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Spectra of Nova Ser 2025 were recorded with a LISA on a C11 on 25th July and 2nd August, 8 days apart. When these spectra are compared in relative flux, it appears that the H-alpha emission line is increasing in strength.

novaser2025_20250725_917_D_Boyd.png

However, when these spectra are ...

Spectral image and resulting spectrum of C/2023 A3 recorded on 17th October with a LISA spectroscope on a C11 scope. During 40 mins of integration the comet dropped in altitude from ~24 deg to ~16 deg. The spectrum was response corrected with a spectrum of the B9.5III star HD149121 recorded at an ...

Hello,
Recent evolution of Nova Vul 2024 at low resolution. C-11 + LISA, R~1100, flux-calibrated with concurrent V-band photometry.
David

Hi Francois,

Yes, good to be back. :-)

I use a LISA on a C11. I now use the following 22 lines from the LISA Ar/Ne lamp in a .lst file with a 4th order polynomial. This typically gives an rms in ISIS of around 0.08 and a resolving power of about 1100.

4
1.8
7383.980
7272.936
7147.042
7067.218 ...

A spectrum of C/2022 E3 ZTF taken on 6th February with a LISA spectrograph on C11 scope. Emission features tentatively identified.
David

Another spectrum of GK Per as it slowly fades. This was calibrated in absolute flux with a concurrently measured mean V magnitude of 10.95.
David

Hello Hubert,

Yes, these are different processes. Flickering is intrinsic in the accretion process in a CV while scintillation is an atmospheric phenomenon. There is a useful source of data on scintillation at http://astro.corlan.net/gcx/scint.txt. This shows that scintillation varies strongly with ...

Hello Hubert,

According to Bruch, A&A, 266, 237 (1992) the mean B-V colour index of the flickering light source in GK Per is close to 0 so the B and V magnitudes should change together, subject to the stochastic variation inherent in the flickering process.

The exposures were alternately 10 sec in ...

Here is another spectrum of GK Per taken on 20th January and calibrated in absolute flux using concurrently measured V magnitudes with a mean of V = 10.96.

gkper_20230120_842_D_Boyd.png

I continued to record B and V magnitudes for 1.4 hrs while recording the spectra and the resulting light ...

Another spectrum of GK Per taken with a LISA (R~1000) and flux calibrated using a V magnitude concurrently recorded by Franky Dubois (AAVSO AID).

David