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: 12-15 (27), 12-16 (23), 12-17 (19), 12-18 (17), 12-23 (16) — by astronomy; check the weather when the night is within four days.

2034-12-15astronomy score per night — click a bar for that night2035-01-13

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2034-12-15 Fri	27	—	unknown	18:35–19:45 (good, 1.17 h)	71.1° 14:45	11.49	22%	41.2°
2034-12-16 Sat	23	—	unknown	18:35–19:35 (good, 1.0 h)	71.1° 14:40	11.5	31%	46.4°
2034-12-17 Sun	19	—	unknown	18:35–19:25 (good, 0.83 h)	71.1° 14:40	11.5	41%	53.8°
2034-12-18 Mon	17	—	unknown	18:35–19:15 (good, 0.67 h)	71.1° 14:35	11.5	52%	62.7°
2034-12-19 Tue	15	—	unknown	18:35–18:50 (good, 0.25 h)	71.1° 14:30	11.51	63%	72.8°
2034-12-20 Wed	14	—	unknown	18:35–18:45 (good, 0.17 h)	71.1° 14:25	11.51	74%	83.6°
2034-12-21 Thu	14	—	unknown	18:35–19:00 (good, 0.42 h)	71.1° 14:25	11.51	83%	94.9°
2034-12-22 Fri	15	—	unknown	18:35–19:05 (good, 0.5 h)	71.1° 14:20	11.51	91%	106.3°
2034-12-23 Sat	16	—	unknown	18:40–19:10 (good, 0.5 h)	71.1° 14:15	11.51	97%	117.4°
2034-12-24 Sun	16	—	unknown	18:40–19:05 (good, 0.42 h)	71.1° 14:10	11.5	100%	127.5°
2034-12-25 Mon	15	—	unknown	18:40–19:05 (good, 0.42 h)	71.1° 14:05	11.5	99%	135.5°
2034-12-26 Tue	15	—	unknown	18:40–19:00 (good, 0.33 h)	71.1° 14:05	11.5	96%	140.3°
2034-12-27 Wed	16	—	unknown	18:40–19:05 (good, 0.42 h)	71.1° 14:00	11.49	91%	140.7°
2034-12-28 Thu	15	—	unknown	18:40–19:00 (good, 0.33 h)	71.1° 13:55	11.48	83%	137.0°
2034-12-29 Fri	12	—	unknown	18:40–18:55 (good, 0.25 h)	71.1° 13:50	11.48	74%	130.4°
2034-12-30 Sat	11	—	unknown	18:40–18:55 (good, 0.25 h)	71.1° 13:45	11.47	65%	122.2°
2034-12-31 Sun	9	—	unknown	18:45–18:50 (good, 0.08 h)	71.1° 13:45	11.46	55%	113.3°
2035-01-01 Mon	8	—	unknown	18:10–19:15 (marginal, 1.08 h)	71.1° 13:40	11.45	45%	104.1°
2035-01-02 Tue	7	—	unknown	18:45–19:10 (marginal, 0.42 h)	71.1° 13:35	11.44	36%	94.7°
2035-01-03 Wed	6	—	unknown	18:10–18:40 (marginal, 0.5 h)	71.1° 13:30	11.43	27%	85.5°
2035-01-04 Thu	5	—	unknown	18:10–18:35 (marginal, 0.42 h)	71.1° 13:30	11.42	19%	76.3°
2035-01-05 Fri	3	—	unknown	18:15–18:30 (marginal, 0.25 h)	71.1° 13:25	11.4	12%	67.5°
2035-01-06 Sat	3	—	unknown	18:15–18:25 (marginal, 0.17 h)	71.1° 13:20	11.39	7%	59.1°
2035-01-07 Sun	2	—	unknown	18:15–18:20 (marginal, 0.08 h)	71.1° 13:15	11.38	3%	51.5°
2035-01-08 Mon	1	—	unknown	18:15–18:20 (marginal, 0.08 h)	71.1° 13:10	11.36	1%	45.1°
2035-01-09 Tue	1	—	unknown	—	71.1° 13:10	11.34	0%	40.6°
2035-01-10 Wed	1	—	unknown	—	71.1° 13:05	11.33	2%	39.0°
2035-01-11 Thu	1	—	unknown	—	71.1° 13:00	11.31	5%	40.6°
2035-01-12 Fri	0	—	unknown	—	71.1° 12:55	11.29	11%	45.2°
2035-01-13 Sat	0	—	unknown	—	71.1° 12:50	11.27	18%	52.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-12-15&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.