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: 05-18 (100), 05-19 (100), 05-20 (100), 05-21 (100), 05-22 (100) — by astronomy; check the weather when the night is within four days.

2044-05-16astronomy score per night — click a bar for that night2044-06-14

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-05-16 Mon	95	—	unknown	22:35–04:05 (good, 5.5 h)	87.1° 04:20	5.49	79%	66.1°
2044-05-17 Tue	99	—	unknown	22:35–04:05 (good, 5.5 h)	87.1° 04:15	5.44	71%	66.6°
2044-05-18 Wed	100	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:10	5.39	62%	68.3°
2044-05-19 Thu	100	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:05	5.34	52%	70.9°
2044-05-20 Fri	100	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:00	5.29	42%	74.5°
2044-05-21 Sat	100	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 04:00	5.24	32%	78.9°
2044-05-22 Sun	100	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:55	5.19	23%	83.9°
2044-05-23 Mon	100	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:50	5.14	14%	89.5°
2044-05-24 Tue	100	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:45	5.1	7%	95.2°
2044-05-25 Wed	100	—	unknown	22:50–03:50 (good, 5.0 h)	87.1° 03:45	5.05	2%	100.8°
2044-05-26 Thu	100	—	unknown	22:50–03:50 (good, 5.0 h)	87.1° 03:40	5.01	0%	106.0°
2044-05-27 Fri	100	—	unknown	22:50–03:50 (good, 5.0 h)	87.1° 03:35	4.97	1%	110.1°
2044-05-28 Sat	100	—	unknown	22:55–03:50 (good, 4.92 h)	87.1° 03:30	4.92	5%	112.9°
2044-05-29 Sun	100	—	unknown	22:55–03:50 (good, 4.92 h)	87.1° 03:25	4.88	11%	114.0°
2044-05-30 Mon	100	—	unknown	22:55–03:45 (good, 4.83 h)	87.1° 03:25	4.85	20%	113.4°
2044-05-31 Tue	100	—	unknown	22:55–03:45 (good, 4.83 h)	87.1° 03:20	4.81	30%	111.3°
2044-06-01 Wed	100	—	unknown	23:00–03:45 (good, 4.75 h)	87.1° 03:15	4.77	41%	108.0°
2044-06-02 Thu	100	—	unknown	23:00–03:45 (good, 4.75 h)	87.1° 03:10	4.74	52%	103.8°
2044-06-03 Fri	100	—	unknown	23:00–03:45 (good, 4.75 h)	87.1° 03:05	4.7	62%	99.0°
2044-06-04 Sat	100	—	unknown	23:00–03:40 (good, 4.67 h)	87.1° 03:05	4.67	72%	94.0°
2044-06-05 Sun	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 03:00	4.64	80%	88.9°
2044-06-06 Mon	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:55	4.62	88%	83.9°
2044-06-07 Tue	78	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:50	4.59	93%	79.2°
2044-06-08 Wed	73	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:45	4.56	97%	75.0°
2044-06-09 Thu	66	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:45	4.54	99%	71.5°
2044-06-10 Fri	62	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:40	4.52	100%	68.7°
2044-06-11 Sat	63	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:35	4.5	98%	66.8°
2044-06-12 Sun	68	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:30	4.48	95%	66.0°
2044-06-13 Mon	98	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:30	4.47	90%	66.2°
2044-06-14 Tue	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:25	4.46	84%	67.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-05-16&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.