Sky transparency — night of 11–12 September 2026
No cloud onset detected. The transparency index held at 100 (IQR 91–104) across 81 light frames. Guiding held at 0.76″ RMS (RA 0.60″, Dec 0.47″) over 7.6 h; the worst minute was 3.89″ at 21:08. Morning sky flats: 60 frames (H 20, O 20, S 20), 06:16–06:21, auto-exposure 2.2–4.4 s.
Transparency index
100 · IQR 91–104
Light frames
81
Autofocus runs
8
Failures
0 · solve + PHD2
Guide RMS
0.76″ · RA 0.60 · Dec 0.47
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. 2440 guide frames over 7.6 h of guiding in 15 sessions; the gaps are slews, dither settles and autofocus runs, when PHD2 was not guiding. PHD2 discarded 20 further frames — usually a lost star. The worst minute (3.89″ at 21:08) 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.
Clear‑sky reference medians
The divisors behind the index — median detected stars per light sub.
| Target | Filter | Median stars | Frames | Source |
|---|---|---|---|---|
| IC 4628 | H | 299 | 8 | tonight, clear frames |
| IC 4628 | O | 766 | 8 | tonight, clear frames |
| IC 4628 | S | 877 | 6 | tonight, clear frames |
| NGC 2070 | H | 453 | 19 | tonight, clear frames |
| NGC 2070 | O | 490 | 20 | tonight, clear frames |
| NGC 2070 | S | 879 | 20 | tonight, clear frames |
Event timeline
All observatory events with their attributed causes.
All 172 frames (excludes the 60 sky flats — no stars to detect)
| Time | Class | Target | Filter | Exp | Stars | HFR | Index |
|---|---|---|---|---|---|---|---|
| 20:57:26 | autofocus | IC 4628 | L | 5s | 521 | 3.08 | — |
| 20:57:40 | autofocus | IC 4628 | L | 5s | 431 | 3.20 | — |
| 20:57:55 | autofocus | IC 4628 | L | 5s | 566 | 2.53 | — |
| 20:58:10 | autofocus | IC 4628 | L | 5s | 675 | 2.28 | — |
| 20:58:25 | autofocus | IC 4628 | L | 5s | 654 | 2.47 | — |
| 20:58:45 | autofocus | IC 4628 | L | 5s | 502 | 3.16 | — |
| 20:59:05 | autofocus | IC 4628 | L | 5s | 347 | 4.25 | — |
| 20:59:25 | autofocus | IC 4628 | L | 5s | 254 | 5.21 | — |
| 20:59:45 | autofocus | IC 4628 | L | 5s | 277 | 4.47 | — |
| 21:00:00 | autofocus | IC 4628 | L | 5s | 232 | 5.36 | — |
| 21:00:20 | autofocus | IC 4628 | L | 5s | 683 | 2.27 | — |
| 21:07:11 | light | IC 4628 | H | 300s | 226 | 4.43 | 76% |
| 21:12:13 | light | IC 4628 | H | 300s | 272 | 4.10 | 91% |
| 21:13:05 | autofocus | IC 4628 | L | 5s | 689 | 2.25 | — |
| 21:13:20 | autofocus | IC 4628 | L | 5s | 217 | 5.29 | — |
| 21:13:35 | autofocus | IC 4628 | L | 5s | 321 | 3.91 | — |
| 21:13:50 | autofocus | IC 4628 | L | 5s | 404 | 3.24 | — |
| 21:14:05 | autofocus | IC 4628 | L | 5s | 526 | 2.55 | — |
| 21:14:25 | autofocus | IC 4628 | L | 5s | 713 | 2.19 | — |
| 21:14:45 | autofocus | IC 4628 | L | 5s | 712 | 2.33 | — |
| 21:15:05 | autofocus | IC 4628 | L | 5s | 573 | 2.98 | — |
| 21:15:20 | autofocus | IC 4628 | L | 5s | 442 | 3.81 | — |
| 21:15:35 | autofocus | IC 4628 | L | 5s | 339 | 4.69 | — |
| 21:15:55 | autofocus | IC 4628 | L | 5s | 629 | 2.37 | — |
| 21:22:07 | light | IC 4628 | H | 300s | 287 | 3.83 | 96% |
