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PostPosted: 29. September 2016, 18:50:22 PM 
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Hi Paul,

yes, they are expensive, but they work.

ciao,
Daniel

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PostPosted: 17. October 2016, 21:06:55 PM 
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I've registered my first spectrum with the LOWSPEC and I'm very pleased with the result. I'm using a very modest remote setup consisting of a 'Russentonne' (Maksutov) on a EQ6-Pro placed in a box on the kitchen roof...


Attachments:
vega-lowspec.jpg
vega-lowspec.jpg [ 106.68 KiB | Viewed 2712 times ]
File comment: My setup on the kitchen roof.
CIMG1392.JPG
CIMG1392.JPG [ 266.14 KiB | Viewed 2712 times ]
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PostPosted: 17. October 2016, 21:25:02 PM 
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Ausgezeichnet!

Berthold


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PostPosted: 17. October 2016, 21:45:59 PM 
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Cool stuff!!! :D Congratulations, Paul, for this success. I recommend to do various measurements at different targets to see the instrumental capability. And I would go for fainter stars for estimating the thresholds in S/N, R and exposure time. And I would estimate the achieved resolving power.
Cheers, Thomas


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PostPosted: 18. October 2016, 10:43:18 AM 
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Thanks for the compliments!
At the moment I'm waiting for an ALPY slit as the current slit (Lenox) is not reflective enough and the surface near the edge of the slit is dirty. Probably due to the laser that created the slit.
Also, the 25 micron slit is a bit to wide for this configuration (D=100mm, f=1000) so dim stars disappear into the slit. That is to be expected as I originally designed this instrument for my other telescope (203 mm f/8) which, for the foreseeing future, I cannot use.

Measurement of the calibration lines (Relco) give a resolving power of 900 in the vicinity of H-alpha but in the spectrum of Vega the two Sodium D lines are visible suggesting a resolution of about 6 Angstrom.

At the moment I’m using an ALPY calibration unit but the plan is to incorporate a calibration unit into the design. I have some difficulty with that as I don’t have any knowledge about electronic circuits. I’ve already asked for help in the small but growing Dutch spectro-community but I would appreciate advice from members of this forum.

Cheers,
Paul


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PostPosted: 03. November 2016, 21:39:24 PM 
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I've made some more modifications to the LOWSPEC design.
Focusing is a real pain. Moving the whole camera in and out on the roof is not fun. So I came up with this focusing mechnism to move the camera lens back and forth.
Also I installed a Alpy slit which replaces the Lenox slit in order to improve autoguiding.
Hoping for some clear skies to test this thing soon.


Attachments:
focuser2.jpg
focuser2.jpg [ 232.87 KiB | Viewed 2689 times ]
lowspec-3.jpg
lowspec-3.jpg [ 91.97 KiB | Viewed 2689 times ]
lowspec-4.jpg
lowspec-4.jpg [ 92.04 KiB | Viewed 2689 times ]
lowspec-1.jpg
lowspec-1.jpg [ 92.78 KiB | Viewed 2689 times ]
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PostPosted: 31. July 2017, 16:24:43 PM 
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I've place the 3D files of my LOWSPEC design on-line for everyone interested:

https://www.thingiverse.com/thing:2455390

Regards,
Paul


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PostPosted: 31. July 2017, 17:43:06 PM 
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Congratulation for this construction...

I just notice one problem with a 3D printer and spectrography, that's the plastic is transparent for Infrared wavelength, so you have to put some aluminium adhesive tape all around the spectrograph to prevent any pollution of your spectrum.

Have you an idea about the resolution of your spectrograph, the wavelength range and the efficiency ?


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PostPosted: 31. July 2017, 18:48:15 PM 
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Sehr gut, gut gemacht. Was würdest du verlangen für einen Nachdruck? Gehäuse und Fassungen?

Schöne Grüße
Berthold


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PostPosted: 13. August 2017, 20:52:24 PM 
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Quote:
Congratulation for this construction...

I just notice one problem with a 3D printer and spectrography, that's the plastic is transparent for Infrared wavelength, so you have to put some aluminium adhesive tape all around the spectrograph to prevent any pollution of your spectrum.

Have you an idea about the resolution of your spectrograph, the wavelength range and the efficiency ?
Thanks Olivier.
I did notice this in earlier test builds. I used PLA and did notice a 'haze' in the infrared part of the spectrum. My latest build was printed with ASA filament which apears to be opaque to infrared as far as i could see.
I only did a test with a Maksutov photo lens and the star image was smaller than the 25 micron slit I used at the time. The resolution was about R=900.

