First starlight for my new echelle

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

Re: First starlight for my new echelle

Postby Michel Verlinden » Sat Apr 17, 2021 3:00 pm

Hello to all,

Great news Joan ! I'm very curious to see the results with an optical fiber.
Would you tell us what kind of fiber you use ?
Is it a model with a silica core and high OH like this : https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=6838 ?

Regards,
Michel Verlinden
Michel Verlinden
 
Posts: 185
Joined: Tue Aug 16, 2016 12:11 am

Re: First starlight for my new echelle

Postby Joan Guarro Flo » Sun Apr 18, 2021 2:49 pm

Bonjour Michel,

At the moment I'm going to use the optical fiber that I used with the Mussol and Linx echelles, first I need to mount the optical elements, ( June, July? ), when all will be tested I'm going to seewhat is the best.

I believe that the interest for the echelle spectrographs will come back, it is possible that the first handicap is the price, but there are solutions for it. This is a background race, in the meantime we need to put our eyes on this C.Buil's job, http://www.astrosurf.com/buil/asi6200mm/ , ( I think that we don't need to change our SC telescopes, sure the Newton ones are better, but we have what we have ).

We have one path to follow, and among other things we can deduce that our ATIKs or similar CCDs are a bit outdated. The new cameras are heavier and the weight is a persuasive reason in favor of the new NOU_T version.

Bien cordialement, Joan.
Joan Guarro Flo
 
Posts: 445
Joined: Thu Nov 03, 2011 8:50 pm

Re: First starlight for my new echelle

Postby Joan Guarro Flo » Mon Aug 16, 2021 5:28 pm

Hello at all,
You Know that Thorlabs is a serious  brand of optical components and almost all of us have used their products for our spectrographs. I have used too their echelle gratings for all my echelles, MUSSOL, LINX and the two NOU_T that I'm using now, each in Pieraother in Santa Maria, (SMM).

Last February/March, I read in FVDS one topic over "Efficiency  of Thorlabs echelle gratings", started by Tobias Feger on 23th October 2015, lord! Because I didn't read it before !! It seems echelle gratings from Thorlabs are really the most precarious ones in the world.

https://forum.vdsastro.de/viewtopic.php?f=2&t=4371

Years ago I sometimes bought gratings from Optometrics, so I bought them an echelle grating, and two months ago I mounted it in a NOU_T that I sended to an observer.

Of course, before I tested the NOU_T and noticed the Optometrics EC was twice more efficient than Thorlabs one ! Using a ATIK460EX  18000e-/pixel.

So I bought another one from Optometrics but I have waited one month for it because they are out of stock. Finally I tested this last Optometrics Echelle Grating in the PieraNOU_T with the ASI2600MM 50000e-/pixel, the efficiency is around 50%, similar as thefirst test.

But the behavior of both Optometrics EG there are different, the blaze angle isn't the same, so the RELCO ( tungstene ) points map is displaced.

The latest news is that Edmund Optics has started to sell Richardson EG, I'm going to buy one for the SMM NOU_T and I will see if Optometrics and Richardson have similar efficiency results.

You can see this Vega Graph, observation made between clouds and dust.

Cheers, J. Guarro.
Attachments
vega..png
vega..png (21.91 KiB) Viewed 1197 times
Joan Guarro Flo
 
Posts: 445
Joined: Thu Nov 03, 2011 8:50 pm

Re: First starlight for my new echelle

Postby Olivier GARDE » Tue Aug 17, 2021 7:18 am

Hi Joan,

Look at this book :
https://www.researchgate.net/profile/Ch ... dition.pdf

and you will have all the answers to your questions.
LHIRES III #5, LISA, e-Shel, C14, RC400 Astrosib, AP1600
http://o.garde.free.fr/astro/Spectro1/Bienvenue.html
Olivier GARDE
 
Posts: 1150
Joined: Thu Sep 29, 2011 6:35 am
Location: Rhône Alpes FRANCE

Re: First starlight for my new echelle

Postby Joan Guarro Flo » Tue Aug 17, 2021 9:45 am

Bonjour Olivier,

Many thanks for your interesting advices, I will try to understand that they explain. But in my humble opinion, the matter is, which is the best Echelle Grating, the Optometrics or the Richardson one ? We know now, according theoric studies and the practice Thorlabs Echelle Gratings are always below quality standards. I bought four of theses last ones so I have been wrong four times. Of course, I've also been wrong a lot of times in other issues..

