Date   

2016 PG215 vs P/2017 S9 (PANSTARRS)

alessandro odasso
 

After importing these two objects in Tony Dunn's orbit simulator, I run a backward simulation, it seems that these two objects reached their minimum distance (about 1.3 million km with a relative velocity about 0.2 km/s) around year 1722

I repeated the simulation with Mercury6 with 100 clones for each object:
  1. looking at the relative distance, the "best" two clones reached a minimum distance about 64000 km around year 1835 with a relative velocity around 0.2 km/s
  2. looking at the relative velocity, the "best" two clones got it at about 1 m/s at a distance about 8million km around year 1658

Clearly, due to the orbit uncertainties, we have a high variance in distance, speed and time, but I wonder whether we can reasonably speculate that the asteroid 2016 PG215 is a fragment of comet P/2017 S9 (PANSTARRS) or whether this is just something occurring by chance.

See plots:

Best wishes,
Alessandro Odasso


Re: (CORRECTION) A very minor planet (ESA's Solar Observatory flyby)

 

Very cool links, Patrick!  --John in New Mexico.


On Saturday, November 27, 2021, Wiggins Patrick <4099wiggins@...> wrote:
Sorry, that was the wrong link.  Here’s the correct one:

https://www.facebook.com/1407672426/videos/497107024766208/

patrick
718


> On Nov 27, 2021, at 00:50, Wiggins Patrick via groups.io <4099wiggins=gmail.com@groups.io> wrote:
>
> It was moving fast.  Hard to keep up with.
>
> https://www.facebook.com/1407672426/videos/2494834823982900
>
> patrick
> 718
>
>
>
>
>







(CORRECTION) A very minor planet (ESA's Solar Observatory flyby)

Wiggins Patrick
 

Sorry, that was the wrong link. Here’s the correct one:

https://www.facebook.com/1407672426/videos/497107024766208/

patrick
718

On Nov 27, 2021, at 00:50, Wiggins Patrick via groups.io <4099wiggins=gmail.com@groups.io> wrote:

It was moving fast. Hard to keep up with.

https://www.facebook.com/1407672426/videos/2494834823982900

patrick
718





A very minor planet (ESA's Solar Observatory flyby)

Wiggins Patrick
 

It was moving fast. Hard to keep up with.

https://www.facebook.com/1407672426/videos/2494834823982900

patrick
718


Re: Planet astrometry file ?

Roger Sinnott
 

Planetary astrometry before 1900, while not as accurate as that since, wasn't all that bad. It amazes me that Leverrier could derive a fairly accurate value for the then-mysterious advance in Mercury's perihelion using timings of transits of Mercury from 1697 through 1848.  Simon Newcomb, with a few more transits, did even better:

    38.3 arcsec/century (Leverrier, 1859)
    43.4 arcsec/century (Newcomb, 1895)
    43.0 arcsec/century (general relativity)

Roger S.


Re: Automatic download of NEOCp ephemerides possible?

Bernd Häusler
 

Hi Jost,

go to the NEOCP in the browser with mouse right click on "check the side (examine)" to see the HTML source text.
Then search for the following code:

<form method="POST" action="https://cgi.minorplanetcenter.net/cgi-bin/confirmeph2.cgi">

If you find such a code on any page, you can immediately see that the "get" button, in our case the "Get Ephemerides" button, offers a so-called CGI query.
Now you just look for the parameter list in the source text and you get the required parameters in the CGI request.



<input name="mb" maxlength=4 size=4 value="-30"> to
<input name="mf" maxlength=4 size=4 value="30">, with Decl. between
<input name="dl" maxlength=5 size=5 value="-90">&#176; and
<input name="du" maxlength=5 size=5 value="+90">&#176;, with an
NEO desirability score of
<input name="nl" maxlength=3 size=3 value="0">&#37; to
<input name="nu" maxlength=3 size=3 value="100">&#37;
<input type="hidden" name="sort" value="d">
<p><input type="radio" name="W" VALUE="j" CHECKED>or just the objects selected below:



<input name> supplies the parameter name for the CGI query.
The rest is syntax

Only programmers Latin 😊

Best and good luck for your automated observation

Bernhard

Thank you Bernhard,
that works and made my night preparations (and changes in the night) more easy.
So my scripts for ACP can be changed any time in the night by program and I can sleep...
I'll evaluate the parameters in detail.
Is this an "official" use (documentation?)?
Jost


Re: Automatic download of NEOCp ephemerides possible?

