Forum der Vereinigung der Sternfreunde

Fascinating X-ray data from Michael but I would be interested to know, briefly, what this tells us about wind clumping. I'm also wondering how this new data differs from earlier(2000) HEG and MEG spectra for this star system (http://astro.swarthmore.edu/~emartel1/delori.htm).

Cheers, Bernard

_________________
Quicquid Nitet Notandum

Hi all,

The plots below shows Halpha + He profile for the date Dec. 23.958
and change in the yellow He line between 19H58M UT and 22H59M UT,
the Dec 23.

In only 2 hours the radial velocity change of the system
can be detected (here the He line the shift represent nearly 0.2 A, i.e. 10 km/s) !
Note that interstellar Na lines are not concerned.

Christian Buil

Due to Christmas Eve cloud I could only record a noisy single 300s spectra ...no sign of Ha emission

Cheers, Bernard

_________________
Quicquid Nitet Notandum

Hi Tony,

What puzzles me with Keith's Ha emission is the sudden increase in the depth of the Halpha blue-side absorption line when compared with other before and after spectra. Is this consistent with an emission burst?

Cheers, Bernard


[quote="Tony Moffat"]Yes, that makes everything look more convincing. While in Keith?s spectrum, the emission reversal in H-alpha is nearly central, in yours it is
on the red edge of the line. So it looks as if a relatively weak (and variable?) but significant emission component may be traversing the H-alpha line
with time (phase?).

But of course Robin is right: everyone needs to check for any extraneous features (e.g. a night-sky line) across the whole spectrum, that was not subtracted out. The best way to do this is by inspecting (and if not visible by eye, making line or column plots) in the 2D image before extraction to 1D.

Cheers, Tony

_________________
Quicquid Nitet Notandum

Keith kindly sent me copies of his raw 'H-alpha emission' data and I have to say that I now believe the emission line is the result of uncorrected individual x-axis shifts between exposures due to mechanical and temperature changes. I’ve looked at the raw spectra and only find a ‘step’ profile in all four exposures (see attached samples), which in itself could be interesting. I believe a slight overlap of the Ha line from separate shifted exposures has occurred, causing the apparent emission line. I will be interested to see if other recipients of the raw spectra will confirm this.

Cheers, Bernard

_________________
Quicquid Nitet Notandum

Hi Bernard:

Sorry, I don?t get it. All I see here in the two spectra you sent is a global x-axis (wavelength direction) shift of one spectrum wrt to the other. Assuming that the wavelength calibration for each spectrum will iron this out, I wouldn?t expect a problem.

Merry Christmas!

Tony

From: Bernard Heathcote (fg-spek-convento@vds-astro.de)
Sent: Monday, December 24, 2012 11:52 PM
To: fg-spek-convento@vds-astro.de (fg-spek-convento@vds-astro.de)
Subject: [fg-spek] Re: Request for observations of the 2mag star delta Orionis




Keith kindly sent me copies of his raw 'H-alpha emission' data and I have to say that I now believe the emission line is the result of uncorrected individual x-axis shifts between exposures due to mechanical and temperature changes. I’ve looked at the raw spectra and only find a ‘step’ profile in all four exposures (see attached samples), which in itself could be interesting. I believe a slight overlap of the Ha line from separate shifted exposures has occurred, causing the apparent emission line. I will be interested to see if other recipients of the raw spectra will confirm this.

Cheers, Bernard



Quicquid Nitet Notandum

_________________
Tony Moffat

The relative strengths of the Si XIII triplet will tell us something about the gas density (since each triplet component has a different sensitivity to density), and thus how far from the star the emission occurs in the wind (whose density drops off in a model-known way from the star). The new X-ray data will cover the complete orbit with better S/N than before, so we will be able to see where the X-rays are coming from due to the known eclipse parameters. Locating X-ray emission in hot stellar winds has been elusive in the past, so this will be the first time we get a real handle on this in any hot-star wind. It?s quite exciting and rather innovative yet simple in principal.

BTW, doing X-ray spectroscopy at very short wavelengths (1-10 A range) is kind of weird if you?re used to the optical (3500 ?10000 A). But it?s quite powerful as a technique to probe the very hot shock component of the wind.

Mike can probably give better answers here than I....

