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: 06-15 (36), 06-14 (35), 06-13 (33), 06-12 (32), 06-11 (31) — by astronomy; check the weather when the night is within four days.

2043-05-17astronomy score per night — click a bar for that night2043-06-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-05-17 Sun	6	—	unknown	04:20–04:50 (marginal, 0.5 h)	89.5° 10:25	5.48	70%	130.6°
2043-05-18 Mon	7	—	unknown	04:15–04:50 (marginal, 0.58 h)	89.7° 10:20	5.43	79%	138.8°
2043-05-19 Tue	6	—	unknown	04:10–04:45 (marginal, 0.58 h)	89.8° 10:15	5.38	86%	145.0°
2043-05-20 Wed	7	—	unknown	04:15–04:45 (marginal, 0.5 h)	89.8° 10:10	5.33	92%	148.3°
2043-05-21 Thu	7	—	unknown	03:30–04:00 (marginal, 0.5 h)	89.6° 10:05	5.28	96%	147.7°
2043-05-22 Fri	7	—	unknown	03:25–03:55 (marginal, 0.5 h)	89.6° 10:05	5.23	99%	143.5°
2043-05-23 Sat	8	—	unknown	03:20–03:55 (marginal, 0.58 h)	89.7° 10:00	5.18	100%	136.8°
2043-05-24 Sun	8	—	unknown	03:20–03:55 (marginal, 0.58 h)	89.8° 09:55	5.13	99%	128.4°
2043-05-25 Mon	9	—	unknown	03:15–03:55 (marginal, 0.67 h)	89.7° 09:50	5.09	96%	119.1°
2043-05-26 Tue	9	—	unknown	03:10–03:50 (marginal, 0.67 h)	89.5° 09:45	5.04	92%	109.2°
2043-05-27 Wed	9	—	unknown	03:05–03:50 (marginal, 0.75 h)	89.6° 09:45	5.0	86%	98.9°
2043-05-28 Thu	9	—	unknown	03:00–03:50 (marginal, 0.83 h)	89.8° 09:40	4.96	78%	88.3°
2043-05-29 Fri	9	—	unknown	03:00–03:50 (marginal, 0.83 h)	89.8° 09:35	4.92	69%	77.5°
2043-05-30 Sat	10	—	unknown	02:55–03:45 (marginal, 0.83 h)	89.7° 09:30	4.88	59%	66.7°
2043-05-31 Sun	11	—	unknown	02:50–04:35 (marginal, 1.75 h)	89.5° 09:30	4.84	49%	56.0°
2043-06-01 Mon	13	—	unknown	03:35–03:45 (good, 0.17 h)	89.7° 09:25	4.8	38%	45.9°
2043-06-02 Tue	16	—	unknown	03:30–03:45 (good, 0.25 h)	89.8° 09:20	4.76	27%	37.3°
2043-06-03 Wed	19	—	unknown	03:10–03:45 (good, 0.58 h)	89.8° 09:15	4.73	17%	32.0°
2043-06-04 Thu	23	—	unknown	03:10–03:45 (good, 0.58 h)	89.6° 09:10	4.7	9%	32.3°
2043-06-05 Fri	24	—	unknown	03:05–03:40 (good, 0.58 h)	89.6° 09:10	4.67	4%	38.2°
2043-06-06 Sat	25	—	unknown	03:00–03:40 (good, 0.67 h)	89.7° 09:05	4.64	1%	47.8°
2043-06-07 Sun	25	—	unknown	02:55–03:40 (good, 0.75 h)	89.8° 09:00	4.61	0%	59.3°
2043-06-08 Mon	27	—	unknown	02:50–03:40 (good, 0.83 h)	89.7° 08:55	4.58	4%	71.4°
2043-06-09 Tue	28	—	unknown	02:50–03:40 (good, 0.83 h)	89.5° 08:50	4.56	9%	83.7°
2043-06-10 Wed	30	—	unknown	02:45–03:40 (good, 0.92 h)	89.6° 08:50	4.54	16%	95.7°
2043-06-11 Thu	31	—	unknown	02:40–03:40 (good, 1.0 h)	89.8° 08:45	4.52	25%	107.3°
2043-06-12 Fri	32	—	unknown	02:35–03:40 (good, 1.08 h)	89.8° 08:40	4.5	35%	118.1°
2043-06-13 Sat	33	—	unknown	02:35–03:40 (good, 1.08 h)	89.7° 08:35	4.48	45%	128.1°
2043-06-14 Sun	35	—	unknown	02:30–03:40 (good, 1.17 h)	89.5° 08:35	4.47	55%	136.9°
2043-06-15 Mon	36	—	unknown	02:25–03:40 (good, 1.25 h)	89.7° 08:30	4.45	64%	143.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-05-17&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.