Stage Spectro - OHP 2016

Olivier Thizy
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Stage Spectro - OHP 2016

Post by Olivier Thizy »

Hello,


the OHP spectroscopy workshop will take place on august 9th to 14th of 2016. The workshop is already a success with a lot of attendies including astrophysics students and new comers.


Here is a list of possible interesting targets that we sent to the attendies; but I felt it would be nice for those not attending to have the list and maybe try some of those from home... so here it is! Thank you for François Teyssier & Steve Shore for participating to this target list.


BEGINERS
If you are starting in spectroscopy, make sure to get a copy of Richard Walker spectroscopy atlas (specially the section 33 : spectral classes of important stars ; and section 35 : bright nebulae sorted by excitation classes) :
http://www.ursusmajor.ch/downloads/spec ... nglish.pdf

and a copy of François Teyssier «low resolution spectroscopy observer's guide » :
http://www.astronomie-amateur.fr/Docume ... ion_En.pdf

Look also at Richard Gray atlas :
https://ned.ipac.caltech.edu/level5/Gra ... tents.html

For stellar classification, concentrate on the blue part of the spectrum to see the Ca II and Na I lines (ie : 3800-6000A). This is ideal for low resolution.

In general, WR stars are ideal for showing what you can do with lower resolutions:
V444 Cyg, WN-Wolf-Rayet star (binary) with LOTS of history and easy and well placed (V<9). CQ Cep: as a comparison with V444 Cyg, about the same magnitude.


OHP 2016 - MAIN TARGET
Our top target for this year will be BF Cygni, a ~mag 10 symbiotic star which currently shows some jets.

See : http://www.spectro-aras.com/forum/viewt ... f=5&t=1466


EXERCISES
Spectral calibration in intensity, even in relative spectroscopy, is critical in low resolution. A good exercise is to observe a standard star as it rises and sets, one spectrum every hour, to obtain the transmission curve with wavelength *and* see what Rayleigh scattering really means (with a single star and standard star the absolute variations don't matter).

Also, use ESO standards :
http://www.eso.org/sci/observing/tools/ ... ectra.html
Cross calibrate a couple of those standards (using one to recover the other and then compare with the atlases) to check your data reduction method.

With spectrograph where you can easily remove the mirror slit, take a spectrum with the slit and one without inorder to compare the flux. Measure the total flux per column and calculate how much you loose at slit entrance (seeing, guiding and telescope optical quality).


OTHER INTERESTING (PRO/AM) TARGETS
Look for active stars with variable spectra, and stars to watch change in the source of a week's observation: RS CVn stars (active chromospheres, detached or semi-detached binaries) -- for these stars, the Ca II H,K lines arer the key observation, the rest of the spectrum is almost invariant: Z Her, RS CVn, lam And… del Cep is also important because it's a standard and you should will see variations in a few nights; 89 Her and UU Her are neat supergiant freaks and not too faint. The active sigma CrB can be observed too.

For the end of the night, WZ Cas, one of the best C stars in the sky, for low res.

For any active stars, the Ca II H and K are the most important lines, but anyone who can get the Ca II lines at 8664A would see a new world.

Spectrum variables, where the stars are strongly magnetic and there are line variations (absorption) over the rotational period. This is a good way to see how things change spectrophotometrically, and there has been very little work on that at moderate-high cadence: alpha2 CVn (12 53 41.49 +38 35 16.9), beta CrB (perhaps not as interesting but an old friend), eps UMa; alpha And (subtle)

Observation of a standard star: eta UMa. This is a very good one to practice on, it's the UV standard and also important for optical calibrations so one to use to practice calibrations. Of course, there's always Vega and 108Vir (an equatorial standard), A good exercise is cross calibration of several of these.


Take spectra of several pecular stars: alpha Sco (Antares), eta Aql…
* P Cygni : a really interesting star ; in high resolution try to mame an atlkas of all the lines and compare with lower resolution spectra…
* alpha Cyg: this is to provide comparisons of giant spectra, and a comparison with alpha Lyr to drive home how an A star illustrates luminosity class, it also emphasizes spectral classes.
* a spectrum of bet CrB would also be a very good idea since that's well placed and bright and also show an A-preculiar spectrum
* one interesting star, worth trying at high resolution with an echelle, is lambda Boo. This is an A Star (a true freak, one that isn't at all well understood and the prototype of a class). Even at low resolution it's interesting.

