Editing The Tonight Show (section)

==Broadcasting milestones==
[[File:Johnny carson 1957.JPG|thumb|right|{{center|Johnny Carson in 1957}}]]
''The Tonight Show'' began its broadcast at 11:15&nbsp;p.m. [[Eastern Time Zone|ET]], following an affiliate's 15-minute news broadcast. As more affiliates lengthened their local news programs to 30 minutes, the show began doing two openings, one for the affiliates that began at 11:15 and another for those who joined at 11:30. By early 1965, only 43 of the 190 affiliated stations carried the entire show.<ref name="KingofTheNight">{{cite book |last=Leamer |first=Laurence |title=King of the Night: The Life of Johnny Carson |publisher=[[HarperCollins]] |page=[https://archive.org/details/kingofnightlifeo00leam/page/183 183] |year=2005 |isbn=978-0-06-084099-0 |url-access=registration |url=https://archive.org/details/kingofnightlifeo00leam/page/183 }}</ref> After February 1965, Johnny Carson refused to appear until 11:30, and Ed McMahon "hosted" the 11:15 segment. Carson was not happy with this arrangement since McMahon's monologue covered the same ground as Carson's, and he finally insisted that the show's start time be changed to 11:30. As a result, the two-opening practice was eliminated in December 1966.<ref name="EncyclopediaofTV">{{cite book |title=Encyclopedia of Television |edition=2nd |publisher=[[Museum of Broadcast Communications]] |page=2356 |year=2004 |isbn=978-1-57958-411-5}}</ref>

When the show began it was [[Broadcast television systems|broadcast]] [[Live television|live]]. On January 12, 1959, the show began to be [[videotape]]d for broadcast later on the same day, although initially the Thursday night programs were kept live.<ref name="ParrSetOnTape">{{cite news |date=January 11, 1959|title=Paar Set On Tape |newspaper= [[The Washington Post]]|page=G3 }}</ref><ref name="visitorstoTVStudios">{{cite journal |date=February 22, 1959 |title=Visitors to the TV Studios |journal=The New York Times |page=X14}}</ref> [[Color television|Color broadcasts]] began on September 19, 1960.<ref name="HollywoodTieLine">{{cite news |date=September 18, 1960 |title=Hollywood Tie-Line |newspaper=[[The Washington Post]] |page=H5}}</ref>

''The Tonight Show'' became the first American television program to broadcast with [[Multichannel television sound|MTS]] stereo sound in 1984, at first sporadically, by audio engineer Ron Estes. Regular use of MTS began in 1985. In September 1991, the show's start time was shifted by five minutes to 11:35, in order to give network affiliates the opportunity to sell additional advertising during their late local newscasts. On April 26, 1999, the show started broadcasting in [[1080i]] [[HDTV]], becoming the first American nightly talk show to be shot in that format.

On March 19, 2009, ''The Tonight Show'' became the first late-night talk show in history to have the sitting [[President of the United States]] as a guest, when President [[Barack Obama]] visited Jay Leno.

Throughout the years, the starting time and the length of ''The Tonight Show'' has changed multiple times.<ref name=tshistory>{{cite news |url=http://www.museum.tv/eotvsection.php?entrycode=tonightshow |title=The Tonight Show – The Museum of Broadcast Communications |publisher=[[The Museum of Broadcast Communications]] |access-date=January 22, 2010 |archive-date=December 5, 2010 |archive-url=https://web.archive.org/web/20101205010410/http://www.museum.tv/eotvsection.php?entrycode=tonightshow |url-status=dead }}</ref>

===First run episodes===
{| class="wikitable"
|-
! Begin date
! End date
! Nights
! Start
! End
! Notes
|-
| September 27, 1954
| October 5, 1956
| Mon–Fri
| 11:30
| 1:00
| Allen
|-
| October 8, 1956
| January 4, 1957
| Mon–Fri
| 11:30
| 12:30
| Allen
|-
| January 7, 1957
| December 30, 1966
| Mon–Fri
| 11:15{{ref label|§|§}}
| 1:00
| Allen, Paar, Carson
|-
| January 2, 1967
| September 5, 1980
| Mon–Fri
| 11:30
| 1:00
| Carson
|-
| September 8, 1980
| August 30, 1991
| Mon–Fri
| 11:30
| 12:30
| Carson
|-
| September 2, 1991
| February 6, 2014<ref name="tvbythenumbers.com">{{cite journal |url=http://tvbythenumbers.com/2010/01/10/gaspin-confirms-leno-exiting-prime-time/38260 |title=It's Official: Leno Exiting Prime-time-Ratings |journal=TV by the Numbers |date=January 10, 2010 |access-date=December 22, 2011 |archive-date=January 13, 2010 |archive-url=https://web.archive.org/web/20100113195142/http://tvbythenumbers.com/2010/01/10/gaspin-confirms-leno-exiting-prime-time/38260 |url-status=dead }}</ref>
| Mon–Fri
| 11:35
| 12:37
| Carson, Leno, O'Brien, Leno
|-
| February 17, 2014
| present
| Mon–Fri
| 11:34
| 12:37
| Fallon
|}
{{note label|§|§}} Many NBC affiliates chose not to carry the first fifteen minutes of the show during this period, instead preferring to air a local newscast from 11&nbsp;p.m. to 11:30&nbsp;p.m. As of February 1965, Carson refused to host the first 15 minutes of the program, preferring to wait until the full network was in place before delivering his opening monologue; Ed McMahon hosted the program's first 15 minutes instead. This persisted for nearly two years, until the show's start time was finally adjusted to 11:30&nbsp;p.m. in January 1967.

===Weekend repeats===
From 1965 to 1975, until the premiere of ''[[Saturday Night Live]]'', weekend repeats of ''The Tonight Show'' were staples of the NBC schedule. These repeats ran in the following time slots:

{| class="wikitable"
|-
! Begin date
! End date
! Nights
! Start
! End
! Notes
|-
| January 9, 1965
| January 1, 1967
| Sat or Sun
| 11:15
| 1:00
| Repeats, known as ''The Saturday/Sunday Tonight Show''
|-
| January 7, 1967
| September 28, 1975
| Sat or Sun
| 11:30
| 1:00
| Repeats; known as ''The Best of Carson'' and ''The Weekend Tonight Show''
|}