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 Seven Sisters: 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	18:40–02:40 (good, 8.0 h)	72.5° 21:45	11.49	68%	104.6°
2037-12-28 Mon	100	—	unknown	18:40–02:45 (good, 8.08 h)	72.5° 21:40	11.48	57%	118.5°
2037-12-29 Tue	100	—	unknown	18:40–02:40 (good, 8.0 h)	72.5° 21:35	11.48	46%	132.5°
2037-12-30 Wed	100	—	unknown	18:40–02:40 (good, 8.0 h)	72.5° 21:30	11.47	35%	146.2°
2037-12-31 Thu	100	—	unknown	18:45–02:40 (good, 7.92 h)	72.5° 21:25	11.46	24%	159.6°
2038-01-01 Fri	100	—	unknown	18:45–02:35 (good, 7.83 h)	72.5° 21:25	11.45	15%	170.6°
2038-01-02 Sat	100	—	unknown	18:45–02:30 (good, 7.75 h)	72.5° 21:20	11.44	8%	167.7°
2038-01-03 Sun	100	—	unknown	18:45–02:25 (good, 7.67 h)	72.5° 21:15	11.43	3%	155.7°
2038-01-04 Mon	100	—	unknown	18:45–02:25 (good, 7.67 h)	72.5° 21:10	11.41	0%	142.6°
2038-01-05 Tue	100	—	unknown	18:45–02:20 (good, 7.58 h)	72.5° 21:10	11.4	0%	129.5°
2038-01-06 Wed	100	—	unknown	18:50–02:15 (good, 7.42 h)	72.5° 21:05	11.39	2%	116.6°
2038-01-07 Thu	100	—	unknown	18:50–02:10 (good, 7.33 h)	72.5° 21:00	11.37	6%	104.0°
2038-01-08 Fri	100	—	unknown	18:50–02:05 (good, 7.25 h)	72.5° 20:55	11.36	12%	91.6°
2038-01-09 Sat	100	—	unknown	18:50–02:05 (good, 7.25 h)	72.5° 20:50	11.34	18%	79.5°
2038-01-10 Sun	100	—	unknown	18:50–02:00 (good, 7.17 h)	72.5° 20:50	11.32	26%	67.6°
2038-01-11 Mon	97	—	unknown	18:50–01:55 (good, 7.08 h)	72.5° 20:45	11.3	35%	55.9°
2038-01-12 Tue	90	—	unknown	18:55–01:50 (good, 6.92 h)	72.5° 20:40	11.28	44%	44.3°
2038-01-13 Wed	82	—	unknown	18:55–01:45 (good, 6.83 h)	72.5° 20:35	11.27	54%	32.7°
2038-01-14 Thu	60	—	unknown	18:55–02:10 (marginal, 7.25 h)	72.5° 20:30	11.24	63%	21.4°
2038-01-15 Fri	44	—	unknown	18:55–02:00 (marginal, 7.08 h)	72.5° 20:30	11.22	72%	11.2°
2038-01-16 Sat	30	—	unknown	18:55–01:40 (marginal, 6.75 h)	72.5° 20:25	11.2	81%	9.4°
2038-01-17 Sun	22	—	unknown	19:00–01:15 (marginal, 6.25 h)	72.5° 20:20	11.18	88%	19.2°
2038-01-18 Mon	20	—	unknown	19:00–20:55 (marginal, 1.92 h)	72.5° 20:15	11.15	94%	31.5°
2038-01-19 Tue	29	—	unknown	19:00–23:50 (marginal, 4.83 h)	72.5° 20:15	11.13	98%	44.7°
2038-01-20 Wed	45	—	unknown	19:00–01:05 (marginal, 6.08 h)	72.5° 20:10	11.11	100%	58.3°
2038-01-21 Thu	68	—	unknown	19:00–21:30 (good, 2.5 h)	72.5° 20:05	11.08	99%	72.3°
2038-01-22 Fri	81	—	unknown	19:05–23:30 (good, 4.42 h)	72.5° 20:00	11.05	96%	86.5°
2038-01-23 Sat	100	—	unknown	19:05–00:45 (good, 5.67 h)	72.5° 19:55	11.03	90%	100.8°
2038-01-24 Sun	100	—	unknown	19:05–00:50 (good, 5.75 h)	72.5° 19:55	11.0	82%	115.1°
2038-01-25 Mon	100	—	unknown	19:05–00:55 (good, 5.83 h)	72.5° 19:50	10.97	72%	129.3°

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.