Amitiés, Joan.
Joan Guarro Flo
 
Posts: 445
Joined: Thu Nov 03, 2011 8:50 pm

Re: First starlight for my new echelle

Postby Joan Guarro Flo » Sun Aug 29, 2021 11:54 am

Hello at all:

Finally I have been able to test my Richardson grating with Vega. Almost all of us use this generous star to test our devices.

The Richardson EG hasn't disappointed its expectatives, it is around 50% better than the Optometrics one, and Optometrics is also around 50% better than Thorlalbs one so the Richardson is the best of the them with an efficiency  100% over Thorlabs EG.

Unfortunately I don't have quantitative data about that. I only expose here my observational results based on the detectivity and exposure times with the same telescope, NOU_T echelle and ASI2600MM camera.

But all it seems to indicate is that with the Richardson echelle grating my telescope mirror  has twice the area than the Thorlabs one. In other words, my 40 cm. diameter virtually has passed at 55 cm.

Of course, without account the notable improvement is the change of the ATIK460EX to the ASI2600MM.

J.Guarro.
Attachments
VEGA+RIC.png
VEGA+RIC.png (18.97 KiB) Viewed 973 times
Joan Guarro Flo
 
Posts: 445
Joined: Thu Nov 03, 2011 8:50 pm

Re: First starlight for my new echelle

Postby Michel Verlinden » Sat Sep 04, 2021 9:10 am

Bonjour,
J'ai suivi de près les avancées du spectrographe NouT réalisés par Joan Guarro depuis presque un an. Au regard des tests présentés par Joan, j'ai décidé de le rejoindre dans sa démarche, avec l'idée d'apprendre le fonctionnement d'un spectrographe echelle, et d'aider humblement à l'amélioration de protocoles de réglage.
Je n'ai pas été deçu. L'instument est robuste (métal), stable thermiquement et les pièces mécaniques du NouT s'agencent parfaitement lors du montage. Joan m'a fourni une documentation pour le montage et les protocoles de réglage, et il m'a aussi beaucoup aidé par messagerie, faisant preuve d'une patience rare, un grand merci à lui. Les procédures de collimation ont été suivies et optimisées grâce à l'usage d'une caméra... Désormais, l'instrument est de mon point de vue assez simple à régler, mais m'a demandé un peu de temps au début (ce qui n'est pas vraiment une surprise lorsqu'on découvre).
Joan améliore constamment le NouT, actuellement il l'a modifié pour remplacer la caméra dédiée (une Atik460EX) par une ASI2600, vous avez du voir dans les précédents post l'élargissement du champs que cela permet et la récupération de plusieurs ordres dans l'UV et le NIR. Le changement du réseau (Richardson à la place de Thorlabs) lui a permis de gagner en rendement. Tous ces progrès sont spectaculaires et prometteurs.