| 21:27:08 | light | IC 4628 | H | 300s | 309 | 3.73 | 103% |
| 21:28:15 | autofocus | IC 4628 | L | 5s | 730 | 2.12 | — |
| 21:28:30 | autofocus | IC 4628 | L | 5s | 254 | 4.95 | — |
| 21:28:50 | autofocus | IC 4628 | L | 5s | 337 | 3.80 | — |
| 21:29:05 | autofocus | IC 4628 | L | 5s | 454 | 2.95 | — |
| 21:29:20 | autofocus | IC 4628 | L | 5s | 604 | 2.32 | — |
| 21:29:40 | autofocus | IC 4628 | L | 5s | 699 | 2.14 | — |
| 21:30:00 | autofocus | IC 4628 | L | 5s | 706 | 2.28 | — |
| 21:30:20 | autofocus | IC 4628 | L | 5s | 554 | 3.09 | — |
| 21:30:35 | autofocus | IC 4628 | L | 5s | 461 | 3.82 | — |
| 21:30:50 | autofocus | IC 4628 | L | 5s | 371 | 4.96 | — |
| 21:31:10 | autofocus | IC 4628 | L | 5s | 701 | 2.14 | — |
| 21:37:15 | light | IC 4628 | O | 300s | 815 | 3.76 | 106% |
| 21:42:18 | light | IC 4628 | O | 300s | 803 | 3.71 | 105% |
| 21:47:33 | light | IC 4628 | O | 300s | 766 | 3.81 | 100% |
| 21:52:35 | light | IC 4628 | O | 300s | 769 | 3.75 | 100% |
| 21:58:53 | light | IC 4628 | S | 300s | 930 | 3.73 | 106% |
| 22:03:54 | light | IC 4628 | S | 300s | 933 | 3.69 | 106% |
| 22:09:29 | light | IC 4628 | S | 300s | 877 | 3.85 | 100% |
| 22:14:31 | light | IC 4628 | S | 300s | 845 | 3.99 | 96% |
| 22:16:30 | autofocus | IC 4628 | L | 5s | 596 | 2.20 | — |
| 22:16:50 | autofocus | IC 4628 | L | 5s | 208 | 6.15 | — |
| 22:17:10 | autofocus | IC 4628 | L | 5s | 287 | 4.60 | — |
| 22:17:30 | autofocus | IC 4628 | L | 5s | 365 | 3.39 | — |
| 22:17:45 | autofocus | IC 4628 | L | 5s | 466 | 2.64 | — |
| 22:18:05 | autofocus | IC 4628 | L | 5s | 577 | 2.18 | — |
| 22:18:25 | autofocus | IC 4628 | L | 5s | 619 | 2.28 | — |
| 22:18:45 | autofocus | IC 4628 | L | 5s | 615 | 2.49 | — |
| 22:19:05 | autofocus | IC 4628 | L | 5s | 505 | 3.14 | — |
| 22:19:20 | autofocus | IC 4628 | L | 5s | 404 | 4.12 | — |
| 22:19:40 | autofocus | IC 4628 | L | 5s | 599 | 2.19 | — |
| 22:25:51 | light | IC 4628 | H | 300s | 282 | 3.98 | 94% |
| 22:30:52 | light | IC 4628 | H | 300s | 299 | 3.81 | 100% |
| 22:36:29 | light | IC 4628 | H | 300s | 310 | 3.77 | 104% |
| 22:41:30 | light | IC 4628 | H | 300s | 311 | 3.81 | 104% |
| 22:47:37 | light | IC 4628 | O | 300s | 606 | 4.09 | 79% |
| 22:52:38 | light | IC 4628 | O | 300s | 560 | 4.25 | 73% |
| 22:58:16 | light | IC 4628 | O | 300s | 578 | 4.18 | 75% |
| 23:03:17 | light | IC 4628 | O | 300s | 585 | 4.13 | 76% |
| 23:09:10 | light | IC 4628 | S | 300s | 701 | 4.33 | 80% |
| 23:14:11 | light | IC 4628 | S | 300s | 653 | 4.50 | 74% |
| 23:36:10 | autofocus | NGC 2070 | L | 5s | 485 | 2.00 | — |
| 23:36:30 | autofocus | NGC 2070 | L | 5s | 115 | 5.52 | — |
| 23:36:50 | autofocus | NGC 2070 | L | 5s | 154 | 4.28 | — |
| 23:37:05 | autofocus | NGC 2070 | L | 5s | 211 | 3.47 | — |
| 23:37:25 | autofocus | NGC 2070 | L | 5s | 345 | 2.55 | — |
| 23:37:45 | autofocus | NGC 2070 | L | 5s | 439 | 2.13 | — |
| 23:38:05 | autofocus | NGC 2070 | L | 5s | 459 | 2.12 | — |
| 23:38:25 | autofocus | NGC 2070 | L | 5s | 369 | 2.54 | — |
| 23:38:45 | autofocus | NGC 2070 | L | 5s | 271 | 3.43 | — |
