GoodSeeing
Home › Locations › Koga

Koga

36.183° N   139.717° E  ·  17 M
7 /100
PEAK
Cloud will spoil it. Not a night for the telescope.
NO USABLE WINDOW · ASTRO DARK 02:00–04:00 · MOON 0%
Transparency
0.19
Seeing
0.88
Cloud
95%
Moon
0%

Clouded out tonight

Hour by hour, local to Koga. Colour encodes the score and nothing else; every other measurement is luminance.

Sky state
Lighter = daylight and twilight  ·  unshaded = astronomical dark
Score
02
03
04
05
0
7
0
0
Low cloud
100%
85%
100%
71%
Mid cloud
10%
14%
9%
32%
High cloud
76%
41%
48%
29%
Transparency
0.10
0.19
0.10
0.10
Seeing
0.87
0.88
0.88
0.86
Moon clear
down
down
down
down
Inspect

Cloud tracks show clear sky — a longer bar is better. The figure inside each track is the raw measurement.

Why this hour scored what it did
02 Clouded out · 0/100
Starting from
100
Cloud
−100
Transparency
−0
Seeing
−0
Moonlight
−0
Darkness
−0
Score
0
CLOUD 100% LOW 100% MID 10% HIGH 76% SUN -29.9° MOON -29.7° / 0% WIND 3 TEMP 23°
Excellent 75+ Good 55+ Fair 35+ Poor 15+ Not worth it Seeing is estimated from surface wind — see how we score.

What are you doing tonight?

The same forecast, weighted for the target. Planetary work barely cares about moonlight; long exposures die on high cloud a visual observer would never notice.

NO USABLE WINDOW FOR THIS TARGET TONIGHT

Darkness and moonlight dominate. Faint fuzzies need a genuinely dark sky more than they need steady air.

0204
CLOUD NEVER DROPS BELOW 84%
NO USABLE WINDOW FOR THIS TARGET TONIGHT

Seeing is everything and moonlight is irrelevant. Bright targets punch through twilight, so darkness barely counts.

0204
CLOUD NEVER DROPS BELOW 84%
NO USABLE WINDOW FOR THIS TARGET TONIGHT

Tolerates soft seeing, but high cloud wrecks a wide frame and moonlight raises the background everywhere.

0204
CLOUD NEVER DROPS BELOW 84%
NO USABLE WINDOW FOR THIS TARGET TONIGHT

Needs conditions to hold still for hours. Sustained transparency matters more than any single good hour.

0204
CLOUD NEVER DROPS BELOW 84%
NO USABLE WINDOW FOR THIS TARGET TONIGHT

Naked eye, whole sky. Total cloud and moonlight are the only things that count.

0204
CLOUD NEVER DROPS BELOW 84%
Advertisement
Reserved

The next week of nights

Tonight · 12 Aug
7
Clouded out
MOON 0%
Tomorrow · 13 Aug
25
Poor
MOON 1%
Friday · 14 Aug
22
Poor
MOON 5%
Saturday · 15 Aug
54
Fair
MOON 8%
21:00–22:00
Sunday · 16 Aug
34
Poor
MOON 19%
Monday · 17 Aug
43
Fair
MOON 28%
21:00–22:00
Tuesday · 18 Aug
52
Fair
MOON 37%
21:00–22:00
Advertisement
Reserved

Nearby locations

About this forecast

Conditions for Koga, Japan are computed from the MET Norway forecast model for these exact coordinates, combined with sun and moon positions we calculate directly. The score weighs cloud cover by layer, atmospheric transparency, estimated seeing, moonlight and how dark the sky actually gets. Read the full method →