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A Complete Guide to the Solar System and the Night Sky
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public Observing fromLocation: Greenwich, United Kingdom edit_location_alt
north SunriseRise: 7:51  
clear_day Transit: 11:50  
SunsetSet: 15:49 south
sunny DaytimeWhat's Visible Now?

Frequently Asked Questions

Location and Timezone Features

Why the default location is Greenwich United Kingdom instead of my own location when I first access TheSkyLive.com?

When you first access TheSkyLive.com the system does not have any information about your location, so by default the location is initialized to Greenwich. You can however configure your location using the Location Picker page. If you do so, TheSkyLive.com will remember it when you will access it again.

How can I customize TheSkyLive.com in order to show relevant astronomical information based on my own location?

Use the Location Picker page. If you have cookies enabled in your browser (which is the default for most browsers) your location will be remembered every time you access the website from the same browser. If you use different browsers (e.g. you browse TheSkyLive.com on PC and also on your mobile phone, or you use both Chrome and Safari) you will need to do the same operation on each browser.

I have used the Location Picker but the location is not memorized. What can I do?

The most common reasons are: 1) cookies are disabled in your browser settings; 2) you are using a different browser than the one you used to define your location; 3) you are using an Incognito browser window.

I have selected my location, however the Timezone is wrong. What can I do?

The Timezone should be automatically determined based on your selected location. At this time it is not possible to chose a Timezone which is different from the one associated to the selected location. If the automatically selected Timezone is incorrect, please report it using the instructions below.

Astronomical Objects and Data

Why can't I find a specific Comet, Asteroid or Space Probe?

The list of Solar System objects managed by TheSkyLive.com is curated. Rather than including thousands of objects, our objective is to provide information about a reasonable selection of objects that we believe might be relevant for the vast majority of people interested in Astronomy. We are very happy to receive feedback and requests to include additional objects, please use the instructions below to do that.

Why does TheSkyLive.com say that a given object is in a different constellation than most of other sources?

Most of the times this happens because the data provided by TheSkyLive.com is compared with information collected from astrology-related sources. TheSkyLive.com data has nothing to do with astrology. When TheSkyLive.com says that a given object is inside a certain constellation, this means that the position of the object (computed using high precision data from the Jet Propulsion Laboratory) is within the boundaries of that constellation, as defined by the International Astronomical Union. In some rare circumstances - in particular when an object is close to crossing a constellation boundary - it may happen that the information provided by TheSkyLive.com is inaccurate during the span of few hours.

For many comets TheSkyLive.com provides Observed Magnitude (COBS) and Predicted Magnitude (JPL). What is the difference between the two?

Predicted Magnitude is the brightness of the comet computed using astrodynamic data and models about the comet surface brightness. Because comets have a highly dynamic nature, often times the value of Predicted Magnitude is just a rough approximation. Observed Magnitude (COBS) is instead the result of an actual and recent magnitude measurements. This data is collected and provided by the Comet Observation database (COBS) and, when available, it is much more reliable than the predicted magnitude.

Chars and Tools

I would like to know how the night sky would look like from a certain location at a certain time. Which is the best tool for that?

The ideal tool for that would be TheSkyLive.com Planetarium: it is an interactive chart of the full visible sky that helps you locate constellations and Solar System objects that are visible from a given location at a certain time.

I am planning to capture images of a faint comet or asteroid. What is the best tool I can use to locate that object among the surrounding star field?

The best tool for this task is the object's Real Time Tracker available on TheSkyLive.com. For instance you can check out the Real Time Tracker for Halley's Comet. This is a high precision sky chart that shows the movement of the object and uses photographic imagery from the Digitized Sky Survey to depict the background star field.

I am observing Jupiter and I would like to identify the Galilean Moons I am observing. How can I do that?

You can use the page dedicated to the Position of Jupiter's Galilean Moons. Here you can visualize the position of Jupiter's Moons in real time and easily identify them. You can also use that tool to predict positions in the future or visualize positions that happened in the past and you can even animate the motion and visualize the dance of the Galilean Moons while they orbit around Jupiter.

How can I compute the precise coordinates of a given object at a given date and time?

If the object is in the list of objects managed by TheSkyLive then you can use TheSkyLive Planetarium, search for the object and then change the time and date. The updated coordinates will be shown in the header section of the page.

Content and Data Usage

I would like to use some content I have found on TheSkyLive.com in a website, video, publication or other media I am producing. What should I do?

If you are going to use content, charts, maps, visualizations, screenshots taken from TheSkyLive.com it is enough that you credit and link the source where you have taken that content. Please check also the Credits section and if you have questions please contact .

Reporting Bugs and Feature Requests

How can I report bugs or feature requests?

Please use the Feedback Form or write directly to .