Mostafa, I'm not sure where you're coming from with your seemingly indignant last post. I never made any claim that the Gazelle wasn't capable of being used in the observation role because I know it was. I was replying to a post from another contributor who appeared to be unaware of the fact that the Puma was also being used.
Having spent quite a lot of time "working nights" in NI, flying the Puma in the early 1990s I'm very much aware of what the Gazelle was used for after dark. However, it definitely couldn't lift the same equipment that the Puma did at that time The equipment in use back then was far too big and heavy for a Gazelle. The Gazelle used a smaller and lighter set.