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 V1057 Cyg: 01-24 (17), 02-16 (17), 02-20 (17), 02-21 (17), 01-23 (16) — by astronomy; check the weather when the night is within four days.

2046-01-23astronomy score per night — click a bar for that night2046-02-21

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-01-23 Tue	16	—	unknown	19:05–19:20 (good, 0.25 h)	87.3° 13:10	11.02	97%	122.1°
2046-01-24 Wed	17	—	unknown	19:05–19:25 (good, 0.33 h)	87.2° 13:05	11.0	92%	124.8°
2046-01-25 Thu	15	—	unknown	19:05–19:20 (good, 0.25 h)	87.2° 13:00	10.97	84%	124.8°
2046-01-26 Fri	13	—	unknown	19:10–19:20 (good, 0.17 h)	87.2° 13:00	10.94	74%	122.3°
2046-01-27 Sat	13	—	unknown	19:10–19:15 (good, 0.08 h)	87.2° 12:55	10.91	64%	117.7°
2046-01-28 Sun	12	—	unknown	18:35–19:45 (marginal, 1.17 h)	87.3° 12:50	10.88	53%	111.8°
2046-01-29 Mon	11	—	unknown	19:10–19:40 (marginal, 0.5 h)	87.2° 12:45	10.85	42%	105.0°
2046-01-30 Tue	10	—	unknown	19:10–19:35 (marginal, 0.42 h)	87.2° 12:40	10.82	32%	97.7°
2046-01-31 Wed	9	—	unknown	19:15–19:35 (marginal, 0.33 h)	87.2° 12:40	10.79	22%	90.4°
2046-02-01 Thu	8	—	unknown	05:40–06:00 (marginal, 0.33 h)	87.3° 12:35	10.75	15%	83.1°
2046-02-02 Fri	9	—	unknown	05:35–06:00 (marginal, 0.42 h)	87.3° 12:30	10.72	8%	76.3°
2046-02-03 Sat	9	—	unknown	05:35–06:00 (marginal, 0.42 h)	87.2° 12:25	10.69	4%	69.9°
2046-02-04 Sun	9	—	unknown	05:30–05:55 (marginal, 0.42 h)	87.2° 12:25	10.65	1%	64.4°
2046-02-05 Mon	9	—	unknown	05:25–05:55 (marginal, 0.5 h)	87.2° 12:20	10.62	0%	59.8°
2046-02-06 Tue	10	—	unknown	05:20–06:25 (marginal, 1.08 h)	87.3° 12:15	10.58	1%	56.7°
2046-02-07 Wed	10	—	unknown	05:50–05:55 (good, 0.08 h)	87.3° 12:10	10.54	4%	55.0°
2046-02-08 Thu	11	—	unknown	05:50–05:55 (good, 0.08 h)	87.2° 12:05	10.51	8%	55.1°
2046-02-09 Fri	11	—	unknown	05:45–05:50 (good, 0.08 h)	87.2° 12:00	10.47	14%	56.8°
2046-02-10 Sat	12	—	unknown	05:40–05:50 (good, 0.17 h)	87.3° 11:55	10.43	21%	60.1°
2046-02-11 Sun	12	—	unknown	05:35–05:50 (good, 0.25 h)	87.2° 11:50	10.4	29%	64.7°
2046-02-12 Mon	14	—	unknown	05:30–05:50 (good, 0.33 h)	87.2° 11:45	10.36	38%	70.3°
2046-02-13 Tue	13	—	unknown	05:30–05:45 (good, 0.25 h)	87.2° 11:45	10.32	48%	76.8°
2046-02-14 Wed	15	—	unknown	05:25–05:45 (good, 0.33 h)	87.3° 11:40	10.28	58%	84.0°
2046-02-15 Thu	16	—	unknown	05:20–05:45 (good, 0.42 h)	87.3° 11:35	10.24	68%	91.6°
2046-02-16 Fri	17	—	unknown	05:15–05:45 (good, 0.5 h)	87.2° 11:30	10.2	78%	99.4°
2046-02-17 Sat	16	—	unknown	05:25–05:40 (good, 0.25 h)	87.2° 11:30	10.16	87%	107.1°
2046-02-18 Sun	15	—	unknown	05:20–05:40 (good, 0.33 h)	87.2° 11:25	10.12	94%	114.2°
2046-02-19 Mon	16	—	unknown	05:15–05:40 (good, 0.42 h)	87.3° 11:20	10.08	98%	120.1°
2046-02-20 Tue	17	—	unknown	05:15–05:40 (good, 0.42 h)	87.3° 11:15	10.03	100%	123.9°
2046-02-21 Wed	17	—	unknown	05:10–05:35 (good, 0.42 h)	87.2° 11:10	9.99	98%	125.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-01-23&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.