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: 07-19 (100), 07-20 (100), 07-21 (100), 07-22 (100), 07-23 (100) — by astronomy; check the weather when the night is within four days.

2039-07-19astronomy score per night — click a bar for that night2039-08-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-07-19 Tue	100	—	unknown	22:55–04:05 (good, 5.17 h)	87.3° 02:30	5.17	2%	105.1°
2039-07-20 Wed	100	—	unknown	22:55–04:05 (good, 5.17 h)	87.3° 02:25	5.22	0%	109.5°
2039-07-21 Thu	100	—	unknown	22:50–04:10 (good, 5.33 h)	87.3° 02:25	5.27	0%	113.3°
2039-07-22 Fri	100	—	unknown	22:50–04:10 (good, 5.33 h)	87.3° 02:20	5.31	3%	115.9°
2039-07-23 Sat	100	—	unknown	22:50–04:10 (good, 5.33 h)	87.3° 02:15	5.36	7%	117.4°
2039-07-24 Sun	100	—	unknown	22:50–04:15 (good, 5.42 h)	87.3° 02:10	5.41	13%	117.3°
2039-07-25 Mon	100	—	unknown	22:45–04:15 (good, 5.5 h)	87.2° 02:05	5.47	21%	115.8°
2039-07-26 Tue	100	—	unknown	22:45–04:15 (good, 5.5 h)	87.3° 02:05	5.52	30%	112.8°
2039-07-27 Wed	100	—	unknown	22:45–04:15 (good, 5.5 h)	87.3° 02:00	5.57	41%	108.4°
2039-07-28 Thu	100	—	unknown	22:40–04:20 (good, 5.67 h)	87.3° 01:55	5.62	52%	103.1°
2039-07-29 Fri	100	—	unknown	22:40–04:20 (good, 5.67 h)	87.3° 01:50	5.68	64%	97.0°
2039-07-30 Sat	100	—	unknown	22:40–04:20 (good, 5.67 h)	87.2° 01:50	5.73	74%	90.4°
2039-07-31 Sun	100	—	unknown	22:35–04:25 (good, 5.83 h)	87.3° 01:45	5.78	84%	83.7°
2039-08-01 Mon	100	—	unknown	22:35–04:25 (good, 5.83 h)	87.3° 01:40	5.84	92%	77.3°
2039-08-02 Tue	75	—	unknown	22:35–04:25 (good, 5.83 h)	87.3° 01:35	5.89	97%	71.6°
2039-08-03 Wed	68	—	unknown	22:30–04:30 (good, 6.0 h)	87.3° 01:30	5.95	100%	67.0°
2039-08-04 Thu	66	—	unknown	22:30–00:50 (good, 2.33 h)	87.3° 01:30	6.01	100%	63.9°
2039-08-05 Fri	68	—	unknown	22:30–01:00 (good, 2.5 h)	87.3° 01:25	6.06	97%	62.5°
2039-08-06 Sat	73	—	unknown	22:25–02:00 (good, 3.58 h)	87.3° 01:20	6.12	92%	62.8°
2039-08-07 Sun	100	—	unknown	22:25–04:10 (good, 5.75 h)	87.3° 01:15	6.18	85%	64.8°
2039-08-08 Mon	100	—	unknown	22:20–04:35 (good, 6.25 h)	87.2° 01:10	6.23	77%	68.0°
2039-08-09 Tue	100	—	unknown	22:20–04:40 (good, 6.33 h)	87.3° 01:10	6.29	68%	72.1°
2039-08-10 Wed	100	—	unknown	22:20–04:40 (good, 6.33 h)	87.3° 01:05	6.35	58%	76.9°
2039-08-11 Thu	100	—	unknown	22:15–04:40 (good, 6.42 h)	87.3° 01:00	6.4	49%	82.1°
2039-08-12 Fri	100	—	unknown	22:15–04:45 (good, 6.5 h)	87.3° 00:55	6.46	40%	87.5°
2039-08-13 Sat	100	—	unknown	22:15–04:45 (good, 6.5 h)	87.2° 00:55	6.52	30%	93.0°
2039-08-14 Sun	100	—	unknown	22:10–04:45 (good, 6.58 h)	87.3° 00:50	6.58	22%	98.4°
2039-08-15 Mon	100	—	unknown	22:10–04:45 (good, 6.58 h)	87.3° 00:45	6.63	15%	103.5°
2039-08-16 Tue	100	—	unknown	22:05–04:50 (good, 6.75 h)	87.3° 00:40	6.69	9%	108.2°
2039-08-17 Wed	100	—	unknown	22:05–04:50 (good, 6.75 h)	87.3° 00:35	6.75	4%	112.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-07-19&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.