As a Telrad user, I find Cartes du Ciel indispensable. It has a feature that I have yet to find in any other software - a Telrad that can be placed on the sky chart using the mouse. This option allows me to `practice` finding objects, as I can position the Telrad exactly as I would at the telescope, making memorization a lot easier.

Stellarium's Telrad is "fixed" onto the centre of the screen, which means that you have to move the sky instead of the telrad - not very natural! The same goes for Starry Night (digital download 6 at least; I don't know about the "Pro" versions). SN offers many finders, none of which can be placed on the "sky" with the mouse.

I imagine a number of people won't care about or need the Telrad option, but this is only one of the many perks of CdC. Most notable is its incredible database of stars and deep-sky objects. Where else can you search for (and find) an obscure little planetary nebula - such as J 900 - for free?

It seems that the most often recommended astronomy program is Stellarium, and I think I know why - its realistic sky display is beautiful. The problem with Cartes du Ciel is... it's ugly. Its graphics are primitive and at times can look rather messy.

It's understandable why Stellarium is so popular, especially if you're new to the hobby and trying to sort out the sky. It's much easier to translate the image on the screen to the actual sky when the graphics are realistic. And then there's poor Cartes du Ciel. So much more to offer than other programs, yet so often ignored.