RR Lyrae

RR Lyrae is a pulsating star. It is the prototype of this "RR Lyrae" class of variable star with short period radial pulsations. It is part of the instability strip on the HR diagram.

There is a group of amateur astronomers who are actively monitoring this star spectroscopically (note that it is also actively monitored photometrically).

Couple of workshop took place at Observatory of Haute Provence (OHP) under the lead of the professional astronomer Denis Gillet with the participation of Philippe Matthias and astronomers from Marrakech & Oukamaiden observatory in the moroccan Atlas mountains.


Here are the video & the slides from april 2013 workshop at OHP:

* Spectroscopy with small telescopes (myself): Viméo (PDF)

* Shock waves (Guillaume Mathias): Viméo (PDF)

* Spectroscopy of variable stars (Philippe Mathias): Viméo (PDF)

* Spectroscopy and pulsating stars (Denis Gillet): Viméo (PDF)

* Principles of spectra data reduction (Benjamin Mauclaire): PDF

* Astronomy at Oukamaiden (Adbelmjid Benhida): Viméo (PDF)

* Spectroscopy with a LISA spectrograph (Thierry Lemoult): Viméo (PDF)

* Understanding the Blazhko effect (Denis Gillet): Viméo (PDF)


See also my previous post on this blog about may 2016 workshop with video and PDF of the talks:
http://observatoire-belle-etoile.blogspot.fr/2016/05/may-21-22-at-ohp-pulsating-stars.html


The group is described in this web site:
http://www.pulsating-stars.org/

On this web site one can see the ephemeris of the events, for exemple with tonight event on top line:

The spectroscopi event tonight was scheduled at photometric phase 0.91, around 25/08/2016T20h54m58s UT, so around 22h55 Legal Time and occurs during 10-20 minutes.

Because of uncertainty and in order to capture before and after the event, it is recommended to start 40 min before the scheduled time, so around 20h15 UT (22h15 TL). I started my observations of RR Lyrae at 19h45 (21h45) so well in advance...

Because the events is short in time (10-20min), I decided to take a continuous serie of 3min exposures. This led to a dynamic around 1500 ADU.


Here is one screen taken during the exposures. It is captured on my main PC at home as I observed remotely! :-)

I took two 3-min spectra and reduced them; dividing them gives a 'flat' curve which I measured the standard deviation giving me a Signal/Noise ratio around 22:

The Halpha is well in emission during the event but the interesting feature is the He I 5876 line which is seen in emission on four 3-min exposures:

HeI 6678 emission seems to be detected on 20h57 UT spectrum but it is very faint:

Nothing concluding at 4686A:

Note that the last three graphs have been done with MatLab and a script that I currently working on: otz_plot.m (it also use another important function called rfitsinfo.m). More to come on this later... But here are the three commands I used in MatLab console to plot those graphs - very convenient to use for me (ie: saves me lot of time!):
otz_plot 6520 6700 0 5 '@pro34-13.fits' -f '@pro34-14.fits' -f '@pro34-15.fits'  -f '@pro34-16.fits' -f '@pro34-17.fits' -f '@pro34-18.fits' -y 6620 6640 -t short -s 0.5 -c kbgrm -d s -p png

otz_plot 5840 5980 0 5 '@pro38-13.fits' -f '@pro38-14.fits' -f '@pro38-15.fits'  -f '@pro38-16.fits' -f '@pro38-17.fits' -f '@pro38-18.fits' -y 5655 5665 -t short -s 0.5 -c kbgrm -d s -p png
 
otz_plot 4680 4710 0 5 '@pro48-13.fits' -f '@pro48-14.fits' -f '@pro48-15.fits'  -f '@pro48-16.fits' -f '@pro48-17.fits' -f '@pro48-18.fits' -y 4685 4695 -t short -s 0.5 -c kbgrm -d s -p png

V335 Vul

V335 Vul is a symbiotic star, very red, Carbon star with a strange spectrum containing C2, CN... absorption bands (and not TiO as for classical red giants).

