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cildarithModerator
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Reged: 08/26/04
Posts: 2651
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Re: Sketching close double stars new [Re: cildarith]
      #680798 - 11/10/05 11:39 AM Attachment (71 downloads)

The next step is to place a white matt around the image:

Attachment

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Eric
6" f/6 Parks Newtonian
10x50 Bushnell Binocs


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cildarithModerator
Carpal Tunnel


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Re: Sketching close double stars new [Re: cildarith]
      #680799 - 11/10/05 11:40 AM Attachment (75 downloads)

And invert. For many this would be an appropriate place to stop, but for some reason I always feel compelled to keep going, though this is the stage that probably best represents the view through the eyepiece:

Attachment

--------------------
Eric
6" f/6 Parks Newtonian
10x50 Bushnell Binocs


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cildarithModerator
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Reged: 08/26/04
Posts: 2651
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Re: Sketching close double stars new [Re: cildarith]
      #680803 - 11/10/05 11:41 AM Attachment (82 downloads)

Next (and I finally get around to answering your question, John) I add the halos around the brighter stars in white (a "primer", if you will). I use the airbrush setting, white "paint" and the transparency set at 60% for the inner ring, 70% for the second ring, and 80% for the third ring. For the first ring I select my third largest brush size and click on the center of the star image once for an 11th magnitude star, twice for a 10th magnitude, three times for a 9th magnitude, and so on. For the second halo I select the second largest brush size and click on the center of the star image once for an 8th magnitude star, twice for a 7th magnitude star, and so on. A third halo may be added to stars of fifth magnitude and brighter (there are none in this example) using the largest brush in the same manner. For stars of 2nd magnitude and brighter I'll add the diffraction spikes that become visible at about that magnitude in my scope:

Attachment

--------------------
Eric
6" f/6 Parks Newtonian
10x50 Bushnell Binocs


CN Sketch Gallery||MinDat Mineral Gallery


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cildarithModerator
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Reged: 08/26/04
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Re: Sketching close double stars new [Re: cildarith]
      #680806 - 11/10/05 11:42 AM Attachment (73 downloads)

The next step involves adding color to the disks in exactly the same manner as outlined above, but with transparencies set at 70% for the first disk, 80% for the second and 90% for the third:

Attachment

--------------------
Eric
6" f/6 Parks Newtonian
10x50 Bushnell Binocs


CN Sketch Gallery||MinDat Mineral Gallery


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cildarithModerator
Carpal Tunnel


Reged: 08/26/04
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Re: Sketching close double stars new [Re: cildarith]
      #680809 - 11/10/05 11:43 AM Attachment (75 downloads)

Finally, I burn in the centers of each of the star disks, first with my fourth largest brush, white paint, 50% transparency and one click per magnitude above 12. Then I repeat the processes with the fifth largest brush (which at this point is working on a single pixel):

Attachment

--------------------
Eric
6" f/6 Parks Newtonian
10x50 Bushnell Binocs


CN Sketch Gallery||MinDat Mineral Gallery


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Faith_J
Sketcher Extraordinaire


Reged: 11/17/04
Posts: 5830
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Re: Sketching close double stars new [Re: cildarith]
      #680813 - 11/10/05 11:44 AM

Eric, many thanks for the tutorial and sharing the secret of your stunning double star drawings.

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Visual deep sky

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Jeremy Perez
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Reged: 08/12/04
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Re: Sketching close double stars new [Re: Faith_J]
      #680909 - 11/10/05 12:49 PM

Eric, I had no idea you had such an excellent system set up for these. A huge thanks for spelling it out for us. By doing it that way, you've really provided a consistent way to convey magnitudes, and they look stunning in the process. I haven't been anywhere near as systematic in my approach. You're inspiring me to re-examine the attention I give to star magnitudes at the eyepiece.

Thanks!

--------------------

Orion SVP 6LT (6" f/8 Newt) || Orion XT8 (8" f/5.9 Dob) || 15x70 Oberwerk Binoculars || Coronado PST
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cildarithModerator
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Re: Sketching close double stars new [Re: Jeremy Perez]
      #680972 - 11/10/05 01:49 PM

Faith, you're most welcome. I hope you find some part of it to be useful.

Jeremy, glad to be of service! I've been attempting to improve my observing "protocol" by following (well, sort of) the advice in the Webb Society Handbooks on "Recording Observations." Estimating the magnitudes of significant field stars is part of that systematic process so I'm trying to do more of that lately. Thus far I only trust myself to an accuracy of about a half-magnitude or so...

