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: 09-22 (100), 09-23 (100), 09-24 (100), 09-25 (100), 09-26 (100) — by astronomy; check the weather when the night is within four days.

2038-09-17astronomy score per night — click a bar for that night2038-10-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-09-17 Fri	59	—	unknown	21:40–21:45 (good, 0.08 h)	79.2° 03:10	8.48	83%	25.6°
2038-09-18 Sat	80	—	unknown	21:40–22:10 (good, 0.5 h)	79.2° 03:05	8.53	75%	31.7°
2038-09-19 Sun	85	—	unknown	21:35–02:30 (good, 4.92 h)	79.2° 03:00	8.59	67%	40.2°
2038-09-20 Mon	90	—	unknown	21:30–05:35 (good, 8.08 h)	79.2° 02:55	8.64	57%	50.0°
2038-09-21 Tue	95	—	unknown	21:25–05:35 (good, 8.17 h)	79.2° 02:55	8.69	48%	60.6°
2038-09-22 Wed	100	—	unknown	21:20–05:40 (good, 8.33 h)	79.2° 02:50	8.74	38%	71.8°
2038-09-23 Thu	100	—	unknown	21:20–05:40 (good, 8.33 h)	79.2° 02:45	8.79	28%	83.5°
2038-09-24 Fri	100	—	unknown	21:15–05:40 (good, 8.42 h)	79.2° 02:40	8.84	19%	95.7°
2038-09-25 Sat	100	—	unknown	21:10–05:40 (good, 8.5 h)	79.2° 02:40	8.89	11%	108.2°
2038-09-26 Sun	100	—	unknown	21:05–05:45 (good, 8.67 h)	79.2° 02:35	8.94	5%	120.9°
2038-09-27 Mon	100	—	unknown	21:00–05:45 (good, 8.75 h)	79.2° 02:30	8.99	1%	133.4°
2038-09-28 Tue	100	—	unknown	21:00–05:45 (good, 8.75 h)	79.2° 02:25	9.04	0%	145.0°
2038-09-29 Wed	100	—	unknown	20:55–05:45 (good, 8.83 h)	79.2° 02:20	9.09	2%	153.8°
2038-09-30 Thu	100	—	unknown	20:50–05:50 (good, 9.0 h)	79.2° 02:20	9.14	7%	155.9°
2038-10-01 Fri	100	—	unknown	20:50–05:50 (good, 9.0 h)	79.2° 02:15	9.18	14%	150.1°
2038-10-02 Sat	100	—	unknown	20:45–05:50 (good, 9.08 h)	79.2° 02:10	9.23	23%	139.9°
2038-10-03 Sun	100	—	unknown	20:40–05:50 (good, 9.17 h)	79.2° 02:05	9.28	34%	128.1°
2038-10-04 Mon	100	—	unknown	20:40–05:50 (good, 9.17 h)	79.2° 02:00	9.33	45%	115.9°
2038-10-05 Tue	100	—	unknown	20:40–05:55 (good, 9.25 h)	79.2° 02:00	9.37	56%	103.7°
2038-10-06 Wed	100	—	unknown	20:45–05:55 (good, 9.17 h)	79.2° 01:55	9.42	66%	91.6°
2038-10-07 Thu	100	—	unknown	20:50–05:55 (good, 9.08 h)	79.2° 01:50	9.47	75%	79.9°
2038-10-08 Fri	100	—	unknown	22:10–05:55 (good, 7.75 h)	79.2° 01:45	9.51	83%	68.4°
2038-10-09 Sat	97	—	unknown	01:15–06:00 (good, 4.75 h)	79.2° 01:40	9.56	90%	57.3°
2038-10-10 Sun	89	—	unknown	04:25–06:00 (good, 1.58 h)	79.2° 01:40	9.6	95%	46.8°
2038-10-11 Mon	51	—	unknown	20:20–06:00 (marginal, 9.67 h)	79.2° 01:35	9.65	98%	37.1°
2038-10-12 Tue	37	—	unknown	01:50–06:00 (marginal, 4.17 h)	79.2° 01:30	9.69	100%	29.2°
2038-10-13 Wed	36	—	unknown	20:20–00:20 (marginal, 4.0 h)	79.2° 01:25	9.74	99%	24.3°
2038-10-14 Thu	40	—	unknown	20:15–01:00 (marginal, 4.75 h)	79.2° 01:25	9.78	97%	24.5°
2038-10-15 Fri	48	—	unknown	19:50–02:20 (marginal, 6.5 h)	79.2° 01:20	9.82	93%	29.5°
2038-10-16 Sat	83	—	unknown	20:15–20:45 (good, 0.5 h)	79.2° 01:15	9.87	88%	37.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-09-17&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.