Get your astro software here

This is a very comprehensive list of astro software compiled by Pierpaolo Ricci. All free to download, but some are shareware, trial/demo type as well. He keeps it pretty up to date, adding 15 or 20 every few months.

http://www.pierpaolori​cci.it …/downloadsoftwa​re_eng.htm

I noted some omissions of some software I find useful and have contacted him for inclusion next update.
_______________

(Updated 8 May 2014)

Thought I'd post here a much more compact list of astro software that I regularly use (marked *), and maybe if you post your recommended ones too we can make this a one-stop-shop to help others. Trying to keep it a list of free or very cheap software for those just starting out, figuring by the time you're ready to really fork out for some of the more expensive software you pretty much know what you want my then anyway.

All software below is free unless noted otherwise. I've tried to keep them grouped, but not easy as some software overlaps categories handling several things. In this case I put them in the heading I think most apt.

Session Planning:
*CCD Calculator (Win)
*Astroplanner (Win/Mac) US$45 as at 08/05/14

Polar Alignment:
Alignmaster(Win) EU$14 as at 08/05/14 - a negligible price to pay considering the hours and hours it will save you doing time-consuming drift alignment. Get polar aligned in minutes, if not seconds. Note that I no longer use this regularly. I have been using OpenPHD's drift align feature as per below.
*PHD2 (OpenPHD) (Win/Mac) - the next generation of Craig Stark's PHD (see Guiding Software below). Has new features, one of which is a useful drift align tool.
EQAlign - see link below under guiding software. Can do polar alignment as well.

Guiding Software:
*PHD2 (OpenPHD) (Win/Mac) - the next generation of Craig Stark's PHD (see PHD below). Has new features and enhancements.
PHD Guiding (Win/Mac) - by far the most popular guiding software around.
Guidemaster(Win)
Metaguide(Win) - not just for guiding, can also be used as a powerful collimation aid
EQAlign(Win)

Planetarium:
*Cartes du Ciel (Win/Mac/Linux)
C2A (Win)
Stellarium(Win/Mac/Linux)
Celestia(Win/Mac/Linux)
Jupiter 2.0 (Win) - for Jupiter moon positions
Virtual Moon Atlas (Win)
Orbitron (Win) - satellite tracking software
Where is M13? (Win) - kinda different. It's actually a 3d view of our galaxy, the Milky Way. You can put in a Messier or NGC object and it'll show where it is in relation to where our Solar System.

Image Capture:
*Sequence Generator Pro (Win) US$99 as at 08/05/14- reasonable price, very powerful and useful.
Nebulosity (Win/Mac) US$60 as at 23/10/09 - quite powerful, does image capture, stacking, and post-processing. Can also link to PHD Guiding to drizzle.
Astro Photography Tool (Win) free demo, EU$12.70 as at 6/8/10 - if you're imaging with a Canon DSLR, and if you're reading this you probably are, this one is definitely worth a look.
K3CCDTools (Win) US$49 as at 23/10/09 - more for webcam and planetary/lunar imaging, but can also drift align
Craterlet(Win/Mac) - also more for webcam and planetary/lunar imaging.

Deep Sky Image Processing:
*PixInsight (Win/Mac/Linux) EU$199 (excl VAT) - extremely powerful, specifically written for astro image processing although can be used on normal photos. Be warned, there is a steep learning curve, as the philosophy of image processing using PI is different to PhotoShop that you're probably used to. That being said, in my opinion, PI is the ultimate for astro images, and it's cheaper than PS by a mile.
Noel Carboni's Astronomy Tools Photoshop Action Set (Win/Mac) US$21.95 as at 08/05/14
Gimp (Win/Mac/*nix)
Deep Sky Stacker (Win)
Iris (Win)

Planetary Image Processing:
*Registax (Win)
AviStack(Win/Mac)

Star Trails
StarTrails (Win)
StarStaX (Mac/Win/Linux)
Star Tracer - fill in the gaps on your star trail shots, or even extend them (Win) US$35 as at 08/05/14

A very nice list Troy, I'm sure it'll help out a lot of people.

Here's some software to capture video from any camera with Live View.

Software - free:
http://sourceforge.net​/projects/eos-movrec/

Author's homepage (in Russian - use google translate)
http://valexvir.narod.​ru/

But is it suitable for astro?

ooo wow this would make an excellent sticky! Thanks for the resource, troy

Gimp is alright for final resizing or file format conversion, but because it's only 8 bits per channel I don't think it's very good for curves and level adjustments.

That's the reason I started using the free pixinsight LE, but that version is no longer available. Are there any other free image editing applications that can handle higher bit depths per channel?

troypiggo wrote in post #8875763
But is it suitable for astro?

On planets and the moon yes. Other stuff I'd say no.

Mark - agree about Gimp. I was a big advocate of it, recommending it all over the place as a free but powerful alternative to Photoshop. Then I started astrophotography. It's because of all the extreme stretching we need to do, pulling data all over the place, that the 8bits really struggles.

However I included it because it's free and certainly can be used. I figured it's a good starting point.

Gimp absolutely has a place on the list. Many of its tools are easy to use (cropping and resizing) and the one I always use in gimp is save as jpeg. You can preview the quality and it tells you how big the file will be, which is just what you need when preparing to attach an image in these forums!

Been a while since I updated the list. Where is M13 added. Pretty cool.

This is one of the best software packages I've seen for controlling the camera:

"Astro Photography Tool" or APT:
http://www.ideiki.com/​astro/

Try before you buy version, 12.70 Euro (~$16 US) for full version and well worth it. Will do mirror lockup on more recent versions of EOS (one thing I was REALLY looking for). Shutter delay. Set lists for x exposures at x settings then x exposures at x settings and so on. Live view at 5x & 10x for focusing.

Aah yes. I've seen that one and heard good things about it, but haven't used it myself. Certainly worth a mention above, though. Thanks Jeff!

Just added Troy's Astro Actions and Noel Carboni's Astronomy Tools Action Set

Jeff wrote in post #10669072
This is one of the best software packages I've seen for controlling the camera:

"Astro Photography Tool" or APT:
http://www.ideiki.com/​astro/

I couldn't agree more. I've been using this for the last few months and love it. The dark adapted interface is the best I've seen.

I also found great value in using it with an external temperature/humidity sensor ($20 on ebay). It can use ambient or exif temps as part of the filename. This was great for unmanned sets of darks.

Plus, Ivo, the developer of APT, is very responsive to his customers. A feature I requested was in the very next version. Two other features I suggested are also going to be included in the next few versions.

Just added "Star Tracer". Not sure how I missed that one as I've been aware of it for a while and thought it'd be quite useful, although don't do that many star trails myself. Yet.

Just added StarStaX star trails software. Free and available for Mac, Windows, and Linux. Lovely jubbly.