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: 01-26 (98), 01-25 (97), 01-24 (96), 01-27 (96), 01-28 (93) — by astronomy; check the weather when the night is within four days.

2027-01-17astronomy score per night — click a bar for that night2027-02-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-01-17 Sun	28	—	unknown	19:00–23:35 (marginal, 4.58 h)	89.5° 17:20	11.19	72%	37.2°
2027-01-18 Mon	25	—	unknown	19:00–23:20 (marginal, 4.33 h)	89.7° 17:15	11.16	82%	47.2°
2027-01-19 Tue	28	—	unknown	19:00–23:15 (marginal, 4.25 h)	89.7° 17:10	11.14	90%	59.0°
2027-01-20 Wed	37	—	unknown	19:00–23:20 (marginal, 4.33 h)	89.6° 17:05	11.11	96%	71.8°
2027-01-21 Thu	49	—	unknown	19:00–20:45 (good, 1.75 h)	89.5° 17:00	11.09	100%	85.1°
2027-01-22 Fri	64	—	unknown	19:05–22:10 (good, 3.08 h)	89.6° 17:00	11.06	100%	98.5°
2027-01-23 Sat	80	—	unknown	19:05–22:45 (good, 3.67 h)	89.7° 16:55	11.04	97%	111.5°
2027-01-24 Sun	96	—	unknown	19:05–22:50 (good, 3.75 h)	89.7° 16:50	11.01	92%	123.9°
2027-01-25 Mon	97	—	unknown	19:05–22:45 (good, 3.67 h)	89.6° 16:45	10.98	84%	135.1°
2027-01-26 Tue	98	—	unknown	19:05–22:45 (good, 3.67 h)	89.5° 16:45	10.95	75%	144.4°
2027-01-27 Wed	96	—	unknown	19:10–22:45 (good, 3.58 h)	89.6° 16:40	10.92	65%	150.2°
2027-01-28 Thu	93	—	unknown	19:10–22:45 (good, 3.58 h)	89.7° 16:35	10.89	55%	151.3°
2027-01-29 Fri	92	—	unknown	19:10–22:40 (good, 3.5 h)	89.7° 16:30	10.86	45%	147.5°
2027-01-30 Sat	90	—	unknown	19:10–22:35 (good, 3.42 h)	89.6° 16:25	10.83	36%	140.5°
2027-01-31 Sun	86	—	unknown	19:15–22:30 (good, 3.25 h)	89.5° 16:25	10.8	27%	131.9°
2027-02-01 Mon	83	—	unknown	19:15–22:30 (good, 3.25 h)	89.7° 16:20	10.77	19%	122.4°
2027-02-02 Tue	81	—	unknown	19:15–22:25 (good, 3.17 h)	89.7° 16:15	10.73	12%	112.4°
2027-02-03 Wed	79	—	unknown	19:15–22:20 (good, 3.08 h)	89.6° 16:10	10.7	7%	102.2°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-01-17&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.