Adding a Barlow to my C11

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1jimalexander United States of America
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Adding a Barlow to my C11

#1

Post by 1jimalexander »


I set up my camera at the proper focal length including an off axis guider.
I've added a ZWO ADC.
I have a 2x Barlow (1.25 slip fit both ends) that I'd like to include.
Can some one explain how I might include this Barlow in this set-up?
What are the back focus considerations for the ADC and the Barlow?
Thank you,
Jim
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c11.jpg
    Scope: Skywatcher Esprit 150 Super APO, Celestron C11 Edge HD
    Mount: Celestron CGX-L, Ioptron CEM70G
    Cameras: ATIK 11000 mono ,ASI224MC, ASI533MC
    Filtering: ATIK EFW2 Astronomik LRGB, Ha, s2, O3 (12nm) Optolong L-eXtreme
    Guiding: Orion mini 50 mm, Orion Starshoot, PHD ,Primalucelab 60mm scope, Celestron OAG with ASI290mm mini
    Polar align: PoleMaster, Ipolar
    Software:SGP, Starry Night Pro, PS, PI
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    JayTee United States of America
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    Re: Adding a Barlow to my C11

    #2

    Post by JayTee »


    What is the primary purpose of this new setup? Is it for planetary Imaging or very small deep sky imaging?

    If your object is planetary Imaging I would remove the off axis guider and I would put the barlow after the ADC. So the barlow goes between the ADC and the camera itself.

    If your goal is very small deep sky objects, this is an area where I don't have the knowledge you need. It might require some experimentation on your part.
    ∞ Primary Scopes: #1: Celestron CPC1100 #2: 8" f/7.5 Dob #3: CR150HD f/8 6" frac
    ∞ AP Scopes: #1: TPO 6" f/9 RC #2: ES 102 f/7 APO #3: ES 80mm f/6 APO
    ∞ G&G Scopes: #1: Meade 102mm f/7.8 #2: Bresser 102mm f/4.5
    ∞ Guide Scopes: 70 & 80mm fracs -- The El Cheapo Bros.
    ∞ Mounts: iOptron CEM70AG, SW EQ6, Celestron AVX, SLT & GT (Alt-Az), Meade DS2000
    ∞ Cameras: #1: ZWO ASI294MC Pro #2: 662MC #3: 120MC, Canon T3i, Orion SSAG, WYZE Cam3
    ∞ Binos: 10X50,11X70,15X70, 25X100
    ∞ EPs: ES 2": 21mm 100° & 30mm 82° Pentax XW: 7, 10, 14, & 20mm 70°

    Searching the skies since 1966. "I never met a scope I didn't want to keep."

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    Re: Adding a Barlow to my C11

    #3

    Post by 1jimalexander »


    I am doing moon and planetary at the moment so I guess I don't need the off axis guider.
    How do I attach the barlow? I suppose I'll screw a 1.25 adapter into the camera for that end but what about the connection to the ADC?
    How does all this figure into the back focus?
      Scope: Skywatcher Esprit 150 Super APO, Celestron C11 Edge HD
      Mount: Celestron CGX-L, Ioptron CEM70G
      Cameras: ATIK 11000 mono ,ASI224MC, ASI533MC
      Filtering: ATIK EFW2 Astronomik LRGB, Ha, s2, O3 (12nm) Optolong L-eXtreme
      Guiding: Orion mini 50 mm, Orion Starshoot, PHD ,Primalucelab 60mm scope, Celestron OAG with ASI290mm mini
      Polar align: PoleMaster, Ipolar
      Software:SGP, Starry Night Pro, PS, PI
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      Re: Adding a Barlow to my C11

      #4

      Post by 1jimalexander »


      Here's some pics of what I'm working with less the AOG and the extensions for achieving the 146mm back focus.
      Also, a pic of the adapters I currently have.
      Attachments
      IMG_4548.JPG
      IMG_4549.JPG
        Scope: Skywatcher Esprit 150 Super APO, Celestron C11 Edge HD
        Mount: Celestron CGX-L, Ioptron CEM70G
        Cameras: ATIK 11000 mono ,ASI224MC, ASI533MC
        Filtering: ATIK EFW2 Astronomik LRGB, Ha, s2, O3 (12nm) Optolong L-eXtreme
        Guiding: Orion mini 50 mm, Orion Starshoot, PHD ,Primalucelab 60mm scope, Celestron OAG with ASI290mm mini
        Polar align: PoleMaster, Ipolar
        Software:SGP, Starry Night Pro, PS, PI
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        Re: Adding a Barlow to my C11

        #5

        Post by JayTee »


        Starting from the telescope side, I would put the ADC on followed by the barlow slipped into a 1.25 inch nose piece on the camera. You have a C11 which means it will come to focus since you're not worried about the periphery FOV because you're doing planetary imaging, so back focus isn't quite so much an issue.

