Rosetta Comet chaser closing in- *** GLP has discovered a new asteroid - New picture page 7, no name yet, share your thoughts ***

And another point, I saw another image from a fellow scientist who did something else newsworthy I can't talk about yet. In any case, his image overlapped mine in the same area where I think I detected Rosetta. There was no star there in his image, and his went a bit deeper than mine. Something was there which is not there now, the only question is whether it was really Rosetta or something else.

That sounds promising. I had a look at the ESA SPICE Kernel that was generated on the 21st, presumably to take into account braking data and updated postion information. It turns out that file and all the other Rosetta ones have been mirrored over to JPL. So I have run WebGeocalc and manually loaded the most recent Rosetta kernels. In the state vector calculation page select manual from kernel selection and load the following kernels

ROSETTA/kernels/lsk/NAIF0010.TLS
ROSETTA/kernels/sclk/ROS_140501_STEP.TSC
ROSETTA/kernels/spk/RORB_DV_006_01_______00014.BSP
generic_kernels/spk/planets/de430.bsp

The last one has Earth ephemeris, I haven't checked if it is the best version yet.

Running the calculation again I get

Calculation Inputs

Calculation type = State Vector
Target = ROSETTA
Observer = EARTH
Reference frame = J2000
Light propagation = To observer
Light-time algorithm = Converged Newtonian
Stellar aberration = Corrected for stellar aberration
Time system = UTC
Time format = Calendar date and time
Input time = 2014 MAY 21 17:30:00.000
State representation = Right ascension, declination, range


State Vector Results

UTC calendar date Right Ascension (deg) Declination (deg) Range (km) d Right Ascension/dt (deg/s) d Declination/dt (deg/s) d Range/dt (km/s) Speed (km/s) Time at Target Light Time (s)
2014-05-21 17:30:00.000000 UTC 298.00206827 -27.83081641 498072102.68513110 -5.84643451E-07 -4.92783919E-07 -29.70016708 30.34222382 2014-05-21 17:02:18.610297 UTC 1661.38970276

This time using light-time adjustment. You said you want topocentric coordinates. They have the following coordinate systems

[link to wgc.jpl.nasa.gov:8080]

So I guess one of these is more helpful for you. Anyway even if you don't use it this time I am sure it will become a favourite tool of yours.

[link to wgc.jpl.nasa.gov:8080]



Yes I think I have heard of this mysterious planet, there is a website called zeta something all about it ;)

K

Now this makes me wet. It's like astro porn lol

Congrats Astro! No wonder you have so much haters in here. People will forgive you everything, but success of any kind.

OK I have just checked the file

generic_kernels/spk/planets/de430.bsp

and it had planetary data including the Earth up to JAN 25 2650 so its all right to use for the next 636 years.

K

Hmm, that yields a result that is still close but a few arcseconds farther from my detected location than what JPL Horizons yielded... I can do the conversion to topocentric coordinates myself, which I did. It doesn't much matter given the distance involved.

Well I am winging it a bit here as a SPICE novice so I am quite possibly doing something wrong. Webgeocalc can produce time series plots and charts, would that provide any additional help to you?

K

Nah, the numbers are what I need. It's possible that stellar aberration is the problem child above; my measurements are with respect to the stars immediately surrounding it, so stellar aberration is a constant anyway and should not be factored into the calculation.

I checked it with the previous Rosetta kernel produced three days previously and that produced identical results. Here is the calculation again without stellar aberration compensation.

State Vector Results


Calculation Inputs

Calculation type = State Vector
Target = ROSETTA
Observer = EARTH
Reference frame = J2000
Light propagation = To observer
Light-time algorithm = Converged Newtonian
Time system = UTC
Time format = Calendar date and time
Input time = 2014 MAY 21 17:30:00.000
State representation = Right ascension, declination, range


State Vector Results

UTC calendar date Right Ascension (deg) Declination (deg) Range (km) d Right Ascension/dt (deg/s) d Declination/dt (deg/s) d Range/dt (km/s) Speed (km/s) Time at Target Light Time (s)
2014-05-21 17:30:00.000000 UTC 297.99859929 -27.83195630 498072102.68513113 -5.85730835E-07 -4.92904907E-07 -29.70016708 30.34360464 2014-05-21 17:02:18.610297 UTC 1661.38970276


Kernels Used

ROSETTA/kernels/lsk/NAIF0010.TLS
ROSETTA/kernels/sclk/ROS_140501_STEP.TSC
generic_kernels/spk/planets/de430.bsp
ROSETTA/kernels/spk/RORB_DV_006_01_______00014.BSP

