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: 09-12 (100), 09-13 (100), 09-14 (100), 09-15 (100), 09-16 (100) — by astronomy; check the weather when the night is within four days.

2039-09-01astronomy score per night — click a bar for that night2039-09-30

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2039-09-20 Tue	100	—	unknown	21:30–05:35 (good, 8.08 h)	79.2° 03:00	8.62	8%	157.0°
2039-09-21 Wed	100	—	unknown	21:25–05:35 (good, 8.17 h)	79.2° 02:55	8.68	16%	155.0°
2039-09-22 Thu	100	—	unknown	21:25–05:40 (good, 8.25 h)	79.2° 02:50	8.73	25%	146.7°
2039-09-23 Fri	100	—	unknown	21:20–05:40 (good, 8.33 h)	79.2° 02:45	8.78	36%	135.5°
2039-09-24 Sat	100	—	unknown	21:20–05:40 (good, 8.33 h)	79.2° 02:40	8.83	47%	123.3°
2039-09-25 Sun	100	—	unknown	21:20–05:40 (good, 8.33 h)	79.2° 02:40	8.88	58%	110.6°
2039-09-26 Mon	100	—	unknown	21:20–05:45 (good, 8.42 h)	79.2° 02:35	8.93	69%	97.8°
2039-09-27 Tue	100	—	unknown	21:30–05:45 (good, 8.25 h)	79.2° 02:30	8.98	79%	85.0°
2039-09-28 Wed	100	—	unknown	22:35–05:45 (good, 7.17 h)	79.2° 02:25	9.03	87%	72.4°
2039-09-29 Thu	99	—	unknown	01:35–05:45 (good, 4.17 h)	79.2° 02:25	9.08	94%	60.1°
2039-09-30 Fri	61	—	unknown	04:45–05:45 (good, 1.0 h)	79.2° 02:20	9.12	98%	48.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-09-01&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.