--------------------
Eric
6" f/6 Parks Newtonian
10x50 Bushnell Binocs


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Jeremy Perez
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Re: Sketching close double stars new [Re: cildarith]
      #681068 - 11/10/05 02:47 PM

So...

There I was
...there I was
......there I was...
At the Webb Society handbooks page.

when I notice a number of potentially tasty treats--some of which are out of print, but also appear to be readily available at a certain online book seller. Which book/books were you possibly referring to?

Thanks kindly

--------------------

Orion SVP 6LT (6" f/8 Newt) || Orion XT8 (8" f/5.9 Dob) || 15x70 Oberwerk Binoculars || Coronado PST
The Belt Of Venus || Sketch Gallery || Sketching Resources || Drawn to the Universe Column


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cildarithModerator
Carpal Tunnel


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Re: Sketching close double stars new [Re: Jeremy Perez]
      #681092 - 11/10/05 03:02 PM

If I remember correctly that section was included at the beginning of each of the first five volumes (the only ones I've seen; which are out of print, sadly). I never owned any of these, but the university library had a set which I enjoyed perusing. I hand-copied the observing procedure into one of my notebooks one day between classes (as I didn't have a dime to feed the Xerox machine...)

Perhaps Faith can give you more specific information...

--------------------
Eric
6" f/6 Parks Newtonian
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Jeremy Perez
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Re: Sketching close double stars new [Re: cildarith]
      #681175 - 11/10/05 04:02 PM

Heheh, yes, I was getting ready to page Faith myself. I was trying to find the Introduction to Visual Deep-Sky Observing book at [online bookseller]'s site, and couldn't find it there...

<<edit>> nevermind, I found how to order it directly from the Webb society...

--------------------

Orion SVP 6LT (6" f/8 Newt) || Orion XT8 (8" f/5.9 Dob) || 15x70 Oberwerk Binoculars || Coronado PST
The Belt Of Venus || Sketch Gallery || Sketching Resources || Drawn to the Universe Column


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HAC
professor emeritus


Reged: 04/07/05
Posts: 534
Re: Sketching close double stars new [Re: cildarith]
      #681255 - 11/10/05 05:22 PM

Hey Eric,

Thank you very much for taking the time for such a detailed explanation - very much appreciated.

Take care,
john

--------------------
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Faith_J
Sketcher Extraordinaire


Reged: 11/17/04
Posts: 5830
Loc: South coast of England
Re: Sketching close double stars new [Re: cildarith]
      #681269 - 11/10/05 05:33 PM

Quote:

After the sketch has been scanned into the computer I flatten the field by increasing the brightness by 20%. This wasn't really necessary for this particular sketch, but if your scanner produces a band of shadow on half the image, or your page has been adversely affected by dew this is an effective way to eliminate these artifacts:




That's interesting to know, Eric, because my scanner sometimes produces a shadow on the image. I've ended up spending ages with the eraser tool trying to get rid of it. It sounds like you've come up with a better way of getting rid of it.

--------------------
Visual deep sky

18" f4.3 dob
7.9" f/4 Celestron Newtonian
8x42 binos
100% visual observing...


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cildarithModerator
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Reged: 08/26/04
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Re: Sketching close double stars new [Re: Faith_J]
      #681385 - 11/10/05 07:12 PM

John, you're most welcome!

Faith, my scanner does this occasionally as well (I've no idea what causes it). Proceed with caution here on scans of nebulous objects because you may end up with what Jeremy calls 'clipped highlights' (see his post on Optimizing Sketches for the Web), so don't brighten any more than necessary with these types of object. I will happily settle for a little clipping to eliminate those pesky shadows though!

I've tried the eraser method too. Definitely not worth the trouble!

--------------------
Eric
6" f/6 Parks Newtonian
10x50 Bushnell Binocs


CN Sketch Gallery||MinDat Mineral Gallery


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HAC
professor emeritus


Reged: 04/07/05
Posts: 534
Re: Sketching close double stars new [Re: cildarith]
      #681775 - 11/11/05 12:04 AM

Greetings all,

I just wanted to acknowledge Eric's work and thank everyone who contributes to these types of exchanges. What a wonderful resource for those who actually view and wish to account for their activities. Tremendous! What a thrill! And what a useful resource!

Take care all,
john

--------------------
Bring Back The AP Waiting List Thread and Let Freedom Ring


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