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.

2030-07-03astronomy score per night — click a bar for that night2030-08-01

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-07-03 Wed	68	—	unknown	01:15–03:45 (good, 2.5 h)	89.6° 07:15	4.58	9%	108.1°
2030-07-04 Thu	70	—	unknown	01:10–03:45 (good, 2.58 h)	89.5° 07:15	4.61	16%	118.9°
2030-07-05 Fri	74	—	unknown	01:05–03:50 (good, 2.75 h)	89.6° 07:10	4.64	24%	129.3°
2030-07-06 Sat	75	—	unknown	01:00–03:50 (good, 2.83 h)	89.7° 07:05	4.67	34%	138.9°
2030-07-07 Sun	77	—	unknown	00:55–03:50 (good, 2.92 h)	89.7° 07:00	4.7	44%	146.6°
2030-07-08 Mon	79	—	unknown	00:55–03:50 (good, 2.92 h)	89.6° 06:55	4.73	55%	150.5°
2030-07-09 Tue	81	—	unknown	00:55–03:50 (good, 2.92 h)	89.5° 06:55	4.77	66%	148.7°
2030-07-10 Wed	84	—	unknown	00:55–03:55 (good, 3.0 h)	89.7° 06:50	4.8	77%	141.8°
2030-07-11 Thu	83	—	unknown	00:50–03:55 (good, 3.08 h)	89.7° 06:45	4.84	86%	131.7°
2030-07-12 Fri	76	—	unknown	00:50–03:55 (good, 3.08 h)	89.7° 06:40	4.88	93%	119.9°
2030-07-13 Sat	67	—	unknown	00:55–03:55 (good, 3.0 h)	89.5° 06:35	4.92	98%	107.4°
2030-07-14 Sun	56	—	unknown	01:00–04:00 (good, 3.0 h)	89.6° 06:35	4.96	100%	94.6°
2030-07-15 Mon	46	—	unknown	02:20–04:00 (good, 1.67 h)	89.7° 06:30	5.0	99%	81.9°
2030-07-16 Tue	37	—	unknown	03:40–04:00 (good, 0.33 h)	89.7° 06:25	5.04	95%	69.6°
2030-07-17 Wed	33	—	unknown	23:55–04:05 (marginal, 4.17 h)	89.6° 06:20	5.09	89%	58.1°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-07-03&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.