laurence
c6299f41ab
Preparing to merge this repository into a combined astrophotography repo. session-scripts/ becomes pipeline/ because the scripts import layout.py from their own directory and must stay together, and because 'pipeline' says what it is rather than how it came about. observing/ stays at the top level: observing plans are not processing code.
191 lines
7.2 KiB
Python
191 lines
7.2 KiB
Python
#!/usr/bin/env python3
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"""
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mo_mpc.py -- "was there a known minor planet in the frame?"
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Purpose
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-------
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The NGC 5128 (Centaurus A) LRGB session of 2026-07-21 was searched for moving
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objects (see _mo_dets.npz / _mo_tracklets.npy). Before any detection can be
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called a *new* object, we must rule out that it is simply a catalogued minor
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planet that happened to drift through the field. This script asks the
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authoritative services what known small bodies were inside the field of view at
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the epoch of the exposures.
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Field / epoch
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-------------
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Field centre : RA 13 25 27.37, Dec -43 01 10.9 (J2000)
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= 201.36404 deg, -43.01969 deg
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Field size : 42.9' x 28.6' (half-diagonal ~25.8')
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Search radius: 30 arcmin (0.5 deg) -- comfortably encloses the whole frame
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Epoch : 2026-07-21 09:22 UTC (= 2026 07 21.39), mid-luminance-sequence
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(luminance ran 08:56-10:00 UTC, session ended ~11:16 UTC)
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Observatory : Q62, iTelescope / Siding Spring Observatory
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Services queried
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----------------
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1. JPL Small-Body Identification API
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https://ssd-api.jpl.nasa.gov/sb_ident.api
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Primary source. Well documented, accepts arbitrary (including future) epochs
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because it propagates orbits rather than serving a precomputed ephemeris.
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IMPORTANT UNITS GOTCHA: despite some documentation wording, fov-ra-hwidth and
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fov-dec-hwidth are interpreted in DEGREES, not arcminutes. Passing "30"
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yields a 30-degree half-width box (the API echoes the box it used in
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["observer"]["fov_offset"], which is worth checking every run).
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Queried twice: sb-kind=a (asteroids) and sb-kind=c (comets).
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2. MPC "MPChecker" / minor planet checker
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https://minorplanetcenter.net/cgi-bin/mpcheck.cgi (classic HTTP POST form)
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https://www.minorplanetcenter.net/cgi-bin/checkmp.cgi
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Cross-check. Kept in the script even if it fails, so the log records whether
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the MPC endpoint was reachable and what it said.
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Output
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------
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Raw responses (JSON + HTML) and a human-readable summary are appended to
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intermediates/_mpc_query.txt
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Nothing is fabricated: if a service errors or refuses the epoch, the error text
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itself is written to the log.
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"""
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import json
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import math
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import sys
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import datetime
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import requests
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import layout
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# ---------------------------------------------------------------- field/epoch
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RA_SEX = "13-25-27.37"
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DEC_SEX = "M43-01-10.9" # JPL uses a leading "M" for a negative Dec
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RA_DEG = 201.36404
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DEC_DEG = -43.01969
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OBS_TIME = "2026-07-21_09:22:00"
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MPC_CODE = "Q62" # iTelescope, Siding Spring
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RADIUS_ARCMIN = 30.0
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HWIDTH_DEG = RADIUS_ARCMIN / 60.0 # = 0.5 deg; API wants DEGREES here
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VMAG_LIM = 22.0
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OUT = layout.path("_mpc_query.txt")
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log_lines = []
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def log(s=""):
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print(s)
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log_lines.append(str(s))
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# ------------------------------------------------------------------ JPL query
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def jpl(sb_kind):
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"""Query ssd-api.jpl.nasa.gov/sb_ident.api for one small-body class."""