| 23:39:05 | autofocus | NGC 2070 | L | 5s | 190 | 4.51 | — |
| 23:39:20 | autofocus | NGC 2070 | L | 5s | 120 | 5.58 | — |
| 23:39:40 | autofocus | NGC 2070 | L | 5s | 518 | 1.98 | — |
| 23:47:10 | light | NGC 2070 | H | 300s | 445 | 3.15 | 98% |
| 23:52:11 | light | NGC 2070 | H | 300s | 464 | 3.09 | 102% |
| 23:57:37 | light | NGC 2070 | H | 300s | 459 | 3.09 | 101% |
| 00:02:39 | light | NGC 2070 | H | 300s | 453 | 3.10 | 100% |
| 00:08:09 | light | NGC 2070 | O | 300s | 512 | 3.11 | 104% |
| 00:13:10 | light | NGC 2070 | O | 300s | 478 | 3.23 | 98% |
| 00:18:35 | light | NGC 2070 | O | 300s | 382 | 3.53 | 78% |
| 00:23:36 | light | NGC 2070 | O | 300s | 371 | 3.58 | 76% |
| 00:29:50 | light | NGC 2070 | S | 300s | 748 | 3.37 | 85% |
| 00:34:51 | light | NGC 2070 | S | 300s | 710 | 3.50 | 81% |
| 00:40:06 | light | NGC 2070 | S | 300s | 722 | 3.46 | 82% |
| 00:45:08 | light | NGC 2070 | S | 300s | 754 | 3.42 | 86% |
| 00:51:22 | light | NGC 2070 | H | 300s | 395 | 3.39 | 87% |
| 00:56:23 | light | NGC 2070 | H | 300s | 400 | 3.33 | 88% |
| 00:57:10 | autofocus | NGC 2070 | L | 5s | 558 | 2.03 | — |
| 00:57:30 | autofocus | NGC 2070 | L | 5s | 134 | 5.97 | — |
| 00:57:50 | autofocus | NGC 2070 | L | 5s | 190 | 4.61 | — |
| 00:58:05 | autofocus | NGC 2070 | L | 5s | 259 | 3.53 | — |
| 00:58:20 | autofocus | NGC 2070 | L | 5s | 419 | 2.48 | — |
| 00:58:40 | autofocus | NGC 2070 | L | 5s | 582 | 1.96 | — |
| 00:59:00 | autofocus | NGC 2070 | L | 5s | 608 | 1.87 | — |
| 00:59:20 | autofocus | NGC 2070 | L | 5s | 453 | 2.40 | — |
| 00:59:40 | autofocus | NGC 2070 | L | 5s | 318 | 3.21 | — |
| 00:59:55 | autofocus | NGC 2070 | L | 5s | 236 | 4.25 | — |
| 01:00:10 | autofocus | NGC 2070 | L | 5s | 181 | 5.18 | — |
| 01:00:30 | autofocus | NGC 2070 | L | 5s | 606 | 1.88 | — |
| 01:06:41 | light | NGC 2070 | H | 300s | 453 | 3.10 | 100% |
| 01:11:42 | light | NGC 2070 | H | 300s | 409 | 3.27 | 90% |
| 01:17:31 | light | NGC 2070 | O | 300s | 412 | 3.41 | 84% |
| 01:22:32 | light | NGC 2070 | O | 300s | 453 | 3.29 | 92% |
| 01:28:06 | light | NGC 2070 | O | 300s | 495 | 3.18 | 101% |
| 01:33:08 | light | NGC 2070 | O | 300s | 488 | 3.21 | 100% |
| 01:38:58 | light | NGC 2070 | S | 300s | 811 | 3.25 | 92% |
| 01:44:00 | light | NGC 2070 | S | 300s | 829 | 3.19 | 94% |
| 01:49:34 | light | NGC 2070 | S | 300s | 842 | 3.17 | 96% |
| 01:54:36 | light | NGC 2070 | S | 300s | 831 | 3.22 | 95% |
| 02:00:47 | light | NGC 2070 | H | 300s | 372 | 3.48 | 82% |
| 02:05:48 | light | NGC 2070 | H | 300s | 345 | 3.57 | 76% |
| 02:06:35 | autofocus | NGC 2070 | L | 5s | 627 | 1.99 | — |
| 02:06:55 | autofocus | NGC 2070 | L | 5s | 135 | 5.82 | — |
| 02:07:15 | autofocus | NGC 2070 | L | 5s | 206 | 4.42 | — |
| 02:07:35 | autofocus | NGC 2070 | L | 5s | 287 | 3.30 | — |
| 02:07:50 | autofocus | NGC 2070 | L | 5s | 416 | 2.56 | — |
| 02:08:10 | autofocus | NGC 2070 | L | 5s | 586 | 2.02 | — |
| 02:08:30 | autofocus | NGC 2070 | L | 5s | 587 | 2.08 | — |
| 02:08:50 | autofocus | NGC 2070 | L | 5s | 458 | 2.53 | — |
