Prepare an observation
Before the night
What is up there, and when
This page does not tell you whether the weather is good: it tells you what is up, at what time, and for how long. For the state of the sky right now, see Live.
Pick a site: everything below concerns that site alone. The two are a hundred and thirty kilometres apart, which changes the sky little and the horizon a great deal.
The sky map
Drag to look around, scroll to zoom. The map follows the clock, for this site’s sky.
What to look at tonight
The objects below are those that rise above 30° while the sky is in full darkness, longest window first. Neither condition is enough on its own: a target high in broad daylight cannot be observed, and neither can a dark sky over a target that has set.
If you already know what you are after, name it: a Messier number, M31 for instance, or a right ascension and a declination in degrees.
M31 10.6847° / +41.2687° Toulouse dome night of 19 September 2026
Back to tonight’s best targets
Through the year
How long this target stays above the threshold in full darkness, every fortnight from tonight.
Best around 19 October, with 9h 45m of full darkness above the threshold.
Observable for 8h 30m tonight, above 30° in full darkness.
- Usable window21:35 to 06:058h 30m
- Highest88°at 02:40, airmass 1.00
- Moon, at that moment107°below the horizon
What each instrument frames
Whether a target fits in the frame depends on the optical train, not on the telescope alone. These figures are computed from the focal length and the sensor, both held in the inventory.
| Optical train | Field | Compared | Sampling |
|---|---|---|---|
| A13 | 2.3 × 1.5° | 4.4× the Moon | 0.85″/px |
| L13 and ASI6200MM | |||
| T28ra | 3.3 × 2.2° | 6.5× the Moon | 1.25″/px |
| RASA and ZEUS 455 | |||
| T51 photometry | 37 × 37′ | 1.2× the Moon | 0.54″/px |
| CDK20 and C4-16000 | |||
| T51 spectroscopy | 12 × 10′ | 39% of the Moon | 0.27″/px |
| CDK20 and Atik 460EX | |||
| T28sc | 7 × 4′ | 23% of the Moon | 0.21″/px |
| ASI290MM | |||
| Covers 7′ while the Sun spans 32′: it cannot take the whole disc in one frame. | |||
| T51 planetary | 6 × 3′ | 19% of the Moon | 0.17″/px |
| ASI462MC | |||
The forecast from meteoblue
These three panels come from meteoblue, not from us. They bring what we cannot yet measure: the seeing, in arc seconds. Nothing loads before you agree, as with the videos and the maps elsewhere on this site.
Seeing in arc seconds, hour by hour, with cloud and humidity. Best values are marked.
Forecast by meteoblue, embedded from their site. Nothing loads before you agree.
General weather over the coming days, three hours at a time.
Forecast by meteoblue, embedded from their site. Nothing loads before you agree.
The week at a glance, to decide whether an evening is worth holding.
Forecast by meteoblue, embedded from their site. Nothing loads before you agree.
The sky map
Drag to look around, scroll to zoom. The map follows the clock, for this site’s sky.
What to look at tonight
The objects below are those that rise above 30° while the sky is in full darkness, longest window first. Neither condition is enough on its own: a target high in broad daylight cannot be observed, and neither can a dark sky over a target that has set.
If you already know what you are after, name it: a Messier number, M31 for instance, or a right ascension and a declination in degrees.
M31 10.6847° / +41.2687° Pic du Midi night of 19 September 2026
Back to tonight’s best targets
Through the year
How long this target stays above the threshold in full darkness, every fortnight from tonight.
Best around 19 October, with 9h 30m of full darkness above the threshold.
Observable for 8h 30m tonight, above 30° in full darkness.
- Usable window21:40 to 06:108h 30m
- Highest88°at 02:45, airmass 1.00
- Moon, at that moment107°below the horizon
What each instrument frames
Whether a target fits in the frame depends on the optical train, not on the telescope alone. These figures are computed from the focal length and the sensor, both held in the inventory.
No optical train is described for this site.
The forecast from meteoblue
These three panels come from meteoblue, not from us. They bring what we cannot yet measure: the seeing, in arc seconds. Nothing loads before you agree, as with the videos and the maps elsewhere on this site.
Seeing in arc seconds, hour by hour, with cloud and humidity. Best values are marked.
Forecast by meteoblue, embedded from their site. Nothing loads before you agree.
General weather over the coming days, three hours at a time.
Forecast by meteoblue, embedded from their site. Nothing loads before you agree.
The week at a glance, to decide whether an evening is worth holding.
Forecast by meteoblue, embedded from their site. Nothing loads before you agree.
