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 3C 273: 01-20 (93), 01-21 (93), 02-03 (93), 02-04 (93), 02-05 (93) — by astronomy; check the weather when the night is within four days.

2043-01-20astronomy score per night — click a bar for that night2043-02-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-01-20 Tue	93	—	unknown	01:15–06:10 (good, 4.92 h)	50.1° 04:50	11.11	78%	120.9°
2043-01-21 Wed	93	—	unknown	01:20–06:05 (good, 4.75 h)	50.1° 04:45	11.09	86%	106.8°
2043-01-22 Thu	73	—	unknown	02:00–06:05 (good, 4.08 h)	50.1° 04:45	11.06	93%	92.8°
2043-01-23 Fri	56	—	unknown	03:50–06:05 (good, 2.25 h)	50.1° 04:40	11.03	98%	78.9°
2043-01-24 Sat	40	—	unknown	00:55–06:05 (marginal, 5.17 h)	50.1° 04:35	11.0	100%	65.2°
2043-01-25 Sun	28	—	unknown	01:10–06:05 (marginal, 4.92 h)	50.1° 04:30	10.98	99%	51.8°
2043-01-26 Mon	20	—	unknown	03:00–06:05 (marginal, 3.08 h)	50.1° 04:25	10.95	97%	38.7°
2043-01-27 Tue	17	—	unknown	03:35–06:05 (marginal, 2.5 h)	50.1° 04:25	10.92	92%	26.0°
2043-01-28 Wed	22	—	unknown	00:45–06:05 (marginal, 5.33 h)	50.1° 04:20	10.89	86%	13.8°
2043-01-29 Thu	29	—	unknown	00:20–06:00 (marginal, 5.67 h)	50.1° 04:15	10.86	79%	4.4°
2043-01-30 Fri	40	—	unknown	00:05–06:00 (marginal, 5.92 h)	50.1° 04:10	10.83	70%	12.1°
2043-01-31 Sat	55	—	unknown	23:55–06:00 (marginal, 6.08 h)	50.1° 04:10	10.79	62%	23.6°
2043-02-01 Sun	83	—	unknown	00:15–06:00 (good, 5.75 h)	50.1° 04:05	10.76	52%	35.3°
2043-02-02 Mon	89	—	unknown	00:15–06:00 (good, 5.75 h)	50.1° 04:00	10.73	43%	47.0°
2043-02-03 Tue	93	—	unknown	00:10–06:00 (good, 5.83 h)	50.1° 03:55	10.69	34%	58.9°
2043-02-04 Wed	93	—	unknown	00:05–05:55 (good, 5.83 h)	50.1° 03:50	10.66	25%	71.0°
2043-02-05 Thu	93	—	unknown	00:00–05:55 (good, 5.92 h)	50.1° 03:50	10.63	17%	83.4°
2043-02-06 Fri	93	—	unknown	23:55–05:55 (good, 6.0 h)	50.1° 03:45	10.59	10%	96.1°
2043-02-07 Sat	93	—	unknown	23:55–05:55 (good, 6.0 h)	50.1° 03:40	10.55	5%	109.1°
2043-02-08 Sun	93	—	unknown	23:50–05:55 (good, 6.08 h)	50.1° 03:35	10.52	1%	122.4°
2043-02-09 Mon	93	—	unknown	23:45–05:50 (good, 6.08 h)	50.1° 03:30	10.48	0%	136.1°
2043-02-10 Tue	93	—	unknown	23:40–05:50 (good, 6.17 h)	50.1° 03:30	10.44	2%	150.0°
2043-02-11 Wed	93	—	unknown	23:40–05:50 (good, 6.17 h)	50.1° 03:25	10.41	5%	163.9°
2043-02-12 Thu	93	—	unknown	23:35–05:50 (good, 6.25 h)	50.1° 03:20	10.37	12%	175.4°
2043-02-13 Fri	93	—	unknown	23:30–05:45 (good, 6.25 h)	50.1° 03:15	10.33	20%	166.1°
2043-02-14 Sat	93	—	unknown	23:30–05:45 (good, 6.25 h)	50.1° 03:15	10.29	30%	152.2°
2043-02-15 Sun	93	—	unknown	23:25–05:45 (good, 6.33 h)	50.1° 03:10	10.25	41%	138.1°
2043-02-16 Mon	93	—	unknown	23:25–05:45 (good, 6.33 h)	50.1° 03:05	10.21	53%	124.1°
2043-02-17 Tue	93	—	unknown	23:25–05:40 (good, 6.25 h)	50.1° 03:00	10.17	64%	110.2°
2043-02-18 Wed	91	—	unknown	23:35–05:40 (good, 6.08 h)	50.1° 02:55	10.13	74%	96.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-01-20&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.