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OPTICAL TUBE ASSEMBLY

 
  1. What is the bare naked weight of the 20" OTA.....the 16"?
    16" is 140 pounds.
    20" is 190 pounds.


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  2. What are the outside dimensions of both of these OTAs:  diameter, total length?
    The OTA is not cylindrical, but basically the 16" is 21 inches in diameter and 33 inches long. The 20" is 25.7 inches in diameter and 40 inches long.

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  3. What is the backplate configuration for attaching accessories?  Similar most to the RCX or to the LX 200?
    The back plate configuration is identical to the existing LX200 16" back plate. It presents the standard rear cell thread (2.000-24). You can remove this adapter which gives the larger 4.000-16 thread.

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  4. Is there a control panel built into the back cell of the OTAs?
    The 16" and 20" OTA has a single 9-pin d-sub connector for attachment to the MAX saddle panel.

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  5. How many fans operate with the 20" / 16"
    There is one fan mounted on the 16" and 20" rear cover.

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  6. Are the fans pulling from a secondary filtered port such as the LX200-16?
    There is one fan mounted on the 16" and 20" rear cover.

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  7. Does the Max 20" and 16" have rear cell focusing and mirror lock OR is it all electronic as with the RCX telescope?
    All RCX fans push air into the OTA through the filter attached to the fan. It forces air through the OTA to the front where it exits around the corrector cell.

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  8. Is a dew heater system built into the front cell as with the RCX scopes?
    It is all electronic as with the other smaller RCX scopes. Mirror lock is not necessary since the pri mary is fixed in place. There is a huge advantage to computer controlled focusing, it is the ability to collimate with orthogonal control. What this means is you do not need to translate in your head how much you need to turn one of three screws on the old secondary collimation system. You simply hit the left/right or up/down buttons and collimation is achieved very quickly. Orthogonal control is very intuitive. Three point systems are not. Electronic collimation is essential on a large OTA's since it becomes a two person task. one looking through the scope, the other turning the hex wrench at the front of the OTA.

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  9. Is autocollimation via Autostar and the front lens provided as with the RCX scopes?
    Yes, just like it's smaller cousins.

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  10. Will focusing be achieved by moving the pri mary OR the secondary/corrector assembly?
    All the capabilities of the smaller RCX line is included with the larger 16" and 20" models.

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  11. Will optical coatings be the same on this OTA as with the RCX UHTC coatings or are new and more advanced coatings planned?
    Focusing is achieved the same way as the smaller RCX line, via the Autostar handbox moving the corrector/secondary assembly at the front of the OTA.

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  12. Are there provisions (i.e., 1/4-20 threaded holes) for attaching mounting plates, guide scopes, etc. on both top and bottom lengths of the OTA?
    The same threads are on RCX 16" and 20" that are on LX200 16". The mounting configuration limits access to only the top accessory holes. It is recommended that you use the wing plates provided on the saddle. These will place your accessories closer to the rotation axis so that you need less weight to balance.

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  13. What are the usable latitude ranges for the MAX mounting?
    MAX is capable of being adjusted to all latitudes. There are six bolts used to achieve one of three latitude ranges. 0 to 30; 30 to 60; and 60 to 90 degrees. There is overlap to allow for adjustment.


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  14. How is precise polar alignment achieved mechanically?
    Autostar will guide you through the necessary steps to mechanically polar align the mount using two adjustment knobs on the pedestal (wedge). Azimuth has +/- 8 degrees of adjustment.

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  15. What is the focal ratio of the MAX 20" / MAX 16?
    All RCX OTAs are f/8, which translates to a focal length of 128 inches (3251mm) for the 16" and 160 inches (4064mm) for the 20".

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  16. What is the clear aperture of the 20? / 16?
    Clear aperture is 16" for the 16" and 20" for the 20".

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  17. What is the actual mirror diameter of the 20"? / 16"?
    16" is 16.35 inches in diameter.
    20" is 20.60 inches in diameter.
    The larger mirror diameter helps with off-axis illumination.


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  18. What is the secondary mirror obstruction total diameter of the 20"? / 16"?
    16" is 5.7 inches = 35.6 percent.
    20" is 7.0 inches = 35.0 percent.
    Faster systems require larger secondaries for full field illumination.


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  19. What is the backfocus (distance in inches/cm) of the 20" / 16"?
    This is the distance from the SCT thread adapter most rear surface to the nominal focal plane:
    16" = 4.9 inches.
    20" = 4.2 inches.
    Note that the thread adapter is 0.70 inches thick. If you were to remove the thread adapter, the new dimensions would be:
    16" = 5.6 inches.
    20" = 4.9 inches.


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  20. What is the actual opening size of the rear cell opening port through which the optical light path passes?
    The light cone of course is a cone and changes diameter with position, but at the rear of the scope, with the thread adapter removed and looking at off-axis light at 1/2 degree per side (total 1 degree field of view):

    16" = 2.18 inches in diameter.
    20" = 2.72 inches in diameter.


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  21. What kind of coating is on the 16" and 20" optics?
    Meade's UHTC coatings are standard.

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Miscellaneous
 
  1. What mechanism allows for precise elevation adjustments for precise latitude setting?
    First of all, there are two linear bubble levels to level the assembly. Once level, there is a latitude scale. Dialing in your latitude using the latitude adjustment knob will get you close. Then Autostar will guide you through the fine adjustment.

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  2. What mechanism allows for azimuth adjustments to achieve proper E-W alignment to the North Celestial Pole?
    Using an azimuth adjustment knob, you have plus or minus eight degrees of adjustment in azimuth. Autostar routines guide you through the process of polar alignment using these two latitude & azimuth adjustment knobs.

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  3. What is the MAXIMUM payload of the MAX mount, NOT including counterweights?
    MAX is rated for 250 pounds (113 kilograms) of payload. It will take much more, but that is what we recommend.

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