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Hello David,
May be I misunderstood the meaning of the word "flickering" . I spook of what we name in french "scintillation atmosphérique" .
My purpose was to point out that due to "scintillation atmosphérique" short exposure time (less than 60s) may lead to scattered measurement.
For example the same night on GK Per I did some V magnitude measurements (60s exposure time, S/N about 300), the magnitude variation was about 1/3 of those you observed. Unfortunately I did the magnitude measurement during only 20 minutes and not at the same time than yours so it is difficult to compare our results.

Hubert

Bonjour,

Trois spectres de GK Per du 18/01, 20/01 et 22/01.









Je constate que le continuum des spectres a évolué dans le temps, notamment celui du spectre du 18/01 est beaucoup plus chahuté que les suivants. Les traitements effectués sur spectres ont été identiques, j'ai refait plusieurs fois la réponse instrumentale mais on ne peut pas exclure une maladresse .

Je ne sais donc pas dire si cette différence est dû à l'évolution de GK Per ou bien à des conditions locales très différentes nuit calme le 18/01 et Mistral assez fort les 20/01 et 22/01 ou si le problème se situe entre l'écran et le clavier.

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 airmass and its effect is greatest at large values of airmass. The mean airmass during my observations of GK Per was 1.05 so the net effect of scintillation on my V magnitudes was just a few millimags, an order of magnitude less than the statistical uncertainty on the magnitude measurements.

David

Hi all,
The following spectrum of GK Per was obtained on 22 January at 20:57 UT.
Star'Ex LR (300l/mm, 80x80, 19microns slit) + Mak127

Hello all,

Hi Guillaume,
Happy to see a GK Per spectrum from a skilled Star'ex user !
Do you schedule to do frequent observations of GK Per and send your spectra for inclusion in the Aras database ?

Again, clear skies for a few hours on Monday evening, just enough time to take a second spectrum of GK Per...which was obtained on 23 January at 22:23 UT (resolution of 528, JJ = 2459968.4328) with my Alpy 600 and an acquisition time of 60 min (6 x 600s) :
Clear skies for all...as often as possible !!

Christophe BOUSSIN

Hi Christophe,
I don't have much time available and the weather is really bad right now
However, I will try to do some more GK Per spectra in February !
And yes, I sent my spectra to the aras database

Clear skies
G

Bonjour,

Spectre du 24/01




Hubert

Hello all,

Here, opportunities to observe GK Per are as rare as ever...
The following spectrum was obtained on 28 January at 23:39 UT (resolution of 527, JJ = 2459973.4857) with my Alpy 600 and an acquisition time of 50 min (5 x 600s) :
And now I'm waiting for the next clear night !!
Clear skies to all !!

Christophe BOUSSIN

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 all,

The following spectra were obtained with my Alpy 600 on 7 February at 18:41 UT (resolution of 521, JJ = 2459983.2785) with an acquisition time of 90 min (9 x 600s) and on 12 February at 20:56 UT (resolution of 531, JJ = 2459988.3722) with an acquisition time of 60 min (6 x 600s) :
Note : the 12 February spectrum has been modified with an updated instrumental response !

Clear skies to all !!

Christophe BOUSSIN