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: 05-17 (100), 05-18 (100), 05-19 (100), 05-20 (100), 05-21 (100) — by astronomy; check the weather when the night is within four days.

2029-05-12astronomy score per night — click a bar for that night2029-06-10

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2029-05-12 Sat	94	—	unknown	00:40–04:10 (good, 3.5 h)	87.2° 06:55	5.72	0%	73.9°
2029-05-13 Sun	96	—	unknown	00:35–04:10 (good, 3.58 h)	87.2° 06:50	5.67	0%	80.9°
2029-05-14 Mon	97	—	unknown	00:35–04:10 (good, 3.58 h)	87.2° 06:50	5.62	2%	88.2°
2029-05-15 Tue	97	—	unknown	00:30–04:05 (good, 3.58 h)	87.2° 06:45	5.56	5%	95.7°
2029-05-16 Wed	99	—	unknown	00:25–04:05 (good, 3.67 h)	87.2° 06:40	5.51	11%	103.1°
2029-05-17 Thu	100	—	unknown	00:20–04:05 (good, 3.75 h)	87.2° 06:35	5.46	18%	110.2°
2029-05-18 Fri	100	—	unknown	00:20–04:00 (good, 3.67 h)	87.2° 06:30	5.41	26%	116.6°
2029-05-19 Sat	100	—	unknown	00:15–04:00 (good, 3.75 h)	87.2° 06:30	5.36	36%	122.0°
2029-05-20 Sun	100	—	unknown	00:15–04:00 (good, 3.75 h)	87.2° 06:25	5.31	47%	125.7°
2029-05-21 Mon	100	—	unknown	00:15–04:00 (good, 3.75 h)	87.2° 06:20	5.26	58%	127.2°
2029-05-22 Tue	100	—	unknown	00:10–03:55 (good, 3.75 h)	87.2° 06:15	5.21	70%	126.2°
2029-05-23 Wed	100	—	unknown	00:10–03:55 (good, 3.75 h)	87.2° 06:15	5.16	80%	122.6°
2029-05-24 Thu	99	—	unknown	00:10–03:55 (good, 3.75 h)	87.2° 06:10	5.11	88%	116.8°
2029-05-25 Fri	83	—	unknown	00:10–03:55 (good, 3.75 h)	87.2° 06:05	5.07	95%	109.4°
2029-05-26 Sat	74	—	unknown	00:10–03:50 (good, 3.67 h)	87.2° 06:00	5.03	99%	101.0°
2029-05-27 Sun	66	—	unknown	00:15–03:50 (good, 3.58 h)	87.2° 05:55	4.98	100%	92.2°
2029-05-28 Mon	59	—	unknown	00:35–03:50 (good, 3.25 h)	87.2° 05:55	4.94	98%	83.4°
2029-05-29 Tue	55	—	unknown	00:40–03:50 (good, 3.17 h)	87.2° 05:50	4.9	94%	75.1°
2029-05-30 Wed	56	—	unknown	00:05–03:45 (good, 3.67 h)	87.2° 05:45	4.86	88%	67.7°
2029-05-31 Thu	72	—	unknown	23:25–03:45 (good, 4.33 h)	87.2° 05:40	4.82	80%	61.4°
2029-06-01 Fri	80	—	unknown	23:20–03:45 (good, 4.42 h)	87.2° 05:35	4.79	70%	56.7°
2029-06-02 Sat	87	—	unknown	23:20–03:45 (good, 4.42 h)	87.2° 05:35	4.75	61%	53.7°
2029-06-03 Sun	91	—	unknown	23:15–03:45 (good, 4.5 h)	87.2° 05:30	4.72	51%	52.7°
2029-06-04 Mon	94	—	unknown	23:10–03:45 (good, 4.58 h)	87.2° 05:25	4.68	42%	53.6°
2029-06-05 Tue	97	—	unknown	23:05–03:40 (good, 4.58 h)	87.2° 05:20	4.65	32%	56.3°
2029-06-06 Wed	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.2° 05:20	4.63	24%	60.4°
2029-06-07 Thu	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.2° 05:15	4.6	16%	65.8°
2029-06-08 Fri	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.2° 05:10	4.57	10%	72.0°
2029-06-09 Sat	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.2° 05:05	4.55	5%	78.8°
2029-06-10 Sun	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.2° 05:00	4.53	2%	86.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-05-12&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.