Pluto occultation 29-6-2015

[tonybarry]

There are already two threads with some info on this upcoming occultation of Pluto, so I thought to condense the info into one place for those who are interested.

The original predictions, from IOTA, the RIO group, and MIT are attached.

http://www.kuriwaobservatory.com/TT~14/20150629_Pluto_summary.html

http://devel2.linea.gov.br/~braga.ribas/campaigns/2015-06-29-16.923_IAG12jul_Pluto.jpg

http://occult.mit.edu/research/occultations/Pluto/P20150629/index.html

The latest prediction from the RIO group is also attached.

[EDIT] as of 12th June, another prediction from RIO and another prediction from MIT is available.

RIO:-
http://devel2.linea.gov.br/~braga.ribas/campaigns/2015-06-29_Pluto/2015-06-29-16.907_NIMA30may_avrg_Pluto.jpg

MIT:-
http://occult.mit.edu/research/occultations/Pluto/P20150629/index.html

Both predictions are converging somewhat, in that the MIT prediction has moved a bit north, and the RIO prediction has moved south. Interesting times !

The casual reader will perhaps note that these predictions are fairly widely divergent. It is not possible to say at this time which one is the most correct; so any observer between Indonesia and Antarctica is in with a chance for the event, and should consider observing.

The last link above, from MIT, has a very good section on Observing Notes. Well worth reading. This section may help to answer the difficult question on filters, observing times, etc; although the prediction is for NZ and Tassie it is worth reading for anyone in the souther hemisphere.

Jay Pasachoff from Williams / MIT also writes on the planethunters blog, with some very nice info on previous occultation results and what people are looking for with the June 29 occ.

http://blog.planethunters.org/2015/05/26/blocking-starlight-much-closer-to-home-2-this-years-pluto-occultation/

Regards,
Tony Barry
WSAAG

[deanm]

Tony - I'm somewhat astonished that the occultation path & timings cannot be more precisely defined in advance - we're not looking at a mere asteroid (Pluto used to be a bloody planet!).

Can New Horizon's emergent approach data be used (not by us mere mortal amateurs!) to refine geometries?

Dean

[Steffen]

I think it is the other way around. New Horizons needs accurate telemetry, and an occultation of a fixed star by the planetoid can go a long way to better aiming the space probe at the space rock.

[Blue Skies]

That is exactly right. And that is why it so crucial to observe this event - it will provide data for any final adjustments that need to be made to New Horizons as it approaches Pluto.

Dean - I found this out a few years ago and was as astonished as you. I think some of the problem comes from the huge swing between Pluto and Charon, with the barycentre outside the surface of Pluto. Have you seen that animation of them orbiting each other? Huge wobble. This is also part of what makes Pluto so interesting!

[tonybarry]

Hi Dean,

Steffen and Jacquie have answered better than I could. And yes, it seems astonishing that we have such a poor grasp of the orbit of Pluto, and such a poor knowledge of the position of the occulted star.

But that is the current state of play.

When Gaia finishes its observing run an a couple of years, our astrometry will be ten times more precise than what we have now.

Also you may consider that Pluto has (as far as I know) the best determined orbit of any of the objects beyond Neptune. At least the uncertaintly is only about one planetary diameter. So there is still an awful lot of work to do even in the solar system to refine our knowledge, and this is work that amateurs can play a pivotal role in. Occultations of trans-Neptunian objects benefit greatly from amateur involvement. We may not have the biggest scopes or the coolest cameras, but there are enough of us to spread out widely and refine these orbits in a way that the professional astronomers cannot do.

As far as the info from New Horizons being able to refine our knowledge of the position of Pluto ... the uncertainties in all spacecraft motions require "mid-course corrections" at points along the way. So New Horizons' position is being refined as it gets closer to its target, which is good. Unfortunately, the occulted star's position is still not as well known. Astrometry is probably the biggest source of error, with the Pluto orbit being second. The post from MIT mentioned above has astrometry on the target star to about 29 milli-arc-sec, which is pretty good, but all the errors could push the path north or south by more than 1000 km (1 standard deviation of the error = 1097km).

The bottom line - observe first, and settle the question with direct measurements.

