gabrielchew, I have been to
CCU several times & I assure you of two things;
1) Your documentation, no matter how legal, may not mean anything to the authorities there
2) There is little to spot at
CCU. The only flights outside the region are
LH (ends March 25) &
EK which sends A332. Otherwise you will see a chorus of 737s & A320s from various Indian carriers. You may also see several ATRs. This is on the tarmac only which is not really viewable from any grounds that you can safely be on.
I strongly recommend not attempting to take photographs at
CCU for these reasons. If you absolutely must take some photos go away from the airport, there aren't any great spotting locations at the airport anyway. Depending on the flight path you may have some luck around a mall called City Centre 2 with a telephoto lens. Again be careful, this time mall security may ask you to stop. Basically even though this is legal in India, the practice is neither understood nor appreciated by the authorities, especially in
CCU.
Recently there was a report of a media photographer being harassed in
BOM where the practice is more common;
http://www.bangaloreaviation.com/201...mumbai-police-terrorise-press.html
If the above can happen in
BOM, my suggestion is to keep your camera packed at all times in
CCU.
One more thing, if questioned by the authorities at any point in
CCU be sure to speak English regardless of what other languages you know, trust me. Sorry for the doomsaying but as a fellow enthusiast I would hate to see you meet with unnecessary hassle.
Kolkata is a historic city with many great sights, take pictures of them if you get a chance!