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Observing (99942) Apophis in 2020

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#1 cbellh47

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Posted 21 January 2021 - 12:29 PM

Near Earth Asteroid (99942) Apophis is approaching Earth this year on

2021-Mar-06 01:15 at 0.11265113489653 au or 43.84 lunar distances (LD).

I observed it on December 26, 2020 from my observatory at H47 when it was near magnitude 19.

99942 Apophis (2004 MN4)
2020-Dec-26 11:33:45.000 UTC
JPL Horizons Ephemeris Data:
JD = 2459209.981770833
t - T = +108.9188 days from perihelion
RA 174.12157 Dec -12.6528
Delta = 0.249 au Earth distance
r = 1.035 au heliocentric distance
Elongation = 95.0 deg
Phase = 71.2 deg
PsAng = 295.3 deg antisolar direction
PsAMV = 242.2 deg -v direction
PlAng = +12.5 deg orbit plane angle
True Anomaly = 137.7 deg
Constellation: Crater  (Crt)
EclLon = 108.3372 deg
EclLat = -3.3203 deg

Apophis  has brightened to near magnitude 17.5 according to today's ephemeris.
Apophis  is currently  located in the sky constellation of Crater.

I read today that the OSIRIS-REx mission is considering (99942) Apophis as a follow on target . The mission team plans to propose an extended mission to NASA in the summer of 2022.

Goldstone Radar is planning to observe it in the coming weeks of January 2021.

(99942) Apophis brightened and was recovered by several NEO sky surveys in December as part of a Planetary Defense exercise which is now complete. The IAWN Apophis exercise continues.

Attached Thumbnails

  • (99942) Apophis-2020Dec26.PNG

Edited by cbellh47, 21 January 2021 - 12:31 PM.

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#2 Stellar1

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Posted 21 January 2021 - 01:15 PM

Amazing, i bet locating such a minuscule target couldn't be easy, how small is this asteroid? 


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#3 cbellh47

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Posted 21 January 2021 - 01:37 PM

(99942) Apophis has a diameter of 340  meters derived by  Brozovic et al. (2018) from radar observations in 2012-2013.

At its current earth distance it appears point like with a radial profile like a star.

Image was made using a12 inch Meade 200LX-GPS Schmidt-Cassegrain telescope mounted a super heavy duty tripod and equatorial wedge, precisely polar aligned,  plus F/6 focal reducer plus SBIG  ST-8XM CCD and CFW with B,V,R,I filters.

Equipment image posted on wordpress site
https://cbellh47.com/observatory/

The image is a screen grab of the Astrometrica object verification dialog.
Astrometrica is a program for astrometry measurements or precise position measurement.

Astrometry was submitted to the Minor Planet Center.


 



#4 Stellar1

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Posted 21 January 2021 - 02:01 PM

(99942) Apophis has a diameter of 340  meters derived by  Brozovic et al. (2018) from radar observations in 2012-2013.

At its current earth distance it appears point like with a radial profile like a star.

Image was made using a12 inch Meade 200LX-GPS Schmidt-Cassegrain telescope mounted a super heavy duty tripod and equatorial wedge, precisely polar aligned,  plus F/6 focal reducer plus SBIG  ST-8XM CCD and CFW with B,V,R,I filters.

Equipment image posted on wordpress site
https://cbellh47.com/observatory/

The image is a screen grab of the Astrometrica object verification dialog.
Astrometrica is a program for astrometry measurements or precise position measurement.

Astrometry was submitted to the Minor Planet Center.


 

This is all very interesting, I was not aware such a small target could be imaged with the average scope amateurs posses.

Your scope setup is impressive!


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#5 cbellh47

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Posted 21 January 2021 - 04:50 PM

(99942) Apophis sky positions and path from January 21, 2021 through March 22, 2021. Apophis begins to move westward from constellation of Crater at the end of January 2021 passing into Hydra in mid- February 2021, then cutting across southwest corner of Sextans, then reentering Hydra in March 2021.
Position dots are plotted at one day increments. Spacing between dots increases as sky motion increases which increases as the distance to Apophis decreases.
At closest approach on March 6, 2021, Apophis sky motion will reach 3.37 arcsec/min.

https://www.flickr.c...57717980827873/


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#6 Stellar1

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Posted 21 January 2021 - 05:13 PM

(99942) Apophis sky positions and path from January 21, 2021 through March 22, 2021. Apophis begins to move westward from constellation of Crater at the end of January 2021 passing into Hydra in mid- February 2021, then cutting across southwest corner of Sextans, then reentering Hydra in March 2021.
Position dots are plotted at one day increments. Spacing between dots increases as sky motion increases which increases as the distance to Apophis decreases.
At closest approach on March 6, 2021, Apophis sky motion will reach 3.37 arcsec/min.

https://www.flickr.c...57717980827873/

I gather that at 18.8 mag i have no chance in heck of spotting this with my 115mm refractor.


