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: 02-01 (89), 02-02 (89), 02-03 (88), 01-31 (87), 02-04 (86) — by astronomy; check the weather when the night is within four days.

2040-01-23astronomy score per night — click a bar for that night2040-02-21

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2040-01-23 Mon	24	—	unknown	19:05–23:20 (marginal, 4.25 h)	79.2° 17:45	11.04	76%	37.0°
2040-01-24 Tue	24	—	unknown	19:05–23:10 (marginal, 4.08 h)	79.2° 17:45	11.01	84%	46.7°
2040-01-25 Wed	26	—	unknown	19:05–23:05 (marginal, 4.0 h)	79.2° 17:40	10.98	90%	57.0°
2040-01-26 Thu	32	—	unknown	19:05–23:10 (marginal, 4.08 h)	79.2° 17:35	10.96	95%	67.6°
2040-01-27 Fri	40	—	unknown	19:10–20:15 (good, 1.08 h)	79.2° 17:30	10.93	98%	78.6°
2040-01-28 Sat	51	—	unknown	19:10–21:15 (good, 2.08 h)	79.2° 17:25	10.9	100%	89.6°
2040-01-29 Sun	62	—	unknown	19:10–22:20 (good, 3.17 h)	79.2° 17:25	10.87	100%	100.8°
2040-01-30 Mon	73	—	unknown	19:10–22:35 (good, 3.42 h)	79.2° 17:20	10.83	97%	112.1°
2040-01-31 Tue	87	—	unknown	19:15–22:35 (good, 3.33 h)	79.2° 17:15	10.8	93%	123.3°
2040-02-01 Wed	89	—	unknown	19:15–22:35 (good, 3.33 h)	79.2° 17:10	10.77	88%	134.3°
2040-02-02 Thu	89	—	unknown	19:15–22:35 (good, 3.33 h)	79.2° 17:05	10.74	80%	144.6°
2040-02-03 Fri	88	—	unknown	19:15–22:35 (good, 3.33 h)	79.2° 17:05	10.7	71%	153.2°
2040-02-04 Sat	86	—	unknown	19:15–22:30 (good, 3.25 h)	79.2° 17:00	10.67	61%	157.5°
2040-02-05 Sun	82	—	unknown	19:20–22:30 (good, 3.17 h)	79.2° 16:55	10.64	50%	154.8°
2040-02-06 Mon	81	—	unknown	19:20–22:25 (good, 3.08 h)	79.2° 16:50	10.6	39%	146.4°
2040-02-07 Tue	78	—	unknown	19:20–22:20 (good, 3.0 h)	79.2° 16:50	10.56	28%	135.1°
2040-02-08 Wed	76	—	unknown	19:20–22:15 (good, 2.92 h)	79.2° 16:45	10.53	18%	122.5°
2040-02-09 Thu	72	—	unknown	19:25–22:10 (good, 2.75 h)	79.2° 16:40	10.49	10%	109.1°
2040-02-10 Fri	70	—	unknown	19:25–22:10 (good, 2.75 h)	79.2° 16:35	10.45	4%	95.4°
2040-02-11 Sat	68	—	unknown	19:25–22:05 (good, 2.67 h)	79.2° 16:30	10.42	1%	81.7°
2040-02-12 Sun	66	—	unknown	19:25–22:00 (good, 2.58 h)	79.2° 16:30	10.38	0%	68.1°
2040-02-13 Mon	64	—	unknown	19:25–21:55 (good, 2.5 h)	79.2° 16:25	10.34	3%	55.1°
2040-02-14 Tue	58	—	unknown	19:30–21:55 (good, 2.42 h)	79.2° 16:20	10.3	7%	43.0°
2040-02-15 Wed	52	—	unknown	19:30–21:50 (good, 2.33 h)	79.2° 16:15	10.26	14%	32.4°
2040-02-16 Thu	43	—	unknown	19:30–21:35 (good, 2.08 h)	79.2° 16:10	10.22	22%	24.7°
2040-02-17 Fri	35	—	unknown	19:30–21:25 (good, 1.92 h)	79.2° 16:10	10.18	31%	22.4°
2040-02-18 Sat	27	—	unknown	19:35–20:55 (good, 1.33 h)	79.2° 16:05	10.14	41%	26.3°
2040-02-19 Sun	21	—	unknown	19:35–21:55 (marginal, 2.33 h)	79.2° 16:00	10.1	50%	34.1°
2040-02-20 Mon	17	—	unknown	19:35–21:45 (marginal, 2.17 h)	79.2° 15:55	10.06	60%	43.6°
2040-02-21 Tue	15	—	unknown	19:35–21:40 (marginal, 2.08 h)	79.2° 15:55	10.02	69%	53.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-01-23&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.