Best, Tony

From: Bernard Heathcote (fg-spek-convento@vds-astro.de)
Sent: Monday, December 24, 2012 7:33 PM
To: fg-spek-convento@vds-astro.de (fg-spek-convento@vds-astro.de)
Subject: [fg-spek] Re: Request for observations of the 2mag star delta Orionis




Fascinating X-ray data from Michael but I would be interested to know, briefly, what this tells us about wind clumping. I'm also wondering how this new data differs from earlier(2000) HEG and MEG spectra for this star system (http://astro.swarthmore.edu/~emartel1/delori.htm).

Cheers, Bernard



Quicquid Nitet Notandum

_________________
Tony Moffat

Hi Bernard:

I?m not sure i understand what you mean. Could you illustrate what you mean in the spectra? A quick answer to your question, though, would be that we shouldn?t be guided too much by preconceived notions of what we expect! The important thing here is to be 100% sure of the data extraction.

Best, Tony

From: Bernard Heathcote (fg-spek-convento@vds-astro.de)
Sent: Monday, December 24, 2012 9:19 PM
To: fg-spek-convento@vds-astro.de (fg-spek-convento@vds-astro.de)
Subject: [fg-spek] Re: Request for observations of the 2mag star delta Orionis




Hi Tony,

What puzzles me with Keith's Ha emission is the sudden increase in the depth of the Halpha blue-side absorption line when compared with other before and after spectra. Is this consistent with an emission burst?

Cheers, Bernard


[quote="Tony Moffat"]Yes, that makes everything look more convincing. While in Keith?s spectrum, the emission reversal in H-alpha is nearly central, in yours it is
on the red edge of the line. So it looks as if a relatively weak (and variable?) but significant emission component may be traversing the H-alpha line
with time (phase?).

But of course Robin is right: everyone needs to check for any extraneous features (e.g. a night-sky line) across the whole spectrum, that was not subtracted out. The best way to do this is by inspecting (and if not visible by eye, making line or column plots) in the 2D image before extraction to 1D.

Cheers, Tony



Quicquid Nitet Notandum

_________________
Tony Moffat

Hello Tony,

in the adnex I tried to calculate the RV using other lines and I found some differences I can not explain.....

frohe Weihnacht , Gruss auch an Ann

berthold

Hi Berthold:

Often this is due to the slightly erroneous zero wavelength one adopts. In any case, what really counts for binaries is the relative change in RV,
not the absolute values. I suspect it will likely turn out that different lines will give the same RV amplitude of variation. To check this quickly, you could calculate the CHANGE in RV from one line to another between two spectra where there is a big shift.

Frohe Weihnachten auch an Barbara,

Tony

From: Berthold Stober (fg-spek-convento@vds-astro.de)
Sent: Tuesday, December 25, 2012 10:31 AM
To: fg-spek-convento@vds-astro.de (fg-spek-convento@vds-astro.de)
Subject: [fg-spek] Re: Request for observations of the 2mag star delta Orionis




Hello Tony,

in the adnex I tried to calculate the RV using other lines and I found some differences I can not explain.....

frohe Weihnacht , Gruss auch an Ann

berthold

_________________
Tony Moffat

Hallo,

the three spectra are the only one. Always bad weather!

regards
Siegfried

Nice Siegfried,

Now what now strikes me, that your pink spectrum shows also a rather sharp
core (h-alpha) . The same I saw also respectivly Tony saw it. So it seems to me this couldt be perhaps a real changing of the h-Alpha profile...

Cheers
Berthold

Hi Tony,

I agree that if each spectra is individually wavelength aligned then the problem I raise won't occur. In the case of del Ori some/most of us are stacking 3x 10min spectra to achieve the required S/N performance and if we only use one neon calibration spectra at the start, or end, then mechanical shifts could result in one or more spectra being 'off'. There may be other processing related explanations for a false emission line.

When I reduce Keith's 22 Dec spectra I only see the H alpha 'step' (below), not an emission line.

Cheers, Bernard



[quote="Tony Moffat"]Hi Bernard:

Sorry, I don?t get it. All I see here in the two spectra you sent is a global x-axis (wavelength direction) shift of one spectrum wrt to the other. Assuming that the wavelength calibration for each spectrum will iron this out, I wouldn?t expect a problem.

_________________
Quicquid Nitet Notandum

Hi Tony,

Your brief explanation is exactly what I was seeking ... fascinating stuff ... thanks for that.

