Select Union

I have a number of tables with the general structure:

   Column   |           Type           | Modifiers
-----------+--------------------------+-----------
  timestamp | timestamp with time zone |
  value     | double precision         |
Indexes: tbl__timestamp

and I would like to find the union of the timestamps.  Something like:

select timestamp from cal_quat_1 WHERE timestamp BETWEEN '2004-02-01
00:03:30' AND '2004-02-01 00:04:00' UNION select timestamp from
cal_quat_2 WHERE timestamp BETWEEN '2004-02-01 00:03:30' AND
'2004-02-01 00:04:00' UNION select timestamp from cal_quat_4 WHERE
timestamp BETWEEN '2004-02-01 00:03:30' AND '2004-02-01 00:04:00' UNION
select timestamp from cal_quat_4 WHERE timestamp BETWEEN '2004-02-01
00:03:30' AND '2004-02-01 00:04:00' UNION select timestamp from
cal_ccd_temp WHERE timestamp BETWEEN '2004-02-01 00:03:30' AND
'2004-02-01 00:04:00';

Is there a less shorter, less redundant way of writing this?

Cheers,
Randall