Sky transparency — night of 6–7 October 2026

Cloud arrived at 22:38 — detected by the all-sky camera, independent of N.I.N.A. Before it the sky ran at index 100 (IQR 92–114); after it 98 (IQR 53–100). 19 of 46 light frames landed before the cloud. 44 of 44 failures are attributed to cloud. Guiding ran at 0.94″ RMS before the cloud and 2.73″ after; the worst minute was 13.26″ at 04:21. The 05:27 autofocus run fitted its curve on almost no stars and should not be trusted. Morning sky flats: 63 frames (O 21, S 21, H 21), 06:43–06:47, auto-exposure 0.9–1.2 s.

Index before 22:38

100 · IQR 92–114

Index after 22:38

98 · IQR 53–100

Cloud onset (all-sky)

22:38 · independent

Errors after onset

44 of 44 · solve + PHD2

Guide RMS

2.10″ · RA 1.15 · Dec 1.76

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

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.

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. 2538 guide frames over 4.7 h of guiding in 16 sessions; the gaps are slews, dither settles and autofocus runs, when PHD2 was not guiding. PHD2 discarded 268 further frames — usually a lost star. The worst minute (13.26″ at 04:21) is clamped at the top of the plot.

RA RMS Dec RMS ◆ PHD2 error

All‑sky frames at the key moments

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

All-sky at 20:29 — **20:29** · start of night

All-sky at 22:38 — **22:38** · cloud onset

All-sky at 22:51 — **22:51** · peak brightness 90.9

All-sky at 06:20 — **06:20** · end of night

Clear‑sky reference medians

The divisors behind the index — median detected stars per light sub before 22:38. IC 434 Panel 1 and IC 434 Panel 2 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.

Target	Filter	Median stars	Frames	Source
IC 434 Panel 1	H	169	4	whole night, cloud included
IC 434 Panel 1	O	178	4	whole night, cloud included
IC 434 Panel 1	S	312	4	whole night, cloud included
IC 434 Panel 2	H	152	4	whole night, cloud included
IC 434 Panel 2	O	0	4	whole night, cloud included
IC 434 Panel 2	S	406	4	whole night, cloud included
M 17	H	728	8	tonight, clear frames
M 17	O	1259	7	tonight, clear frames
M 17	S	1952	4	tonight, clear frames

Event timeline

All observatory events with their attributed causes.

22:53:35PHD2timed-out waiting for guider to settlecloud

03:14:04solve failedASTAP plate solve failedcloud

03:14:47solve failedASTAP plate solve failedcloud

04:06:14PHD2timed-out waiting for guider to settlecloud

04:14:14PHD2timed-out waiting for guider to settlecloud

04:19:18solve failedASTAP plate solve failedcloud

04:19:30solve failedASTAP plate solve failedcloud

04:21:28PHD2timed-out waiting for guider to settlecloud

04:26:31solve failedASTAP plate solve failedcloud

04:26:42solve failedASTAP plate solve failedcloud

04:28:30PHD2timed-out waiting for guider to settlecloud

04:33:34solve failedASTAP plate solve failedcloud

04:33:44solve failedASTAP plate solve failedcloud

04:36:11PHD2timed-out waiting for guider to settlecloud

04:41:14solve failedASTAP plate solve failedcloud

04:41:24solve failedASTAP plate solve failedcloud

04:43:15PHD2timed-out waiting for guider to settlecloud

04:46:00PHD2timed-out waiting for guider to settlecloud

04:51:04solve failedASTAP plate solve failedcloud

04:51:15solve failedASTAP plate solve failedcloud

04:53:17PHD2timed-out waiting for guider to settlecloud

04:56:47AF failedautofocus run started 04:53:17 did not completecloud

04:59:57PHD2timed-out waiting for guider to settlecloud

05:03:11solve failedASTAP plate solve failedcloud

05:03:23solve failedASTAP plate solve failedcloud

05:07:42AF failedautofocus run started 05:03:09 did not completecloud

05:29:59AF rejectednew focus point HFR 1.8886833776190814 significantly worse than originalcloud

05:33:38solve failedASTAP plate solve failedcloud

05:33:43solve failedASTAP plate solve failedcloud

05:35:48solve failedASTAP plate solve failedcloud

05:37:54solve failedASTAP plate solve failedcloud

05:40:00solve failedASTAP plate solve failedcloud

05:42:05solve failedASTAP plate solve failedcloud

05:42:06solve failedASTAP plate solve failedcloud

05:44:12solve failedASTAP plate solve failedcloud

05:46:18solve failedASTAP plate solve failedcloud

05:48:23solve failedASTAP plate solve failedcloud

05:48:24solve failedASTAP plate solve failedcloud

05:50:29solve failedASTAP plate solve failedcloud

05:50:30solve failedASTAP plate solve failedcloud

05:52:35solve failedASTAP plate solve failedcloud

05:52:36solve failedASTAP plate solve failedcloud

All 169 frames (excludes the 63 sky flats — no stars to detect)