It is very faint but I was able to take a 4h15min total exposure time with the échelle spectrograph showing a spectrum with lot of details.

The spectrum is now on ARAS database for access by anyone:
http://www.astrosurf.com/aras/Aras_DataBase/Symbiotics/V335Vul.htm

 ALADIN field of view and the guiding image of V335 Vul (180° rotated view)

The computer which control the observatory is mainly running PRISM v10 software. The screen below shows top:
-the graph showing the maximum ADU around Halpha emission line (a way to control that the spectrum doesn't saturate or that the signal doesn't drop too much - this is a very useful new feature of PRISM)
-the tracking inspector showing the quality of the autoguiding
-guiding camera control panel
-the new electronic finder CMOS camera control panel

and bottom:
-the image of the electronic finder
-the 2D image of the échelle spectrum; the bright spot is the strong Halpha emission but one can also see lot of absorption features
-the dome control panel

 Observatory PC screen (PRISM v10 software)

I took the first 15min spectra and compared them, despite a very low Signal/Noise ratio, there seemed to have some interesting information available:

 The division is mostly flat and the standard deviation is actually the noise of the spectrum - I measured for the 15min exposures a SNR around 11:

Here is the 4h15min total spectrum and a zoom on Halpha and the red portion of the domain covered by the échelle spectrograph:

gamma Cas "Be stars" - 150 years after father Secchi !

I took a spectrum of gamma Cas tonight, exactly 150 years after father Secchi observed its spectrum and thus discovered those fantastic "Be stars" whose study still continues...



Here the article of the discovery and my 150th anniversary spectrum:

I also went deep tonight with long acquisition on V 335 Vul, a very peculiar but very faint and very red star - more on this in another blog!

Electronic finder

At last I replaced the finderscope with an electronic finder using an old PL1M (QHY5) CMOS camera and a C-mount lens:

 

The result is ok and with 10sec exposure I typically get good recognition of the field. Here is a comparison of the image seen by the eFinder and PRISM skymap (Zoom 16 = 7.5°x7.5° field):

I used Astrometry.Net to get the image astrometry and result is:

Size:5.13 x 4.11 deg
Pixel scale:28.9 arcsec/pixel
Orientation:Up is -175 degrees E of N (ok, not so bad)

The fiber tip at the main telescope is at coordinates X=300, Y=317 on this eFinder image.



A side note as I'm observing tonight. The Be star HD177648 is close to another well visible star. For the guiding, I  used a 20 pixels window to ensure the autoguiding doesn't pick the other star - it worked!

And the guiding window:

 

And some problem I am now facing... I updated the Gemini ASCOM to latest version and I find some strange behaviour. Somehow, I still have trouble handling the Losmandy mount with the Gemini system and some of the trouble seems software related. What is trange is that I have seen the same behaviour at OHP with the NEQ6 (EQMOD) and several map software including PRISM. There must be a parameter which is not set right somewhere. Anyway, the symptom is hat I goTo a target and the telescope goes to a location like 0.5° East. Need some more work to diagnose the problem and resolve it!

OHP spectroscopy workshop - Steve Shore video

AUDE (association) spectroscopy workshop at Observatory of Haute Provence (OHP) took place between august 8th to august 14th.


Here are the videos of Steve Shore on astrophysics and spectral analysis:

1/ August 9th - introduction to spectral analysis, Equivalent Width, why the sunset is beautiful and beyond the reddish color (diffusion)...
http://www.astrosurf.com/thizy/ohp2016/20160809%20Spectral%20Analysis%20101%20(OHP%202016).flv

2/ August 10th - line profile & how deep we are seeing the atmospheres
nota: sorry, 3 files due to technical problems!
http://www.astrosurf.com/thizy/ohp2016/20160810%20Spectral%20Analysis%20101%20(OHP%202016)-A.flv
http://www.astrosurf.com/thizy/ohp2016/20160810%20Spectral%20Analysis%20101%20(OHP%202016)-B.flv
http://www.astrosurf.com/thizy/ohp2016/20160810%20Spectral%20Analysis%20101%20(OHP%202016)-C.flv

