---
title: Plotting the brightest 200 stars
format:
    html:
        copy-code: true
        embed-resources: true
fig-responsive: true
fig-width: 8
---

Here we try to replicate what we did in class but with R.

```{r}
#library(tidyverse) or you really just need to two below
library(magrittr)
library(ggplot2)
```

We begin by reading in the data,
```{r}
data <- read.csv('./brightest_200.csv', header=FALSE)
head(data)
```
and then attach meaningful column names:
```{r}
names(data) <- c("formal name", "common name", "RA", "DEC")
head(data)
```

Now we have the same issue we had in class, where the Right Ascension values are not in a format we can easily plot. As such, we need to convert them to decimal form.

```{r}
ra2decimal <- function(s) {
    hrs <- as.numeric(substr(s, 1, 2))
    mins <- as.numeric(substr(s, 4, 5))
    return (15 * (hrs + mins / 60))
}

data$RA %>% ra2decimal
```

Those look pretty good, so I'll go ahead and add another table column with those converted values.
```{r}
data$RA_decimal <- data$RA %>% ra2decimal
head(data)
```

Now we can plot! If we just did a straight Cartesian plane:
```{r}
ggplot(data=data, aes(x=RA_decimal, y=DEC)) + 
    geom_point()
```

Or if we want to try to replicate the "aitoff" projection we used in Python:
```{r}
ggplot(data=data, aes(x=RA_decimal, y=DEC)) + 
    geom_point() + 
    coord_map("aitoff")
```
which looks great, outside the the gridlines being a bit silly. But that could be tweaked.