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VV Cep in eclipse

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Robin Leadbeater's picture
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VV Cep in eclipse
Attached are a series of spectra of VV Cep covering 3800-4150A at R ~2500 (variable 3000-1500 across the range  due to LHIRES chromatism)
 
Note the loss of H Balmer emission, broadening of the Ca II H K lines and relative drop in continuum flux below ~4000A, particularly noticeable in the latest spectrum recorded 2017-09-26
 
Robin

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jack martin's picture
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Robin,

Robin,

Excellent work an interesting pattern.

What is chromatism ?

Regards,

Jack

Essex UK

Robin Leadbeater's picture
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chromatism

Hi  Jack

Chromatic Aberration.  The inability of a lens to bring all wavelengths to focus in the same plane. The LHIRES uses an achromatic doublet which shows the usual pronounced chromatism in the Violet/UV so the focus varies across the spectrum. 

Cheers

Robin

Robin Leadbeater's picture
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Comparison with AZ Cas

I saw the same changes in the similar system AZ Cas in 2012 as it entered eclipse and we lost the spectrum of the hot B star  (Though there is no H Balmer emission in AZ Cas)

http://www.threehillsobservatory.co.uk/astro/spectra_43.htm

Cheers

Robin

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updated spectra

Here is an updated plot including the latest spectrum from last night. There has been no further change in the past 9 days so it seems likely that the ingress phase is now complete at this wavelength.

Robin

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Current state of Halpha observation

Dear colleagues,
if you wants to be informed about the current Halpha observation state of the campaign, here the corresponding link:
http://www.spectro-aras.com/forum/viewtopic.php?f=19&p=9412#p9412

Ernst Pollmann