K

Alright, I don't have time to recrunch the numbers to topocentric again, but that is about the same as what JPL showed. I just wish I knew how accurate that actually was. It's strange, it's very close to my detected location, but it's just a few arcseconds off. There are no stars at the detected coordinates, it didn't appear the next day I imaged the detected coordinates, a couple of other asteroids did appear the next day but they're both known asteroids and neither was anywhere close to the detected coordinates the previous day when Rosetta was performing its burn. There are only two possibilities I can think of that make any logical sense; either the ephemeris we're generating or my astrometry results are just a few arcseconds off for some reason I can't think of right now, or I accidentally discovered a new minor planet (asteroid or comet) that happened to coincidentally be right next to Rosetta in the sky from the perspective of earth.

I think tantalising is the word. Here is some time series in csv format. Are any of these closer to your point?

"State Vector Results"
"Calculation Inputs"
"Calculation type","State Vector"
"Target","ROSETTA"
"Observer","EARTH"
"Reference frame","J2000"
"Light propagation","To observer"
"Light-time algorithm","Converged Newtonian"
"Time system","UTC"
"Time format","Calendar date and time"
"State representation","Right ascension, declination, range"
"State Vector Results"
"UTC calendar date","Right Ascension (deg)","Declination (deg)","Range (km)","d Right Ascension/dt (deg/s)","d Declination/dt (deg/s)","d Range/dt (km/s)","Speed (km/s)","Time at Target","Light Time (s)"
"2014-05-21 16:30:00.000000 UTC",298.00071084,-27.83018351,498178997.60103387,-5.87350529​E-07,-4.91977920E-07,-29.68590079,30.33063940,"2014-05-21 16:02:18.253734 UTC",1661.74626582
"2014-05-21 17:00:00.000000 UTC",297.99965433,-27.83106949,498125556.56282880,-5.86541566​E-07,-4.92441269E-07,-29.69303133,30.33711918,"2014-05-21 16:32:18.431994 UTC",1661.56800570
"2014-05-21 17:30:00.000000 UTC",297.99859929,-27.83195630,498072102.68513113,-5.85730835​E-07,-4.92904907E-07,-29.70016708,30.34360464,"2014-05-21 17:02:18.610297 UTC",1661.38970276
"2014-05-21 18:00:00.000000 UTC",297.99754570,-27.83284395,498018635.95758665,-5.84918159​E-07,-4.93368856E-07,-29.70730913,30.35009671,"2014-05-21 17:32:18.788643 UTC",1661.21135695
"2014-05-21 18:30:00.000000 UTC",297.99649358,-27.83373243,497965156.36786187,-5.84103358​E-07,-4.93833141E-07,-29.71445857,30.35659630,"2014-05-21 18:02:18.967031 UTC",1661.03296824
"Kernels Used"
"ROSETTA/kernels/lsk/NAIF0010.TLS"
"ROSETTA/kernels/sclk/ROS_140501_STEP.TSC"
"generic_kernels/spk/planets/de430.bsp"
"ROSETTA/kernels/spk/RORB_DV_006_01_______00014.BSP"

K

No, they're all about the same as JPL. 17:30 is about the closest eyeballing it here, which is the time of observation. That's what kills me, it feels like it's too much to be a coincidence. It's either Rosetta or a very coincidental undiscovered minor planet.

Last Edited by Astromut on 05/23/2014 02:27 PM

OK so lets just do what climate modellers do. You tell me what result you want to see and I will tweak the model to produce it ;)

K

( yes everyone I'm kidding )

The only result I want is the truth, and the only logical outcome is a discovery either way.

If 17:30 is very close but not quite then what if you are seeing the exhaust plume in IR but that is not the exact location of Rosetta at that point and is in fact being produced at an angle to its direction of travel and expanding outwards from there?

K

Found a known asteroid in the frame during the burn, right where it should be, and it looks a good bit brighter than my Rosetta detection despite being predicted to be magnitude 19.6 (nowhere near Rosetta though, it's way down at the bottom of the frame). Rosetta, or whatever it is, is probably a good bit dimmer than magnitude 20. Another scientist informed me that this scope can go to magnitude 23 under ideal conditions.