Cheers and Happy Christmas!
Bernard


[quote="Tony Moffat"]The relative strengths of the Si XIII triplet will tell us something about the gas density (since each triplet component has a different sensitivity to density), and thus how far from the star the emission occurs in the wind (whose density drops off in a model-known way from the star). The new X-ray data will cover the complete orbit with better S/N than before, so we will be able to see where the X-rays are coming from due to the known eclipse parameters. Locating X-ray emission in hot stellar winds has been elusive in the past, so this will be the first time we get a real handle on this in any hot-star wind. It?s quite exciting and rather innovative yet simple in principal.

BTW, doing X-ray spectroscopy at very short wavelengths (1-10 A range) is kind of weird if you?re used to the optical (3500 ?10000 A). But it?s quite powerful as a technique to probe the very hot shock component of the wind.

Mike can probably give better answers here than I....

_________________
Quicquid Nitet Notandum

Hi Berthold,

I'm confident that Ha core sharpness is cause by the 6564A telluric line.

Cheers, Bernard


[quote="Berthold Stober"]Nice Siegfried,

Now what now strikes me, that your pink spectrum shows also a rather sharp
core (h-alpha) . The same I saw also respectivly Tony saw it. So it seems to me this couldt be perhaps a real changing of the h-Alpha profile...

_________________
Quicquid Nitet Notandum

Here is my three hour coverage from last night.

Cheers, Bernard

_________________
Quicquid Nitet Notandum

Hi Bernhard,

i think the H20 line makes the Ha core intensive. This should be viewed critically, however is already a change observed on the red side.
What resolution do your spectra?


Cheers
Siegfried

Concerning the Keith observation, a spectral shift during the observation
seems to be actually the possible cause of problems. The strange profile shape
does not seem caused by telluric lines because they are too weak. The spectral
shift is probably still relevant. But I have not received Keith data, and therefore
it is difficult to make advanced analysis for me ...

Below, I put on the same graph data available from C. Buil and T. Garrel. It is very
instructive because we can better track the live evolution and this is also
(note periodic radial effect). It is also possible to better detect
potential problems and increase reactivity...

This analysis is possible because Thierry Garrel data are public on his blog:

http://gabalou.canalblog.com/archives/2 ... 54217.html

I also have also a public page with the journal of observations:

http://www.astrosurf.com/buil/campaign/deltaori/obs.htm

This is a good and important thing and effort, but the ideal solution is to collect all the observations
in the same database. See for example the actual ARAS AZ Cas campaign:

http://www.astrosurf.com/aras/surveys/a ... as_tab.htm

This is fundamental for collaborative work between amateurs (amateurs are not competitors!), for common motivation, for implicate
more observers, for a direct and fast check of observations with similar protocol...
(remember that the spectrography is a young discipline for many observers).
The example of the AAVSO in the variable stars domain is excellent. It is a key for
the development of amateur spectroscopy and an effective proam collaboration.

Without a doubt, the scientific analysis is a matter for professionals.
But amateurs are not more than observers - they can make themselves
preliminary analyzes, for example by a simple data comparison (for the present
and also for the future, by adding more observations - that is one of the interest
of a common database or common and public campaign page).
These first analyzes can also help professionals.

I propose to consider this for future campaigns.

Christian Buil

I am so new in the spectral world that maybe my data look so bad.

I am happy to get your comments.

Sincerely,

Dong .Li

Hi Keith,

My impression after an analysis of your raw data: the origin of distorsion shape on your Halpha line is probably a focus problem of your spectra on the CCD surface.

Use Lhires III with a KAF-1600 is not a simple task, and particulary
in the very near IR region. Remember, I have optimized the Lhires III spectrograph optical configuration for KAF-0400
CCD familly, not KAF-1600.

In some circonstances observers can use the KAF-1600, ... but it takes a lot of care in settings. Not easy. Configuration with a 1200 t / mm grating and more moderate spectral resolution are prefered.

I note a double lined aspect in your neon line (see attached images).
A typical aspect indicating poor focus. This may explain the Halpha shape distorsion. So for me, the observed profile is not real.

Other point, it seems that you do not use reference star for compute
the instrumental response. You confirm? The shape of your continuum is can be improved by using a strict protocol.

Finally, I found an integrated signal per sample of nearly 20500 ADU at Halpha region. That seems low for a star as bright and a 12-inch telescope. You use what slit width?

