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: 02-20 (93), 02-21 (93), 02-22 (93), 02-23 (93), 02-24 (93) — by astronomy; check the weather when the night is within four days.

2044-02-11astronomy score per night — click a bar for that night2044-03-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-02-11 Thu	45	—	unknown	23:50–05:50 (marginal, 6.0 h)	50.1° 03:25	10.42	98%	60.7°
2044-02-12 Fri	30	—	unknown	00:55–05:50 (marginal, 4.92 h)	50.1° 03:20	10.38	100%	46.4°
2044-02-13 Sat	20	—	unknown	03:25–05:50 (marginal, 2.42 h)	50.1° 03:15	10.34	99%	32.5°
2044-02-14 Sun	19	—	unknown	03:10–05:45 (marginal, 2.58 h)	50.1° 03:15	10.3	96%	19.1°
2044-02-15 Mon	24	—	unknown	23:30–05:45 (marginal, 6.25 h)	50.1° 03:10	10.26	92%	7.7°
2044-02-16 Tue	32	—	unknown	23:05–05:45 (marginal, 6.67 h)	50.1° 03:05	10.22	85%	10.5°
2044-02-17 Wed	46	—	unknown	22:45–05:45 (marginal, 7.0 h)	50.1° 03:00	10.18	77%	22.0°
2044-02-18 Thu	82	—	unknown	23:10–02:40 (good, 3.5 h)	50.1° 03:00	10.14	68%	34.1°
2044-02-19 Fri	89	—	unknown	23:05–05:40 (good, 6.58 h)	50.1° 02:55	10.1	59%	46.0°
2044-02-20 Sat	93	—	unknown	23:05–05:40 (good, 6.58 h)	50.1° 02:50	10.06	49%	57.8°
2044-02-21 Sun	93	—	unknown	23:00–05:35 (good, 6.58 h)	50.1° 02:45	10.01	40%	69.6°
2044-02-22 Mon	93	—	unknown	22:55–05:35 (good, 6.67 h)	50.1° 02:40	9.97	31%	81.3°
2044-02-23 Tue	93	—	unknown	22:50–05:35 (good, 6.75 h)	50.1° 02:40	9.93	22%	93.2°
2044-02-24 Wed	93	—	unknown	22:50–05:35 (good, 6.75 h)	50.1° 02:35	9.89	15%	105.1°
2044-02-25 Thu	93	—	unknown	22:45–05:30 (good, 6.75 h)	50.1° 02:30	9.84	9%	117.3°
2044-02-26 Fri	93	—	unknown	22:40–05:30 (good, 6.83 h)	50.1° 02:25	9.8	4%	129.7°
2044-02-27 Sat	93	—	unknown	22:35–05:30 (good, 6.92 h)	50.1° 02:20	9.75	1%	142.3°
2044-02-28 Sun	93	—	unknown	22:30–05:25 (good, 6.92 h)	50.1° 02:20	9.71	0%	155.0°
2044-02-29 Mon	93	—	unknown	22:30–05:25 (good, 6.92 h)	50.1° 02:15	9.66	1%	167.4°
2044-03-01 Tue	93	—	unknown	22:25–05:25 (good, 7.0 h)	50.1° 02:10	9.62	5%	173.3°
2044-03-02 Wed	93	—	unknown	22:20–05:20 (good, 7.0 h)	50.1° 02:05	9.57	11%	162.6°
2044-03-03 Thu	93	—	unknown	22:20–05:20 (good, 7.0 h)	50.1° 02:05	9.53	19%	149.3°
2044-03-04 Fri	93	—	unknown	22:15–05:20 (good, 7.08 h)	50.1° 02:00	9.48	28%	135.5°
2044-03-05 Sat	93	—	unknown	22:10–05:15 (good, 7.08 h)	50.1° 01:55	9.43	39%	121.6°
2044-03-06 Sun	93	—	unknown	22:15–05:15 (good, 7.0 h)	50.1° 01:50	9.38	51%	107.6°
2044-03-07 Mon	90	—	unknown	22:20–05:15 (good, 6.92 h)	50.1° 01:45	9.34	62%	93.5°
2044-03-08 Tue	85	—	unknown	23:10–05:10 (good, 6.0 h)	50.1° 01:45	9.29	73%	79.4°
2044-03-09 Wed	79	—	unknown	01:30–05:10 (good, 3.67 h)	50.1° 01:40	9.24	82%	65.4°
2044-03-10 Thu	49	—	unknown	22:00–05:10 (marginal, 7.17 h)	50.1° 01:35	9.19	90%	51.4°
2044-03-11 Fri	32	—	unknown	23:55–05:05 (marginal, 5.17 h)	50.1° 01:30	9.14	96%	37.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-02-11&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.