ IC 4628→ NGC 2070OHS

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.

025507510021:0022:0023:0000:0001:0002:0003:0004:0005:0006:00Mean 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. 1264 guide frames over 3.6 h of guiding in 11 sessions; the gaps are slews, dither settles and autofocus runs, when PHD2 was not guiding. PHD2 discarded 742 further frames — usually a lost star. The worst minute (1.95″ at 05:18) is clamped at the top of the plot.

RA RMS Dec RMS ◆ PHD2 error
0.00.30.60.91.221:0022:0023:0000:0001:0002:0003:0004:0005:0006:00RMS guide error (arcsec)night RMS 0.77″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 20:23
20:23 · start of night
All-sky at 21:14
21:14 · cloud onset
All-sky at 21:18
21:18 · peak brightness 98.3
All-sky at 06:01
06:01 · end of night

Clear‑sky reference medians

The divisors behind the index — median detected stars per light sub before 21:14.

TargetFilterMedian starsFramesSource
IC 4628H33259earlier clear nights
IC 4628O73551earlier clear nights
IC 4628S87739earlier clear nights
NGC 2070H31035earlier clear nights
NGC 2070O22836earlier clear nights
NGC 2070S87930earlier clear nights

Event timeline

All observatory events with their attributed causes.

PHD2Guiding stoppedcloud
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
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
solve failedASTAP plate solve failedcloud
solve failedASTAP plate solve failedcloud
solve failedASTAP plate solve failedcloud
solve failedASTAP plate solve failedcloud
AF failedautofocus run started 01:12:36 did not completecloud
PHD2timed-out waiting for guider to settlecloud
solve failedASTAP plate solve failedcloud
solve failedASTAP plate solve failedcloud
AF failedautofocus run started 01:22:07 did not completecloud
PHD2failed to find a suitable guide starcloud
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
PHD2Guiding stoppedcloud
PHD2timed-out waiting for guider to settlecloud
PHD2timed-out waiting for guider to settlecloud
PHD2timed-out waiting for guider to settlecloud
PHD2timed-out waiting for guider to settlecloud
PHD2timed-out waiting for guider to settlecloud
All 213 frames (excludes the 60 sky flats — no stars to detect)
TimeClassTargetFilterExpStarsHFRIndex
20:23:37autofocusIC 4628L5s3734.18—
20:23:56autofocusIC 4628L5s6362.44—
20:24:10autofocusIC 4628L5s9891.73—
20:24:26autofocusIC 4628L5s7812.23—
20:24:45autofocusIC 4628L5s6192.91—
20:25:06autofocusIC 4628L5s4764.10—
20:25:26autofocusIC 4628L5s3964.78—
20:25:46autofocusIC 4628L5s3973.69—
20:26:01autofocusIC 4628L5s3174.62—
20:26:16autofocusIC 4628L5s2445.65—
20:26:36autofocusIC 4628L5s8781.95—
20:33:31lightIC 4628H300s3053.7592%
20:39:04lightIC 4628H300s2883.9287%
20:39:40autofocusIC 4628L5s6812.17—
20:39:55autofocusIC 4628L5s2046.44—
20:40:10autofocusIC 4628L5s2564.82—
20:40:25autofocusIC 4628L5s3573.81—
20:40:40autofocusIC 4628L5s4672.82—
20:41:00autofocusIC 4628L5s5742.33—
20:41:20autofocusIC 4628L5s8171.95—
20:41:40autofocusIC 4628L5s7272.36—
20:42:00autofocusIC 4628L5s5013.23—
20:42:15autofocusIC 4628L5s4094.15—
20:42:30autofocusIC 4628L5s3534.83—
20:42:50autofocusIC 4628L5s7891.95—
22:14:47autofocusIC 4628L5s5402.36—
22:15:02autofocusIC 4628L5s1736.96—
22:15:16autofocusIC 4628L5s2505.30—
22:15:31autofocusIC 4628L5s2994.41—
22:15:46autofocusIC 4628L5s4133.21—
22:16:06autofocusIC 4628L5s5722.17—
