\# astropic

The goal of astropic is to connect R to the NASA APOD API. The APOD API supports one image at a time. In order to supply more than that, this package also includes creating time ranges (of less than 2000 days at a time) and some historical data in tibble format.

Thanks to Michael W. Kearney, author of rtweet, for having a robust package based on connecting to an API. I didn’t know much about APIs when I started this project and looking at his source code helped a ton!

Credit to the APOD API contributors for all of their work in making the API, and the recent re-org.

Installation

You can install the development version from GitHub with:

# install.packages("devtools")
devtools::install_github("eringrand/astropic")

API Key

To start, you’ll need a NASA API key. If you do not have one, you can get one here. Once you put in your information, a key will be emailed to you.

Save this to your environment as NASA_KEY. e.g Sys.setenv(NASA_KEY = "YOURKEYHERE").

Query

The query parameters are described on the APOD API Github page as such…

• date A string in YYYY-MM-DD format indicating the date of the APOD image (example: 2014-11-03). Defaults to today’s date. Must be after 1995-06-16, the first day an APOD picture was posted. There are no images for tomorrow available through this API.
• concept_tags A Boolean True|False indicating whether concept tags should be returned with the rest of the response. The concept tags are not necessarily included in the explanation, but rather derived from common search tags that are associated with the description text. (Better than just pure text search.) Defaults to False.
• hd A Boolean True|False parameter indicating whether or not high-resolution images should be returned. This is present for legacy purposes, it is always ignored by the service and high-resolution urls are returned regardless.
• count A positive integer, no greater than 100. If this is specified then count randomly chosen images will be returned in a JSON array. Cannot be used in conjunction with date or start_date and end_date.
• start_date A string in YYYY-MM-DD format indicating the start of a date range. All images in the range from start_date to end_date will be returned in a JSON array. Cannot be used with date.
• end_date A string in YYYY-MM-DD format indicating that end of a date range. If start_date is specified without an end_date then end_date defaults to the current date. thumbs A Boolean parameter True|False indicating whether the API should return a thumbnail image URL for video files. If set to True, the API returns URL of video thumbnail. If an APOD is not a video, this parameter is ignored.

Example

This is a basic example to retrieve APOD data.

Returned fields

• date Date of image. Included in response because of default values.
• explanation The supplied text explanation of the image.
• hdurl The URL for any high-resolution image for that day. Will be omitted in the response IF it does not exist originally at APOD.
• media_type The type of media (data) returned. May either be ‘image’ or ‘video’ depending on content.
• service_version The service version used.
• title The title of the image.
• url The URL of the APOD image or video of the day.
• copyright The name of the copyright holder.

Basic Example

library(astropic)
get_apod() # no inputs will get today's image
#> # A tibble: 1 × 7
#>   date       explanation            hdurl media_type service_version title url  
#>   <chr>      <chr>                  <chr> <chr>      <chr>           <chr> <chr>
#> 1 2024-07-24 Our Moon doesn't real… http… image      v1              Exag… http…

Providing a date range

You can also supply a start and end date to get a range of image results back.

get_apod(query  = list(start_date = "2018-04-01", end_date = "2018-04-03"))
#> # A tibble: 3 × 8
#>   copyright       date  explanation hdurl media_type service_version title url  
#>   <chr>           <chr> <chr>       <chr> <chr>      <chr>           <chr> <chr>
#> 1 "\nFernando Ca… 2018… I love you… http… image      v1              I Br… http…
#> 2  <NA>           2018… While crui… http… image      v1              Moon… http…
#> 3 "\nSergei Maku… 2018… You may ha… http… image      v1              The … http…

Count - n random images

get_apod(query = list(count = 5))
#> # A tibble: 5 × 8
#>   copyright       date  explanation hdurl media_type service_version title url  
#>   <chr>           <chr> <chr>       <chr> <chr>      <chr>           <chr> <chr>
#> 1 "\nDamian Peac… 2015… "Astronome… http… image      v1              NGC … http…
#> 2  <NA>           1997… "This pict… http… image      v1              Look… http…
#> 3 "\nPeter Ward\… 2007… "What's ha… http… image      v1              Warp… http…
#> 4 "Tunç Tezel"    2014… "That brig… http… image      v1              Mars… http…
#> 5  <NA>           1995… "The Crab … http… image      v1              Gamm… http…

Magic

With a little magick you can also save the APOD image to your computer for use later. This is a demonstration of a picture in APOD I helped to create.

library(magick)
library(here)
library(dplyr)

save_image <- function(url){
  image <- try(magick::image_read(url), silent = FALSE)
  image_name <- gsub(".*/([^/]+$)", '\\1', m31$hdurl)
  image_loc <- here::here("man/figures/README", image_name)
  if(class(image)[1] != "try-error"){
    image %>%
    magick::image_write(image_loc)
  }
  return(image)
}

m31 <- get_apod(query = list(date = "2009-09-17"))  # only providing a start date will give the image just for that day
dplyr::pull(m31, explanation)
#> [1] "Taken by a telescope onboard NASA's Swift satellite, this stunning vista represents the highest resolution image ever made of the Andromeda Galaxy (aka M31) - at ultraviolet wavelengths. The mosaic is composed of 330 individual images covering a region 200,000 light-years wide. It shows about 20,000 sources, dominated by hot, young stars and dense star clusters that radiate strongly in energetic ultraviolet light. Of course, the Andromeda Galaxy is the closest large spiral galaxy to our own Milky Way, at a distance of some 2.5 million light-years. To compare this gorgeous island universe's appearance in optical light with its ultraviolet portrait, just slide your cursor over the image."

save_image(m31$hdurl)

Contact

Come find me on twitter @astroeringand

Code of Conduct

Please note that this project is released with a Contributor Code of Conduct. By participating in this project you agree to abide by its terms.