Regards,
Tony Barry
WSAAG

[astroron]

Am I right in saying this is for the 30/06/15 02:47 AEST.:question:
It might be a bit of a challenge visually as it is only two day to Full Moon. :(
Cheers:thumbsup:

[tonybarry]

Hi Ron,

Yes, you have the times right. The error in time (due to the prediction uncertainty) is a bit less than one minute. The occultation duration has a maximum of 99 seconds. The disparity between predictions is somewhat larger :-) so for safety, you would choose to observe for around five minutes either side of central time. I realise that would be difficult for a visual observer, but magnitude 12 stars would be doable in that 40cm Newt ! The magnitude drop is around 2 full magnitudes, so it would be easily noticed. The ingress and egress are not sharp, so you must consider that; more like a fade away than a turn off the lights.

Regards,
Tony Barry
WSAAG

[astroron]

Thanks Tony, I will give it a try weather permitting.
12 mag stars no problem for my scope. :D
My "Sky6 program gives a 12.2 star in that position and is occulted around that time,so will print off a chart and get the ARGO NAVIS to do it's thing and see how I go.:)
I have only ever had one successful Asteroidle occultation that is mainly due to the weather.
Fingers crossed.
Cheers:thumbsup:

[tonybarry]

The RIO group have updated their prediction for the Pluto occultation.

http://www.kuriwaobservatory.com/RIO_TNO_Events/20150629_65728l_summary.html

The path is now centred through Melbourne to Merimbula.

This should be seen as a prediction, and not the definitive result, which will only come by direct observation.

Those persons with PC computers can download the free OccultWatcher software and decide on the best spot to place their scope.

Regards,
Tony Barry

[DaveGee]

Occult Watcher (OW) can be downloaded here...
http://www.hristopavlov.net/OccultWatcher/publish.htm

For an asteroid (or Dwarf Planet) Occultation Observer, OW is a must-have software. It does the following;
- It automatically keeps up to date with the various prediction websites, and condenses all the info into one place where it's easily sorted.
- you enter your site coordinates, and it presents event criteria unique for your site; e.g. event time, target atlitude and azimuth etc.
- allows the observer to 'announce' their intention to observe an event. This is then propegated to all other announced observers, so everybody can see what is going on.
- allows printing of finder charts (two clicks) from C2A if installed.
- sends reminders via email and by on-screen messages if you are using the PC at the time.
- is linked into the reporting process to improve the quality and timeleness of the reports.
- and a host of other helpful features.
- and it's created by an an Aussie - Hristo Pavlov.

All this for the grand fee of AU$0.00 + GST.:eyepop:

[tonybarry]

The RIO group and the MIT group have both updated their predictions for this event. There is some serious interest here !

The RIO prediction can be found here :-

http://devel2.linea.gov.br/~braga.ribas/campaigns/2015-06-29_Pluto/2015-06-29-16.907_NIMA30may_avrg_Pluto.jpg

and the MIT prediction can be found here :-

http://occult.mit.edu/research/occultations/Pluto/P20150629/index.html

It is interesting that the MIT prediction has moved north, to encompass Melbourne and perhaps up to Euroa; while the RIO group prediction has moved south, with the northern limit a bit north of Brisbane.

While it's obvious they cannot both be correct, it does illustrate how difficult the task of such predictions can be; and the best advice is to observe if you are anywhere in the right hemisphere.

I have added the prediction images to the first post of this thread.

Regards,
Tony Barry
WSAAG

[DaveGee]

here is a GoogleEarth .kmz file...

http://www.kuriwaobservatory.com/RIO_TNO_Events/20150629_PlutoOccults-4U347-165728.kmz

hint...R'click and save target as...

[DaveGee]

Hi Tony,

one thing that is not apparent with the MIT prediction at first glance, is that it appears the northern 1-Sigma currently passes through Darwin.

The message here is don't fixate on the central shadow path, but judge the prediction on the width of the uncertainty zones.:confused2:

[tonybarry]

Hi Dave,

The dotted line is the 3-sigma on the MIT plots. Unlike everyone else's plots.

But yes, you are correct. The uncertainty is larger than we would like ...

Regards,
Tony Barry
WSAAG

[DaveGee]

Ooops. Thanks for the correction.

[Plutoholic]

FYI...
Here is the latest Epheremis.. It has moved further south as per Bruno Sicardy a world renowned reputed Occulatation tracker (from France - see his page, its amazing) working w/the Brazilian folks.. dated June 14th.. So probably just in Tasmania (if at all).. see the latest ephemeris below..

http://devel2.linea.gov.br/~braga.ribas/campaigns/2015-06-29_Pluto/2015-06-29-16.892_IAGavrgCFHT_NH_Pluto.jpg

Also: Andrew Cole at UTAS will be imaging it with the new 1.3m at Bisdee Tier Greenhill Observatory. He too should know the latest..

