VV Cep in near UV (R=3500)

[James Foster]

Here is VV Cep's spectra in near UV (3790-4110A) from last night with a JTW L-200 spectroscope using a 1800 l/mm grating and processed in Isis V5.8.0:

I can still see the hot B8 star's spectrum! This was a fairly long exposure (8x600sec, 2x2 bin) with the CDK17" telescope working at F6.8. Note that a low-pass Gaussian filter
was applied to make the spectra "less-noisey." I also took concurrent photometry with an ST-8Xe and 200mm lens which I'll process shortly.

James

[Ernst Pollmann]

James,
can you recognize any hints of a already beginning eclipse compared with your earlier spectra?

Ernst

[Peter Somogyi]

James, the L200 works superior in the UV at this wide coverage !
I also continued my serie in past year + last month around Ca II with the 2400/mm grating, will come up with it soon also.
What I can surely say so far, the absorptions vary on a shorter timescale (say weekly/monthly), need a continuous coverage to tell anything.
It would be nice to have them collected somewhere, so that we could do math on them in overall.
Maybe we also need to shoot Alp Ori or Mu Cep and include it somewhere, and remove the M component caused change in continuum so that we can determine EWs in longterm properly. Of course, please argue as I'm only a beginner amateur to do such.

Cheers,
Peter

[James Foster]

To: Ernst,

I do not have the spectra reduction skills to calculate this, but going on appearance from my last CaK spectrum taken quite awhile ago (26Dec16),
The intensities of the Balmer series are somewhat reduced at present time; see:

---NOTE: This was only processed in Bass 1.96 (no Isis processing) and without benefit of Flat...no Alpy calibration module at the time.---

I'm shooting Ha & Hb tonight. Will post them here after I get to work after local lunch time.

James

[Ernst Pollmann]

Related to our base line monitoring a Halpha spectrum would be fine.

Ernst

[James Foster]

Here are my Ha & Hb observations of VV Cep taken last night (07July17) processed in Isis V5.8.0 & 1D plotted in Bass V1.97:

Ha:


Hb:


The Ha was shot at 2x2 bin for 7x180 sec exposures through the CDK17 reflector working at F/6.8. The Hb was shot at 2x2 bin for 7x300 sec exposures with the CDK17 reflector also working at F/6.8. I will try to get a long (100-120 min shot) on VV Cep at the CaK wavelength before the weekend is over.

James

[Ernst Pollmann]

great, James!
Where can I find the spectra?

Ernst

[James Foster]

RE:"Where can I find the spectra"....will email them to you Ernst.

Here is my last CaK region spectrum of VV Cep, taken with the CDK17 at F/6.8 and L-200 with 1800 l/mm grating:

As usual, processed in Isis V5.9.0 and 1D graphed in Bass V1.9.7. I used the Miles star HD188512 for my IR correction in the CaK band.
Some intensity differences are shown btw the H-Balmer lines from the spectrum taken 2 days ago. My guiding, exposure time (100min) and flat
quality probably contribute more to the spectral differences than the star's behavior. Unlike my 06Jul17 CaK spectrum, I did not apply a
low pass Gaussian filter. Here it is with a Gaussian filter (Note shifted -1.6A relative to first version):


James