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: 09-20 (100), 09-21 (100), 09-22 (100), 09-23 (100), 09-24 (100) — by astronomy; check the weather when the night is within four days.

2038-09-20astronomy score per night — click a bar for that night2038-10-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-09-20 Mon	100	—	unknown	21:00–01:50 (good, 4.83 h)	87.1° 20:00	8.64	57%	116.7°
2038-09-21 Tue	100	—	unknown	20:55–01:50 (good, 4.92 h)	87.1° 19:55	8.69	48%	117.8°
2038-09-22 Wed	100	—	unknown	20:55–01:50 (good, 4.92 h)	87.1° 19:55	8.74	38%	117.6°
2038-09-23 Thu	100	—	unknown	20:50–01:50 (good, 5.0 h)	87.1° 19:50	8.79	28%	115.9°
2038-09-24 Fri	100	—	unknown	20:50–01:45 (good, 4.92 h)	87.1° 19:45	8.84	19%	112.7°
2038-09-25 Sat	100	—	unknown	20:50–01:40 (good, 4.83 h)	87.1° 19:40	8.89	11%	108.2°
2038-09-26 Sun	100	—	unknown	20:45–01:35 (good, 4.83 h)	87.1° 19:35	8.94	5%	102.5°
2038-09-27 Mon	100	—	unknown	20:45–01:30 (good, 4.75 h)	87.1° 19:35	8.99	1%	96.1°
2038-09-28 Tue	100	—	unknown	20:45–01:30 (good, 4.75 h)	87.1° 19:30	9.04	0%	89.2°
2038-09-29 Wed	100	—	unknown	20:40–01:25 (good, 4.75 h)	87.1° 19:25	9.09	2%	82.2°
2038-09-30 Thu	100	—	unknown	20:40–01:20 (good, 4.67 h)	87.1° 19:20	9.14	7%	75.7°
2038-10-01 Fri	100	—	unknown	20:40–01:15 (good, 4.58 h)	87.1° 19:15	9.18	14%	70.1°
2038-10-02 Sat	100	—	unknown	20:35–01:15 (good, 4.67 h)	87.1° 19:15	9.23	23%	65.8°
2038-10-03 Sun	96	—	unknown	20:35–01:10 (good, 4.58 h)	87.1° 19:10	9.28	34%	63.1°
2038-10-04 Mon	89	—	unknown	20:35–01:05 (good, 4.5 h)	87.1° 19:05	9.33	45%	62.2°
2038-10-05 Tue	81	—	unknown	20:30–01:00 (good, 4.5 h)	87.1° 19:00	9.37	56%	63.0°
2038-10-06 Wed	67	—	unknown	20:30–00:35 (good, 4.08 h)	87.1° 19:00	9.42	66%	65.4°
2038-10-07 Thu	60	—	unknown	20:25–00:20 (good, 3.92 h)	87.1° 18:55	9.47	75%	68.9°
2038-10-08 Fri	56	—	unknown	20:25–23:25 (good, 3.0 h)	87.1° 18:50	9.51	83%	73.3°
2038-10-09 Sat	55	—	unknown	20:25–23:00 (good, 2.58 h)	87.1° 18:45	9.56	90%	78.4°
2038-10-10 Sun	56	—	unknown	20:25–22:55 (good, 2.5 h)	87.1° 18:40	9.6	95%	83.9°
2038-10-11 Mon	60	—	unknown	20:20–23:10 (good, 2.83 h)	87.1° 18:40	9.65	98%	89.5°
2038-10-12 Tue	64	—	unknown	20:20–23:30 (good, 3.17 h)	87.1° 18:35	9.69	100%	95.0°
2038-10-13 Wed	70	—	unknown	20:20–23:55 (good, 3.58 h)	87.1° 18:30	9.74	99%	100.4°
2038-10-14 Thu	76	—	unknown	20:15–00:00 (good, 3.75 h)	87.1° 18:25	9.78	97%	105.3°
2038-10-15 Fri	82	—	unknown	20:15–00:00 (good, 3.75 h)	87.1° 18:20	9.82	93%	109.7°
2038-10-16 Sat	96	—	unknown	20:15–00:00 (good, 3.75 h)	87.1° 18:20	9.87	88%	113.3°
2038-10-17 Sun	99	—	unknown	20:10–00:00 (good, 3.83 h)	87.1° 18:15	9.91	81%	115.9°
2038-10-18 Mon	100	—	unknown	20:10–00:00 (good, 3.83 h)	87.1° 18:10	9.95	73%	117.4°
2038-10-19 Tue	100	—	unknown	20:10–00:00 (good, 3.83 h)	87.1° 18:05	10.0	64%	117.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-09-20&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.