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: 01-16 (100), 01-17 (100), 01-18 (100), 01-19 (100), 01-20 (100) — by astronomy; check the weather when the night is within four days.

2042-01-16astronomy score per night — click a bar for that night2042-02-14

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-01-16 Thu	100	—	unknown	18:55–01:35 (good, 6.67 h)	72.5° 20:25	11.2	27%	174.4°
2042-01-17 Fri	100	—	unknown	19:00–01:30 (good, 6.5 h)	72.5° 20:20	11.18	18%	172.3°
2042-01-18 Sat	100	—	unknown	19:00–01:30 (good, 6.5 h)	72.5° 20:15	11.15	11%	159.1°
2042-01-19 Sun	100	—	unknown	19:00–01:25 (good, 6.42 h)	72.5° 20:15	11.13	5%	145.4°
2042-01-20 Mon	100	—	unknown	19:00–01:20 (good, 6.33 h)	72.5° 20:10	11.1	1%	131.3°
2042-01-21 Tue	100	—	unknown	19:00–01:15 (good, 6.25 h)	72.5° 20:05	11.08	0%	116.9°
2042-01-22 Wed	100	—	unknown	19:05–01:10 (good, 6.08 h)	72.5° 20:00	11.05	2%	102.2°
2042-01-23 Thu	100	—	unknown	19:05–01:10 (good, 6.08 h)	72.5° 19:55	11.03	6%	87.5°
2042-01-24 Fri	100	—	unknown	19:05–01:05 (good, 6.0 h)	72.5° 19:55	11.0	13%	72.7°
2042-01-25 Sat	99	—	unknown	19:05–01:00 (good, 5.92 h)	72.5° 19:50	10.97	22%	58.1°
2042-01-26 Sun	90	—	unknown	19:10–00:55 (good, 5.75 h)	72.5° 19:45	10.94	32%	43.7°
2042-01-27 Mon	78	—	unknown	19:10–00:50 (good, 5.67 h)	72.5° 19:40	10.91	43%	29.5°
2042-01-28 Tue	60	—	unknown	20:05–23:45 (good, 3.67 h)	72.5° 19:35	10.88	55%	15.7°
2042-01-29 Wed	41	—	unknown	19:10–01:05 (marginal, 5.92 h)	72.5° 19:35	10.85	65%	2.7°
2042-01-30 Thu	27	—	unknown	19:10–00:45 (marginal, 5.58 h)	72.5° 19:30	10.82	75%	11.4°
2042-01-31 Fri	19	—	unknown	19:15–00:20 (marginal, 5.08 h)	72.5° 19:25	10.79	83%	24.4°
2042-02-01 Sat	19	—	unknown	19:15–23:05 (marginal, 3.83 h)	72.5° 19:20	10.75	90%	37.2°
2042-02-02 Sun	26	—	unknown	19:15–00:05 (marginal, 4.83 h)	72.5° 19:20	10.72	95%	49.8°
2042-02-03 Mon	37	—	unknown	19:15–00:15 (marginal, 5.0 h)	72.5° 19:15	10.69	98%	62.3°
2042-02-04 Tue	51	—	unknown	19:20–21:00 (good, 1.67 h)	72.5° 19:10	10.65	100%	74.6°
2042-02-05 Wed	68	—	unknown	19:20–22:25 (good, 3.08 h)	72.5° 19:05	10.62	99%	86.8°
2042-02-06 Thu	84	—	unknown	19:20–23:40 (good, 4.33 h)	72.5° 19:00	10.58	97%	98.8°
2042-02-07 Fri	100	—	unknown	19:20–23:50 (good, 4.5 h)	72.5° 19:00	10.55	93%	110.7°
2042-02-08 Sat	100	—	unknown	19:20–23:55 (good, 4.58 h)	72.5° 18:55	10.51	87%	122.5°
2042-02-09 Sun	100	—	unknown	19:25–23:55 (good, 4.5 h)	72.5° 18:50	10.47	80%	134.4°
2042-02-10 Mon	100	—	unknown	19:25–23:50 (good, 4.42 h)	72.5° 18:45	10.44	72%	146.2°
2042-02-11 Tue	100	—	unknown	19:25–23:55 (good, 4.5 h)	72.5° 18:40	10.4	63%	158.2°
2042-02-12 Wed	100	—	unknown	19:25–23:50 (good, 4.42 h)	72.5° 18:40	10.36	54%	170.2°
2042-02-13 Thu	100	—	unknown	19:30–23:45 (good, 4.25 h)	72.5° 18:35	10.32	44%	176.8°
2042-02-14 Fri	100	—	unknown	19:30–23:40 (good, 4.17 h)	72.5° 18:30	10.28	34%	164.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-01-16&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.