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 Triangulum Pinwheel: 12-15 (100), 12-16 (100), 12-17 (100), 12-18 (100), 12-19 (100) — by astronomy; check the weather when the night is within four days.

2039-12-15astronomy score per night — click a bar for that night2040-01-13

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-12-15 Thu	100	—	unknown	18:35–01:50 (good, 7.25 h)	79.2° 20:20	11.49	0%	124.2°
2039-12-16 Fri	100	—	unknown	18:35–01:50 (good, 7.25 h)	79.2° 20:15	11.5	2%	110.5°
2039-12-17 Sat	100	—	unknown	18:35–01:45 (good, 7.17 h)	79.2° 20:10	11.5	8%	96.7°
2039-12-18 Sun	100	—	unknown	18:35–01:40 (good, 7.08 h)	79.2° 20:10	11.5	15%	83.1°
2039-12-19 Mon	100	—	unknown	18:35–01:35 (good, 7.0 h)	79.2° 20:05	11.51	24%	69.9°
2039-12-20 Tue	99	—	unknown	18:35–01:35 (good, 7.0 h)	79.2° 20:00	11.51	34%	57.4°
2039-12-21 Wed	90	—	unknown	18:35–01:30 (good, 6.92 h)	79.2° 19:55	11.51	45%	45.8°
2039-12-22 Thu	82	—	unknown	18:35–01:25 (good, 6.83 h)	79.2° 19:55	11.51	55%	35.4°
2039-12-23 Fri	58	—	unknown	18:40–01:50 (marginal, 7.17 h)	79.2° 19:50	11.51	65%	27.1°
2039-12-24 Sat	41	—	unknown	18:40–01:35 (marginal, 6.92 h)	79.2° 19:45	11.5	74%	22.9°
2039-12-25 Sun	30	—	unknown	18:40–01:15 (marginal, 6.58 h)	79.2° 19:40	11.5	82%	24.4°
2039-12-26 Mon	24	—	unknown	18:40–00:50 (marginal, 6.17 h)	79.2° 19:35	11.5	89%	30.7°
2039-12-27 Tue	26	—	unknown	18:40–23:55 (marginal, 5.25 h)	79.2° 19:35	11.49	94%	39.5°
2039-12-28 Wed	34	—	unknown	18:40–00:35 (marginal, 5.92 h)	79.2° 19:30	11.49	98%	49.3°
2039-12-29 Thu	45	—	unknown	18:40–00:45 (marginal, 6.08 h)	79.2° 19:25	11.48	100%	59.7°
2039-12-30 Fri	61	—	unknown	18:40–20:20 (good, 1.67 h)	79.2° 19:20	11.47	100%	70.5°
2039-12-31 Sat	75	—	unknown	18:45–22:20 (good, 3.58 h)	79.2° 19:15	11.46	98%	81.4°
2040-01-01 Sun	100	—	unknown	18:45–23:35 (good, 4.83 h)	79.2° 19:15	11.45	95%	92.4°
2040-01-02 Mon	100	—	unknown	18:45–00:20 (good, 5.58 h)	79.2° 19:10	11.44	90%	103.6°
2040-01-03 Tue	100	—	unknown	18:45–00:25 (good, 5.67 h)	79.2° 19:05	11.43	83%	114.7°
2040-01-04 Wed	100	—	unknown	18:45–00:25 (good, 5.67 h)	79.2° 19:00	11.42	75%	125.8°
2040-01-05 Thu	100	—	unknown	18:45–00:25 (good, 5.67 h)	79.2° 18:55	11.41	66%	136.6°
2040-01-06 Fri	100	—	unknown	18:45–00:20 (good, 5.58 h)	79.2° 18:55	11.39	56%	146.7°
2040-01-07 Sat	100	—	unknown	18:50–00:20 (good, 5.5 h)	79.2° 18:50	11.38	45%	154.6°
2040-01-08 Sun	100	—	unknown	18:50–00:20 (good, 5.5 h)	79.2° 18:45	11.36	34%	157.3°
2040-01-09 Mon	100	—	unknown	18:50–00:15 (good, 5.42 h)	79.2° 18:40	11.35	24%	152.6°
2040-01-10 Tue	100	—	unknown	18:50–00:10 (good, 5.33 h)	79.2° 18:40	11.33	15%	142.7°
2040-01-11 Wed	100	—	unknown	18:50–00:05 (good, 5.25 h)	79.2° 18:35	11.31	7%	130.4°
2040-01-12 Thu	100	—	unknown	18:55–00:00 (good, 5.08 h)	79.2° 18:30	11.29	2%	117.0°
2040-01-13 Fri	100	—	unknown	18:55–00:00 (good, 5.08 h)	79.2° 18:25	11.27	0%	103.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-12-15&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.