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: 05-27 (100), 05-28 (100), 05-29 (100), 05-30 (100), 05-31 (100) — by astronomy; check the weather when the night is within four days.

2038-05-03astronomy score per night — click a bar for that night2038-06-01

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-05-03 Mon	82	—	unknown	01:20–04:25 (good, 3.08 h)	87.2° 07:35	6.24	0%	77.9°
2038-05-04 Tue	83	—	unknown	01:15–04:25 (good, 3.17 h)	87.3° 07:30	6.19	0%	83.3°
2038-05-05 Wed	86	—	unknown	01:10–04:25 (good, 3.25 h)	87.3° 07:25	6.13	2%	89.0°
2038-05-06 Thu	86	—	unknown	01:05–04:20 (good, 3.25 h)	87.3° 07:20	6.07	6%	94.7°
2038-05-07 Fri	87	—	unknown	01:00–04:20 (good, 3.33 h)	87.3° 07:15	6.01	11%	100.4°
2038-05-08 Sat	89	—	unknown	01:00–04:20 (good, 3.33 h)	87.3° 07:15	5.96	18%	105.7°
2038-05-09 Sun	89	—	unknown	00:55–04:15 (good, 3.33 h)	87.3° 07:10	5.9	27%	110.5°
2038-05-10 Mon	90	—	unknown	00:55–04:15 (good, 3.33 h)	87.3° 07:05	5.85	37%	114.4°
2038-05-11 Tue	91	—	unknown	00:50–04:15 (good, 3.42 h)	87.3° 07:00	5.79	47%	117.1°
2038-05-12 Wed	90	—	unknown	00:50–04:10 (good, 3.33 h)	87.3° 06:55	5.73	58%	118.3°
2038-05-13 Thu	89	—	unknown	00:50–04:10 (good, 3.33 h)	87.3° 06:55	5.68	69%	117.7°
2038-05-14 Fri	81	—	unknown	00:50–04:10 (good, 3.33 h)	87.3° 06:50	5.63	79%	115.3°
2038-05-15 Sat	74	—	unknown	00:50–04:05 (good, 3.25 h)	87.3° 06:45	5.57	88%	111.1°
2038-05-16 Sun	69	—	unknown	00:50–04:05 (good, 3.25 h)	87.3° 06:40	5.52	95%	105.5°
2038-05-17 Mon	62	—	unknown	00:55–04:05 (good, 3.17 h)	87.2° 06:40	5.47	99%	99.0°
2038-05-18 Tue	56	—	unknown	01:15–04:00 (good, 2.75 h)	87.3° 06:35	5.42	100%	92.0°
2038-05-19 Wed	52	—	unknown	01:25–04:00 (good, 2.58 h)	87.3° 06:30	5.37	98%	85.0°
2038-05-20 Thu	51	—	unknown	01:15–04:00 (good, 2.75 h)	87.3° 06:25	5.32	94%	78.4°
2038-05-21 Fri	54	—	unknown	00:40–04:00 (good, 3.33 h)	87.3° 06:20	5.27	87%	72.6°
2038-05-22 Sat	67	—	unknown	00:05–03:55 (good, 3.83 h)	87.3° 06:20	5.22	78%	67.8°
2038-05-23 Sun	78	—	unknown	00:00–03:55 (good, 3.92 h)	87.3° 06:15	5.17	69%	64.4°
2038-05-24 Mon	88	—	unknown	23:55–03:55 (good, 4.0 h)	87.3° 06:10	5.12	59%	62.3°
2038-05-25 Tue	95	—	unknown	23:50–03:55 (good, 4.08 h)	87.3° 06:05	5.08	49%	61.7°
2038-05-26 Wed	99	—	unknown	23:45–03:50 (good, 4.08 h)	87.3° 06:00	5.03	40%	62.6°
2038-05-27 Thu	100	—	unknown	23:45–03:50 (good, 4.08 h)	87.3° 06:00	4.99	31%	64.6°
2038-05-28 Fri	100	—	unknown	23:40–03:50 (good, 4.17 h)	87.3° 05:55	4.95	22%	67.8°
2038-05-29 Sat	100	—	unknown	23:35–03:50 (good, 4.25 h)	87.3° 05:50	4.91	15%	71.9°
2038-05-30 Sun	100	—	unknown	23:30–03:45 (good, 4.25 h)	87.3° 05:45	4.87	9%	76.6°
2038-05-31 Mon	100	—	unknown	23:30–03:45 (good, 4.25 h)	87.2° 05:45	4.83	4%	81.9°
2038-06-01 Tue	100	—	unknown	23:25–03:45 (good, 4.33 h)	87.3° 05:40	4.79	1%	87.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-05-03&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.