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: 07-14 (91), 07-15 (91), 07-13 (89), 07-12 (88), 07-11 (87) — by astronomy; check the weather when the night is within four days.

2027-06-27astronomy score per night — click a bar for that night2027-07-26

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-06-27 Sun	33	—	unknown	02:00–03:40 (good, 1.67 h)	89.7° 07:40	4.46	43%	31.3°
2027-06-28 Mon	41	—	unknown	01:50–03:40 (good, 1.83 h)	89.5° 07:35	4.48	32%	28.3°
2027-06-29 Tue	49	—	unknown	01:30–03:40 (good, 2.17 h)	89.6° 07:35	4.49	23%	30.7°
2027-06-30 Wed	56	—	unknown	01:25–03:45 (good, 2.33 h)	89.7° 07:30	4.51	14%	37.9°
2027-07-01 Thu	63	—	unknown	01:20–03:45 (good, 2.42 h)	89.7° 07:25	4.53	7%	48.1°
2027-07-02 Fri	65	—	unknown	01:20–03:45 (good, 2.42 h)	89.6° 07:20	4.55	2%	59.9°
2027-07-03 Sat	67	—	unknown	01:15–03:45 (good, 2.5 h)	89.5° 07:15	4.58	0%	72.8°
2027-07-04 Sun	70	—	unknown	01:10–03:45 (good, 2.58 h)	89.6° 07:15	4.6	1%	86.0°
2027-07-05 Mon	71	—	unknown	01:05–03:45 (good, 2.67 h)	89.7° 07:10	4.63	5%	99.4°
2027-07-06 Tue	75	—	unknown	01:00–03:50 (good, 2.83 h)	89.7° 07:05	4.66	11%	112.4°
2027-07-07 Wed	77	—	unknown	01:00–03:50 (good, 2.83 h)	89.6° 07:00	4.69	20%	124.7°
2027-07-08 Thu	79	—	unknown	00:55–03:50 (good, 2.92 h)	89.5° 07:00	4.72	30%	135.9°
2027-07-09 Fri	81	—	unknown	00:50–03:50 (good, 3.0 h)	89.7° 06:55	4.76	41%	145.0°
2027-07-10 Sat	85	—	unknown	00:45–03:55 (good, 3.17 h)	89.7° 06:50	4.79	52%	150.7°
2027-07-11 Sun	87	—	unknown	00:45–03:55 (good, 3.17 h)	89.7° 06:45	4.83	62%	151.4°
2027-07-12 Mon	88	—	unknown	00:45–03:55 (good, 3.17 h)	89.5° 06:40	4.87	72%	147.0°
2027-07-13 Tue	89	—	unknown	00:40–03:55 (good, 3.25 h)	89.6° 06:40	4.9	80%	139.5°
2027-07-14 Wed	91	—	unknown	00:40–04:00 (good, 3.33 h)	89.7° 06:35	4.95	88%	130.5°
2027-07-15 Thu	91	—	unknown	00:35–04:00 (good, 3.42 h)	89.7° 06:30	4.99	93%	120.6°
2027-07-16 Fri	76	—	unknown	00:40–04:00 (good, 3.33 h)	89.6° 06:25	5.03	97%	110.4°
2027-07-17 Sat	66	—	unknown	00:45–04:00 (good, 3.25 h)	89.5° 06:20	5.07	100%	100.0°
2027-07-18 Sun	58	—	unknown	01:05–04:05 (good, 3.0 h)	89.6° 06:20	5.12	100%	89.6°
2027-07-19 Mon	48	—	unknown	02:10–04:05 (good, 1.92 h)	89.7° 06:15	5.17	98%	79.2°
2027-07-20 Tue	41	—	unknown	03:20–04:05 (good, 0.75 h)	89.7° 06:10	5.21	95%	68.9°
2027-07-21 Wed	36	—	unknown	23:40–04:10 (marginal, 4.5 h)	89.6° 06:05	5.26	91%	58.7°
2027-07-22 Thu	34	—	unknown	23:35–04:10 (marginal, 4.58 h)	89.5° 06:05	5.31	84%	49.0°
2027-07-23 Fri	34	—	unknown	23:25–04:10 (marginal, 4.75 h)	89.6° 06:00	5.36	77%	40.1°
2027-07-24 Sat	39	—	unknown	23:20–04:15 (marginal, 4.92 h)	89.7° 05:55	5.41	68%	32.8°
2027-07-25 Sun	50	—	unknown	00:50–04:00 (good, 3.17 h)	89.7° 05:50	5.46	58%	28.6°
2027-07-26 Mon	69	—	unknown	23:45–04:15 (good, 4.5 h)	89.5° 05:45	5.51	48%	29.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-06-27&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.