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: 12-17 (100), 12-18 (100), 12-19 (100), 12-20 (100), 12-21 (100) — by astronomy; check the weather when the night is within four days.

2038-12-17astronomy score per night — click a bar for that night2039-01-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-12-17 Fri	100	—	unknown	18:35–01:35 (good, 7.0 h)	79.2° 20:10	11.5	66%	120.3°
2038-12-18 Sat	100	—	unknown	18:35–01:35 (good, 7.0 h)	79.2° 20:05	11.5	55%	131.9°
2038-12-19 Sun	100	—	unknown	18:35–01:30 (good, 6.92 h)	79.2° 20:05	11.51	44%	142.8°
2038-12-20 Mon	100	—	unknown	18:35–01:30 (good, 6.92 h)	79.2° 20:00	11.51	33%	151.9°
2038-12-21 Tue	100	—	unknown	18:35–01:30 (good, 6.92 h)	79.2° 19:55	11.51	23%	156.2°
2038-12-22 Wed	100	—	unknown	18:35–01:25 (good, 6.83 h)	79.2° 19:50	11.51	14%	152.7°
2038-12-23 Thu	100	—	unknown	18:40–01:20 (good, 6.67 h)	79.2° 19:50	11.51	6%	143.5°
2038-12-24 Fri	100	—	unknown	18:40–01:15 (good, 6.58 h)	79.2° 19:45	11.5	2%	131.6°
2038-12-25 Sat	100	—	unknown	18:40–01:10 (good, 6.5 h)	79.2° 19:40	11.5	0%	118.7°
2038-12-26 Sun	100	—	unknown	18:40–01:10 (good, 6.5 h)	79.2° 19:35	11.5	1%	105.5°
2038-12-27 Mon	100	—	unknown	18:40–01:05 (good, 6.42 h)	79.2° 19:30	11.49	5%	92.5°
2038-12-28 Tue	100	—	unknown	18:40–01:00 (good, 6.33 h)	79.2° 19:30	11.48	11%	79.7°
2038-12-29 Wed	100	—	unknown	18:40–00:55 (good, 6.25 h)	79.2° 19:25	11.48	18%	67.5°
2038-12-30 Thu	98	—	unknown	18:40–00:50 (good, 6.17 h)	79.2° 19:20	11.47	27%	56.0°
2038-12-31 Fri	90	—	unknown	18:45–00:50 (good, 6.08 h)	79.2° 19:15	11.46	37%	45.2°
2039-01-01 Sat	82	—	unknown	18:45–00:45 (good, 6.0 h)	79.2° 19:10	11.45	46%	35.6°
2039-01-02 Sun	65	—	unknown	18:45–00:00 (good, 5.25 h)	79.2° 19:10	11.44	56%	28.0°
2039-01-03 Mon	48	—	unknown	18:45–01:00 (marginal, 6.25 h)	79.2° 19:05	11.43	65%	24.0°
2039-01-04 Tue	34	—	unknown	18:45–00:45 (marginal, 6.0 h)	79.2° 19:00	11.42	74%	25.2°
2039-01-05 Wed	26	—	unknown	18:45–00:25 (marginal, 5.67 h)	79.2° 18:55	11.4	82%	30.9°
2039-01-06 Thu	25	—	unknown	18:50–00:10 (marginal, 5.33 h)	79.2° 18:55	11.39	88%	39.3°
2039-01-07 Fri	29	—	unknown	18:50–00:05 (marginal, 5.25 h)	79.2° 18:50	11.38	94%	49.0°
2039-01-08 Sat	37	—	unknown	18:50–00:05 (marginal, 5.25 h)	79.2° 18:45	11.36	98%	59.6°
2039-01-09 Sun	49	—	unknown	18:50–19:45 (good, 0.92 h)	79.2° 18:40	11.34	100%	70.7°
2039-01-10 Mon	65	—	unknown	18:50–21:40 (good, 2.83 h)	79.2° 18:35	11.33	100%	82.2°
2039-01-11 Tue	81	—	unknown	18:50–22:55 (good, 4.08 h)	79.2° 18:35	11.31	98%	93.9°
2039-01-12 Wed	100	—	unknown	18:55–23:40 (good, 4.75 h)	79.2° 18:30	11.29	94%	105.8°
2039-01-13 Thu	100	—	unknown	18:55–23:45 (good, 4.83 h)	79.2° 18:25	11.27	88%	117.7°
2039-01-14 Fri	100	—	unknown	18:55–23:45 (good, 4.83 h)	79.2° 18:20	11.25	80%	129.4°
2039-01-15 Sat	100	—	unknown	18:55–23:45 (good, 4.83 h)	79.2° 18:15	11.23	70%	140.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-12-17&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.