22:16:26autofocusIC 4628L5s7611.74—
22:16:46autofocusIC 4628L5s6812.03—
22:17:06autofocusIC 4628L5s5142.59—
22:17:21autofocusIC 4628L5s4133.53—
22:17:36autofocusIC 4628L5s3144.35—
22:17:56autofocusIC 4628L5s6641.90—
22:24:23lightIC 4628H300s3993.21120%
22:29:37lightIC 4628H300s3633.38109%
22:35:03lightIC 4628H300s3473.45105%
22:40:28lightIC 4628H300s3683.31111%
22:46:11lightIC 4628O300s7043.5096%
22:51:43lightIC 4628O300s7193.3898%
22:57:10lightIC 4628O300s6783.4792%
23:02:35lightIC 4628O300s6463.5588%
23:08:41lightIC 4628S300s8723.4799%
23:14:08lightIC 4628S300s7933.6690%
23:19:33lightIC 4628S300s7533.6886%
23:40:06autofocusNGC 2070L5s4511.89—
23:40:21autofocusNGC 2070L5s1135.59—
23:40:36autofocusNGC 2070L5s1284.51—
23:40:51autofocusNGC 2070L5s2472.94—
23:41:06autofocusNGC 2070L5s3832.14—
23:41:26autofocusNGC 2070L5s4751.81—
23:41:46autofocusNGC 2070L5s4442.00—
23:42:06autofocusNGC 2070L5s2932.71—
23:42:21autofocusNGC 2070L5s2333.37—
23:42:36autofocusNGC 2070L5s1714.50—
23:42:56autofocusNGC 2070L5s4881.83—
23:50:03lightNGC 2070H300s4163.13134%
23:55:30lightNGC 2070H300s3883.19125%
00:01:16lightNGC 2070H300s3573.18115%
00:06:41lightNGC 2070H300s3053.2098%
00:11:53lightNGC 2070O300s673.2429%
00:16:54lightNGC 2070O300s353.3915%
00:21:55lightNGC 2070O300s1193.4352%
00:26:56lightNGC 2070O300s453.3520%
00:32:08lightNGC 2070S300s233.223%
00:37:09lightNGC 2070S300s43.400%
00:42:11lightNGC 2070S300s00.000%
00:47:12lightNGC 2070S300s00.000%
00:52:23lightNGC 2070H300s00.000%
00:57:24lightNGC 2070H300s00.000%
01:02:25lightNGC 2070H300s00.000%
01:07:26lightNGC 2070H300s23.731%
01:12:38lightNGC 2070O300s00.000%
01:13:01centeringNGC 2070L5s00.00—
01:13:16centeringNGC 2070L5s00.00—
01:13:31centeringNGC 2070L5s00.00—
01:13:46centeringNGC 2070L5s00.00—
01:14:01centeringNGC 2070L5s00.00—
01:14:26centeringNGC 2070L5s00.00—
01:14:41centeringNGC 2070L5s00.00—
01:15:01centeringNGC 2070L5s00.00—
01:15:21centeringNGC 2070L5s00.00—
01:22:08lightNGC 2070O300s00.000%
01:22:21centeringNGC 2070L5s10.00—
01:22:36centeringNGC 2070L5s00.00—
01:22:51centeringNGC 2070L5s55.86—
01:23:06centeringNGC 2070L5s154.40—
01:23:21centeringNGC 2070L5s93.60—
01:23:41centeringNGC 2070L5s10.00—
01:24:01centeringNGC 2070L5s42.00—
01:24:21centeringNGC 2070L5s362.01—
01:24:41centeringNGC 2070L5s302.40—
01:25:01centeringNGC 2070L5s23.28—
01:25:21centeringNGC 2070L5s34.19—
01:25:41centeringNGC 2070L5s25.24—
01:26:01centeringNGC 2070L5s168.10—
01:26:21centeringNGC 2070L5s521.75—
01:32:08autofocusNGC 2070O300s764.41—
01:32:26autofocusNGC 2070L5s492.64—
01:32:41autofocusNGC 2070L5s517.34—
01:32:56autofocusNGC 2070L5s825.76—
01:33:11autofocusNGC 2070L5s724.58—
01:33:26autofocusNGC 2070L5s333.56—
01:33:46autofocusNGC 2070L5s22.27—
01:34:06autofocusNGC 2070L5s51.95—
01:34:26autofocusNGC 2070L5s81.87—
01:34:46autofocusNGC 2070L5s00.00—
01:35:06autofocusNGC 2070L5s43.09—
01:35:26autofocusNGC 2070L5s44.25—
01:35:41autofocusNGC 2070L5s55.49—
01:35:56autofocusNGC 2070L5s76.44—
01:36:16autofocusNGC 2070L5s171.98—
01:42:28lightNGC 2070O300s10.000%
01:47:38lightNGC 2070S300s43.590%
01:52:39lightNGC 2070S300s10.000%
01:57:40lightNGC 2070S300s00.000%
02:02:41lightNGC 2070S300s1173.2713%
02:07:53lightNGC 2070H300s743.4124%
02:12:54lightNGC 2070H300s463.2115%
02:17:55lightNGC 2070H300s1363.4844%
02:22:56lightNGC 2070H300s753.3624%