Jost Jahn
 

Thank you Bernhard,
that works and made my night preparations (and changes in the night) more easy.
So my scripts for ACP can be changed any time in the night by program and I can sleep...
I'll evaluate the parameters in detail.
Is this an "official" use (documentation?)?
Jost


Re: Planet astrometry file ?

Marshall Eubanks
 

On 2021-11-25 11:18, Brian Skiff wrote:
On Nov 25, 2021, at 1:50 AM, "Piotr A. Dybczyński <piotr@dybczynski.pl> wrote:
Hi Adrien,
the problem with old cometary astrometry data is that they were published as
differential astrometry, i.e. comet minus star. Sometimes star positions are
quoted from some catalogue, sometimes only a catalogue name is given. The
similar problem is with the place of observations and the time system used.
Both are individual and change with time.
This is not a new problem, since the circumstance obviously beset
the original observers and orbit computors at the time (needing to
convert differential micrometry to some absolute system, and dealing
with various clock-time issues). There were long lists published of
improved coordinates for ‘faint’ stars on whatever the standard system
A lot of these publications were/are in observatory annual reports, which you could maybe find at the US Naval Observatory or the Paris Observatory or some other major astronomical library in paper form.

Until about 1960 most ephemeris work was done by hand with selected sets of data, for example many national observatories used mostly or entirely the data collected by their own telescopes and recorded those data using their own time systems.

In the 1960s, the MIT (later CFA) group under Irwin Shapiro (which I worked for later on) and the JPL DPODP group both had to go through these old records and make what sense of them they could in order to make the first good dynamical epherides. The goal was to make use of spacecraft observations, and get spacecraft to desired targets.

The individual star catalogs most observatories used (for the differential transit type measurements) and the individual time systems meant that going into the past, and in particular before the photographic era, was difficult. However, there were long stretches of data from certain observatories (e.g., the national observatories) and those could be reanalyzed with a more modern system. So, those formed the basis for these first dynamical ephemerides, and are still used today.

A lot of the old data have various forms of systematic errors. If you look at the Planet X searches from the 1970's (which did use some of the old optical data), it seems like many of old outer planet data has serious rate type errors that I suspect were zonal errors in the underlying star catalogs. It can be very hard to figure out what's really going on with very old data from limited observatory reports.

Irwin eventually concluded that the optical data was simply not very good, and stopped using it for Mercury, Venus and Mars in favor of radar ranging data even before the spacecraft data became available.

Now, all of these data could now be put on the Gaia catalog and a decent ephemeris time, and you could probably get arc second level measurements out of even pretty old data, but the question arises, would it be worth the effort?

Note that old optical data, going back to Babylonian eclipse timings in ~700 BC, are crucial to determining Earth rotation in the period before 1970, and there has been serious effort to find these old data and make use of them. I think that these are mostly lunar eclipse data.

Conversely, the Lunar dynamical ephemeris is 100% based on LLR data today, even though there are of course centuries of lunar data available.

I hope everyone has a good Thanksgiving.

Regards
Marshall


was at the time (and not in the early zone catalogues), and various
catalogues that collected all this. So the star-names/IDs and ‘pretty
good’ coordinates ought to exist in print somewhere. A big nuisance
to trace things back, you bet, but imagine trying to do it by hand
with log/trig tables and a pepper-grinder calculator, if such you had!
\Brian


Re: Automatic download of NEOCp ephemerides possible?

