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CH Cyg at high resolution

Posted: Tue Dec 02, 2014 9:42 am
by Tim Lester
Hi all

I had to wait for snow flurries to clear but I finally managed to get CH Cygni with my new 1800 lpm grating.
ISIS reports a resolution of 8898 so not quite 10,000, but good S/N.

Image

Image

Tim

Re: CH Cyg at high resolution

Posted: Sun Dec 21, 2014 7:46 pm
by Tim Lester
CH Cyg on Dec 19 - showing changes for Halpha since last observation on the 2nd.
_chcyg_Halpha.png
_chcyg_Halpha.png (7.75 KiB) Viewed 17017 times
Tim

Re: CH Cyg at high resolution

Posted: Sun Dec 21, 2014 9:31 pm
by Christian Buil
Hi tim,

Excellent spectra of red region!

(can you give more about your spectrograph setup : optical configuration, components, weight, images (?))


Christian

Re: CH Cyg at high resolution

Posted: Mon Dec 22, 2014 6:48 am
by Francois Teyssier
Hello Tim,

EXcellent. That perfectly responds to the request of Dr Skopal.
Of course, the fit is welcome in the database !

François

Re: CH Cyg at high resolution

Posted: Mon Dec 22, 2014 5:02 pm
by Tim Lester
Thanks Christian and Francois.

Christian,
Shortly after I joined the ARAS group I posted a description of my setup with photos here: http://www.spectro-aras.com/forum/viewt ... ?f=8&t=811
The important details are:
Telescope:
311cm home built corrected f9.8 Dall Kirkham with a 45mm dia. diffraction limited field.
Spectrograph:
- classical home built designed for low resolution
- f6.6 focal reducer built in to spectrograph mount
- 23 um slit (an APLY slit) gives 2.3 arcsec width after the f6.6 reducer. Reducer delivers an image circle of 1 arcsec from 400 to 750 nm.
- collimator - Edmund spherical mirror with 101.6 mm fl (203.2 mm radius)
- gratings - Edmund 25x25 mm, 600 and 1200 lpm and an Optometrics 25x50 mm 1800lpm
- collimator to camera angle - 38 degrees
- camera - 85 mm f1.8 Nikon lens (internal focus). Better than average resolution - got lucky!
- imager - QSI583 (5.4 um pixels)
Calibration source:
- Relco lamp behind a frosted aperture and motor driven into beam so as to illuminate the spectrograph identically to the telescope.

Weight of the spectrograph with the reducer guide and calibration assembly but without the imagers is 1.5 Kg

Originally I had some flexure problems that resulted in small orientation dependent wavelength shifts but these were
tracked down to flexure of the front face of the QSI 583 and movement at the camera lens mount. Both were solved.
With the 1800 lpm grating I have pushed this classical design to the limit. The 0.63 anamorphic factor results in a 14 um slit image on the CCD.
Focus is thus critical and I had to change the imager mounting to allow a precise tilt to be dialed in for each grating rotation.
I now have a table of tilts versus grating rotation that enables me to set this up quickly.

Tim

Re: CH Cyg at high resolution

Posted: Fri Jan 02, 2015 4:01 am
by Tim Lester
CH Cyg on Dec 28th - compared to my last two spectra.

Image

Tim

Re: CH Cyg at high resolution

Posted: Thu Mar 12, 2015 5:26 pm
by Francois Teyssier
H alpha CH Cyg 10-03-2015

eShel + SC 10" + ATIK 460EX
Traitement : ISIS
_chcyg_20150312_139_ha.png
_chcyg_20150312_139_ha.png (15.12 KiB) Viewed 16750 times
Comparison with Tim Lester's spectrum
CHCyg_Comp.png
CHCyg_Comp.png (19.23 KiB) Viewed 16749 times
Rappel : H alpha campaign for Augustin Skopal : at least 1 spectrum a month
Low resolution spectra are welcome

François Teyssier

Re: CH Cyg at high resolution

Posted: Wed Mar 25, 2015 6:51 pm
by Tim Lester
CH Cyg on 25-03-2015.
H alpha and H beta compared to Christian's last eShel spectrum on the 17th.
H alpha
H alpha
CH Cyg_Ha.png (6.6 KiB) Viewed 16693 times
H beta
H beta
CH Cyg_Hb.png (6.71 KiB) Viewed 16693 times
Tim

Re: CH Cyg at high resolution

Posted: Wed Mar 25, 2015 7:21 pm
by Francois Teyssier
Excellent !
The campaign begins well
There are several absorptions on the blue edge as your spectrum shows
CHCyg.png
CHCyg.png (15.58 KiB) Viewed 16690 times
Note : Augustin Skopal prefers that the spectra are corrected for heliocentric velocity
(I'll precise this point in the next letter)


François

Re: CH Cyg at high resolution

Posted: Tue Jun 30, 2015 10:00 pm
by Olivier GARDE
Another animation of CH Cyg : time serie of 64 exposures of 180s each (3H)

For Halpha
Image


For H Beta (see the small emission line near 4888 Â)
Image