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: 09-18 (100), 09-19 (100), 09-20 (100), 09-21 (100), 10-02 (100) — by astronomy; check the weather when the night is within four days.

2037-09-18astronomy score per night — click a bar for that night2037-10-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-09-18 Fri	100	—	unknown	21:55–05:35 (good, 7.67 h)	79.2° 03:05	8.55	74%	97.4°
2037-09-19 Sat	100	—	unknown	22:00–05:35 (good, 7.58 h)	79.2° 03:00	8.6	82%	86.3°
2037-09-20 Sun	100	—	unknown	23:05–05:35 (good, 6.5 h)	79.2° 02:55	8.65	89%	75.3°
2037-09-21 Mon	100	—	unknown	00:35–05:40 (good, 5.08 h)	79.2° 02:50	8.7	94%	64.6°
2037-09-22 Tue	66	—	unknown	04:00–05:40 (good, 1.67 h)	79.2° 02:50	8.75	98%	54.2°
2037-09-23 Wed	56	—	unknown	21:10–05:40 (marginal, 8.5 h)	79.2° 02:45	8.8	100%	44.3°
2037-09-24 Thu	39	—	unknown	21:10–05:40 (marginal, 8.5 h)	79.2° 02:40	8.85	100%	35.3°
2037-09-25 Fri	32	—	unknown	21:00–05:40 (marginal, 8.67 h)	79.2° 02:35	8.9	98%	28.1°
2037-09-26 Sat	37	—	unknown	20:50–05:45 (marginal, 8.92 h)	79.1° 02:35	8.95	94%	24.5°
2037-09-27 Sun	58	—	unknown	21:00–21:05 (good, 0.08 h)	79.2° 02:30	9.0	89%	26.0°
2037-09-28 Mon	81	—	unknown	20:55–21:35 (good, 0.67 h)	79.2° 02:25	9.05	83%	32.1°
2037-09-29 Tue	85	—	unknown	20:55–00:50 (good, 3.92 h)	79.2° 02:20	9.1	75%	40.9°
2037-09-30 Wed	90	—	unknown	20:50–04:40 (good, 7.83 h)	79.2° 02:15	9.15	66%	51.1°
2037-10-01 Thu	97	—	unknown	20:45–05:50 (good, 9.08 h)	79.2° 02:15	9.2	55%	62.3°
2037-10-02 Fri	100	—	unknown	20:40–05:50 (good, 9.17 h)	79.2° 02:10	9.24	45%	74.1°
2037-10-03 Sat	100	—	unknown	20:40–05:50 (good, 9.17 h)	79.2° 02:05	9.29	34%	86.4°
2037-10-04 Sun	100	—	unknown	20:35–05:50 (good, 9.25 h)	79.2° 02:00	9.34	24%	99.2°
2037-10-05 Mon	100	—	unknown	20:30–05:55 (good, 9.42 h)	79.2° 01:55	9.38	15%	112.3°
2037-10-06 Tue	100	—	unknown	20:30–05:55 (good, 9.42 h)	79.2° 01:55	9.43	7%	125.4°
2037-10-07 Wed	100	—	unknown	20:25–05:55 (good, 9.5 h)	79.2° 01:50	9.48	2%	138.0°
2037-10-08 Thu	100	—	unknown	20:25–05:55 (good, 9.5 h)	79.2° 01:45	9.52	0%	148.8°
2037-10-09 Fri	100	—	unknown	20:25–06:00 (good, 9.58 h)	79.2° 01:40	9.57	1%	155.2°
2037-10-10 Sat	100	—	unknown	20:20–06:00 (good, 9.67 h)	79.1° 01:40	9.61	5%	153.8°
2037-10-11 Sun	100	—	unknown	20:20–06:00 (good, 9.67 h)	79.2° 01:35	9.66	11%	146.0°
2037-10-12 Mon	100	—	unknown	20:20–06:00 (good, 9.67 h)	79.2° 01:30	9.7	20%	135.3°
2037-10-13 Tue	100	—	unknown	20:15–06:00 (good, 9.75 h)	79.2° 01:25	9.75	29%	123.8°
2037-10-14 Wed	100	—	unknown	20:15–06:05 (good, 9.83 h)	79.2° 01:20	9.79	39%	112.2°
2037-10-15 Thu	100	—	unknown	20:15–06:05 (good, 9.83 h)	79.2° 01:20	9.84	49%	100.6°
2037-10-16 Fri	100	—	unknown	20:15–06:05 (good, 9.83 h)	79.2° 01:15	9.88	59%	89.3°
2037-10-17 Sat	100	—	unknown	20:10–06:05 (good, 9.92 h)	79.2° 01:10	9.92	68%	78.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-09-18&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.