U Cep: eclipsing binary, since I mentioned it in the last issue, it's one of the better Algol-type systems available and if we time it right it should be possible to see the Rossiter-McLaughlin effect (see the latest ARAS newsletter No 5). For active binaries, WW Dra and Z Her are good targets.

Symbotics of importance: AG Dra (always, high velocity star as well), CH Cyg, one to try V1329 Cyg = HBV 475 (faint, use low resolution, but very very interesting and very high excitation), EG And (also an eclipsing system), V1016 Cyg (compare with a spectrum of a nebula) – see Francois Teyssier detailed list.

Cataclysmics : SS Cyg a dwarf nova prototype, to compare with U Gem in the winter; see latest ARAS newsletter for more targets and current brightness.

zeta Aur types: 31 Cyg, 32 Cyg
* eps Aur : for very late birds, just before sunrise)
* VV Cep : a must do, one to follow, ; use broad coverage even if nothing seems to be happening ; long awaited eclipse is approaching !

novae: low resolution to medium,. broad coverage, on any you feel like doing! For old novae, it would be worth a try to get (low resolution, slits wide open, broad coverage) HR Del, V339 Del (faint), DQ Her; if you try any of these, be sure to take multiple shorter spectra and co-add. They're faint and you'll see mainly the peaks of the strongest emission ([OIII] usually).
Look at symbiotic nova HM Sge whic is nice at the moment.

Planetaries: Cat's eye nebulae (NGC6543, 151 years after Sir William Huggins !), NGC 7027, M 97 an comparisons with H II regions and supernovae (remember, M1 -- the Crab -- will be visible in the winter for comparison).
Look at ARAS newsletter N°2 of 2015 and Françoys Teyssier web for how to measure & calculate electronic temperatures and densities.

Look at some bright Be stars :
* beta Lyr: take one spectrum each night ; it shows what different parts of the spectrum show you about a system. Compare spectra of beta Lyr and and W Ser, the latter is still high enough (dec=-15 but that's not terrible).
* delta Sco and gamma Cas. Do *time series* with one or two spectra per night. Try to cooperate between different observing posts (say one in Hbeta, another in Halpha, another in He I 5876).

RR Lyr: this would be ideal to follow at different resolutions, each group taking spectra every hour. In two nights it will be possible to reconstruct the changes in profiles and radial velocities.

BW Vul : a period of less than 5h. Continuously acquire spectra every 2 to 3 minutes, and built the 2D time spectrogram and the animation showing pulsations and shocks.


Missing ideas ? Look at any Be stars ; check latest Be star newsletter (on ARAS web site) and look for targets on ARASBeAm web site :
http://arasbeam.free.fr/

Look also at ARAS web site, forum (well, this is where you are!) & database for ideas & latest news :
http://www.astrosurf.com/aras/
http://www.spectro-aras.com/forum/
http://www.astrosurf.com/aras/Aras_Data ... taBase.htm


Cordialement,
Olivier Thizy
Olivier Thizy
Posts: 370
Joined: Sat Sep 24, 2011 10:52 am
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Re: Stage Spectro - OHP 2016

Post by Olivier Thizy »

A question was asked among the OHP spectroscopy workshop participants: which reference star for BF Cygni?

>>JJB>>In the reference star finder, I found HD 180317 for the reference star for BF Cygni. Is it OK?

>>FMT>>Correct, you also have HD 189395
>>FMT>>Most importantly, there are several MILES reference stars, using the non de-red'ed catalog
>>FMT>>Here is a list around BF Cygni:
image001.png
image001.png (44.43 KiB) Viewed 10641 times

>>OTz>>For BF Cygni reference star, I would take a MILES star which is close by (the star marked 'ref' are the MILES ones; the P1/P2/P3 are Be stars with BeSS priority from last week); hd176437 seems a good & bright one:
Inbox.png
>>OTz>>Attached is the "object to observe" list I used to create this charte in PRISM v10...
20160719_BeSS_Ref.zip
List of BeSS Be stars with priority (from 19-july-2016) and MILES reference stars, in PRISM v9 or v10 'objects to observe' format.
(14.37 KiB) Downloaded 408 times

Cordialement,
Olivier Thizy
Olivier Thizy
Posts: 370
Joined: Sat Sep 24, 2011 10:52 am
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Re: Stage Spectro - OHP 2016

Post by Olivier Thizy »

Here is the updated MILES references + Be stars + key targets file I am using with PRISM v10. I updated with today's ARASBeAm priorities for Be stars...

