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Hi everyone, here are some velocity plots from my Alpy spectrum from 22nd March.
The wavelength calibration of my Alpy normally becomes more inaccurate at shorter wavelengths, this is something two other Alpy users have noticed. The error causes a 2 Angstrom blue shift at H gamma.

Best wishes, John

A spectrum for the 23-March-2021 taken by using a Star'Ex spectrograph (600 l/mm grating + 23 microns slit) on a 8-inch Newton telescope. The exposure is 12 x 300 seconds :



A more contrasted display:



The measured resolution is R=1700 and the SNR is 240 near 6400 A. Note the high efficiency of Star'Ex, here the result for a one-shot image of 300 exposure time only:



But note the major limitation of Star'Ex (a 3D-printing spectrograph) - the acceptable spectral range is between 5400 and 7400 A for the actual version. For IR or UV, and a nearly similar spectral résolution, the solution is Alpy600, LISA,... or the powerful and very recent UVEX by Shelyak.

Christian Buil

New processing of Star'Ex spectrum for the 23 March (the near-IR 7065A He is now visible):






Christian Buil

A near-IR spectrum (25-March-2021) - Pashen series is in emission:



Christian Buil

A comparison of the nova spectrum on Monday and yesterday evenings with my Alpy 600 spectroscope. If the visual magnitudes are assumed to be similar on the two evenings then an increase in the Balmer emission is visible with a small decrease in the HeI emission
Cheers
Hugh

Hi all,

I tried to observe the nova with a very strong atmospheric turbulence, especially for the second spectrum. Near-IR regions.





Clear sky!
Paolo

Hi all,

new spectra for March 26.





A couple of cloudy nights are expected here... Hope it's better for you!

Paolo

Hello all,

Very impressive spectra in the near infrared Paolo and Christian !!
Here is my update for the monitoring of the nova Cas 2021.
The following spectra were obtained with my Alpy 600, respectively, the 23th of March at 20 h 10 TU (resolution of 525, JJ = 2459297.3404) with an acquisition time of 36 min (12 x 180s) and the 24th of March at 19 h 55 TU (resolution of 529, JJ = 2459298.33) with an acquisition time of 18 min (6 x 180s) :
Clear skies,

Christophe BOUSSIN

At this time, I'm on the nova with an eShel spectrograph.

Evolution of the nova in 8 days taken with an eShel spectrograph (R=11000) and an RC400

H Alpha profil




H beta profil



Velocity of the Balmer's lines



and the full spectrum cut at 4000 Å because the blue part is very noisy (many obstacles like trees)