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: 03-07 (93), 03-08 (93), 03-09 (93), 03-23 (93), 03-24 (93) — by astronomy; check the weather when the night is within four days.

2041-03-07astronomy score per night — click a bar for that night2041-04-05

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-03-07 Thu	93	—	unknown	22:05–05:15 (good, 7.17 h)	50.1° 01:50	9.35	33%	128.0°
2041-03-08 Fri	93	—	unknown	22:05–05:15 (good, 7.17 h)	50.1° 01:45	9.3	43%	115.2°
2041-03-09 Sat	93	—	unknown	22:05–05:10 (good, 7.08 h)	50.1° 01:40	9.25	53%	102.7°
2041-03-10 Sun	89	—	unknown	22:10–05:10 (good, 7.0 h)	50.1° 01:35	9.21	62%	90.5°
2041-03-11 Mon	85	—	unknown	23:00–05:10 (good, 6.17 h)	50.1° 01:30	9.16	71%	78.5°
2041-03-12 Tue	80	—	unknown	00:55–05:05 (good, 4.17 h)	50.1° 01:30	9.11	80%	66.6°
2041-03-13 Wed	55	—	unknown	21:40–05:05 (marginal, 7.42 h)	50.1° 01:25	9.06	86%	54.8°
2041-03-14 Thu	38	—	unknown	22:05–05:00 (marginal, 6.92 h)	50.1° 01:20	9.01	92%	43.0°
2041-03-15 Fri	25	—	unknown	01:25–05:00 (marginal, 3.58 h)	50.1° 01:15	8.96	96%	31.2°
2041-03-16 Sat	21	—	unknown	02:30–05:00 (marginal, 2.5 h)	50.1° 01:15	8.91	99%	19.2°
2041-03-17 Sun	20	—	unknown	02:55–04:50 (marginal, 1.92 h)	50.1° 01:10	8.86	100%	7.2°
2041-03-18 Mon	22	—	unknown	21:25–01:15 (marginal, 3.83 h)	50.1° 01:05	8.81	99%	5.4°
2041-03-19 Tue	31	—	unknown	21:05–04:40 (marginal, 7.58 h)	50.1° 01:00	8.75	96%	17.6°
2041-03-20 Wed	62	—	unknown	21:10–21:25 (good, 0.25 h)	50.1° 00:55	8.7	91%	30.2°
2041-03-21 Thu	86	—	unknown	21:05–23:05 (good, 2.0 h)	50.1° 00:55	8.65	84%	42.9°
2041-03-22 Fri	91	—	unknown	21:00–02:45 (good, 5.75 h)	50.1° 00:50	8.6	76%	55.9°
2041-03-23 Sat	93	—	unknown	21:00–04:10 (good, 7.17 h)	50.1° 00:45	8.55	66%	69.1°
2041-03-24 Sun	93	—	unknown	20:55–04:20 (good, 7.42 h)	50.1° 00:40	8.49	56%	82.6°
2041-03-25 Mon	93	—	unknown	20:50–04:20 (good, 7.5 h)	50.1° 00:35	8.44	44%	96.5°
2041-03-26 Tue	93	—	unknown	20:45–04:20 (good, 7.58 h)	50.1° 00:35	8.39	33%	110.6°
2041-03-27 Wed	93	—	unknown	20:45–04:20 (good, 7.58 h)	50.1° 00:30	8.33	23%	125.0°
2041-03-28 Thu	93	—	unknown	20:40–04:15 (good, 7.58 h)	50.1° 00:25	8.28	14%	139.6°
2041-03-29 Fri	93	—	unknown	20:35–04:15 (good, 7.67 h)	50.1° 00:20	8.23	7%	154.4°
2041-03-30 Sat	93	—	unknown	20:30–05:10 (good, 7.67 h)	50.1° 00:20	8.17	2%	169.2°
2041-03-31 Sun	93	—	unknown	21:25–05:05 (good, 7.67 h)	50.1° 01:15	8.12	0%	175.7°
2041-04-01 Mon	93	—	unknown	21:25–05:00 (good, 7.58 h)	50.1° 01:10	8.06	1%	161.4°
2041-04-02 Tue	93	—	unknown	21:25–04:55 (good, 7.5 h)	50.1° 01:05	8.01	5%	147.2°
2041-04-03 Wed	93	—	unknown	21:30–04:55 (good, 7.42 h)	50.1° 01:00	7.95	10%	133.4°
2041-04-04 Thu	93	—	unknown	21:30–04:50 (good, 7.33 h)	50.1° 01:00	7.9	18%	120.1°
2041-04-05 Fri	93	—	unknown	21:30–04:45 (good, 7.25 h)	50.1° 00:55	7.84	26%	107.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-03-07&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.