Christian

Hi,

For info, attached, the raw spectral profile (simple add along colum) of the the first 600 sec. acquisition. The spectral resolution is not so bad
in the raw data after a
better analysis, because your spectrum trace is in the upper part of
the image, less affected by defocus double lined effect. Finally, telluric
lines can also explain part of the apparent distorsion.

Also during your 4 x 600 sec. the spectrum is very stable along
the spectral axis. A good point. I can not observe large mechanical flexure.

The apparent emission in the core of of He line is the consequence of
of lag effect (ghost image of neon latest calibration image) - see attached
2D image.

Your spectral calibration is perfectible because the exposure time
for neon lamp is very short (1 sec). Adopt 10 seconds exposure
for a better SNR.

Christian

Hi Christian, Keith,

I agree that focusing appears to be the reason for the distorted Ha line. As the image below shows, the poorly focused neon line is showing the 'step' discussed earlier. Assuming Keith is using a 35um slit the FWHM should be <4 pix, not the 6 pixel he is getting ... with a 30-35% loss of resolution.

Cheers, Bernard

_________________
Quicquid Nitet Notandum

I have fully processed data given by Keith with ISIS software.

See plot below (I have rectified manually the continuum and
erased H2O lines by using a numerical model of atmosphere).

The red feature is stable during the 2400 sec. observation
(I have also processed individually each of 4 availables file).
The form seem now probable (very different from your first version).

In the plots below also a comparison with my 22.9 dec. spectrum of delta Ori.

The situation is very strange because the very different aspect of Halpha
line. Remenber also, during the 0.027 day obsservation the feature is stable (it is not a very fast event if true).

Keith, a simple curiosity, can you check the intensity coherence of the incrimined spectrum with the spectrum taken at different date for absolutly confirm the
identification of the object (a 6.7 star is present north of delta Ori for example ?).

Christian

Bernard, I agree. I found the neon lines more sharp left of Halpha, which is consistent with the shape of the neon lines. Keith, ISIS measure a mean spectral resolution of about R = 7500,
The lost in resolution is the consequence of defocus (you can expect
R = 12 000 or more if you use the 2400 l/mm grating).

For the present, the question is the relatively low intensity of your spectra traces, Keith, for a star of magnitude 2 and if you use a large slit
(35 microns). It is standard for you ?

Christian

Hi Bernard and Christian,

Thanks so much for your efforts in resolving this issue. I started writing a reply and then discovered Christian posted 2 more messages. Please allow me some time to go over all of the comments and I will get make a reply tomorrow. This is a real positive learning experience for me. More importantly, you have saved Tony and Noel from chasing inaccurate data.


Cheers,

Keith Graham

Christian,

I fully agree that we should attempt to add all campaign spectra to a common database but are you suggesting to use your one for delta Ori or it that a suggestion only for future campaigns? If you want to add our del Ori spectra to your database (http://www.astrosurf.com/buil/campaign/deltaori/obs.htm) do you want the continuum rectified or will you do that?

Bernard

[quote="Christian Buil"]

........This is a good and important thing and effort, but the ideal solution is to collect all the observations in the same database. See for example the actual ARAS AZ Cas campaign:
http://www.astrosurf.com/aras/surveys/a ... as_tab.htm
This is fundamental for collaborative work between amateurs (amateurs are not competitors!), for common motivation, for implicate
more observers, for a direct and fast check of observations with similar protocol...
(remember that the spectrography is a young discipline for many observers).
The example of the AAVSO in the variable stars domain is excellent. It is a key for the development of amateur spectroscopy and an effective proam collaboration.

Without a doubt, the scientific analysis is a matter for professionals.
But amateurs are not more than observers - they can make themselves
preliminary analyzes, for example by a simple data comparison (for the present and also for the future, by adding more observations - that is one of the interest of a common database or common and public campaign page).
These first analyzes can also help professionals.

I propose to consider this for future campaigns.

_________________
Quicquid Nitet Notandum

I'm finally getting all of the processing cobwebs out - here's a spectrum of delta Ori from earlier this month. I know - before the campaign, but the weather here has been pretty cloudy. Tomorrow night is supposed to be clear but windy.



Ha! I just noticed the axis labels are swapped!

About your spectrum Keith, one can note the great similarity of processing result between Bernard and me, which is encouraging.

Bernard, the question about the level of processing for an archive is very important.
My opinion is that we must follow the BeSS standard (Meudon Be Stars data base).
That is to say that we must archive the less processed spectra that professionals can apply their own methods above. This is very important.

