NEW NOU_T ECHELLE RESULTS

[Joan Guarro Flo]

Hello,

Today I show a new way, a graphics star spectra and its V photometry by the Piera Observatory, take it is really, really easy, and a good system for obtaining complementary and interesting information very useful for astrophysics analysts.

Best regards, Joan Guarro.

[Joan Guarro Flo]

Hello,

Following the way to obtain joint information about star observations, such as spectroscopy plus a reliable and fine photometry, I can show you here, ( I think ), the first good results from Piera observatory.

From my point of view, these results can improve, because in this case only would lack sufficient integration time.

You can notice the remarkable stars defocusing.

In Piera and SMM observatories, the goal would be take good spectroscopy and V photometry from 1 to 12 star magnitudes, but for stars as Gam Cas,
( 2.18 V ), to VV Cep, ( 5.18 V ), is a bit difficult but not impossible.

You can see, in my humble opinion, we would explore new ways over all if they are useful.

Cheers, J. Guarro.

[Joan Guarro Flo]

Hello ,

Definitely, if you have a photographic objective and a CCD camera that you don't use, you could make very useful photometry while you're taking spectrography, these pictures are speaking for themselves.

You can see VV Cep results with 1.3 precision centesimas.It's a pity that I 've started the VV Cep's photometry a bit late in Ernst's campaign.

Best Wishes, J. Guarro.

[Joan Guarro Flo]

Hello,

You can see here another sample of another joint spectroscopic and photometric
observation in this case the symbiotic star CI Cyg.

The good comportement of the NOU_T echelle spectrograph there is added to the very nice photometric measurements now.

You know the NOU_T is a really available version based on Tim Lester's prototype and you can see it's a very agile and cheaper echelle.

For photometry beneath to hundredth V magnitude I've prepared a series of old Nikon
and Asahi-Pentax photographic objectives from 35, 50, 85, 105, 135, 150, 200 and 300mm. focal for Piera and SMM observatories.

With this equipment I can do spectroscopic observations R = 9000, with really a little noise, from 3710 to 9360 Angstroms and under hundredth photometry at the same time at stars from 1 to 12 V magnitude. Some analysts were interessested in these data for next star studies.

I would encourage you to take more advantage of your observational time and take
photometry data, it's really, really easy.

Cheers, Joan Guarro.

[Joan Guarro Flo]

Hello,

Following the current VV Cep observation conducted by Ernst Pollmann I've taken advantage of it for testing Piera and SMM little photometric equipements.

The aim was to construe their viability results, really the physical difference between them both is minuscule but sufficient to ruin my hopenesses.

So Piera equipment is now an ASAHI-PENTAX TAKUMAR 85mm. f/1.8, - 6 lenses -, closed to f/4 + BAADER BESSEL V-FILTER + an ATIK 460EX, defocused around 34 pixels and 120 seconds exposure time.

The SMM equipment difference is, an ASAHI-PENTAX TAKUMAR 105mm. f/2.8, -5 lenses-, closed to f/4, defocused around 44 pixels with 135 seconds exposure time.

Making the average of their both16 measurements I've found a difference of only 2 thousandths magnitude !!

That first result is very encourageous for bright stars V photometry using modest photographic objectives at the same time that we are taking the spectrographic observations. Of course I'm going to take more tests in this way that can confirm this first outcome.

Cheers, J. Guarro.

[Francois Teyssier]

Dear Joan,

A new great step for your setups!
High quality results. The outoff focus technics is very interesting.
It will allow to flux calibrate the spectra. The must.

I suggest time series of T CrB (one the few symbiotics which shows flichering at minutes time scale)

What are the current cameras (CCD or CMOS) at lower price than ATIK460EX which could provide good results in photometry?

All the best,
François

[Joan Guarro Flo]

Bonjour François,

Many thanks for your encouraging words, those techniques were used successfully in the past for photometry with telescopes and over all for
little refractors by GEA, - Grup d'Estudis Astronòmics, disappeared today -, with the legendary AUDINE ccd as a detector.

In my opinion, and comparing the size of the sensible surface of the two ATIK 460EX that I'm using, I think the similar CMOS could be:

CAMERA SURFACE (mm.) PIXEL e- CHARGE BINNING
ATIK 460EX 12.48 x 9.98 4.54 x 4.54 18000 1 x 1
ASI183MMPro 13.20 x 8.80 2.40 x 2.40 15000 2 x 2 ( 4.8 x 4.8 e- = 60000 )
ASI294MMPro 19.10 x 13.00 4.63 x 4.63 66000 1 x 1
ASI1600MMPro 17.70 x 13.40 3.80 x 3.80 54000 1 x 1

You can find some of these second hand cameras at, https://www.astrobuysell.com/uk/propvie ... rt=id+DESC.

It's possible the greatest CMOS capacity would be able to easily do more exact measurements, also the owners of these ASI cameras without cooling know how their performances are in exposures between 120 to 500 seconds time. Howerer, I'm very glad with the ATIK 460EX results.

The matter is : never low of 120 sec. exposure time, better 150 sec., it permits attenuate the atmospheric scintillation effects and spreading
the light stars in circular shapes with a good number of pixels, that their integration light permits high precision magnitude measurements.

It's important that over 65535 grey/levels, the star to study has a more charged pixel between 30000 to 42000 g/l, and 22000 to 50000 g/l.,
for the comparison stars, of course you can review it in the practice and results. Control all of this and take their integrations is very easy with
MaximsDL. The diaphragm objective is useful for that, with the advantage that we use the best optical zone avoiding possible aberrations of
the field surface edge.

Playing a bit well on our cards we could make Betelgeuse photometry with a 35mm. objective with an ATIK 460EX, integrating in the pictures the all brightly Orion stars including Rigel too, or made the same with a 50mm. objective with an ASI1600MMPro.

There wouldn't be any problem making T CrB with SMM ASAHI-PENTAX 300mm. objective, -16 images of 300 seconds everyone -, we could do it meanwhile we would make 6 spectrographic 1200 sec. exposure, I'll go put on the ATIK 460EX next weekend. How long do T CrB magnitude fluctuations last ?

Recently we see in VV Cep that spectroscopic and photometric values didn't necessarily have any exact coincidence. I left here a photometric observations graphic.

About the software for data reduction I would rather talk about it next time.

Amitiés, Joan.

[Joan Guarro Flo]

Hello,

These pictures show another simultaneous spectroscopic and photometric observation, in this case the symbiotic star AG Peg

You can judge for yourself their quality  level.  You could reach them, you could do the same.

Best regards, J.Guarro.

[Joan Guarro Flo]

Hello at all,

You can see here another example of the utility of simultaneous spectroscopy and photometry, this time is Gam Cas.

I would encourage you to do that, if it's possible, because it's a good way to take advantage of your time and achieve
supplementary and complementary information.

Also you can notice the high V photometry precision level .

Cheers, J. Guarro.

[Joan Guarro Flo]

Hello to everybody,

You can see here another good example of one result of Tom Lester's cheaper echelle design that hasn't been surpassed by anyone yet. That is complemented with a short photometric in V observation, with a photographic 300mm. f/4 objective with one thousandth of magnitude dispersion only.

I hope that these results, - on the other hand very useful to modern astrophysics -,  encourage  you to do similar things.

Best regards, J. Guarro.