        When I do planetary Imaging I put a Crayford 2-speed focuser on the back of my C11 even though I have a FeatherTouch focuser for normal focus. I set the Crayford to the middle of its travel then focus with the FeatherTouch on the C11, then fine tune the focus with the Crayford. I will even mess with focus in the middle of a video if things seem to be going quite fuzzy.
        ∞ Primary Scopes: #1: Celestron CPC1100 #2: 8" f/7.5 Dob #3: CR150HD f/8 6" frac
        ∞ AP Scopes: #1: TPO 6" f/9 RC #2: ES 102 f/7 APO #3: ES 80mm f/6 APO
        ∞ G&G Scopes: #1: Meade 102mm f/7.8 #2: Bresser 102mm f/4.5
        ∞ Guide Scopes: 70 & 80mm fracs -- The El Cheapo Bros.
        ∞ Mounts: iOptron CEM70AG, SW EQ6, Celestron AVX, SLT & GT (Alt-Az), Meade DS2000
        ∞ Cameras: #1: ZWO ASI294MC Pro #2: 662MC #3: 120MC, Canon T3i, Orion SSAG, WYZE Cam3
        ∞ Binos: 10X50,11X70,15X70, 25X100
        ∞ EPs: ES 2": 21mm 100° & 30mm 82° Pentax XW: 7, 10, 14, & 20mm 70°

        Searching the skies since 1966. "I never met a scope I didn't want to keep."

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        Re: Adding a Barlow to my C11

        #6

        Post by 1jimalexander »


        Thank you. I have the oem focuser but I have purchased the ZWO EAF for auto focusing (not installed yet). How might that compare to the fine focusing compared to the 2 speed Crayford. I'm just getting started with the C11. I've had the same image train on my 6" refractor for years so I'm not used to dealing with the SCT. Perhaps auto focus is not useful for planetary?
        I will look into your suggested scope/ADC/Barlow/camera sequence. I'm using an ASI533MC camera and need to figure out how to attach the 1.25 nose piece to the camera.
          Scope: Skywatcher Esprit 150 Super APO, Celestron C11 Edge HD
          Mount: Celestron CGX-L, Ioptron CEM70G
          Cameras: ATIK 11000 mono ,ASI224MC, ASI533MC
          Filtering: ATIK EFW2 Astronomik LRGB, Ha, s2, O3 (12nm) Optolong L-eXtreme
          Guiding: Orion mini 50 mm, Orion Starshoot, PHD ,Primalucelab 60mm scope, Celestron OAG with ASI290mm mini
          Polar align: PoleMaster, Ipolar
          Software:SGP, Starry Night Pro, PS, PI
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          Re: Adding a Barlow to my C11

          #7

          Post by 1jimalexander »


          JayTee, I've purchased the Crayford dual speed. I'm still unclear about back focus. How does the Crayford impact back focus? You say "back focus isn't quite so much an issue". Do I still need to deal with the 146mm?
          Thanks, Jim
            Scope: Skywatcher Esprit 150 Super APO, Celestron C11 Edge HD
            Mount: Celestron CGX-L, Ioptron CEM70G
            Cameras: ATIK 11000 mono ,ASI224MC, ASI533MC
            Filtering: ATIK EFW2 Astronomik LRGB, Ha, s2, O3 (12nm) Optolong L-eXtreme
            Guiding: Orion mini 50 mm, Orion Starshoot, PHD ,Primalucelab 60mm scope, Celestron OAG with ASI290mm mini
            Polar align: PoleMaster, Ipolar
            Software:SGP, Starry Night Pro, PS, PI
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            JayTee United States of America
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            Re: Adding a Barlow to my C11

            #8

            Post by JayTee »


            The idea of correct back focus is to place optical accessories your FF, FR, and focal reducer at the correct distance to get the greatest benefit of that accessory to put a "corrected" image on the camera sensor. The benefit you are looking for is a flat image across the entire FOV.

