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: 03-25 (93), 03-26 (93), 03-27 (93), 03-28 (93), 03-29 (93) — by astronomy; check the weather when the night is within four days.

2030-03-25astronomy score per night — click a bar for that night2030-04-23

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-03-25 Mon	93	—	unknown	20:50–04:15 (good, 7.42 h)	50.2° 00:40	8.46	55%	83.2°
2030-03-26 Tue	93	—	unknown	20:45–04:15 (good, 7.5 h)	50.2° 00:35	8.41	44%	96.9°
2030-03-27 Wed	93	—	unknown	20:45–04:20 (good, 7.58 h)	50.2° 00:30	8.35	34%	110.3°
2030-03-28 Thu	93	—	unknown	20:40–04:15 (good, 7.58 h)	50.2° 00:25	8.3	24%	123.3°
2030-03-29 Fri	93	—	unknown	20:35–04:15 (good, 7.67 h)	50.2° 00:20	8.24	16%	136.1°
2030-03-30 Sat	93	—	unknown	20:30–05:10 (good, 7.67 h)	50.2° 00:20	8.19	9%	148.5°
2030-03-31 Sun	93	—	unknown	21:25–05:05 (good, 7.67 h)	50.2° 01:15	8.14	4%	160.1°
2030-04-01 Mon	93	—	unknown	21:25–05:00 (good, 7.58 h)	50.2° 01:10	8.08	1%	169.2°
2030-04-02 Tue	93	—	unknown	21:25–05:00 (good, 7.58 h)	50.2° 01:05	8.03	0%	168.0°
2030-04-03 Wed	93	—	unknown	21:25–04:55 (good, 7.5 h)	50.2° 01:05	7.97	1%	158.5°
2030-04-04 Thu	93	—	unknown	21:30–04:50 (good, 7.33 h)	50.2° 01:00	7.91	4%	147.3°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-03-25&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.