Bad efficiency of the eShel from shelyak

Design, construction, tuning of spectroscopes
Information and discussion about softwares (telescope remote, autoguiding, acquisition, spectral processing ...)
Berthold Stober
Posts: 35
Joined: Thu Apr 21, 2016 8:15 pm

Re: Bad efficiency of the eShel from shelyak

Post by Berthold Stober »

There was used the same files for both reductions . left = ISIS right = midas
There was used the same files for both reductions . left = ISIS right = midas
Thank you for your answer but please look the adnex. It seems quite obviously that ISIS produces those "fringes" and it destroy so my spectra. It' rather clear that it is not caused by hardware problems.
I am not at all happy about this, I would prefer to go on with ISIS since Midas is not so easy to use.........but at the moment I have no choice!
Olivier GARDE
Posts: 1243
Joined: Thu Sep 29, 2011 6:35 am
Location: Rhône Alpes FRANCE
Contact:

Re: Bad efficiency of the eShel from shelyak

Post by Olivier GARDE »

Hi Berthold,

In the screenshot of the ISIS main page, you checked:
- Sum before
- Median Filter
- Function de blaze lissé

When I process my eshel spectra (with an ATIK 460ex CCD), I check only :
- Optimal Binning
- Cosmic Rays filters

Do you use a CMOS camera ?

Christian wrote a page that explains the checkboxes
http://www.astrosurf.com/buil/isis/eshe ... index.html
LHIRES III #5, LISA, e-Shel, C14, RC400 Astrosib, AP1600
http://o.garde.free.fr/astro/Spectro1/Bienvenue.html
Berthold Stober
Posts: 35
Joined: Thu Apr 21, 2016 8:15 pm

Re: Bad efficiency of the eShel from shelyak

Post by Berthold Stober »

The same files reduced with ISIS (left!) and midas (right)
The same files reduced with ISIS (left!) and midas (right)
James Foster
Posts: 439
Joined: Sun Jan 24, 2016 7:14 am

Re: Bad efficiency of the eShel from shelyak

Post by James Foster »

To: Berthold,

Christian gave a lot of great advice.....I don't have an eShel myself (as mentioned earlier) but I notice you have a Kaf3200 sensor which may not be optimal for
the eShel. I used this same sensor for my old L-200, and I got a ripple effect; abiet without using flats which were not part of that device, unlike Alpy600, LISA,
or LhiresIII. Since I acquired the Atik line of cameras for my Shelyak line of spectroscopes, this problem has gone away; sold my old L-200 last year.

Christian wrote this article on thew advantages using the Atik460ex with eShel: http://www.astrosurf.com/buil/eshel4/eval_en.htm

James
James Foster
eShel2-Zwo ASI6200MM Pro
Lhires III (2400/1800/600 ln/mm Grat) Spectroscope
LISA IR/Visual Spectroscope (IR Configured)
Alpy 200/600 with Guide/Calibration modules and Photometric slit
Star Analyzer 200
Christian Buil
Posts: 1431
Joined: Mon Sep 26, 2011 6:59 pm
Contact:

Re: Bad efficiency of the eShel from shelyak

Post by Christian Buil »

Hi Berthold,

Unselect the option "Median filter" and compare. The problem is here, I suspect.

The median filtering option is only for very well sampled spectral (typically eShel spectra taken by using small pixels CMOS camera).

Christian
Berthold Stober
Posts: 35
Joined: Thu Apr 21, 2016 8:15 pm

Re: Bad efficiency of the eShel from shelyak

Post by Berthold Stober »

no "waves" are to be seen in the continuum!
no "waves" are to be seen in the continuum!
Artefacts caused by ISIS
Artefacts caused by ISIS
The problem is obviously even I used "optimal binning" in ISIIS.

berthold
etienne bertrand
Posts: 1040
Joined: Mon Aug 31, 2015 11:26 am

Re: Bad efficiency of the eShel from shelyak

Post by etienne bertrand »

Possible "cosmic rays filter" if the spectr is very short ?
Berthold Stober
Posts: 35
Joined: Thu Apr 21, 2016 8:15 pm

Re: Bad efficiency of the eShel from shelyak

Post by Berthold Stober »

Hello,

I have had an ATIK 460ex to avoid those ripples. No effect. The same probleme was to see as demonstrated with the 460ex! That is not caused by the detector! Please see the results with MIDAS!

berthold
Berthold Stober
Posts: 35
Joined: Thu Apr 21, 2016 8:15 pm

Re: Bad efficiency of the eShel from shelyak

Post by Berthold Stober »

Deneb191107 with ISIS.png
Deneb191107 with ISIS.png
Deneb191107 with ISIS.png
No, it is the same with ISIS
there must be a problem with ISIS
unfortunately I can't send *.xml
that's not a probleme of the hardware.

berthold
Berthold Stober
Posts: 35
Joined: Thu Apr 21, 2016 8:15 pm

Re: Bad efficiency of the eShel from shelyak

Post by Berthold Stober »

Hi,

I overlooked the message of Christian, I don’t know why. Please excuse me.

Martin Dubs pointed this out to me once more, not to use the “median filtering” .What I don’t understand: I used at time CMOS detectors, but it was the same.

Berthold
Post Reply