allow iers degraded accuracy

tiagohm · Dec 22, 2024 · 2170848 · 2170848
1 parent 3715440
commit 2170848
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Showing 3 changed files with 33 additions and 12 deletions.
diff --git a/scripts/astropy/iers.py b/scripts/astropy/iers.py
@@ -5,6 +5,7 @@
 # https://docs.astropy.org/en/stable/api/astropy.utils.iers.IERS.html
 
 iers.conf.auto_download = False
+iers.conf.iers_degraded_accuracy = 'warn'
 
 t = Time('2020-10-07T12:34:56', format='isot', scale='utc')
 

diff --git a/src/iers.test.ts b/src/iers.test.ts
@@ -5,14 +5,30 @@ import { Timescale, timeYMDHMS } from './time'
 
 test('iersA', async () => {
 	await iersa.load(await Bun.file('data/finals2000A.txt').arrayBuffer())
-	const t = timeYMDHMS(2020, 10, 7, 12, 34, 56, Timescale.UTC)
+	let t = timeYMDHMS(2020, 10, 7, 12, 34, 56, Timescale.UTC)
 	expect(iersa.delta(t)).toBe(-0.17181135242592593)
 	expect(iersa.xy(t)).toEqual([arcsec(0.1878143362962963), arcsec(0.3180433324074074)])
+
+	t = timeYMDHMS(2050, 10, 7, 12, 34, 56, Timescale.UTC)
+	expect(iersa.delta(t)).toBe(0.0862207)
+	expect(iersa.xy(t)).toEqual([arcsec(0.094347), arcsec(0.293316)])
+
+    t = timeYMDHMS(1900, 10, 7, 12, 34, 56, Timescale.UTC)
+	expect(iersa.delta(t)).toBe(0.8075)
+	expect(iersa.xy(t)).toEqual([arcsec(0.143), arcsec(0.137)])
 })
 
 test('iersB', async () => {
 	await iersb.load(await Bun.file('data/eopc04.1962-now.txt').arrayBuffer())
-	const t = timeYMDHMS(2020, 10, 7, 12, 34, 56, Timescale.UTC)
+	let t = timeYMDHMS(2020, 10, 7, 12, 34, 56, Timescale.UTC)
 	expect(iersb.delta(t)).toBe(-0.17180533112962962)
 	expect(iersb.xy(t)).toEqual([arcsec(0.1878133848148148), arcsec(0.3179746625925926)])
+
+	t = timeYMDHMS(2050, 10, 7, 12, 34, 56, Timescale.UTC)
+	expect(iersb.delta(t)).toBe(0.0523072)
+	expect(iersb.xy(t)).toEqual([arcsec(0.202982), arcsec(0.338377)])
+
+    t = timeYMDHMS(1900, 10, 7, 12, 34, 56, Timescale.UTC)
+	expect(iersb.delta(t)).toBe(0.0326338)
+	expect(iersb.xy(t)).toEqual([arcsec(-0.0127), arcsec(0.213)])
 })
diff --git a/src/iers.ts b/src/iers.ts
@@ -83,18 +83,20 @@ export class IersA extends IersBase {
 		this.clear()
 
 		return readLinesFromArrayBuffer(buffer, (line) => {
-			const mjd = parseFloat(line.substring(7, 15).trim())
 			const pmXa = parseFloat(line.substring(18, 27).trim())
 			const pmYa = parseFloat(line.substring(37, 46).trim())
 			const pmXb = parseFloat(line.substring(134, 144).trim())
 			const pmYb = parseFloat(line.substring(144, 154).trim())
 			const dut1a = parseFloat(line.substring(58, 68).trim())
 			const dut1b = parseFloat(line.substring(154, 165).trim())
 
-			this.mjd.push(mjd)
-			this.pmX.push(pmXb || pmXa)
-			this.pmY.push(pmYb || pmYa)
-			this.dut1.push(dut1b || dut1a)
+			if ((pmXb || pmXa) && (pmYb || pmYa) && (dut1b || dut1a)) {
+				const mjd = parseFloat(line.substring(7, 15).trim())
+				this.mjd.push(mjd)
+				this.pmX.push(pmXb || pmXa)
+				this.pmY.push(pmYb || pmYa)
+				this.dut1.push(dut1b || dut1a)
+			}
 		})
 	}
 }
@@ -108,15 +110,17 @@ export class IersB extends IersBase {
 		return readLinesFromArrayBuffer(buffer, (line) => {
 			if (line.startsWith('#')) return
 
-			const mjd = parseFloat(line.substring(16, 26).trim())
 			const pmX = parseFloat(line.substring(26, 38).trim())
 			const pmY = parseFloat(line.substring(38, 50).trim())
 			const dut1 = parseFloat(line.substring(50, 62).trim())
 
-			this.mjd.push(mjd)
-			this.pmX.push(pmX)
-			this.pmY.push(pmY)
-			this.dut1.push(dut1)
+			if (pmX && pmY && dut1) {
+				const mjd = parseFloat(line.substring(16, 26).trim())
+				this.mjd.push(mjd)
+				this.pmX.push(pmX)
+				this.pmY.push(pmY)
+				this.dut1.push(dut1)
+			}
 		})
 	}
 }