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: 09-27 (100), 09-28 (100), 09-29 (100), 09-30 (100), 10-01 (100) — by astronomy; check the weather when the night is within four days.

2027-09-27astronomy score per night — click a bar for that night2027-10-26

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-09-27 Mon	100	—	unknown	21:05–05:45 (good, 8.67 h)	79.1° 02:30	8.97	7%	120.3°
2027-09-28 Tue	100	—	unknown	21:00–05:45 (good, 8.75 h)	79.1° 02:25	9.02	2%	134.3°
2027-09-29 Wed	100	—	unknown	20:55–05:45 (good, 8.83 h)	79.1° 02:20	9.07	0%	147.7°
2027-09-30 Thu	100	—	unknown	20:50–05:45 (good, 8.92 h)	79.1° 02:20	9.12	1%	159.4°
2027-10-01 Fri	100	—	unknown	20:45–05:50 (good, 9.08 h)	79.1° 02:15	9.17	4%	165.6°
2027-10-02 Sat	100	—	unknown	20:45–05:50 (good, 9.08 h)	79.1° 02:10	9.22	10%	160.8°
2027-10-03 Sun	100	—	unknown	20:40–05:50 (good, 9.17 h)	79.1° 02:05	9.26	17%	150.5°
2027-10-04 Mon	100	—	unknown	20:40–05:50 (good, 9.17 h)	79.1° 02:05	9.31	26%	138.9°
2027-10-05 Tue	100	—	unknown	20:35–05:55 (good, 9.33 h)	79.1° 02:00	9.36	35%	127.1°
2027-10-06 Wed	100	—	unknown	20:35–05:55 (good, 9.33 h)	79.1° 01:55	9.4	44%	115.5°
2027-10-07 Thu	100	—	unknown	20:35–05:55 (good, 9.33 h)	79.1° 01:50	9.45	54%	103.9°
2027-10-08 Fri	100	—	unknown	20:35–05:55 (good, 9.33 h)	79.1° 01:45	9.5	63%	92.4°
2027-10-09 Sat	100	—	unknown	20:40–05:55 (good, 9.25 h)	79.1° 01:45	9.54	72%	80.9°
2027-10-10 Sun	100	—	unknown	21:55–06:00 (good, 8.08 h)	79.1° 01:40	9.59	80%	69.5°
2027-10-11 Mon	98	—	unknown	00:45–06:00 (good, 5.25 h)	79.1° 01:35	9.63	87%	57.9°
2027-10-12 Tue	90	—	unknown	03:45–06:00 (good, 2.25 h)	79.1° 01:30	9.68	93%	46.4°
2027-10-13 Wed	51	—	unknown	20:20–06:00 (marginal, 9.67 h)	79.1° 01:25	9.72	97%	35.0°
2027-10-14 Thu	36	—	unknown	02:25–06:05 (marginal, 3.67 h)	79.1° 01:25	9.77	99%	24.2°
2027-10-15 Fri	28	—	unknown	20:15–22:50 (marginal, 2.58 h)	79.1° 01:20	9.81	100%	15.9°
2027-10-16 Sat	32	—	unknown	20:15–23:40 (marginal, 3.42 h)	79.1° 01:15	9.85	98%	15.6°
2027-10-17 Sun	40	—	unknown	20:10–01:05 (marginal, 4.92 h)	79.1° 01:10	9.9	94%	24.0°
2027-10-18 Mon	53	—	unknown	20:10–06:05 (marginal, 9.92 h)	79.1° 01:10	9.94	88%	35.6°
2027-10-19 Tue	86	—	unknown	20:10–00:00 (good, 3.83 h)	79.1° 01:05	9.98	80%	48.3°
2027-10-20 Wed	94	—	unknown	20:10–03:50 (good, 7.67 h)	79.1° 01:00	10.02	70%	61.4°
2027-10-21 Thu	100	—	unknown	20:05–05:40 (good, 9.58 h)	79.1° 00:55	10.07	59%	74.8°
2027-10-22 Fri	100	—	unknown	20:05–06:05 (good, 10.0 h)	79.1° 00:50	10.11	48%	88.5°
2027-10-23 Sat	100	—	unknown	20:05–06:10 (good, 10.08 h)	79.1° 00:50	10.15	36%	102.2°
2027-10-24 Sun	100	—	unknown	20:00–06:15 (good, 10.25 h)	79.1° 00:45	10.19	26%	115.9°
2027-10-25 Mon	100	—	unknown	20:00–06:10 (good, 10.17 h)	79.1° 00:40	10.23	16%	129.6°
2027-10-26 Tue	100	—	unknown	20:00–06:10 (good, 10.17 h)	79.1° 00:35	10.27	9%	142.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-09-27&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.