Forum der Vereinigung der Sternfreunde

Hello to all,
After a lot of time I returned here, I apologize to you for that.

Sure you know the Tim Lester echelle spectrograph, you can see it here.
http://www.spectro-aras.com/forum/viewt ... 4a287fbbdc

It is a really nice and elegant and very effective design solution, without optical fiber, it pleased me and I made one with very good results. 

Then I told Tim the possibility to make some of them for possible observers that can't afford commercial echelles. Tim answered me " OK, but with the most possible cheaper price ".

I have made a little series of these echelle which one cost € 3000 without the optical parts ones which cost around € 1000. Obviously they have Relco and tungsten lights.

I show here some photos about this echelle, the NOU_T. NOU is NEW or NINE or NUT in Catalan language and the T is for Tim.

If you want more information, please let me know. I will try to show more results in the future here.

Best regards, J. Guarro.

Hello:

You can see another amelioration sample with using the Sony IMX571 CMOS Monochrome Sensor,
( in this case a camera ASI2600MM ).

Cheers, J. Guarro.

Oh thank you.

where could I get the parts and so for this echelle?

Cheers
Berthold

Hello Berthold,

At this moment I have available two NOU_T echelle, only missing anodize in black their pieces.

I could send to you one a month from now, or approximately two months if you would want one of them with the optic mounted.

If you are interested in it, please leave me a private message in this Forum and I will get in touch with you.

Remember that you could improve your eShel too.., and for very good results in both cases you need an ASI2600MM..

Cheers, Joan.

Hi Berthold,

I would tell you some opinions and things.

It seems that the ASI2600MM is better than ASI1600mmpro.
If I haven't made any mistake :

ASI1600  size 17.7x13.4,  pixels 4656x3520, 3.8x3.8 microns   20000 e-  14B
ASI2600  size 23.5x15.7,  pixels 6248x4176, 3.76x3.76 micr.    50000 e-  16B

But that is not the most important thing at the moment.

If I were you, I would improve your eShel step by step, Shelyak buys a new nice achromatic collimator doublet that takes out the residual achromatic aberration.

The second step is to know the origin of your echelle grating, you know Tobias Feger's report very well. On the other hand I'm waiting for an Optometrics  one, then we will see. If it doesn't work I'm going to buy a Richardson one.

Then make a new check with your Canon 85mm. f1.8 and your ASI1600MMpro. I'm
sure that the new uncomes improve and you reach some order more in your graphic.

What do you think?

Regards, Joan.

Hi again Berthold,

In one message you said that you use and octogonal fiber, I don't know anything about that, but the fiber is a very important,
element in your type of echelle, so I think that you should C.Buil's trip in that issue, he talks about it in his report, and sure that he is right and I think you could change the optical fiber too.

Cheers, Joan.

Hi Joan
Many thank’s for your recommendations. Yes the chip of Asi1600 is even smaller
comparing asi2600 , so it becomes to expensive for me with a direct linked Echelle.

At time I have with KAF 3200 30000 ADU (0,9e/ADU) taking 20 seconds Vega…
What do you get?
The octogonale fibers are more efficient then the non octogonale.

Do you mean that a grating from Richardson is more effective then this from shelyak.perhaps could Tobias Feger tell me somethings about this.

Cheers and thank you again
Berthold

Hi Berthold,

Personally, I think that for the improvement of your eShel, and according that C.Buil says in his report the ASI1600MMpro is the camera that you should use, because its slow read noise is useful for detect and keep the low signal that have our "modest" telescopes.

You only need to be safe of the spectral response of your octogonal fiber, and of courseyou would need  two scramblers to reduce the modal noise.

We only know that the Richarson echelle gratings are better than the Thorlabs, but I thinkthat you don't have the origin of your echelle grating, is it Ricahson ?Is it Optometrics ?Is it Thorlabs ? You could ask for it from Shelyak.

I put my hands on my head, when I was reading Tobias' report, because I have always bought Thorlabs the Echelle gratings, ( I didn't want to hear my possible sixth sense that told me my echelles didn't have much sensitives ).

Three months ago I bought an echelle grating by Optometrics and put it into a NOU_T that I sent to one observer. Of course I tested the echelle and noted that its exposure times have halved. 

I have bought another Optometrics one, its delivery time is 10th August, we're going to wait for that and know if the light difference that I noticed is true.Recently I have found that on the internet, https://www.edmundoptics.com/f/richards ... ngs/39690/, so the game is open.

Best regards, Joan.

Hello everybody,

Mounting a NOU_T echelle for an observer I have been the occasion to test his ASI 294MM camera with initialamazing and really good results, of course with daylight only.

The camera is more sensitive than de ASI 2600MM, overall in the red region, and taking integrations in its originalbinning 1x1, it is possible aplicate the advantages that ISIS offered in its CMOS image reduction, that is essentialon the time to take advantage of this information with a low levels of noise in binning 3x3, - 6.95 x 6.95 microns.

I am really glad, because now we can dispose of an echelle and a camera affordables.

J. Guarro.