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: 04-15 (64), 04-14 (60), 04-13 (54), 03-27 (48), 03-28 (48) — by astronomy; check the weather when the night is within four days.

2042-03-17astronomy score per night — click a bar for that night2042-04-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-03-17 Mon	40	—	unknown	03:20–04:55 (good, 1.58 h)	87.2° 09:35	8.87	20%	68.6°
2042-03-18 Tue	40	—	unknown	03:20–04:55 (good, 1.58 h)	87.3° 09:35	8.82	11%	64.4°
2042-03-19 Wed	42	—	unknown	03:15–04:55 (good, 1.67 h)	87.3° 09:30	8.77	5%	61.7°
2042-03-20 Thu	42	—	unknown	03:10–04:50 (good, 1.67 h)	87.3° 09:25	8.72	1%	61.1°
2042-03-21 Fri	44	—	unknown	03:05–04:50 (good, 1.75 h)	87.3° 09:20	8.66	0%	62.7°
2042-03-22 Sat	44	—	unknown	03:05–04:50 (good, 1.75 h)	87.2° 09:20	8.61	2%	66.3°
2042-03-23 Sun	44	—	unknown	03:00–04:45 (good, 1.75 h)	87.3° 09:15	8.56	7%	71.5°
2042-03-24 Mon	46	—	unknown	02:55–04:45 (good, 1.83 h)	87.3° 09:10	8.51	15%	77.6°
2042-03-25 Tue	47	—	unknown	02:50–04:45 (good, 1.92 h)	87.3° 09:05	8.45	24%	84.1°
2042-03-26 Wed	47	—	unknown	02:45–04:40 (good, 1.92 h)	87.2° 09:00	8.4	34%	90.8°
2042-03-27 Thu	48	—	unknown	02:45–04:40 (good, 1.92 h)	87.2° 09:00	8.35	44%	97.1°
2042-03-28 Fri	48	—	unknown	02:50–04:35 (good, 1.75 h)	87.3° 08:55	8.29	55%	103.0°
2042-03-29 Sat	48	—	unknown	02:45–05:35 (good, 1.83 h)	87.3° 09:50	8.24	64%	108.2°
2042-03-30 Sun	48	—	unknown	03:40–05:35 (good, 1.92 h)	87.3° 09:45	8.18	74%	112.6°
2042-03-31 Mon	44	—	unknown	03:40–05:30 (good, 1.83 h)	87.2° 09:40	8.13	82%	115.9°
2042-04-01 Tue	43	—	unknown	03:35–05:30 (good, 1.92 h)	87.3° 09:40	8.08	88%	118.0°
2042-04-02 Wed	42	—	unknown	03:35–05:25 (good, 1.83 h)	87.3° 09:35	8.02	94%	118.9°
2042-04-03 Thu	43	—	unknown	03:30–05:25 (good, 1.92 h)	87.3° 09:30	7.97	98%	118.4°
2042-04-04 Fri	43	—	unknown	03:30–05:25 (good, 1.92 h)	87.3° 09:25	7.91	100%	116.6°
2042-04-05 Sat	40	—	unknown	03:25–05:20 (good, 1.92 h)	87.2° 09:25	7.85	100%	113.6°
2042-04-06 Sun	40	—	unknown	03:25–05:20 (good, 1.92 h)	87.3° 09:20	7.8	98%	109.6°
2042-04-07 Mon	38	—	unknown	03:25–05:15 (good, 1.83 h)	87.3° 09:15	7.74	95%	104.8°
2042-04-08 Tue	38	—	unknown	03:20–05:15 (good, 1.92 h)	87.3° 09:10	7.69	90%	99.4°
2042-04-09 Wed	39	—	unknown	03:15–05:15 (good, 2.0 h)	87.2° 09:05	7.63	83%	93.6°
2042-04-10 Thu	39	—	unknown	03:10–05:10 (good, 2.0 h)	87.2° 09:05	7.57	75%	87.6°
2042-04-11 Fri	41	—	unknown	03:05–05:10 (good, 2.08 h)	87.3° 09:00	7.52	66%	81.6°
2042-04-12 Sat	48	—	unknown	02:40–05:10 (good, 2.5 h)	87.3° 08:55	7.46	56%	75.7°
2042-04-13 Sun	54	—	unknown	02:35–05:05 (good, 2.5 h)	87.3° 08:50	7.4	45%	70.4°
2042-04-14 Mon	60	—	unknown	02:30–05:05 (good, 2.58 h)	87.2° 08:45	7.34	34%	65.9°
2042-04-15 Tue	64	—	unknown	02:30–05:00 (good, 2.5 h)	87.3° 08:45	7.29	24%	62.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-03-17&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.