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#7 cbellh47

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Posted 21 January 2021 - 07:28 PM

If you can get your telescope to guide and using a sensitive CCD camera and stacking sufficient number of frames, a equatorially mounted refractor that large should be able to image something that faint. 

I stacked lots of images for my observations in December.


Apophis has brightened by at least one magnitude since I observed it.
If you have never tried a moving object before, it would be advisable to try a much brighter main belt asteroid and work your way up to fainter ones.



 


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#8 Stellar1

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Posted 21 January 2021 - 07:52 PM

If you can get your telescope to guide and using a sensitive CCD camera and stacking sufficient number of frames, a equatorially mounted refractor that large should be able to image something that faint. 

I stacked lots of images for my observations in December.


Apophis has brightened by at least one magnitude since I observed it.
If you have never tried a moving object before, it would be advisable to try a much brighter main belt asteroid and work your way up to fainter ones.



 

I am inspired, i will make this a challenge, soon as spring comes (winter in Canada is no joke) i'll give it the old college try!



#9 John Rogers

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Posted 22 January 2021 - 02:30 PM

Thanks for the report.  If you are not aware of it, I recommend checking out Tycho Tracker, developed by Daniel Parrott.  It is a game changer for NEO observing.

 

https://www.cloudyni...ycho/?p=9656958


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#10 RazvanUnderStars

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Posted 23 January 2021 - 12:39 AM

Tycho is excellent, indeed. Highly recommended to watch the videos on its YouTube channel to see what it can do.

 

 

Thanks for the report.  If you are not aware of it, I recommend checking out Tycho Tracker, developed by Daniel Parrott.  It is a game changer for NEO observing.

 

https://www.cloudyni...ycho/?p=9656958



#11 cbellh47

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Posted 23 January 2021 - 12:17 PM

Thanks for comments, suggestions, discussion, and recommendations. Always welcome.

I am hoping others will try to followup on this very important hazardous asteroid approaching earth this year and perhaps draw attention to it.  The (99942) Apophis Observing Campaign started in earnest in recent months with Vishnu Reddy as lead investigator. Look for IAWN on the Minor Planet Center website. Dave Tholen used some rather large telescopes via Univ of Hawaii to measure the Yarkovski effect on Apophis. He was one of the discoverers of this object in 2004. D. Farnocchia at the Jet Propulsion Laboratory, Pasadena, CA is working with him.
 

Tycho is a very fine program and remember seeing David Parrott's posts on social media and have seen countless screen captures of faint objects using Tycho. I hope to see more posts on Cloudy Nights by those recommending Tycho and finding new things.

I have been quite happy using Track and Stack with Astrometrica for many years now, since about 2005 for reporting astrometric observations to the Minor Planet Center. It gave me the ability to go deeper for fainter targets without have to get a larger telescope.

I mainly observe comets from H47 that are already known and sometimes do followup on objects on the NEOCP or PCCP.

Usually my observing targets are very faint and I always have plenty of them to fill my morning observing times when I finally get clear skies. I report every object I find moving in the field. 

Automated surveys find almost everything with several more coming on line in 2021 at southern latitudes.   I read all the MPECs and see that the apertures they are using for discovery. I am way outclassed by all that. 

Good morning.
Charles

 


Edited by cbellh47, 23 January 2021 - 12:18 PM.


#12 cbellh47

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Posted 05 February 2021 - 07:53 PM

(99942) Apophis orbit and Earth impact risk have been updated to include the latest Yarkovski effect measurements.

The Yarkovski effect manifests itself in the motion of the asteroid as an additional tangential acceleration. This can be included in the orbit determination process as an additional parameter of the fit, usually labeled A2.
 

In the JPL Small Body database
A2 [EST]  -2.882874824076915E-14  +/- 3.888E-15 :  au/d^2

https://ssd.jpl.nasa...log=0;cad=1#cad

CNEOS Sentry: Earth Impact Monitoring page now shows analysis based on 4716 observations spanning (2004-03-15.12629 to 2021-01-19.10955)

with new values for the 2056-04-13.10 close encounter event and very small probability of impact (3.0e-7)

CNEOS is NASA's center for computing asteroid and comet orbits and their odds of Earth impact.

https://cneos.jpl.na...tml#?des=99942


 

The NEO Coordination Centre news page includes an announcement "Impact monitoring for Apophis computed including the Yarkovsky effect" posted 22 January 2021.
http://neo.ssa.esa.int/
 




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