I have been experimenting with different ways to do an accurate wavelength calibration. My problem is, while close, different methods give slightly different...
Hi Jeff, Using the Barycentre or alternatively a (Gaussian) curve fit to the line shape is much more accurate than using the peak value as you can use the...
... From: Jeff To: spectro-l@yahoogroups.com Sent: Tuesday, November 01, 2011 6:06 PM Subject: [spectro-l] Wavelength Calibration ... A proper Barycentre...
I agree with Robin, the max intensity is not an accurate way to identify line center. I have been told that barycenter is quite robust, whatever the continuum...
My, admittedly limited, experience is that the pros prefer using a Gaussian fit for wavelength determination, but even then we still have a big problem...
Hi Valerie, A question. When using the barycnter you set two vertical lines to determine the midway point. Is that correct? How do you determine where to set...
Yeah and I sent a status report for zeta Aurigae on 21 October and it came through today. Jeff Hopkins Phoenix Observatory (187283) Counting Photons Phoenix,...
Hi Robin, The AAVSO notice was published on the ARAS forum Nov. 21 http://www.spectro-aras.com/forum/viewforum.php?f=5 Unfortunatly, BW SCl is very very low...
You are perfectly right. But if the underlying continuum is quite flat and not noisy, then it will reduce the sensitivity. As for Gaussian, if the algo fits a...
Hi Valerie, if the spectrum has a slope in the continuum, as in your example, would it not be preferable to first divide the spectrum by the continuum to get a...
 1st I'v to tell you that after receiving many of good friends' help, and having been trying many many times, I can STILL never open our forum~~ but I went...
Which analysis software will run on Win 7? I have collected the images and I want to analyze them. Also how do I get Lodestar to autoguide? Marlin Costello...
Marlin, The main amateur spectra processing software, Vspec and IRIS, certainly run under Win7. Can’t help with Lodestar (never used it), but I would imagine...
Hi Martin, for Equivalent Width, yes I would pay great attention to the continuum. For line center, or barycenter, I do less. For barycenter/center line, Vspec...
Hi Valerie, What algorithm do you use to calculate line centre? How does differ from a barycentre calculation? Thanks Robin ... From: valerie.desnoux To:...
This is interesting and important. Precise wavelength measurement of a line profile that is repeatable is necessary for serious work. Most lines are not nice...
Marlin, to guide easily with a lodestar i suggest you to use phdguiding. Download driver from starlight xpress, install last version of phdguiding and select...
Hi, it is the same... only if you fit gaussian, the algo is different. V.- ... From: Robin Leadbeater To: spectro-l@yahoogroups.com Sent: Thursday, November...
Hi Valerie, If the calculations are the same then it is not a barycenter calculation. If you move the vertical measure lines on a flat continuum bracketing the...
Hi Jeff, A quick test confirms that Vspec uses the barycentre to calculate the line centre. The barycentre option in the calculations window gives the same...
Hi Jeff, ... From: Jeff To: spectro-l@yahoogroups.com ; RSpec_Real_Time_Spectroscopy@yahoogroups.com Sent: Thursday, November 03, 2011 4:06 PM Subject: Re:...
Hi Jeff, The attached pdf gives details of how this is handled by a professional astronomical spectrum analysis package (SPLAT -VO) Robin ... From: Jeff To:...
Hi Robin, I downloaded and installed SPLAT-VO. I calculated the EW of my kap Dra spectra and I got very similar results as per VSpec. Thanks to share this...
Hi Jeff and Robin, If I may jump in here, I find that the barycenter calculation is dependent upon where the 2 vertical lines are placed on either side of the...
Hi Marco, Interestingly SPLAT uses the median of the line as the line centre for its Quick calculation (equal area either side of the line centre) . This is...
