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RR Lyrae maximum for 14/07/2014

PostPosted: Thu Jul 17, 2014 1:14 am
by Tim Lester
This was a practice run at acquiring a series of 6 min spectra for RR Lyrae on the night of 14/07/2014.
I used HD184875 and its Cflib spectrum as the reference.
I am pleased with this first attempt. The shock wave Halpha line emission is clearly visible.

(Full spectrum animation does not seem to play unless you click on it)

RR_Lyrae_20140714_anim_Ha.gif (517.53 KiB) Viewed 3793 times


Re: RR Lyrae maximum for 14/07/2014

PostPosted: Sat Jul 19, 2014 8:55 am
by Paolo Berardi
Time resolved optical spectrum with a medium resolution, that is fantastic Tim, congratulations!
Are you involved in the current RR Lyr campaign?


Re: RR Lyrae maximum for 14/07/2014

PostPosted: Sat Jul 19, 2014 9:26 am
by Christian Buil
Hi Tim, really excellent.
I suggest to look also near HeI 5876 A line for some activity (but very low contrast feature if exist).
Could you indicate setup (tel. spectro, resolution) and the more important here, the time résolution (exposure time).


Re: RR Lyrae maximum for 14/07/2014

PostPosted: Sat Jul 19, 2014 11:30 pm
by Tim Lester
Thank you Paolo and Christian.

No I haven't joined the RR Lyr campaign yet. This was a trial run first to see how things went.
Unfortunately we are getting very few clear nights at the moment so the probability of a maximum and a clear night is not great.

To answer Christians questions. This series used 360 sec exposures and with the readout time included the interval came to about 372 sec.
The telescope is a home built 310 mm corrected Dall Kirkham cassegrain. The spectrograph is also home built.
I have described it on this forum previously - here is the link:
And Christian - thank you - I went to your web site hundreds of times for information during the design and building of the spectrograph.
I can reach a resolution of 2.8 A FWHM over much of the visible range, but focus of the camera lens is critical and I do not always achieve this.
For this series of spectra ISIS reported a resolution of 1815.

The Ha animation was just a magnified view from the full spectrum. I have done another one showing the He1 to Ha region. Christian you are right. The He1 absorption/emission feature is visible at the same time as the shock wave feature shows up in the Ha line.

RR_Lyrae_He1-Ha-anim.gif (604.79 KiB) Viewed 3758 times