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: 07-15 (100), 07-16 (100), 07-17 (100), 07-18 (100), 07-19 (100) — by astronomy; check the weather when the night is within four days.

2028-07-15astronomy score per night — click a bar for that night2028-08-13

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-07-15 Sat	100	—	unknown	23:00–04:00 (good, 5.0 h)	87.2° 02:45	5.02	40%	68.2°
2028-07-16 Sun	100	—	unknown	23:00–04:00 (good, 5.0 h)	87.2° 02:40	5.06	30%	74.8°
2028-07-17 Mon	100	—	unknown	22:55–04:05 (good, 5.17 h)	87.2° 02:35	5.11	21%	82.2°
2028-07-18 Tue	100	—	unknown	22:55–04:05 (good, 5.17 h)	87.2° 02:30	5.15	13%	90.1°
2028-07-19 Wed	100	—	unknown	22:55–04:05 (good, 5.17 h)	87.2° 02:30	5.2	6%	98.2°
2028-07-20 Thu	100	—	unknown	22:55–04:10 (good, 5.25 h)	87.2° 02:25	5.25	2%	106.2°
2028-07-21 Fri	100	—	unknown	22:50–04:10 (good, 5.33 h)	87.3° 02:20	5.3	0%	113.7°
2028-07-22 Sat	100	—	unknown	22:50–04:10 (good, 5.33 h)	87.2° 02:15	5.35	1%	120.0°
2028-07-23 Sun	100	—	unknown	22:50–04:10 (good, 5.33 h)	87.2° 02:10	5.4	5%	124.5°
2028-07-24 Mon	100	—	unknown	22:45–04:15 (good, 5.5 h)	87.2° 02:10	5.45	11%	126.4°
2028-07-25 Tue	100	—	unknown	22:45–04:15 (good, 5.5 h)	87.2° 02:05	5.5	20%	125.6°
2028-07-26 Wed	100	—	unknown	22:45–04:15 (good, 5.5 h)	87.3° 02:00	5.55	30%	122.2°
2028-07-27 Thu	100	—	unknown	22:40–04:20 (good, 5.67 h)	87.2° 01:55	5.6	41%	116.9°
2028-07-28 Fri	100	—	unknown	22:40–04:20 (good, 5.67 h)	87.2° 01:50	5.66	52%	110.3°
2028-07-29 Sat	100	—	unknown	22:40–04:20 (good, 5.67 h)	87.2° 01:50	5.71	63%	102.9°
2028-07-30 Sun	100	—	unknown	22:35–04:25 (good, 5.83 h)	87.2° 01:45	5.77	73%	95.2°
2028-07-31 Mon	100	—	unknown	22:35–04:25 (good, 5.83 h)	87.2° 01:40	5.82	82%	87.5°
2028-08-01 Tue	100	—	unknown	22:35–04:25 (good, 5.83 h)	87.2° 01:35	5.88	89%	80.0°
2028-08-02 Wed	100	—	unknown	22:30–04:30 (good, 6.0 h)	87.2° 01:35	5.93	94%	73.0°
2028-08-03 Thu	70	—	unknown	22:30–04:30 (good, 6.0 h)	87.2° 01:30	5.99	98%	66.6°
2028-08-04 Fri	62	—	unknown	03:35–04:30 (good, 0.92 h)	87.3° 01:25	6.04	100%	61.2°
2028-08-05 Sat	58	—	unknown	22:25–04:35 (marginal, 6.17 h)	87.2° 01:20	6.1	100%	57.1°
2028-08-06 Sun	57	—	unknown	22:25–22:45 (good, 0.33 h)	87.2° 01:15	6.16	98%	54.5°
2028-08-07 Mon	61	—	unknown	22:25–23:15 (good, 0.83 h)	87.2° 01:15	6.21	94%	53.6°
2028-08-08 Tue	68	—	unknown	22:20–00:10 (good, 1.83 h)	87.2° 01:10	6.27	88%	54.5°
2028-08-09 Wed	74	—	unknown	22:20–01:35 (good, 3.25 h)	87.3° 01:05	6.33	82%	57.1°
2028-08-10 Thu	100	—	unknown	22:15–04:00 (good, 5.75 h)	87.2° 01:00	6.38	74%	61.1°
2028-08-11 Fri	100	—	unknown	22:15–04:40 (good, 6.42 h)	87.2° 00:55	6.44	65%	66.4°
2028-08-12 Sat	100	—	unknown	22:15–04:45 (good, 6.5 h)	87.2° 00:55	6.5	56%	72.6°
2028-08-13 Sun	100	—	unknown	22:10–04:45 (good, 6.58 h)	87.2° 00:50	6.56	46%	79.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-07-15&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.