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: 02-12 (65), 02-11 (64), 02-13 (63), 02-14 (60), 02-10 (59) — by astronomy; check the weather when the night is within four days.

2039-02-09astronomy score per night — click a bar for that night2039-03-10

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-02-09 Wed	54	—	unknown	19:25–21:55 (good, 2.5 h)	79.2° 16:40	10.48	99%	114.2°
2039-02-10 Thu	59	—	unknown	19:25–21:55 (good, 2.5 h)	79.2° 16:35	10.45	96%	126.3°
2039-02-11 Fri	64	—	unknown	19:25–21:55 (good, 2.5 h)	79.2° 16:30	10.41	91%	137.9°
2039-02-12 Sat	65	—	unknown	19:25–21:55 (good, 2.5 h)	79.2° 16:25	10.37	83%	148.2°
2039-02-13 Sun	63	—	unknown	19:25–21:55 (good, 2.5 h)	79.2° 16:25	10.33	74%	155.2°
2039-02-14 Mon	60	—	unknown	19:30–21:50 (good, 2.33 h)	79.2° 16:20	10.29	63%	155.6°
2039-02-15 Tue	57	—	unknown	19:30–21:50 (good, 2.33 h)	79.2° 16:15	10.25	52%	149.2°
2039-02-16 Wed	56	—	unknown	19:30–21:45 (good, 2.25 h)	79.2° 16:10	10.21	41%	139.0°
2039-02-17 Thu	54	—	unknown	19:30–21:40 (good, 2.17 h)	79.2° 16:05	10.17	30%	127.3°
2039-02-18 Fri	51	—	unknown	19:35–21:35 (good, 2.0 h)	79.2° 16:05	10.13	20%	114.9°
2039-02-19 Sat	49	—	unknown	19:35–21:30 (good, 1.92 h)	79.2° 16:00	10.09	12%	102.3°
2039-02-20 Sun	47	—	unknown	19:35–21:30 (good, 1.92 h)	79.2° 15:55	10.05	6%	89.6°
2039-02-21 Mon	46	—	unknown	19:35–21:25 (good, 1.83 h)	79.2° 15:50	10.01	2%	77.2°
2039-02-22 Tue	43	—	unknown	19:40–21:20 (good, 1.67 h)	79.2° 15:50	9.96	0%	65.0°
2039-02-23 Wed	41	—	unknown	19:40–21:15 (good, 1.58 h)	79.2° 15:45	9.92	1%	53.4°
2039-02-24 Thu	39	—	unknown	19:40–21:10 (good, 1.5 h)	79.2° 15:40	9.88	4%	42.6°
2039-02-25 Fri	35	—	unknown	19:40–21:10 (good, 1.5 h)	79.2° 15:35	9.83	8%	33.1°
2039-02-26 Sat	31	—	unknown	19:40–21:00 (good, 1.33 h)	79.2° 15:30	9.79	14%	26.1°
2039-02-27 Sun	25	—	unknown	19:45–20:50 (good, 1.08 h)	79.2° 15:30	9.74	22%	23.5°
2039-02-28 Mon	21	—	unknown	19:45–20:40 (good, 0.92 h)	79.2° 15:25	9.7	30%	26.4°
2039-03-01 Tue	16	—	unknown	19:45–20:15 (good, 0.5 h)	79.2° 15:20	9.65	39%	33.2°
2039-03-02 Wed	13	—	unknown	19:45–21:15 (marginal, 1.5 h)	79.2° 15:15	9.61	48%	42.1°
2039-03-03 Thu	11	—	unknown	19:50–21:05 (marginal, 1.25 h)	79.2° 15:10	9.56	58%	52.1°
2039-03-04 Fri	10	—	unknown	19:50–21:00 (marginal, 1.17 h)	79.2° 15:10	9.52	67%	62.7°
2039-03-05 Sat	9	—	unknown	19:50–20:55 (marginal, 1.08 h)	79.2° 15:05	9.47	76%	73.8°
2039-03-06 Sun	10	—	unknown	19:50–20:55 (marginal, 1.08 h)	79.2° 15:00	9.42	84%	85.4°
2039-03-07 Mon	11	—	unknown	19:55–20:55 (marginal, 1.0 h)	79.2° 14:55	9.38	91%	97.3°
2039-03-08 Tue	12	—	unknown	19:55–20:05 (good, 0.17 h)	79.2° 14:55	9.33	96%	109.5°
2039-03-09 Wed	12	—	unknown	19:55–20:10 (good, 0.25 h)	79.2° 14:50	9.28	99%	121.8°
2039-03-10 Thu	11	—	unknown	19:55–20:05 (good, 0.17 h)	79.2° 14:45	9.23	100%	133.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-02-09&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.