Bernd Häusler
 

Hi Jost,

Yes indeed. Neo Planner automatically loads the ephemeris from the NEOCP for any observatory. Load
the file with the MPC's web service into a file with the following URL:

sUrl = "https://cgi.minorplanetcenter.net/cgi-bin/confirmeph2.cgi?W=a&mb=-30&mf=" & mf &
"&dl=" & dl & "&du=" & du & "&nl=" & nl & "&nu=" & nu &
"&sort=d&Parallax=1&obscode=" & observatory & "&int=" & intx & "&start=" & startx &
"&raty=a&mot=m&dmot=p&out=f&sun=s"

and replace the variables with your own parameters.

Example:
https://cgi.minorplanetcenter.net/cgi-bin/confirmeph2.cgi?W=a&mb=-30&mf=22.0&dl=-15&du=+75&nl=000&nu
=100&sort=d&Parallax=1&obscode=K87&int=1&start=00&raty=a&mot=m&dmot=p&out=f&sun=s

Best, Bernhard, K87

https://www.k87dettelbachvineyardobservatory.bayern/NeoPlanner.htm


Re: DART and booster animated GIF

Nick James
 

The attached Astrometry got removed but you can find it here along with an animation showing the spacecraft and Falcon 9 upper stage.

https://nickdjames.com/Spacecraft/DART/

Nick.

On 25/11/2021 17:51, Nick James wrote:
Hi Patrick,
I managed to get the spacecraft and booster tonight in bright twilight just before the clouds rolled in here in the southeast of England. Astrometry attached in case it is useful.
Nick.
On 25/11/2021 03:47, Wiggins Patrick wrote:
I shot and stitched together several images of the spacecraft and booster and put the resultant animated GIF on my Facebook page.

Interesting to watch how the booster is constantly changing brightness as it tumbles.

I set it to public so I *think* everyone can see it.

https://www.facebook.com/patrick.wiggins.71

patrick
718




Re: DART and booster animated GIF

Nick James
 

Hi Patrick,

I managed to get the spacecraft and booster tonight in bright twilight just before the clouds rolled in here in the southeast of England. Astrometry attached in case it is useful.

Nick.

On 25/11/2021 03:47, Wiggins Patrick wrote:
I shot and stitched together several images of the spacecraft and booster and put the resultant animated GIF on my Facebook page.
Interesting to watch how the booster is constantly changing brightness as it tumbles.
I set it to public so I *think* everyone can see it.
https://www.facebook.com/patrick.wiggins.71
patrick
718


Automatic download of NEOCp ephemerides possible?

Jost Jahn
 

Hi,
I want to include the ephemerides of all asteroid up to 22th magnitudes using the NEOCP page https://minorplanetcenter.net/iau/NEO/toconfirm_tabular.html into my own programs.
At moment I copy the page to a local file, changing the parameters with a program, but must click on the "get ephemerides" button.
I tried it with curl, but find not the right way to use it with -d option.
Does anyone has automated the download of the ephemerides?
Jost


Re: Planet astrometry file ?

Brian Skiff
 

On Nov 25, 2021, at 1:50 AM, "Piotr A. Dybczyński <piotr@dybczynski.pl> wrote:

Hi Adrien,

the problem with old cometary astrometry data is that they were published as
differential astrometry, i.e. comet minus star. Sometimes star positions are
quoted from some catalogue, sometimes only a catalogue name is given. The
similar problem is with the place of observations and the time system used.
Both are individual and change with time.


This is not a new problem, since the circumstance obviously beset the original observers and orbit computors at the time (needing to convert differential micrometry to some absolute system, and dealing with various clock-time issues). There were long lists published of improved coordinates for ‘faint’ stars on whatever the standard system was at the time (and not in the early zone catalogues), and various catalogues that collected all this. So the star-names/IDs and ‘pretty good’ coordinates ought to exist in print somewhere. A big nuisance to trace things back, you bet, but imagine trying to do it by hand with log/trig tables and a pepper-grinder calculator, if such you had!


\Brian


Re: Planet astrometry file ?

"Piotr A. Dybczyński
 

Hi Adrien,

the problem with old cometary astrometry data is that they were published as
differential astrometry, i.e. comet minus star. Sometimes star positions are
quoted from some catalogue, sometimes only a catalogue name is given. The
similar problem is with the place of observations and the time system used.
Both are individual and change with time.

