POLARIMETER DEVICE PROJECT

[Joan Guarro Flo]

Hello,

In this picture, you can see a comparison of a polarimeter design and The-Maid polarimeter, also some prices of their optical components.

Regards, J. Guarro.

[Martin Dubs]

Hi Joan,

I have followed your polarimeter project with great interest. Looking at your newest Project, Maid, I noticed that you position the HWR after the slit. I do not think that this a good idea. According to vector theory of diffraction, a slit produces some amount of polarization (similar to the polarization effect of a linear grating or a wire grid polarizer). I could not estimate the size of the effect, my books on diffraction theory only give results for one polarization, so I do not know if this is a serious problem. However I strongly recommend to place the slit aftrer the halfwave plate, in order to eliminate possible effects of the slit polarization.

Clear skies,

Martin

[Joan Guarro Flo]

Hallo Martin,

Many thanks for your advice! I have just modified the drawing after reading your feedback.

The-Maid aim is try to get a range from 3700 to 8500 Angstroms, instead of the 4200 to 7550 The-Giver ones, and Thorlabs' AHWP10M-580 is an adequate Half-wave retarder, really the only one that I know.

A question for you, The-Giver has the Half-wave polymer retarder before the Alan Gee II Telekompresor, following the suggestions that Gary Cole gave
me during its design. Now, due to in fact an issue size, I put the Alan Gee II first in The-Maid drawing. What consequences do you think it would have?

Many thanks again, Joan.

[Joan Guarro Flo]

Hello,

Spectropolarimetry can show different particularities of every star throughout this wavelength range.
You can notice in Gam Cas the replicated H spectrum lines, also H Gamma, that don't appear in this
spectrum. Gam Cas polarization is rising from IR to UV.

This phenomenon is more evident in star Shelyak.

On the other hand, Pi Aqr doesn't have its H Alpha replicated.

It seems that all works well in The-Giver spectropolarimeter, as one can see in the standard non-polarized star Bet Cas.
Making tests from time to time is necessary.

Regards, J. Guarro.

[Joan Guarro Flo]

Hello,
Gerardo Ávila studied The-Maid design and found that the aspheric achromatic lens is not useful as a lens camera objective,as you can see in this image.  He proposes a photographic  100mm focal objective, but it requires changing the 600 l/mm  grating for another 300 one.

This has modified not only The-Maid's design if not that it has an incidence in its budget.

The-Giver L-R Spectropolarimeter is using a Nikon Noct 58mm f/1.2, the same as you can see in the SPOL
scheme. The alternative of a Nikon 105mm f/2.8 with a 300 l/mm grating could be a really good solution.

Regards, J.Guarro.

[Joan Guarro Flo]

Hello at all,

These are some of the last The-Giver L-R Spectropolarimeter.

These kind of observations give surprises sometimes similar as you can see in Saturn graphics.

The current and main difficulty is find some analyst that wants to work with them, give time to time...

Best regars, J. Guarro.