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: 09-29 (100), 09-30 (100), 10-01 (100), 10-02 (100), 10-03 (100) — by astronomy; check the weather when the night is within four days.

2027-09-29astronomy score per night — click a bar for that night2027-10-28

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-09-29 Wed	100	—	unknown	20:40–04:10 (good, 7.5 h)	87.2° 21:50	9.07	0%	123.2°
2027-09-30 Thu	100	—	unknown	20:40–04:05 (good, 7.42 h)	87.2° 21:45	9.12	1%	119.1°
2027-10-01 Fri	100	—	unknown	20:40–04:00 (good, 7.33 h)	87.3° 21:40	9.17	4%	113.3°
2027-10-02 Sat	100	—	unknown	20:35–03:55 (good, 7.33 h)	87.3° 21:35	9.22	10%	106.5°
2027-10-03 Sun	100	—	unknown	20:35–03:50 (good, 7.25 h)	87.2° 21:30	9.26	17%	99.3°
2027-10-04 Mon	100	—	unknown	20:35–03:50 (good, 7.25 h)	87.2° 21:30	9.31	26%	92.0°
2027-10-05 Tue	100	—	unknown	20:30–03:45 (good, 7.25 h)	87.2° 21:25	9.36	35%	84.8°
2027-10-06 Wed	100	—	unknown	20:30–03:40 (good, 7.17 h)	87.3° 21:20	9.4	44%	77.9°
2027-10-07 Thu	100	—	unknown	20:30–03:35 (good, 7.08 h)	87.2° 21:15	9.45	54%	71.5°
2027-10-08 Fri	92	—	unknown	20:25–03:30 (good, 7.08 h)	87.2° 21:10	9.5	63%	65.8°
2027-10-09 Sat	85	—	unknown	20:25–03:30 (good, 7.08 h)	87.2° 21:10	9.54	72%	61.0°
2027-10-10 Sun	67	—	unknown	20:25–02:30 (good, 6.08 h)	87.3° 21:05	9.59	80%	57.4°
2027-10-11 Mon	58	—	unknown	20:20–03:50 (marginal, 7.5 h)	87.3° 21:00	9.63	87%	55.2°
2027-10-12 Tue	53	—	unknown	20:20–03:40 (marginal, 7.33 h)	87.2° 20:55	9.68	93%	54.8°
2027-10-13 Wed	49	—	unknown	20:20–03:20 (marginal, 7.0 h)	87.2° 20:55	9.72	97%	56.1°
2027-10-14 Thu	51	—	unknown	20:15–03:10 (marginal, 6.92 h)	87.2° 20:50	9.77	99%	59.3°
2027-10-15 Fri	57	—	unknown	20:15–20:45 (good, 0.5 h)	87.3° 20:45	9.81	100%	64.1°
2027-10-16 Sat	68	—	unknown	20:15–22:10 (good, 1.92 h)	87.3° 20:40	9.85	98%	70.1°
2027-10-17 Sun	75	—	unknown	20:10–23:55 (good, 3.75 h)	87.2° 20:35	9.9	94%	77.1°
2027-10-18 Mon	82	—	unknown	20:10–01:00 (good, 4.83 h)	87.2° 20:35	9.94	88%	84.6°
2027-10-19 Tue	100	—	unknown	20:10–02:10 (good, 6.0 h)	87.2° 20:30	9.98	80%	92.5°
2027-10-20 Wed	100	—	unknown	20:10–02:25 (good, 6.25 h)	87.3° 20:25	10.02	70%	100.4°
2027-10-21 Thu	100	—	unknown	20:05–02:30 (good, 6.42 h)	87.2° 20:20	10.07	59%	107.9°
2027-10-22 Fri	100	—	unknown	20:05–02:30 (good, 6.42 h)	87.2° 20:15	10.11	48%	114.7°
2027-10-23 Sat	100	—	unknown	20:05–02:30 (good, 6.42 h)	87.2° 20:15	10.15	36%	120.2°
2027-10-24 Sun	100	—	unknown	20:00–02:30 (good, 6.5 h)	87.3° 20:10	10.19	26%	123.9°
2027-10-25 Mon	100	—	unknown	20:00–02:25 (good, 6.42 h)	87.3° 20:05	10.23	16%	125.4°
2027-10-26 Tue	100	—	unknown	20:00–02:20 (good, 6.33 h)	87.2° 20:00	10.27	9%	124.3°
2027-10-27 Wed	100	—	unknown	20:00–02:20 (good, 6.33 h)	87.2° 20:00	10.31	4%	120.9°
2027-10-28 Thu	100	—	unknown	19:55–02:15 (good, 6.33 h)	87.2° 19:55	10.34	1%	115.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-09-29&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.