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 North America Nebula: 07-13 (100), 07-14 (100), 07-15 (100), 07-16 (100), 07-25 (100) — by astronomy; check the weather when the night is within four days.

2035-07-13astronomy score per night — click a bar for that night2035-08-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-07-13 Fri	100	—	unknown	23:00–03:55 (good, 4.92 h)	87.2° 02:55	4.91	66%	101.3°
2035-07-14 Sat	100	—	unknown	23:00–04:00 (good, 5.0 h)	87.2° 02:50	4.95	75%	95.0°
2035-07-15 Sun	100	—	unknown	23:00–04:00 (good, 5.0 h)	87.2° 02:45	4.99	82%	88.6°
2035-07-16 Mon	100	—	unknown	23:00–04:00 (good, 5.0 h)	87.2° 02:45	5.03	89%	82.3°
2035-07-17 Tue	76	—	unknown	23:00–04:00 (good, 5.0 h)	87.2° 02:40	5.08	94%	76.2°
2035-07-18 Wed	71	—	unknown	23:00–04:05 (good, 5.08 h)	87.2° 02:35	5.12	98%	70.6°
2035-07-19 Thu	60	—	unknown	02:05–04:05 (good, 2.0 h)	87.2° 02:30	5.17	100%	65.6°
2035-07-20 Fri	54	—	unknown	22:55–04:05 (marginal, 5.17 h)	87.2° 02:25	5.22	100%	61.6°
2035-07-21 Sat	55	—	unknown	22:50–23:55 (good, 1.08 h)	87.2° 02:25	5.26	98%	58.8°
2035-07-22 Sun	59	—	unknown	22:50–00:35 (good, 1.75 h)	87.2° 02:20	5.31	94%	57.5°
2035-07-23 Mon	68	—	unknown	22:50–01:45 (good, 2.92 h)	87.2° 02:15	5.36	89%	57.9°
2035-07-24 Tue	97	—	unknown	22:50–04:05 (good, 5.25 h)	87.2° 02:10	5.41	82%	60.0°
2035-07-25 Wed	100	—	unknown	22:45–04:15 (good, 5.5 h)	87.2° 02:05	5.46	73%	63.7°
2035-07-26 Thu	100	—	unknown	22:45–04:15 (good, 5.5 h)	87.2° 02:05	5.52	63%	68.8°
2035-07-27 Fri	100	—	unknown	22:45–04:15 (good, 5.5 h)	87.2° 02:00	5.57	52%	75.0°
2035-07-28 Sat	100	—	unknown	22:40–04:20 (good, 5.67 h)	87.2° 01:55	5.62	41%	82.0°
2035-07-29 Sun	100	—	unknown	22:40–04:20 (good, 5.67 h)	87.2° 01:50	5.67	30%	89.6°
2035-07-30 Mon	100	—	unknown	22:40–04:20 (good, 5.67 h)	87.2° 01:45	5.73	20%	97.3°
2035-07-31 Tue	100	—	unknown	22:35–04:25 (good, 5.83 h)	87.2° 01:45	5.78	11%	104.8°
2035-08-01 Wed	100	—	unknown	22:35–04:25 (good, 5.83 h)	87.2° 01:40	5.84	5%	111.6°
2035-08-02 Thu	100	—	unknown	22:35–04:25 (good, 5.83 h)	87.2° 01:35	5.89	1%	117.2°
2035-08-03 Fri	100	—	unknown	22:30–04:30 (good, 6.0 h)	87.2° 01:30	5.95	0%	121.0°
2035-08-04 Sat	100	—	unknown	22:30–04:30 (good, 6.0 h)	87.2° 01:30	6.0	2%	122.5°
2035-08-05 Sun	100	—	unknown	22:30–04:30 (good, 6.0 h)	87.2° 01:25	6.06	7%	121.7°
2035-08-06 Mon	100	—	unknown	22:25–04:35 (good, 6.17 h)	87.2° 01:20	6.12	13%	118.9°
2035-08-07 Tue	100	—	unknown	22:25–04:35 (good, 6.17 h)	87.2° 01:15	6.17	22%	114.5°
2035-08-08 Wed	100	—	unknown	22:20–04:35 (good, 6.25 h)	87.2° 01:10	6.23	31%	109.2°
2035-08-09 Thu	100	—	unknown	22:20–04:40 (good, 6.33 h)	87.2° 01:10	6.29	40%	103.1°
2035-08-10 Fri	100	—	unknown	22:20–04:40 (good, 6.33 h)	87.2° 01:05	6.34	50%	96.8°
2035-08-11 Sat	100	—	unknown	22:15–04:40 (good, 6.42 h)	87.2° 01:00	6.4	60%	90.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-07-13&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.