VV Cep this night

VV Cep 2017-2019 Campaign
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VV Cep this night

Postby JJ Broussat » Mon Aug 07, 2017 10:10 am

Bonjour,
Voici le profil de cette nuit.
Cordialement.
Jean-Jacques

VV_Cep.png
VV_Cep.png (6.18 KiB) Viewed 2571 times
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Re: VV Cep this night- suite

Postby JJ Broussat » Mon Aug 07, 2017 10:26 am

Pour le profil pris à l'OHP, j'avais une résolution de 10840.
Cette nuit, en région parisienne, la résolution est de 15840.
Le setup est le même. Il a été démonté/remonté pour le trajet.
Aurai-je mal focalisé à l'OHP?

Merci
Cordialement.
Jean-Jacques
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Re: VV Cep this night

Postby jack martin » Tue Aug 08, 2017 8:56 pm

Jean-Jacques,

Well done on keeping up the monitoring.

I see no change in the spectrum yet

We have to keep observing.

A network should be setup for monitoring 24/7, but how ?

Regards,

Jack

Essex UK
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Re: VV Cep this night

Postby Ernst Pollmann » Wed Aug 09, 2017 7:38 am

Jack,
what does this mean: A network should be setup for monitoring 24/7, but how ?

Ernst
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Re: VV Cep this night

Postby marcoastro+ » Wed Aug 09, 2017 9:44 am

Hi Jack and Ernst,

Indeed, no major changes yet.
My last spectrum is from August 7th, I had a chance of a short time clear sky, just between two heavy rain showers, thunder and lightening.

VVCEP_07082017TRYPSTM.jpg
VVCEP_07082017TRYPSTM.jpg (40.06 KiB) Viewed 2503 times



For a while now the Peakheights of the V-component reside somewhere between 3 and 3.5 while the R -component fluctuates between 2.20 - 2.5.
Assuming mass transfer has taken place earlier, it is quite possible the predicted/calculated start of the eclipse will be later. If it is 68 days later then we can expect it to happen around the beginning of October! We could have a more precise guess if we know the orbital movements of both stars over the last year.

Monitoring on a "nightly" basis is possible if we can use a remote spectroscopy installation. Of course this is a quite expensive project, but with a team doable.
A nice place could be found with the e-Eye project.
http://entreencinasyestrellas.es/

Kind regards,
Marc.
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Re: VV Cep this night

Postby Robin Leadbeater » Wed Aug 09, 2017 11:04 am

Hi Marc,

Spectroscopy using remotely operated telescopes is tough to do. There are lots of robotic scopes around for amateurs to use but as far as I am aware none are equipped with spectrographs. Do you know of any remotely operated high resolution spectrographs available for amateur use? AAVSO purchased eShels a few years ago for a couple of their robotic telescopes but never successfully commissioned them. They do have a couple of Star Analysers though, installed filter wheels on a couple of their telescopes which can be accessed remotely, though as far as I can tell, nobody uses them.

Robin
LHIRES III #29 ATIK314 ALPY 600/200 ATIK428 Star Analyser 100/200 C11 EQ6
http://www.threehillsobservatory.co.uk
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Re: VV Cep this night

Postby marcoastro+ » Wed Aug 09, 2017 12:27 pm

Indeed, Robin, not so evident, but as remote-astrophotography has known its evolution, remote spectroscopy is coming after.
Several projects will appear in the near future.
A nice project, I'm following, is the IOWA Robotic Observatory which is testing this summer a new Echelle medium resolution spectrograph to be used for remote spectroscopy.

http://astro.physics.uiowa.edu/iro/equi ... meter.html


Kind regards,
Marc.
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Re: VV Cep this night

Postby Ernst Pollmann » Wed Aug 09, 2017 12:41 pm

Hi Marc,
you wrote:
Assuming mass transfer has taken place earlier, it is quite possible the predicted/calculated start of the eclipse will be later.

In that context Phil Bennet wrote here at the forum:
http://www.spectro-aras.com/forum/viewtopic.php?f=19&t=1219&p=5533&hilit=bennet#p5533

“The stars appear to be well-separated, and the M supergiant never comes close to filling its Roche lobe. There is mass accretion onto the hot companion, but this is from *wind* accretion -- gas from the wind of the M supergiant that just happens to be intercepted, and gravitationally captured, by the hot companion.”

Furthermore we are at present still around the phase of the apastron (phase 0.63; based on the orbital elements of Wright 1977) what means, there can not be explicit mass transfer in that orbital phase between the components, the distance between the M star and the hot companion is approx. 10-15 AU. As at all, mass transfer takes place only around the phase of the periastron.

Even if the eclipse comes later than the prediction says, there is no reason to become un-patiently. Until now the ARAS community has been able to observe a very well defined base line for both, the EW and peak height. If I see what quality in terms of the definition of the starting point during the last eclipse Kawabata et al. and Möllenhoff/Schaifers have achieved, I would say that our results until now are much better.

And in addition we are in the lucky position to have someone in our community, who contributes with his two remote observatories as much as it possible: Joan Guarro from Barcelona. Joan offers echelle spectra in a high quality which meet all what we could get.
So, from my point of view we should be patiently as we did until now.

Best wishes,
Ernst
Last edited by Ernst Pollmann on Wed Aug 09, 2017 4:39 pm, edited 1 time in total.
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Re: VV Cep this night

Postby Andrew Smith » Wed Aug 09, 2017 12:44 pm

Marc & Robin, Remote operation is certainly possible with the right software and hardware. The Liverpool Telescope is run completely autonomously and has, if I recall correctly, two spectrographs. At the other end of the scale I operate my R ~ 8000 echelle autonomously but close by ( I manually open and close the roof). It will soon be joined by a second R ~ 20,000 spectrograph both fiber fed via a Shelyak Fiber guide head as used on the eShel.

Regards Andrew
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Re: VV Cep this night

Postby marcoastro+ » Wed Aug 09, 2017 1:25 pm

Hi Ernst,

With the text: " assuming mass transfer has taken place earlier " I had in mind a possible mass transfer at the former peri-astron of course by a wind driven mechanism ,as the Roche lobe is not filled. That is called a dynamical mass transfer. When the wind was strong enough at that time this could have had an underestimated factor contributing to the mass transfer.

Anyway, as you write so correctly, we must be patient, of course.
Nevertheless VV Cephei is a tough couple of binaries and is challenging science the same way.
I'm glad to make some "minor" contributions to this excellent effort by amateurs.

Kind regards,
Marc.
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