| 02:09:10 | autofocus | NGC 2070 | L | 5s | 308 | 3.44 | — |
| 02:09:25 | autofocus | NGC 2070 | L | 5s | 209 | 4.54 | — |
| 02:09:45 | autofocus | NGC 2070 | L | 5s | 698 | 1.79 | — |
| 02:15:56 | light | NGC 2070 | H | 300s | 422 | 3.20 | 93% |
| 02:20:57 | light | NGC 2070 | H | 300s | 434 | 3.19 | 96% |
| 02:28:22 | light | NGC 2070 | O | 300s | 459 | 3.26 | 94% |
| 02:33:23 | light | NGC 2070 | O | 300s | 496 | 3.17 | 101% |
| 02:38:52 | light | NGC 2070 | O | 300s | 487 | 3.18 | 99% |
| 02:43:53 | light | NGC 2070 | O | 300s | 490 | 3.20 | 100% |
| 02:50:08 | light | NGC 2070 | S | 300s | 862 | 3.18 | 98% |
| 02:55:10 | light | NGC 2070 | S | 300s | 879 | 3.15 | 100% |
| 03:00:46 | light | NGC 2070 | S | 300s | 898 | 3.09 | 102% |
| 03:05:48 | light | NGC 2070 | S | 300s | 939 | 3.05 | 107% |
| 03:11:57 | light | NGC 2070 | H | 300s | 452 | 3.11 | 100% |
| 03:16:59 | light | NGC 2070 | H | 300s | 469 | 3.09 | 104% |
| 03:22:17 | light | NGC 2070 | H | 300s | 499 | 2.98 | 110% |
| 03:27:19 | light | NGC 2070 | H | 300s | 495 | 3.00 | 109% |
| 03:34:26 | light | NGC 2070 | O | 300s | 466 | 3.26 | 95% |
| 03:39:27 | light | NGC 2070 | O | 300s | 545 | 3.07 | 111% |
| 03:44:58 | light | NGC 2070 | O | 300s | 530 | 3.07 | 108% |
| 03:49:59 | light | NGC 2070 | O | 300s | 491 | 3.19 | 100% |
| 03:56:11 | light | NGC 2070 | S | 300s | 902 | 3.11 | 103% |
| 04:01:12 | light | NGC 2070 | S | 300s | 912 | 3.09 | 104% |
| 04:06:50 | light | NGC 2070 | S | 300s | 892 | 3.13 | 101% |
| 04:11:52 | light | NGC 2070 | S | 300s | 884 | 3.16 | 101% |
| 04:18:02 | autofocus | NGC 2070 | H | 300s | 513 | 2.95 | — |
| 04:18:26 | autofocus | NGC 2070 | L | 5s | 728 | 1.77 | — |
| 04:18:45 | autofocus | NGC 2070 | L | 5s | 169 | 5.84 | — |
| 04:19:00 | autofocus | NGC 2070 | L | 5s | 243 | 4.34 | — |
| 04:19:20 | autofocus | NGC 2070 | L | 5s | 357 | 3.13 | — |
| 04:19:35 | autofocus | NGC 2070 | L | 5s | 536 | 2.27 | — |
| 04:19:55 | autofocus | NGC 2070 | L | 5s | 715 | 1.75 | — |
| 04:20:15 | autofocus | NGC 2070 | L | 5s | 633 | 1.92 | — |
| 04:20:35 | autofocus | NGC 2070 | L | 5s | 478 | 2.53 | — |
| 04:20:50 | autofocus | NGC 2070 | L | 5s | 344 | 3.44 | — |
| 04:21:05 | autofocus | NGC 2070 | L | 5s | 233 | 4.58 | — |
| 04:21:25 | autofocus | NGC 2070 | L | 5s | 687 | 1.86 | — |
| 04:27:38 | light | NGC 2070 | H | 300s | 459 | 3.08 | 101% |
| 04:33:16 | light | NGC 2070 | H | 300s | 459 | 3.10 | 101% |
| 04:38:17 | light | NGC 2070 | H | 300s | 471 | 3.03 | 104% |
| 04:45:31 | light | NGC 2070 | O | 300s | 445 | 3.16 | 91% |
| 04:50:32 | light | NGC 2070 | O | 300s | 543 | 2.97 | 111% |
| 04:56:08 | light | NGC 2070 | O | 300s | 508 | 3.02 | 104% |
| 05:01:09 | light | NGC 2070 | O | 300s | 535 | 2.96 | 109% |
| 05:07:21 | light | NGC 2070 | S | 300s | 1024 | 2.84 | 116% |
| 05:12:22 | light | NGC 2070 | S | 300s | 927 | 2.96 | 105% |
| 05:17:48 | light | NGC 2070 | S | 300s | 914 | 2.95 | 104% |
| 05:22:49 | light | NGC 2070 | S | 300s | 847 | 2.91 | 96% |
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.