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Robin (or others) - I was wondering if you had agreed with Darryl yet on the details of the use of the Star Analyser in this study? Specifically have you agreed the "in field" references stars and the preferred position angle (PA) of the spectra with respect to the target stars? Is there a preferred exposure time to try to detect transients or just a required S/N ratio?

Also am I right in assuming the Target and reference star should be instrumentally corrected then both submitted and if not what is required.

I now have an SA set up and can reliably take spectra at between R= 70-90 depending on my local seeing which approximatly matches or just exceeds the spectral CA at ~13A/pixel.

Any update much appreciated.

Regards Andrew

Hello Darryl,

At date, we have only a few spectra (respectively 12, 12 and 6 for RY, DN and DR tau) from Christian Buil, Robin Leatbeather, Terry Bolhsen, Stéphane Charbonnel, Thierry Lemoults, Thierry Garrel, François Teyssier.

http://www.astrosurf.com/aras/Aras_TTau ... paign.html

I asked Darryl Sergisson for comments and recommandations

I have been looking at many of the spectra submitted (although i hadn't looked in the last couple of weeks). I have also aquired some myself using a 2m fibre fed instrument.

I am in the USA right now for another week or so, when I get back I plan to spend some time analysing all of the collected spectra and reviewing what has been achieved. At first look, all of the spectra collected look useful for one reason or another. I have even been working with Robin Leadbetter using star analyser spectra to monitor continuum accretion flux.

As for next Autumn's campaign, once I have had a good look at all of the data I will draw up a plan and send it to you for comments.

As soon as I have more comments from Darryl , I will contact you

We have a few weeks to get spectra. Send fit files to francois.teyssier (at) dbmail.com

Best regards

François Teyssier

Hi Andrew,

It is still a work on progress for me as far as the Star Analyser is concerned.

So far I believe I now have a robust measurement of DNTau based on the same reference star HD29646 that others here have been using so far for instrument response correction. (The ones listed by Darryl are not considered bright enough for amateur use)
http://www.threehillsobservatory.co.uk/ ... ra_42a.htm
I am also measuring a stable star nearby in the same field ( GSC 01829-00018) which can be used to correct more accurately for changes in atmospheric conditions if needed. So far I have not attempted to correct the spectrum using this star as the differences have been small. Darryl has all these data for my measurements to date and appears happy with what I am doing.
Although only my average spectra for DN Tau appear in the archive here, the individual spectra for all these three stars is being retained however as with this information Darryl can in the future reduce all the data to any common reference if necessary.

My observatory has been out of action since the start of the year after some storm damage but is up and running again so I hope to look at the other targets soon. My aim is to eliminate the need to rotate the field between targets by relaxing the choice of reference star in the same field to include any stable star as I have done for DN Tau rather than attempting to fit a main sequence A star in the same field as Darryl originally proposed. I still plan to use HD 29646 as the reference for instrument response so my results can be compared with others observers.

Cheers
Robin