If you are interested in details see for example my paper on C/1890 F1 Brooks:

https://ui.adsabs.harvard.edu/abs/2016MNRAS.460.2905K/abstract

Cheers,
Piotr
--
/**************************************************************************
Prof UAM dr hab. Piotr A. Dybczyński
homepage: https://apollo.astro.amu.edu.pl/PAD e-mail: dybol@amu.edu.pl
Astronomical Observatory Institute, http://www.astro.amu.edu.pl
Adam Mickiewicz University, Poznań, Poland https://amu.edu.pl
********************************************************************PAD***/


W liście nadanym Wed, 24 Nov 2021 22:04:25 +0100 "Adrien Coffinet"
<adrien.coffinet2@gmail.com> pisze:

Am I wrong that, for (periodic) comets too, the MPC doesn't register data
before the 19th century? (eg 1P only from 1835, 2P from 1852...)

And why, even for comets discovered during that century, aren't there all
the observations back to the discovery? (eg 4P discovered in 1843, but data
listed only from 1865; 6P discovered in 1851, but data from 1870...)

Of course, comets have the additional complication of non-grav (is it why
JPL uses only the last orbit, or a few last orbits, even for some of the
oldest-known comets?), but can't these older observations be used to
actually constrain these non-grav?


Re: Could newly-discovered 2020 XL5 be an Earth Trojan?

andrew_j_walker@...
 

Following this post I saw Sam Deen has submitted some observations from 2018, great work!
They are in the E2021-W43 DOU.

Andrew


On Wed, Nov 24, 2021 at 10:53 PM, <andrew_j_walker@...> wrote:
I spotted the other day a new MPEC for this object with its recovery in September and November

https://www.minorplanetcenter.net/mpec/K21/K21VP0.html

There's also a very interesting preprint looking at its dynamics using data from 2020 and the September observations

https://arxiv.org/abs/2111.05058

Andrew


Re: Could newly-discovered 2020 XL5 be an Earth Trojan?

andrew_j_walker@...
 

I spotted the other day a new MPEC for this object with its recovery in September and November

https://www.minorplanetcenter.net/mpec/K21/K21VP0.html

There's also a very interesting preprint looking at its dynamics using data from 2020 and the September observations

https://arxiv.org/abs/2111.05058

Andrew


On Tue, Feb 2, 2021 at 02:34 PM, tony873004 wrote:
Here's an animation showing why Venus can not destabilize 2020 XL5's Trojan configuration at the moment.
http://orbitsimulator.com/BA/2020_XL5_Venus_Plane.gif  
The simulation uses JPL Horizons nominal position and velocity vectors as a starting point.
The bright yellow is where the asteroid is above the plane of Venus' orbit, and the dark yellow is below, with the transitions showing the ascending and descending nodes.
When the asteroid is at Venus' distance from the Sun, it currently passes too high above Venus, or too low. But as the nodes precess over the centuries, and get close to Venus (lowering its MOID with Venus), Venus has a large influence on the asteroid's orbit, changing the shape of trojan orbit, ultimately sending it  over the L3.
 
 

On Thu, Jan 28, 2021 at 11:17 PM Wiggins Patrick <4099wiggins@...> wrote:
Pardon the pretty much off topic reply but you can tell I’m old since “XL5” reminded me of this from when I was a wee one:
https://en.wikipedia.org/wiki/Fireball_XL5

patrick  :)
718

> On 26 Jan 2021, at 19:18, tony873004 <tony@...> wrote:
>
> 2020 XL5 's nominal trajectory from JPL Horizons shows it librating about Earth's L4 point.
> http://orbitsimulator.com/BA/2020_XL5_c.gif
>
> 100/100 clones generated with FindOrb are doing the same.
> http://orbitsimulator.com/BA/2020_XL5.JPG
>







DART and booster animated GIF

Wiggins Patrick
 

I shot and stitched together several images of the spacecraft and booster and put the resultant animated GIF on my Facebook page.

Interesting to watch how the booster is constantly changing brightness as it tumbles.

