CH Cyg 2018

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Re: CH Cyg 2018

Postby Vincent Bouttard » Fri Jul 20, 2018 5:00 pm

Hi all,

Please find my contribution to this topic with a low resolution spectrum taken during the last OHP workshop.
20x30s with Alpy600 spectrograph on 250 mm F/4 Newtonian telescope.

Vincent
Attachments
CH_Cyg_20180716_071.png
CH_Cyg_20180716_071.png (5.42 KiB) Viewed 880 times
VBO @ ARAS database : Newtonian 250 mm F/4 / Alpy600 / Atik 460EX
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Re: CH Cyg 2018

Postby Vincent Bouttard » Thu Jul 26, 2018 7:50 am

Hello

CH Cyg last night. 20 x 30s with Alpy600 on 250 F/4 Newtonian telescope (I've made a mistake on the title of this image about the exposure time).

CH_Cyg_20180725_882.png
CH_Cyg_20180725_882.png (5.25 KiB) Viewed 858 times
VBO @ ARAS database : Newtonian 250 mm F/4 / Alpy600 / Atik 460EX
Vincent Bouttard
 
Posts: 41
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Location: Colmar (France)

Re: CH Cyg 2018

Postby Francois Teyssier » Thu Jul 26, 2018 5:14 pm

CH Cyg returns to its previous luminosity
CHCyg2.PNG
CHCyg2.PNG (6.77 KiB) Viewed 833 times


Last Echelle spectra:
http://www.astrosurf.com/aras/Aras_DataBase/Symbiotics/CHCyg.htm
CHCyg3.PNG
CHCyg3.PNG (40.55 KiB) Viewed 833 times


Of course, we undergo high cadency monitoring until the return to previous state

François
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Re: CH Cyg 2018

Postby Peter Somogyi » Thu Jul 26, 2018 7:14 pm

Hello Francois,

I think the H-beta is considerably affected by the B component's flux level - hence can be mixed by a similar absorption that's prominent clearly in the UV:
chcyg_pso_0526_0720_h8vel.png

The green line is my new observation, unfortunately got bad weather here and can't shoot for 1-2 weeks.
What I suspect, the jet in the line of sight is precessing towards the 0 km/s vrad (maybe approached it by now).

I'd rather recommend looking at the sudden EW(H-alpha) drop happening since 07.12 - that's what the daily spectra show in the database, just cannot graph so many data.

Cheers,
Peter
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Re: CH Cyg 2018

Postby James Foster » Mon Sep 03, 2018 2:38 pm

Here is what I got on CH Cyg last week using the LhiresIII with a 1800 l/mm grating with 35 micron slit:
Image
I'll try getting it at CaK and Hb when the clouds go away!

Sincerely Yours,

James Foster
Los Angeles, CA
James R. Foster
Lhires III (2400 & 1800 ln/mm Grat) Spectroscope,
LISA Visual & IR Kit Spectroscope,
Alpy 600, and Star Analyzer 200
James Foster
 
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Re: CH Cyg 2018

Postby Peter Somogyi » Sun Sep 16, 2018 12:20 pm

CH Cyg went into a blue minima again (see aavso).
By fortune with yesterday session, I've got 2 spectra close by 1 week showing high & low state having their own flux (using the wide slit, ref.: Vega/calspec):
chcyg_high_and_low_20180915.gif
chcyg_high_and_low_20180915.gif (54.33 KiB) Viewed 574 times

Included my spectrum on 2018.07.07 which was in the middle of the earlier minima.
I am curious what is causing these events.
Peter
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Re: CH Cyg 2018

Postby James Foster » Mon Sep 17, 2018 9:48 am

To: Peter,

RE:"...I am curious what is causing these events."
Not sure about this myself, but here is my LhiresIII CaK data using the 1800 m/ln grating and 35micron slit (08Sep18) in the same near UV region:

Image

Here is a 2D i did to more clearly see the processed Isis 2D _CH CygCaK.fits file via PS motion blur filter.

Image

Let me know if you see anything strange here, as the short end of the spectrum sometimes does not "line-up" with the H-lines like the center and high end do.

James
James R. Foster
Lhires III (2400 & 1800 ln/mm Grat) Spectroscope,
LISA Visual & IR Kit Spectroscope,
Alpy 600, and Star Analyzer 200
James Foster
 
Posts: 253
Joined: Sun Jan 24, 2016 7:14 am

Re: CH Cyg 2018

Postby Peter Somogyi » Mon Oct 01, 2018 7:33 pm

This lucky weekend (3-days serie) allowed to follow the rise after this 2nd dip again, presenting within the whole month:
CHCyg_pso_201809.gif

Each spectra flux calibrated (ref: Vega), using the wide slit.

Peter
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Re: CH Cyg 2018

Postby Peter Somogyi » Sun Nov 18, 2018 11:17 am

Hello,

Just reporting a sudden flux drop of CH Cyg in the 3860-4000A range from OCT.30 to NOV.11, comparing to the previous low states:
drop_1030_1111.gif

It was extremely hard, switched to 20 minute to get real photons at low ADUs (with clouds in between).
The flux capture with the wide slit was yet at good sky conditions (Alpy Lyr + 2 x 5 minute CH Cyg), but had to do atmospheric correction (10% lower level than without the correction). The emissions with similar integrated flux amount confirming the continuum drop.
With pink color, showing hd207076 that I've scaled it via a rough human eye estimate (that when I subtract, then emission features become symmetric).
I'd assume, it should be a must for the Alpy owners to follow the decrement, and observers should make sure the low level in the UV is properly exposured.

During october, the flux level was flickering between low- and medium level (of 2018):
evolution_october.gif

The emissions flux level were a kind of constant, except 1-2 observations.

- Peter
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