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: 03-05 (65), 03-06 (62), 03-07 (60), 03-08 (58), 03-09 (56) — by astronomy; check the weather when the night is within four days.

2040-03-05astronomy score per night — click a bar for that night2040-04-03

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2040-03-05 Mon	65	—	unknown	19:50–22:25 (good, 2.58 h)	72.5° 17:15	9.43	54%	168.0°
2040-03-06 Tue	62	—	unknown	19:55–22:20 (good, 2.42 h)	72.5° 17:10	9.39	43%	154.4°
2040-03-07 Wed	60	—	unknown	19:55–22:15 (good, 2.33 h)	72.5° 17:05	9.34	32%	140.4°
2040-03-08 Thu	58	—	unknown	19:55–22:15 (good, 2.33 h)	72.5° 17:00	9.29	22%	126.1°
2040-03-09 Fri	56	—	unknown	19:55–22:10 (good, 2.25 h)	72.5° 17:00	9.24	13%	111.8°
2040-03-10 Sat	54	—	unknown	19:55–22:05 (good, 2.17 h)	72.5° 16:55	9.19	6%	97.4°
2040-03-11 Sun	51	—	unknown	20:00–22:00 (good, 2.0 h)	72.5° 16:50	9.15	2%	83.2°
2040-03-12 Mon	50	—	unknown	20:00–21:55 (good, 1.92 h)	72.5° 16:45	9.1	0%	69.1°
2040-03-13 Tue	47	—	unknown	20:00–21:55 (good, 1.92 h)	72.5° 16:40	9.05	1%	55.3°
2040-03-14 Wed	45	—	unknown	20:00–21:50 (good, 1.83 h)	72.5° 16:40	9.0	4%	41.9°
2040-03-15 Thu	40	—	unknown	20:05–21:45 (good, 1.67 h)	72.5° 16:35	8.95	10%	28.8°
2040-03-16 Fri	34	—	unknown	20:05–21:35 (good, 1.5 h)	72.5° 16:30	8.9	16%	16.3°
2040-03-17 Sat	28	—	unknown	20:05–21:25 (good, 1.33 h)	72.5° 16:25	8.84	24%	5.7°
2040-03-18 Sun	23	—	unknown	20:05–21:15 (good, 1.17 h)	72.5° 16:25	8.79	33%	10.1°
2040-03-19 Mon	17	—	unknown	19:35–21:55 (marginal, 2.33 h)	72.5° 16:20	8.74	42%	21.5°
2040-03-20 Tue	13	—	unknown	20:10–21:45 (marginal, 1.58 h)	72.5° 16:15	8.69	52%	33.2°
2040-03-21 Wed	11	—	unknown	20:10–21:35 (marginal, 1.42 h)	72.5° 16:10	8.64	61%	44.9°
2040-03-22 Thu	10	—	unknown	20:10–21:30 (marginal, 1.33 h)	72.5° 16:05	8.59	70%	56.7°
2040-03-23 Fri	10	—	unknown	20:15–21:30 (marginal, 1.25 h)	72.5° 16:05	8.53	78%	68.7°
2040-03-24 Sat	11	—	unknown	20:15–21:30 (marginal, 1.25 h)	72.5° 16:00	8.48	86%	80.8°
2040-03-25 Sun	13	—	unknown	21:15–22:30 (marginal, 1.25 h)	72.5° 16:55	8.43	92%	93.2°
2040-03-26 Mon	14	—	unknown	21:15–21:40 (good, 0.42 h)	72.5° 16:50	8.37	97%	105.9°
2040-03-27 Tue	16	—	unknown	21:20–21:45 (good, 0.42 h)	72.5° 16:45	8.32	99%	118.9°
2040-03-28 Wed	15	—	unknown	21:20–21:45 (good, 0.42 h)	72.5° 16:45	8.27	100%	132.2°
2040-03-29 Thu	15	—	unknown	21:20–21:40 (good, 0.33 h)	72.5° 16:40	8.21	98%	145.7°
2040-03-30 Fri	15	—	unknown	21:25–21:45 (good, 0.33 h)	72.5° 16:35	8.16	94%	159.3°
2040-03-31 Sat	13	—	unknown	21:25–21:45 (good, 0.33 h)	72.5° 16:30	8.1	87%	172.2°
2040-04-01 Sun	11	—	unknown	21:25–21:40 (good, 0.25 h)	72.5° 16:30	8.05	79%	171.0°
2040-04-02 Mon	10	—	unknown	21:25–21:35 (good, 0.17 h)	72.5° 16:25	7.99	68%	157.6°
2040-04-03 Tue	8	—	unknown	20:55–22:00 (marginal, 1.08 h)	72.5° 16:20	7.94	57%	143.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-03-05&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.