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: 01-21 (22), 01-19 (20), 01-22 (20), 01-18 (19), 01-20 (19) — by astronomy; check the weather when the night is within four days.

2030-01-17astronomy score per night — click a bar for that night2030-02-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-01-17 Thu	17	—	unknown	19:00–19:25 (good, 0.42 h)	87.3° 13:35	11.18	97%	105.7°
2030-01-18 Fri	19	—	unknown	19:00–19:30 (good, 0.5 h)	87.3° 13:30	11.16	99%	112.6°
2030-01-19 Sat	20	—	unknown	19:00–19:30 (good, 0.5 h)	87.3° 13:25	11.13	100%	118.7°
2030-01-20 Sun	19	—	unknown	19:00–19:30 (good, 0.5 h)	87.3° 13:20	11.11	98%	123.6°
2030-01-21 Mon	22	—	unknown	19:00–19:35 (good, 0.58 h)	87.3° 13:20	11.08	94%	126.7°
2030-01-22 Tue	20	—	unknown	19:05–19:35 (good, 0.5 h)	87.3° 13:15	11.05	88%	127.5°
2030-01-23 Wed	18	—	unknown	19:05–19:30 (good, 0.42 h)	87.3° 13:10	11.03	80%	125.9°
2030-01-24 Thu	17	—	unknown	19:05–19:25 (good, 0.33 h)	87.3° 13:05	11.0	70%	121.9°
2030-01-25 Fri	15	—	unknown	19:05–19:20 (good, 0.25 h)	87.3° 13:00	10.97	59%	116.1°
2030-01-26 Sat	13	—	unknown	19:10–19:20 (good, 0.17 h)	87.3° 13:00	10.94	48%	108.9°
2030-01-27 Sun	13	—	unknown	19:10–19:15 (good, 0.08 h)	87.3° 12:55	10.91	37%	100.8°
2030-01-28 Mon	12	—	unknown	18:35–19:45 (marginal, 1.17 h)	87.3° 12:50	10.88	26%	92.2°
2030-01-29 Tue	11	—	unknown	19:10–19:40 (marginal, 0.5 h)	87.3° 12:45	10.85	17%	83.6°
2030-01-30 Wed	10	—	unknown	19:10–19:35 (marginal, 0.42 h)	87.3° 12:40	10.82	9%	75.2°
2030-01-31 Thu	9	—	unknown	19:15–19:35 (marginal, 0.33 h)	87.3° 12:40	10.79	4%	67.5°
2030-02-01 Fri	9	—	unknown	05:40–06:00 (marginal, 0.33 h)	87.3° 12:35	10.76	1%	61.0°
2030-02-02 Sat	9	—	unknown	05:35–06:00 (marginal, 0.42 h)	87.3° 12:30	10.72	0%	56.1°
2030-02-03 Sun	9	—	unknown	05:35–06:00 (marginal, 0.42 h)	87.3° 12:25	10.69	2%	53.2°
2030-02-04 Mon	8	—	unknown	05:30–05:55 (marginal, 0.42 h)	87.3° 12:20	10.65	6%	52.5°
2030-02-05 Tue	9	—	unknown	05:25–05:55 (marginal, 0.5 h)	87.3° 12:20	10.62	12%	54.1°
2030-02-06 Wed	10	—	unknown	05:20–06:25 (marginal, 1.08 h)	87.3° 12:15	10.58	19%	57.5°
2030-02-07 Thu	10	—	unknown	05:50–05:55 (good, 0.08 h)	87.3° 12:10	10.55	27%	62.3°
2030-02-08 Fri	11	—	unknown	05:50–05:55 (good, 0.08 h)	87.3° 12:05	10.51	36%	68.1°
2030-02-09 Sat	11	—	unknown	05:45–05:50 (good, 0.08 h)	87.3° 12:00	10.48	45%	74.5°
2030-02-10 Sun	12	—	unknown	05:40–05:50 (good, 0.17 h)	87.3° 11:55	10.44	54%	81.4°
2030-02-11 Mon	12	—	unknown	05:35–05:50 (good, 0.25 h)	87.3° 11:50	10.4	64%	88.6°
2030-02-12 Tue	14	—	unknown	05:30–05:50 (good, 0.33 h)	87.3° 11:45	10.36	72%	95.9°
2030-02-13 Wed	13	—	unknown	05:30–05:45 (good, 0.25 h)	87.3° 11:45	10.32	81%	103.2°
2030-02-14 Thu	14	—	unknown	05:25–05:45 (good, 0.33 h)	87.3° 11:40	10.28	88%	110.2°
2030-02-15 Fri	13	—	unknown	05:30–05:45 (good, 0.25 h)	87.3° 11:35	10.24	94%	116.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-01-17&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.