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Sun, moon and planets calculator
This webpage module provides some basic, up-to-date information on the sun, moon and planets. The intention is to provide some fun and useful information about these (and other) astronomical objects. The information presented does not take account of the observer's position on the Earth. As such, it is appropriate for people looking from low- and mid-latitudes. Observers at high latitudes (i.e., latitudes closer to the pole than, say, +60° north or -60° south) may find the descriptions of where to see the objects (e.g., "visible in the west after sunset") somewhat inaccurate.

There are a number of ways in which you can access the module. These are detailed below.

  • Bookmark the telescope-net.com home page.
    The module appears on our homepage, so you can access current information on the sun, moon and planets by adding telescope-net.com to your Favorites. In most browsers, just hold the "CTRL" key and press the "D" key.
  • Use the Google Gadget version on iGoogle.
    The module is available as a Google Gadget, which you can place on your iGoogle page. This will give you the added flexibility of being able to select which objects to display (sun, moon, Mercury, etc.), as well as the information which is shown. To add this module to your iGoogle page, please click here: Add to Google
  • Use the Google Gadget version on your own pages.
    The module is available as a Google Gadget, which you can place on webpages of your own. Please click here to make this happen: Add to Google
  • Place the "native version" of the module on webpages of your own.
    The module is easy to include in your own webpages. You can see some examples below and look at their HTML. The HTML is well documented, so it should be straightforward to change parameters. The key advantage of this method is that it allows you to get information on any astronomical object in our catalog. Please see the "Advanced usage" section below for more details.
  • Use the Facebook version in... well... Facebook.
    For those inhabiting Facebook land, you can have "Sun, moon and planets" on your Facebook application list and profile page (or any other page, if you like). You can link to it here: Add to Facebook
  • Blackboard Building Block.
    The information presented in this module is also available within the Blackboard e-learning system, as a portal module. With this building block, users can select their preferences for which objects (sun, moon, Mercury, etc.) are displayed. Please click here to download the building block for Blackboard versions 7 and 8, or click here to download the building block for Blackboard version 9.

Has this stopped working for you?

This is possibly the result of an iGoogle bug. This is currently being discussed in the iGoogle developer forum here.


What is displayed

For each object (sun, moon, etc.), the information displayed includes the constellation the object is currently in and a general description of the object's location in the sky (e.g., "visible in the sky after sunset").

If the sun is near an equinox or a solstice, this is noted. For the moon, the percentage illumination and a description of the phase (e.g., "waxing crescent") is also given. If any planet is near conjunction (very close to the sun) or opposition (opposite the sun in the sky), this is mentioned. Additionally, if Mercury or Venus is nearing "greatest elongation", this is noted. These are times when Mercury and Venus are particularly well placed for observation.

If the Moon or any of the planets lie within several degrees of each other in the sky (nominally 6°) this is noted as well.  

Advanced usage

The calculator can be directly accessed by using URLs of the form below.


The "targets" variable should be a comma-separated list of objects. Valid names are "Sun", "Moon", "Mercury", "Venus", "Mars", "Jupiter", "Saturn", "Uranus", and "Neptune". Additionally, you may specify one additional target, which can be anything; e.g., comet, asteroid, or deep-sky object. Please see the examples below. You can use any object which is in the telescope-net.com catalog. This currently includes comets, all numbered asteroids, the Messier catalog, the New General Catalog, Index Catalog, Yale Bright Star catalog and the Principal Galaxy Catalog.

The "fontpx" variable can be used to change the font size of the returned text. This defaults to 12 px.

The "extras" variable can be used to request additional information. This should be a comma-separated list of options, the valid values of which are detailed below.

  • "size" provides information on the angular size of the object. Angular sizes are not estimated for objects which appear very small (ie.g., stars and asteroids), or for comets.
  • "mag" provides information on the apparent magnitudes of the objects. This is basically a measure of an object's brightness in the sky. Brightness estimates are not provided for either the sun or moon, as this is not particularly useful for the purposes of this calculator.
  • "angdist" provides information on each object's angular distance ("elongation") from the sun, and is given in degrees.
  • "radec" provides information on each object's position. The coordinates are given in the equinox J2000.0. Note that because this calculator does not know the observer's position on the Earth, these are geocentric coordinates.
  • "bbxml" produces an XML-like output format, consumed by the Blackboard building block. This XML format has not been well thought out, and will probably change in the future. If you're interested in getting these data in a "real" XML format then please get in touch.


Future developments

It's up to you! Please get in touch if you have any requests or suggestions for additional features or objects.


Below are some examples of the module, showing objects other than the sun, moon or planets. You can see the HTML for creating these here, for Example 1, Example 2, Example 3, or Example 4. Alternatively, you will find the HTML for all three by viewing the source for this webpage in your browser.

Example 1: the asteroid 14664 Vandervelden
Example 2: comet C/2006 Q1 (McNaught) and the moon
Example 3: galaxy NGC 1672
Example 4: sun, moon and planets