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 Seven Sisters: 01-23 (100), 01-24 (100), 01-25 (100), 01-26 (100), 01-27 (100) — by astronomy; check the weather when the night is within four days.

2038-01-16astronomy score per night — click a bar for that night2038-02-14

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-01-16 Sat	30	—	unknown	18:55–01:40 (marginal, 6.75 h)	72.5° 20:25	11.2	81%	9.4°
2038-01-17 Sun	22	—	unknown	19:00–01:15 (marginal, 6.25 h)	72.5° 20:20	11.18	88%	19.2°
2038-01-18 Mon	20	—	unknown	19:00–20:55 (marginal, 1.92 h)	72.5° 20:15	11.15	94%	31.5°
2038-01-19 Tue	29	—	unknown	19:00–23:50 (marginal, 4.83 h)	72.5° 20:15	11.13	98%	44.7°
2038-01-20 Wed	45	—	unknown	19:00–01:05 (marginal, 6.08 h)	72.5° 20:10	11.11	100%	58.3°
2038-01-21 Thu	68	—	unknown	19:00–21:30 (good, 2.5 h)	72.5° 20:05	11.08	99%	72.3°
2038-01-22 Fri	81	—	unknown	19:05–23:30 (good, 4.42 h)	72.5° 20:00	11.05	96%	86.5°
2038-01-23 Sat	100	—	unknown	19:05–00:45 (good, 5.67 h)	72.5° 19:55	11.03	90%	100.8°
2038-01-24 Sun	100	—	unknown	19:05–00:50 (good, 5.75 h)	72.5° 19:55	11.0	82%	115.1°
2038-01-25 Mon	100	—	unknown	19:05–00:55 (good, 5.83 h)	72.5° 19:50	10.97	72%	129.3°
2038-01-26 Tue	100	—	unknown	19:10–00:50 (good, 5.67 h)	72.5° 19:45	10.94	61%	143.3°
2038-01-27 Wed	100	—	unknown	19:10–00:50 (good, 5.67 h)	72.5° 19:40	10.91	50%	156.8°
2038-01-28 Thu	100	—	unknown	19:10–00:50 (good, 5.67 h)	72.5° 19:35	10.88	39%	168.7°
2038-01-29 Fri	100	—	unknown	19:10–00:45 (good, 5.58 h)	72.5° 19:35	10.85	28%	170.0°
2038-01-30 Sat	100	—	unknown	19:10–00:40 (good, 5.5 h)	72.5° 19:30	10.82	19%	159.0°
2038-01-31 Sun	100	—	unknown	19:15–00:35 (good, 5.33 h)	72.5° 19:25	10.79	11%	146.4°
2038-02-01 Mon	100	—	unknown	19:15–00:35 (good, 5.33 h)	72.5° 19:20	10.75	6%	133.5°
2038-02-02 Tue	100	—	unknown	19:15–00:30 (good, 5.25 h)	72.5° 19:20	10.72	2%	120.8°
2038-02-03 Wed	100	—	unknown	19:15–00:25 (good, 5.17 h)	72.5° 19:15	10.69	0%	108.2°
2038-02-04 Thu	100	—	unknown	19:20–00:20 (good, 5.0 h)	72.5° 19:10	10.65	0%	95.8°
2038-02-05 Fri	100	—	unknown	19:20–00:15 (good, 4.92 h)	72.5° 19:05	10.62	3%	83.6°
2038-02-06 Sat	100	—	unknown	19:20–00:15 (good, 4.92 h)	72.5° 19:00	10.58	7%	71.6°
2038-02-07 Sun	100	—	unknown	19:20–00:10 (good, 4.83 h)	72.5° 19:00	10.55	13%	59.7°
2038-02-08 Mon	93	—	unknown	19:20–00:05 (good, 4.75 h)	72.5° 18:55	10.51	20%	48.0°
2038-02-09 Tue	86	—	unknown	19:25–00:00 (good, 4.58 h)	72.5° 18:50	10.47	28%	36.5°
2038-02-10 Wed	74	—	unknown	19:25–23:55 (good, 4.5 h)	72.5° 18:45	10.44	36%	25.1°
2038-02-11 Thu	58	—	unknown	19:25–23:30 (good, 4.08 h)	72.5° 18:40	10.4	46%	14.4°
2038-02-12 Fri	43	—	unknown	20:35–20:45 (good, 0.17 h)	72.5° 18:40	10.36	55%	8.1°
2038-02-13 Sat	31	—	unknown	19:30–00:00 (marginal, 4.5 h)	72.5° 18:35	10.32	65%	14.8°
2038-02-14 Sun	21	—	unknown	19:30–23:40 (marginal, 4.17 h)	72.5° 18:30	10.28	74%	26.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-01-16&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.