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: 11-17 (100), 11-18 (100), 11-19 (100), 11-20 (100), 11-21 (100) — by astronomy; check the weather when the night is within four days.

2027-11-16astronomy score per night — click a bar for that night2027-12-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-11-16 Tue	91	—	unknown	18:40–21:40 (good, 3.0 h)	79.1° 22:15	10.98	90%	58.0°
2027-11-17 Wed	100	—	unknown	18:40–01:05 (good, 6.42 h)	79.1° 22:10	11.01	83%	71.7°
2027-11-18 Thu	100	—	unknown	18:40–02:50 (good, 8.17 h)	79.1° 22:05	11.04	73%	85.5°
2027-11-19 Fri	100	—	unknown	18:35–03:15 (good, 8.67 h)	79.1° 22:00	11.06	63%	99.2°
2027-11-20 Sat	100	—	unknown	18:35–03:20 (good, 8.75 h)	79.1° 22:00	11.09	51%	112.9°
2027-11-21 Sun	100	—	unknown	18:35–03:20 (good, 8.75 h)	79.1° 21:55	11.11	40%	126.4°
2027-11-22 Mon	100	—	unknown	18:35–03:20 (good, 8.75 h)	79.1° 21:50	11.14	29%	139.5°
2027-11-23 Tue	100	—	unknown	18:35–03:20 (good, 8.75 h)	79.1° 21:45	11.16	20%	151.9°
2027-11-24 Wed	100	—	unknown	18:35–03:15 (good, 8.67 h)	79.1° 21:40	11.19	12%	162.2°
2027-11-25 Thu	100	—	unknown	18:35–03:10 (good, 8.58 h)	79.1° 21:40	11.21	6%	165.4°
2027-11-26 Fri	100	—	unknown	18:35–03:05 (good, 8.5 h)	79.1° 21:35	11.23	2%	158.5°
2027-11-27 Sat	100	—	unknown	18:35–03:05 (good, 8.5 h)	79.1° 21:30	11.25	0%	147.6°
2027-11-28 Sun	100	—	unknown	18:35–03:00 (good, 8.42 h)	79.1° 21:25	11.27	1%	135.8°
2027-11-29 Mon	100	—	unknown	18:35–02:55 (good, 8.33 h)	79.1° 21:25	11.29	3%	123.8°
2027-11-30 Tue	100	—	unknown	18:35–02:50 (good, 8.25 h)	79.1° 21:20	11.31	8%	111.9°
2027-12-01 Wed	100	—	unknown	18:35–02:45 (good, 8.17 h)	79.1° 21:15	11.33	14%	100.1°
2027-12-02 Thu	100	—	unknown	18:35–02:45 (good, 8.17 h)	79.1° 21:10	11.34	21%	88.5°
2027-12-03 Fri	100	—	unknown	18:35–02:40 (good, 8.08 h)	79.1° 21:05	11.36	29%	77.0°
2027-12-04 Sat	100	—	unknown	18:35–02:35 (good, 8.0 h)	79.1° 21:05	11.38	38%	65.6°
2027-12-05 Sun	97	—	unknown	18:35–02:30 (good, 7.92 h)	79.1° 21:00	11.39	47%	54.2°
2027-12-06 Mon	89	—	unknown	18:35–02:25 (good, 7.83 h)	79.1° 20:55	11.4	57%	42.9°
2027-12-07 Tue	81	—	unknown	22:40–02:25 (good, 3.75 h)	79.1° 20:50	11.42	66%	31.8°
2027-12-08 Wed	52	—	unknown	18:35–02:45 (marginal, 8.17 h)	79.1° 20:45	11.43	75%	21.5°
2027-12-09 Thu	36	—	unknown	18:35–02:25 (marginal, 7.83 h)	79.1° 20:45	11.44	83%	14.6°
2027-12-10 Fri	25	—	unknown	18:35–02:00 (marginal, 7.42 h)	79.1° 20:40	11.45	90%	17.2°
2027-12-11 Sat	21	—	unknown	18:35–20:05 (marginal, 1.5 h)	79.1° 20:35	11.46	96%	27.1°
2027-12-12 Sun	30	—	unknown	18:35–22:20 (marginal, 3.75 h)	79.1° 20:30	11.47	99%	39.6°
2027-12-13 Mon	49	—	unknown	18:35–01:35 (marginal, 7.0 h)	79.1° 20:30	11.48	100%	53.1°
2027-12-14 Tue	70	—	unknown	18:35–20:50 (good, 2.25 h)	79.1° 20:25	11.48	98%	67.0°
2027-12-15 Wed	100	—	unknown	18:35–23:40 (good, 5.08 h)	79.1° 20:20	11.49	93%	81.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-11-16&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.