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: 01-24 (100), 01-25 (100), 01-26 (100), 01-27 (100), 01-28 (100) — by astronomy; check the weather when the night is within four days.

2027-01-22astronomy score per night — click a bar for that night2027-02-20

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-01-22 Fri	65	—	unknown	19:05–22:10 (good, 3.08 h)	79.1° 17:50	11.06	100%	94.8°
2027-01-23 Sat	83	—	unknown	19:05–23:00 (good, 3.92 h)	79.1° 17:45	11.04	97%	109.4°
2027-01-24 Sun	100	—	unknown	19:05–23:05 (good, 4.0 h)	79.1° 17:40	11.01	92%	123.5°
2027-01-25 Mon	100	—	unknown	19:05–23:00 (good, 3.92 h)	79.1° 17:40	10.98	84%	137.1°
2027-01-26 Tue	100	—	unknown	19:05–23:00 (good, 3.92 h)	79.1° 17:35	10.95	75%	149.6°
2027-01-27 Wed	100	—	unknown	19:10–23:00 (good, 3.83 h)	79.1° 17:30	10.92	65%	160.2°
2027-01-28 Thu	100	—	unknown	19:10–23:00 (good, 3.83 h)	79.1° 17:25	10.89	55%	165.7°
2027-01-29 Fri	98	—	unknown	19:10–22:55 (good, 3.75 h)	79.1° 17:20	10.86	45%	161.6°
2027-01-30 Sat	96	—	unknown	19:10–22:50 (good, 3.67 h)	79.1° 17:20	10.83	36%	152.4°
2027-01-31 Sun	93	—	unknown	19:15–22:45 (good, 3.5 h)	79.1° 17:15	10.8	27%	141.7°
2027-02-01 Mon	91	—	unknown	19:15–22:40 (good, 3.42 h)	79.1° 17:10	10.77	19%	130.6°
2027-02-02 Tue	89	—	unknown	19:15–22:40 (good, 3.42 h)	79.1° 17:05	10.73	12%	119.3°
2027-02-03 Wed	88	—	unknown	19:15–22:35 (good, 3.33 h)	79.1° 17:00	10.7	7%	108.0°
2027-02-04 Thu	86	—	unknown	19:15–22:30 (good, 3.25 h)	79.1° 17:00	10.66	3%	96.5°
2027-02-05 Fri	82	—	unknown	19:20–22:25 (good, 3.08 h)	79.1° 16:55	10.63	0%	85.0°
2027-02-06 Sat	80	—	unknown	19:20–22:25 (good, 3.08 h)	79.1° 16:50	10.59	0%	73.3°
2027-02-07 Sun	77	—	unknown	19:20–22:20 (good, 3.0 h)	79.1° 16:45	10.56	2%	61.6°
2027-02-08 Mon	74	—	unknown	19:20–22:15 (good, 2.92 h)	79.1° 16:45	10.52	5%	49.9°
2027-02-09 Tue	67	—	unknown	19:25–22:10 (good, 2.75 h)	79.1° 16:40	10.49	10%	38.2°
2027-02-10 Wed	58	—	unknown	19:25–22:05 (good, 2.67 h)	79.1° 16:35	10.45	17%	27.0°
2027-02-11 Thu	48	—	unknown	19:25–21:50 (good, 2.42 h)	79.1° 16:30	10.41	25%	17.5°
2027-02-12 Fri	39	—	unknown	19:25–21:40 (good, 2.25 h)	79.1° 16:25	10.37	35%	14.6°
2027-02-13 Sat	28	—	unknown	19:25–20:10 (good, 0.75 h)	79.1° 16:25	10.33	46%	21.6°
2027-02-14 Sun	20	—	unknown	19:30–22:10 (marginal, 2.67 h)	79.1° 16:20	10.3	57%	33.0°
2027-02-15 Mon	17	—	unknown	19:30–22:00 (marginal, 2.5 h)	79.1° 16:15	10.26	68%	45.9°
2027-02-16 Tue	17	—	unknown	19:30–21:50 (marginal, 2.33 h)	79.1° 16:10	10.22	78%	59.6°
2027-02-17 Wed	19	—	unknown	19:30–21:50 (marginal, 2.33 h)	79.1° 16:05	10.18	87%	73.8°
2027-02-18 Thu	23	—	unknown	19:35–19:55 (good, 0.33 h)	79.1° 16:05	10.13	94%	88.2°
2027-02-19 Fri	29	—	unknown	19:35–21:05 (good, 1.5 h)	79.1° 16:00	10.09	98%	102.7°
2027-02-20 Sat	35	—	unknown	19:35–21:15 (good, 1.67 h)	79.1° 15:55	10.05	100%	117.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-01-22&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.