Telescope v0.3.0

Go wrapper around the astrometry API and image processing tools. Heavily focused around the FITS file format.

FITS Manipulation

The telescope package can be utilised to accomplish some minor manipulation of FITS data, such as cropping the data to a specific area or converting it to a preferable format.

At the moment this is limited to converting a FITS file into a much smaller image format. The primary reason for doing this is displaying the data on a web page, creating a 'copy' of the data in a JPEG or PNG format and using that instead of the FITS file is vastly preferable.

package main

import (
	"github.com/AstroStreakNet/telescope"
	"log"
)

func main() {
	// Must be .fits
	var inputFile = "file_to_convert.fits"
	// Output can be jpeg or png, simply provide a path of the desired type
	var outputPath = "file_converted.jpeg"

	err := telescope.ConvertFITS(inputFile, outputPath)
	if err != nil {
		log.Fatal(err)
	}
}

Due to the nature of FITS files this image conversion will not be a perfect representation of the actual data in the FITS file.

This conversion only grabs the data in either the primary HDU or the first non-primary HDU. For FITS files with multiple HDUs this will naturally result in an image that only has a select part of the overall data. Due to this function being designed to help display FITS images on a website, only for public consumption, this shortcoming was considered excusable.

For future iterations of this package it is hoped that the cropping of FITS files will be implemented. Furthermore, the automatic cropping of the files to capture 'streaks' is the long-term deliverable.

The header data of a fits file can be queried to collect the data points relevant to the coordinates and image configuration.

headerData := GetHeaderData("file_to_read.fits")

type HeaderData struct {
    // Coordinate
	ObsID string
    RA  string
    DEC string
    MJD float64
    // Image data
    Radius       float64
    ExposureTime float64
}

Astrometry API Interface

The Astrometry API can be interacted with through a client with inbuilt methods. This is designed to abstract away the majority of the actual API, simplifying interaction to its most basic possible functions.

Instancing a Client

A client for the nova.astrometry.net API can be instanced with the NewAstrometryClient() function.

package main

import (
	"github.com/AstroStreakNet/telescope/astrometry"
	"log"
)

func main() {
	var apiKey string = "KarshLovesWindowsAndGoogle"
	client := astrometry.NewAstrometryClient(apiKey)
}

If you are hosting your astrometry instance or have access to an alternatively hosted instance you can instead use the NewClient() function.

package main

import (
	"github.com/AstroStreakNet/telescope/astrometry"
	"log"
)

func main() {
	var baseURL string = "my.astrometry.instance/api"
	var apiKey string = "AdrianVsHR_CageFight"
	client := astrometry.NewClient(baseURL, apiKey)
}

Uploading a file

// Connect() returns session key
// Client automatically stores it, you don't have to use this return value
sessionKey, err := client.Connect()
if err != nil {
    log.Fatal(err)
}

// Uploading a file, can be any format supported by astrometry
// UploadFile() returns submission ID
// Client automatically stores it, don't have to use this return value
subID, err := c.UploadFile("./testdata/test_file.png")
if err != nil {
	log.Fatal(err)
}

It is important to note that using the Connect() function is not strictly necessary. If you have no intention of uploading files or urls with the client then do not use this function.

Connect() simply gets a session key, the astrometry session keys are only needed for uploading.

Checking Submissions

Checking a submission can be done by providing the filepath submitted. A struct will be returned depending on whether you called for a FullReview or a PartialReview.

A partial review is recommended the vast majority of the time as a full review requires many more API calls to be complete and doesn't provide anything more useful, at least in the use case that this library was designed for.

partialReview, err := c.GetPartialReview("./testdata/test_file.png")
if err != nil {
	log.Fatal(err)
}

// GetPartialReview returns PartialReview
type PartialReview struct {
    // Overview
    ID       int
    FileName string
    Finished bool
    Relevant bool
    // Tagged objects in field
    Objects []string
    // Telescope calibration
    Calibration struct {
        Parity      float64
        Orientation float64
        PixelScale  float64
        Radius      float64
        Radian      float64
        Decimal     float64
    }
}

Project Origin

Telescope was developed as a final year project for the Software Engineering program at Swinburne University of Technology.