Sen. Tim Kaine (D-Va.). (Reuters)

The U.S. Senate kept the lights on overnight to confirm a federal judge and one of President Obama's picks to serve on the Equal Employment Opportunity Commission as Republicans continue objecting to rules changes made in recent weeks by Democrats.

The decision to keep the Senate open overnight forced several senators to stay up late, or wake up early, to serve as the presiding officer. By tradition, the majority party taps its most junior members to lead the proceedings, usually for about an hour at a time, in order to learn the chamber's arcane procedural rules and tricks. That was the case overnight and early this morning, as eight senators in their first terms took turns leading proceedings.

Here's the schedule of senators who presided, as provided by the Senate Democratic Cloakroom:

9 p.m. - 11 p.m.: Sen. Joe Manchin III (D-W. Va.)

11 p.m. - 1 a.m.: Sen. Brian Schatz (D-Hawaii)

1 a.m. - 2 a.m.: Sen. Tammy Baldwin (D-Wis.)

2 a.m. - 3 a.m.: Sen. Joe  Donnelly (D-Ind.)

3 a.m. - 5 a.m.: Sen. Christopher Murphy (D-Conn.)

5 a.m. - 7 a.m.: Sen. Tim Kaine (D-Va.)

7 a.m. - 8 a.m.: Sen. Kay Hagan (D-N.C.)

8 a.m. - 9 a.m.: Sen. Claire McCaskill (D-Mo.)

9 a.m. - 9:45 a.m.: Sen. Angus King (I-Maine)

9:45 - 10:30 a.m.: Hagan

McCaskill, who is in her second term, was the only acting presiding officer overnight and early this morning who is not in her first term.

As an incentive for junior lawmakers forced to spend time in an often-empty chamber, the Senate distributes a "Golden Gavel Award" to senators who've spent at least 100 hours in the chair. Baldwin became the first freshman senator this year to earn her golden gavel in October.