Regards,
Paul


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PostPosted: 24. November 2017, 21:49:50 PM 
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Hi,

ich habe den LOW SPEC jetzt soweit fertig, allerdings habe ich den Spalt selbst gemacht, der ist natürlich verbesserungsfähig.

Aber das erste Neonspektrum sieht leider seltsam aus und ich kann es nicht zum Eichen verwenden.

Vielleicht kann das jemand!?


Attachments:
File comment: Neonspectrum
171124Neon_10sec_m5,9_1D.fit [8.44 KiB]
Downloaded 66 times
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PostPosted: 24. November 2017, 23:00:25 PM 
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Hello Berthold,

That Neon spectrum does not look ok. It looks out of focus.
Did you check the alignment of the components with a laser? The 'big' mirror that reflects the light through the collimator can be adjusted with the three Allen grub screws.
I assume that you first collimated the collimator?

I've included a FIT of a Neon-Argon spectrum recorded with the LOWSPEC (with ALPY photometric slit).
Attachment:
Ref_Ne-Ar.fit [8.44 KiB]
Downloaded 58 times


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PostPosted: 02. April 2018, 22:21:59 PM 
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Hallo,

Spaltweite 20µm, KAF 1602. Soweit wäre der LOWSPEC jetzt einsatzbereit. Mal sehen, was dabei an Sternen herauskommt, im Neonbereich sind die Linien ja ganz schön scharf......im Blauen wird es schnell schlecht, auch ist dann die QE beim KAF 1602 nicht gut......Aber man kann hier schon sehen, dass der LOWSPEC ein netter Apparat ist:

Sehr leicht, sehr präzise und für das gebotene R auch bestimmt hinreichend steif.

Berthold


Attachments:
File comment: hier kann man die Kalibrierung nachvollziehen
neonkal_180402.png
neonkal_180402.png [ 161.7 KiB | Viewed 2590 times ]
File comment: Ergebnisse mit simspec
simspec_slit_Lowspec.xlsx [37.11 KiB]
Downloaded 57 times
File comment: Kalibriertes Neonspektrum mit dem lowspec
neon_180402_1D.fit [14.06 KiB]
Downloaded 55 times
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PostPosted: 03. April 2018, 17:54:34 PM 
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Hallo Berthold,
hast Du den Lowspec selbst gebaut oder gibt es jemanden, den man damit beauftragen kann?
Viele Grüße
Christian


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PostPosted: 04. April 2018, 19:29:34 PM 
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Quote:
hast Du den Lowspec selbst gebaut oder gibt es jemanden, den man damit beauftragen kann?
Berthold asked me to build one for him.


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PostPosted: 04. December 2018, 21:13:08 PM 
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Hallo,
ich habe heute von Paul den LOWSPEC erhalten. Er macht einen hervorragenden Eindruck. Ich muss nur noch die optischen Bauteile ergänzen. Die Bestellungen sind bereits raus und ich hoffe, daß ich bald zum Testen komme.
Viele Grüße
Christian


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PostPosted: 12. December 2018, 21:12:03 PM 
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Hallo,
ich habe inzwischen alle optischen Elemente bis auf den Spalt eingebaut. Der Spalt müsste auch bald bei mir eintrudeln. In der Graphik von Paul ist der optische Aufbau zu sehen.
Attachment:
optical-components-LOWSPEC.jpg
optical-components-LOWSPEC.jpg [ 50.9 KiB | Viewed 2272 times ]
Dabei sind zwei Elente zu justieren: First surface mirror (ganz oben) und der Achromat Thorlabs AC254-080-A. Der Rest kein Problem mehr. Das eigentliche Problem ist der Spiegel. Dazu habe ich mit folgende Methode überlegt, wobei ich Eure Meinung bzgl. Richtigkeit wissen will:

Ich zäume das gewissermaßen das Pferd von hinten auf, wobei ich die Tatsache nutze, daß ein monochromatischer Laserstrahl das Gitter als paralleles Bündel wieder verlässt.

1. Der Achromat AC254-080-A wird vorrübergehend entfernt.
2. Ein Laserpointer mit praktisch vollkommen parallelem und eng gebündelten Lichtstrahl wird auf die optische Achse des Teleskops gebracht und so justiert, daß er genau die Mitte des anderen Achromats (AC254-125-A) trifft. Dann stimmt zumindest die Ausrichtung des Spiegels.
3. Das Gitter wird so gedreht, daß der Laserstrahl das Gitter parallel zur optischen Achse des entfernten Achromaten verlässt.
4. Nun wird der Laserpointer im Abstand von 8 - 10 mm von der optischen Achse des vorrübergehend entfernten Achromats positioniert und zwar genau parallel zur Achse mit Richtung Gitter.
5. Der Laserpointer wird um die Achse des Achromaten rotiert, wobei die Ausrichtung immer ganau parallel zur Achse beibehalten werden muss.