I set it to public so I *think* everyone can see it.

https://www.facebook.com/patrick.wiggins.71

patrick
718


Re: P/2005 T2 (Christensen) versus 2020 OV62

Adrien Coffinet
 

Hi all,

MPEC W47 has just made official that P/2005 T2 = P/2012 V5 = P/2020 OV62 (Christensen).

Adrien 

Le mar. 23 nov. 2021 08:07, Sam Deen <planetaryscience@...> a écrit :
The elongation seems quite consistent with time - about 0.25 arcseconds separated, so seems compatible with the expected hill sphere. The observations as you can see are pretty sparse though, so I'll reserve any other speculation on what the elongation is without more detailed observation, probably at its next apparition.

~Sam
On Monday, November 22, 2021, 06:01:35 PM PST, Adrien Coffinet <adrien.coffinet2@...> wrote:


Great, Sam!

Have you tried to make a plot of asteroid elongation vs. time, and/or magnitude vs. time? If it is really a binary, we should see variations.

Also, do you have an estimate of the elongation? i.e. how large the system would be?

Assuming an albedo of 0.05~0.5, H=17.5 <=> diameter 0.6~1.9 km, so assuming a density of (1~3)e3 kg/m3, it makes a mass of (0.1~11)e12 kg (assuming a roughly spherical shape for the calculation, probably not the worst assumption given the wide range we already have). With a perihelion at 2.2 au, it makes a Hill sphere radius of only 84~400 km, that is only 0.1~0.5 arcsecond when the object is closest to the Earth, at ~1.2 au.

Is it compatible?

Le mar. 23 nov. 2021 à 02:53, alessandro odasso <alessandro_odasso@...> a écrit :
Thanks Sam, great work! 

Is it possibile to see and compare it  with the original 2005 images?

Cheers,
Alessandro

Il 23 Nov 2021 00:48, Sam Deen <planetaryscience@...> ha scritto:
Hi all,

I've recovered P/2005 T2 in 2012/2013 and linked it up to (P/)2020 OV62:

    PK05T020 ZC2012 08 03.35680 19 02 00.45 -14 04 51.4          20.5 i      F51
    PK05T020 ZC2012 08 08.34915 19 00 06.39 -13 56 43.4          21.8 g      F51
    PK05T020 ZC2012 08 08.35943 19 00 06.16 -13 56 42.4                      F51
    PK05T020 ZC2012 08 08.37033 19 00 05.94 -13 56 41.7          20.7 r      F51
    PK05T020 ZC2012 08 08.38047 19 00 05.71 -13 56 40.6                      F51
    PK05T020  C2013 10 04.56396804 34 26.46 +26 21 57.7          23.4 i      568
    PK05T020  C2013 10 04.56648004 34 26.44 +26 21 57.7                      568
    PK05T020  C2013 10 04.56773404 34 26.44 +26 21 57.7                      568
    PK05T020  C2013 10 04.56900004 34 26.44 +26 21 57.6          23.3 i      568
    PK05T020  C2019 06 07.14674814 44 24.25 -21 13 44.8          22.6 g      W84
    PK05T020  C2019 06 23.10796914 38 24.10 -19 55 21.9          22.1 r      W84

   Perihelion 2020 Apr 5.281591 +/- 0.000649 TT =  6:45:29 (JD 2458944.781591)
Epoch 2020 Oct 23.0 TT = JDT 2459145.5   Ju: 0.4403           Find_Orb
M  26.24190247 +/- 0.00008          (J2000 ecliptic)
n   0.13073988 +/- 7.4e-9           Peri.   58.85646 +/- 0.00041
a   3.84471343 +/- 1.45e-7          Node   260.15412 +/- 0.00036
e   0.4159749 +/- 2.78e-7           Incl.    8.29133 +/- 0.000031
P   7.54           M(N) 15.4    K  10.0     U  0.7  
q 2.24540895 +/- 1.1e-6    Q 5.44401792 +/- 1.03e-6
From 118 observations 2005 Oct. 7-2020 Oct. 23; mean residual 0".81

There was no clear sign of a tail or any coma whatsoever in any of the images. Here's a stack of the 2013 images, which I'm pretty sure are looking at the bare nucleus:


It seems consistently slightly elongated E-W in 2013 and 2019 images, and I'm pretty sure it's not due to comet activity as there's little sign of haziness otherwise. Possibly a binary object?