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params = {
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"sb-kind": sb_kind, # 'a' = asteroid, 'c' = comet
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"mpc-code": MPC_CODE,
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"obs-time": OBS_TIME,
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"fov-ra-center": RA_SEX,
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"fov-dec-center": DEC_SEX,
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"fov-ra-hwidth": f"{HWIDTH_DEG}",
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"fov-dec-hwidth": f"{HWIDTH_DEG}",
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"mag-required": "true",
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"two-pass": "true",
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"vmag-lim": f"{VMAG_LIM}",
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}
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r = requests.get("https://ssd-api.jpl.nasa.gov/sb_ident.api",
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params=params, timeout=180)
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log(f"--- JPL sb_ident sb-kind={sb_kind} -> HTTP {r.status_code}")
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log(f" URL: {r.url}")
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if r.status_code != 200:
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log(" RAW: " + r.text[:2000])
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return None
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d = r.json()
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log(" observer : " + json.dumps(d.get("observer", {})))
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log(" n_first_pass : " + str(d.get("n_first_pass")))
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log(" n_second_pass: " + str(d.get("n_second_pass")))
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return d
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def show(d, label):
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"""Print the refined (second-pass) hits, falling back to first pass."""
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if d is None:
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return
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rows = d.get("data_second_pass") or []
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fields = d.get("fields_second") or []
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if not rows:
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rows = d.get("data_first_pass") or []
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fields = d.get("fields_first") or []
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log(f" [{label}] no second-pass data; showing first pass")
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log(f" fields: {fields}")
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if not rows:
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log(f" [{label}] NO OBJECTS in field.")
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return
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for row in rows:
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log(" " + " | ".join(str(x) for x in row))
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# ------------------------------------------------------------------ MPC query
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def mpchecker():
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"""Classic MPChecker POST form. Recorded even if it fails."""
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data = {
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"year": "2026", "month": "07", "day": "21.39",
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"which": "pos",
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"ra": "13 25 27.37", "decl": "-43 01 10.9",
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"TextArea": "",
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"radius": str(int(RADIUS_ARCMIN)),
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"limit": f"{VMAG_LIM}",
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"oc": MPC_CODE,
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"sort": "d", "mot": "h", "tmot": "s",
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"pdes": "u", "needed": "f", "ps": "n", "type": "p",
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}
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for url in ("https://minorplanetcenter.net/cgi-bin/mpcheck.cgi",
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"https://www.minorplanetcenter.net/cgi-bin/checkmp.cgi"):
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try:
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r = requests.post(url, data=data, timeout=120,
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headers={"User-Agent": "Mozilla/5.0 (mo_mpc.py)"})
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log(f"--- MPC POST {url} -> HTTP {r.status_code}, {len(r.text)} bytes")
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log(r.text[:8000])
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except Exception as e: # noqa: BLE001
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log(f"--- MPC POST {url} -> EXCEPTION {type(e).__name__}: {e}")
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# ----------------------------------------------------------------------- main
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if __name__ == "__main__":
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log("MPC / minor-planet field check")
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log("run at " + datetime.datetime.utcnow().isoformat() + "Z")
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log(f"field centre {RA_SEX} {DEC_SEX} (J2000) = {RA_DEG}, {DEC_DEG}")
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log(f"epoch {OBS_TIME} UTC, obs code {MPC_CODE}, "
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f"radius {RADIUS_ARCMIN}' , V<{VMAG_LIM}")
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log()
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for kind, label in (("a", "asteroids"), ("c", "comets")):
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try:
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show(jpl(kind), label)
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except Exception as e: # noqa: BLE001
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log(f" JPL {label} EXCEPTION {type(e).__name__}: {e}")
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log()
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mpchecker()
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# --- derived summary: total sky motion and position angle for JPL hits ---
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log()
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log("=== derived summary (from JPL second pass, sb-kind=a) ===")
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try:
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d = jpl("a")
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for row in (d.get("data_second_pass") or []):
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name, ra, dec = row[0], row[1], row[2]
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norm = float(row[5])
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vmag = row[6]
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dra, ddec = float(row[7]), float(row[8]) # "/h, RA rate has cos(dec)
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tot = math.hypot(dra, ddec)
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pa = math.degrees(math.atan2(dra, ddec)) % 360.0 # N through E
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log(f"{name}: RA {ra} Dec {dec} V={vmag} "
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f"{norm:.0f}\" ({norm/60:.1f}') from centre "
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f"motion {tot:.1f}\"/hr at PA {pa:.1f} deg "
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f"(dRA*cos(dec)={dra:.1f}, dDec={ddec:.1f} \"/hr)")
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except Exception as e: # noqa: BLE001
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log(f"summary EXCEPTION {type(e).__name__}: {e}")
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with open(OUT, "w", encoding="utf-8") as fh:
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fh.write("\n".join(log_lines) + "\n")
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print("\nwrote " + OUT)
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