Also: Nasa & ESA's airborne observatory SOFIA (which is at Christchurch) will be above the clouds image the Occultation..
http://astro-en.shao.cas.cn/events/colloquia/201503/t20150305_282476.html

AND: One can for the 1st time watch the Occultation online LIVE..
http://main.slooh.com/event/see-pluto-occult-a-12th-magnitude-star/

There are many in the South Island imaging the event (if no clouds).. The RASNZ Occultation Section headed by John Talbot knows also the current info..

Also the BOOTES-3 telescope in Blenheim (South Island, New Zealand) is going to image it.. they too can advise the current ephemeris..

Who am I ?.. name: Raj Pillai an avid Pluto fan a co-admin of one of the most well read Facebook Pluto specific page called "Society of Unapologetic Pluto Huggers" welcome to join it.. Work closely w/the PI of the New Horizons mission.. Dr Alan Stern..
Any Pluto related help.. send me message.. Love your thread, so joined IceInSpace today.. not an imager..
Hope this all helps..
Raj Pillai

[tonybarry]

Hi Raj,

Thank you for the updates, and welcome to Ice In Space. I hope you have a good time here and enjoy the diverse crowd. Always something happening !

Are you involved with any astronomy groups in India ?

Yes Bruno's prediction has moved south, although I think to observe anyway. The current 1-sigma is around 400km for the RIO group, and about 1100km for the MIT group. So observations even 1000km north of Melbourne still have a reasonable chance.

As a aside, Andrew Cole might not actually want his email address publicised here. It might be good to confirm with him first before publishing it, to avoid him getting spammed.

Regards,
Tony Barry
WSAAG

[tonybarry]

News from the MIT crew - their prediction has moved north. Now Melbourne and perhaps as far north as Canberra is/are in the shadow. Previously their estimate was Launceston was at the northern extent of the shadow.

Link is here:-

http://occult.mit.edu/research/occultations/Pluto/P20150629/index.html

Error in distance (N -S) is 1038km 1 std dev.
Error in time (E-W) is 41 sec 1 std dev.

This means that sites as far north as Brisbane are in the 1 sigma.

It's not over till the lights go out behind Pluto ...

Regards,
Tony Barry
WSAAG

[Plutoholic]

Tony,
Thanks for the input... How can one delete A.Cole's email ID.. though I got it from a simple Google search..
Want to know how many are imaging from Aus this event.. Interested in the Movie of the image.. not the light curves..
Thanks, Raj

[pluto]

Just click "Edit" in the bottom right corner of the post.

[tonybarry]

Hi Raj,

Hugh has answered the question of the email address nicely. Thanks Hugh !

Regarding the video of the occultation. Well it has not happened yet but in general John Talbot from NZ will be collecting the reports, and the light curves. Many people also post the movies on line. I will try to advise on this page of web addresses if I find any have occurred.

Regards,
Tony Barry

[Blue Skies]

There's this video from 2008 by DaveG which shows you what a perfect capture is like: https://www.youtube.com/watch?v=WruS6own5qc

Because of Pluto's atmosphere it is a slow disappearance and reappearance, so it takes a while to look like anything is happening, unlike a normal asteroid occultation where the D and R are pretty sharp.

[Plutoholic]

Done.. thx Hugh..

[Plutoholic]

Brilliant.. Thanks, this what I hope we can get on June 29th too..

[Plutoholic]

Thanks Tony.. keep us posted.. seems like Brisee maybe in play..
Will alert my friends over there..

[Plutoholic]

The airborne observatory's plans for this June 30th 4.53 am NZ time..
Good video details (starting 1:40 mins into the video)..
https://www.youtube.com/watch?v=_hXIeecp8oU

Raj Pillai

[Plutoholic]

Hi All..
MIT group: (updated June 22nd)
http://occult.mit.edu/research/occultations/Pluto/P20150629/index.html

Rio: (updated today but data averaged from Obs taken June 8th thru 10th)
http://devel2.linea.gov.br/~braga.ribas/campaigns/2015-06-29_Pluto/2015-06-29-16.891_IAGavrgCFHT_NH99_Pluto.jpg

The MIT epheremis has moved South..
Weather update over NZ at around Occultation..
Clouds over lower South Island, but East coast from Blenheim down to Timaru and most of North Island could be good.

