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: 05-07 (100), 05-08 (100), 05-09 (100), 05-10 (100), 05-11 (100) — by astronomy; check the weather when the night is within four days.

2027-05-07astronomy score per night — click a bar for that night2027-06-05

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-05-07 Fri	100	—	unknown	23:00–04:20 (good, 5.33 h)	87.1° 04:55	6.03	3%	107.3°
2027-05-08 Sat	100	—	unknown	23:00–04:20 (good, 5.33 h)	87.1° 04:50	5.98	8%	111.6°
2027-05-09 Sun	100	—	unknown	22:55–04:15 (good, 5.33 h)	87.1° 04:50	5.92	16%	114.6°
2027-05-10 Mon	100	—	unknown	22:55–04:15 (good, 5.33 h)	87.1° 04:45	5.86	25%	116.0°
2027-05-11 Tue	100	—	unknown	22:50–04:15 (good, 5.42 h)	87.1° 04:40	5.81	36%	115.6°
2027-05-12 Wed	100	—	unknown	22:50–04:10 (good, 5.33 h)	87.1° 04:35	5.75	47%	113.6°
2027-05-13 Thu	100	—	unknown	22:50–04:10 (good, 5.33 h)	87.1° 04:35	5.7	58%	110.2°
2027-05-14 Fri	100	—	unknown	22:50–04:10 (good, 5.33 h)	87.1° 04:30	5.64	69%	105.7°
2027-05-15 Sat	100	—	unknown	22:55–04:05 (good, 5.17 h)	87.1° 04:25	5.59	79%	100.4°
2027-05-16 Sun	100	—	unknown	22:55–04:05 (good, 5.17 h)	87.1° 04:20	5.54	87%	94.7°
2027-05-17 Mon	81	—	unknown	23:15–04:05 (good, 4.83 h)	87.1° 04:15	5.48	93%	88.9°
2027-05-18 Tue	77	—	unknown	23:40–04:05 (good, 4.42 h)	87.1° 04:15	5.43	97%	83.2°
2027-05-19 Wed	73	—	unknown	23:55–04:00 (good, 4.08 h)	87.1° 04:10	5.38	100%	77.9°
2027-05-20 Thu	68	—	unknown	23:55–04:00 (good, 4.08 h)	87.1° 04:05	5.33	100%	73.2°
2027-05-21 Fri	66	—	unknown	23:15–04:00 (good, 4.75 h)	87.1° 04:00	5.28	98%	69.3°
2027-05-22 Sat	84	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:55	5.23	94%	66.3°
2027-05-23 Sun	90	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:55	5.19	89%	64.5°
2027-05-24 Mon	94	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:50	5.14	82%	63.8°
2027-05-25 Tue	98	—	unknown	22:50–03:55 (good, 5.08 h)	87.1° 03:45	5.09	74%	64.3°
2027-05-26 Wed	100	—	unknown	22:50–03:50 (good, 5.0 h)	87.1° 03:40	5.05	66%	66.0°
2027-05-27 Thu	100	—	unknown	22:50–03:50 (good, 5.0 h)	87.1° 03:40	5.0	56%	68.8°
2027-05-28 Fri	100	—	unknown	22:50–03:50 (good, 5.0 h)	87.1° 03:35	4.96	47%	72.5°
2027-05-29 Sat	100	—	unknown	22:55–03:50 (good, 4.92 h)	87.1° 03:30	4.92	37%	77.0°
2027-05-30 Sun	100	—	unknown	22:55–03:45 (good, 4.83 h)	87.1° 03:25	4.88	27%	82.1°
2027-05-31 Mon	100	—	unknown	22:55–03:45 (good, 4.83 h)	87.1° 03:20	4.84	19%	87.8°
2027-06-01 Tue	100	—	unknown	22:55–03:45 (good, 4.83 h)	87.1° 03:20	4.8	11%	93.7°
2027-06-02 Wed	100	—	unknown	23:00–03:45 (good, 4.75 h)	87.1° 03:15	4.77	5%	99.6°
2027-06-03 Thu	100	—	unknown	23:00–03:45 (good, 4.75 h)	87.1° 03:10	4.73	1%	105.3°
2027-06-04 Fri	100	—	unknown	23:00–03:45 (good, 4.75 h)	87.1° 03:05	4.7	0%	110.1°
2027-06-05 Sat	100	—	unknown	23:00–03:40 (good, 4.67 h)	87.1° 03:00	4.67	2%	113.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-05-07&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.