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: 09-23 (100), 09-24 (100), 09-25 (100), 09-26 (100), 09-27 (100) — by astronomy; check the weather when the night is within four days.

2028-09-23astronomy score per night — click a bar for that night2028-10-22

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-09-23 Sat	100	—	unknown	21:20–05:40 (good, 8.33 h)	79.1° 02:45	8.81	33%	139.1°
2028-09-24 Sun	100	—	unknown	21:15–05:40 (good, 8.42 h)	79.1° 02:40	8.86	44%	126.6°
2028-09-25 Mon	100	—	unknown	21:15–05:45 (good, 8.5 h)	79.1° 02:35	8.91	54%	114.3°
2028-09-26 Tue	100	—	unknown	21:15–05:45 (good, 8.5 h)	79.1° 02:30	8.96	64%	102.3°
2028-09-27 Wed	100	—	unknown	21:20–05:45 (good, 8.42 h)	79.1° 02:25	9.01	73%	90.4°
2028-09-28 Thu	100	—	unknown	21:55–05:45 (good, 7.83 h)	79.1° 02:25	9.06	81%	78.7°
2028-09-29 Fri	100	—	unknown	23:25–05:45 (good, 6.33 h)	79.1° 02:20	9.11	88%	67.2°
2028-09-30 Sat	96	—	unknown	02:45–05:50 (good, 3.08 h)	79.1° 02:15	9.16	93%	55.9°
2028-10-01 Sun	59	—	unknown	20:45–05:50 (marginal, 9.08 h)	79.1° 02:10	9.2	97%	44.7°
2028-10-02 Mon	42	—	unknown	20:55–05:50 (marginal, 8.92 h)	79.1° 02:10	9.25	99%	33.8°
2028-10-03 Tue	30	—	unknown	03:15–05:50 (marginal, 2.58 h)	79.1° 02:05	9.3	100%	23.8°
2028-10-04 Wed	28	—	unknown	20:35–23:50 (marginal, 3.25 h)	79.1° 02:00	9.35	98%	16.1°
2028-10-05 Thu	33	—	unknown	20:30–00:50 (marginal, 4.33 h)	79.1° 01:55	9.39	95%	15.4°
2028-10-06 Fri	42	—	unknown	20:30–03:10 (marginal, 6.67 h)	79.1° 01:50	9.44	90%	22.4°
2028-10-07 Sat	72	—	unknown	20:25–20:40 (good, 0.25 h)	79.1° 01:50	9.49	84%	32.7°
2028-10-08 Sun	85	—	unknown	20:25–00:25 (good, 4.0 h)	79.1° 01:45	9.53	76%	44.2°
2028-10-09 Mon	92	—	unknown	20:25–04:25 (good, 8.0 h)	79.1° 01:40	9.58	66%	56.3°
2028-10-10 Tue	100	—	unknown	20:20–06:00 (good, 9.67 h)	79.1° 01:35	9.62	56%	68.9°
2028-10-11 Wed	100	—	unknown	20:20–06:00 (good, 9.67 h)	79.1° 01:30	9.67	45%	81.9°
2028-10-12 Thu	100	—	unknown	20:20–06:00 (good, 9.67 h)	79.1° 01:30	9.71	34%	95.3°
2028-10-13 Fri	100	—	unknown	20:15–06:05 (good, 9.83 h)	79.1° 01:25	9.76	24%	109.0°
2028-10-14 Sat	100	—	unknown	20:15–06:05 (good, 9.83 h)	79.1° 01:20	9.8	15%	123.0°
2028-10-15 Sun	100	—	unknown	20:15–06:05 (good, 9.83 h)	79.1° 01:15	9.84	7%	137.1°
2028-10-16 Mon	100	—	unknown	20:15–06:05 (good, 9.83 h)	79.1° 01:15	9.89	2%	150.7°
2028-10-17 Tue	100	—	unknown	20:10–06:05 (good, 9.92 h)	79.1° 01:10	9.93	0%	162.0°
2028-10-18 Wed	100	—	unknown	20:10–06:10 (good, 10.0 h)	79.1° 01:05	9.97	1%	164.9°
2028-10-19 Thu	100	—	unknown	20:10–06:10 (good, 10.0 h)	79.1° 01:00	10.01	5%	156.3°
2028-10-20 Fri	100	—	unknown	20:05–06:10 (good, 10.08 h)	79.1° 00:55	10.06	11%	144.0°
2028-10-21 Sat	100	—	unknown	20:05–06:10 (good, 10.08 h)	79.1° 00:55	10.1	19%	131.2°
2028-10-22 Sun	100	—	unknown	20:05–06:10 (good, 10.08 h)	79.1° 00:50	10.14	28%	118.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-09-23&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.