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: 04-13 (93), 04-14 (93), 04-15 (93), 04-16 (93), 04-17 (93) — by astronomy; check the weather when the night is within four days.

2047-04-03astronomy score per night — click a bar for that night2047-05-02

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2047-04-20 Sat	93	—	unknown	21:50–03:50 (good, 6.0 h)	50.1° 23:55	7.01	16%	156.5°
2047-04-21 Sun	93	—	unknown	21:55–03:45 (good, 5.83 h)	50.1° 23:55	6.95	10%	166.5°
2047-04-22 Mon	93	—	unknown	21:55–03:40 (good, 5.75 h)	50.1° 23:50	6.89	5%	170.1°
2047-04-23 Tue	93	—	unknown	21:55–03:35 (good, 5.67 h)	50.1° 23:45	6.83	2%	162.9°
2047-04-24 Wed	93	—	unknown	22:00–03:35 (good, 5.58 h)	50.1° 23:40	6.78	0%	152.4°
2047-04-25 Thu	93	—	unknown	22:00–03:30 (good, 5.5 h)	50.1° 23:35	6.72	1%	141.1°
2047-04-26 Fri	93	—	unknown	22:00–03:25 (good, 5.42 h)	50.1° 23:35	6.66	3%	129.6°
2047-04-27 Sat	93	—	unknown	22:05–03:20 (good, 5.25 h)	50.1° 23:30	6.6	7%	117.9°
2047-04-28 Sun	93	—	unknown	22:05–03:15 (good, 5.17 h)	50.1° 23:25	6.54	12%	106.0°
2047-04-29 Mon	91	—	unknown	22:05–03:15 (good, 5.17 h)	50.1° 23:20	6.48	19%	94.0°
2047-04-30 Tue	88	—	unknown	22:10–03:10 (good, 5.0 h)	50.1° 23:20	6.43	28%	81.7°
2047-05-01 Wed	85	—	unknown	22:10–03:05 (good, 4.92 h)	50.1° 23:15	6.37	37%	69.2°
2047-05-02 Thu	81	—	unknown	22:10–03:00 (good, 4.83 h)	50.1° 23:10	6.31	48%	56.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-04-03&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.