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 V1057 Cyg: 09-26 (100), 09-27 (100), 09-28 (100), 09-29 (100), 09-30 (100) — by astronomy; check the weather when the night is within four days.

2038-09-26astronomy score per night — click a bar for that night2038-10-25

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-09-26 Sun	100	—	unknown	20:45–04:20 (good, 7.58 h)	87.3° 22:00	8.94	5%	118.1°
2038-09-27 Mon	100	—	unknown	20:45–04:15 (good, 7.5 h)	87.3° 21:55	8.99	1%	116.8°
2038-09-28 Tue	100	—	unknown	20:45–04:10 (good, 7.42 h)	87.3° 21:50	9.04	0%	113.5°
2038-09-29 Wed	100	—	unknown	20:40–04:05 (good, 7.42 h)	87.3° 21:45	9.09	2%	108.6°
2038-09-30 Thu	100	—	unknown	20:40–04:05 (good, 7.42 h)	87.3° 21:45	9.14	7%	102.6°
2038-10-01 Fri	100	—	unknown	20:40–04:00 (good, 7.33 h)	87.3° 21:40	9.18	14%	95.9°
2038-10-02 Sat	100	—	unknown	20:35–03:55 (good, 7.33 h)	87.3° 21:35	9.23	23%	89.0°
2038-10-03 Sun	100	—	unknown	20:35–03:50 (good, 7.25 h)	87.3° 21:30	9.28	34%	82.4°
2038-10-04 Mon	100	—	unknown	20:35–03:45 (good, 7.17 h)	87.3° 21:25	9.33	45%	76.3°
2038-10-05 Tue	100	—	unknown	20:30–03:45 (good, 7.25 h)	87.3° 21:25	9.37	56%	71.0°
2038-10-06 Wed	92	—	unknown	20:30–03:40 (good, 7.17 h)	87.3° 21:20	9.42	66%	66.7°
2038-10-07 Thu	85	—	unknown	20:25–03:35 (good, 7.17 h)	87.3° 21:15	9.47	75%	63.7°
2038-10-08 Fri	66	—	unknown	20:25–02:50 (good, 6.42 h)	87.3° 21:10	9.51	83%	62.2°
2038-10-09 Sat	63	—	unknown	20:25–22:00 (good, 1.58 h)	87.2° 21:05	9.56	90%	62.0°
2038-10-10 Sun	63	—	unknown	20:25–21:15 (good, 0.83 h)	87.3° 21:05	9.6	95%	63.2°
2038-10-11 Mon	64	—	unknown	20:20–21:25 (good, 1.08 h)	87.3° 21:00	9.65	98%	65.7°
2038-10-12 Tue	67	—	unknown	20:20–22:05 (good, 1.75 h)	87.3° 20:55	9.69	100%	69.3°
2038-10-13 Wed	71	—	unknown	20:20–23:10 (good, 2.83 h)	87.3° 20:50	9.74	99%	73.6°
2038-10-14 Thu	76	—	unknown	20:15–00:05 (good, 3.83 h)	87.3° 20:50	9.78	97%	78.5°
2038-10-15 Fri	80	—	unknown	20:15–00:50 (good, 4.58 h)	87.3° 20:45	9.82	93%	83.8°
2038-10-16 Sat	100	—	unknown	20:15–01:35 (good, 5.33 h)	87.3° 20:40	9.87	88%	89.3°
2038-10-17 Sun	100	—	unknown	20:10–02:25 (good, 6.25 h)	87.3° 20:35	9.91	81%	94.9°
2038-10-18 Mon	100	—	unknown	20:10–02:30 (good, 6.33 h)	87.3° 20:30	9.95	73%	100.3°
2038-10-19 Tue	100	—	unknown	20:10–02:30 (good, 6.33 h)	87.3° 20:30	10.0	64%	105.5°
2038-10-20 Wed	100	—	unknown	20:05–02:35 (good, 6.5 h)	87.3° 20:25	10.04	54%	110.1°
2038-10-21 Thu	100	—	unknown	20:05–02:35 (good, 6.5 h)	87.3° 20:20	10.08	44%	113.9°
2038-10-22 Fri	100	—	unknown	20:05–02:35 (good, 6.5 h)	87.3° 20:15	10.12	34%	116.7°
2038-10-23 Sat	100	—	unknown	20:05–02:30 (good, 6.42 h)	87.2° 20:10	10.16	24%	117.9°
2038-10-24 Sun	100	—	unknown	20:00–02:30 (good, 6.5 h)	87.3° 20:10	10.2	15%	117.5°
2038-10-25 Mon	100	—	unknown	20:00–02:25 (good, 6.42 h)	87.3° 20:05	10.24	8%	115.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-09-26&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.