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 Andromeda Galaxy: 12-27 (100), 12-28 (100), 12-29 (100), 12-30 (100), 12-31 (100) — by astronomy; check the weather when the night is within four days.

2037-12-27astronomy score per night — click a bar for that night2038-01-25

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-12-27 Sun	100	—	unknown	18:40–00:40 (good, 6.0 h)	89.8° 18:40	11.49	68%	124.5°
2037-12-28 Mon	100	—	unknown	18:40–00:40 (good, 6.0 h)	89.7° 18:35	11.48	57%	132.9°
2037-12-29 Tue	100	—	unknown	18:40–00:40 (good, 6.0 h)	89.6° 18:30	11.48	46%	139.0°
2037-12-30 Wed	100	—	unknown	18:40–00:35 (good, 5.92 h)	89.6° 18:30	11.47	35%	141.4°
2037-12-31 Thu	100	—	unknown	18:45–00:35 (good, 5.83 h)	89.7° 18:25	11.46	24%	139.6°
2038-01-01 Fri	100	—	unknown	18:45–00:30 (good, 5.75 h)	89.8° 18:20	11.45	15%	134.2°
2038-01-02 Sat	100	—	unknown	18:45–00:25 (good, 5.67 h)	89.7° 18:15	11.44	8%	126.2°
2038-01-03 Sun	100	—	unknown	18:45–00:20 (good, 5.58 h)	89.5° 18:10	11.43	3%	116.8°
2038-01-04 Mon	100	—	unknown	18:45–00:15 (good, 5.5 h)	89.6° 18:10	11.41	0%	106.8°
2038-01-05 Tue	100	—	unknown	18:45–00:15 (good, 5.5 h)	89.8° 18:05	11.4	0%	96.5°
2038-01-06 Wed	100	—	unknown	18:50–00:10 (good, 5.33 h)	89.8° 18:00	11.39	2%	86.3°
2038-01-07 Thu	100	—	unknown	18:50–00:05 (good, 5.25 h)	89.6° 17:55	11.37	6%	76.4°
2038-01-08 Fri	100	—	unknown	18:50–00:00 (good, 5.17 h)	89.5° 17:55	11.36	12%	67.0°
2038-01-09 Sat	96	—	unknown	18:50–00:00 (good, 5.17 h)	89.7° 17:50	11.34	18%	58.3°
2038-01-10 Sun	89	—	unknown	18:50–23:55 (good, 5.08 h)	89.8° 17:45	11.32	26%	50.6°
2038-01-11 Mon	82	—	unknown	18:50–23:50 (good, 5.0 h)	89.7° 17:40	11.3	35%	44.3°
2038-01-12 Tue	72	—	unknown	18:55–23:25 (good, 4.5 h)	89.6° 17:35	11.28	44%	40.1°
2038-01-13 Wed	56	—	unknown	18:55–22:30 (good, 3.58 h)	89.6° 17:35	11.27	54%	38.6°
2038-01-14 Thu	43	—	unknown	18:55–00:05 (marginal, 5.17 h)	89.7° 17:30	11.24	63%	40.1°
2038-01-15 Fri	35	—	unknown	18:55–23:50 (marginal, 4.92 h)	89.8° 17:25	11.22	72%	44.4°
2038-01-16 Sat	32	—	unknown	18:55–23:40 (marginal, 4.75 h)	89.7° 17:20	11.2	81%	51.0°
2038-01-17 Sun	32	—	unknown	19:00–23:30 (marginal, 4.5 h)	89.5° 17:15	11.18	88%	59.2°
2038-01-18 Mon	36	—	unknown	19:00–23:25 (marginal, 4.42 h)	89.6° 17:15	11.15	94%	68.7°
2038-01-19 Tue	45	—	unknown	19:00–20:15 (good, 1.25 h)	89.8° 17:10	11.13	98%	78.9°
2038-01-20 Wed	56	—	unknown	19:00–21:20 (good, 2.33 h)	89.8° 17:05	11.11	100%	89.7°
2038-01-21 Thu	70	—	unknown	19:00–22:30 (good, 3.5 h)	89.6° 17:00	11.08	99%	100.7°
2038-01-22 Fri	82	—	unknown	19:05–22:45 (good, 3.67 h)	89.5° 17:00	11.05	96%	111.6°
2038-01-23 Sat	98	—	unknown	19:05–22:50 (good, 3.75 h)	89.7° 16:55	11.03	90%	122.0°
2038-01-24 Sun	98	—	unknown	19:05–22:50 (good, 3.75 h)	89.8° 16:50	11.0	82%	131.0°
2038-01-25 Mon	99	—	unknown	19:05–22:50 (good, 3.75 h)	89.7° 16:45	10.97	72%	137.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-12-27&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.