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: 08-29 (100), 08-30 (100), 08-31 (100), 09-01 (100), 09-02 (100) — by astronomy; check the weather when the night is within four days.

2037-08-21astronomy score per night — click a bar for that night2037-09-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-08-21 Fri	82	—	unknown	21:55–03:55 (good, 6.0 h)	87.1° 21:55	7.01	86%	60.6°
2037-08-22 Sat	63	—	unknown	21:55–01:35 (good, 3.67 h)	87.1° 21:55	7.06	92%	62.5°
2037-08-23 Sun	62	—	unknown	21:55–00:45 (good, 2.83 h)	87.1° 21:50	7.12	97%	65.7°
2037-08-24 Mon	64	—	unknown	21:50–00:40 (good, 2.83 h)	87.1° 21:45	7.18	99%	69.9°
2037-08-25 Tue	69	—	unknown	21:50–00:55 (good, 3.08 h)	87.1° 21:40	7.24	100%	74.8°
2037-08-26 Wed	74	—	unknown	21:45–01:20 (good, 3.58 h)	87.1° 21:40	7.29	99%	80.3°
2037-08-27 Thu	79	—	unknown	21:45–01:55 (good, 4.17 h)	87.1° 21:35	7.35	96%	86.0°
2037-08-28 Fri	83	—	unknown	21:45–02:30 (good, 4.75 h)	87.1° 21:30	7.41	91%	91.9°
2037-08-29 Sat	100	—	unknown	21:40–02:55 (good, 5.25 h)	87.1° 21:25	7.46	85%	97.7°
2037-08-30 Sun	100	—	unknown	21:40–03:00 (good, 5.33 h)	87.1° 21:20	7.52	78%	103.3°
2037-08-31 Mon	100	—	unknown	21:35–03:00 (good, 5.42 h)	87.1° 21:20	7.57	69%	108.5°
2037-09-01 Tue	100	—	unknown	21:35–03:05 (good, 5.5 h)	87.1° 21:15	7.63	60%	113.0°
2037-09-02 Wed	100	—	unknown	21:35–03:05 (good, 5.5 h)	87.1° 21:10	7.69	50%	116.6°
2037-09-03 Thu	100	—	unknown	21:30–03:00 (good, 5.5 h)	87.1° 21:05	7.74	40%	119.0°
2037-09-04 Fri	100	—	unknown	21:30–03:00 (good, 5.5 h)	87.1° 21:00	7.8	29%	119.8°
2037-09-05 Sat	100	—	unknown	21:25–02:55 (good, 5.5 h)	87.1° 21:00	7.85	20%	118.8°
2037-09-06 Sun	100	—	unknown	21:25–02:55 (good, 5.5 h)	87.1° 20:55	7.91	12%	115.9°
2037-09-07 Mon	100	—	unknown	21:25–02:50 (good, 5.42 h)	87.1° 20:50	7.96	5%	111.2°
2037-09-08 Tue	100	—	unknown	21:20–02:45 (good, 5.42 h)	87.1° 20:45	8.02	1%	105.1°
2037-09-09 Wed	100	—	unknown	21:20–02:40 (good, 5.33 h)	87.1° 20:45	8.07	0%	98.1°
2037-09-10 Thu	100	—	unknown	21:15–02:40 (good, 5.42 h)	87.1° 20:40	8.12	2%	90.6°
2037-09-11 Fri	100	—	unknown	21:15–02:35 (good, 5.33 h)	87.1° 20:35	8.18	7%	83.2°
2037-09-12 Sat	100	—	unknown	21:15–02:30 (good, 5.25 h)	87.1° 20:30	8.23	15%	76.2°
2037-09-13 Sun	100	—	unknown	21:10–02:25 (good, 5.25 h)	87.1° 20:25	8.28	24%	70.2°
2037-09-14 Mon	100	—	unknown	21:10–02:20 (good, 5.17 h)	87.1° 20:25	8.34	34%	65.4°
2037-09-15 Tue	97	—	unknown	21:05–02:20 (good, 5.25 h)	87.1° 20:20	8.39	45%	62.1°
2037-09-16 Wed	91	—	unknown	21:05–02:15 (good, 5.17 h)	87.1° 20:15	8.44	55%	60.5°
2037-09-17 Thu	84	—	unknown	21:05–02:10 (good, 5.08 h)	87.1° 20:10	8.49	65%	60.5°
2037-09-18 Fri	69	—	unknown	21:00–01:40 (good, 4.67 h)	87.1° 20:05	8.55	74%	62.0°
2037-09-19 Sat	61	—	unknown	21:00–00:45 (good, 3.75 h)	87.1° 20:05	8.6	82%	64.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-08-21&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.