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: 08-15 (46), 08-14 (36), 08-02 (33), 08-01 (32), 07-31 (30) — by astronomy; check the weather when the night is within four days.

2028-07-17astronomy score per night — click a bar for that night2028-08-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-07-17 Mon	4	—	unknown	04:30–04:50 (marginal, 0.33 h)	72.5° 09:25	5.11	21%	1.7°
2028-07-18 Tue	6	—	unknown	04:20–04:50 (marginal, 0.5 h)	72.5° 09:20	5.15	13%	15.0°
2028-07-19 Wed	8	—	unknown	04:10–04:55 (marginal, 0.75 h)	72.5° 09:15	5.2	6%	28.7°
2028-07-20 Thu	10	—	unknown	04:05–04:10 (good, 0.08 h)	72.5° 09:10	5.25	2%	42.9°
2028-07-21 Fri	11	—	unknown	04:00–04:10 (good, 0.17 h)	72.5° 09:05	5.3	0%	57.4°
2028-07-22 Sat	13	—	unknown	03:55–04:10 (good, 0.25 h)	72.5° 09:05	5.35	1%	72.2°
2028-07-23 Sun	15	—	unknown	03:55–04:10 (good, 0.25 h)	72.5° 09:00	5.4	5%	87.1°
2028-07-24 Mon	18	—	unknown	03:50–04:15 (good, 0.42 h)	72.5° 08:55	5.45	11%	101.9°
2028-07-25 Tue	19	—	unknown	03:45–04:15 (good, 0.5 h)	72.5° 08:50	5.5	20%	116.6°
2028-07-26 Wed	21	—	unknown	03:40–04:15 (good, 0.58 h)	72.5° 08:45	5.55	30%	131.1°
2028-07-27 Thu	23	—	unknown	03:40–04:20 (good, 0.67 h)	72.5° 08:45	5.6	41%	145.3°
2028-07-28 Fri	25	—	unknown	03:35–04:20 (good, 0.75 h)	72.5° 08:40	5.66	52%	159.2°
2028-07-29 Sat	27	—	unknown	03:30–04:20 (good, 0.83 h)	72.5° 08:35	5.71	63%	172.8°
2028-07-30 Sun	28	—	unknown	03:25–04:25 (good, 1.0 h)	72.5° 08:30	5.77	73%	174.0°
2028-07-31 Mon	30	—	unknown	03:20–04:25 (good, 1.08 h)	72.5° 08:30	5.82	82%	161.0°
2028-08-01 Tue	32	—	unknown	03:20–04:25 (good, 1.08 h)	72.5° 08:25	5.88	89%	148.2°
2028-08-02 Wed	33	—	unknown	03:20–04:30 (good, 1.17 h)	72.5° 08:20	5.93	94%	135.6°
2028-08-03 Thu	30	—	unknown	03:20–04:30 (good, 1.17 h)	72.5° 08:15	5.99	98%	123.2°
2028-08-04 Fri	28	—	unknown	03:20–04:30 (good, 1.17 h)	72.5° 08:10	6.04	100%	111.0°
2028-08-05 Sat	25	—	unknown	03:25–04:35 (good, 1.17 h)	72.5° 08:10	6.1	100%	99.0°
2028-08-06 Sun	21	—	unknown	04:15–04:35 (good, 0.33 h)	72.5° 08:05	6.16	98%	87.0°
2028-08-07 Mon	17	—	unknown	02:40–04:35 (marginal, 1.92 h)	72.5° 08:00	6.21	94%	75.1°
2028-08-08 Tue	14	—	unknown	02:40–04:35 (marginal, 1.92 h)	72.5° 07:55	6.27	88%	63.3°
2028-08-09 Wed	13	—	unknown	02:40–04:40 (marginal, 2.0 h)	72.5° 07:50	6.33	82%	51.5°
2028-08-10 Thu	13	—	unknown	02:35–04:40 (marginal, 2.08 h)	72.5° 07:50	6.38	74%	39.6°
2028-08-11 Fri	15	—	unknown	02:30–04:40 (marginal, 2.17 h)	72.5° 07:45	6.44	65%	27.6°
2028-08-12 Sat	21	—	unknown	02:15–04:45 (marginal, 2.5 h)	72.5° 07:40	6.5	56%	15.4°
2028-08-13 Sun	28	—	unknown	03:40–04:45 (good, 1.08 h)	72.5° 07:35	6.56	46%	2.9°
2028-08-14 Mon	36	—	unknown	02:45–04:45 (good, 2.0 h)	72.5° 07:35	6.61	35%	9.9°
2028-08-15 Tue	46	—	unknown	02:35–04:50 (good, 2.25 h)	72.5° 07:30	6.67	26%	23.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-07-17&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.