Time	Class	Target	Filter	Exp	Stars	HFR	Index
20:29:26	autofocus	M 17	L	5s	498	2.90	—
20:29:44	autofocus	M 17	L	5s	539	2.47	—
20:29:59	autofocus	M 17	L	5s	908	1.71	—
20:30:14	autofocus	M 17	L	5s	946	1.52	—
20:30:29	autofocus	M 17	L	5s	859	1.92	—
20:30:49	autofocus	M 17	L	5s	513	2.75	—
20:31:09	autofocus	M 17	L	5s	264	3.97	—
20:31:29	autofocus	M 17	L	5s	177	5.02	—
20:31:49	autofocus	M 17	L	5s	327	4.12	—
20:32:04	autofocus	M 17	L	5s	217	5.47	—
20:32:24	autofocus	M 17	L	5s	1027	1.56	—
20:38:53	light	M 17	H	300s	683	2.62	94%
20:44:22	light	M 17	H	300s	622	2.79	85%
20:50:25	light	M 17	H	300s	616	2.83	85%
20:51:19	autofocus	M 17	L	5s	1187	1.46	—
20:51:38	autofocus	M 17	L	5s	209	6.01	—
20:51:53	autofocus	M 17	L	5s	403	3.98	—
20:52:08	autofocus	M 17	L	5s	464	3.27	—
20:52:23	autofocus	M 17	L	5s	740	2.06	—
20:52:43	autofocus	M 17	L	5s	1129	1.44	—
20:53:03	autofocus	M 17	L	5s	1065	1.64	—
20:53:23	autofocus	M 17	L	5s	876	2.03	—
20:53:38	autofocus	M 17	L	5s	425	3.25	—
20:53:58	autofocus	M 17	L	5s	231	4.54	—
20:54:18	autofocus	M 17	L	5s	1164	1.52	—
21:00:16	light	M 17	H	300s	856	2.27	118%
21:06:03	light	M 17	O	300s	1441	2.38	114%
21:11:57	light	M 17	O	300s	1361	2.48	108%
21:17:28	light	M 17	O	300s	1281	2.56	102%
21:22:59	light	M 17	O	300s	1254	2.61	100%
21:28:51	light	M 17	S	300s	1952	2.51	100%
21:34:40	light	M 17	S	300s	1793	2.69	92%
21:40:18	light	M 17	S	300s	1529	2.96	78%
21:41:04	autofocus	M 17	L	5s	929	1.76	—
21:41:23	autofocus	M 17	L	5s	181	6.50	—
21:41:38	autofocus	M 17	L	5s	254	4.72	—
21:41:53	autofocus	M 17	L	5s	360	3.53	—
21:42:08	autofocus	M 17	L	5s	510	2.73	—
21:42:28	autofocus	M 17	L	5s	926	1.74	—
21:42:48	autofocus	M 17	L	5s	1051	1.48	—
21:43:08	autofocus	M 17	L	5s	930	1.80	—
21:43:28	autofocus	M 17	L	5s	500	2.76	—
21:43:43	autofocus	M 17	L	5s	295	3.82	—
21:43:58	autofocus	M 17	L	5s	202	4.94	—
21:44:18	autofocus	M 17	L	5s	1059	1.48	—
21:50:11	light	M 17	S	300s	2285	2.18	117%
21:56:08	light	M 17	H	300s	838	2.29	115%
22:01:45	light	M 17	H	300s	686	2.65	94%
22:07:11	light	M 17	H	300s	728	2.52	100%
22:08:08	autofocus	M 17	L	5s	910	1.66	—
22:08:23	autofocus	M 17	L	5s	177	6.01	—
22:08:38	autofocus	M 17	L	5s	250	4.32	—
22:08:53	autofocus	M 17	L	5s	337	3.34	—
22:09:08	autofocus	M 17	L	5s	713	1.96	—
22:09:28	autofocus	M 17	L	5s	931	1.56	—
22:09:48	autofocus	M 17	L	5s	923	1.63	—
22:10:08	autofocus	M 17	L	5s	614	2.26	—
22:10:28	autofocus	M 17	L	5s	312	3.41	—
22:10:43	autofocus	M 17	L	5s	182	4.57	—
22:11:03	autofocus	M 17	L	5s	965	1.47	—
22:17:00	light	M 17	H	300s	829	2.33	114%
22:22:46	light	M 17	O	300s	1259	2.49	100%
22:28:17	light	M 17	O	300s	1194	2.54	95%
