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 Vega: 01-11 (20), 12-13 (19), 01-10 (18), 12-14 (17), 01-09 (17) — by astronomy; check the weather when the night is within four days.

2037-12-13astronomy score per night — click a bar for that night2038-01-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-12-13 Sun	19	—	unknown	18:35–19:10 (good, 0.58 h)	87.1° 13:30	11.48	44%	80.0°
2037-12-14 Mon	17	—	unknown	18:35–19:05 (good, 0.5 h)	87.1° 13:25	11.49	53%	85.6°
2037-12-15 Tue	15	—	unknown	18:35–19:00 (good, 0.42 h)	87.1° 13:20	11.49	62%	91.3°
2037-12-16 Wed	15	—	unknown	18:35–18:55 (good, 0.33 h)	87.1° 13:15	11.5	71%	97.0°
2037-12-17 Thu	14	—	unknown	18:35–18:50 (good, 0.25 h)	87.1° 13:15	11.5	79%	102.6°
2037-12-18 Fri	14	—	unknown	18:35–18:50 (good, 0.25 h)	87.1° 13:10	11.5	87%	107.7°
2037-12-19 Sat	14	—	unknown	18:35–18:45 (good, 0.17 h)	87.1° 13:05	11.51	93%	112.2°
2037-12-20 Sun	14	—	unknown	18:35–18:45 (good, 0.17 h)	87.1° 13:00	11.51	97%	115.9°
2037-12-21 Mon	12	—	unknown	18:35–18:45 (good, 0.17 h)	87.1° 13:00	11.51	100%	118.3°
2037-12-22 Tue	12	—	unknown	18:35–18:40 (good, 0.08 h)	87.1° 12:55	11.51	100%	119.1°
2037-12-23 Wed	10	—	unknown	18:05–19:20 (marginal, 1.25 h)	87.1° 12:50	11.5	98%	118.2°
2037-12-24 Thu	11	—	unknown	18:40–18:45 (good, 0.08 h)	87.1° 12:45	11.5	94%	115.7°
2037-12-25 Fri	11	—	unknown	18:05–19:15 (marginal, 1.17 h)	87.1° 12:40	11.5	87%	111.5°
2037-12-26 Sat	10	—	unknown	18:40–19:10 (marginal, 0.5 h)	87.1° 12:40	11.49	78%	106.2°
2037-12-27 Sun	9	—	unknown	18:40–19:05 (marginal, 0.42 h)	87.1° 12:35	11.49	68%	100.0°
2037-12-28 Mon	9	—	unknown	18:40–19:00 (marginal, 0.33 h)	87.1° 12:30	11.48	57%	93.3°
2037-12-29 Tue	8	—	unknown	18:40–18:55 (marginal, 0.25 h)	87.1° 12:25	11.48	46%	86.4°
2037-12-30 Wed	8	—	unknown	05:50–06:10 (marginal, 0.33 h)	87.1° 12:20	11.47	35%	79.7°
2037-12-31 Thu	8	—	unknown	05:50–06:10 (marginal, 0.33 h)	87.1° 12:20	11.46	24%	73.6°
2038-01-01 Fri	8	—	unknown	05:45–06:10 (marginal, 0.42 h)	87.1° 12:15	11.45	15%	68.3°
2038-01-02 Sat	10	—	unknown	05:40–06:10 (marginal, 0.5 h)	87.1° 12:10	11.44	8%	64.2°
2038-01-03 Sun	11	—	unknown	05:35–06:45 (marginal, 1.17 h)	87.1° 12:05	11.43	3%	61.7°
2038-01-04 Mon	11	—	unknown	06:05–06:10 (good, 0.08 h)	87.1° 12:00	11.41	0%	60.9°
2038-01-05 Tue	12	—	unknown	06:00–06:10 (good, 0.17 h)	87.1° 11:55	11.4	0%	61.9°
2038-01-06 Wed	13	—	unknown	05:55–06:10 (good, 0.25 h)	87.1° 11:50	11.39	2%	64.4°
2038-01-07 Thu	14	—	unknown	05:55–06:10 (good, 0.25 h)	87.1° 11:45	11.37	6%	68.2°
2038-01-08 Fri	16	—	unknown	05:50–06:10 (good, 0.33 h)	87.1° 11:45	11.36	12%	72.9°
2038-01-09 Sat	17	—	unknown	05:45–06:10 (good, 0.42 h)	87.1° 11:40	11.34	18%	78.1°
2038-01-10 Sun	18	—	unknown	05:40–06:10 (good, 0.5 h)	87.1° 11:35	11.32	26%	83.7°
2038-01-11 Mon	20	—	unknown	05:35–06:10 (good, 0.58 h)	87.1° 11:30	11.3	35%	89.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-12-13&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.