stories that only you two can share with us. it has just been remarkable. as we have said before, we all owe you a great deal of gratitude for all you do to make a difference. thank you very much, and we want to thank you all for coming as well. this is going to be on c-span's website if you would like to see more work refer someone to a -- see more or refer someone to act. thank you for coming out. [applause] [captions copyright national cable satellite corp. 2019] [captioning performed by the national captioning institute, which is responsible for its caption content and accuracy. visit ncicap.org] announcer: you are watching american history tv, all weekend, every weekend on c-span3. announcer: located 10 miles from san luis obispo, we traveled to avila beach to see the point san luis lighthouse.

>> the town of avila beach, right over here, is pretty much a case study of the entire state of california. not only do we have native liveds, the chumash, who out here for 10,000 years, we also have a spanish mission, which is what the town of san luis obispo was built around. avila beach was the entrance to and from that town when people would come by the sea. the importance of the town of avila beach stems from the 1870's, when a lot of the piers were constructed. the hartford peer is still open today. it allowed steamships from san francisco, los angeles, anywhere in the world to come into our harbor. they could bring people, supplies. a good example of that type of

commerce is that the early missions here would sell tallow and hides from cattle. you had small sailing ships coming from boston. they would pick up those hides and bring them back to boston and make shoes out of it. you have people in boston wearing shoes made from leather that came from the central coast. there was a huge connection between our tiny town and a wider national audience. before that, a lot of oil exportation coming from our town from the center marino oil fields. all that oil was exported through our town. they felt the need to have a lighthouse, so they decided -- congress finally appropriated funds for the construction of our lighthouse at point san luis at the northern end of san luis bay. they constructed those around 1889, operational by 1890. this is the point san luis lighthouse.

, victorian story structure, again constructed in the winter of 1889, operational and lived in by 1890. one of the things we like to show on our tour is the level of craftsmanship that went into the construction. banister, madesh by hand on site. you look up, you see the crown not to, which we opted repaint, just to show people how beautiful the craftsmanship was. the entire structure has been restored completely by the point san luis lighthouse keepers. that is the nonprofit group who manages the site and oversees the restoration efforts. they were originally a group of volunteers in the early 1990's who saw a structure that needed some love and help. after the coast guard automated the station out here, they

boarded up the windows and left. what happened is these volunteers saw a building in need and decided they were going to restore it. it was led by volunteers. foundational repair, raising funds to pay for the general reconstruction. ,ven from some of the images this is from the 1990's. it needed a little bit of work. there is quite a bit to do. luckily this building has a lot of fortitude. you look down, we have great redwoods lorries. there is all growth redwood foundation in the basement. it is a starting home. lighthousean active and a federal building. this was the kitchen. this was always considered the heart of the home. eat in here,would

from all the recollections we have from them. they did have storage areas, including a basement, which is very rare on the central coast of california. they had a basement because they were storing months of supplies at a time. they would keep them all down there. they would get a supply ship every couple of months, dry goods, things like that. they would store them. it is quite chilly down there. did come with a formal dining room. guests,s if they had they would use this room. anry once in a while, inspector from san francisco, the 12th district of lighthouse service, an inspector would take a look at the house, make sure the station was running smoothly

, the supplies are not being squandered, and that people are getting along. it was a federal working site. as beautiful as the home is, you have to think of this as a working station. all the accounts from the children who live here and adults and people who visited was that it was a nice accommodation, not a cramped quarters as far as lighthouses go. and said in a beautiful, pristine location. lens, what original is called a fourth order fore nell. fourth order is just the size of the lens. a first order is giant and a sixth order is the size of a large football. a fourth order lens can go out around 15 to 20 miles, depending on the clarity of the night it can go farther. we are fortunate to have our original lens.

this was in the tower until the 1960's. it was designed by a man named augustine frenell, a french engineer who died very young, but he was the one who decided to use these pieces of glass. bullseye lenses are the wide, round once and on top and below are the prisms. each prism is set in the grass at a distinct angle, which captures the light source within the lens and shoot it out into a concentrated beam. if you take a light source such as a large oil lamp or a 500 watt light bulb, you could see it a couple miles out. if you put a light source like that inside a frenell lens, it will shoot that beam out around 20 miles on a clear night, which revolutionized lighthouses around the world. designs werenell's

active in the 1840's through the 1860's. most lighthouses in the world were getting lenses such as this. the point san luis lighthouse has had a very storied past. tucked away in san luis bay in the central coast. it is important for the general public to see it, see this beautiful, historic place and learn about the history of the lighthouse and the towns around it and the central coast. san luis obispo, california, is one of the many cities we have toured. to see more of our visit to san luis obispo and other cities across the country, go to c-span.org/citiestour. you are watching american history tv, all weekend, every weekend on c-span3. announcer: this weekend, science

gives antalia holt illustrated talk about women mathematicians and engineers recruited in the 1940's and 1950's to work at the jet propulsion laboratory. here is a preview. on december 31, 1958, the group assembles to launch explorer one. there are many women who are part of this launch but none is more important than barbara paulson. she is the one responsible for calculating the trajectory of the satellite as it leaves earth. this, she is sitting at a light table with paper and pencil. she's doing this all by hand. standing over her shoulder is richard feynman and we do bridge. everyone in the room is waiting on her calculations to find out if this mission will be a success. when she calculates that yes,

explorer one has made it, america has its first satellite. the room erupts in celebration. it is an incredible moment. it is also the birth of nasa. after explorer one, everything changes. leave military design behind and are focused on space. >> learn more about the rocket girls recruited in the 1940's and 50's to work at the jet propulsion laboratory this sunday at 9:00 eastern here on american history tv. on lectures in history, a professor teaches a class on how the cold war influenced and was influenced by photography. he talks about the perceived documentary nature of photography and how this idea was manipulated during the cold war. use ofy's lead use -- doctored photos, for example.