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 Triangulum Pinwheel: 08-17 (100), 08-18 (100), 08-30 (100), 08-31 (100), 09-01 (100) — by astronomy; check the weather when the night is within four days.

2043-08-17astronomy score per night — click a bar for that night2043-09-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-08-17 Mon	100	—	unknown	00:05–04:50 (good, 4.75 h)	79.2° 05:10	6.75	92%	101.8°
2043-08-18 Tue	100	—	unknown	00:15–04:50 (good, 4.58 h)	79.2° 05:10	6.81	97%	89.6°
2043-08-19 Wed	69	—	unknown	01:35–04:55 (good, 3.33 h)	79.2° 05:05	6.87	99%	77.1°
2043-08-20 Thu	51	—	unknown	04:10–04:55 (good, 0.75 h)	79.2° 05:00	6.92	100%	64.3°
2043-08-21 Fri	37	—	unknown	23:20–04:55 (marginal, 5.58 h)	79.2° 04:55	6.98	98%	51.5°
2043-08-22 Sat	26	—	unknown	23:20–05:00 (marginal, 5.67 h)	79.2° 04:50	7.04	94%	38.8°
2043-08-23 Sun	25	—	unknown	23:15–05:00 (marginal, 5.75 h)	79.2° 04:50	7.1	87%	26.9°
2043-08-24 Mon	33	—	unknown	23:00–05:00 (marginal, 6.0 h)	79.2° 04:45	7.15	78%	18.0°
2043-08-25 Tue	46	—	unknown	22:45–05:00 (marginal, 6.25 h)	79.2° 04:40	7.21	68%	17.7°
2043-08-26 Wed	64	—	unknown	23:40–03:40 (good, 4.0 h)	79.2° 04:35	7.27	57%	26.3°
2043-08-27 Thu	81	—	unknown	23:05–05:05 (good, 6.0 h)	79.2° 04:35	7.32	46%	38.3°
2043-08-28 Fri	88	—	unknown	23:00–05:05 (good, 6.08 h)	79.2° 04:30	7.38	34%	51.2°
2043-08-29 Sat	96	—	unknown	22:55–05:10 (good, 6.25 h)	79.2° 04:25	7.44	24%	64.4°
2043-08-30 Sun	100	—	unknown	22:55–05:10 (good, 6.25 h)	79.2° 04:20	7.49	15%	77.7°
2043-08-31 Mon	100	—	unknown	22:50–05:10 (good, 6.33 h)	79.2° 04:15	7.55	8%	90.9°
2043-09-01 Tue	100	—	unknown	22:45–05:10 (good, 6.42 h)	79.2° 04:15	7.6	3%	104.0°
2043-09-02 Wed	100	—	unknown	22:40–05:15 (good, 6.58 h)	79.2° 04:10	7.66	0%	116.8°
2043-09-03 Thu	100	—	unknown	22:40–05:15 (good, 6.58 h)	79.2° 04:05	7.72	0%	129.2°
2043-09-04 Fri	100	—	unknown	22:35–05:15 (good, 6.67 h)	79.2° 04:00	7.77	2%	141.0°
2043-09-05 Sat	100	—	unknown	22:30–05:15 (good, 6.75 h)	79.2° 03:55	7.83	6%	151.7°
2043-09-06 Sun	100	—	unknown	22:25–05:20 (good, 6.92 h)	79.2° 03:55	7.88	11%	160.4°
2043-09-07 Mon	100	—	unknown	22:20–05:20 (good, 7.0 h)	79.2° 03:50	7.94	18%	163.6°
2043-09-08 Tue	100	—	unknown	22:20–05:20 (good, 7.0 h)	79.2° 03:45	7.99	26%	159.1°
2043-09-09 Wed	100	—	unknown	22:15–05:20 (good, 7.08 h)	79.2° 03:40	8.05	35%	150.4°
2043-09-10 Thu	100	—	unknown	22:15–05:25 (good, 7.17 h)	79.2° 03:40	8.1	44%	140.2°
2043-09-11 Fri	100	—	unknown	22:10–05:25 (good, 7.25 h)	79.2° 03:35	8.15	54%	129.3°
2043-09-12 Sat	100	—	unknown	22:10–05:25 (good, 7.25 h)	79.2° 03:30	8.21	63%	118.0°
2043-09-13 Sun	100	—	unknown	22:10–05:25 (good, 7.25 h)	79.2° 03:25	8.26	72%	106.3°
2043-09-14 Mon	100	—	unknown	22:15–05:30 (good, 7.25 h)	79.2° 03:20	8.31	81%	94.3°
2043-09-15 Tue	100	—	unknown	22:40–05:30 (good, 6.83 h)	79.2° 03:20	8.37	88%	82.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-08-17&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.