Spectra of The Summer Triangle

[Jack Martin]

Merlin 66 suggested I present colour spectra so here it is.

Jack

The Summer Triangle colour.pdf

[MjrTom]

Very interesting

[Jack Martin]

MjrTom,

Thanks for your comment I had hoped to post the image as a thumbnail not as an attachment can anyone help?

Thanks,

Jack

[Pavel]

Excellent work.

Now I haven`t got sufficient skills to attend spectroscopy on a level with professionals but I like it.

May You have to try an "Insert Image" or simply to add a link; no problem to convert PDF file?

[Jack Martin]

Pavel,

I am an amateur with modest equipment but years of experience in imaging stellar spectra thanks for your comments.

Jack

[Mark at Beaufort]

Jack this is interesting spectra of these 3 stars. I now appreciate and understand the information much more since your detailed talk.

regards

Mark

[jsandse]

Nice colour spectra of the summer triangle Jack.

I took a spectra of one of the stars of the summer triangle - Deneb two weeks ago around Halpha with resolution approx 6000. See picture below. Was hoping to see a p cygni profile on Halpha line at 6562 but didn't see much evidence for one. Going to try again in September with a higher resolution R approx 15000 to see what I can find....hopefully i'll be able to track changes and periodic behaviour in the stellar wind of the star at this resolution....

[Jack Martin]

Mark I can't see a way of replying to you I am really having difficulty navigating my way round oh well thanks for your comments I have laid out the spectra and identified the lines so its easy to understand just like my atlas. Thanks for your comments. How do I reply to jsandse?

Jack

[Jack Martin]

jsandse,

Thanks for your comments. This is a nice spectral profile. How can you tell there are changes in the stellar wind and which camera do you recommend for spectroscopy I see you have 3?

Jack

[jsandse]

Thanks Jack,

I use the skynyx for observing planets (not spectroscopy), the DMK21 for guiding and the Atik 314L+ for spectroscopy.

The camera to choose for spectroscopy firstly depends on the type of spectroscope you have which determines the size of chip you need.

eg in general echelle spectroscopes require larger chips to capture all the orders rather than classical and littrow spectroscopes.

Also with amateur specroscopes the width of the spectra that remains on focus is limited.

For a littrow spectroscope like mine 2/3 inch chip is large enough. You can of course use smaller chips which is often what people do as the cameras with smaller chips in them are normally cheaper!

So once you have worked out size of your chip you can look at cameras with relevant chip sizes and start comparing their:

- pixel size

- quantum efficiency

- read noise

- dark current

A lot of these cameras have these figures published - or some amateur has calculated them - if you look around the web you can find them.

You can use this data along with the specific details of your telescope and spectroscope in the simspec spreadsheet which can be found at:

http://f1.grp.yahoofs.com/v1/IIE9TpXNQ_-HeMNEIgcP7XhJp9ni4r60m7lo2iGhBujIY9OKzhvi4C7bY97F1AkDb6HrxYLE5J5-gz9InRadcg/simspecV3.3.zip

to determine how long it takes you to capture the spectra of a given star.

In terms of capturing spectra for littrows cooled CCD cameras using some of the sony chips are probably the best affordable ones on the market.

In terms of specific "affordable" cameras for the littrow:

A second hand Atik 16ic (or its successor the Titan) would be good to use.

But one of the best I think is the Atik 314L+ it appears from what I have read out there to outperform most of the others on faint objects due to its extremely low noise.

I hope this helps

cheers

John

[jsandse]

In answer to your question on measuring variability on deneb.

Spectroscopic variability in A type supergiant stars such as Deneb have been measured since at least the 1930s at the Lick observatory. You can read the paper by Paddock who observed Deneb over 6 years:

http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1935LicOB..17...99P&data_type=PDF_HIGH&whole_paper=YES&type=PRINTER&filetype=.pdf

The dispersion of the spectra I will be taking of Deneb is the same as Paddock took - approx 12 Angstoms per mm so I should be able to capture the variability he captured. Note that though he used a bigger telescope I have the advantage of using a far more sensitive camera especially at Halpha :0)

The Halpha line is optically very thick and hence any changes to it are a good indicator of what is happening to the solar wind at the surface of the star. A pro-am collaboration has recently (2010) taken place on this star to look at the variability of the Halpha line (amongst other things) to be used as input to the stellar model to estimate mass loss due to the stellar wind. The paper can be found here:

http://arxiv.org/PS_cache/arxiv/pdf/1007/1007.2095v1.pdf

cheers

John

[Jack Martin]

jsandse,

I have a Lhires III which camera do you recommend.

Jack

[jsandse]

Hi Jack,

Depends how much money you want to pay :0)

Personally I would recommend the Atik 314L+

I know Robin Leadbetter who has an LHIRES3 is planning to upgrade to upgrade his CCD to an Atik 314L+.

But you may want to also check with the designer of the spectroscope Christian Buil to see what his opinion is.

cheers

John

[Jack Martin]

jsandse,

I will check it out.

Jack