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: 07-21 (100), 07-22 (100), 07-23 (100), 07-24 (100), 07-25 (100) — by astronomy; check the weather when the night is within four days.

2042-07-21astronomy score per night — click a bar for that night2042-08-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-07-21 Mon	100	—	unknown	00:00–04:10 (good, 4.17 h)	89.7° 06:05	5.28	21%	131.9°
2042-07-22 Tue	100	—	unknown	00:00–04:10 (good, 4.17 h)	89.6° 06:00	5.33	29%	139.4°
2042-07-23 Wed	100	—	unknown	23:55–04:10 (good, 4.25 h)	89.6° 06:00	5.38	38%	144.9°
2042-07-24 Thu	100	—	unknown	23:55–04:15 (good, 4.33 h)	89.8° 05:55	5.43	47%	147.3°
2042-07-25 Fri	100	—	unknown	23:50–04:15 (good, 4.42 h)	89.8° 05:50	5.48	57%	146.0°
2042-07-26 Sat	100	—	unknown	23:50–04:15 (good, 4.42 h)	89.7° 05:45	5.53	66%	141.3°
2042-07-27 Sun	100	—	unknown	23:45–04:20 (good, 4.58 h)	89.5° 05:40	5.58	75%	134.0°
2042-07-28 Mon	100	—	unknown	23:45–04:20 (good, 4.58 h)	89.7° 05:40	5.64	84%	125.0°
2042-07-29 Tue	100	—	unknown	23:45–04:20 (good, 4.58 h)	89.8° 05:35	5.69	90%	114.8°
2042-07-30 Wed	100	—	unknown	23:45–04:25 (good, 4.67 h)	89.8° 05:30	5.74	96%	103.8°
2042-07-31 Thu	80	—	unknown	23:55–04:25 (good, 4.5 h)	89.6° 05:25	5.8	99%	92.3°
2042-08-01 Fri	67	—	unknown	00:55–04:25 (good, 3.5 h)	89.5° 05:25	5.85	100%	80.5°
2042-08-02 Sat	54	—	unknown	02:25–04:25 (good, 2.0 h)	89.7° 05:20	5.91	98%	68.6°
2042-08-03 Sun	44	—	unknown	22:45–04:30 (marginal, 5.75 h)	89.8° 05:15	5.97	93%	57.1°
2042-08-04 Mon	41	—	unknown	22:40–04:30 (marginal, 5.83 h)	89.7° 05:10	6.02	86%	46.5°
2042-08-05 Tue	45	—	unknown	22:30–04:30 (marginal, 6.0 h)	89.6° 05:05	6.08	77%	38.0°
2042-08-06 Wed	67	—	unknown	23:00–23:20 (good, 0.33 h)	89.6° 05:05	6.13	67%	33.1°
2042-08-07 Thu	82	—	unknown	22:55–04:35 (good, 5.67 h)	89.8° 05:00	6.19	56%	33.4°
2042-08-08 Fri	85	—	unknown	22:50–04:35 (good, 5.75 h)	89.8° 04:55	6.25	44%	38.5°
2042-08-09 Sat	90	—	unknown	22:45–04:40 (good, 5.92 h)	89.7° 04:50	6.3	34%	46.8°
2042-08-10 Sun	96	—	unknown	22:45–04:40 (good, 5.92 h)	89.5° 04:45	6.36	24%	56.7°
2042-08-11 Mon	100	—	unknown	22:40–04:40 (good, 6.0 h)	89.7° 04:45	6.42	15%	67.3°
2042-08-12 Tue	100	—	unknown	22:35–04:45 (good, 6.17 h)	89.8° 04:40	6.48	8%	78.1°
2042-08-13 Wed	100	—	unknown	22:30–04:45 (good, 6.25 h)	89.8° 04:35	6.53	4%	89.0°
2042-08-14 Thu	100	—	unknown	22:30–04:45 (good, 6.25 h)	89.6° 04:30	6.59	1%	99.8°
2042-08-15 Fri	100	—	unknown	22:25–04:50 (good, 6.42 h)	89.5° 04:30	6.65	0%	110.2°
2042-08-16 Sat	100	—	unknown	22:20–04:50 (good, 6.5 h)	89.7° 04:25	6.71	2%	120.1°
2042-08-17 Sun	100	—	unknown	22:15–04:50 (good, 6.58 h)	89.8° 04:20	6.76	5%	129.3°
2042-08-18 Mon	100	—	unknown	22:10–04:50 (good, 6.67 h)	89.7° 04:15	6.82	9%	137.4°
2042-08-19 Tue	100	—	unknown	22:10–04:55 (good, 6.75 h)	89.6° 04:10	6.88	16%	143.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-07-21&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.