spectro-aras.com

A spectrum taken last night of possible nova AT2108hld / TCP J00420310+4102331
https://wis-tns.weizmann.ac.il/object/2018hld
http://www.cbat.eps.harvard.edu/unconf/ ... 02331.html
At mag 16, this was difficult with the standard ALPY 600. The SNR is only ~10 so probably not good enough for a definitive identification but some Balmer emission lines at M31 velocity (z=-0.0017, NEDS) are clear and there is perhaps signs of a P Cygni profile at H alpha with a velocity of ~1700km/s

Robin

Note that the RV of M31 quoted (z= -0.0017) is the local RV of this region of M31, not the mean RV of the galaxy which is quite different (z=-0.001), because of the rotation of M31

Robin

Hello Robin !
Congratulation for the (first amateur ?) Nova spectrum extragalactic. It's very important results, very emotion for it and thinking when Hubble studies this galaxy and see Nova !!
For see a Nove at magnitude ~16 in M31, it's a big Nova, no ?
Regards.

Thanks Etienne,

mag 16 is an absolute magnitude of -8.5 at the distance of M31 (ignoring extinction) which is about right I think (perhaps a bit brighter than average)
It would have been much easier with the ALPY 200 but that does not have enough resolution for nova identification.

Cheers
Robin

Hi,

Very intersting. Is it visible through the imaging camera or the guide camera ? or do we have to find it using the coordinates and pointing at all the bright dots until we see a similar spectrum like you posted.

Starting November 1 I am retired and will permanently live at the Observatory and planned to get active in Spectroscopy again. Now I have time and I hope to have clear skies. Normally the area where I have the Observatory was very clear but this year it has not been good ... ¿ Global Warming ?

I am at North 22°36′12″ West 100°25′47″ and we call the area a semidessert area ...

I was very active in 2011 with my LISA on an AstroTech 8" RC f/5.6

Now that I got better mounts I hope my pointing also is better then before with my custom modified Losmandy G11. Look at the image of the new mounts. 2 pieces CEM 120EC2

regards Rainer

Hi Rainer,

What is the green fans used for that are fixed close to the CCD attached to Taka refractor on the first mount twoard us?
Do you use a weather station helping you to control the observatory?
Have you thonk about doing remote control with your observatory?

Cheers,

Benji

Hi Robin,

Impressive shot Robin!
Would it be usefull to remove M31 spectrum to get the pure nova spectrum?
This could make easier to identify nova type, isn't?

Benji

Benjamin Mauclaire wrote:Hi Rainer,

What is the green fans used for that are fixed close to the CCD attached to Taka refractor on the first mount twoard us?
Do you use a weather station helping you to control the observatory?
Have you thonk about doing remote control with your observatory?

Cheers,

Benji

Hi Benji,

Those fans are a part of my motor controllers for my motor controlled focusers and rotators.

Well I do not need to do any remote control anymore as in one and a half week I will live at the observatory.

Or do you mean to rent my Observatory ?

Theoretically my observatory can be controlled remotely but never did it, as I did not have anybody living near understanding the whole enchilada in case something failed. Now that I will live there perhaps I could rent it

Rainer

Hi Benji

Benjamin Mauclaire wrote:Hi Robin,
Impressive shot Robin!
Would it be usefull to remove M31 spectrum to get the pure nova spectrum?

M31 is so large that it completely filled the full length of the slit so the sky background subtraction would have already removed the galaxy spectrum. The problem is the low SNR. The blue continuum and the H alpha, beta emission lines are the only significant features. I looked for Fe II lines. They could be there but it could just be noise. I have decided to announce it as a nova on TNS though. Perhaps someone will take a better spectrum.

Cheers
Robin

Hi Rainer

Rainer Ehlert wrote: Is it visible through the imaging camera or the guide camera ? or do we have to find it using the coordinates and pointing at all the bright dots until we see a similar spectrum like you posted.

I use the goto controls (eqascom + Cartes de Ciel) to go to the coordinates published for the discovery. I check that I am in the right place by comparing the star field in the spectrograph guider image with DSS images and sometimes also by checking using astrometry.net
I then take a series of 10 second exposures from the guider image and add them to identify the "new star" target. (see attached image)
With a target this faint, I cannot see it in short exposures while guiding so I choose another star in the field bright enough to guide on and measure the offset of that guide star from the target.
I then calculate where I need to place the guide star so that the target will be on the slit and start guiding with the guide star at that position. (It is always a relief when the first spectrum appears 10 minutes later !)

Cheers
Robin