We propose to have a version in which the continuum spectra are not corrected and in which the telluric lines are present. However it is your responsibility to make a good spectral calibration and a instrumental response removal (a standard job in a normal processing pipeline)!

See BeSS infos here (Help section and FITS format for archive):

http://basebe.obspm.fr/basebe/Accueil.php?flag_lang=en

Of course, it is not forbidden to archive also processed and analysed spectra. In the case of delta Ori is useful for a quick look to have also rectified continuum spectra and "dry" atmosphere spectra.

For the file name I highly recommend this convention:

_yyyymmdd_fff_objectname_yourname.fit

I think we are going to propose with Thierry Garrel an ARAS archive for delta Ori spectra in the very near future. But here, the opinion of professional is also important.

Christian

Hi all,

The spectra all look wonderful. I received Keith's spectrum, but with a houseful of company, I haven't had much time to look at them. It may be instrumental, but if the emission was real, we need to keep monitoring it to see if there is any real emission... especially if we look closely 5.7 d after his observation.

Thank you all for the wonderful work over the holiday. Thanks for the X-ray spectra Mike.

Clear skies, and happy holidays to everyone!

Noel

Hi Christian and Bernard,

Your time and efforts at working on my spectrum is deeply appreciated, and your comments are extremely helpful.

I became aware of that double middle neon line when I was processing these spectra. I had always used the first line as the primary indicator of focus. I adjust my collimator lens to sharpen that first line. Unfortunately on Dec 22, that first line looked good to me, so I went ahead and started imaging. Lesson learned. I need to check ALL lines when I adjust the collimation lens.

Your comments have raised some questions, so would you please offer some clarification?:

1) According to my ISIS data log for this spectrum, the resolution was around 12,500. I knew that was low for my equipment (I am using the 23u slit, 2400 l grating, ST8 camera, 12”SCT@f10). I generally get a resolution of between 14,500 and 16500 depending on conditions (I have submitted 3 other Del Ori spectra with resolutions at 14247, 14733, and 16 952). Since the requirements of this campaign are >10,000, I figured the 12,500 was OK but certainly not desirable. But Christian, you said you were getting an ISIS resolution of only 7500. I have run these images through ISIS multiple times and each time I come up with around 12,500. So now I am disturbed as to how our resolution numbers could be so different. Would you please comment on this?

2) You referred to focus as being a probable cause for the false emission line. Are you referring to the focus of the Ne lines or to the focus of the 2D image? I see now from the double Ne line that the collimator lens required adjustment. But the 2D images looked sharp to me. Are you saying the focus on the 2D images also needs to be improved?

3) Christian, do you think the low ADU count to which you refer might be due the low resolution? I am using a 23u slit. Are you suggesting I use the 35u slit instead of the 23u slit? I would think 23u would be plenty wide for a mag 2 star. Is this not true?


4) Christian, you asked if I would do an intensity review of my other Del Ori spectra to be certain I was on the correct star. I am aware of the 6.7 star to the north of Mintaka. I checked the resolution on the ISIS logs for each of 3 dates along with the Ha median ADU for those dates. The results are:
Date Resolution Ha Adu
12/13 16552 10719
12/22 12563 7049
12/23 14248 10139

As you can see, the ADU count appears to be related to the resolution. It may also be due to some differences in image focus. But I am confident that I am on Mintaka for all images. That said I will certainly make myself more aware of this the next time out (cloudy since Dec.23 and not looking good over the next few days).

5) I was not aware that the KAF-1600 chip was so much more difficult to work with. I do have an ST7 camera with the KAF- 400 chip, but since I can get only 2 neon lines for calibration, I have been using the ST8 in order to get 3 lines. You mention that the ST8 takes a lot more care in the settings. Could you please be a little more specific as to what those settings are?

6) I had not noticed the emission line in the core of the He line. Did you see this in the last 2 images as well? I would think that ghost would have disappeared after the 1st image. The lag effect to which you refer was a question I posed a number of months ago. I was concerned as to whether or not those lines in the first image would be eliminated in the ISIS processing. I was told that ISIS removes them, so I do not understand why they are still showing up in the HeI line of the profile (I actually did not see them in the images I processed).

You are correct, Christian, in that I have not corrected for instrument response. This is something that I have ignored until now because I was under the impression that this was not so critical for high-resolution spectroscopy. Bernard has convinced to learn to apply IR to my profiles. I am now practicing the derivation of a good IR profile. Once accomplished, I will begin applying that in ISIS. Another lesson learned.


