AAVSO Alert Notice 454: Monitoring of CH Cyg requested

[Robin Leadbeater]

50/100s cadence is probably not going to work for my setup. <=250s will catch a 500s period though (but with bad aliasing). Provided the read noise is not to large (my 314 is good for this) that should not damage SNR too much compared with 600s exposures. I will change my sub exposure times to 240s. I can still sum them for low SNR and reduce the individual exposures separately in the future.

Cheers
Robin

[Thierry Garrel]

Yes it's a good idea as readout noise is not strong for a 314L+
I will give a try, weather predictions has changed, at 180s. Thre is still a lot of signal in Ha (19000 ADU at 1200s) but readout noise of a ST10XME will become much more significant than the 314L.
Stephane who has a huge 30000 ADU/1200s in Ha with his 0.5m, will try one hundred second exposure.
What is interesting in this campaign is that spectroscopic survey goals has changed as Margarita discovered our capacity. Thanks to a joint effort and a fantastic feedback from a reactive PI.
Good luck
T

[Robin Leadbeater]

Here is the latest exact timing of Chandra observations and thanks from Margarita.

The weather is mixed here in the UK. We have warm spring weather and stable high pressure which is predicted to last for several days but there is alot of thin cloud around. Here is hoping for clear skies tomorrow.

Cheers
Robin




From: "Margarita Karovska"
Sent: Friday, March 23, 2012 6:01 PM
Subject: Chandra obs schedule


>
> Hi Robin,
> I don't know if the observers know that the remaining 600000 s of
> Chandra observations of CH Cyg are scheduled he Chandra observations of
> CH Cyg
> 21:31:23.489 GMT (Mar 24)
> to 13:04:43.489 GMT (Mar 25)
> I didn't notice this on the web...
> AAVSO has sent a special notice today.
>
> Thank you and please mention on the web site my deep gratitude for the
> beautiful and very helpful observations.
>
> Cheers,
> Margarita

[Christian Buil]

A sample of one hour observation of CH Cyg for the night March 24, 2012:



The spectra are taken with a Celestron 11 telescope (0.28 m diameter) and
a LHIRES III spectrograph equiped with a 600 grooves/mm grating and a 23 microns
slit (for a spectral resolution power of R = 3500).

The time resolution is of 180 seconds (a spectra obsrerved each 3 minutes). The
SNR is decent with these configuration.

We can observe signifcant profile evolution (to be confirmed )!

The important questions: more observation are requested ? Satellite observations are finished ?

Christian Buil

[Robin Leadbeater]

There are CHANDRA observations tonight! (See post my above)

> 21:31:23.489 GMT (Mar 24)
> to 13:04:43.489 GMT (Mar 25)


Observe if you can. Thin cloud/fog again here but I will do what I can.

Cheers
Robin

[Thierry Garrel]

Yesterday observations, 1 Go of data, 6H of time series of 180s and 300s individual exposures doesn't show obvious periodic variation of the H alpha line. Only during several hours a growing blue H alpha peak. I haven't finished to reduce all the spectra at different time resolution, 1h, 180s and 300s.
Christian, there is a lot of possibility of blending on this star and your variations seems to be blend. But perhaps with a slighty more resolving grate, 1200/1800, it could be more easy to probe the seeking 500s period. Well perhaps doesn't exist at all.
Stephane Charbonnel with its 500mm as done a wonderful observation of only 100s individual exposure (24.045, 24.096 March). It is under its range no variations seen in his spectra.
Some plots:

[Robin Leadbeater]

A sample of one hour observation of CH Cyg for the night March 24, 2012:

We can observe signifcant et true spectral profile evolution!

Hello Christian,

The large drift in wavelength of the H alpha peak is interesting (~1A) I have not seen shifts anywhere near as big as this. Is the calibration stability confirmed?

Cheers
Robin

[Christian Buil]

Hello Robin,

Relaod the page. The graph is updated with all my data available and better spectral calibration (time variation fllexure on Lhires is a permament problem).
eShel data seem not show Halpha peak intensity variations... more observations needed.

Christian

[Stephane Charbonnel]

Hello,

I send you two graphes.
Instrument : T500F6 Eshel#112 ST10XME
Site : Durtal(UAI949)
Last night : 24/03-> 25/03.

First is an extract of 30 min with a serie of spectra around Halpha (order 34). Exposures are 200 seconds (Star is very low at this time). I can notice no variation :



Second is an extract of 30 min with serie of spectra around Halpha but exposures are 150 seconds.



I can notice yet no real variation but it is not easy to see small variations in such graphes. Christian, I send you all fits file of ordre 34.

Stephane

[Olivier GARDE]

With some member of our club (CALA) we are at l'observatoire de haute provence for five days.
Last night, I take a CH Cyg spectra with a LISA and a C14.

Result on the following link :

http://photos.cala.asso.fr/displayimage ... play_media

and full size

http://photos.cala.asso.fr/displayimage ... fullsize=1

7 exposures of 120 secondes.