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: 08-31 (100), 09-01 (100), 09-02 (100), 09-03 (100), 09-04 (100) — by astronomy; check the weather when the night is within four days.

2038-08-30astronomy score per night — click a bar for that night2038-09-28

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-08-30 Mon	98	—	unknown	01:25–05:10 (good, 3.75 h)	72.5° 06:30	7.5	0%	104.3°
2038-08-31 Tue	100	—	unknown	01:20–05:10 (good, 3.83 h)	72.5° 06:30	7.56	3%	118.7°
2038-09-01 Wed	100	—	unknown	01:20–05:10 (good, 3.83 h)	72.5° 06:25	7.62	9%	133.2°
2038-09-02 Thu	100	—	unknown	01:15–05:15 (good, 4.0 h)	72.5° 06:20	7.67	17%	147.6°
2038-09-03 Fri	100	—	unknown	01:10–05:15 (good, 4.08 h)	72.5° 06:15	7.73	26%	161.4°
2038-09-04 Sat	100	—	unknown	01:05–05:15 (good, 4.17 h)	72.5° 06:10	7.78	37%	172.2°
2038-09-05 Sun	100	—	unknown	01:05–05:15 (good, 4.17 h)	72.5° 06:10	7.84	48%	166.6°
2038-09-06 Mon	100	—	unknown	01:00–05:20 (good, 4.33 h)	72.5° 06:05	7.89	60%	153.9°
2038-09-07 Tue	100	—	unknown	01:00–05:20 (good, 4.33 h)	72.5° 06:00	7.95	70%	140.6°
2038-09-08 Wed	100	—	unknown	00:55–05:20 (good, 4.42 h)	72.5° 05:55	8.0	79%	127.5°
2038-09-09 Thu	100	—	unknown	00:55–05:25 (good, 4.5 h)	72.5° 05:55	8.06	87%	114.5°
2038-09-10 Fri	100	—	unknown	01:00–05:25 (good, 4.42 h)	72.5° 05:50	8.11	93%	101.7°
2038-09-11 Sat	78	—	unknown	01:30–05:25 (good, 3.92 h)	72.5° 05:45	8.16	97%	89.1°
2038-09-12 Sun	60	—	unknown	02:50–05:25 (good, 2.58 h)	72.5° 05:40	8.22	100%	76.6°
2038-09-13 Mon	45	—	unknown	04:50–05:30 (good, 0.67 h)	72.5° 05:35	8.27	100%	64.4°
2038-09-14 Tue	33	—	unknown	00:30–05:30 (marginal, 5.0 h)	72.5° 05:35	8.32	98%	52.4°
2038-09-15 Wed	24	—	unknown	00:35–05:30 (marginal, 4.92 h)	72.5° 05:30	8.38	94%	40.5°
2038-09-16 Thu	19	—	unknown	00:30–05:30 (marginal, 5.0 h)	72.5° 05:25	8.43	89%	28.9°
2038-09-17 Fri	22	—	unknown	00:15–05:35 (marginal, 5.33 h)	72.5° 05:20	8.48	83%	17.7°
2038-09-18 Sat	30	—	unknown	00:00–05:35 (marginal, 5.58 h)	72.5° 05:15	8.53	75%	8.4°
2038-09-19 Sun	42	—	unknown	23:45–05:35 (marginal, 5.83 h)	72.5° 05:15	8.59	67%	10.2°
2038-09-20 Mon	56	—	unknown	01:40–03:50 (good, 2.17 h)	72.5° 05:10	8.64	57%	20.6°
2038-09-21 Tue	71	—	unknown	00:20–05:35 (good, 5.25 h)	72.5° 05:05	8.69	48%	32.3°
2038-09-22 Wed	84	—	unknown	23:55–05:40 (good, 5.75 h)	72.5° 05:00	8.74	38%	44.5°
2038-09-23 Thu	91	—	unknown	23:50–05:40 (good, 5.83 h)	72.5° 05:00	8.79	28%	57.2°
2038-09-24 Fri	99	—	unknown	23:50–05:40 (good, 5.83 h)	72.5° 04:55	8.84	19%	70.4°
2038-09-25 Sat	100	—	unknown	23:45–05:40 (good, 5.92 h)	72.5° 04:50	8.89	11%	84.0°
2038-09-26 Sun	100	—	unknown	23:40–05:45 (good, 6.08 h)	72.5° 04:45	8.94	5%	98.1°
2038-09-27 Mon	100	—	unknown	23:35–05:45 (good, 6.17 h)	72.5° 04:40	8.99	1%	112.5°
2038-09-28 Tue	100	—	unknown	23:30–05:45 (good, 6.25 h)	72.5° 04:40	9.04	0%	127.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-08-30&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.