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: 05-31 (100), 06-01 (100), 06-02 (100), 06-03 (100), 06-04 (100) — by astronomy; check the weather when the night is within four days.

2035-05-15astronomy score per night — click a bar for that night2035-06-13

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-05-15 Tue	92	—	unknown	00:40–04:05 (good, 3.42 h)	87.2° 06:45	5.59	66%	122.3°
2035-05-16 Wed	92	—	unknown	00:40–04:05 (good, 3.42 h)	87.2° 06:40	5.53	75%	119.7°
2035-05-17 Thu	83	—	unknown	00:40–04:05 (good, 3.42 h)	87.2° 06:40	5.48	83%	115.7°
2035-05-18 Fri	78	—	unknown	00:40–04:05 (good, 3.42 h)	87.2° 06:35	5.43	90%	110.6°
2035-05-19 Sat	70	—	unknown	00:40–04:00 (good, 3.33 h)	87.2° 06:30	5.38	95%	104.8°
2035-05-20 Sun	64	—	unknown	00:45–04:00 (good, 3.25 h)	87.2° 06:25	5.33	98%	98.5°
2035-05-21 Mon	58	—	unknown	01:10–04:00 (good, 2.83 h)	87.2° 06:25	5.28	100%	92.0°
2035-05-22 Tue	53	—	unknown	01:35–03:55 (good, 2.33 h)	87.2° 06:20	5.23	99%	85.6°
2035-05-23 Wed	50	—	unknown	01:50–03:55 (good, 2.08 h)	87.2° 06:15	5.18	97%	79.3°
2035-05-24 Thu	48	—	unknown	01:50–03:55 (good, 2.08 h)	87.2° 06:10	5.14	93%	73.3°
2035-05-25 Fri	50	—	unknown	01:15–03:55 (good, 2.67 h)	87.2° 06:05	5.09	88%	67.9°
2035-05-26 Sat	58	—	unknown	00:20–03:50 (good, 3.5 h)	87.2° 06:05	5.05	81%	63.3°
2035-05-27 Sun	73	—	unknown	23:45–03:50 (good, 4.08 h)	87.2° 06:00	5.0	73%	59.8°
2035-05-28 Mon	83	—	unknown	23:40–03:50 (good, 4.17 h)	87.2° 05:55	4.96	64%	57.7°
2035-05-29 Tue	91	—	unknown	23:35–03:50 (good, 4.25 h)	87.2° 05:50	4.92	54%	57.1°
2035-05-30 Wed	96	—	unknown	23:30–03:45 (good, 4.25 h)	87.2° 05:45	4.88	44%	58.3°
2035-05-31 Thu	100	—	unknown	23:30–03:45 (good, 4.25 h)	87.2° 05:45	4.84	33%	61.4°
2035-06-01 Fri	100	—	unknown	23:25–03:45 (good, 4.33 h)	87.2° 05:40	4.8	24%	66.1°
2035-06-02 Sat	100	—	unknown	23:20–03:45 (good, 4.42 h)	87.2° 05:35	4.77	15%	72.3°
2035-06-03 Sun	100	—	unknown	23:15–03:45 (good, 4.5 h)	87.2° 05:30	4.73	7%	79.5°
2035-06-04 Mon	100	—	unknown	23:15–03:45 (good, 4.5 h)	87.2° 05:30	4.7	2%	87.4°
2035-06-05 Tue	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 05:25	4.67	0%	95.6°
2035-06-06 Wed	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.2° 05:20	4.64	1%	103.6°
2035-06-07 Thu	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.2° 05:15	4.61	5%	110.8°
2035-06-08 Fri	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.2° 05:10	4.59	12%	116.6°
2035-06-09 Sat	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.2° 05:10	4.56	20%	120.7°
2035-06-10 Sun	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.2° 05:05	4.54	30%	122.6°
2035-06-11 Mon	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 05:00	4.52	40%	122.4°
2035-06-12 Tue	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:55	4.5	51%	120.2°
2035-06-13 Wed	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:50	4.48	61%	116.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-05-15&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.