Rozhen Observation Calendar

Which nights are best for a target over the coming weeks. The astronomy mark (darkness × altitude × Moon) is computed for every night; the weather and the overall mark exist only where Open-Meteo has a forecast (the next four days) or ERA5 history (past nights) — the rest is honestly blank.

Best nights for Triangulum Pinwheel: 09-16 (100), 09-17 (100), 09-18 (100), 09-19 (100), 09-20 (100) — by astronomy; check the weather when the night is within four days.

2031-09-16astronomy score per night — click a bar for that night2031-10-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-09-16 Tue	100	—	unknown	21:45–05:30 (good, 7.75 h)	79.1° 03:15	8.41	0%	140.2°
2031-09-17 Wed	100	—	unknown	21:40–05:30 (good, 7.83 h)	79.1° 03:10	8.47	2%	150.9°
2031-09-18 Thu	100	—	unknown	21:40–05:35 (good, 7.92 h)	79.1° 03:05	8.52	5%	159.5°
2031-09-19 Fri	100	—	unknown	21:35–05:35 (good, 8.0 h)	79.1° 03:00	8.57	10%	162.0°
2031-09-20 Sat	100	—	unknown	21:30–05:35 (good, 8.08 h)	79.1° 03:00	8.62	18%	156.1°
2031-09-21 Sun	100	—	unknown	21:30–05:35 (good, 8.08 h)	79.1° 02:55	8.67	27%	145.7°
2031-09-22 Mon	100	—	unknown	21:25–05:40 (good, 8.25 h)	79.1° 02:50	8.72	37%	133.6°
2031-09-23 Tue	100	—	unknown	21:25–05:40 (good, 8.25 h)	79.1° 02:45	8.77	48%	120.7°
2031-09-24 Wed	100	—	unknown	21:25–05:40 (good, 8.25 h)	79.1° 02:40	8.82	60%	107.4°
2031-09-25 Thu	100	—	unknown	21:30–05:40 (good, 8.17 h)	79.1° 02:40	8.87	71%	93.9°
2031-09-26 Fri	100	—	unknown	22:05–05:45 (good, 7.67 h)	79.1° 02:35	8.92	81%	80.2°
2031-09-27 Sat	100	—	unknown	23:55–05:45 (good, 5.83 h)	79.1° 02:30	8.97	89%	66.5°
2031-09-28 Sun	95	—	unknown	03:45–05:45 (good, 2.0 h)	79.1° 02:25	9.02	95%	53.0°
2031-09-29 Mon	51	—	unknown	21:00–05:45 (marginal, 8.75 h)	79.1° 02:25	9.07	99%	40.1°
2031-09-30 Tue	31	—	unknown	02:55–05:45 (marginal, 2.83 h)	79.1° 02:20	9.12	100%	28.4°
2031-10-01 Wed	28	—	unknown	20:50–00:15 (marginal, 3.42 h)	79.1° 02:15	9.17	98%	19.7°
2031-10-02 Thu	35	—	unknown	20:35–01:40 (marginal, 5.08 h)	79.1° 02:10	9.22	95%	18.5°
2031-10-03 Fri	46	—	unknown	20:35–05:50 (marginal, 9.25 h)	79.1° 02:05	9.27	89%	25.1°
2031-10-04 Sat	81	—	unknown	20:35–21:15 (good, 0.67 h)	79.1° 02:05	9.31	82%	35.1°
2031-10-05 Sun	88	—	unknown	20:30–01:25 (good, 4.92 h)	79.1° 02:00	9.36	73%	46.0°
2031-10-06 Mon	94	—	unknown	20:30–04:55 (good, 8.42 h)	79.1° 01:55	9.41	64%	57.1°
2031-10-07 Tue	100	—	unknown	20:30–05:55 (good, 9.42 h)	79.1° 01:50	9.45	55%	68.4°
2031-10-08 Wed	100	—	unknown	20:25–05:55 (good, 9.5 h)	79.1° 01:45	9.5	46%	79.6°
2031-10-09 Thu	100	—	unknown	20:25–05:55 (good, 9.5 h)	79.1° 01:45	9.54	36%	90.9°
2031-10-10 Fri	100	—	unknown	20:25–06:00 (good, 9.58 h)	79.1° 01:40	9.59	27%	102.2°
2031-10-11 Sat	100	—	unknown	20:20–06:00 (good, 9.67 h)	79.1° 01:35	9.64	19%	113.6°
2031-10-12 Sun	100	—	unknown	20:20–06:00 (good, 9.67 h)	79.1° 01:30	9.68	12%	125.0°
2031-10-13 Mon	100	—	unknown	20:20–06:00 (good, 9.67 h)	79.1° 01:30	9.72	6%	136.5°
2031-10-14 Tue	100	—	unknown	20:15–06:05 (good, 9.83 h)	79.1° 01:25	9.77	2%	147.5°
2031-10-15 Wed	100	—	unknown	20:15–06:05 (good, 9.83 h)	79.1° 01:20	9.81	0%	157.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-09-16&days=30"
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&days=30&format=csv" -o m31-calendar.csv

One row per night: score_astronomy always, score_weather / score only where a forecast or history exists (null otherwise, with weather_source saying which), best window, dark hours, Moon illumination and separation, transit. 7–60 nights. Errors: 400 with invalid_date or target_unresolved. Results are cached for six hours; calculation version 2026-10-10.1.