Last Edited by Astromut on 05/23/2014 02:52 PM

Here is another time series in csv around 17:30


"State Vector Results"
"Calculation Inputs"
"Calculation type","State Vector"
"Target","ROSETTA"
"Observer","EARTH"
"Reference frame","J2000"
"Light propagation","To observer"
"Light-time algorithm","Converged Newtonian"
"Time system","UTC"
"Time format","Calendar date and time"
"State representation","Right ascension, declination, range"
"State Vector Results"
"UTC calendar date","Right Ascension (deg)","Declination (deg)","Range (km)","d Right Ascension/dt (deg/s)","d Declination/dt (deg/s)","d Range/dt (km/s)","Speed (km/s)","Time at Target","Light Time (s)"
"2014-05-21 17:15:00.000000 UTC",297.99912663,-27.83151279,498098831.22951770,-5.86136433​E-07,-4.92673050E-07,-29.69659849,30.34036114,"2014-05-21 16:47:18.521140 UTC",1661.47885958
"2014-05-21 17:20:00.000000 UTC",297.99895081,-27.83166061,498089922.07157270,-5.86001286​E-07,-4.92750327E-07,-29.69778785,30.34144213,"2014-05-21 16:52:18.550858 UTC",1661.44914183
"2014-05-21 17:25:00.000000 UTC",297.99877503,-27.83180844,498081012.55679350,-5.85866087​E-07,-4.92827613E-07,-29.69897738,30.34252330,"2014-05-21 16:57:18.580577 UTC",1661.41942289
"2014-05-21 17:30:00.000000 UTC",297.99859929,-27.83195630,498072102.68513113,-5.85730835​E-07,-4.92904907E-07,-29.70016708,30.34360464,"2014-05-21 17:02:18.610297 UTC",1661.38970276
"2014-05-21 17:35:00.000000 UTC",297.99842359,-27.83210419,498063192.45653410,-5.85595529​E-07,-4.92982210E-07,-29.70135695,30.34468617,"2014-05-21 17:07:18.640018 UTC",1661.35998143
"2014-05-21 17:40:00.000000 UTC",297.99824793,-27.83225209,498054281.87094620,-5.85460168​E-07,-4.93059521E-07,-29.70254701,30.34576789,"2014-05-21 17:12:18.669741 UTC",1661.33025892
"2014-05-21 17:45:00.000000 UTC",297.99807231,-27.83240002,498045370.92831460,-5.85324751​E-07,-4.93136841E-07,-29.70373725,30.34684979,"2014-05-21 17:17:18.699464 UTC",1661.30053521
"Kernels Used"
"ROSETTA/kernels/lsk/NAIF0010.TLS"
"ROSETTA/kernels/sclk/ROS_140501_STEP.TSC"
"generic_kernels/spk/planets/de430.bsp"
"ROSETTA/kernels/spk/RORB_DV_006_01_______00014.BSP"

K

Thanks, it's not a matter of time series though. The expected track of Rosetta, both according to JPL and the kernels you're working from, goes right by this spot, but it doesn't really get any closer to it than at the time of observation.

Dr., how old were you when you first started telescopically exploring?

Well how close does it get? If you took the exhaust velocity of the gas ( 3 km/s ) and the time it had been produced for, could it cover the distance between the predicted track ( 0.75 km/s ) and what you saw?

K

About 14 or so.

Alright, good news, bad news. Bad news first, I just confirmed this was not Rosetta. Now the good news, I have discovered a new asteroid that happened to be very close to Rosetta's expected location during the burn. There's another rock out there, and I'm the first to have seen it!! Not what I was originally going for, but it's a real discovery anyway, so I'll take it. I just took another image of it using an even larger telescope. I assumed for a moment that my alternative hypothesis was correct, that this was an undiscovered asteroid. I searched for it based on the assumption of the average speed and general direction of a typical main belt asteroid... and found it in the new image. I traced back along that line and found it faintly detected in the image I took yesterday. I'll finish doing to astrometry and orbit analysis using all of these images later tonight and submit the discovery to the minor planet center. This should mark my first official minor planet discovery as an amateur astronomer! At first glance though it appears to be moving in a manner consistent with a main belt asteroid.

Last Edited by Astromut on 05/23/2014 04:18 PM

Hey Astro well done! nice when all your work, which I love comes together.

Well done Dr Asteroid!

That's awesome!!


Congratulations Doc!!!!

You've deserved it! Congrats Dr!

Here is the big brother of Rosetta's thrusters test firing. Imagine four of these running continuously for 8 hours, that looks like a lot of heat to dissipate.



[link to www.youtube.com]

.

So when minor planet 2014 KC1 gets an official name should it be called Nibiru, after all people have been waiting....

Congrats, Astro.


I can imagine the next RubeTube videos of BPEarthClown and 00SkyView: "NASA shill discovers Nibiru."

:)

.

Rosetta anyone?


[link to www.youtube.com (secure)]