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: 08-21 (100), 08-22 (100), 08-23 (100), 08-24 (100), 08-25 (100) — by astronomy; check the weather when the night is within four days.

2039-08-21astronomy score per night — click a bar for that night2039-09-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-08-21 Sun	100	—	unknown	23:30–04:55 (good, 5.42 h)	79.2° 04:55	6.98	5%	134.3°
2039-08-22 Mon	100	—	unknown	23:25–05:00 (good, 5.58 h)	79.2° 04:50	7.04	11%	145.0°
2039-08-23 Tue	100	—	unknown	23:20–05:00 (good, 5.67 h)	79.2° 04:50	7.09	18%	153.6°
2039-08-24 Wed	100	—	unknown	23:15–05:00 (good, 5.75 h)	79.2° 04:45	7.15	28%	157.1°
2039-08-25 Thu	100	—	unknown	23:15–05:00 (good, 5.75 h)	79.2° 04:40	7.21	38%	153.2°
2039-08-26 Fri	100	—	unknown	23:15–05:05 (good, 5.83 h)	79.2° 04:35	7.26	50%	144.1°
2039-08-27 Sat	100	—	unknown	23:10–05:05 (good, 5.92 h)	79.2° 04:35	7.32	61%	132.7°
2039-08-28 Sun	100	—	unknown	23:10–05:05 (good, 5.92 h)	79.2° 04:30	7.38	72%	120.3°
2039-08-29 Mon	100	—	unknown	23:10–05:10 (good, 6.0 h)	79.2° 04:25	7.43	82%	107.4°
2039-08-30 Tue	100	—	unknown	23:15–05:10 (good, 5.92 h)	79.2° 04:20	7.49	90%	94.3°
2039-08-31 Wed	100	—	unknown	00:05–05:10 (good, 5.08 h)	79.2° 04:15	7.55	95%	81.2°
2039-09-01 Thu	71	—	unknown	01:40–05:10 (good, 3.5 h)	79.2° 04:15	7.6	99%	68.4°
2039-09-02 Fri	55	—	unknown	22:30–05:50 (marginal, 7.33 h)	79.2° 04:10	7.66	100%	56.1°
2039-09-03 Sat	39	—	unknown	22:30–05:15 (marginal, 6.75 h)	79.2° 04:05	7.71	98%	44.5°
2039-09-04 Sun	29	—	unknown	22:25–05:15 (marginal, 6.83 h)	79.2° 04:00	7.77	95%	34.1°
2039-09-05 Mon	32	—	unknown	22:15–05:15 (marginal, 7.0 h)	79.2° 03:55	7.82	89%	26.2°
2039-09-06 Tue	41	—	unknown	22:05–05:20 (marginal, 7.25 h)	79.2° 03:55	7.88	82%	22.9°
2039-09-07 Wed	59	—	unknown	22:20–22:25 (good, 0.08 h)	79.2° 03:50	7.93	74%	25.4°
2039-09-08 Thu	80	—	unknown	22:20–02:05 (good, 3.75 h)	79.2° 03:45	7.99	65%	32.3°
2039-09-09 Fri	85	—	unknown	22:15–05:20 (good, 7.08 h)	79.2° 03:40	8.04	56%	41.3°
2039-09-10 Sat	90	—	unknown	22:10–05:25 (good, 7.25 h)	79.2° 03:40	8.1	47%	51.3°
2039-09-11 Sun	96	—	unknown	22:05–05:25 (good, 7.33 h)	79.2° 03:35	8.15	37%	61.8°
2039-09-12 Mon	100	—	unknown	22:00–05:25 (good, 7.42 h)	79.2° 03:30	8.2	28%	72.7°
2039-09-13 Tue	100	—	unknown	22:00–05:25 (good, 7.42 h)	79.2° 03:25	8.26	20%	83.9°
2039-09-14 Wed	100	—	unknown	21:55–05:30 (good, 7.58 h)	79.2° 03:20	8.31	13%	95.3°
2039-09-15 Thu	100	—	unknown	21:50–05:30 (good, 7.67 h)	79.2° 03:20	8.36	7%	107.0°
2039-09-16 Fri	100	—	unknown	21:45–05:30 (good, 7.75 h)	79.2° 03:15	8.42	3%	118.8°
2039-09-17 Sat	100	—	unknown	21:45–05:30 (good, 7.75 h)	79.2° 03:10	8.47	0%	130.6°
2039-09-18 Sun	100	—	unknown	21:40–05:35 (good, 7.92 h)	79.2° 03:05	8.52	1%	141.9°
2039-09-19 Mon	100	—	unknown	21:35–05:35 (good, 8.0 h)	79.2° 03:00	8.57	3%	151.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-08-21&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.