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 Vega: 04-17 (100), 04-18 (100), 04-19 (100), 04-20 (100), 04-21 (100) — by astronomy; check the weather when the night is within four days.

2045-04-17astronomy score per night — click a bar for that night2045-05-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-04-17 Mon	100	—	unknown	00:20–04:55 (good, 4.58 h)	87.1° 06:15	7.15	1%	95.5°
2045-04-18 Tue	100	—	unknown	00:15–04:55 (good, 4.67 h)	87.1° 06:10	7.1	3%	100.9°
2045-04-19 Wed	100	—	unknown	00:10–04:55 (good, 4.75 h)	87.1° 06:05	7.04	8%	105.8°
2045-04-20 Thu	100	—	unknown	00:10–04:50 (good, 4.67 h)	87.1° 06:00	6.98	15%	110.0°
2045-04-21 Fri	100	—	unknown	00:05–04:50 (good, 4.75 h)	87.1° 05:55	6.92	24%	113.0°
2045-04-22 Sat	100	—	unknown	00:05–04:50 (good, 4.75 h)	87.1° 05:55	6.86	35%	114.7°
2045-04-23 Sun	100	—	unknown	00:00–04:45 (good, 4.75 h)	87.1° 05:50	6.81	46%	114.8°
2045-04-24 Mon	100	—	unknown	00:00–04:45 (good, 4.75 h)	87.1° 05:45	6.75	57%	113.3°
2045-04-25 Tue	100	—	unknown	00:00–04:40 (good, 4.67 h)	87.1° 05:40	6.69	68%	110.4°
2045-04-26 Wed	100	—	unknown	00:00–04:40 (good, 4.67 h)	87.1° 05:40	6.63	78%	106.2°
2045-04-27 Thu	100	—	unknown	00:05–04:40 (good, 4.58 h)	87.1° 05:35	6.57	87%	101.2°
2045-04-28 Fri	83	—	unknown	00:10–04:35 (good, 4.42 h)	87.1° 05:30	6.51	94%	95.6°
2045-04-29 Sat	78	—	unknown	00:40–04:35 (good, 3.92 h)	87.1° 05:25	6.46	98%	89.8°
2045-04-30 Sun	71	—	unknown	00:55–04:30 (good, 3.58 h)	87.1° 05:20	6.4	100%	84.1°
2045-05-01 Mon	67	—	unknown	01:00–04:30 (good, 3.5 h)	87.1° 05:20	6.34	99%	78.8°
2045-05-02 Tue	65	—	unknown	00:40–04:30 (good, 3.83 h)	87.1° 05:15	6.28	97%	74.1°
2045-05-03 Wed	68	—	unknown	23:45–04:25 (good, 4.67 h)	87.1° 05:10	6.22	92%	70.2°
2045-05-04 Thu	84	—	unknown	23:10–04:25 (good, 5.25 h)	87.1° 05:05	6.17	86%	67.3°
2045-05-05 Fri	90	—	unknown	23:10–04:25 (good, 5.25 h)	87.1° 05:00	6.11	78%	65.5°
2045-05-06 Sat	95	—	unknown	23:05–04:20 (good, 5.25 h)	87.1° 05:00	6.05	70%	64.9°
2045-05-07 Sun	99	—	unknown	23:00–04:20 (good, 5.33 h)	87.1° 04:55	6.0	61%	65.5°
2045-05-08 Mon	100	—	unknown	22:55–04:20 (good, 5.42 h)	87.1° 04:50	5.94	52%	67.1°
2045-05-09 Tue	100	—	unknown	22:50–04:15 (good, 5.42 h)	87.1° 04:45	5.88	42%	69.8°
2045-05-10 Wed	100	—	unknown	22:50–04:15 (good, 5.42 h)	87.1° 04:40	5.83	33%	73.3°
2045-05-11 Thu	100	—	unknown	22:45–04:15 (good, 5.5 h)	87.1° 04:40	5.77	24%	77.6°
2045-05-12 Fri	100	—	unknown	22:40–04:10 (good, 5.5 h)	87.1° 04:35	5.72	16%	82.5°
2045-05-13 Sat	100	—	unknown	22:35–04:10 (good, 5.58 h)	87.1° 04:30	5.66	10%	87.8°
2045-05-14 Sun	100	—	unknown	22:30–04:10 (good, 5.67 h)	87.1° 04:25	5.61	4%	93.4°
2045-05-15 Mon	100	—	unknown	22:35–04:05 (good, 5.5 h)	87.1° 04:25	5.56	1%	99.0°
2045-05-16 Tue	100	—	unknown	22:35–04:05 (good, 5.5 h)	87.1° 04:20	5.5	0%	104.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-04-17&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.