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: 02-08 (93), 02-09 (93), 02-10 (93), 02-11 (93), 02-12 (93) — by astronomy; check the weather when the night is within four days.

2037-02-08astronomy score per night — click a bar for that night2037-03-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-02-08 Sun	93	—	unknown	23:45–05:50 (good, 6.08 h)	50.2° 03:35	10.5	33%	64.8°
2037-02-09 Mon	93	—	unknown	23:45–05:50 (good, 6.08 h)	50.2° 03:30	10.46	24%	77.4°
2037-02-10 Tue	93	—	unknown	23:40–05:50 (good, 6.17 h)	50.2° 03:25	10.43	16%	89.8°
2037-02-11 Wed	93	—	unknown	23:35–05:50 (good, 6.25 h)	50.2° 03:20	10.39	9%	101.9°
2037-02-12 Thu	93	—	unknown	23:30–05:50 (good, 6.33 h)	50.2° 03:20	10.35	4%	114.0°
2037-02-13 Fri	93	—	unknown	23:30–05:45 (good, 6.25 h)	50.2° 03:15	10.31	1%	125.9°
2037-02-14 Sat	93	—	unknown	23:25–05:45 (good, 6.33 h)	50.2° 03:10	10.27	0%	137.8°
2037-02-15 Sun	93	—	unknown	23:20–05:45 (good, 6.42 h)	50.2° 03:05	10.23	0%	149.6°
2037-02-16 Mon	93	—	unknown	23:15–05:45 (good, 6.5 h)	50.2° 03:05	10.19	3%	161.4°
2037-02-17 Tue	93	—	unknown	23:10–05:40 (good, 6.5 h)	50.2° 03:00	10.15	7%	173.3°
2037-02-18 Wed	93	—	unknown	23:10–05:40 (good, 6.5 h)	50.2° 02:55	10.11	12%	174.8°
2037-02-19 Thu	93	—	unknown	23:05–05:40 (good, 6.58 h)	50.2° 02:50	10.07	19%	162.8°
2037-02-20 Fri	93	—	unknown	23:00–05:40 (good, 6.67 h)	50.2° 02:45	10.03	27%	150.6°
2037-02-21 Sat	93	—	unknown	23:00–05:35 (good, 6.58 h)	50.2° 02:45	9.98	36%	138.2°
2037-02-22 Sun	93	—	unknown	22:55–05:35 (good, 6.67 h)	50.2° 02:40	9.94	46%	125.5°
2037-02-23 Mon	93	—	unknown	22:55–05:35 (good, 6.67 h)	50.2° 02:35	9.9	57%	112.5°
2037-02-24 Tue	93	—	unknown	23:05–05:30 (good, 6.42 h)	50.2° 02:30	9.86	68%	99.0°
2037-02-25 Wed	90	—	unknown	23:35–05:30 (good, 5.92 h)	50.2° 02:25	9.81	78%	85.0°
2037-02-26 Thu	84	—	unknown	01:40–05:30 (good, 3.83 h)	50.2° 02:25	9.77	86%	70.6°
2037-02-27 Fri	50	—	unknown	22:45–05:25 (marginal, 6.67 h)	50.2° 02:20	9.72	94%	55.7°
2037-02-28 Sat	31	—	unknown	00:35–05:25 (marginal, 4.83 h)	50.2° 02:15	9.68	98%	40.6°
2037-03-01 Sun	20	—	unknown	03:10–05:25 (marginal, 2.25 h)	50.2° 02:10	9.63	100%	25.3°
2037-03-02 Mon	19	—	unknown	03:30–05:25 (marginal, 1.92 h)	50.2° 02:10	9.59	99%	10.1°
2037-03-03 Tue	24	—	unknown	22:20–05:20 (marginal, 7.0 h)	50.2° 02:05	9.54	94%	5.0°
2037-03-04 Wed	36	—	unknown	21:55–05:20 (marginal, 7.42 h)	50.2° 02:00	9.49	88%	19.7°
2037-03-05 Thu	79	—	unknown	22:10–22:40 (good, 0.5 h)	50.2° 01:55	9.45	79%	34.0°
2037-03-06 Fri	87	—	unknown	22:05–03:10 (good, 5.08 h)	50.2° 01:50	9.4	69%	47.8°
2037-03-07 Sat	92	—	unknown	22:00–05:05 (good, 7.08 h)	50.2° 01:50	9.35	59%	61.2°
2037-03-08 Sun	93	—	unknown	21:55–05:15 (good, 7.33 h)	50.2° 01:45	9.3	49%	74.1°
2037-03-09 Mon	93	—	unknown	21:55–05:10 (good, 7.25 h)	50.2° 01:40	9.26	39%	86.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-02-08&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.