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: 05-30 (100), 05-31 (100), 06-01 (100), 06-02 (100), 06-03 (100) — by astronomy; check the weather when the night is within four days.

2046-05-09astronomy score per night — click a bar for that night2046-06-07

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-05-09 Wed	90	—	unknown	00:55–04:15 (good, 3.33 h)	87.2° 07:10	5.9	15%	101.1°
2046-05-10 Thu	91	—	unknown	00:55–04:15 (good, 3.33 h)	87.2° 07:05	5.84	24%	108.3°
2046-05-11 Fri	92	—	unknown	00:50–04:15 (good, 3.42 h)	87.2° 07:00	5.79	33%	114.8°
2046-05-12 Sat	92	—	unknown	00:45–04:10 (good, 3.42 h)	87.2° 06:55	5.73	44%	120.2°
2046-05-13 Sun	93	—	unknown	00:45–04:10 (good, 3.42 h)	87.2° 06:55	5.68	56%	123.9°
2046-05-14 Mon	93	—	unknown	00:40–04:10 (good, 3.5 h)	87.2° 06:50	5.62	67%	125.4°
2046-05-15 Tue	91	—	unknown	00:40–04:05 (good, 3.42 h)	87.2° 06:45	5.57	77%	124.4°
2046-05-16 Wed	92	—	unknown	00:40–04:05 (good, 3.42 h)	87.2° 06:40	5.52	86%	120.9°
2046-05-17 Thu	82	—	unknown	00:40–04:05 (good, 3.42 h)	87.1° 06:35	5.46	93%	115.5°
2046-05-18 Fri	74	—	unknown	00:40–04:00 (good, 3.33 h)	87.2° 06:35	5.41	98%	108.7°
2046-05-19 Sat	67	—	unknown	00:40–04:00 (good, 3.33 h)	87.2° 06:30	5.36	100%	101.0°
2046-05-20 Sun	62	—	unknown	00:40–04:00 (good, 3.33 h)	87.2° 06:25	5.31	99%	93.0°
2046-05-21 Mon	58	—	unknown	00:40–04:00 (good, 3.33 h)	87.2° 06:20	5.26	96%	85.1°
2046-05-22 Tue	56	—	unknown	00:35–03:55 (good, 3.33 h)	87.2° 06:20	5.21	91%	77.5°
2046-05-23 Wed	58	—	unknown	00:25–03:55 (good, 3.5 h)	87.2° 06:15	5.17	84%	70.7°
2046-05-24 Thu	71	—	unknown	23:55–03:55 (good, 4.0 h)	87.2° 06:10	5.12	76%	64.7°
2046-05-25 Fri	78	—	unknown	23:50–03:55 (good, 4.08 h)	87.2° 06:05	5.07	67%	59.9°
2046-05-26 Sat	86	—	unknown	23:45–03:50 (good, 4.08 h)	87.2° 06:00	5.03	57%	56.5°
2046-05-27 Sun	92	—	unknown	23:45–03:50 (good, 4.08 h)	87.2° 06:00	4.99	48%	54.7°
2046-05-28 Mon	94	—	unknown	23:40–03:50 (good, 4.17 h)	87.2° 05:55	4.94	39%	54.7°
2046-05-29 Tue	97	—	unknown	23:35–03:50 (good, 4.25 h)	87.2° 05:50	4.9	30%	56.3°
2046-05-30 Wed	100	—	unknown	23:30–03:45 (good, 4.25 h)	87.2° 05:45	4.86	21%	59.6°
2046-05-31 Thu	100	—	unknown	23:25–03:45 (good, 4.33 h)	87.1° 05:40	4.83	14%	64.2°
2046-06-01 Fri	100	—	unknown	23:25–03:45 (good, 4.33 h)	87.2° 05:40	4.79	8%	69.9°
2046-06-02 Sat	100	—	unknown	23:20–03:45 (good, 4.42 h)	87.2° 05:35	4.75	3%	76.5°
2046-06-03 Sun	100	—	unknown	23:15–03:45 (good, 4.5 h)	87.2° 05:30	4.72	1%	83.8°
2046-06-04 Mon	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.2° 05:25	4.69	0%	91.4°
2046-06-05 Tue	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 05:25	4.66	2%	99.1°
2046-06-06 Wed	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.2° 05:20	4.63	6%	106.6°
2046-06-07 Thu	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.2° 05:15	4.6	12%	113.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-05-09&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.