I once heard from my rabbi in high school that it was about 3 seconds. Not sure the source,  but it always made sense to me. Witnesses also must recite their identical testimony within that same timeframe. 

Shalom alecha rebbi (u'mori)
The objective is to make a spherical-typed (360 degrees) panoramic photo,
With 2:1 aspect ratio, and its dimensions are 1024x512 or 2048x1024.

Tried searching in Google but still don't know where to start.
Please describe a step by step guide.

Possible questions :
What are the needed tools for taking the photos ?
How many photos needed to be taken ?
What is the best software for stitching those photos ?
And how to use it ?  

If there are anything I missed, please mention it.
Thank you very much !

Update :
I want to make an Android application that displays virtual tours with spherical panoramas.
In one scene, there is something like a ball / sphere, with the camera inside, on its center, and the user can look freely in 3-dimensional 360 degrees.

I'm using PanoramaGL for Android (https://code.google.com/p/panoramagl-android/), by Javier Baez.
The sample panoramic photo looks like this : (Photos by Geovanny Raura)
http://imgur.com/4VW66IV,rZm8pB5,4hhwJEc (There are 3 images)
