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 Andromeda Galaxy: 02-04 (77), 02-05 (73), 02-06 (71), 02-07 (68), 02-08 (66) — by astronomy; check the weather when the night is within four days.

2027-02-04astronomy score per night — click a bar for that night2027-03-05

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-02-04 Thu	77	—	unknown	19:15–22:15 (good, 3.0 h)	89.5° 16:05	10.66	3%	91.8°
2027-02-05 Fri	73	—	unknown	19:20–22:10 (good, 2.83 h)	89.6° 16:05	10.63	0%	81.3°
2027-02-06 Sat	71	—	unknown	19:20–22:10 (good, 2.83 h)	89.7° 16:00	10.59	0%	70.8°
2027-02-07 Sun	68	—	unknown	19:20–22:05 (good, 2.75 h)	89.7° 15:55	10.56	2%	60.5°
2027-02-08 Mon	66	—	unknown	19:20–22:00 (good, 2.67 h)	89.6° 15:50	10.52	5%	50.5°
2027-02-09 Tue	59	—	unknown	19:25–21:55 (good, 2.5 h)	89.5° 15:50	10.49	10%	41.2°
2027-02-10 Wed	52	—	unknown	19:25–21:45 (good, 2.33 h)	89.6° 15:45	10.45	17%	33.5°
2027-02-11 Thu	42	—	unknown	19:25–21:35 (good, 2.17 h)	89.7° 15:40	10.41	25%	28.9°
2027-02-12 Fri	34	—	unknown	19:25–21:20 (good, 1.92 h)	89.7° 15:35	10.37	35%	29.3°
2027-02-13 Sat	26	—	unknown	19:25–19:55 (good, 0.5 h)	89.6° 15:30	10.33	46%	34.8°
2027-02-14 Sun	20	—	unknown	19:30–22:00 (marginal, 2.5 h)	89.5° 15:30	10.3	57%	43.7°
2027-02-15 Mon	18	—	unknown	19:30–21:50 (marginal, 2.33 h)	89.7° 15:25	10.26	68%	54.6°
2027-02-16 Tue	17	—	unknown	19:30–21:45 (marginal, 2.25 h)	89.7° 15:20	10.22	78%	66.7°
2027-02-17 Wed	19	—	unknown	19:30–21:45 (marginal, 2.25 h)	89.7° 15:15	10.18	87%	79.4°
2027-02-18 Thu	22	—	unknown	19:35–20:00 (good, 0.42 h)	89.5° 15:10	10.13	94%	92.5°
2027-02-19 Fri	27	—	unknown	19:35–20:50 (good, 1.25 h)	89.6° 15:10	10.09	98%	105.6°
2027-02-20 Sat	31	—	unknown	19:35–21:00 (good, 1.42 h)	89.7° 15:05	10.05	100%	118.3°
2027-02-21 Sun	32	—	unknown	19:35–20:55 (good, 1.33 h)	89.7° 15:00	10.01	99%	130.2°
2027-02-22 Mon	35	—	unknown	19:40–20:55 (good, 1.25 h)	89.6° 14:55	9.97	95%	140.7°
2027-02-23 Tue	35	—	unknown	19:40–21:00 (good, 1.33 h)	89.5° 14:55	9.92	89%	148.3°
2027-02-24 Wed	33	—	unknown	19:40–20:55 (good, 1.25 h)	89.6° 14:50	9.88	81%	151.5°
2027-02-25 Thu	32	—	unknown	19:40–20:55 (good, 1.25 h)	89.7° 14:45	9.84	72%	149.3°
2027-02-26 Fri	30	—	unknown	19:40–20:50 (good, 1.17 h)	89.7° 14:40	9.79	62%	143.1°
2027-02-27 Sat	28	—	unknown	19:45–20:45 (good, 1.0 h)	89.6° 14:35	9.75	53%	134.7°
2027-02-28 Sun	27	—	unknown	19:45–20:40 (good, 0.92 h)	89.5° 14:35	9.7	43%	125.3°
2027-03-01 Mon	25	—	unknown	19:45–20:40 (good, 0.92 h)	89.7° 14:30	9.66	34%	115.4°
2027-03-02 Tue	23	—	unknown	19:45–20:35 (good, 0.83 h)	89.7° 14:25	9.61	25%	105.2°
2027-03-03 Wed	22	—	unknown	19:50–20:30 (good, 0.67 h)	89.7° 14:20	9.57	18%	94.9°
2027-03-04 Thu	20	—	unknown	19:50–20:25 (good, 0.58 h)	89.5° 14:15	9.52	11%	84.4°
2027-03-05 Fri	18	—	unknown	19:50–20:20 (good, 0.5 h)	89.6° 14:15	9.47	6%	73.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-02-04&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.