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: 09-03 (100), 09-04 (100), 09-05 (100), 09-06 (100), 09-07 (100) — by astronomy; check the weather when the night is within four days.

2038-09-03astronomy score per night — click a bar for that night2038-10-02

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-09-03 Fri	100	—	unknown	22:35–05:15 (good, 6.67 h)	79.2° 04:05	7.73	26%	154.5°
2038-09-04 Sat	100	—	unknown	22:35–05:15 (good, 6.67 h)	79.2° 04:00	7.78	37%	147.1°
2038-09-05 Sun	100	—	unknown	22:35–05:15 (good, 6.67 h)	79.2° 03:55	7.84	48%	136.6°
2038-09-06 Mon	100	—	unknown	22:30–05:20 (good, 6.83 h)	79.2° 03:50	7.89	60%	124.9°
2038-09-07 Tue	100	—	unknown	22:30–05:20 (good, 6.83 h)	79.2° 03:50	7.95	70%	112.9°
2038-09-08 Wed	100	—	unknown	22:35–05:20 (good, 6.75 h)	79.2° 03:45	8.0	79%	100.8°
2038-09-09 Thu	100	—	unknown	22:40–05:25 (good, 6.75 h)	79.2° 03:40	8.06	87%	88.8°
2038-09-10 Fri	100	—	unknown	23:45–05:25 (good, 5.67 h)	79.2° 03:35	8.11	93%	77.0°
2038-09-11 Sat	73	—	unknown	01:35–05:25 (good, 3.83 h)	79.2° 03:35	8.16	97%	65.5°
2038-09-12 Sun	63	—	unknown	04:50–05:25 (good, 0.58 h)	79.2° 03:30	8.22	100%	54.4°
2038-09-13 Mon	47	—	unknown	21:50–05:30 (marginal, 7.67 h)	79.2° 03:25	8.27	100%	44.0°
2038-09-14 Tue	34	—	unknown	21:50–05:30 (marginal, 7.67 h)	79.2° 03:20	8.32	98%	34.7°
2038-09-15 Wed	32	—	unknown	21:40–05:30 (marginal, 7.83 h)	79.2° 03:15	8.38	94%	27.4°
2038-09-16 Thu	39	—	unknown	21:30–05:30 (marginal, 8.0 h)	79.2° 03:15	8.43	89%	23.9°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-09-03&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.