Fingers crossed..
SOFIA still has the best seat in the house..
Good read.. http://go.nasa.gov/1xKcTSe
Short video: https://www.facebook.com/187095228001013/videos/939513986092463/

Looks like Tasmania seems the safe bet for Australia..
Cheers,
Raj Pillai

[skysurfer]

I thought that this planetoid has no atmosphere so the entry or exit is sharp,just like a lunar occultation.

[Fivey]

See BlueSkies post below, and check out the video she linked to...

[DaveGee]

It turns out there's a rather easy way to locate the target star.

If you point your telescope at 5.0 mag. xi1 Sagittarii (= SAO 187498, J2000 RA 18h 57.3m, Dec. -20 deg. 39'), then turn off all tracking (or don't push your DOB), then 3 minutes 28 seconds later, the 12.3-mag. target star will be almost centred in the FOV.:thumbsup:

[DaveGee]

It 's suggested that observers intending to submit science measures perform a moccultation on the nights before or after event night.

BTW, moccultation = Mock-occultation... get it?:rofl:

The reason for this is primarily to get practise, however in the observations instructions at...
http://devel2.linea.gov.br/~braga.ribas/campaigns/2015-06-29_Pluto.html (wlmailhtml:{80B1B087-73FE-468C-87F5-3F91A512A1FE}mid://00000357/!x-usc:http://devel2.linea.gov.br/~braga.ribas/campaigns/2015-06-29_Pluto.html)
require...

quote
Night before and/or after the event: Pluto and the target star must be observed on the same field of view and same equipment, but not merged, at the same airmass (altitude).
This allows to calibrate the target against the reference stars, and then derive Pluto's contribution during the occultation. The exposure time for these calibration images can be higher than that of the occultation, to improve photometry
endquote

[gary]

Shevill Mathers (https://sites.google.com/a/astrotasmania.com/www/home), in Cambridge, Tasmania, kindly forwarded me the attached
article from the Hobart Mercury dated 27th June 2015.

Shevill has been entrusted by Professor Jay Pasachoff (https://en.wikipedia.org/wiki/Jay_Pasachoff), director of the
Hopkins Observatory in the United States, to observe and time
the occultation using an arsenal of equipment that Professor Pasachoff
has forwarded him.

We recently assisted upgrading Shevill's Argo Navis with the latest Argo Navis
Version 3.0.1 firmware and Shevill uses the Argo Navis to assist him in
locating Pluto.

We wish everyone the best of luck in their endeavours and clear skies!

Best Regards

Gary Kopff
Managing Director
Wildcard Innovations Pty. Ltd.
20 Kilmory Place
Mount Kuring-Gai NSW 2080
Australia
Phone +61-2-9457-9049
Fax +61-2-9457-9593
sales@wildcard-innovations.com.au
http://www.wildcard-innovations.com.au

[ChrisM]

Just got a break in the clouds and was interested to see how much difference the Moon made - fortunately not as much as I thought that it might.

The target (occultation) star is the brighter one almost dead centre (slightly below) of the image, and Pluto is the first object out at 5 o'clock (approx 25% of distance to edge of frame in 5 o'clock direction).

Exposure: 1.6 seconds
Other data from plate solve:
Center (RA, Dec):(285.186, -20.694) Center (RA, hms):19h 00m 44.718s Center (Dec, dms):-20° 41' 39.852" Size:22.1 x 14.7 arcmin Radius:0.221 deg

Orientation:Up is 54.2 degrees E of N

Let's hope for clear skies Tuesday morning!

Chris

[N1]

The event was observed (on screen) and recorded this morning from Beverly Begg Observatory, Dunedin. A very pronounced drop in brightness.

[rustigsmed]

nice, I was wondering if anyone nabbed it. :thumbsup: weather has been terrible.

[gary]

Shevill Mathers in Tasmania emailed me this morning and reported that
unfortunately he was bed-bound with a fever and loss of balance from the
flu. To add to his disappointment, he reported the night was clear.

[tonybarry]

At the moment, we know that SOFIA flying over the Southern Ocean did get the central flash. That's awesome. (Source:- Twitter, #PlutoOcc2015)

From OccultWatcher reports, NZ, four sites saw occultations, of 60 sec, 71 sec, 102 sec, and 120 sec. This would likely include the atmospheric ingress and egress, hence the length. Several other sites had issues. The most southerly observer in Tasmania did not see an occultation. At least two sites in NZ have not yet reported in.

