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: 03-21 (93), 03-22 (93), 03-23 (93), 03-24 (93), 03-25 (93) — by astronomy; check the weather when the night is within four days.

2047-03-21astronomy score per night — click a bar for that night2047-04-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-03-21 Thu	93	—	unknown	21:10–04:45 (good, 7.58 h)	50.1° 00:55	8.67	18%	124.1°
2047-03-22 Fri	93	—	unknown	21:05–04:45 (good, 7.67 h)	50.1° 00:50	8.62	12%	136.2°
2047-03-23 Sat	93	—	unknown	21:00–04:40 (good, 7.67 h)	50.1° 00:45	8.57	6%	148.0°
2047-03-24 Sun	93	—	unknown	20:55–04:35 (good, 7.67 h)	50.1° 00:45	8.52	2%	159.2°
2047-03-25 Mon	93	—	unknown	20:55–04:30 (good, 7.58 h)	50.1° 00:40	8.46	0%	168.4°
2047-03-26 Tue	93	—	unknown	20:50–04:25 (good, 7.58 h)	50.1° 00:35	8.41	0%	169.0°
2047-03-27 Wed	93	—	unknown	20:45–04:25 (good, 7.67 h)	50.1° 00:30	8.36	2%	160.3°
2047-03-28 Thu	93	—	unknown	20:40–04:20 (good, 7.67 h)	50.1° 00:30	8.3	6%	149.5°
2047-03-29 Fri	93	—	unknown	20:40–04:15 (good, 7.58 h)	50.1° 00:25	8.25	10%	138.2°
2047-03-30 Sat	93	—	unknown	20:35–05:10 (good, 7.58 h)	50.1° 00:20	8.2	17%	126.7°
2047-03-31 Sun	93	—	unknown	21:35–05:05 (good, 7.5 h)	50.1° 01:15	8.14	25%	114.9°
2047-04-01 Mon	93	—	unknown	21:35–05:05 (good, 7.5 h)	50.1° 01:10	8.09	33%	103.0°
2047-04-02 Tue	90	—	unknown	21:35–05:00 (good, 7.42 h)	50.1° 01:10	8.03	43%	90.8°
2047-04-03 Wed	87	—	unknown	21:45–04:55 (good, 7.17 h)	50.1° 01:05	7.98	53%	78.3°
2047-04-04 Thu	83	—	unknown	22:55–04:50 (good, 5.92 h)	50.1° 01:00	7.92	63%	65.4°
2047-04-05 Fri	74	—	unknown	01:40–04:20 (good, 2.67 h)	50.1° 00:55	7.87	74%	52.1°
2047-04-06 Sat	48	—	unknown	21:30–05:10 (marginal, 7.67 h)	50.1° 00:50	7.81	83%	38.5°
2047-04-07 Sun	32	—	unknown	21:45–04:55 (marginal, 7.17 h)	50.1° 00:50	7.75	91%	24.8°
2047-04-08 Mon	26	—	unknown	21:35–04:40 (marginal, 7.08 h)	50.1° 00:45	7.7	96%	12.6°
2047-04-09 Tue	24	—	unknown	21:35–04:30 (marginal, 6.92 h)	50.1° 00:40	7.64	99%	11.9°
2047-04-10 Wed	31	—	unknown	21:35–04:20 (marginal, 6.75 h)	50.1° 00:35	7.58	99%	24.2°
2047-04-11 Thu	75	—	unknown	21:40–21:50 (good, 0.17 h)	50.1° 00:30	7.53	96%	38.6°
2047-04-12 Fri	91	—	unknown	21:40–00:55 (good, 3.25 h)	50.1° 00:30	7.47	91%	53.2°
2047-04-13 Sat	93	—	unknown	21:40–03:05 (good, 5.42 h)	50.1° 00:25	7.41	83%	67.5°
2047-04-14 Sun	93	—	unknown	21:45–03:50 (good, 6.08 h)	50.1° 00:20	7.36	73%	81.6°
2047-04-15 Mon	93	—	unknown	21:45–03:55 (good, 6.17 h)	50.1° 00:15	7.3	63%	95.1°
2047-04-16 Tue	93	—	unknown	21:45–03:55 (good, 6.17 h)	50.1° 00:15	7.24	52%	108.3°
2047-04-17 Wed	93	—	unknown	21:45–03:55 (good, 6.17 h)	50.1° 00:10	7.18	42%	121.0°
2047-04-18 Thu	93	—	unknown	21:50–03:55 (good, 6.08 h)	50.1° 00:05	7.12	32%	133.3°
2047-04-19 Fri	93	—	unknown	21:50–03:55 (good, 6.08 h)	50.1° 00:00	7.07	23%	145.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-03-21&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.