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: 02-17 (100), 02-18 (100), 02-19 (99), 02-20 (97), 02-21 (95) — by astronomy; check the weather when the night is within four days.

2042-02-17astronomy score per night — click a bar for that night2042-03-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-02-17 Mon	100	—	unknown	19:30–23:30 (good, 4.0 h)	72.5° 18:20	10.16	8%	123.4°
2042-02-18 Tue	100	—	unknown	19:35–23:25 (good, 3.83 h)	72.5° 18:15	10.12	3%	108.9°
2042-02-19 Wed	99	—	unknown	19:35–23:20 (good, 3.75 h)	72.5° 18:10	10.08	0%	94.0°
2042-02-20 Thu	97	—	unknown	19:35–23:20 (good, 3.75 h)	72.5° 18:05	10.04	1%	78.9°
2042-02-21 Fri	95	—	unknown	19:35–23:15 (good, 3.67 h)	72.5° 18:05	9.99	4%	63.7°
2042-02-22 Sat	88	—	unknown	19:40–23:10 (good, 3.5 h)	72.5° 18:00	9.95	10%	48.7°
2042-02-23 Sun	76	—	unknown	19:40–23:05 (good, 3.42 h)	72.5° 17:55	9.91	18%	33.9°
2042-02-24 Mon	61	—	unknown	19:40–22:50 (good, 3.17 h)	72.5° 17:50	9.86	28%	19.5°
2042-02-25 Tue	47	—	unknown	19:40–22:35 (good, 2.92 h)	72.5° 17:45	9.82	39%	5.7°
2042-02-26 Wed	34	—	unknown	19:45–20:35 (good, 0.83 h)	72.5° 17:45	9.78	50%	8.2°
2042-02-27 Thu	24	—	unknown	19:45–23:05 (marginal, 3.33 h)	72.5° 17:40	9.73	60%	21.4°
2042-02-28 Fri	18	—	unknown	19:45–22:50 (marginal, 3.08 h)	72.5° 17:35	9.69	70%	34.3°
2042-03-01 Sat	18	—	unknown	19:45–22:40 (marginal, 2.92 h)	72.5° 17:30	9.64	79%	46.9°
2042-03-02 Sun	20	—	unknown	19:45–22:40 (marginal, 2.92 h)	72.5° 17:30	9.6	86%	59.3°
2042-03-03 Mon	23	—	unknown	19:50–22:40 (marginal, 2.83 h)	72.5° 17:25	9.55	92%	71.5°
2042-03-04 Tue	30	—	unknown	19:50–20:25 (good, 0.58 h)	72.5° 17:20	9.5	97%	83.6°
2042-03-05 Wed	36	—	unknown	19:50–21:30 (good, 1.67 h)	72.5° 17:15	9.46	99%	95.6°
2042-03-06 Thu	44	—	unknown	19:50–22:00 (good, 2.17 h)	72.5° 17:10	9.41	100%	107.5°
2042-03-07 Fri	49	—	unknown	19:55–22:05 (good, 2.17 h)	72.5° 17:10	9.36	99%	119.3°
2042-03-08 Sat	55	—	unknown	19:55–22:05 (good, 2.17 h)	72.5° 17:05	9.31	96%	131.1°
2042-03-09 Sun	55	—	unknown	19:55–22:05 (good, 2.17 h)	72.5° 17:00	9.27	92%	143.0°
2042-03-10 Mon	55	—	unknown	19:55–22:05 (good, 2.17 h)	72.5° 16:55	9.22	86%	154.9°
2042-03-11 Tue	52	—	unknown	20:00–22:05 (good, 2.08 h)	72.5° 16:50	9.17	78%	166.9°
2042-03-12 Wed	50	—	unknown	20:00–22:00 (good, 2.0 h)	72.5° 16:50	9.12	70%	178.4°
2042-03-13 Thu	48	—	unknown	20:00–21:55 (good, 1.92 h)	72.5° 16:45	9.07	60%	168.5°
2042-03-14 Fri	47	—	unknown	20:00–21:50 (good, 1.83 h)	72.5° 16:40	9.02	50%	155.8°
2042-03-15 Sat	43	—	unknown	20:05–21:50 (good, 1.75 h)	72.5° 16:35	8.97	40%	142.8°
2042-03-16 Sun	42	—	unknown	20:05–21:45 (good, 1.67 h)	72.5° 16:35	8.92	30%	129.3°
2042-03-17 Mon	40	—	unknown	20:05–21:40 (good, 1.58 h)	72.5° 16:30	8.87	20%	115.3°
2042-03-18 Tue	38	—	unknown	20:05–21:35 (good, 1.5 h)	72.5° 16:25	8.82	11%	100.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-02-17&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.