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: 02-17 (54), 02-18 (51), 02-19 (49), 02-20 (47), 02-21 (45) — by astronomy; check the weather when the night is within four days.

2042-02-17astronomy score per night — click a bar for that night2042-03-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-02-17 Mon	54	—	unknown	19:30–21:40 (good, 2.17 h)	79.2° 16:05	10.16	8%	98.0°
2042-02-18 Tue	51	—	unknown	19:35–21:35 (good, 2.0 h)	79.2° 16:05	10.12	3%	84.2°
2042-02-19 Wed	49	—	unknown	19:35–21:30 (good, 1.92 h)	79.2° 16:00	10.08	0%	70.2°
2042-02-20 Thu	47	—	unknown	19:35–21:25 (good, 1.83 h)	79.2° 15:55	10.04	1%	56.1°
2042-02-21 Fri	45	—	unknown	19:35–21:25 (good, 1.83 h)	79.2° 15:50	9.99	4%	42.4°
2042-02-22 Sat	39	—	unknown	19:40–21:20 (good, 1.67 h)	79.2° 15:45	9.95	10%	30.0°
2042-02-23 Sun	33	—	unknown	19:40–21:05 (good, 1.42 h)	79.2° 15:45	9.91	18%	20.8°
2042-02-24 Mon	26	—	unknown	19:40–20:55 (good, 1.25 h)	79.2° 15:40	9.86	28%	19.6°
2042-02-25 Tue	20	—	unknown	19:40–20:30 (good, 0.83 h)	79.2° 15:35	9.82	39%	26.8°
2042-02-26 Wed	15	—	unknown	19:45–21:25 (marginal, 1.67 h)	79.2° 15:30	9.78	50%	37.5°
2042-02-27 Thu	12	—	unknown	19:45–21:15 (marginal, 1.5 h)	79.2° 15:25	9.73	60%	49.2°
2042-02-28 Fri	11	—	unknown	19:45–21:10 (marginal, 1.42 h)	79.2° 15:25	9.69	70%	61.0°
2042-03-01 Sat	11	—	unknown	19:45–21:10 (marginal, 1.42 h)	79.2° 15:20	9.64	79%	72.8°
2042-03-02 Sun	12	—	unknown	19:45–21:10 (marginal, 1.42 h)	79.2° 15:15	9.6	86%	84.5°
2042-03-03 Mon	14	—	unknown	19:50–19:55 (good, 0.08 h)	79.2° 15:10	9.55	92%	96.1°
2042-03-04 Tue	16	—	unknown	19:50–20:20 (good, 0.5 h)	79.2° 15:10	9.5	97%	107.5°
2042-03-05 Wed	17	—	unknown	19:50–20:25 (good, 0.58 h)	79.2° 15:05	9.46	99%	118.7°
2042-03-06 Thu	17	—	unknown	19:50–20:20 (good, 0.5 h)	79.2° 15:00	9.41	100%	129.7°
2042-03-07 Fri	15	—	unknown	19:55–20:20 (good, 0.42 h)	79.2° 14:55	9.36	99%	140.2°
2042-03-08 Sat	17	—	unknown	19:55–20:15 (good, 0.33 h)	79.2° 14:50	9.31	96%	150.0°
2042-03-09 Sun	16	—	unknown	19:55–20:20 (good, 0.42 h)	79.2° 14:50	9.27	92%	157.8°
2042-03-10 Mon	14	—	unknown	19:55–20:15 (good, 0.33 h)	79.2° 14:45	9.22	86%	161.2°
2042-03-11 Tue	11	—	unknown	20:00–20:10 (good, 0.17 h)	79.2° 14:40	9.17	78%	157.9°
2042-03-12 Wed	10	—	unknown	20:00–20:10 (good, 0.17 h)	79.2° 14:35	9.12	70%	149.9°
2042-03-13 Thu	9	—	unknown	20:00–20:05 (good, 0.08 h)	79.2° 14:30	9.07	60%	139.6°
2042-03-14 Fri	7	—	unknown	19:30–20:30 (marginal, 1.0 h)	79.2° 14:30	9.02	50%	128.3°
2042-03-15 Sat	5	—	unknown	20:05–20:25 (marginal, 0.33 h)	79.2° 14:25	8.97	40%	116.2°
2042-03-16 Sun	5	—	unknown	19:30–19:55 (marginal, 0.42 h)	79.2° 14:20	8.92	30%	103.6°
2042-03-17 Mon	4	—	unknown	20:05–20:20 (marginal, 0.25 h)	79.2° 14:15	8.87	20%	90.3°
2042-03-18 Tue	3	—	unknown	20:05–20:15 (marginal, 0.17 h)	79.2° 14:15	8.82	11%	76.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-02-17&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.