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: 07-26 (100), 07-27 (100), 07-28 (100), 07-29 (100), 07-30 (100) — by astronomy; check the weather when the night is within four days.

2030-07-18astronomy score per night — click a bar for that night2030-08-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-07-18 Thu	31	—	unknown	23:50–04:05 (marginal, 4.25 h)	89.5° 06:20	5.13	82%	47.5°
2030-07-19 Fri	34	—	unknown	23:40–04:05 (marginal, 4.42 h)	89.6° 06:15	5.18	73%	38.6°
2030-07-20 Sat	40	—	unknown	23:35–04:05 (marginal, 4.5 h)	89.7° 06:10	5.23	64%	32.2°
2030-07-21 Sun	52	—	unknown	00:30–04:10 (good, 3.67 h)	89.7° 06:05	5.27	54%	29.5°
2030-07-22 Mon	72	—	unknown	00:00–04:10 (good, 4.17 h)	89.6° 06:00	5.32	44%	31.2°
2030-07-23 Tue	85	—	unknown	23:55–04:10 (good, 4.25 h)	89.5° 06:00	5.37	35%	36.6°
2030-07-24 Wed	90	—	unknown	23:50–04:15 (good, 4.42 h)	89.7° 05:55	5.42	26%	44.2°
2030-07-25 Thu	95	—	unknown	23:45–04:15 (good, 4.5 h)	89.7° 05:50	5.48	18%	53.2°
2030-07-26 Fri	100	—	unknown	23:40–04:15 (good, 4.58 h)	89.7° 05:45	5.53	12%	62.9°
2030-07-27 Sat	100	—	unknown	23:40–04:20 (good, 4.67 h)	89.5° 05:40	5.58	6%	73.0°
2030-07-28 Sun	100	—	unknown	23:35–04:20 (good, 4.75 h)	89.6° 05:40	5.63	2%	83.6°
2030-07-29 Mon	100	—	unknown	23:30–04:20 (good, 4.83 h)	89.7° 05:35	5.69	0%	94.4°
2030-07-30 Tue	100	—	unknown	23:25–04:20 (good, 4.92 h)	89.7° 05:30	5.74	0%	105.3°
2030-07-31 Wed	100	—	unknown	23:25–04:25 (good, 5.0 h)	89.6° 05:25	5.79	2%	116.2°
2030-08-01 Thu	100	—	unknown	23:20–04:25 (good, 5.08 h)	89.5° 05:25	5.85	7%	126.8°
2030-08-02 Fri	100	—	unknown	23:15–04:25 (good, 5.17 h)	89.6° 05:20	5.9	13%	136.7°
2030-08-03 Sat	100	—	unknown	23:10–04:30 (good, 5.33 h)	89.7° 05:15	5.96	21%	144.9°
2030-08-04 Sun	100	—	unknown	23:05–04:30 (good, 5.42 h)	89.7° 05:10	6.02	31%	149.9°
2030-08-05 Mon	100	—	unknown	23:05–04:30 (good, 5.42 h)	89.6° 05:05	6.07	41%	149.5°
2030-08-06 Tue	100	—	unknown	23:05–04:35 (good, 5.5 h)	89.5° 05:05	6.13	53%	143.8°
2030-08-07 Wed	100	—	unknown	23:00–04:35 (good, 5.58 h)	89.7° 05:00	6.19	64%	134.7°
2030-08-08 Thu	100	—	unknown	23:00–04:35 (good, 5.58 h)	89.7° 04:55	6.24	75%	123.7°
2030-08-09 Fri	100	—	unknown	23:00–04:40 (good, 5.67 h)	89.7° 04:50	6.3	84%	111.8°
2030-08-10 Sat	100	—	unknown	23:10–04:40 (good, 5.5 h)	89.5° 04:45	6.36	92%	99.4°
2030-08-11 Sun	79	—	unknown	23:50–04:40 (good, 4.83 h)	89.6° 04:45	6.41	97%	86.9°
2030-08-12 Mon	69	—	unknown	01:30–04:45 (good, 3.25 h)	89.7° 04:40	6.47	100%	74.5°
2030-08-13 Tue	53	—	unknown	22:15–04:45 (marginal, 6.5 h)	89.7° 04:35	6.53	100%	62.7°
2030-08-14 Wed	40	—	unknown	22:10–04:45 (marginal, 6.58 h)	89.6° 04:30	6.59	97%	51.7°
2030-08-15 Thu	34	—	unknown	22:10–04:50 (marginal, 6.67 h)	89.5° 04:25	6.64	92%	41.9°
2030-08-16 Fri	37	—	unknown	22:05–04:50 (marginal, 6.75 h)	89.6° 04:25	6.7	86%	34.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-07-18&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.