First Uvex3N5 tests

My Uvex was the last built in 3D of the first series of 5, like Stéphane’s, it has the Calibrex module entirely built in 3D as the main box (see photo above).

And the first tests on the sky allow to validate this set. The purpose of this module is to calibrate the spectrum using an internal neon lamp, flats and autoguiding on a slot.

My Uvex was not perfectly adjusted, probably today it remains perfectible, but good with good advice from Christian (see paragraph Uvex) it is done without much trouble.

My equipment astro a Vixen Fluo 90/810 mm scope, which makes an F / D ratio = 9, a good report for the Uvex. We will not go as much in the blue as a Newton telescope open at 10, but to take your first steps it is fine. We can already try the internal neon of the Calibrex module, once it is on (push button) a pose of 2 s is enough to make the spectrum. My CCD camera is an Atik 314+, and the neon was collected in an easy-to-find ballast starter in DIY stores. We can notice that the lines are wide, it is not ideal, it is that we do not have an F / D ratio of 9 in the Calibrex module. We are thinking of a solution by fiber to inject the neon light directly onto the spectro slot. Currently we have the neon which diffuses in the whole of the cavity of Calibrex module and a mask comes to be put in front of the neon by a servo motor to direct part of the light on the slit.

Second solution put the neon in front of the opening of the scope, the result is perfect the lines are clear (argon and neon) the pose is longer 30 s, do not forget to wave the neon in front of the lens. To make this external neon take the choke, open it to remove the capacity, and above all put a resistance of 24 Kohms – 1W in series on one of the two legs and all to be connected to the 220V. We can do this when we are near the house, as a nomad it is different.

Calibrex internal neon pose 2s
External neon pose 30s
External neon

Now let’s make a spectrum of a star, but before we have to put the target star in the slit, it must be vertical and make sure that the displacement of the right ascension of the instrument is perpendicular to the slit. It is enough to position the spectro at the focus and to turn the guide camera fixed on the Calibrex module, in order to have the vertical slot. My guide camera is a 120MM ASI therefore monochrome, very sensitive, and inexpensive. The field of this one is 12 ‘X 17’, I present to you an image of the field of the star EW Lac in the “mirror” comprising the slot. The resulting image is very satisfactory, I re-sized to have the star field and submit it to the Astrometry.net server to determine the limit magnitude. I find a magnitude of 13 which is very good for a 90 diameter scope. I use the PHD2 Guiding software which works very well for autoguiding.

On both sides of the field we see two circles, this corresponds to the fixing of the slit mirror.
Resizing the useful field.
Field recognition with Astrometry.net.
Fields on the C2A software.
25 microns slot lit in front of the tube, we can see it perfectly and as a bonus a star on the left.
Shelyak slot used for the Calibrex module, different widths are available.

Now visualize my first spectra, once the target in the slot and the autoguiding running. I’m not talking about the settings described by Christian, everything is very well explained in the “Uvex” paragraph. It is essential to have clear stars visible on the “mirror” slot and the spectrum science net too, the first session it was not the case, I had simply forgotten to focus the telescope! Do not forget also to make a reference spectrum, a neon for each star and also the offsets, and the darks. I use Isis which works very well and is scalable.


HD358 spectrum
HD193182
HD213470


The first HD358 spectrum is not very fine, a tuning of the chain solved the problem. It is a star of spectrum B8IV-VHgMn or can be calibrated on the Balmer lines.

The HD193182 spectrum is fine and clear, B7IV / V(e) Magnitude : 6.51
10 poses of 60 s achieves this result.

Finally some spectra profiles made with the same set up.

Spectra of the Be star 8 Lac A.
The star Be 8 Lac A is located below 8 Lac B
Another Be star: Ew Lac
The Be LQ And

My first comments on this new Uvex spectro designed by our friend Christian, a real gift offered to amateurs, once made in 3D a real working tool that can be changed over time. Currently I use a 300 rpm network with a 25 micron slot, and I work mainly in the visible, but tomorrow I can go with a network of 600 or 1200 rpm, work in the UV or the IR, the flexibility of the Uvex allows it Here are my first impressions, the strength of this spectro is the simplicity of use once well adjusted, and also the pleasure of using something that one has built itself, a real instrument 3D printed scientist …..