I want to thank you both for your patience, effort, and perseverance in resolving this issue. As I said earlier, the most important thing is to find the cause for that emission line. It is hoped that by determining the cause to be my spectroscopy will keep Tony and Noel from pursuing a wild goose chase .

Cheers,

Keith

I've given my private responses to Keith's questions, with copy to Christian, as they are not directly relevant, except to Keith, to this campaign.

Cheers, Bernard

_________________
Quicquid Nitet Notandum

Hi Christian,

I think the minimalist reduction standards for BeSS data are excellent and, unless the pros have different needs for delta Ori, should be followed for this campaign. The only reason I asked about continuum rectification is that the spectra displayed on your database appear to be rectified and 'dried'.

Cheers, Bernard

_________________
Quicquid Nitet Notandum

Bernard,

I put on my delta Ori page rectified spectra to allow a quick overview of the appearance of the spectrum for a given date. This is a first visual analysis. In addition, as you know, the telluric lines removal procedure is a great way to check if the spectral calibration is performed correctly.

On my page I put the possibility to download the unrectified spectrum (most important) and a spectrum with a more advanced processing (telluric lines removed, rectification of the continuum to unity intensity by a carefull fitting, and correction of heliocentric velocity of the star) - It is an example of presentation.

A small correction for the naming of spectral files:

_objectname_yyyymmdd_fff_yourname.fit(s)

The "_" before the object name is added for clearly identify processed spectra.

Christian

Hi everyone observing del Ori:



Attached is a preliminary light curve (upside down!)
and discrete Fourier transform of the first 9 days of MOST
photometry of delta Ori. Looking very nice so far: nice smooth light curve but with some interesting changes in the secondary minimum.

Best, Tony

_________________
Tony Moffat

Hi Tony,

Impressive, for an amateur photometrist, millimag resolution!
I was initially a bit puzzled by the Fourier transform result until I released that the reciprocal of the prime period (around 0.3 c/d) agreed with the obvious magnitude period of about 3.3 d/c.

Cheers, Bernard

_________________
Quicquid Nitet Notandum

Hi Bernard and all!

I follow this campaign from the background, of course, an let me first say that this run is quite spectacular from my point of view. I expected good results but not as presented here. Congratulations for this great work! Yes, it's a space telescope. I want to encourage everybody to get in touch with amateur photometrists. I tried it many times for Germany but haven't been too successfull, yet. They could make great contributions for future campaigns. Binding the domains spectroscopy and photmetry together is perhaps one of the next major steps for stellar ProAm research.

Cheers and congrats again, Thomas

Hi Thomas,

While I can only speak for myself with any authority I do believe I can say that amateurs greatly appreciate acknowledgement and feedback (even negative if constructive) from the professionals .. it goes a long way to making the effort interesting and worthwhile ... many thanks for your kind words.

I think the best way to get (some of) the small army of amateur photometrists involved in a campaign is via the AAVSO ... once Arne Henden is aware of a pro's needs he is very helpful.

Cheers, Bernard

_________________
Quicquid Nitet Notandum

Hi all,

Attached, aspect of Halpha region for the date Dec. 26.82 + cumulative plot.

Christian

Hi Tony and all,

Attached a tentative of comparison between photometry and available
spectrograpy material.

The spectroscopic data used are for the date:

Dec. 17.936 (C. Buil)
Dec. 18.820 (T. Garrel)
Dec. 19.907 (T. Garrel)
Dec. 20.803 (T. Garrel)
Dec. 22.838 (C. Buil)
Dec. 23.958 (C. Buil)
Dec. 26.821 (C. Buil)

The radial velocies are corrected from a mean radial shift of 16.0 km/s (source SIMBAD)
and from computed heliocentric RV for the date.

The zero velocity correspond to wavelength 6562.80 A.

More data are needed for densifier the plot !!!

If you want, you can send me your spectra (before rectification of the continuum and telluric lines removal) to try to complete the graph. If possible FITS format clearly specifying UT date and instrument description.

My email: christian.buil_at_wanadoo.fr

Indicate is you are OK for an archive on a future ARAS page about
delta Ori (It is possible to extend the observation beyond the current campaign of course!).

Tony, what about the color used for photometry?
Do not hesitate to provide the light curve, it is very exiting to follow system activity in direct !

