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Close approach of 2010 XC15
CNEOS predicts that the NEO 2010 XC15 will make a close approach on 2022-Dec-27 18:15 ± < 00:01 UT at a distance of 0.00516 AU. H=21.4 magnitude, V relative =10.10 km/sec, 'Rarity'=3, Condition Code=1. This is a decent sized rock, 140m-310m.

The close approach is quite a ways off, but since it's a 'Rarity'=3 event I thought that it deserved an early warning. I haven't done any calculations in ST4v yet.

Clear skies,

Phil S.
Nice catch. Thanks for the advanced notice. I ran it using elements for a few hours b4 close pass (Dec 27, 00:00CST - Horizons). Best time for me begins ~4am with this large rock moving 2.3'/min thru Bootes at magnitude 13.5. Its altitude is 42° and continues to rise to 63° until the encroachment of Astronomical twilight at 5:50. It's well placed in the east out of community light pollution and no Moon interference. This big rock is marked on my calendar.

Horizons (JPL) and the Minor Planet Center have the positions diverging by only 10-15 arc seconds over the few hours between my window and closest approach.
With a Condition Code=1, I would expect the orbit to be well defined. JPL & MPC should agree. Are you using the elements for 2022 August 9 or the MPC's Elements for NEOs for Today's Epoch? I noticed a slight difference between the ephemerides using those 2 epochs 2022-8-9 & 2022-11-4).

You might try giving it a look a day or 2 earlier than that, if possible. It should be brighter than 15 magnitude & visible in your 13". As always, weather permitting.

Clear skies,

Phil S.
The elements I'm using are for epoch 2022 Dec. 27.5UT and are only very slightly different for that date JPL vs MPC. Estimated positional difference is ~10" south for the JPL position. Mag 13.5 should be visible in my 13" if sky conditions allow.

I reran the ephem. Again, it's brightest and highest for me on the dark side of morning astronomical twilight of the 27th. But closest in daylight ~noon:13 @767,220Km moving 2.6'/min.
Paste these into your object editor:
2459940.666666667 = A.D. 2022-Dec-27 04:00:00.0000 TDB
EC= 4.188845495271784E-01 QR= 4.264283871532533E-01 IN= 8.397234543763176E+00
OM= 9.445591235794616E+01 W = 1.577558475912528E+02 Tp= 2460023.909607546870
N = 1.567936773396591E+00 MA= 2.294803318682904E+02 TA= 2.031761715000861E+02
A = 7.338101005682987E-01 AD= 1.041191813983344E+00 PR= 2.296010949600594E+02

Should work for your location in Ohio.

Here is a one degree wide FOV at 04cst on the 27th. The 6th mag star is HIP 66086 just 14' at pa288. Should make it crazy easy to locate the FOV.


The ephem position agrees with Horizons, etc.
It looks like the bright star is HR 5102 that's paired with HIP 66086 a 9.95 magnitude component.

Using MPC's elements for 2022 Nov 8 00:00 UT, ST4v predicts that 2010 XC15 will pass this system ~05:20 EST at 13.5 magnitude moving 136"/min. The earth distance will be 834.9k km.

That's very close to what you're getting.

Phil S.

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