Hubble’s Constant: Supernovas

Data details

There are 36 rows and 3 columns. The data source¹ is used to create our data that is stored in our pins table. You can access this pin from a connection to posit.byui.edu using hathawayj/hubbles_constant_supernovas.

This data is available to all.

Variable description

• Supernova: A unique key for each supernova
• Velocity: Recession velocity from earth (km/sec)
• Distance: Distance from Earth (megaparsecs)

Variable summary

Variable type: numeric

skim_variable	n_missing	complete_rate	mean	sd	p0	p25	p50	p75	p100	hist
Velocity	0	1	12745.06	6481.21	4124	7851.25	11363.50	15847.00	30253	▇▅▅▂▁
Distance	0	1	178.18	94.92	56	113.35	155.15	235.95	467	▇▅▃▁▁

Variable type: character

skim_variable	n_missing	complete_rate	min	max	empty	n_unique	whitespace
Supernova	0	1	8	9	0	36	0

library(tidyverse)
library(pins)
library(connectapi)

hubbles_constant_supernovas <- read_csv('https://github.com/byuistats/data/raw/master/HubblesConstant-Supernovas/HubblesConstant-Supernovas.csv')


# Publish the data to the server with Bro. Hathaway as the owner.
board <- board_connect()
pin_write(board, hubbles_constant_supernovas, type = "parquet", access_type = "all")

pin_name <- "hubbles_constant_supernovas"
meta <- pin_meta(board, paste0("hathawayj/", pin_name))
client <- connect()
my_app <- content_item(client, meta$local$content_id)
set_vanity_url(my_app, paste0("data/", pin_name))

Access data

This data is available to all.

Direct Download: hubbles_constant_supernovas.parquet

R and Python Download:

URL Connections:

For public data, any user can connect and read the data using pins::board_connect_url() in R.

library(pins)
url_data <- "https://posit.byui.edu/data/hubbles_constant_supernovas/"
board_url <- board_connect_url(c("dat" = url_data))
dat <- pin_read(board_url, "dat")

Use this custom function in Python to have the data in a Pandas DataFrame.

import pandas as pd
import requests
from io import BytesIO

def read_url_pin(name):
  url = "https://posit.byui.edu/data/" + name + "/" + name + ".parquet"
  response = requests.get(url)
  if response.status_code == 200:
    parquet_content = BytesIO(response.content)
    pandas_dataframe = pd.read_parquet(parquet_content)
    return pandas_dataframe
  else:
    print(f"Failed to retrieve data. Status code: {response.status_code}")
    return None

# Example usage:
pandas_df = read_url_pin("hubbles_constant_supernovas")

Authenticated Connection:

Our connect server is https://posit.byui.edu which you assign to your CONNECT_SERVER environment variable. You must create an API key and store it in your environment under CONNECT_API_KEY.

Read more about environment variables and the pins package to understand how these environment variables are stored and accessed in R and Python with pins.

library(pins)
board <- board_connect(auth = "auto")
dat <- pin_read(board, "hathawayj/hubbles_constant_supernovas")

import os
from pins import board_rsconnect
from dotenv import load_dotenv
load_dotenv()
API_KEY = os.getenv('CONNECT_API_KEY')
SERVER = os.getenv('CONNECT_SERVER')

board = board_rsconnect(server_url=SERVER, api_key=API_KEY)
dat = board.pin_read("hathawayj/hubbles_constant_supernovas")

Footnotes

1. Wendy L. Freedman et al. Final results from the hubble space telescope key project to measure the hubble constant. The Astrophysical Journal, 553:43-72, May 20, 2001.