Monitor bitcoin transaction confirmation timestamps Well, i'm planning on developing a graph that shows bitcoin transaction average confirmation time per hour , but i have no clue where i can get transaction confirmation timestamps. 

I'm running bitcoin core node with whole blockchain and sync up to date.

Any ideas ?
The time at which a transaction was confirmed can be found in the 4B timestamp in the block header (POSIX time encoding)

To compute average transactions confirmed/hour, you can consider the header timestamp and the number of transactions in each block in your considered timeframe. The first byte following the header represents the number of transactions in the block. However, you may want to exclude the coinbase tx from the transaction count for your purposes.

If you wish to compute the time between broadcasting and confirmation of a given transaction, you must have knowledge of when a transaction was specifically broadcast. Since this is only the case if you broadcast a tx yourself, you cannot compute this exactly. You can however, determine when a tx was first accepted to the mempool of your local node, and use that as a proxy. Bitcoind offers a tx subscription service which publishes newly accepted mempool txs over a zmq interface. By indexing these with local timestamps(time of mempool acceptance), your application can later determine the time passed to the confirmation of a previously indexed tx from a block which includes this tx and the block header timestamp.