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: 09-21 (100), 09-22 (100), 09-23 (100), 09-24 (100), 09-25 (100) — by astronomy; check the weather when the night is within four days.

2041-09-21astronomy score per night — click a bar for that night2041-10-20

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-09-21 Sat	100	—	unknown	20:55–01:55 (good, 5.0 h)	87.1° 19:55	8.7	10%	107.6°
2041-09-22 Sun	100	—	unknown	20:55–01:50 (good, 4.92 h)	87.1° 19:50	8.75	5%	104.0°
2041-09-23 Mon	100	—	unknown	20:50–01:45 (good, 4.92 h)	87.1° 19:50	8.8	2%	99.9°
2041-09-24 Tue	100	—	unknown	20:50–01:45 (good, 4.92 h)	87.1° 19:45	8.85	0%	95.4°
2041-09-25 Wed	100	—	unknown	20:50–01:40 (good, 4.83 h)	87.1° 19:40	8.9	0%	90.7°
2041-09-26 Thu	100	—	unknown	20:45–01:35 (good, 4.83 h)	87.1° 19:35	8.95	2%	85.9°
2041-09-27 Fri	100	—	unknown	20:45–01:30 (good, 4.75 h)	87.1° 19:30	9.0	6%	81.3°
2041-09-28 Sat	100	—	unknown	20:45–01:25 (good, 4.67 h)	87.1° 19:30	9.05	12%	76.9°
2041-09-29 Sun	100	—	unknown	20:40–01:25 (good, 4.75 h)	87.1° 19:25	9.1	19%	73.0°
2041-09-30 Mon	100	—	unknown	20:40–01:20 (good, 4.67 h)	87.1° 19:20	9.15	27%	69.8°
2041-10-01 Tue	98	—	unknown	20:35–01:15 (good, 4.67 h)	87.1° 19:15	9.2	37%	67.6°
2041-10-02 Wed	91	—	unknown	20:35–01:10 (good, 4.58 h)	87.1° 19:10	9.24	48%	66.6°
2041-10-03 Thu	83	—	unknown	20:35–01:10 (good, 4.58 h)	87.1° 19:10	9.29	59%	66.9°
2041-10-04 Fri	68	—	unknown	20:30–00:40 (good, 4.17 h)	87.1° 19:05	9.34	70%	68.7°
2041-10-05 Sat	60	—	unknown	20:30–00:10 (good, 3.67 h)	87.1° 19:00	9.39	80%	71.8°
2041-10-06 Sun	56	—	unknown	20:30–23:15 (good, 2.75 h)	87.1° 18:55	9.43	88%	76.2°
2041-10-07 Mon	56	—	unknown	20:25–22:55 (good, 2.5 h)	87.1° 18:55	9.48	95%	81.5°
2041-10-08 Tue	58	—	unknown	20:25–23:00 (good, 2.58 h)	87.1° 18:50	9.53	99%	87.3°
2041-10-09 Wed	64	—	unknown	20:25–23:25 (good, 3.0 h)	87.1° 18:45	9.57	100%	93.3°
2041-10-10 Thu	71	—	unknown	20:20–23:55 (good, 3.58 h)	87.1° 18:40	9.62	98%	99.0°
2041-10-11 Fri	79	—	unknown	20:20–00:10 (good, 3.83 h)	87.1° 18:35	9.66	94%	104.0°
2041-10-12 Sat	96	—	unknown	20:20–00:15 (good, 3.92 h)	87.1° 18:35	9.71	87%	108.1°
2041-10-13 Sun	100	—	unknown	20:15–00:15 (good, 4.0 h)	87.1° 18:30	9.75	78%	111.1°
2041-10-14 Mon	100	—	unknown	20:15–00:15 (good, 4.0 h)	87.1° 18:25	9.79	69%	112.9°
2041-10-15 Tue	100	—	unknown	20:15–00:15 (good, 4.0 h)	87.1° 18:20	9.84	60%	113.4°
2041-10-16 Wed	100	—	unknown	20:15–00:10 (good, 3.92 h)	87.1° 18:15	9.88	50%	112.7°
2041-10-17 Thu	100	—	unknown	20:10–00:15 (good, 4.08 h)	87.1° 18:15	9.92	40%	111.0°
2041-10-18 Fri	100	—	unknown	20:10–00:10 (good, 4.0 h)	87.1° 18:10	9.97	31%	108.4°
2041-10-19 Sat	100	—	unknown	20:10–00:05 (good, 3.92 h)	87.1° 18:05	10.01	22%	105.0°
2041-10-20 Sun	100	—	unknown	20:05–00:00 (good, 3.92 h)	87.1° 18:00	10.05	15%	101.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-09-21&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.