eShel problem with V6.0.0

eShel problem with V6.0.0

Postby Bernard Heathcote » Sun Oct 04, 2020 8:55 am

I believe there is a bug in V6.0.0 affecting eShel spectra.

Using the same data and parameters the final spectra produced by V6.0.0. have many absorption spikes which are not present in V5.9.6 or earlier versions.
See attached example.

I have not check if a similar problem exists when reducing single order spectra.
Attachments
Ha compared.jpg
Full compared.jpg
Bernard Heathcote
 
Posts: 57
Joined: Mon Sep 26, 2011 10:09 am

Re: eShel problem with V6.0.0

Postby Christian Buil » Tue Oct 06, 2020 1:14 am

Look the eShel setting panel and adjust the Rejection coefficient to 100 (at the Botton of the panel, "Optimal extraction" section). Try also a zero value gain.

Christian
Christian Buil
 
Posts: 1397
Joined: Mon Sep 26, 2011 6:59 pm

Re: eShel problem with V6.0.0

Postby Bernard Heathcote » Tue Oct 06, 2020 8:46 am

Christian,

Thanks for your suggestion to change the Rejection Coefficient to 1000 as this did work. I also tested with the value 10, which also worked, compared to the original value 3 which did not work.

I am puzzled about what has changed between version 5.9.6 and 6.0.0 as the rejection coefficient=3 works with the earlier version but not with 6.0.0 (both using same data and xml files).

Cheers,
Bernard
Bernard Heathcote
 
Posts: 57
Joined: Mon Sep 26, 2011 10:09 am

Re: eShel problem with V6.0.0

Postby Bernard Heathcote » Tue Oct 06, 2020 9:23 am

Christian,

I have just noticed that one difference between V5.9.6 and V6.0.0 is that in the latest version the 'optimal extraction' setup has an entry for camera RON, which is not in V5.9.6.
As my QHY22 camera has a RON=5.0 I used that value (default =1.7) but that did not remove the noise. I assume there must be some other difference between the two versions on how optimal extraction is implemented.

Bernard
Bernard Heathcote
 
Posts: 57
Joined: Mon Sep 26, 2011 10:09 am

Re: eShel problem with V6.0.0

Postby James Foster » Tue Oct 06, 2020 11:53 am

Nice discussion on the eShel! I'm still trying to figure out my DEF_ORDER. LST file. One confusing thing I notice is
when Isis displays the 2d .fits image, it displays it with a vertical mirror image; I noticed this with Alpy and LISA processing previously.
Hopefully I'll be able to process my 1st eShel spectrum before Halloween......maybe!

James
James Foster
eShel2
Lhires III (2400/1800/600 ln/mm Grat) Spectroscope,
LISA IR/Visual Spectroscope (IR Configured Presently)
Alpy 600 with Guide/Calibration modules and Photometric slit
Star Analyzer 200
James Foster
 
Posts: 411
Joined: Sun Jan 24, 2016 7:14 am


Return to Software ISIS

Who is online

Users browsing this forum: No registered users and 1 guest

x