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49061RE: [ccd-newastro] Zone book

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  • Wodaski Yahoo
    Jan 11, 2006
    • 0 Attachment
      Our layout person is out on medical leave until later this month. Her fiancé
      was very ill - was in intensive care for most of December.

      We have most of the chapters ready to go, but when she gets back, we'll wrap
      up the layout and editing on the few remaining chapters and send the book
      off to the printer.


      Ron Wodaski
      http://www.newastro.com


      -----Original Message-----
      From: ccd-newastro@yahoogroups.com [mailto:ccd-newastro@yahoogroups.com] On
      Behalf Of Chris Curran
      Sent: Wednesday, January 11, 2006 6:30 AM
      To: ccd-newastro@yahoogroups.com
      Subject: [ccd-newastro] Zone book

      Ron,

      You must have missed this in the noise... What's the status of the
      Zone book?

      Chris

      --- In ccd-newastro@yahoogroups.com, "Chris Curran"
      <curran.chris@g...> wrote:
      >
      > Ron,
      >
      > You need to update your page - it states that it is scheduled for Dec
      > 2005 release - obviously that didn't happen. Any new news on a new
      > release date?
      >
      > Chris
      >
      > --- In ccd-newastro@yahoogroups.com, "Wodaski Yahoo" <yahoo@w...> wrote:
      > >
      > > Sorry for the late reply - I had a major server crash and this email
      > message
      > > got lost in the shuffle.
      > >
      > > Anyone interested in the new book can get information here:
      > >
      > > http:/www.newastro.com/ipb
      > >
      > >
      > > Ron Wodaski
      > > http://www.newastro.com
      > >
      > >
      > > -----Original Message-----
      > > From: ccd-newastro@yahoogroups.com
      > [mailto:ccd-newastro@yahoogroups.com] On
      > > Behalf Of Dale
      > > Sent: Saturday, December 31, 2005 11:14 PM
      > > To: ccd-newastro@yahoogroups.com
      > > Subject: [ccd-newastro] Re: A colorful cluster of stars
      > >
      > > What is the title and where can I purchase your book that covers
      > > Zone processing. I own your privious book and it has been
      > > instumental in my learning process. I would Love to get your newest
      > > book.
      > >
      > > --- In ccd-newastro@yahoogroups.com, "Wodaski Yahoo"
      > > <yahoo@w...> wrote:
      > > >
      > > > "Modify, Expand and Feather" is shorthand for a series of
      > > techniques that
      > > > are part of the zone system. The idea is to use Select | Modify |
      > > Expand to
      > > > enlarge the selection of the stars (the making of which is a whole
      > > other
      > > > topic) so that you pick up a little background around the stars.
      > > The amount
      > > > will vary with your image scale, quality of optics, the seeing on
      > > a given
      > > > night, etc. Feathering is usually 25 to 75% of the expansion, and
      > > again the
      > > > amount varies with the circumstances of the image and conditions.
      > > >
      > > > This is covered in detail in the new book on the Zone System;
      > > there is an
      > > > entire chapter just on star selection. It gets more complicated
      > > than one
      > > > would imagine; there is no simple answer of so many pixels - one
      > > has to
      > > > learn to make judgments based on your data and your equipment.
      > > >
      > > >
      > > > Ron Wodaski
      > > > http://www.newastro.com
      > > >
      > > >
      > > > -----Original Message-----
      > > > From: ccd-newastro@yahoogroups.com [mailto:ccd-
      > > newastro@yahoogroups.com] On
      > > > Behalf Of nraider217@c...
      > > > Sent: Saturday, December 31, 2005 2:09 AM
      > > > To: ccd-newastro@yahoogroups.com
      > > > Subject: Re: [ccd-newastro] A colorful cluster of stars
      > > >
      > > > Thanks for the info on this image, as preserving star colors has
      > > been
      > > > difficult for me at times. In the image processing where you spoke
      > > of the
      > > > manner in which you sharpened your star images , you stated to
      > > remember to
      > > > "Modify, Expand and Feather' before you apply the unsharp
      > > masking. Could
      > > > you please share, how much to expand the selection ( 1
      > > pixel ?) , and the
      > > > proper way to feather prior to applying the sharpening filter.
      > > Thanks
      > > > again.
      > > >
      > > Dale
      > > >
      > > > -------------- Original message --------------
      > > > From: "Ron Wodaski" <yahoo@w...>
      > > > I don't get many opportunities to image these days, but I was
      > > testing
      > > > hardware last night and took enough images to actually make
      > > something nice.
      > > > <G>
      > > >
      > > > This is an image of the open cluster NGC 1245, taken with the 20"
      > > RC. The
      > > > seeing was pretty soft, so I made the most of it by imaging binned
      > > 2x2 and
      > > > using short exposure time to avoid saturating most of the stars
      > > (this helps
      > > > preserve star color). I increased saturation somewhat to make the
      > > star
      > > > colors more obvious:
      > > >
      > > > http://www.bb-obs.com/img/rc20/11000/NGC_1245_RGB_2b.jpg
      > > >
      > > > Here are some tips for getting good star color in cluster images:
      > > >
      > > > * Poor seeing can actually be your friend, and you can get the same
      > > > advantages by going slightly out of focus. The idea is to spread
      > > the
      > > > starlight out a bit, and avoid a saturated core for most of the
      > > stars. You
      > > > can use some careful unsharp masking to tighten the stars up if
      > > the soft
      > > > look doesn't work for you. This image is a 50-50 mix of a soft
      > > image and a
      > > > sharpened image.
      > > >
      > > > * Keep your exposure times fairly short. Even if you are using an
      > > ABG
      > > > camera, star cores will saturate quite easily. You'll need to
      > > strike a
      > > > balance between exposures short enough to avoid saturation on most
      > > stars,
      > > > but long enough to capture the dimmer stars.
      > > >
      > > > * When processing, use a very compressed Curve in Photoshop. The
      > > curve
      > > > should be sharp at the left (dark) end, and flat for 75% or more
      > > of the rest
      > > > of the curve. The idea is to boost dim areas while NOT compressing
      > > the
      > > > bright areas very much. If you compress the bright stuff (with a
      > > curve that
      > > > isn't mostly flat) too much, the star cores will saturate (clip,
      > > or close to
      > > > it) and you will lose that color you wanted.
      > > >
      > > > * You might want to try sharpening in two steps: select just the
      > > brightest
      > > > stars with Color Range (maybe half to two thirds of all the
      > > stars), and
      > > > apply a moderate sharpening (1.0 - 1.7, 50% amount, zero
      > > threshold), and
      > > > then select as many stars as you can and apply a light sharpening
      > > (0.6 to
      > > > 1.0). Remember to modify/expand and then feather before you apply
      > > the
      > > > filter.
      > > >
      > > > * The background will likely need smoothing because of high read
      > > noise due
      > > > to short exposure times.
      > > >
      > > >
      > > > Ron Wodaski
      > > > http://www.newastro.com <http://www.newastro.com/>
      > > >
      > > >
      > > >
      > > >
      > > >
      > > >
      > > > [Non-text portions of this message have been removed]
      > > >
      > > >
      > > >
      > > >
      > > >
      > > >
      > > >
      > > >
      > > >
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      > > >
      > > >
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