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: 01-18 (100), 01-19 (100), 01-20 (100), 01-21 (100), 01-22 (100) — by astronomy; check the weather when the night is within four days.

2042-01-18astronomy score per night — click a bar for that night2042-02-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-01-18 Sat	100	—	unknown	19:00–23:20 (good, 4.33 h)	89.6° 17:15	11.15	11%	122.7°
2042-01-19 Sun	100	—	unknown	19:00–23:20 (good, 4.33 h)	89.8° 17:10	11.13	5%	112.0°
2042-01-20 Mon	100	—	unknown	19:00–23:15 (good, 4.25 h)	89.8° 17:05	11.1	1%	100.4°
2042-01-21 Tue	100	—	unknown	19:00–23:10 (good, 4.17 h)	89.6° 17:00	11.08	0%	88.4°
2042-01-22 Wed	100	—	unknown	19:05–23:05 (good, 4.0 h)	89.5° 17:00	11.05	2%	76.2°
2042-01-23 Thu	100	—	unknown	19:05–23:05 (good, 4.0 h)	89.7° 16:55	11.03	6%	64.3°
2042-01-24 Fri	94	—	unknown	19:05–23:00 (good, 3.92 h)	89.8° 16:50	11.0	13%	53.0°
2042-01-25 Sat	82	—	unknown	19:05–22:55 (good, 3.83 h)	89.7° 16:45	10.97	22%	43.3°
2042-01-26 Sun	65	—	unknown	19:10–22:35 (good, 3.42 h)	89.6° 16:40	10.94	32%	36.3°
2042-01-27 Mon	49	—	unknown	19:10–22:20 (good, 3.17 h)	89.6° 16:40	10.91	43%	33.5°
2042-01-28 Tue	36	—	unknown	19:10–19:35 (good, 0.42 h)	89.7° 16:35	10.88	55%	35.7°
2042-01-29 Wed	28	—	unknown	19:10–23:00 (marginal, 3.83 h)	89.8° 16:30	10.85	65%	41.8°
2042-01-30 Thu	25	—	unknown	19:10–22:45 (marginal, 3.58 h)	89.7° 16:25	10.82	75%	50.3°
2042-01-31 Fri	24	—	unknown	19:15–22:35 (marginal, 3.33 h)	89.5° 16:20	10.79	83%	59.9°
2042-02-01 Sat	27	—	unknown	19:15–22:35 (marginal, 3.33 h)	89.6° 16:20	10.75	90%	70.1°
2042-02-02 Sun	32	—	unknown	19:15–19:40 (good, 0.42 h)	89.8° 16:15	10.72	95%	80.5°
2042-02-03 Mon	39	—	unknown	19:15–20:40 (good, 1.42 h)	89.8° 16:10	10.69	98%	90.9°
2042-02-04 Tue	46	—	unknown	19:20–21:40 (good, 2.33 h)	89.6° 16:05	10.65	100%	101.2°
2042-02-05 Wed	53	—	unknown	19:20–21:50 (good, 2.5 h)	89.5° 16:05	10.62	99%	111.1°
2042-02-06 Thu	59	—	unknown	19:20–21:55 (good, 2.58 h)	89.7° 16:00	10.58	97%	120.6°
2042-02-07 Fri	65	—	unknown	19:20–21:55 (good, 2.58 h)	89.8° 15:55	10.55	93%	129.4°
2042-02-08 Sat	66	—	unknown	19:20–21:50 (good, 2.5 h)	89.7° 15:50	10.51	87%	137.2°
2042-02-09 Sun	63	—	unknown	19:25–21:55 (good, 2.5 h)	89.6° 15:45	10.47	80%	143.1°
2042-02-10 Mon	62	—	unknown	19:25–21:50 (good, 2.42 h)	89.6° 15:45	10.44	72%	146.3°
2042-02-11 Tue	59	—	unknown	19:25–21:50 (good, 2.42 h)	89.7° 15:40	10.4	63%	146.0°
2042-02-12 Wed	57	—	unknown	19:25–21:45 (good, 2.33 h)	89.8° 15:35	10.36	54%	142.1°
2042-02-13 Thu	55	—	unknown	19:30–21:40 (good, 2.17 h)	89.7° 15:30	10.32	44%	135.4°
2042-02-14 Fri	53	—	unknown	19:30–21:35 (good, 2.08 h)	89.5° 15:25	10.28	34%	126.7°
2042-02-15 Sat	50	—	unknown	19:30–21:30 (good, 2.0 h)	89.6° 15:25	10.24	24%	116.7°
2042-02-16 Sun	49	—	unknown	19:30–21:30 (good, 2.0 h)	89.8° 15:20	10.2	15%	105.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-01-18&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.