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: 04-05 (93), 04-06 (93), 04-07 (93), 04-08 (93), 04-20 (93) — by astronomy; check the weather when the night is within four days.

2030-04-05astronomy score per night — click a bar for that night2030-05-04

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-04-05 Fri	93	—	unknown	21:30–04:45 (good, 7.25 h)	50.2° 00:55	7.86	8%	135.9°
2030-04-06 Sat	93	—	unknown	21:30–04:45 (good, 7.25 h)	50.2° 00:50	7.8	14%	124.3°
2030-04-07 Sun	93	—	unknown	21:35–04:40 (good, 7.08 h)	50.2° 00:45	7.75	21%	112.7°
2030-04-08 Mon	93	—	unknown	21:35–04:35 (good, 7.0 h)	50.2° 00:45	7.69	29%	101.1°
2030-04-09 Tue	91	—	unknown	21:35–04:30 (good, 6.92 h)	50.2° 00:40	7.63	38%	89.2°
2030-04-10 Wed	88	—	unknown	21:35–04:25 (good, 6.83 h)	50.2° 00:35	7.58	48%	77.2°
2030-04-11 Thu	84	—	unknown	22:00–04:25 (good, 6.42 h)	50.2° 00:30	7.52	58%	65.0°
2030-04-12 Fri	80	—	unknown	00:05–04:20 (good, 4.25 h)	50.2° 00:25	7.46	68%	52.4°
2030-04-13 Sat	53	—	unknown	21:40–04:45 (marginal, 7.08 h)	50.2° 00:25	7.41	77%	39.5°
2030-04-14 Sun	34	—	unknown	21:45–04:30 (marginal, 6.75 h)	50.2° 00:20	7.35	86%	26.5°
2030-04-15 Mon	27	—	unknown	21:45–04:15 (marginal, 6.5 h)	50.2° 00:15	7.29	93%	14.3°
2030-04-16 Tue	23	—	unknown	21:45–04:00 (marginal, 6.25 h)	50.2° 00:10	7.23	98%	10.4°
2030-04-17 Wed	25	—	unknown	21:45–03:50 (marginal, 6.08 h)	50.2° 00:10	7.18	100%	21.1°
2030-04-18 Thu	35	—	unknown	21:50–03:50 (marginal, 6.0 h)	50.2° 00:05	7.12	99%	35.1°
2030-04-19 Fri	83	—	unknown	21:50–22:55 (good, 1.08 h)	50.2° 00:00	7.06	95%	49.7°
2030-04-20 Sat	93	—	unknown	21:50–01:50 (good, 4.0 h)	50.2° 23:55	7.0	89%	64.4°
2030-04-21 Sun	93	—	unknown	21:55–03:15 (good, 5.33 h)	50.2° 23:50	6.94	80%	78.9°
2030-04-22 Mon	93	—	unknown	21:55–03:25 (good, 5.5 h)	50.2° 23:50	6.89	70%	93.1°
2030-04-23 Tue	93	—	unknown	21:55–03:25 (good, 5.5 h)	50.2° 23:45	6.83	59%	106.9°
2030-04-24 Wed	93	—	unknown	22:00–03:30 (good, 5.5 h)	50.2° 23:40	6.77	48%	120.2°
2030-04-25 Thu	93	—	unknown	22:00–03:25 (good, 5.42 h)	50.2° 23:35	6.71	38%	133.1°
2030-04-26 Fri	93	—	unknown	22:00–03:25 (good, 5.42 h)	50.2° 23:30	6.65	28%	145.6°
2030-04-27 Sat	93	—	unknown	22:05–03:20 (good, 5.25 h)	50.2° 23:30	6.59	20%	157.4°
2030-04-28 Sun	93	—	unknown	22:05–03:15 (good, 5.17 h)	50.2° 23:25	6.54	12%	167.4°
2030-04-29 Mon	93	—	unknown	22:05–03:10 (good, 5.08 h)	50.2° 23:20	6.48	7%	169.5°
2030-04-30 Tue	93	—	unknown	22:10–03:10 (good, 5.0 h)	50.2° 23:15	6.42	3%	161.2°
2030-05-01 Wed	93	—	unknown	22:10–03:05 (good, 4.92 h)	50.2° 23:15	6.36	0%	150.4°
2030-05-02 Thu	93	—	unknown	22:10–03:00 (good, 4.83 h)	50.2° 23:10	6.3	0%	139.0°
2030-05-03 Fri	93	—	unknown	22:15–02:55 (good, 4.67 h)	50.2° 23:05	6.25	2%	127.5°
2030-05-04 Sat	93	—	unknown	22:15–02:55 (good, 4.67 h)	50.2° 23:00	6.19	5%	115.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-04-05&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.