UPDATE 1-Mercury Computer Q2 profit beats estimates

* Q2 EPS $0.22 vs est $0.19

* Q2 rev up 23 pct to $55.5 mln

* Sees Q3 GAAP EPS $0.16-$0.18

* Sees Q3 rev $58-$60 mln

* Shrs up 7 pct after market

Jan 25 (Reuters) - Mercury Computer Systems (MRCY.O) posted a better-than-expected quarterly profit, helped mainly by increased revenue from its defence customers.

Net income for the second quarter was $5.2 million, or 22 cents a share, compared with $1.9 million, or 9 cents a share a year ago.

Analysts on average were expecting earnings of 19 cents a share, according to Thomson Reuters I/B/E/S.

Revenue rose 23 percent to $55.5 million. Analysts were expecting $54.6 million.

For the third quarter, the company forecast earnings of 16-18 cents a share, on revenue of $58-$60 million.

Shares of the Chelmsford, Massachussets-based company were up 7 percent in trading after the bell. They closed at $17.84 on Tuesday on Nasdaq. (Reporting by Mayuresh Tungare in Bangalore; Editing by Don Sebastian)