 Greetings and welcome to the Introduction to Astronomy. In this week's Women in Astronomy we are going to talk about Hepatia of Alexandria and what her contributions were to astronomy. So let's take a look here and what we see is that Hepatia was born in the 4th century AD and was a very prominent philosopher and teacher who taught both philosophy and astronomy. Of course we have to remember that many things were the same back then. Philosophers and astronomers and scientists were all really tied together. We know that in terms of her work she edited at least one volume of Ptolemy's Almagest. That was one of the greatest works to come out of Greek astronomy and she did work on editing and editing some of that later on. So in her time she was able to do some editing on that and we know at least one volume of course it could have been more. Again many records from this time are gone so we only know based on what is left that we're able to tell. We also know that she was a mathematician and wrote a commentary on the Arithmetica and that was again a prominent mathematical work and she did a detailed commentary on that. We also know that she was known to construct astrolabes. An astrolabe an example of one of those is pictured here and those were devices that were used to determine the date and time and predict visibility of the planets and stars. So devices like this were very important. Remember we're talking long before computers and other type of electronic calculators so this was the way to be able to predict when things would be visible in the sky. So very important devices used over a thousand years ago. Now we do know that she was murdered in the year 415 and the reason for that is not completely known. This is a sketch of a future thought of maybe what happened and it was considered that it might have been to political jealousy meaning that there were different schools of philosophy and they would compete against each other and things could get rather violent and it was likely and possible that she was killed because of this. So let's go ahead and summarize a little about what we found out about Hepatia. We know that she lived in the 4th century and was a teacher and an astronomer in Alexandria. We know that she edited at least part of the Almagest written earlier by Ptolemy and we know that she was known for building astrolabes. So that concludes this lecture on Hepatia of Alexandria. We'll be back again next week to discuss another woman in astronomy. So until then, have a great day everyone and I will see you in class.