All told there were forty three sites listed on OccultWatcher, from Northern Queensland to the south of NZ. This may well be a record for occultation observing and recording in the southern hemisphere.

At the moment, there are no YouTube clips of the occultation listed. These may surface in the near future.

A NZ news clip I have seen is here:-
http://www.3news.co.nz/nznews/clear-skies-for-plutos-stellar-occultation-2015063008#axzz3eXQREru8
The presenter is perhaps not as clued in as he could be, but Jay Pasachoff gets some airtime.

Regards,
Tony Barry
WSAAG

[Suzy]

Hi Gary,

that's such a shame to hear about Shevill :sadeyes: . He must be thoroughly annoyed and sad that he couldn't take part. He's been a great and helpful friend to me on facebook for many years and he was telling me about his part in this. No wonder he's been quiet on facebook today - poor thing - a blow physically and mentally :sadeyes:. He's one of the nicest people I've ever had the pleasure of knowing.
Thank you so much for the update.



Hi Tony,

Such great information you and others are providing on this thread. I have to admit much of it is doing my head in, but it's still so very interesting!

Anyhow, I thought you might be interested in this article. Raj Pillai posted it on his Pluto Huggers page over on facebook.
SOFIA had dramas as the path kept changing, even right up to the last hour! But phew, it came through in the end.

http://phenomena.nationalgeographic.com/2015/06/29/i-chased-plutos-shadow-across-the-southern-pacific-ocean/#comment-2579096


Nice image, Chris :thumbsup:

[ChrisM]

The clouds thickened on the evening of the occultation, so with 3.5 hours until target time, I reluctantly closed up my observatory and packed a couple of tripods and DSLRs plus a small scope in the car and headed east expecting to find the reported clear skies after about one hour of travel. No such luck - so I kept driving. After nearly 3 hours on the road, I finally got a break in the clouds and found somewhere to pull up off the road.

There was not much time left to set up the equipment, and the EON80 scope (500 mm FL) on a camera tripod is far from ideal. Clouds started to form, but at least I had some view. With the scope pointed somewhere in the general direction of Pluto, I took over 600 2-second images. The images are currently being uploaded to the team at MIT for analysis.

I got home after a 430 km unplanned outing feeling somewhat satisfied that at least I saw something, but have learned a few lessons on the way.

Cheers, Chris

[Blue Skies]

After a rechecking my video several times, as well as being told I must be within the limits of Pluto's atmosphere, I finally found the tell-tale dip of an atmospheric graze in the signal. I'm posting the light curve for you all to see as I don't think it gives any secrets away, or breaks any information embargoes, it just shows what kind of effect you get with this kind of thing. I have seen a curve from a NZ observer who saw a total occultation by the body of the planet, and it looks quite different to this, but still has the expected slow fade down to a base-level during the main event, then a slow fade back up. So knowing that my light curve is just atmosphere, its a bit different, but I'm still intrigued as to why it's not an even curve - the egress of the graze is steeper than the ingress.

ChrisM, John Talbot is interested in collating local results for the RASNZ Occ Section report on this event, but if you're working with MIT you might be embargoed? They are looking for other people who might have caught the atmosphere and we might be the only people in that zone. Dean Hooper was too far north, he went to Nagambie in hope of clear skies but got caught in fog. The Dunham's got clouded out but were further north again, anyway. I'm just thinking you might have been inside of me, as Dave Herald had planned to do a station at Bombala in NSW that would have been south of me also.

[DaveGee]

Nice one Jacquie!:eyepop:

Embargos - Plumbagos. As amateurs we can share our data with who ever wants it and can make good use of it.

From west of Sydney, it's not certain at all if we saw an event - see below... the blue readings - observed with the Evans-30 inch using our ADVS 14bit progressive scan GPS timestamed video system running at 7.5 frames per second (zero dead time).

[mr2ns]

Forgive me for not understanding all of this, I am a complete newbie... I had to Google occultation...

I am located in Perth, when will I be able to see Pluto? I am in the path to see the occultation? Over how long will it take?

[pluto]

This occultation happened a couple of weeks ago. However you could still image Pluto if you have the right gear. I think it's too faint to observe visually, but I'm not sure.

[tonybarry]

Hi mr2ns,

As Hugh has said, the occultation is over.

Pluto is still observable, but at magnitude +14 it is a camera object (unless you have access to a generously sized telescope (think 20" or better).

Regards,
Tony Barry
WSAAG