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: 08-15 (60), 08-14 (58), 08-13 (57), 08-12 (55), 08-11 (51) — by astronomy; check the weather when the night is within four days.

2043-07-17astronomy score per night — click a bar for that night2043-08-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-07-17 Fri	4	—	unknown	04:20–04:50 (marginal, 0.5 h)	72.6° 09:25	5.08	84%	172.3°
2043-07-18 Sat	6	—	unknown	04:15–04:50 (marginal, 0.58 h)	72.5° 09:20	5.13	90%	160.3°
2043-07-19 Sun	7	—	unknown	04:10–04:55 (marginal, 0.75 h)	72.5° 09:20	5.17	95%	148.2°
2043-07-20 Mon	7	—	unknown	04:15–04:55 (marginal, 0.67 h)	72.6° 09:15	5.22	98%	135.9°
2043-07-21 Tue	9	—	unknown	03:35–04:10 (marginal, 0.58 h)	72.6° 09:10	5.27	100%	123.3°
2043-07-22 Wed	8	—	unknown	03:35–04:10 (marginal, 0.58 h)	72.6° 09:05	5.32	99%	110.5°
2043-07-23 Thu	8	—	unknown	03:30–04:10 (marginal, 0.67 h)	72.5° 09:05	5.37	96%	97.5°
2043-07-24 Fri	8	—	unknown	03:30–04:15 (marginal, 0.75 h)	72.6° 09:00	5.42	92%	84.3°
2043-07-25 Sat	7	—	unknown	03:30–04:15 (marginal, 0.75 h)	72.6° 08:55	5.47	85%	70.8°
2043-07-26 Sun	7	—	unknown	03:30–04:15 (marginal, 0.75 h)	72.6° 08:50	5.52	76%	57.2°
2043-07-27 Mon	7	—	unknown	03:25–04:15 (marginal, 0.83 h)	72.5° 08:45	5.57	66%	43.4°
2043-07-28 Tue	9	—	unknown	03:20–04:20 (marginal, 1.0 h)	72.5° 08:45	5.62	55%	29.4°
2043-07-29 Wed	13	—	unknown	03:05–04:20 (marginal, 1.25 h)	72.6° 08:40	5.68	43%	15.3°
2043-07-30 Thu	17	—	unknown	03:50–04:20 (good, 0.5 h)	72.6° 08:35	5.73	32%	1.1°
2043-07-31 Fri	22	—	unknown	03:35–04:25 (good, 0.83 h)	72.6° 08:30	5.79	22%	13.3°
2043-08-01 Sat	27	—	unknown	03:25–04:25 (good, 1.0 h)	72.5° 08:25	5.84	13%	27.7°
2043-08-02 Sun	31	—	unknown	03:15–04:25 (good, 1.17 h)	72.5° 08:25	5.9	6%	42.1°
2043-08-03 Mon	35	—	unknown	03:15–04:30 (good, 1.25 h)	72.6° 08:20	5.95	2%	56.3°
2043-08-04 Tue	37	—	unknown	03:10–04:30 (good, 1.33 h)	72.6° 08:15	6.01	0%	70.4°
2043-08-05 Wed	38	—	unknown	03:05–04:30 (good, 1.42 h)	72.6° 08:10	6.06	1%	84.2°
2043-08-06 Thu	41	—	unknown	03:00–04:35 (good, 1.58 h)	72.5° 08:10	6.12	4%	97.6°
2043-08-07 Fri	43	—	unknown	03:00–04:35 (good, 1.58 h)	72.6° 08:05	6.18	9%	110.7°
2043-08-08 Sat	45	—	unknown	02:55–04:35 (good, 1.67 h)	72.6° 08:00	6.23	16%	123.5°
2043-08-09 Sun	48	—	unknown	02:50–04:40 (good, 1.83 h)	72.6° 07:55	6.29	24%	135.9°
2043-08-10 Mon	49	—	unknown	02:45–04:40 (good, 1.92 h)	72.5° 07:50	6.35	33%	148.1°
2043-08-11 Tue	51	—	unknown	02:40–04:40 (good, 2.0 h)	72.5° 07:50	6.41	42%	160.1°
2043-08-12 Wed	55	—	unknown	02:40–04:45 (good, 2.08 h)	72.6° 07:45	6.46	51%	171.9°
2043-08-13 Thu	57	—	unknown	02:35–04:45 (good, 2.17 h)	72.6° 07:40	6.52	61%	176.2°
2043-08-14 Fri	58	—	unknown	02:30–04:45 (good, 2.25 h)	72.6° 07:35	6.58	70%	164.3°
2043-08-15 Sat	60	—	unknown	02:25–04:45 (good, 2.33 h)	72.5° 07:30	6.64	78%	152.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-07-17&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.