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Re: [ccd-newastro] Messier 16, Eagle Nebula

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  • Ron Wodaski
    Two telescopes with the same image scale are not necessarily the same. In your case, the difference is in aperture. There are definite benefits to more
    Message 1 of 9 , Mar 8, 2013
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      Two telescopes with the same image scale are not necessarily the same. In your case, the difference is in aperture. There are definite benefits to more aperture!

      This is because a larger aperture collects more light - as Stan points out, that means each pixel gets more photons, and thus the SNR is improved.

      So even if they both would have the same image scale, the larger aperture would provide better data, or the same data in less time.

      Ron Wodaski



      On Mar 7, 2013, at 2:18 PM, jfmiller7@... wrote:

      >
      >
      > So are the options to use a smaller chipped camera, or to crop the image (assuming the resolution is there)?
      >
      >
      >
      > On a somehat related note, I am considering the advantages of adding a longer focal length scope like the 12.5" Planewave to my current STL-11000 vs. adding a smaller chipped camera with smaller pixels (8300) to a 6" refcractor. I elaize normally aperture wins on the resolution front, but what about these two options? Seems that the pixcells per arcsecond are about the same.
      >
      >
      >
      > Sorry for getting off topic on the original image.
      >
      >
      >
      > thanks,
      >
      >
      >
      > Jim
      >
      > ----- Original Message -----
      >
      >
      >
      >
      > From: "Stan" < stan _ ccd @...>
      > To: ccd -newastro@ yahoogroups .com
      > Sent: Wednesday, March 6, 2013 10:55:52 AM
      > Subject: [ ccd -newastro] Re: Messier 16, Eagle Nebula
      >
      >
      >
      >
      >
      >
      > --- " barry . schellenberg " wrote:
      >> ... 17" Planewave telescope with FLI PL6303E CCD ...
      >> http :// astromarina . zenfolio .com/p81839294/h57086EDC#h57086edc
      >> I am open to criticism...
      >
      > OK, I'll get the "nice image" kudo out of the way and get to the criticism . It is a nice image and has many good things going for it. But that target is a very popular object and those images do not especially stand out.
      >
      > When I read "17 inch Planewave " I got excited to anticipate what it could do with the "pillars of creation" but was disappointed by yet another low-res/wide-field pic. Maybe the data has much better resolution than the display pix but those display images could have (and have) been made with a small refractor . I was expecting something that might challenge an image I made several (12.5!) years ago with a 14.5" RCOS :
      >
      > http :// www . stanmooreastro .com/M16. html
      >
      > Colorizing that target is a complete waste of time and effort. It's nothing but RED! That redness inhibits eye/mind ability to discern subtle contrasts and IMHO contributes nothing other than appeasing the color mafia. To your credit you do also show a monochrome pic but the tonalities are very harsh and waste monochrome's potential to reveal subtle contrasts. But I suppose that is all a matter of taste.
      >
      > Stan
      >
      >
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      >
      > [Non-text portions of this message have been removed]
      >
      >
      >
      > ------------------------------------
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    • jfmiller7
      Thanks very much for the info Stan. You are pretty close, the refractor is an F 7.3 ( TOA --150). I cannot afford to keep both the TOA and Planewave , so i
      Message 2 of 9 , Mar 9, 2013
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        Thanks very much for the info Stan. You are pretty close, the refractor is an F 7.3 ( TOA --150). I cannot afford to keep both the TOA and Planewave , so i need to choose :-) 

        thanks again,

         

        Jim 

        ----- Original Message -----




        From: "Stan" < stan _ ccd @...>
        To: ccd -newastro@ yahoogroups .com
        Sent: Friday, March 8, 2013 12:18:21 PM
        Subject: [ ccd -newastro] Re: Messier 16, Eagle Nebula

         




        > ... those paths are very different, both in terms of efforts
        > required and results obtained...

        Although, your original configurations is less different because the Planewave /11k and refractor /8300 would have similar image scales. So the scope/cameras would generally produce similar resolution, though the Planewave should be superior most of the time. And the Planewave would produce greatly enhanced S/N because it collects 4x more photons/sec than the refractor . So even if you are not that interested in hi-res the Planewave is still worthy of consideration.

        Stan




        [Non-text portions of this message have been removed]
      • barry.schellenberg
        Stan, Thank you for your comments. I appreciate your point of view. I agree with your assesment of the disappointing wide field view this scope and camera
        Message 3 of 9 , Mar 9, 2013
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          Stan,

          Thank you for your comments. I appreciate your point of view. I agree with your assesment of the disappointing wide field view this scope and camera combination present. I too was hoping for a more detailed close up.

          If you click on the top of my image where is says "Download", you will be able to zoom and view more of the subtle details. http://astromarina.zenfolio.com/p264248004/h57096E86#h57096e86

          Perhaps I could have displayed a cropped version to gain that effect to begin with. Keep in mind this is also only 125 total minutes of aquisition time. It could certainly use more.

          Let me know what you think after you download and view the original image size and zoom in.

          Best regards,
          Barry


          --- In ccd-newastro@yahoogroups.com, "Stan" <stan_ccd@...> wrote:
          >
          > --- "barry.schellenberg" <barryschellenberg@> wrote:
          > > ... 17" Planewave telescope with FLI PL6303E CCD ...
          > > http://astromarina.zenfolio.com/p81839294/h57086EDC#h57086edc
          > > I am open to criticism...
          >
          > OK, I'll get the "nice image" kudo out of the way and get to the criticism <g>. It is a nice image and has many good things going for it. But that target is a very popular object and those images do not especially stand out.
          >
          > When I read "17 inch Planewave" I got excited to anticipate what it could do with the "pillars of creation" but was disappointed by yet another low-res/wide-field pic. Maybe the data has much better resolution than the display pix but those display images could have (and have) been made with a small refractor. I was expecting something that might challenge an image I made several (12.5!) years ago with a 14.5" RCOS:
          >
          > http://www.stanmooreastro.com/M16.html
          >
          > Colorizing that target is a complete waste of time and effort. It's nothing but RED! That redness inhibits eye/mind ability to discern subtle contrasts and IMHO contributes nothing other than appeasing the color mafia. To your credit you do also show a monochrome pic but the tonalities are very harsh and waste monochrome's potential to reveal subtle contrasts. But I suppose that is all a matter of taste.
          >
          > Stan
          >
        • Stan
          ... That s better, though the display is still a bit too undersampled (reduced) for my taste. But it does begin to reveal the resolution limit. Did you try
          Message 4 of 9 , Mar 10, 2013
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            --- "barry.schellenberg" <barryschellenberg@...> wrote:
            > ... click on the top of my image where is says "Download"
            > http://astromarina.zenfolio.com/p264248004/h57096E86#h57096e86

            That's better, though the display is still a bit too undersampled (reduced) for my taste. But it does begin to reveal the resolution limit. Did you try deconvolution on the original? The short-exp S/N may be too thin to support significant deconvolution but it's worth a try.

            Stan
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