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 Andromeda Galaxy: 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.

2043-08-20astronomy score per night — click a bar for that night2043-09-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-08-20 Thu	62	—	unknown	04:15–04:55 (good, 0.67 h)	89.8° 04:10	6.92	100%	63.9°
2043-08-21 Fri	48	—	unknown	21:55–04:55 (marginal, 7.0 h)	89.8° 04:05	6.98	98%	53.0°
2043-08-22 Sat	40	—	unknown	21:55–05:00 (marginal, 7.08 h)	89.7° 04:00	7.04	94%	43.0°
2043-08-23 Sun	42	—	unknown	21:55–05:00 (marginal, 7.08 h)	89.5° 03:55	7.1	87%	35.1°
2043-08-24 Mon	65	—	unknown	21:50–22:05 (good, 0.25 h)	89.6° 03:55	7.15	78%	31.0°
2043-08-25 Tue	81	—	unknown	22:50–01:20 (good, 2.5 h)	89.8° 03:50	7.21	68%	32.4°
2043-08-26 Wed	85	—	unknown	21:50–05:05 (good, 7.25 h)	89.8° 03:45	7.27	57%	38.8°
2043-08-27 Thu	90	—	unknown	21:45–05:05 (good, 7.33 h)	89.6° 03:40	7.32	46%	48.1°
2043-08-28 Fri	97	—	unknown	21:45–05:05 (good, 7.33 h)	89.5° 03:40	7.38	34%	59.0°
2043-08-29 Sat	100	—	unknown	21:40–05:10 (good, 7.5 h)	89.7° 03:35	7.44	24%	70.5°
2043-08-30 Sun	100	—	unknown	21:40–05:10 (good, 7.5 h)	89.8° 03:30	7.49	15%	82.4°
2043-08-31 Mon	100	—	unknown	21:40–05:10 (good, 7.5 h)	89.8° 03:25	7.55	8%	94.2°
2043-09-01 Tue	100	—	unknown	21:35–05:10 (good, 7.58 h)	89.6° 03:20	7.6	3%	105.9°
2043-09-02 Wed	100	—	unknown	21:35–05:15 (good, 7.67 h)	89.6° 03:20	7.66	0%	117.0°
2043-09-03 Thu	100	—	unknown	21:30–05:15 (good, 7.75 h)	89.7° 03:15	7.72	0%	127.5°
2043-09-04 Fri	100	—	unknown	21:30–05:15 (good, 7.75 h)	89.8° 03:10	7.77	2%	136.8°
2043-09-05 Sat	100	—	unknown	21:30–05:15 (good, 7.75 h)	89.7° 03:05	7.83	6%	144.2°
2043-09-06 Sun	100	—	unknown	21:25–05:20 (good, 7.92 h)	89.5° 03:00	7.88	11%	148.5°
2043-09-07 Mon	100	—	unknown	21:25–05:20 (good, 7.92 h)	89.6° 03:00	7.94	18%	148.9°
2043-09-08 Tue	100	—	unknown	21:20–05:20 (good, 8.0 h)	89.8° 02:55	7.99	26%	145.3°
2043-09-09 Wed	100	—	unknown	21:20–05:20 (good, 8.0 h)	89.8° 02:50	8.05	35%	138.8°
2043-09-10 Thu	100	—	unknown	21:20–05:25 (good, 8.08 h)	89.7° 02:45	8.1	44%	130.6°
2043-09-11 Fri	100	—	unknown	21:15–05:25 (good, 8.17 h)	89.5° 02:45	8.15	54%	121.4°
2043-09-12 Sat	100	—	unknown	21:15–05:25 (good, 8.17 h)	89.7° 02:40	8.21	63%	111.6°
2043-09-13 Sun	100	—	unknown	21:10–05:25 (good, 8.25 h)	89.8° 02:35	8.26	72%	101.3°
2043-09-14 Mon	100	—	unknown	21:10–05:30 (good, 8.33 h)	89.8° 02:30	8.31	81%	90.5°
2043-09-15 Tue	100	—	unknown	21:20–05:30 (good, 8.17 h)	89.6° 02:25	8.37	88%	79.5°
2043-09-16 Wed	100	—	unknown	23:15–05:30 (good, 6.25 h)	89.6° 02:25	8.42	94%	68.2°
2043-09-17 Thu	65	—	unknown	04:00–05:30 (good, 1.5 h)	89.7° 02:20	8.47	98%	57.1°
2043-09-18 Fri	53	—	unknown	21:00–05:35 (marginal, 8.58 h)	89.8° 02:15	8.52	100%	46.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-08-20&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.