Candling Techiniques - How to hold...?

[enggass]

How is the best way to hold the egg when candling by hand? Pointy end down? Sideways? Does anyone know of a thread showing the technique?
Also, at what point should the air sac be visible? Can you see an air sac on a new fertile egg or store bought egg?
Thanks.

 

[madamwlf]

Personally I don't hold my eggs to candle. I candle them while they are in the incubator. My flashlight is bright enough that I can see what I need to. I just don't trust myself not to drop one.

 

[enggass]

Ok. On what day does the air sac start to become visible?