22:33:48	light	M 17	O	300s	1121	2.65	89%
22:39:40	light	M 17	O	300s	1074	2.65	85%
22:45:21	light	M 17	S	300s	958	2.78	49%
22:51:31	light	M 17	S	300s	251	2.90	13%
02:31:24	autofocus	IC 434 Panel 1	L	5s	120	1.74	—
02:31:38	autofocus	IC 434 Panel 1	L	5s	47	5.36	—
02:31:53	autofocus	IC 434 Panel 1	L	5s	64	4.00	—
02:32:09	autofocus	IC 434 Panel 1	L	5s	68	3.23	—
02:32:23	autofocus	IC 434 Panel 1	L	5s	109	2.08	—
02:32:43	autofocus	IC 434 Panel 1	L	5s	152	1.98	—
02:33:03	autofocus	IC 434 Panel 1	L	5s	131	2.20	—
02:33:23	autofocus	IC 434 Panel 1	L	5s	85	3.17	—
02:33:38	autofocus	IC 434 Panel 1	L	5s	66	4.25	—
02:33:53	autofocus	IC 434 Panel 1	L	5s	55	5.22	—
02:34:13	autofocus	IC 434 Panel 1	L	5s	164	1.91	—
02:41:38	light	IC 434 Panel 1	H	300s	166	2.90	98%
02:47:29	light	IC 434 Panel 1	H	300s	169	2.81	100%
02:52:59	light	IC 434 Panel 1	H	300s	152	3.12	90%
02:53:59	autofocus	IC 434 Panel 1	L	5s	135	1.60	—
02:54:13	autofocus	IC 434 Panel 1	L	5s	42	5.39	—
02:54:28	autofocus	IC 434 Panel 1	L	5s	64	4.04	—
02:54:43	autofocus	IC 434 Panel 1	L	5s	80	2.92	—
02:54:58	autofocus	IC 434 Panel 1	L	5s	113	2.00	—
02:55:18	autofocus	IC 434 Panel 1	L	5s	138	1.66	—
02:55:38	autofocus	IC 434 Panel 1	L	5s	126	1.91	—
02:55:58	autofocus	IC 434 Panel 1	L	5s	98	2.64	—
02:56:13	autofocus	IC 434 Panel 1	L	5s	67	3.77	—
02:56:28	autofocus	IC 434 Panel 1	L	5s	45	5.07	—
02:56:48	autofocus	IC 434 Panel 1	L	5s	136	1.67	—
03:02:45	light	IC 434 Panel 1	H	300s	189	2.50	112%
03:08:27	light	IC 434 Panel 1	O	300s	173	2.44	97%
03:13:59	light	IC 434 Panel 1	O	300s	165	2.53	93%
03:19:31	light	IC 434 Panel 1	O	300s	184	2.35	103%
03:25:13	light	IC 434 Panel 1	O	300s	178	2.37	100%
03:31:08	light	IC 434 Panel 1	S	300s	312	2.17	100%
03:36:38	light	IC 434 Panel 1	S	300s	307	2.15	98%
03:42:14	light	IC 434 Panel 1	S	300s	304	2.26	97%
03:47:42	light	IC 434 Panel 1	S	300s	315	2.18	101%
03:48:29	autofocus	IC 434 Panel 2	L	5s	200	1.40	—
03:48:43	autofocus	IC 434 Panel 2	L	5s	69	5.32	—
03:48:58	autofocus	IC 434 Panel 2	L	5s	89	3.88	—
03:49:13	autofocus	IC 434 Panel 2	L	5s	118	2.75	—
03:49:28	autofocus	IC 434 Panel 2	L	5s	238	1.52	—
03:49:48	autofocus	IC 434 Panel 2	L	5s	199	1.38	—
03:50:08	autofocus	IC 434 Panel 2	L	5s	216	1.76	—
03:50:28	autofocus	IC 434 Panel 2	L	5s	134	2.76	—
03:50:43	autofocus	IC 434 Panel 2	L	5s	86	3.89	—
03:50:58	autofocus	IC 434 Panel 2	L	5s	54	5.12	—
03:51:18	autofocus	IC 434 Panel 2	L	5s	209	1.38	—
03:58:44	light	IC 434 Panel 2	H	300s	243	2.10	160%
04:04:15	light	IC 434 Panel 2	H	300s	152	2.26	100%
04:12:10	light	IC 434 Panel 2	H	300s	0	0.00	0%
04:19:17	light	IC 434 Panel 2	H	300s	1	0.00	1%
