Bad efficiency of the eShel from shelyak

Design, construction, tuning of spectroscopes
Information and discussion about softwares (telescope remote, autoguiding, acquisition, spectral processing ...)

Bad efficiency of the eShel from shelyak

Postby Berthold Stober » Wed May 08, 2019 6:13 pm

Bonjour à tous

I have for some time ( perhaps the last 6 months) big problems with the efficiency of the shelyak eShel . I sent it to shelyak but no effect could realized. The bad efficiency is still to see. I have changed all fibers -> nothing. In 2015 I had with KAF 3200 after 10 seconds using the tungsten lamp oft the calibration unit about 50.000 ADU and now I have since about 6 months 50.000 too but I need now 25 seconds. I don't know what I could do to solve this problem.

The efficiency of an eShel is high depending of the correct amount of the angle alpha , 63 degree. How can I find out if this angle is correct on my eShel?

So how it is, I cannot use the expensive device.

Berthold
Berthold Stober
 
Posts: 26
Joined: Thu Apr 21, 2016 8:15 pm

Re: Bad efficiency of the eShel from shelyak

Postby James Foster » Wed Jun 12, 2019 9:47 pm

To: Berthold,

I don't have an eShel, but have you gone through Shelyak manual and Christian's extensive notes on how to set-up the
instrument and process data using Isis? Here are some links:

Shelyak Manual:
https://www.shelyak.com/wp-content/uploads/DC0009B-eShel-User-Guide1.pdf

Device use:
http://www.astrosurf.com/buil/echelle/first.htm
http://www.astrosurf.com/buil/eshel3/review.htm

Isis data processing:
http://www.astrosurf.com/buil/isis/eshel/tuto1.htm
http://www.astrosurf.com/buil/isis/eshel/reduction/echelle.htm
http://www.astrosurf.com/buil/isis/eshel_extended2/index.html


Remember, Spectroscopy is on the bleeding edge of what Amateur astronomers do and, as such, we must research techniques
and theory more than any other portion of amateur astronomy. The only harder pursuits in amateur astronomy maybe radio astronomy and/or
spectropolarimetry where you need both spectroscopic expertise and knowledge of magnetic-electrical fields to interrupt the data.

James

p.s. Once you get eShel running, remember that Shelyak has a modification for eShel that improves its near UV efficiency and increases the orders you
can get usable data from.
James Foster
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: 326
Joined: Sun Jan 24, 2016 7:14 am

Re: Bad efficiency of the eShel from shelyak

Postby Berthold Stober » Sat Nov 02, 2019 4:38 pm

tungsten190918-binning21_12_8norm.png
I tried to reduce those waves bei changing the "binning zone" in ISIS but nothing
Hello to all,

I found, that ISIS seems to create strange effects, visible by extracting a 2D flat_tungsten. Look the adnex please. If I extract the same flat with midas those "fringes" are not visible!
Could anyone tll me something about this phenomena?

cheers Berthold
Attachments
Flussschwankung_0.883.png
some enlargement
Berthold Stober
 
Posts: 26
Joined: Thu Apr 21, 2016 8:15 pm

Re: Bad efficiency of the eShel from shelyak

Postby Christian Buil » Sun Nov 03, 2019 11:17 pm

I suggest that you publish the aspect of the (2D) image of a typical tungsten spectrum and of a spectrum of the thorium-argon lamp.

I suspect that you work in 2x2 binning with your camera. That's right ? I's an Atik460EX model?

A screenshot of the "eShel tab" and the "eShel-> Setting tab" has also well come.

(Note also that using the calibration tungsten lamp is not the best way to evaluate the response of your spectrograph: result is depending, for example, on how the science fiber is illuminated by the light coming from the calibration fiber in the guidance module - did you realize this centering by observing with the guidance camera?).

Christian
Christian Buil
 
Posts: 1289
Joined: Mon Sep 26, 2011 6:59 pm

Re: Bad efficiency of the eShel from shelyak

Postby Berthold Stober » Thu Nov 07, 2019 6:23 pm

Thank you Christian for answering!

Yes I'll publish the tungsten und ThAr 2D !
No, I'm not using 2x2. binning , I use a KAF 3200 1x1 binning!

Yes I'll publish the setting file!

Ok, it could be that the light from the 200 mue fiber is not perfect centered over the pinhole, But!!!

I know a professional Astromer who reduced the SAME files with Midas and there is nothing to see from those "fringes" . Therefore It is nearly not possible that those phenomena are caused by my equipment.
This astronomer told me, that the "slit with" of the software is to small. One can change this slit with in Midas but not as fare I can see it is possible to change it in ISIS (?)

( I get no information via email if an answer is incoming here even if I have it switched on)

Cordialement et merci beaucoup
Berthold
Berthold Stober
 
Posts: 26
Joined: Thu Apr 21, 2016 8:15 pm

Re: Bad efficiency of the eShel from shelyak

Postby Berthold Stober » Thu Nov 07, 2019 7:39 pm

ISIS-settings.png


Hello Christian,

ok there are the files to see. I'll send you via wetransfer the files as 2D . They are to big, so I cannot upload them here.

Is it what you need?

If you need more informations please let ist know me.

Cordialement Berthold

(In the calibration unit I have a tungsten lamp with only 5 W. Therefore we have no much light in the higher orders. I have a special computed filter which allows me to have less enrgie in the red part and more in the blue part of orders. but this lamp is to week for this filter. Do you know if the calibration unit can tolerate higher power lamps?How many Watts are posible?)
Attachments
tungsten_30sec190918.png
ThAr_15sec_190918.png
Berthold Stober
 
Posts: 26
Joined: Thu Apr 21, 2016 8:15 pm

Re: Bad efficiency of the eShel from shelyak

Postby Christian Buil » Fri Nov 08, 2019 2:32 am

Thanks for the infos. For complete, capture and publish a screenshot of the main "Instrument - eShel" tab.

Christian
Christian Buil
 
Posts: 1289
Joined: Mon Sep 26, 2011 6:59 pm

Re: Bad efficiency of the eShel from shelyak

Postby Berthold Stober » Fri Nov 08, 2019 3:38 pm

Instrument_tab191108.png


Bonjour Christian,

voila l'image d'ecran. Est ce que ca suffit pour le moment? J'ai envoye les 2D frames via wetransfer.

Berthold
Berthold Stober
 
Posts: 26
Joined: Thu Apr 21, 2016 8:15 pm

Re: Bad efficiency of the eShel from shelyak

Postby Berthold Stober » Fri Nov 08, 2019 7:01 pm

Deneb191107_Na_fringes.png
those "fringes" are not ok
[attachment=0]

I would like to publish there the ".....full.fit" 1D but this seems to be impossible.

berthold
Berthold Stober
 
Posts: 26
Joined: Thu Apr 21, 2016 8:15 pm

Re: Bad efficiency of the eShel from shelyak

Postby Andrew Smith » Fri Nov 08, 2019 7:11 pm

Just some thoughts. Have you checked/cleaned the fibres? Do you shake the fibre to reduce modal noise. With my guide head I found misaligned calibration optics in the guide head I produced considerable modal noise.
Regards Andrew
Andrew Smith
 
Posts: 304
Joined: Fri Sep 30, 2011 12:23 pm

Next

Return to Spectroscopes and Softwares

Who is online

Users browsing this forum: Google [Bot] and 3 guests

x