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 Seven Sisters: 08-13 (38), 08-12 (31), 08-01 (30), 07-31 (28), 08-02 (28) — by astronomy; check the weather when the night is within four days.

2039-07-15astronomy score per night — click a bar for that night2039-08-13

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-07-15 Fri	2	—	unknown	04:40–04:50 (marginal, 0.17 h)	72.5° 09:35	4.99	24%	8.7°
2039-07-16 Sat	3	—	unknown	04:30–04:50 (marginal, 0.33 h)	72.5° 09:30	5.03	17%	8.3°
2039-07-17 Sun	4	—	unknown	04:25–04:50 (marginal, 0.42 h)	72.5° 09:25	5.08	10%	18.5°
2039-07-18 Mon	6	—	unknown	04:20–04:50 (marginal, 0.5 h)	72.5° 09:20	5.12	5%	29.9°
2039-07-19 Tue	7	—	unknown	04:10–04:50 (marginal, 0.67 h)	72.5° 09:20	5.17	2%	41.7°
2039-07-20 Wed	8	—	unknown	04:10–04:55 (marginal, 0.75 h)	72.5° 09:15	5.22	0%	53.8°
2039-07-21 Thu	10	—	unknown	04:05–04:10 (good, 0.08 h)	72.5° 09:10	5.27	0%	66.0°
2039-07-22 Fri	11	—	unknown	04:00–04:10 (good, 0.17 h)	72.5° 09:05	5.31	3%	78.4°
2039-07-23 Sat	13	—	unknown	03:55–04:10 (good, 0.25 h)	72.5° 09:00	5.36	7%	91.1°
2039-07-24 Sun	16	—	unknown	03:55–04:15 (good, 0.33 h)	72.5° 09:00	5.41	13%	103.9°
2039-07-25 Mon	18	—	unknown	03:50–04:15 (good, 0.42 h)	72.5° 08:55	5.47	21%	117.0°
2039-07-26 Tue	20	—	unknown	03:45–04:15 (good, 0.5 h)	72.5° 08:50	5.52	30%	130.2°
2039-07-27 Wed	21	—	unknown	03:40–04:15 (good, 0.58 h)	72.5° 08:45	5.57	41%	143.7°
2039-07-28 Thu	24	—	unknown	03:35–04:20 (good, 0.75 h)	72.5° 08:45	5.62	52%	157.2°
2039-07-29 Fri	25	—	unknown	03:35–04:20 (good, 0.75 h)	72.5° 08:40	5.68	64%	170.1°
2039-07-30 Sat	27	—	unknown	03:30–04:20 (good, 0.83 h)	72.5° 08:35	5.73	74%	171.2°
2039-07-31 Sun	28	—	unknown	03:25–04:25 (good, 1.0 h)	72.5° 08:30	5.78	84%	158.2°
2039-08-01 Mon	30	—	unknown	03:30–04:25 (good, 0.92 h)	72.5° 08:25	5.84	92%	143.9°
2039-08-02 Tue	28	—	unknown	03:25–04:25 (good, 1.0 h)	72.5° 08:25	5.89	97%	129.4°
2039-08-03 Wed	27	—	unknown	03:25–04:30 (good, 1.08 h)	72.5° 08:20	5.95	100%	114.9°
2039-08-04 Thu	23	—	unknown	03:30–04:30 (good, 1.0 h)	72.5° 08:15	6.01	100%	100.6°
2039-08-05 Fri	19	—	unknown	04:10–04:30 (good, 0.33 h)	72.5° 08:10	6.06	97%	86.6°
2039-08-06 Sat	17	—	unknown	02:45–04:35 (marginal, 1.83 h)	72.5° 08:05	6.12	92%	73.0°
2039-08-07 Sun	14	—	unknown	02:45–04:35 (marginal, 1.83 h)	72.5° 08:05	6.18	85%	59.8°
2039-08-08 Mon	14	—	unknown	02:40–04:35 (marginal, 1.92 h)	72.5° 08:00	6.23	77%	47.0°
2039-08-09 Tue	14	—	unknown	02:35–04:40 (marginal, 2.08 h)	72.5° 07:55	6.29	68%	34.6°
2039-08-10 Wed	18	—	unknown	02:25–04:40 (marginal, 2.25 h)	72.5° 07:50	6.35	58%	22.6°
2039-08-11 Thu	23	—	unknown	04:25–04:40 (good, 0.25 h)	72.5° 07:50	6.4	49%	11.5°
2039-08-12 Fri	31	—	unknown	03:00–04:45 (good, 1.75 h)	72.5° 07:45	6.46	40%	6.2°
2039-08-13 Sat	38	—	unknown	02:50–04:45 (good, 1.92 h)	72.5° 07:40	6.52	30%	15.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-07-15&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.