Forum der Vereinigung der Sternfreunde

Hi everybody,

Last night, I was able to do the spectrum of Nova Sct 2017 in high resolution R = 11000 with eshel spectrograph (11 exposures of 1200s each, magnitude about 10.9)

Here's the "full" spectrum, we see a whole series of emission lines with a P Cyg profil (probably type IV)


And the graphs of Balmer lines corrected from in heliocentrique velocity of 7.1 km/s)







From these graphs we can measure the expansion velocity of the Nova and we find the following values:
- H Alpha: -404.27 km/s (+/- 2.5 km/s)
- B Beta: -331.16 km/s (+/- 3.1 km/s)
- H Gamma: -325.31 km/s (+/- 3.5 km/s)

To see in the next days (if the magnitude of the nova not decrease too much) how will these velocity evolve ?

Great Oliver!

Berthold

Von meinem iPhone gesendet

Hallo,

These graphics are the complement of the excelent observation by Olivier.

Is NOVA Sct 2017, on the last night.

Regards, Joan.

Collapse of the H alpha line on my last spectrum last night in comparison to the 3 other spectra obtained with the same set up since the 14th July.

Bonjour Olivier,

This is the confirmation of yours observations.

Bien cordialement, Joan.

Hi Olivier and Joan!

Very nice work and highly interesting spectra. I am a bit surprised about the outcome because I would have expected a vice versa time order.

As far as I understand novae the outbreak first produces an optically thick wind which makes a classical PCygni profile. After some days the wind becomes optically thin and produces a strong emission line without PCygni absorption. However, in your case the strong emission comes first. Why?

Cheers, Thomas

Hi Thomas

I do not have enough knowledge to know what is happening. But it really is a very peculiar star.

Regards, Joan.

Hallo,

This is an actualizationn of NOVA Sct 2017 results.

The Halpha is again in outburs.

Joan.

Hi,

The NEW SCT 2017 is a real pit of surprises, the changes in its spectrum are constants.

Joan.

Aha, now my question above is answered. The optically thick pCygni profile ("fireball") now more or less disappears and changes to the optically thin (almost) pure emission line (expanding cloud). So, the above profiles from the end of July come from the fireball period. The central reversal right at about -300km/s is very interesting, though. It seems to be a kind of self-absorption due to additional material in the line-of-sight.
Cheers, Thomas

Hi,

The Hydrogen continues ascending.

Joan.

Hi,

NOVASCT2017 is keeping its emission in the Hydrogen bands.

Regards, Joan.

Here's my last spectrum taken last night.
Comparison with the last echelle spectrum of Joan (taken in the ARAS data base)


And Balmer lines (H Alpha and H Beta)

Hallo,

Complementing Olivier's information.
Variations of the NovaSct2017 on the last 24 hours.
The star continue having it's ascending tendence in the Hidrogen.

Joan.

Hi Joan

I am very impressed by your splendid spectra of such a week object like this nova. I use an eShel from shelyak with a telescope C14 , a little bit smaller than yours. I don't believe that I can create such spectra , such impressive spectra of such a week star. Have you any tricks, with guiding for instance? I use PHD FOR GUIDING but it is not so easy to hold the star in the center of the fiber.

Could you tell me some details how you get those spectra?

Berthold

Hallo Berthold,

I think that with C14 you can make good looks of the New Sct 2017.

REMOT telescope of Santa Maria de Montmagastrell. Via Internet.

I sent you two images where you can see my way of operating. I make some short comments.

1.- Visual control camera.

2.- Control software, open the sliding roof, start the telescope, open the CCDs, calibration lamp and tungsten.

3.- Cartes du Ciel, position the star to watch, works through ASCOM.

4.- Racquet and focusing through ASCOM.

5.- Control a plate of relays, on a Led that feedbacks the optical fiber. To view its position on the CCD guide.

6.- PHD2, a good tracking soft, through ASCOM. I use a glass slit and have double reflection, the position of the star does not match the fiber position. (ATIK314L +).

7.- MAXIM DL4, only for obtaining spectra. ATIK460EX.

Gladly, I can expand the information you need.

Friendly. Joan.

Thank you very, Joan, much for this Information .
Very interisting
But my fiberinjection from Shelyak has no slit !.

Friendly Berthold

Hallo Berthold,

I know that your fiber does not have a slit, I think, yours has a reflective glass, (to be able to do the guide), with a pinhole.

I and I have the same reflective glass, (also from the Shelyak house), but with a slit of 75 microns.

Some time ago I bought these slits at the Shelyak house and I took them for the echelle. The slit is not very annoying and I can orintate it very well, in the North-South direction. The optical fiber I use is like the one you have, 50 microns.

In the guide module I only use a single fiber (the one of, 50 microns), since the calibration and tungsten lamps are in the same guide module.

Regards, Joan.

Halo Berthold,

I have also an eshel spectrograph and I do auto guiding with Maxim DL 6.
I can auto guiding directly on the target into the fiber very well (3200mm local length) with less than 0,2 pixel peak error and RMS about 0,1 (guiding with an ATIK 314L+ in binning 2x2) and it works also with faint target like this nova (but with 3s exposure).

Before night, I just check the coordinate of the fiber X and Y and put this coordinate as a consign for auto guiding in Maxim DL.

I have an AP1600 mount and the polar align is less than 45'' off the pole.

Hallo,

The Hydrogen continue with it tendency to highing.

The last night, cloud in Piera and Sta. Maria.

Cheers, Joan.

Hallo,

The Hydrogen continue in ascending. Until when ?

No tinc por, Joan.

Great indeed!
Joan!

Friendly

Berthold

Hallo,

The NOVA SCT2017 continues to give surprises.

Regards, Joan.

Hallo,

Decrease the intensity of the Hydrogen.

Regards, Joan.

Hallo,
Although ns2107 brightness goes down. Over the last 24 hours it has increased its emission.
Joan.

An Atel on Nova Sct 2017 about some amateur spectra from ARAS database (amateur from Spain, France, USA, Australia, Italy)

http://www.astronomerstelegram.org/?read=10737

Hallo,

There are 2 graphs, where is shown, the evolution of Halpha of the Nova Sct 2017, in the last 5 days.

Regards, Joan.

Hi,

The Halpha emission of NOVA Sct 2017, has been the highest again.

Regards, Joan.

Hallo,

It is very possible that there is a reverse relationship, between, the increase in the brightness of the Nova and the decrease in the intensity of the Halpha.

This situation seems to have been the tone of the last months.

Regards, Joan.

Hallo,

One graphic is the Halpha evolution of Nova Sct 2017 on last days.

Another represent their maximums wiht a interval days from 2017 08 21.820 to 2017 11 07.733.

Friendly, Joan.