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: 06-06 (20), 06-01 (19), 06-02 (19), 06-03 (19), 06-04 (19) — by astronomy; check the weather when the night is within four days.

2039-05-11astronomy score per night — click a bar for that night2039-06-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-05-11 Wed	2	—	unknown	04:10–04:15 (marginal, 0.08 h)	89.7° 10:45	5.8	83%	106.1°
2039-05-12 Thu	2	—	unknown	04:05–04:10 (marginal, 0.08 h)	89.5° 10:40	5.75	74%	94.8°
2039-05-13 Fri	3	—	unknown	04:00–04:10 (marginal, 0.17 h)	89.6° 10:40	5.69	63%	83.8°
2039-05-14 Sat	3	—	unknown	03:55–04:10 (marginal, 0.25 h)	89.8° 10:35	5.64	52%	73.2°
2039-05-15 Sun	3	—	unknown	03:55–04:05 (marginal, 0.17 h)	89.8° 10:30	5.59	42%	63.3°
2039-05-16 Mon	4	—	unknown	03:50–04:05 (marginal, 0.25 h)	89.7° 10:25	5.53	32%	54.3°
2039-05-17 Tue	6	—	unknown	03:45–04:05 (marginal, 0.33 h)	89.5° 10:25	5.48	23%	46.7°
2039-05-18 Wed	7	—	unknown	04:15–04:50 (marginal, 0.58 h)	89.7° 10:20	5.43	15%	41.0°
2039-05-19 Thu	6	—	unknown	04:10–04:45 (marginal, 0.58 h)	89.8° 10:15	5.38	9%	37.9°
2039-05-20 Fri	7	—	unknown	04:05–04:45 (marginal, 0.67 h)	89.7° 10:10	5.33	4%	38.0°
2039-05-21 Sat	8	—	unknown	04:05–04:45 (marginal, 0.67 h)	89.6° 10:05	5.28	1%	41.1°
2039-05-22 Sun	9	—	unknown	04:00–04:45 (marginal, 0.75 h)	89.6° 10:05	5.23	0%	46.6°
2039-05-23 Mon	10	—	unknown	03:20–04:45 (marginal, 1.42 h)	89.7° 10:00	5.18	1%	53.8°
2039-05-24 Tue	10	—	unknown	03:50–03:55 (good, 0.08 h)	89.8° 09:55	5.13	3%	62.0°
2039-05-25 Wed	11	—	unknown	03:45–03:55 (good, 0.17 h)	89.7° 09:50	5.09	7%	70.8°
2039-05-26 Thu	12	—	unknown	03:45–03:50 (good, 0.08 h)	89.5° 09:45	5.04	13%	80.1°
2039-05-27 Fri	13	—	unknown	03:40–03:50 (good, 0.17 h)	89.6° 09:45	5.0	20%	89.7°
2039-05-28 Sat	15	—	unknown	03:35–03:50 (good, 0.25 h)	89.8° 09:40	4.96	28%	99.4°
2039-05-29 Sun	15	—	unknown	03:30–03:50 (good, 0.33 h)	89.8° 09:35	4.92	38%	109.1°
2039-05-30 Mon	15	—	unknown	03:30–03:45 (good, 0.25 h)	89.7° 09:30	4.88	48%	118.7°
2039-05-31 Tue	17	—	unknown	03:25–03:45 (good, 0.33 h)	89.5° 09:25	4.84	59%	127.7°
2039-06-01 Wed	19	—	unknown	03:20–03:45 (good, 0.42 h)	89.7° 09:25	4.8	69%	135.5°
2039-06-02 Thu	19	—	unknown	03:25–03:45 (good, 0.33 h)	89.8° 09:20	4.77	79%	140.9°
2039-06-03 Fri	19	—	unknown	03:20–03:45 (good, 0.42 h)	89.8° 09:15	4.73	88%	142.3°
2039-06-04 Sat	19	—	unknown	03:20–03:45 (good, 0.42 h)	89.6° 09:10	4.7	95%	139.1°
2039-06-05 Sun	19	—	unknown	03:15–03:40 (good, 0.42 h)	89.5° 09:10	4.67	99%	131.8°
2039-06-06 Mon	20	—	unknown	03:10–03:40 (good, 0.5 h)	89.7° 09:05	4.64	100%	122.0°
2039-06-07 Tue	18	—	unknown	03:15–03:40 (good, 0.42 h)	89.8° 09:00	4.61	98%	110.9°
2039-06-08 Wed	17	—	unknown	03:15–03:40 (good, 0.42 h)	89.7° 08:55	4.58	93%	99.4°
2039-06-09 Thu	17	—	unknown	03:15–03:40 (good, 0.42 h)	89.6° 08:50	4.56	86%	87.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-05-11&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.