Hello,
I have closely followed the advances of the NouT spectrograph made by Joan Guarro for almost a year. In view of the tests presented by Joan, I decided to join him in his approach, with the idea of ​​learning the operation of an echelle spectrograph, and humbly helping to improve tuning protocols.
I was not deceived. The instrument is robust (metal), thermally stable and the mechanical parts of the NouT fit together perfectly during assembly. Joan provided me with documentation for the assembly and tuning protocols, and he also helped me a lot by messaging, showing rare patience, a big Thank You to him. The collimation procedures were followed and optimized thanks to the use of a camera ... From my point of view, the instrument is now quite simple to adjust, but took a little time at the beginning (this which is not really a surprise when you discover).
Joan is constantly improving the NouT, currently he modified it to replace - the dedicated camera (an Atik460EX) by another, a zwo ASI2600, you must have seen that in the previous posts the widening of the captured field as a consequence, and the recovery of more orders in the UV and NIR. The change of the grating (Richardson instead of Thorlabs) allowed it to gain in efficiency. All of these advances are spectacular and promising.
Here are some images and plots obtained on the table, the target is the sky.

Voici quelques images et plots obtenus sur table, la cible est le ciel.
Ordres 25 à 57 non fusionnés:
sky_20210830_557_Michel Verlinden_full.png

Zoom sur quelques ordres :
sky_20210830_557_Michel Verlinden CaII.png

sky_20210830_557_Michel Verlinden Mg triplet.png

sky_20210830_557_Michel Verlinden O2_H20 atm.png

sky_20210830_557_Michel Verlinden CaII_NIR.png

Ordres fusionnés :
whitesky_20210830.jpg

Un spectre de test d'Elodie sur le ciel et mon spectre du ciel avec prise en compte de la réponse instrumentale:
sun_echelle NouT vs Elodie R8500_vs-42000.png

Tests avec Isis : angle de caméra, détection des ordres et positions des raies d'une lampe Relco SC480:
check2.jpg

RMS des ordres de calibration :
RMS.png
RMS.png (10.01 KiB) Viewed 805 times

Pouvoir de résolution mesuré dans chaque ordre (la mise au point est dans ce test effectuée sur des ordres excentrés, ce qui explique une moins bonne résolution dans les autres. Une moyenne arithmétique me donne R = 8500. J'ai aussi fait des tests en optimisant la mise au point sur les ordres centraux, je ne montre pas ici).
Resolution_NouT.png
Resolution_NouT.png (17.28 KiB) Viewed 805 times
.
Ce spectro echelle est une belle surprise par l'étendue spectrale couverte, résultat de choix matériels et de minutieux et patients efforts. Bravo Joan.
Michel Verlinden
Michel Verlinden
 
Posts: 185
Joined: Tue Aug 16, 2016 12:11 am

Re: First starlight for my new echelle

Postby Michel Verlinden » Sun Sep 05, 2021 4:38 pm

Je complète ici le premier test (effectué avec une Atik460EX), avec une vérification graphique de la calibration en longueur d'onde.
Pris à deux dates différentes, mon spectre du ciel et celui de l'OHP ont été corrigés de la vitesse radiale héliocentrique.
Vers 4000 A :
calibration_blue.png

Vers 5100 A :
calibration_green.png

Autour de 5500A
calibration_green2.png

Autour de Halpha :
calibration_red.png

Michel Verlinden
Michel Verlinden
 
Posts: 185
Joined: Tue Aug 16, 2016 12:11 am

Re: First starlight for my new echelle

Postby Joan Guarro Flo » Mon Sep 06, 2021 10:07 am

Bonjour Michel, comment ça va?

Many thanks for your generous treatment of me. I've always tried don't to disappoint you and don't betray your trust.
.
Your explanations and graphics are very nice and I think that you can test your NouT on the sky, I'm looking forward to it.

On the other hand, I'm really glad, because you were an entry in this, for you, unknown and mysterious world of echelle optical components. You have seen, it is easy, you only need a bit of patience and a bit of care.

Your job has broken all the myths around echelle spectrograph difficulties and with your new and useful collimation system I really consider you an expert.

Merci pour tout, Joan.
Joan Guarro Flo
 
Posts: 445
Joined: Thu Nov 03, 2011 8:50 pm

Previous

Return to Spectroscopes and Softwares

Who is online

Users browsing this forum: No registered users and 9 guests

x