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Close Approach of 2022 NF
Hi MP Hunters,

Here's another one! The newly discovered NEO 2022 NF is predicted to make a close approach on July 7 at 1400 ±0032 UT according to the CNEOS website. Close approach distance is only 0.00060 AU, H=28.4 and 'Rarity'=1.

Using orbital elements downloaded from the MPC on 2022 July 5, ST4v predicts that this NEO will reach a peak brightness of 15.4 magnitude on July 7 at 0800 EDT (1200 UT) when it will be 121.1k km distant moving through CrB at 13.4"/sec! At close approach of 92.2k km at 1000 EDT it will still be 16.1 magnitude moving through Ursa Minor at 25.0"/sec.

This one is a real screamer!!

Someone on the west coast of North America might have a shot at this one. Greg would have a shot on the morning of July 7 as well.

Good hunting,

Phil S.

I forgot to include the Interactive Atlas chart showing the predicted path of 2022 NF:     

This chart is for Mesa Redonda Observatory because Greg will have a better view if the weather cooperates.
This one is a very real screamer (26.3'/min and stays that speed for fully 7 minutes) but far too low and at from 15.4-16.1, too faint (poor phase). Closest approach for me comes at 9:07 CDT July 7th (87,739Km). Again, popped up on the daily fetch.
The orbital elements that I downloaded for 2022 NF altered some of the predictions. The CNEOS website now has the close approach occuring on July 7 at 1345 ±03 UT at a distance of 0.00059 AU, H=28.5, 'Rarity'=1.

Some of the predictions from ST4v have changed as well. Here's a revised IA chart showing the predicted path of 2022 NF on the morning of 2022 July 7 from Mesa Redonda Observatory:     

Unfortunately it didn't get any brighter  Wink, but it is moving even faster than initially predicted. At close approach it's moving through Ursa Minor at 25.2"/sec, although still in daylight  Sad !

Several more NEOs were added to the zoo, but none will be brighter than 17.7 magnitude when they pass by.

Phil S.
Since this guy is so fast and nearby, I thought I would experiment. Just grabbing the NEAs at Today's Epoch will not cut it. The only way to get a precise position of this very close fast mover is to import (copy/paste) an osculating element set using Horizons very near the time of observation. Otherwise I get positional errors of 19m54s in RA & 4°56'3" in DEC using those from Horizons vs todays epoch from my location at closest. It's moving near 1/2°/minute. With each step in time drastically altering its orbital elements. It appears that using the July 4 elements at Horizons and using specialty software, the close approach to my yard falls at 8:52CDT on July 7th at a distance of 87,374Km (0.00058404280872AU) with a speed of 1590"/min, magnitude 16.3, altitude 14°. I love to experiment. Just keep wanting one bright enough in a dark sky to eek out in my portable scope. Using ST4 to fetch those timely osculating elements matches those figures.

Both the MPC and Lowell are using elements for JD 2459800.5 (Aug 9 0:00UT) while those found at JPL are July 4.

That's a pretty large position error. Aug 9 00:00 UT is MPC's current standard epoch for their elements, but the epochs for the NEOs are calculated daily & available over a ±15 day interval. Unfortunately I don't know how to get ST4v to use the elements for Jul 7 00:00 UT until I download them tomorrow when it's too late to be of use.

The epoch used for today's revised path prediction was Jul 6 00:00 UT. The Object Info display says Jul 5, but ST4v reports that date as the 'Evening of', so the evening of Jul 5 includes Jul 6 00:00 UT. The only way to get elements at the time of the close approach would be to obtain elements from HORIZONS & edit ST4v's MP DB to use the new elements. That's what we did last summer.

Perhaps Greg will take a shot at it. He seems to be in a good location to view it.

Phil S.
More experimenting. Even though this small rock is below my mag limit, I decided to pass on the correct positions at 4CDT as it was 11° up. Again the best way is to use Horizons generated osculating elements edited into ST4. I chose 4am CDT.

This is the ephemeris generated by both Horizons Observer Table and SkyTools 4. The accuracy of the ST4 ephemeris held up for at least an hour using the 4am osculating elements.


Here is the IA plot for a 7 minute track where motion was ~1/2°:


Greg has given us all the tools we need to plot these crazy small, fast rocks from space.

Yes, the ST4v positions look great, as expected when using the same osculating elements. 

I downloaded the latest version of elements from MPC's NEAs at Today's Epoch again today, but didn't make a new plot to see how much the path has changed. Given the large errors that you report, the differences should be substantial between the positions predicted using the Jul 6 vs. the Jul 7 elements. Per the MPC website the NEAs Today data file was updated at 17:02 UT today.

Here is the revised path using the 2022 Jul 7 elements:     

There may not be sufficient resolution to detect the error in position at this scale. Maybe these elements don't have the effects of the close approach included yet since the epoch is for Jul 7 00:00 UT which is before the approach. Oh well, try again tomorrow.

Phil S.

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