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.

2044-03-21astronomy score per night — click a bar for that night2044-04-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-03-21 Mon	93	—	unknown	21:05–04:35 (good, 7.5 h)	50.1° 00:50	8.64	48%	89.1°
2044-03-22 Tue	93	—	unknown	21:00–04:35 (good, 7.58 h)	50.1° 00:50	8.58	38%	100.9°
2044-03-23 Wed	93	—	unknown	21:00–04:35 (good, 7.58 h)	50.1° 00:45	8.53	29%	112.9°
2044-03-24 Thu	93	—	unknown	20:55–04:30 (good, 7.58 h)	50.1° 00:40	8.48	21%	125.0°
2044-03-25 Fri	93	—	unknown	20:50–04:30 (good, 7.67 h)	50.1° 00:35	8.43	13%	137.5°
2044-03-26 Sat	93	—	unknown	20:45–05:25 (good, 7.67 h)	50.1° 00:30	8.37	7%	150.2°
2044-03-27 Sun	93	—	unknown	21:40–05:20 (good, 7.67 h)	50.1° 01:30	8.32	3%	162.9°
2044-03-28 Mon	93	—	unknown	21:40–05:15 (good, 7.58 h)	50.1° 01:25	8.27	0%	173.4°
2044-03-29 Tue	93	—	unknown	21:35–05:10 (good, 7.58 h)	50.1° 01:20	8.21	0%	166.9°
2044-03-30 Wed	93	—	unknown	21:30–05:10 (good, 7.67 h)	50.1° 01:15	8.16	3%	153.5°
2044-03-31 Thu	93	—	unknown	21:25–05:05 (good, 7.67 h)	50.1° 01:15	8.1	8%	139.5°
2044-04-01 Fri	93	—	unknown	21:25–05:00 (good, 7.58 h)	50.1° 01:10	8.05	16%	125.3°
2044-04-02 Sat	93	—	unknown	21:25–04:55 (good, 7.5 h)	50.1° 01:05	7.99	25%	111.0°
2044-04-03 Sun	91	—	unknown	21:30–04:55 (good, 7.42 h)	50.1° 01:00	7.94	36%	96.8°
2044-04-04 Mon	86	—	unknown	21:30–04:50 (good, 7.33 h)	50.1° 00:55	7.88	47%	82.7°
2044-04-05 Tue	81	—	unknown	22:15–04:45 (good, 6.5 h)	50.1° 00:55	7.83	59%	68.7°
2044-04-06 Wed	63	—	unknown	00:45–04:15 (good, 3.5 h)	50.1° 00:50	7.77	70%	55.0°
2044-04-07 Thu	48	—	unknown	21:35–05:05 (marginal, 7.5 h)	50.1° 00:45	7.71	79%	41.4°
2044-04-08 Fri	32	—	unknown	21:55–04:50 (marginal, 6.92 h)	50.1° 00:40	7.66	87%	28.1°
2044-04-09 Sat	25	—	unknown	23:00–04:35 (marginal, 5.58 h)	50.1° 00:35	7.6	94%	15.4°
2044-04-10 Sun	22	—	unknown	21:40–04:20 (marginal, 6.67 h)	50.1° 00:35	7.54	98%	6.3°
2044-04-11 Mon	23	—	unknown	21:40–04:10 (marginal, 6.5 h)	50.1° 00:30	7.49	100%	13.3°
2044-04-12 Tue	29	—	unknown	21:40–04:05 (marginal, 6.42 h)	50.1° 00:25	7.43	100%	25.3°
2044-04-13 Wed	44	—	unknown	21:40–04:10 (marginal, 6.5 h)	50.1° 00:20	7.37	98%	37.4°
2044-04-14 Thu	89	—	unknown	21:45–23:40 (good, 1.92 h)	50.1° 00:20	7.31	94%	49.5°
2044-04-15 Fri	93	—	unknown	21:45–02:05 (good, 4.33 h)	50.1° 00:15	7.26	88%	61.5°
2044-04-16 Sat	93	—	unknown	21:45–03:25 (good, 5.67 h)	50.1° 00:10	7.2	81%	73.3°
2044-04-17 Sun	93	—	unknown	21:50–03:40 (good, 5.83 h)	50.1° 00:05	7.14	73%	85.1°
2044-04-18 Mon	93	—	unknown	21:50–03:40 (good, 5.83 h)	50.1° 00:00	7.08	65%	96.9°
2044-04-19 Tue	93	—	unknown	21:50–03:45 (good, 5.92 h)	50.1° 00:00	7.02	55%	108.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-03-21&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.