Cartes du Ciel (CdC) is a Planetarium Program available as freeware which
can be downloaded from the Internet. This is a very powerful programme
that has a large feature set. In common with most similar programmes
in addition to the planetarium functions it allows you to control
a telescope using the ASCOM drivers. It can also follow the position
of your telescope using the same connection.
3.10 has recently been released which contains a number of improvements
that can be seen in the news section of the site. One major addition
that I have been experimenting with since it was introduced in the
V3.9 Beta at my request is the ability for CdC to send and receive
positions from Virtual Observatory applications using the SAMP (Simple
Application Messaging Protocol) hub and protocol.
number of Virtual Observatory Applications use SAMP to allow information
to be passed from one application to another. In this case we are
constrained to position information but this still allows you to
achieve lot of interoperability.
simplest option to start with is to connect CdC to the VO programme
Aladin. The operation is quite simple - it is easier to use if you
have a large screen or two or more screens so you can see both windows
at once. The steps are as follows:
CdC and connect to your telescope if required in the normal
Aladin - you will need a broadband Internet connection to
download the data.
CdC - File - SAMP - Connect to SAMP hub (
you can set this to happen when CdC starts automatically
using File - SAMP- SAMP Setup)
little icon that looks to me a bit like a radio telescope
in the bottom right of the Aladin window should be showing
some 'radio waves' coming out of it to show it is connected
and hovering your mouse over it should show the SAMP connected
you wish you can also check in CdC by executing File
- SAMP - SAMP Status. This should show connected
and also shows the applications that are connected to the
SAMP hub. In this case it will only be Aladin but you can
have more than one application connected.
all - if you set the connection to automatic and don't feel
the need to check you don't in fact have to do anything
just open the applications.
connected the applications with SAMP you can now use the interoperability.
A couple of examples follow. A tip to remember is that Aladin does
not contain details of the planets nor the Sun.
transfer a position from CdC to Aladin
CdC to the required Position using the search or calander
or alternatively you might have it following your telescope.
click on the object who's position you want to transfer
the menu pick SAMP Send Coordinates - Aladin (You
can also transfer them to other applications if you have
them connected to the hub either individually or to all)
a lot will appear to have happened in Aladin if you had
nothing open but it should have moved to the co-ordinates
you then open a an image for instance the DSS image in Aladin
or the Simbad catalogue it should appear centred on the
position sent from CdC. If it is not centred send the position
from CdC again.
it - easy !
transfer a position the other way
Aladin to the required object for instance by typing it
in the search box.
should move to the same position automatically
you have your telescope connected it should slew to the
it - even easier
be aware that the orientation of the two displays may not be the
same and the view through your telescope may be different again.
CdC as no concept of the horizon or daylight so it is quite possible
to select objects below the horizon or select an object near the
Sun in daylight
couple of suggestions of things that you can use this for.
does not contain details of the planets - if you want to
see the star field round a planet you can send the planet
position from CdC to Aladin and it will center on the position
- the planet should be where the cursor is.
you want to image or view a quasar or other object that
is not in the CdC catalogue. Find the object in Simbad for
the bottom of the page open the Aladin Applet - it may be
best to close the original copy of Aladin but it will work
with both open.
the Aladin Applet has opened you need to right click on
the SAMP indicator and Broadcast Selected Planes CdC
( and your original copy of Aladin if still open) should
move to the position of 3C273 as well as your telescope
can download a catalogue from Vizier either full or partial
and then transfer it to CdC so the objects appear just like
other catalogues. I have found a couple of problems with
this however. First Vizier does not seem to want to talk
directly to CdC even if you have started an independent
SAMP hub. Not sure why this is but if you open TopCat as
well which will provide the hub Vizier will broadcast to
TopCat Ok. TopCat can then be used to broadcast the table to
CdC - this seems to hang at the end but the data still seems
to arrive though I have not checked for any corruption or
missing data which probably will happen on the last line.