Christian B

Dear Christian:

Thanks for this comparison between MOST photometry and the spectra. Are the RVs more or less reliable? They imply that the star whose spectral lines dominate (i.e. the O9.5II primary) is behind (inferior conjunction)at primary (deeper) minimum. While the secondary minimum is highly variable, it will be interesting to see how the primary minimum varies, if at all.

This is the only format we?ll get the MOST photometry in for now until all is done and the final extraction is completed later in January. It?s rather exceptional to get even this much, given the modest nature of the mission. MOST observes in only one filter, a ?super? V, i.e. centred around 5500A and c. 2000A wide. It would be very useful to have supplementary (precise!) colour information, e.g. from ground-based amateurs! Any of simultaneous UBVRI and NIR would be useful.

Best, Tony

From: Christian Buil (fg-spek-convento@vds-astro.de)
Sent: Friday, December 28, 2012 9:00 AM
To: fg-spek-convento@vds-astro.de (fg-spek-convento@vds-astro.de)
Subject: [fg-spek] Re: Request for observations of the 2mag star delta Orionis




Hi Tony and all,

Attached a tentative of comparison between photometry and available
spectrograpy material.

The spectroscopic data used are for the date:

Dec. 17.936 (C. Buil)
Dec. 18.820 (T. Garrel)
Dec. 19.907 (T. Garrel)
Dec. 20.803 (T. Garrel)
Dec. 22.838 (C. Buil)
Dec. 23.958 (C. Buil)
Dec. 26.821 (C. Buil)

The radial velocies are corrected from a mean radial shift of 16.0 km/s (source SIMBAD)
and from computed heliocentric RV for the date.

The zero velocity correspond to wavelength 6562.80 A.

More data are needed for densifier the plot !!!

If you want, you can send me your spectra (before rectification of the continuum and telluric lines removal) to try to complete the graph. If possible FITS format clearly specifying UT date and instrument description.

My email: christian.buil_at_wanadoo.fr

Indicate is you are OK for an archive on a future ARAS page about
delta Ori (It is possible to extend the observation beyond the current campaign of course!).

Tony, what about the color used for photometry?
Do not hesitate to provide the light curve, it is very exiting to follow system activity in direct !

Christian B

_________________
Tony Moffat

Hi Thomas:

I suspect that the reason for the apparent lack of enthusiasm for photometry among amateurs in Germany is simply the lousy climate. Better and in many ways easier, is to do slit spectroscopy, where the calibration is built in, i.e. the spectrum itself (all wavelengths obtained at the same time!) acts as its own calibrator, if you are only interested in continuum-rectified spectra (the most common case anyway). In photometry, you have to calibrate the brightness levels. This is done for bright stars by observing other reference or standard stars in different parts of the sky during the same night; this normally requires photometric conditions, which are rare in central Europe. For fainter stars (V > ~8 mag) you can often find one or more other star in the same (normally narrow) CCD field, which makes differential photometry (clusters, variable stars) more doable in poor climates, although never as good as in good climates.

So, in bad climates you could simply say it?s too difficult; leave it up to those in good climates. That?s more or less what the profis do, except that they share, i.e. people from all climates can go to Chile, Hawaii, etc, to use common instruments, available by peer evaluation for the best science in all disciplines. The down side of that is that there is rarely enough time available to carry out monitoring projects. That?s where amateurs can make the biggest contribution, with their large numbers and readily available backyard instruments. But Germany is a high-tech country, so it is understandable that amateurs there want to try out their personal instruments on various projects, especially in spectroscopy.

That?s my take in this....

Best, Tony

From: Thomas Eversberg (fg-spek-convento@vds-astro.de)
Sent: Friday, December 28, 2012 3:54 AM
To: fg-spek-convento@vds-astro.de (fg-spek-convento@vds-astro.de)
Subject: [fg-spek] Re: Request for observations of the 2mag star delta Orionis




Hi Bernard and all!

I follow this campaign from the background, of course, an let me first say that this run is quite spectacular from my point of view. I expected good results but not as presented here. Congratulations for this great work!
Zitat: Impressive, for an amateur photometrist, millimag resolution!
Yes, it's a space telescope. I want to encourage everybody to get in touch with amateur photometrists. I tried it many times for Germany but haven't been too successfull, yet. They could make great contributions for future campaigns. Binding the domains spectroscopy and photmetry together is perhaps one of the next major steps for stellar ProAm research.

