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: 03-09 (93), 03-10 (93), 03-11 (93), 03-12 (93), 03-13 (93) — by astronomy; check the weather when the night is within four days.

2037-03-09astronomy score per night — click a bar for that night2037-04-07

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-03-09 Mon	93	—	unknown	21:55–05:10 (good, 7.25 h)	50.2° 01:40	9.26	39%	86.7°
2037-03-10 Tue	93	—	unknown	21:50–05:10 (good, 7.33 h)	50.2° 01:35	9.21	29%	98.9°
2037-03-11 Wed	93	—	unknown	21:45–05:10 (good, 7.42 h)	50.2° 01:30	9.16	21%	111.0°
2037-03-12 Thu	93	—	unknown	21:40–05:05 (good, 7.42 h)	50.2° 01:30	9.11	14%	122.9°
2037-03-13 Fri	93	—	unknown	21:40–05:05 (good, 7.42 h)	50.2° 01:25	9.06	8%	134.8°
2037-03-14 Sat	93	—	unknown	21:35–05:05 (good, 7.5 h)	50.2° 01:20	9.01	4%	146.6°
2037-03-15 Sun	93	—	unknown	21:30–05:00 (good, 7.5 h)	50.2° 01:15	8.96	1%	158.4°
2037-03-16 Mon	93	—	unknown	21:25–05:00 (good, 7.58 h)	50.2° 01:15	8.91	0%	170.3°
2037-03-17 Tue	93	—	unknown	21:20–04:55 (good, 7.58 h)	50.2° 01:10	8.86	1%	177.8°
2037-03-18 Wed	93	—	unknown	21:20–04:55 (good, 7.58 h)	50.2° 01:05	8.81	4%	165.7°
2037-03-19 Thu	93	—	unknown	21:15–04:55 (good, 7.67 h)	50.2° 01:00	8.76	8%	153.6°
2037-03-20 Fri	93	—	unknown	21:10–04:50 (good, 7.67 h)	50.2° 00:55	8.7	14%	141.2°
2037-03-21 Sat	93	—	unknown	21:10–04:45 (good, 7.58 h)	50.2° 00:55	8.65	22%	128.7°
2037-03-22 Sun	93	—	unknown	21:05–04:40 (good, 7.58 h)	50.2° 00:50	8.6	31%	115.9°
2037-03-23 Mon	93	—	unknown	21:05–04:35 (good, 7.5 h)	50.2° 00:45	8.55	41%	102.9°
2037-03-24 Tue	91	—	unknown	21:10–04:35 (good, 7.42 h)	50.2° 00:40	8.5	52%	89.5°
2037-03-25 Wed	86	—	unknown	21:40–04:30 (good, 6.83 h)	50.2° 00:35	8.44	63%	75.8°
2037-03-26 Thu	81	—	unknown	23:50–04:25 (good, 4.58 h)	50.2° 00:35	8.39	73%	61.6°
2037-03-27 Fri	53	—	unknown	20:50–04:40 (marginal, 7.83 h)	50.2° 00:30	8.34	83%	47.1°
2037-03-28 Sat	31	—	unknown	22:50–05:30 (marginal, 5.67 h)	50.2° 00:25	8.28	91%	32.2°
2037-03-29 Sun	23	—	unknown	01:55–05:15 (marginal, 3.33 h)	50.2° 01:20	8.23	97%	17.2°
2037-03-30 Mon	20	—	unknown	03:15–04:55 (marginal, 1.67 h)	50.1° 01:15	8.17	100%	2.1°
2037-03-31 Tue	24	—	unknown	21:25–01:55 (marginal, 4.5 h)	50.2° 01:15	8.12	99%	13.0°
2037-04-01 Wed	35	—	unknown	21:25–04:40 (marginal, 7.25 h)	50.2° 01:10	8.06	96%	27.7°
2037-04-02 Thu	84	—	unknown	21:25–22:30 (good, 1.08 h)	50.2° 01:05	8.01	91%	42.1°
2037-04-03 Fri	90	—	unknown	21:30–02:00 (good, 4.5 h)	50.2° 01:00	7.95	84%	56.0°
2037-04-04 Sat	93	—	unknown	21:30–03:55 (good, 6.42 h)	50.2° 01:00	7.9	75%	69.5°
2037-04-05 Sun	93	—	unknown	21:30–04:25 (good, 6.92 h)	50.2° 00:55	7.84	65%	82.6°
2037-04-06 Mon	93	—	unknown	21:30–04:30 (good, 7.0 h)	50.2° 00:50	7.79	55%	95.2°
2037-04-07 Tue	93	—	unknown	21:35–04:30 (good, 6.92 h)	50.2° 00:45	7.73	46%	107.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-03-09&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.