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: 07-13 (100), 07-14 (100), 07-23 (100), 07-24 (100), 07-25 (100) — by astronomy; check the weather when the night is within four days.

2027-07-13astronomy score per night — click a bar for that night2027-08-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-07-13 Tue	100	—	unknown	23:00–03:55 (good, 4.92 h)	87.1° 00:35	4.9	80%	75.6°
2027-07-14 Wed	100	—	unknown	23:00–04:00 (good, 5.0 h)	87.1° 00:30	4.95	88%	71.3°
2027-07-15 Thu	97	—	unknown	23:00–04:00 (good, 5.0 h)	87.1° 00:25	4.99	93%	67.8°
2027-07-16 Fri	68	—	unknown	23:00–04:00 (good, 5.0 h)	87.1° 00:20	5.03	97%	65.3°
2027-07-17 Sat	60	—	unknown	23:00–04:00 (good, 5.0 h)	87.1° 00:15	5.07	100%	63.9°
2027-07-18 Sun	60	—	unknown	22:55–01:05 (good, 2.17 h)	87.1° 00:15	5.12	100%	63.7°
2027-07-19 Mon	62	—	unknown	22:55–01:20 (good, 2.42 h)	87.1° 00:10	5.17	98%	64.8°
2027-07-20 Tue	68	—	unknown	22:55–02:30 (good, 3.58 h)	87.1° 00:05	5.21	95%	66.9°
2027-07-21 Wed	74	—	unknown	22:50–03:05 (good, 4.25 h)	87.1° 00:00	5.26	91%	70.1°
2027-07-22 Thu	79	—	unknown	22:50–03:45 (good, 4.92 h)	87.1° 23:55	5.31	84%	74.1°
2027-07-23 Fri	100	—	unknown	22:50–04:10 (good, 5.33 h)	87.1° 23:55	5.36	77%	78.7°
2027-07-24 Sat	100	—	unknown	22:50–04:15 (good, 5.42 h)	87.1° 23:50	5.41	68%	83.9°
2027-07-25 Sun	100	—	unknown	22:45–04:15 (good, 5.5 h)	87.1° 23:45	5.46	58%	89.4°
2027-07-26 Mon	100	—	unknown	22:45–04:15 (good, 5.5 h)	87.1° 23:40	5.51	48%	95.1°
2027-07-27 Tue	100	—	unknown	22:45–04:15 (good, 5.5 h)	87.1° 23:40	5.56	37%	100.8°
2027-07-28 Wed	100	—	unknown	22:40–04:20 (good, 5.67 h)	87.1° 23:35	5.62	27%	106.1°
2027-07-29 Thu	100	—	unknown	22:40–04:20 (good, 5.67 h)	87.1° 23:30	5.67	17%	110.7°
2027-07-30 Fri	100	—	unknown	22:40–04:20 (good, 5.67 h)	87.1° 23:25	5.72	9%	114.2°
2027-07-31 Sat	100	—	unknown	22:35–04:25 (good, 5.83 h)	87.1° 23:20	5.78	3%	116.1°
2027-08-01 Sun	100	—	unknown	22:35–04:25 (good, 5.83 h)	87.1° 23:20	5.83	0%	116.1°
2027-08-02 Mon	100	—	unknown	22:35–04:25 (good, 5.83 h)	87.1° 23:15	5.89	0%	114.1°
2027-08-03 Tue	100	—	unknown	22:30–04:30 (good, 6.0 h)	87.1° 23:10	5.94	4%	110.4°
2027-08-04 Wed	100	—	unknown	22:30–04:30 (good, 6.0 h)	87.1° 23:05	6.0	9%	105.5°
2027-08-05 Thu	100	—	unknown	22:30–04:30 (good, 6.0 h)	87.1° 23:00	6.06	17%	99.8°
2027-08-06 Fri	100	—	unknown	22:25–04:35 (good, 6.17 h)	87.1° 23:00	6.11	26%	93.8°
2027-08-07 Sat	100	—	unknown	22:25–04:35 (good, 6.17 h)	87.1° 22:55	6.17	37%	87.8°
2027-08-08 Sun	100	—	unknown	22:25–04:35 (good, 6.17 h)	87.1° 22:50	6.23	47%	82.1°
2027-08-09 Mon	100	—	unknown	22:20–04:40 (good, 6.33 h)	87.1° 22:45	6.28	57%	76.9°
2027-08-10 Tue	100	—	unknown	22:20–04:40 (good, 6.33 h)	87.1° 22:45	6.34	67%	72.3°
2027-08-11 Wed	99	—	unknown	22:15–04:40 (good, 6.42 h)	87.1° 22:40	6.4	76%	68.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-07-13&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.