Dabei wird ein heller Fleck auf der Rückseite des Spalts erzeugt. Der Spiegel wird mittels 3 Madenschrauben auf seiner optischen Achse hin und herbewegt bis der Fleck bei der Rotation stets an der selben Stelle bleibt. Dann ist der Spiegel optimal justiert.

Das klingt kompliziert und ist es wohl auch.
Frage: Ist meine Überlegung korrekt bzw gibt es eine einfachere oder bessere Möglichkeit?

Viele Grüße
Christian


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PostPosted: 05. January 2019, 00:42:46 AM 
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I've recently made some design changes to the LOWSPEC. The camera lens (25.4mm f=80mm) has been replaced with a 30mm f=100mm achromat. Also the grating holder has been changed a bit and has been fitted with a 1800l/mm grating.
Here's a quick daylight spectrum of the near infrared region. R=9500.

regards,
Paul


Attachments:
lowspec_daylight_O2-region.jpg
lowspec_daylight_O2-region.jpg [ 121.28 KiB | Viewed 2083 times ]
lowspec_daylight_O2-region_profile.jpg
lowspec_daylight_O2-region_profile.jpg [ 143.16 KiB | Viewed 2083 times ]
LowSpec 2.0.png
LowSpec 2.0.png [ 169.17 KiB | Viewed 2083 times ]
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PostPosted: 15. January 2019, 21:16:57 PM 
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Attachment:
Bildschirmfoto von 2019-01-15 19-43-20.png
Bildschirmfoto von 2019-01-15 19-43-20.png [ 57.11 KiB | Viewed 1956 times ]
Hello,
I had to wait a long time for the ovio slit but now I am ready to start with tests. I took several spectra of the day light with a 135 mm lens.
The lines of the 2d spectrum are tilted. This is probably caused why the grating is not in an upright position. There is a distance between the upper edge of the grating holder and the housing.
This indicates that I have still to improve the setting of the optimal elements.
Cheers
Christian


Attachments:
Bildschirmfoto von 2019-01-15 18-53-40.png
Bildschirmfoto von 2019-01-15 18-53-40.png [ 321.68 KiB | Viewed 1956 times ]
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PostPosted: 28. February 2019, 20:05:39 PM 
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alpCMi_20190227_teil.png
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Hallo,
gestern hatte ich zum ersten Mal Gelegenheit, ein Sternspektrum aufzunehmen und zwar Castor. Das Guiding musste mit der Hand erledigt werden, da PHD2 einfach keinen Rahmen um das Objekt legen wollte. Bei einer Belichtungszeit von 3 s ist dies allerdings verschmerzbar. Mir ist allerdings unklar, ob dies am Lowspec oder an der Gemini 2 Steuerung liegt, die ich seit neuestem einsetze, da meine alte Photo Elegance nur noch teilweise funktioniert.
Viele Grüße


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PostPosted: 08. September 2019, 14:52:53 PM 
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Hallo,

first of all, thank you Paul, for publishing your design of the LowSpec and the ongoing improvements you are working on. This enabled me to sidekick a second project to build another spectrograph, while I was on my way building the Minispec, which is now nearly finished as well.

But basically with your design I was able to get my first spectrograph finished within something about 3 months. As my own 3D printer is not good enough quality for such project, I found a service provider that was printing the components for me and delivered withing 2-3 weeks with good enough quality. At the same time I was ordering all other necessary components and the final assembly, even doing it slowly and rather carefully, was only about 2 weeks. So now I am as well part of the LowSpec user community.

Der Grundaufbau erfolgte erst einmal mit dem 300 Linien Gitter, aber ein 1800er liegt schon bereit. Beide können auch alternativ im Minispec verwendet werden.
Spektren und Analysen werden hoffentlich bald dann von astronomischen Objekten folgen.

Viele Grüße
Juergen


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PostPosted: 06. October 2019, 06:53:49 AM 
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Paul,
As you know others have made use of the OVIO multi reflective slit plate........

It would be interesting to hear from others who have built 3D printed spectrographs, and see the actual results being obtained.
Ken

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