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), 09-24 (100), 09-25 (100), 09-26 (100) — by astronomy; check the weather when the night is within four days.

2027-09-12astronomy score per night — click a bar for that night2027-10-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-09-12 Sun	100	—	unknown	23:40–05:25 (good, 5.75 h)	79.1° 03:30	8.2	92%	77.4°
2027-09-13 Mon	100	—	unknown	01:35–05:25 (good, 3.83 h)	79.1° 03:25	8.25	96%	65.9°
2027-09-14 Tue	64	—	unknown	04:40–05:30 (good, 0.83 h)	79.1° 03:20	8.31	99%	54.4°
2027-09-15 Wed	45	—	unknown	21:55–05:30 (marginal, 7.58 h)	79.1° 03:20	8.36	100%	42.9°
2027-09-16 Thu	28	—	unknown	22:00–01:15 (marginal, 3.25 h)	79.1° 03:15	8.41	99%	31.6°
2027-09-17 Fri	25	—	unknown	21:45–01:25 (marginal, 3.67 h)	79.1° 03:10	8.46	96%	21.3°
2027-09-18 Sat	31	—	unknown	21:30–05:35 (marginal, 8.08 h)	79.1° 03:05	8.52	91%	14.7°
2027-09-19 Sun	41	—	unknown	21:15–05:35 (marginal, 8.33 h)	79.1° 03:00	8.57	84%	17.2°
2027-09-20 Mon	53	—	unknown	21:00–05:35 (marginal, 8.58 h)	79.1° 03:00	8.62	76%	26.6°
2027-09-21 Tue	81	—	unknown	21:25–01:55 (good, 4.5 h)	79.1° 02:55	8.67	66%	38.4°
2027-09-22 Wed	88	—	unknown	21:25–05:40 (good, 8.25 h)	79.1° 02:50	8.72	56%	51.2°
2027-09-23 Thu	97	—	unknown	21:20–05:40 (good, 8.33 h)	79.1° 02:45	8.77	44%	64.4°
2027-09-24 Fri	100	—	unknown	21:15–05:40 (good, 8.42 h)	79.1° 02:40	8.82	33%	78.1°
2027-09-25 Sat	100	—	unknown	21:10–05:40 (good, 8.5 h)	79.1° 02:40	8.87	23%	92.0°
2027-09-26 Sun	100	—	unknown	21:05–05:45 (good, 8.67 h)	79.1° 02:35	8.92	14%	106.1°
2027-09-27 Mon	100	—	unknown	21:05–05:45 (good, 8.67 h)	79.1° 02:30	8.97	7%	120.3°
2027-09-28 Tue	100	—	unknown	21:00–05:45 (good, 8.75 h)	79.1° 02:25	9.02	2%	134.3°
2027-09-29 Wed	100	—	unknown	20:55–05:45 (good, 8.83 h)	79.1° 02:20	9.07	0%	147.7°
2027-09-30 Thu	100	—	unknown	20:50–05:45 (good, 8.92 h)	79.1° 02:20	9.12	1%	159.4°
2027-10-01 Fri	100	—	unknown	20:45–05:50 (good, 9.08 h)	79.1° 02:15	9.17	4%	165.6°
2027-10-02 Sat	100	—	unknown	20:45–05:50 (good, 9.08 h)	79.1° 02:10	9.22	10%	160.8°
2027-10-03 Sun	100	—	unknown	20:40–05:50 (good, 9.17 h)	79.1° 02:05	9.26	17%	150.5°
2027-10-04 Mon	100	—	unknown	20:40–05:50 (good, 9.17 h)	79.1° 02:05	9.31	26%	138.9°
2027-10-05 Tue	100	—	unknown	20:35–05:55 (good, 9.33 h)	79.1° 02:00	9.36	35%	127.1°
2027-10-06 Wed	100	—	unknown	20:35–05:55 (good, 9.33 h)	79.1° 01:55	9.4	44%	115.5°
2027-10-07 Thu	100	—	unknown	20:35–05:55 (good, 9.33 h)	79.1° 01:50	9.45	54%	103.9°
2027-10-08 Fri	100	—	unknown	20:35–05:55 (good, 9.33 h)	79.1° 01:45	9.5	63%	92.4°
2027-10-09 Sat	100	—	unknown	20:40–05:55 (good, 9.25 h)	79.1° 01:45	9.54	72%	80.9°
2027-10-10 Sun	100	—	unknown	21:55–06:00 (good, 8.08 h)	79.1° 01:40	9.59	80%	69.5°
2027-10-11 Mon	98	—	unknown	00:45–06:00 (good, 5.25 h)	79.1° 01:35	9.63	87%	57.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-09-12&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.