feat: add (g *GAIAServiceClient) PerformRadialSearch() to catalog module in @observerly/skysolve

pkg/catalog/gaia.go

@@ -12,7 +12,15 @@ package catalog
 
 import (
 	"bytes"
+	"encoding/csv"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"strconv"
 	"text/template"
+
+	"github.com/observerly/skysolve/pkg/astrometry"
 )
 
 /*****************************************************************************************************************/
@@ -93,3 +101,129 @@ func (g *GAIAServiceClient) Build() (string, error) {
 }
 
 /*****************************************************************************************************************/
+
+func (g *GAIAServiceClient) PerformRadialSearch(eq astrometry.ICRSEquatorialCoordinate, radius float64, limit float64) ([]Source, error) {
+	// Set the query parameters:
+	g.Query.RA = eq.RA
+	g.Query.Dec = eq.Dec
+	g.Query.Radius = radius
+	g.Query.Limit = limit
+
+	// Construct the ADQL query from the template:
+	adqlQuery, err := g.Build()
+	if err != nil {
+		return nil, err
+	}
+
+	// Prepare the POST form data for the HTTP request:
+	formData := url.Values{}
+	formData.Set("REQUEST", "doQuery")
+	formData.Set("LANG", "ADQL")
+	formData.Set("FORMAT", "csv")
+	formData.Set("QUERY", adqlQuery)
+
+	// Send the HTTP request to the GAIA TAP service:
+	resp, err := http.PostForm(g.URI, formData)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	// Read the response body:
+	bodyBytes, _ := io.ReadAll(resp.Body)
+
+	// Check for HTTP errors and return the response body if not OK:
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("GAIA TAP query failed: %s", string(bodyBytes))
+	}
+
+	// Parse the CSV data from the response body:
+	records, err := csv.NewReader(bytes.NewReader(bodyBytes)).ReadAll()
+	if err != nil {
+		return nil, err
+	}
+
+	// Unmarshal the CSV data into our struct array:
+	var stars []Source
+
+	// Iterate over the records and extract the source star data, skipping the header row:
+	for _, record := range records[1:] {
+		ra, err := strconv.ParseFloat(fmt.Sprintf("%v", record[2]), 64)
+		if err != nil {
+			continue
+		}
+
+		dec, err := strconv.ParseFloat(fmt.Sprintf("%v", record[3]), 64)
+		if err != nil {
+			continue
+		}
+
+		pmra, err := strconv.ParseFloat(fmt.Sprintf("%v", record[4]), 64)
+		if err != nil {
+			continue
+		}
+
+		pmdec, err := strconv.ParseFloat(fmt.Sprintf("%v", record[5]), 64)
+		if err != nil {
+			continue
+		}
+
+		parallax, err := strconv.ParseFloat(fmt.Sprintf("%v", record[6]), 64)
+		if err != nil {
+			continue
+		}
+
+		flux, err := strconv.ParseFloat(fmt.Sprintf("%v", record[7]), 64)
+		if err != nil {
+			continue
+		}
+
+		mag, err := strconv.ParseFloat(fmt.Sprintf("%v", record[8]), 64)
+		if err != nil {
+			continue
+		}
+
+		// Create a new source star object:
+		star := Source{
+			UID:                       record[0],
+			Designation:               record[1],
+			RA:                        ra,
+			Dec:                       dec,
+			ProperMotionRA:            pmra,
+			ProperMotionDec:           pmdec,
+			Parallax:                  parallax,
+			PhotometricGMeanFlux:      flux,
+			PhotometricGMeanMagnitude: mag,
+		}
+
+		// Append the source star to the array:
+		stars = append(stars, star)
+	}
+
+	// Convert string fields to float64 for RA, Dec, and Magnitude:
+	for i, star := range stars {
+		ra, err := strconv.ParseFloat(fmt.Sprintf("%v", star.RA), 64)
+		if err != nil {
+			continue
+		}
+
+		dec, err := strconv.ParseFloat(fmt.Sprintf("%v", star.Dec), 64)
+		if err != nil {
+			continue
+		}
+
+		mag, err := strconv.ParseFloat(fmt.Sprintf("%v", star.PhotometricGMeanMagnitude), 64)
+		if err != nil {
+			continue
+		}
+
+		stars[i].RA = ra
+		stars[i].Dec = dec
+		stars[i].PhotometricGMeanMagnitude = mag
+	}
+
+	// Return the extracted source star data:
+	return stars, nil
+}
+
+/*****************************************************************************************************************/

pkg/catalog/gaia_test.go

@@ -0,0 +1,65 @@
+/*****************************************************************************************************************/
+
+//	@author		Michael Roberts <michael@observerly.com>
+//	@package	@observerly/skysolve
+//	@license	Copyright © 2021-2025 observerly
+
+/*****************************************************************************************************************/
+
+package catalog
+
+import (
+	"math"
+	"testing"
+
+	"github.com/observerly/skysolve/pkg/astrometry"
+)
+
+/*****************************************************************************************************************/
+
+func radians(degrees float64) float64 {
+	return degrees * math.Pi / 180.0
+}
+
+/*****************************************************************************************************************/
+
+func IsWithinICRSPolarRadius(ra, dec, r float64) bool {
+	// Clamp cosine  to the valid range [-1, 1] to prevent NaN from math.Acos and
+	// calculate the angular distance in radians:
+	d := math.Acos(math.Max(-1.0, math.Min(1.0, math.Cos(radians(dec))*math.Cos(radians(ra)))))
+	// Determine if the angular distance is within the radius R
+	return d <= radians(r)
+}
+
+/*****************************************************************************************************************/
+
+func TestQueryExecutedSuccessfully(t *testing.T) {
+	var q = NewGAIAServiceClient()
+
+	stars, err := q.PerformRadialSearch(astrometry.ICRSEquatorialCoordinate{
+		RA:  0,
+		Dec: 0,
+	}, 2.5, 10)
+
+	if err != nil {
+		t.Errorf("Failed to execute query: %v", err)
+	}
+
+	if len(stars) == 0 {
+		t.Errorf("No stars returned")
+	}
+
+	for _, star := range stars {
+		// Test that the star is within the search radius:
+		if !IsWithinICRSPolarRadius(star.RA, star.Dec, 2.5) {
+			t.Errorf("Star is not within the search radius")
+		}
+	}
+
+	// The GAIA catalog is expected to return a maximum of 116 stars for this query:
+	if len(stars) > 116 {
+		t.Errorf("Too many stars returned")
+	}
+}
+
+/*****************************************************************************************************************/