How narrow is the aperture?

[Kano Ryouhei <ryouhei.kano@nao.ac.jp>]

Dear Golub san, or others,

Thank you for your suggestion about the diffraction. But, I have no
information on the width. 

Could you give me the following numbers for the aperture?
	- The width of the X-ray aperture.
	- How much of the annular is masked by the entrance aperture
          plate.
(I found the diameter of the X-ray aperture in the instrument paper.)

If you give them, I can calculate the diffraction pattern.

Regards,
R.Kano


From: Leon Golub <golub@head.cfa.harvard.edu>
Subject: Re: active region birth/death?
Date: Mon, 21 May 2007 12:34:26 -0400
Message-ID: <4651CA12.4050005@head.cfa.harvard.edu>

> Dear Kano-san,
> 
> The PSF of the XRT at wavelengths longer than 60A is given by the
> standard diffraction formula, using the width of the entrance annulus
> as the aperture size.
> 
> For your temperature plot, please be aware that a filter ratio does not
> give a meaningful temperature. I strongly suggest that you give it a
> different name, such as "hardness". There is no quesiton that spurious
> effects will appear if you take ratios using the Al/mesh combined with
> any other filter.
> 
> Leon
> 
> 
> Kano Ryouhei wrote:
> > Dear Mark san,
> > 
> > Do you have any quantitative information about the diameter of the
> > gaussian core of PSF for the Al/Mesh filter and the other filters?
> > I'm analyzing the temperature above the south pole limb taken during
> > the eclipse on February 17, 2007. We used Al/Mesh and Ti/poly for the
> > eclipse observation.
> > 
> > Just on the limb, the temperature is high, but emission measure is low
> > (See the attached PNG file). This may be a spurious structure caused
> > by the diffuser image of Al/Mesh than the Ti/Poly image.
> > 
> > The attached plots shows the several profiles in the south pole as the 
> > function of the distance from the sun center (limb=1).
> >   - The upper pannel shows the intensities: Al/Mesh(red) and
> >     Ti/Poly(black).
> >   - The center pannel shows the temperature.
> >   - The lower pannel shows the emission measure.
> > 
> > Regards,
> > R.Kano
> > 
> > 
> > 
> > ------------------------------------------------------------------------
> > 
> 
> 
> -- 
> 
> 
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> Dr. Leon Golub; Harvard-Smithsonian Center for Astrophysics
> 60 Garden Street, Cambridge MA 02138
> Ph: 617 495 7177; Fax: 617 496 7577
> e-mail: lgolub@cfa.harvard.edu
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