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: 10-15 (100), 10-16 (100), 10-17 (100), 10-18 (100), 10-19 (100) — by astronomy; check the weather when the night is within four days.

2028-10-15astronomy score per night — click a bar for that night2028-11-13

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-10-15 Sun	100	—	unknown	20:15–03:00 (good, 6.75 h)	87.2° 20:40	9.84	7%	126.1°
2028-10-16 Mon	100	—	unknown	20:15–03:00 (good, 6.75 h)	87.2° 20:40	9.89	2%	123.1°
2028-10-17 Tue	100	—	unknown	20:10–02:55 (good, 6.75 h)	87.2° 20:35	9.93	0%	117.8°
2028-10-18 Wed	100	—	unknown	20:10–02:50 (good, 6.67 h)	87.2° 20:30	9.97	1%	110.8°
2028-10-19 Thu	100	—	unknown	20:10–02:45 (good, 6.58 h)	87.2° 20:25	10.01	5%	102.9°
2028-10-20 Fri	100	—	unknown	20:05–02:40 (good, 6.58 h)	87.2° 20:20	10.06	11%	94.5°
2028-10-21 Sat	100	—	unknown	20:05–02:40 (good, 6.58 h)	87.2° 20:20	10.1	19%	86.3°
2028-10-22 Sun	100	—	unknown	20:05–02:35 (good, 6.5 h)	87.2° 20:15	10.14	28%	78.4°
2028-10-23 Mon	100	—	unknown	20:05–02:30 (good, 6.42 h)	87.2° 20:10	10.18	37%	71.3°
2028-10-24 Tue	93	—	unknown	20:00–02:25 (good, 6.42 h)	87.2° 20:05	10.22	47%	65.0°
2028-10-25 Wed	85	—	unknown	20:00–02:20 (good, 6.33 h)	87.2° 20:00	10.26	57%	59.8°
2028-10-26 Thu	73	—	unknown	20:00–02:20 (good, 6.33 h)	87.2° 20:00	10.3	66%	56.1°
2028-10-27 Fri	62	—	unknown	20:00–23:40 (good, 3.67 h)	87.2° 19:55	10.33	75%	53.9°
2028-10-28 Sat	54	—	unknown	19:55–02:40 (marginal, 6.75 h)	87.2° 19:50	10.37	82%	53.4°
2028-10-29 Sun	47	—	unknown	18:55–01:25 (marginal, 6.5 h)	87.2° 18:45	10.41	89%	54.8°
2028-10-30 Mon	44	—	unknown	18:55–01:10 (marginal, 6.25 h)	87.2° 18:45	10.45	94%	57.9°
2028-10-31 Tue	46	—	unknown	18:55–01:00 (marginal, 6.08 h)	87.2° 18:40	10.48	98%	62.3°
2028-11-01 Wed	52	—	unknown	18:50–19:25 (good, 0.58 h)	87.2° 18:35	10.52	100%	68.0°
2028-11-02 Thu	62	—	unknown	18:50–20:55 (good, 2.08 h)	87.2° 18:30	10.56	100%	74.5°
2028-11-03 Fri	74	—	unknown	18:50–22:00 (good, 3.17 h)	87.2° 18:25	10.59	98%	81.6°
2028-11-04 Sat	81	—	unknown	18:50–23:05 (good, 4.25 h)	87.2° 18:25	10.63	94%	89.1°
2028-11-05 Sun	100	—	unknown	18:50–00:05 (good, 5.25 h)	87.2° 18:20	10.66	88%	96.7°
2028-11-06 Mon	100	—	unknown	18:45–00:15 (good, 5.5 h)	87.2° 18:15	10.69	80%	104.3°
2028-11-07 Tue	100	—	unknown	18:45–00:20 (good, 5.58 h)	87.2° 18:10	10.73	71%	111.4°
2028-11-08 Wed	100	—	unknown	18:45–00:20 (good, 5.58 h)	87.2° 18:05	10.76	61%	117.7°
2028-11-09 Thu	100	—	unknown	18:45–00:20 (good, 5.58 h)	87.2° 18:05	10.79	50%	122.8°
2028-11-10 Fri	100	—	unknown	18:45–00:20 (good, 5.58 h)	87.2° 18:00	10.82	38%	125.9°
2028-11-11 Sat	100	—	unknown	18:40–00:15 (good, 5.58 h)	87.2° 17:55	10.86	28%	126.7°
2028-11-12 Sun	100	—	unknown	18:40–00:10 (good, 5.5 h)	87.2° 17:50	10.89	18%	124.7°
2028-11-13 Mon	100	—	unknown	18:40–00:10 (good, 5.5 h)	87.2° 17:50	10.92	10%	120.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-10-15&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.