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  #21  
Old 23-12-2019, 08:53 PM
bgilbert (Barry gilbert)
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sorry dennis try the attachment

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  #22  
Old 24-12-2019, 07:21 PM
Dennis
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Originally Posted by bgilbert View Post
sorry dennis try the attachment

Attachment 253471
Thanks Barry, you nailed it, the comet is clearly visible centre frame.

I used 4 programs to plot the position; The Sky X Pro, Starry Night Pro 8, Sky Safari and SkyTools 4 and all of them indicated positions several degrees apart.

I made sure that I refreshed all the Comet Elements for each program via downloads and checked that my observing site and details were all the same and correct, so not sure why the variation - I suspect they must use different sources?

Cheers

Dennis
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  #23  
Old 25-12-2019, 09:36 AM
bgilbert (Barry gilbert)
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. G'day Dennis,
One of our club members, Chris Wyatt is a comet watcher and belongs to an international organization of some sort (I can get details). He monitors several comets on a weekly basis and submits details, the details are then used to update position mag. etc. The position of 2I/borisov may be still being upgraded, as of the 6 Dec. no southern hemisphere submissions had been registered, the submission by Chris, being the first in the southern hemisphere to observe it,
. I'm trying to convince a friend of mine who works at siding springs to to stick an eyepiece or camera on the 3.9m or the 2.3 m., they are not generally used any more for visual observing. The 2.3 m is a possibility, it just needs an adapter to be machined and to sneak in some time somehow, it's generally fully booked.
. The other possibility is the 41 inch Milroy telescope at Coonabarabran, it is now privately owned, but I have earned some time on it, by performing maintenance on it. At its peak it was mag.15.5, it will be receding now, but with big scopes should be able to track it for months, depending on smoke.
. The other possibility is, our club, has managed to acquire one of the only two Hewitt cameras in the world, look up Hewitt camera on web.
. We replaced the film handling stuff and machined up a camera holding device and fitted a ZWO APS-C cooled sensor (forgotten it part number).
. This camera is 24 inch aperture f1 schmitt with field flattener, 34 inch mirror, made by Grubb and Parsons and weighs 9 tons, we added a ton to it for some reason. The full story is on our club website.

http://www.tamworthastronomy.com.au/

Cheers,
Barry
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  #24  
Old 26-12-2019, 02:58 PM
Dennis
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Thanks for that Barry, and the link to the Tamworth Club - I enjoyed browsing around there.

If I were trying to hunt down 2I/Borisov (aka C4/2109 Borisov) I would start off with the JPL Horizons website as it has always been accurtae when I have been imaging NEO's and the fainter moons of Uranus and Neptune.

Cheers

Dennis
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  #25  
Old 10-01-2020, 10:17 PM
bgilbert (Barry gilbert)
barryg

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. G'day Dennis

. I thought you might be interested that one of our club members managed to image 2I/borisov with a 6 inch refractor, using about 5 minute integrate time with a cooled ZWO mono camera, and a good dose of smoke.
. It will probably appear on our club website shortly. We are contemplating registering our images on the Comet Observation Database COB, because there are no officially recorded images from the southern hemisphere, and we would like to represent Aussie amateurs.
. We could also provide assistance to iceinspace members on how to find, and image the comet with almost any telescope setup. The comet is about mag 15 or so at the moment probably fading to mag 20 in about twelve months and wont be returning any time soon, and remember it is the first interstellar comet ever observed.
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  #26  
Old 11-01-2020, 07:17 PM
Dennis
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Originally Posted by bgilbert View Post
. G'day Dennis
. I thought you might be interested that one of our club members managed to image 2I/borisov with a 6 inch refractor, using about 5 minute integrate time with a cooled ZWO mono camera, and a good dose of smoke.
. It will probably appear on our club website shortly. We are contemplating registering our images on the Comet Observation Database COB, because there are no officially recorded images from the southern hemisphere, and we would like to represent Aussie amateurs.
. We could also provide assistance to iceinspace members on how to find, and image the comet with almost any telescope setup. The comet is about mag 15 or so at the moment probably fading to mag 20 in about twelve months and wont be returning any time soon, and remember it is the first interstellar comet ever observed.
Thanks Barry and a big well done to to the person that managed to grab an image.

A few weeks ago I did have an opportunity (clear skies, no smoke ) but The Sky X Pro put me in the wrong place, so my FOV missed the comet by about 5 or 6 degrees...

Was your colleague tracking on the comet for the 5 minute exposure, as I assume it would show quite a bit of movement against the BG stars for that length of time?