02:28:08lightNGC 2070O300s2173.1195%
02:33:09lightNGC 2070O300s903.2839%
02:38:10lightNGC 2070O300s333.2714%
02:43:12lightNGC 2070O300s1733.1476%
02:48:23lightNGC 2070S300s2873.1033%
02:53:24lightNGC 2070S300s6893.2178%
02:58:25lightNGC 2070S300s5233.1759%
03:03:27lightNGC 2070S300s4002.9946%
03:08:38autofocusNGC 2070H300s1883.17—
03:08:57autofocusNGC 2070L5s2321.94—
03:09:12autofocusNGC 2070L5s355.22—
03:09:27autofocusNGC 2070L5s143.79—
03:09:41autofocusNGC 2070L5s242.59—
03:09:57autofocusNGC 2070L5s862.11—
03:10:17autofocusNGC 2070L5s2852.10—
03:10:37autofocusNGC 2070L5s552.18—
03:10:56autofocusNGC 2070L5s403.01—
03:11:17autofocusNGC 2070L5s484.06—
03:11:36autofocusNGC 2070L5s334.82—
03:11:57autofocusNGC 2070L5s486.20—
03:12:16autofocusNGC 2070L5s396.55—
03:12:37autofocusNGC 2070L5s1161.95—
03:17:54lightNGC 2070H300s3773.08122%
03:22:55lightNGC 2070H300s4253.17137%
03:27:56lightNGC 2070H300s4373.13141%
03:33:09lightNGC 2070O300s4533.23199%
03:38:10autofocusNGC 2070O300s5013.09—
03:38:27autofocusNGC 2070L5s7331.68—
03:38:42autofocusNGC 2070L5s1715.61—
03:38:57autofocusNGC 2070L5s2114.27—
03:39:12autofocusNGC 2070L5s3303.13—
03:39:27autofocusNGC 2070L5s6082.03—
03:39:47autofocusNGC 2070L5s7031.72—
03:40:07autofocusNGC 2070L5s6232.04—
03:40:27autofocusNGC 2070L5s4532.62—
03:40:42autofocusNGC 2070L5s3023.63—
03:40:57autofocusNGC 2070L5s2344.55—
03:41:17autofocusNGC 2070L5s6611.85—
03:46:29lightNGC 2070O300s4293.29188%
03:51:30lightNGC 2070O300s4043.39177%
03:56:43lightNGC 2070S300s8233.2994%
04:01:45lightNGC 2070S300s9093.13103%
04:06:46autofocusNGC 2070S300s8283.27—
04:07:02autofocusNGC 2070L5s7281.77—
04:07:17autofocusNGC 2070L5s1645.67—
04:07:32autofocusNGC 2070L5s2284.21—
04:07:47autofocusNGC 2070L5s3523.01—
04:08:02autofocusNGC 2070L5s6102.05—
04:08:22autofocusNGC 2070L5s7291.74—
04:08:42autofocusNGC 2070L5s5992.06—
04:09:02autofocusNGC 2070L5s4582.66—
04:09:17autofocusNGC 2070L5s3183.80—
04:09:32autofocusNGC 2070L5s2374.62—
04:09:52autofocusNGC 2070L5s7361.79—
04:15:04lightNGC 2070S300s8653.2498%
04:20:13lightNGC 2070H300s4663.05150%
04:25:15lightNGC 2070H300s4203.23135%
04:30:16autofocusNGC 2070H300s5082.95—
04:30:32autofocusNGC 2070L5s6721.92—
04:30:47autofocusNGC 2070L5s1565.72—
04:31:02autofocusNGC 2070L5s2454.32—
04:31:17autofocusNGC 2070L5s3573.13—
04:31:32autofocusNGC 2070L5s5842.19—
04:31:52autofocusNGC 2070L5s7351.78—
04:32:12autofocusNGC 2070L5s6422.07—
04:32:32autofocusNGC 2070L5s4952.55—
04:32:47autofocusNGC 2070L5s3123.62—
04:33:02autofocusNGC 2070L5s2244.78—
04:33:22autofocusNGC 2070L5s7051.85—
04:38:39lightNGC 2070H300s4383.14141%
04:43:53lightNGC 2070O300s4463.21196%
04:48:55lightNGC 2070O300s4013.36176%
04:55:03lightNGC 2070O300s4663.17204%
05:01:13lightNGC 2070O300s4883.12214%
05:02:47autofocusNGC 2070L5s7231.74—
05:03:07autofocusNGC 2070L5s1885.42—
05:03:22autofocusNGC 2070L5s2534.04—
05:03:37autofocusNGC 2070L5s3693.06—
05:03:52autofocusNGC 2070L5s6162.07—
05:04:12autofocusNGC 2070L5s7231.85—
05:04:32autofocusNGC 2070L5s5892.13—
05:04:52autofocusNGC 2070L5s4142.78—
05:05:07autofocusNGC 2070L5s3073.78—
05:05:27autofocusNGC 2070L5s2214.76—
05:05:47autofocusNGC 2070L5s7031.83—
05:11:59lightNGC 2070S300s9053.10103%
05:18:04lightNGC 2070S300s9033.03103%
05:23:40lightNGC 2070S300s8862.96101%
05:29:13lightNGC 2070S300s7842.9089%

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.