Cheers and congrats again, Thomas

_________________
Tony Moffat

That might well be, Tony. I agree, of course, that spectroscopy can be better performed than photometry, at least in Europe. However, this is (as always) a matter of the target necessities. Luckily you once sent me to Mexico to do photometry and I learned how to do that, you remember? I used a classical photometer (CO2-cooled) and much later I learned that CCDs do a very fine job. I am not familiar with the necessary accuracy for certain objects but found results for a 12mag delta Scuti star in the German photometry group. They achieve accuracies better than 50 mmag. I do not know if a comparison star was in the FOV but they did it anyway.

I informed the German fellows (see http://www.bav-astro.de/index.php?sprache=en) but they do not jump on. I presume this is a matter of information rather than interest. Since my first unsuccessfull try for WR 140 some years ago I ask myself how to bring the two complementary fields together in the amateur community.

With my remarks I only want to remind everybody that we should repeatedly keep the photometrist in mind.

Just my to pence. Thanks again for your spectecular delta Ori achievements. Go ahead!

Thomas

Tony,

By using telluric lines as reference I estimate the calibration error equal to +/-0.8 km/s around Halpha on eShel data (for an SNR of nearly 200).

Christian

Tony,

By using telluric lines as reference I estimate the calibration error equal to +/-0.8 km/s around Halpha on eShel data (for an SNR of nearly 200).

Christian

Hello,

3 more profiles of the last (-5deg-cold) night.
Interesting are the widths wings on the red side!

Siegfried

Hello,more south in Europe and 20 deg more than Siegfried, new observations availables from Montpellier.
http://gabalou.canalblog.com/archives/2 ... 54217.html
A compilation of all the observations from diferrent amateurs would be very interesting not only for professionnals but for amateur too. Checking the reliability of our data is very important in this kind of campaign. A webpage with raw spectra, without heliocentric or telluric correction would be welcome.
Cheers
Thierry 

2012/12/29 Hold Siegfried <fg-spek-convento@vds-astro.de (fg-spek-convento@vds-astro.de)>

_________________
Thierry Garrel
Observatoire de Fontcaude, Montpellier, France
SpectroBlog http://gabalou.canalblog.com/

Hi Siegfried:

Great spectra ? thanks! The red wind depressions could be the broader-line companion near max RV, while the narrower-line bright-giant primary?s RV is shifted to the blue. We?ll of course evaluate this once we have all the spectra in hand.

Best, Tony

From: Hold Siegfried (fg-spek-convento@vds-astro.de)
Sent: Saturday, December 29, 2012 7:28 AM
To: fg-spek-convento@vds-astro.de (fg-spek-convento@vds-astro.de)
Subject: [fg-spek] Re: Request for observations of the 2mag star delta Orionis




Hello,

3 more profiles of the last (-5deg-cold) night.
Interesting are the widths wings on the red side!

Siegfried

_________________
Tony Moffat

Sigfried,i checked your DeltO3 spectra and i had several questions:
- The observationnal date in the fit header is dec 29 while the mjd obs date is 56290. It should be Dec 28 ?
- I cannot check the calibration on the tellurics you don't have any in your spectra. Did you remove it or it was so dry ?
- There is a big shift of calibration between your spectra and mine taken nearly at the same date if Dec 28. My residual error of calibration check on the tellurics is less than 0.01A. Do you have check your calibration law or the spectra is not from Dec 28 ?
Cheers
Thierry
   

2012/12/29 Tony Moffat <fg-spek-convento@vds-astro.de (fg-spek-convento@vds-astro.de)>

_________________
Thierry Garrel
Observatoire de Fontcaude, Montpellier, France
SpectroBlog http://gabalou.canalblog.com/

Hi all:

On 18 and 23 Dec., I took some spectra of Mintaka, now I put the processed result here.

I find that Ha goes to the blue wing. Hope to get your comments.

Thanks.

Dong

Hi Tony,
I would love to make more spectrum but the fog is in this season at 800 meters . My observatory is located at 450 meters, clear nights there are very rare!

Thierry, I have the spectra of midnight, 28 to 29.12 made.
delta01-28.12.2012 beginning of the exposure 23:08
delta02-28.122012 beginning of the exposure 23:39
delta03-29.12.2012 beginning of the exposure 00:10
The spectra are not corrected H2O, the air was very dry.
I will check the calibration, with strong H2O lines, it is much easier.

Cheers Siegfried