3/ August 11th - "absorption lines are precious, emission lines are ambiguous", opacity, winds & jets
nota: sorry, 2 files due to technical problems!
http://www.astrosurf.com/thizy/ohp2016/20160811%20Spectral%20Analysis%20101%20(OHP%202016)-A.flv
http://www.astrosurf.com/thizy/ohp2016/20160811%20Spectral%20Analysis%20101%20(OHP%202016)-B.flv

4/ August 12th - flux calibration and ESO standard stars, stellar rotation, temperature & classification, pulsations, convection & turbulence, (exo)planets...
http://www.astrosurf.com/thizy/ohp2016/20160812%20Spectral%20Analysis%20101%20(OHP%202016).flv

5/ August 13th - binaries
some comments before
http://www.astrosurf.com/thizy/ohp2016/20160813%20Spectral%20Analysis%20101%20(OHP%202016)-A.flv
main talk
http://www.astrosurf.com/thizy/ohp2016/20160813%20Spectral%20Analysis%20101%20(OHP%202016)-B.flv

------------------------------------------------------------------------

Here is the video of Martin Dubs talk on meteor spectroscopy:
http://www.astrosurf.com/thizy/ohp2016/20160810%20Meteor%20Spectroscopy.flv

with the PDF file of the slides Martin used during his talk:
http://www.astrosurf.com/thizy/ohp2016/MeteorSpectroscopy%20OHP%202016%20Dubs.pdf


Here is the video of François Teyssier on atmospheric extinction, how to find the best reference star and MatLab tool for publication (including ARAS newsletter):
http://www.astrosurf.com/thizy/ohp2016/20160811%20Ref%20star%20importance%20-%20MatLab.flv


And some pictures of the workshop on my Flickr account:
https://www.flickr.com/photos/thizy/albums/72157672284547115


Enjoy !
Olivier

Observing under clear skies

Clear sky tonight - I am acquiring several spectra starting with my favorites VV Cep, P Cygni and couple of Wolf Rayet stars to prepare OHP workshop which starts on tuesday.

Here are several shots with the Canon EOS 5D Mark III and the new Samyang 14mm F/2.8 lens (used at F/5.6 with ISO 3200 and 30sec exposures):

 

inside the control room with the spectrograph in the open

inside the control room, practicing Go game!

Scopius and Sagittarius with milky way above the dome

Mily way above the dome

Milky way from home

view toward the North pole

view toward the North-East with Cassiopae rising & Cygnus way up the sky

the sky above the open dome with lights on

view from inside the dome, Delphinus constellation visible

Night meteor of august the 4th

On the night of august 3rd to 4th, I acquired a serie of long exposure with the EOS 5D Mark III DSLR and the Canon 24-105mm zoom (set at 24mm). I got lucky with a bright meteor just above my observatory dome:

Here is a cropped of the meteor ifself:

new Samyang 14mm f/2.8 lens

I received our new Samyang 14mm f/2.8 lens for the Canon. Here are couple of shots after a storm at home...

it continues...

A superbe night tonight with a very good seeing (guiding is done below 3" or 3.5pix on the Atik Titan and echelle fiber injection; this is rather unusual!) and sky brightness is given with the SQM at 20.7 (21 measured but I have a 0.3 offset - just can't remember which direction!)... so nice weather, while not for long, continues!

I am taking my fourth series with Rachel's Canon EOS 5D Mark III and the 24mm zoom mounted on the Polaris system for some horizon paning during the night. The goal is to do another timelapse; this one should be the best so far! So timelapse continues...



I have acquired several Be star spectra including QR Vul which I found in outburst a week ago. I confirm this outburst but I noticed some change in Halpha in the course of the week - a star to monitor as its activity continues!

Then I am watching the new Star Treck web serie. It is based on the original serie but with new actors and new scripts. Those fans have redone the sets and are doing a great job in making those films. It is called Star Trek continues...

Oh... and here is a picture of inside the observatory of me watching an episode of Star Trek continues... :-)