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), 08-19 (100), 08-20 (100), 08-21 (100) — by astronomy; check the weather when the night is within four days.

2028-08-14astronomy score per night — click a bar for that night2028-09-12

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-08-14 Mon	82	—	unknown	23:55–04:45 (good, 4.83 h)	79.1° 05:20	6.61	35%	38.9°
2028-08-15 Tue	90	—	unknown	23:50–04:50 (good, 5.0 h)	79.1° 05:15	6.67	26%	51.3°
2028-08-16 Wed	98	—	unknown	23:45–04:50 (good, 5.08 h)	79.1° 05:15	6.73	16%	64.4°
2028-08-17 Thu	100	—	unknown	23:40–04:50 (good, 5.17 h)	79.1° 05:10	6.79	9%	78.1°
2028-08-18 Fri	100	—	unknown	23:35–04:55 (good, 5.33 h)	79.1° 05:05	6.84	3%	92.3°
2028-08-19 Sat	100	—	unknown	23:35–04:55 (good, 5.33 h)	79.1° 05:00	6.9	0%	106.8°
2028-08-20 Sun	100	—	unknown	23:30–04:55 (good, 5.42 h)	79.1° 04:55	6.96	0%	121.3°
2028-08-21 Mon	100	—	unknown	23:25–04:55 (good, 5.5 h)	79.1° 04:55	7.02	4%	135.7°
2028-08-22 Tue	100	—	unknown	23:20–05:00 (good, 5.67 h)	79.1° 04:50	7.07	9%	149.4°
2028-08-23 Wed	100	—	unknown	23:20–05:00 (good, 5.67 h)	79.1° 04:45	7.13	17%	161.1°
2028-08-24 Thu	100	—	unknown	23:15–05:00 (good, 5.75 h)	79.1° 04:40	7.19	27%	165.6°
2028-08-25 Fri	100	—	unknown	23:10–05:05 (good, 5.92 h)	79.1° 04:35	7.25	38%	158.8°
2028-08-26 Sat	100	—	unknown	23:10–05:05 (good, 5.92 h)	79.1° 04:35	7.3	49%	147.5°
2028-08-27 Sun	100	—	unknown	23:05–05:05 (good, 6.0 h)	79.1° 04:30	7.36	59%	135.4°
2028-08-28 Mon	100	—	unknown	23:05–05:05 (good, 6.0 h)	79.1° 04:25	7.42	69%	123.3°
2028-08-29 Tue	100	—	unknown	23:05–05:10 (good, 6.08 h)	79.1° 04:20	7.47	78%	111.2°
2028-08-30 Wed	100	—	unknown	23:10–05:10 (good, 6.0 h)	79.1° 04:20	7.53	86%	99.3°
2028-08-31 Thu	100	—	unknown	23:30–05:10 (good, 5.67 h)	79.1° 04:15	7.58	92%	87.5°
2028-09-01 Fri	100	—	unknown	00:50–05:15 (good, 4.42 h)	79.1° 04:10	7.64	96%	75.8°
2028-09-02 Sat	68	—	unknown	03:20–05:15 (good, 1.92 h)	79.1° 04:05	7.7	99%	64.3°
2028-09-03 Sun	49	—	unknown	22:30–05:15 (marginal, 6.75 h)	79.1° 04:00	7.75	100%	53.0°
2028-09-04 Mon	34	—	unknown	22:35–05:15 (marginal, 6.67 h)	79.1° 04:00	7.81	99%	41.8°
2028-09-05 Tue	23	—	unknown	22:35–05:20 (marginal, 6.75 h)	79.1° 03:55	7.86	96%	31.1°
2028-09-06 Wed	25	—	unknown	22:20–05:20 (marginal, 7.0 h)	79.1° 03:50	7.92	92%	21.4°
2028-09-07 Thu	32	—	unknown	22:05–05:20 (marginal, 7.25 h)	79.1° 03:45	7.97	86%	15.0°
2028-09-08 Fri	42	—	unknown	21:55–05:20 (marginal, 7.42 h)	79.1° 03:40	8.03	79%	16.4°
2028-09-09 Sat	55	—	unknown	21:40–05:25 (marginal, 7.75 h)	79.1° 03:40	8.08	71%	24.6°
2028-09-10 Sun	80	—	unknown	22:05–03:00 (good, 4.92 h)	79.1° 03:35	8.13	61%	35.4°
2028-09-11 Mon	86	—	unknown	22:05–05:25 (good, 7.33 h)	79.1° 03:30	8.19	51%	47.2°
2028-09-12 Tue	94	—	unknown	22:00–05:25 (good, 7.42 h)	79.1° 03:25	8.24	41%	59.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-08-14&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.