04:26:30	light	IC 434 Panel 2	O	300s	0	0.00	—
04:33:33	light	IC 434 Panel 2	O	300s	0	0.00	—
04:41:13	light	IC 434 Panel 2	O	300s	0	0.00	—
04:51:03	light	IC 434 Panel 2	O	300s	0	0.00	—
04:53:39	centering	IC 434 Panel 2	L	5s	0	0.00	—
04:53:53	centering	IC 434 Panel 2	L	5s	0	0.00	—
04:54:08	centering	IC 434 Panel 2	L	5s	0	0.00	—
04:54:23	centering	IC 434 Panel 2	L	5s	0	0.00	—
04:54:38	centering	IC 434 Panel 2	L	5s	10	2.38	—
04:54:58	centering	IC 434 Panel 2	L	5s	1	0.00	—
04:55:23	centering	IC 434 Panel 2	L	5s	0	0.00	—
04:55:43	centering	IC 434 Panel 2	L	5s	0	0.00	—
04:56:03	centering	IC 434 Panel 2	L	5s	0	0.00	—
04:56:23	centering	IC 434 Panel 2	L	5s	0	0.00	—
05:03:10	light	IC 434 Panel 2	S	300s	1	0.00	0%
05:03:29	centering	IC 434 Panel 2	L	5s	1	0.00	—
05:03:44	centering	IC 434 Panel 2	L	5s	0	0.00	—
05:03:59	centering	IC 434 Panel 2	L	5s	0	0.00	—
05:04:14	centering	IC 434 Panel 2	L	5s	9	3.40	—
05:04:28	centering	IC 434 Panel 2	L	5s	4	2.04	—
05:04:49	centering	IC 434 Panel 2	L	5s	9	1.62	—
05:05:09	centering	IC 434 Panel 2	L	5s	8	1.71	—
05:05:28	centering	IC 434 Panel 2	L	5s	9	2.46	—
05:05:48	centering	IC 434 Panel 2	L	5s	6	3.58	—
05:06:08	centering	IC 434 Panel 2	L	5s	5	4.78	—
05:06:29	centering	IC 434 Panel 2	L	5s	5	5.88	—
05:06:48	centering	IC 434 Panel 2	L	5s	5	6.85	—
05:07:03	centering	IC 434 Panel 2	L	5s	11	8.14	—
05:07:24	centering	IC 434 Panel 2	L	5s	31	1.56	—
05:13:45	light	IC 434 Panel 2	S	300s	217	2.37	53%
05:21:00	light	IC 434 Panel 2	S	300s	414	2.13	102%
05:26:34	light	IC 434 Panel 2	S	300s	406	2.26	100%
05:27:19	autofocus	IC 434 Panel 3	L	5s	261	1.50	—
05:27:34	autofocus	IC 434 Panel 3	L	5s	71	5.38	—
05:27:49	autofocus	IC 434 Panel 3	L	5s	98	3.92	—
05:28:04	autofocus	IC 434 Panel 3	L	5s	66	2.89	—
05:28:18	autofocus	IC 434 Panel 3	L	5s	33	2.02	—
05:28:34	autofocus	IC 434 Panel 3	L	5s	34	1.68	—
05:28:53	autofocus	IC 434 Panel 3	L	5s	14	2.15	—
05:29:09	autofocus	IC 434 Panel 3	L	5s	29	2.85	—
05:29:24	autofocus	IC 434 Panel 3	L	5s	4	4.03	—
05:29:39	autofocus	IC 434 Panel 3	L	5s	2	5.13	—
05:29:59	autofocus	IC 434 Panel 3	L	5s	9	1.89	—
05:30:24	autofocus	IC 434 Panel 3	L	5s	2	5.55	—
05:30:39	autofocus	IC 434 Panel 3	L	5s	8	4.13	—
05:30:54	autofocus	IC 434 Panel 3	L	5s	10	3.11	—
05:31:09	autofocus	IC 434 Panel 3	L	5s	7	2.34	—
05:31:29	autofocus	IC 434 Panel 3	L	5s	7	1.91	—
05:31:49	autofocus	IC 434 Panel 3	L	5s	4	2.16	—
05:32:09	autofocus	IC 434 Panel 3	L	5s	4	2.84	—
05:32:24	autofocus	IC 434 Panel 3	L	5s	4	3.75	—
05:32:39	autofocus	IC 434 Panel 3	L	5s	3	5.09	—
05:32:59	autofocus	IC 434 Panel 3	L	5s	7	1.70	—

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.