            In planetary imaging our concern is with the center 1/3 of the FOV. As long as we can bring the planet into focus that's all you need to worry about. Placing a barlow in the optical path does not change your approach just bring it into focus.

            If you have not read this article please do it does a very good job of explaining back focus.

            https://agenaastro.com/articles/miscell ... %20shallow.
            ∞ Primary Scopes: #1: Celestron CPC1100 #2: 8" f/7.5 Dob #3: CR150HD f/8 6" frac
            ∞ AP Scopes: #1: TPO 6" f/9 RC #2: ES 102 f/7 APO #3: ES 80mm f/6 APO
            ∞ G&G Scopes: #1: Meade 102mm f/7.8 #2: Bresser 102mm f/4.5
            ∞ Guide Scopes: 70 & 80mm fracs -- The El Cheapo Bros.
            ∞ Mounts: iOptron CEM70AG, SW EQ6, Celestron AVX, SLT & GT (Alt-Az), Meade DS2000
            ∞ Cameras: #1: ZWO ASI294MC Pro #2: 662MC #3: 120MC, Canon T3i, Orion SSAG, WYZE Cam3
            ∞ Binos: 10X50,11X70,15X70, 25X100
            ∞ EPs: ES 2": 21mm 100° & 30mm 82° Pentax XW: 7, 10, 14, & 20mm 70°

            Searching the skies since 1966. "I never met a scope I didn't want to keep."

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            Re: Adding a Barlow to my C11

            #9

            Post by 1jimalexander »


            Soooooo....could I expect to insert my ASI224MC into the visual back and be able to achieve focus?
            Thanks for the link. It helps but I'm still not there.
            Jim
              Scope: Skywatcher Esprit 150 Super APO, Celestron C11 Edge HD
              Mount: Celestron CGX-L, Ioptron CEM70G
              Cameras: ATIK 11000 mono ,ASI224MC, ASI533MC
              Filtering: ATIK EFW2 Astronomik LRGB, Ha, s2, O3 (12nm) Optolong L-eXtreme
              Guiding: Orion mini 50 mm, Orion Starshoot, PHD ,Primalucelab 60mm scope, Celestron OAG with ASI290mm mini
              Polar align: PoleMaster, Ipolar
              Software:SGP, Starry Night Pro, PS, PI
              ASIAIR Plus
              Ultimate PowerBox v2
              User avatar
              JayTee United States of America
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              Re: Adding a Barlow to my C11

              #10

              Post by JayTee »


              You bet, just plug your camera into the back of your C11 and bring it to focus and that's all you need to do. Or put your camera into the Barlow and put the Barlow in the visual back of your C11 and that's another way to do it. Or hook up your crayford dual speed put the Barlow and the camera together and slide those into the crayford you can do it that way too.

              I have a picture around here somewhere that illustrates what I'm saying. Give me a few, I'm trying to find it.
              ∞ Primary Scopes: #1: Celestron CPC1100 #2: 8" f/7.5 Dob #3: CR150HD f/8 6" frac
              ∞ AP Scopes: #1: TPO 6" f/9 RC #2: ES 102 f/7 APO #3: ES 80mm f/6 APO
              ∞ G&G Scopes: #1: Meade 102mm f/7.8 #2: Bresser 102mm f/4.5
              ∞ Guide Scopes: 70 & 80mm fracs -- The El Cheapo Bros.
              ∞ Mounts: iOptron CEM70AG, SW EQ6, Celestron AVX, SLT & GT (Alt-Az), Meade DS2000
              ∞ Cameras: #1: ZWO ASI294MC Pro #2: 662MC #3: 120MC, Canon T3i, Orion SSAG, WYZE Cam3
              ∞ Binos: 10X50,11X70,15X70, 25X100
              ∞ EPs: ES 2": 21mm 100° & 30mm 82° Pentax XW: 7, 10, 14, & 20mm 70°

              Searching the skies since 1966. "I never met a scope I didn't want to keep."

              Image
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