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 HD 189733: 12-14 (20), 12-20 (20), 12-24 (20), 12-21 (19), 12-22 (19) — by astronomy; check the weather when the night is within four days.

2037-12-14astronomy score per night — click a bar for that night2038-01-12

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-12-14 Mon	20	—	unknown	18:35–19:30 (good, 0.92 h)	71.1° 14:50	11.49	53%	64.0°
2037-12-15 Tue	18	—	unknown	18:35–19:10 (good, 0.58 h)	71.1° 14:45	11.49	62%	71.9°
2037-12-16 Wed	17	—	unknown	18:35–19:00 (good, 0.42 h)	71.1° 14:40	11.5	71%	80.2°
2037-12-17 Thu	17	—	unknown	18:35–19:05 (good, 0.5 h)	71.1° 14:35	11.5	79%	88.8°
2037-12-18 Fri	17	—	unknown	18:35–19:15 (good, 0.67 h)	71.1° 14:35	11.5	87%	97.6°
2037-12-19 Sat	18	—	unknown	18:35–19:15 (good, 0.67 h)	71.1° 14:30	11.51	93%	106.3°
2037-12-20 Sun	20	—	unknown	18:35–19:15 (good, 0.67 h)	71.1° 14:25	11.51	97%	114.9°
2037-12-21 Mon	19	—	unknown	18:35–19:15 (good, 0.67 h)	71.1° 14:20	11.51	100%	122.8°
2037-12-22 Tue	19	—	unknown	18:35–19:15 (good, 0.67 h)	71.1° 14:20	11.51	100%	129.6°
2037-12-23 Wed	17	—	unknown	18:40–19:10 (good, 0.5 h)	71.1° 14:15	11.5	98%	134.4°
2037-12-24 Thu	20	—	unknown	18:40–19:10 (good, 0.5 h)	71.1° 14:10	11.5	94%	136.3°
2037-12-25 Fri	19	—	unknown	18:40–19:10 (good, 0.5 h)	71.1° 14:05	11.5	87%	134.8°
2037-12-26 Sat	17	—	unknown	18:40–19:10 (good, 0.5 h)	71.1° 14:00	11.49	78%	130.2°
2037-12-27 Sun	15	—	unknown	18:40–19:05 (good, 0.42 h)	71.1° 14:00	11.49	68%	123.2°
2037-12-28 Mon	14	—	unknown	18:40–19:00 (good, 0.33 h)	71.1° 13:55	11.48	57%	114.5°
2037-12-29 Tue	12	—	unknown	18:40–18:55 (good, 0.25 h)	71.1° 13:50	11.48	46%	105.0°
2037-12-30 Wed	11	—	unknown	18:40–18:55 (good, 0.25 h)	71.1° 13:45	11.47	35%	94.9°
2037-12-31 Thu	8	—	unknown	18:45–18:50 (good, 0.08 h)	71.1° 13:40	11.46	24%	84.7°
2038-01-01 Fri	7	—	unknown	18:10–19:10 (marginal, 1.0 h)	71.1° 13:40	11.45	15%	74.7°
2038-01-02 Sat	7	—	unknown	18:45–19:10 (marginal, 0.42 h)	71.1° 13:35	11.44	8%	65.3°
2038-01-03 Sun	6	—	unknown	18:45–19:05 (marginal, 0.33 h)	71.1° 13:30	11.43	3%	56.9°
2038-01-04 Mon	4	—	unknown	18:10–18:35 (marginal, 0.42 h)	71.1° 13:25	11.41	0%	50.0°
2038-01-05 Tue	3	—	unknown	18:15–18:30 (marginal, 0.25 h)	71.1° 13:25	11.4	0%	45.4°
2038-01-06 Wed	2	—	unknown	18:15–18:25 (marginal, 0.17 h)	71.1° 13:20	11.39	2%	43.7°
2038-01-07 Thu	2	—	unknown	18:15–18:20 (marginal, 0.08 h)	71.1° 13:15	11.37	6%	45.0°
2038-01-08 Fri	1	—	unknown	—	71.1° 13:10	11.36	12%	48.8°
2038-01-09 Sat	1	—	unknown	—	71.1° 13:05	11.34	18%	54.6°
2038-01-10 Sun	1	—	unknown	—	71.1° 13:05	11.32	26%	61.5°
2038-01-11 Mon	0	—	unknown	—	71.1° 13:00	11.3	35%	69.2°
2038-01-12 Tue	0	—	unknown	—	71.1° 12:55	11.28	44%	77.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-12-14&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.