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: 12-07 (46), 12-08 (44), 12-09 (40), 12-10 (36), 12-11 (31) — by astronomy; check the weather when the night is within four days.

2037-12-07astronomy score per night — click a bar for that night2038-01-05

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-12-07 Mon	46	—	unknown	18:35–20:25 (good, 1.83 h)	71.1° 15:15	11.42	1%	54.1°
2037-12-08 Tue	44	—	unknown	18:35–20:20 (good, 1.75 h)	71.1° 15:15	11.44	5%	48.0°
2037-12-09 Wed	40	—	unknown	18:35–20:15 (good, 1.67 h)	71.1° 15:10	11.45	10%	44.4°
2037-12-10 Thu	36	—	unknown	18:35–20:05 (good, 1.5 h)	71.1° 15:05	11.46	17%	43.8°
2037-12-11 Fri	31	—	unknown	18:35–20:00 (good, 1.42 h)	71.1° 15:00	11.47	25%	46.1°
2037-12-12 Sat	27	—	unknown	18:35–19:50 (good, 1.25 h)	71.1° 14:55	11.47	34%	50.6°
2037-12-13 Sun	23	—	unknown	18:35–19:40 (good, 1.08 h)	71.1° 14:55	11.48	44%	56.8°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-12-07&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.