I also included there an excel spreadsheet with the data. It is in three parts:
-my usual or current targets
-the Be stars. See also the ARASBeAm daily robot file: http://arasbeam.free.fr/robot/ObsC2A.txt
-the MILES stars I am using for reference stars
20160728_BeSS_Ref.zip
MILES reference stars, Be stars (with priority) & some key targets, to be used with PRISM software.
It also includes an excel spreadsheet with the data.
(45.09 KiB) Downloaded 406 times
Cordialement,
Olivier Thizy
JJ Broussat
Posts: 70
Joined: Fri Aug 17, 2012 2:59 pm

Re: Stage Spectro - OHP 2016

Post by JJ Broussat »

Thanks.
Jean-Jacques Broussat
JJ Broussat
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Joined: Fri Aug 17, 2012 2:59 pm

Re: Stage Spectro - OHP 2016

Post by JJ Broussat »

Hello,
In personal mails, Olivier proposed HD 176437, François proposed HD 189395.
François said me tu use Miles library.
So , I will use HD 176437 which is in the Miles Base, and able in ISIS.

My question is: with the Lhires III at 2400l/mm, for H alpha, is it important to use the Miles Base? I read the document about "dérougissement" from François. It's mainly in the blue part we need to correct the spectrum.

Regards
Jean-Jacques Broussat
Francois Teyssier
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Re: Stage Spectro - OHP 2016

Post by Francois Teyssier »

S'il y a une Miles dans la liste, comme c'est le cas ici, il est toujours préférable d'utiliser la Miles, dès lors que la différence de hauteur n'est pas trop importante.
Avec les autres étoiles, il y a toujours une incertitude 1. sur le type 2. sur le rougissement.
François
JJ Broussat
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Re: Stage Spectro - OHP 2016

Post by JJ Broussat »

OK
Merci
Jean-Jacques
Olivier Thizy
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Re: Stage Spectro - OHP 2016

Post by Olivier Thizy »

Hello,


prequel of the spectroscopy workshop at Observatory of Haute Provence yesterday... with already about 30 people there and the field full of telescopes/spectrographs!

Here are couple of images/animation from last night - a clear and beautiful night with a nice milky way; EOS5D Mark III + Samyang 14mm F/5.6 / 45sec ISO3200:
Long meteor
Long meteor
Long meteor (zoom)
Long meteor (zoom)
web_BN3A5782 Meteor-zoom.JPG (209.74 KiB) Viewed 10330 times
Bright meteor going over two frames
Bright meteor going over two frames
web_BN3A5855 Meteor-all.gif (1.78 MiB) Viewed 10330 times
Bright meteor going over two frames (zoom)
Bright meteor going over two frames (zoom)
web_BN3A5855 Meteor-crop.gif (1.54 MiB) Viewed 10330 times

Cordialement,
Olivier Thizy
Olivier Thizy
Posts: 370
Joined: Sat Sep 24, 2011 10:52 am
Location: in the french Alps...
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Re: Stage Spectro - OHP 2016

Post by Olivier Thizy »

OK... workshop has already started and François & Steve already filled up the white board with symbiotic star models! :-)


For those not here, here are some ambiance pictures:
Steve
Steve
François C.
François C.
Enza is looking at the white board... puzzled!
Enza is looking at the white board... puzzled!
François T. at the white board
François T. at the white board
François T. joined by Steve at the white board!
François T. joined by Steve at the white board!

OHP has been renovated (dining room, breakfast, Annexe...); very nice now!
New dinning room
New dinning room
New room for breakfast
New room for breakfast


Cordialement,
Olivier Thizy
etienne bertrand
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Joined: Mon Aug 31, 2015 11:26 am

Re: Stage Spectro - OHP 2016

Post by etienne bertrand »

Merci pour les photos c'est sympa d'avoir des nouvelles rapides ; c'est comme si on était un peu avec vous à l'OHP.
Passez une bonne semaine, pleins de bons spectres et de belles nuits étoilées avec des nuits fraiches pour que les capteurs CCD ne soient pas envahies de pixels chauds.
Bon OHP à tous !
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