~Sam


On Monday, November 22, 2021, 10:46:39 AM PST, alessandro odasso <alessandro_odasso@...> wrote:


Thanks Adrien!

Cheers,
Alessandro



From: Adrien Coffinet <adrien.coffinet2@...>
Sent: Monday, November 22, 2021 7:11 PM
To: alessandro odasso <alessandro_odasso@...>
Cc: MPML Groups.io <mpml@groups.io>
Subject: Re: {MPML} P/2005 T2 (Christensen) versus 2020 OV62
 
Hi,

Given that its orbital period is essentially a half-integer number of years (7.5 years), recovering this object after 2 orbits (and missing it in 2012) sounds plausible.

Note also that, according to JPL's SBDB, the comet's nucleus absolute magnitude (M2) is 17.5 +/- 0.4, i.e. the same as the absolute magnitude (H) of 2020 OV62.

Adrien


Le lun. 22 nov. 2021 17:25, alessandro odasso <alessandro_odasso@...> a écrit :
Not clear to me if this is a known case.

I used Find_Orb to get the orbital parameters for comet P/2005 T2 (Christensen)
I got the orbit even though 12 observations had to be discarded.

After that, I added asteroid 2020 OV62, and apparently no link was possible (mean_redisual 224")

What is strange is that when I turned on all perturbers, Find_Orb got essentially the same orbit without discarding the 2020 observations with a mean residual = 0.59
(I also tried to invert the calculation by adding first the asteroid and after that the comet ... no obs were discarded and the linkage had a mean resisual = 0.85)

Do you also think that asteroid 2020 OV62 is actually comet P/2005 T2 (Christensen) or maybe a fragment of it ?

Best wishes,
Alessandro Odasso



Re: Planet astrometry file ?

David Tholen
 

Of course, comets have the additional complication of non-grav (is it why JPL uses only the last orbit, or a few last orbits, even for some of the oldest-known comets?), but can't these older observations be used to actually constrain these non-grav?
Perhaps, in some well-behaved cases. But active areas on comets can come
and go, so the non-gravs can change with time. As such, trying to fit all
the observations of a comet could actually lead to more poorly constrained
non-gravs, reflecting their variability.


Re: Planet astrometry file ?

Adrien Coffinet
 

Am I wrong that, for (periodic) comets too, the MPC doesn't register data before the 19th century? (eg 1P only from 1835, 2P from 1852...)

And why, even for comets discovered during that century, aren't there all the observations back to the discovery? (eg 4P discovered in 1843, but data listed only from 1865; 6P discovered in 1851, but data from 1870...)

Of course, comets have the additional complication of non-grav (is it why JPL uses only the last orbit, or a few last orbits, even for some of the oldest-known comets?), but can't these older observations be used to actually constrain these non-grav?


Le mer. 24 nov. 2021 21:33, Brian Skiff <bas@...> a écrit :
On Nov 24, 2021, at 12:47 PM, tme@... wrote:

What Myles Standish (who led the JPL ephemeris effort for years) used to do was to use an ephemeris derived from the "modern" data to predict (retrodict) residuals for these earlier data sets. Based on that he felt that there was just no need for the pre-photographic data, not even the Galileo data on Neptune (he went to Italy to look a G.G.'s original lab notes on that.)

     I understand this, and recall the interest in Galileo's observations of Neptune published by Stillman Drake and Charlie Kowal in “Scientific American” back in the day:

https://ui.adsabs.harvard.edu/abs/1980SciAm.243f..52D/abstract

But I would be more interested in what was observed/measured, and how it was done, even though one can now predict coordinates etc better than what was measured at the time.
     It has been only recently that the old stuff has become irrelevant for orbit-determination etc, so somebody _must_ have collected all the old stuff as things went along, probably keying it in at some point by the late 20th Century, to evaluate it as things progressed.  Did all such files (and biblio) simply get deleted?


\Brian






1 - 20 of 36969