Cheers

Dennis
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  #27  
Old 11-01-2020, 10:23 PM
bgilbert (Barry gilbert)
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G'day Dennis

. I will pass on your congratulatory comments to my colleague.
On the occasion in question he only tracked the stars, so the comet trailed slightly. He will have another attempt when the moon and smoke allow, using RGB filters, probably with half an hour for each colour, and attempt to track the comet.
. I have attached about a month out of an ephemeris that seems accurate so far, It has about two to three weeks left on it.
.
2I_Borisov_3rd Jan_2020.txt
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  #28  
Old 12-01-2020, 03:14 PM
gary
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Quote:
Originally Posted by Dennis View Post
Thanks Barry, you nailed it, the comet is clearly visible centre frame.

I used 4 programs to plot the position; The Sky X Pro, Starry Night Pro 8, Sky Safari and SkyTools 4 and all of them indicated positions several degrees apart.

I made sure that I refreshed all the Comet Elements for each program via downloads and checked that my observing site and details were all the same and correct, so not sure why the variation - I suspect they must use different sources?

Cheers

Dennis
Hi Dennis,

The problem originates at the Minor Planet Center (MPC).

2I/Borisov has a very, very high orbital eccentricity (in the order of ‎3.3575)
and the orbital elements are just the solution for a two-bodied problem.

The orbit is sufficiently perturbed that unless you are using very recent
orbital elements (check the epoch), the computed position will be
degrees out.

Something is up at the MPC. The elements they have been publishing
for the software packages for some comets have epochs that are
weeks and months out of date compared to the recent epochs used
for the orbital elements they also publish separately as raw data.

The asteroid elements for the software packages are even worse
where they were last computed for epochs in 2018.

Many of these orbits have been perturbed since then.

They had some computer system failures some time back and things have
been out of kilter since then.

The workaround is to use the data either they or JPL supply when
you examine an individual object and synthesise the elements from that.

How you then load your own elements into the package of choice I will
leave as an exercise for you but it may not be possible for all packages.

Alternatively, just use the MPC web page that allows you to compute the
RA/Dec position at multiple points in time, say every 5 minutes in the evening.
Those positions are accurate.
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  #29  
Old 12-01-2020, 07:26 PM
bgilbert (Barry gilbert)
barryg

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G'day Dennis and Gary.

. Stellarium 0.19.2 has two occurrences of 2I/Borisov, one of them is fine, the one on the left of the image after you load it. The ephemeris I posted is also fine, It's derived from Guide 9.

Cheers Barry
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  #30  
Old 13-01-2020, 07:01 PM
Dennis
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Quote:
Originally Posted by gary View Post
Hi Dennis,

The problem originates at the Minor Planet Center (MPC).

2I/Borisov has a very, very high orbital eccentricity (in the order of ‎3.3575)
and the orbital elements are just the solution for a two-bodied problem.

The orbit is sufficiently perturbed that unless you are using very recent
orbital elements (check the epoch), the computed position will be
degrees out.

Something is up at the MPC. The elements they have been publishing
for the software packages for some comets have epochs that are
weeks and months out of date compared to the recent epochs used
for the orbital elements they also publish separately as raw data.

The asteroid elements for the software packages are even worse
where they were last computed for epochs in 2018.

Many of these orbits have been perturbed since then.

They had some computer system failures some time back and things have
been out of kilter since then.

The workaround is to use the data either they or JPL supply when
you examine an individual object and synthesise the elements from that.

How you then load your own elements into the package of choice I will
leave as an exercise for you but it may not be possible for all packages.

Alternatively, just use the MPC web page that allows you to compute the
RA/Dec position at multiple points in time, say every 5 minutes in the evening.
Those positions are accurate.
Thanks Gary, I appreciate your insight into the problem.

In the end, it was 2 phased issues with The Sky X Pro.
  • First of all, TSX was not (originally) designed to handle objects with the large/unusual eccentricity of 2I/Borisov, but the Bisque Website provided what they reasonably believed to be a suitable, interim solution whilst also notifying their user community of a soon-to-be released Daily Build that would fix that issue.
  • Then, the interim solution proposed, which was to point the Comet Input dialogue to an external 3rd party set of elements, did plot the comet but unfortunately, there may have been some issue with the accuracy of those elements as the plotted position of the comet was a few degrees off.
The Bisque website also provided another solution, which was a Copy/Paste of the elements from the JPL Horizons website which did plot the real position, but by then, the clouds rolled in and have hung around so I havenít had the opportunity to try again.

Cíest La Vie.

Cheers

Dennis
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  #31  
Old 13-01-2020, 07:03 PM
Dennis
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Quote:
Originally Posted by bgilbert View Post
G'day Dennis and Gary.

. Stellarium 0.19.2 has two occurrences of 2I/Borisov, one of them is fine, the one on the left of the image after you load it. The ephemeris I posted is also fine, It's derived from Guide 9.

Cheers Barry
Thanks Barry, the good folks at Software Bisque have fixed the issue and I can also navigate (GoTo) 2I/Borisov using SkyTools 4, but if you could do something about this pesky cloud cover, I would certainly appreciate that.

Cheers

Dennis
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