2. Other

10 inch Refractor Renovation

The 10 inch D&G refractor was in need of some renovations. Please note: Amateur Astronomers of Pittsburgh own this telescope. I found issues with this telescope mount which was purchased new from Joe Nastasi at Parrallax Instruments. Joe did not fix theses issues and I continued an investigation on this matter. The organization spent $ 25,000 on this Parrallax HD 300 mount which is junk. Joe does not appear to be a man of his word to support his product. However the Amateur Astonomers of Pittsburgh decieded to have me expelled from the organization in my attempts to help them fix the problems encountered!! I do not support their organization any longer due to the politics of Tom Reiland of the AAAP.org or members of the organization who do not understand nor believe in the fairness that the telescopes & their appropiate mountings should work to a professional standard or be brought up to standard. Remember we spent 25K on this and it should work properly!! - Al Paslow
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  • With the tube assembly removed from the telescope we are now able to dismantle the scope. Larry McHenry begins work on the removal of the back plate.

    With the tube assembly removed from the telescope we are now able to dismantle the scope. Larry McHenry begins work on the removal of the back plate.

  • Some of the Members of the "dismantling crew".

    Some of the Members of the "dismantling crew".

  • Dan McKeel being impressed with the "big" 10 inch lens!

    Dan McKeel being impressed with the "big" 10 inch lens!

  • That's a really long tube!!

    That's a really long tube!!

  • Here the Parallax 300 C mount before tear-down. Notice - we discover that while the DEC shaft is made of beautiful stainless steel it is only an extension shaft. The true internal shafts are actually made of aluminium!

    Here the Parallax 300 C mount before tear-down. Notice - we discover that while the DEC shaft is made of beautiful stainless steel it is only an extension shaft. The true internal shafts are actually made of aluminium!

  • Tony inspects the equatorial head.

    Tony inspects the equatorial head.

  • This is the Declination shaft with the tapered roller bearing being removed from the race. Here is the first sign we may have possible deign concerns. The bearing is removed easy by hand. It is NOT pressed on. If the shaft had a small bearing at this end and a larger bearing at the other end, the bearings could be "pressed fitted" on the shaft and still provide the instrument that can be dismanted easily. However, theat would mandate the bearing you see now must face the opposite direction (ie tapered end pointing out NOT in as shown.) Tight clearances are obtained with the press fitting of bearings on shafts rather than simple setup pictured here. (See more about this later.)

    This is the Declination shaft with the tapered roller bearing being removed from the race. Here is the first sign we may have possible deign concerns. The bearing is removed easy by hand. It is NOT pressed on. If the shaft had a small bearing at this end and a larger bearing at the other end, the bearings could be "pressed fitted" on the shaft and still provide the instrument that can be dismanted easily. However, theat would mandate the bearing you see now must face the opposite direction (ie tapered end pointing out NOT in as shown.) Tight clearances are obtained with the press fitting of bearings on shafts rather than simple setup pictured here. (See more about this later.)

  • Removal of the Declination shaft from the aluminum housing.

    Removal of the Declination shaft from the aluminum housing.

  • Dan hams it up in front of the camera.

    Dan hams it up in front of the camera.

  • bearings after removal.

    bearings after removal.

  • A view of the gold anodized Byer's gear. Of note is that there appears to be a bearing made of deltrin or teflon material that is found of the inside bore of this gear. It apparently has been added as part of the clutch system or as a measure against the Byers gear galling against the aluminum declination shaft. Potential is the eventual "crushing" of the tape

    A view of the gold anodized Byer's gear. Of note is that there appears to be a bearing made of deltrin or teflon material that is found of the inside bore of this gear. It apparently has been added as part of the clutch system or as a measure against the Byers gear galling against the aluminum declination shaft. Potential is the eventual "crushing" of the tape

  • The declination shaft. interesting to note some items here. First the shaft comes together in two parts. First is the larger portion where the bearings fit. This is made of aluminum. The other part consists of a smaller shaft made of stainless steel that screws into the larger shaft. The stainless steel portion is the one that attaches to the counterweight system and everyone can see from the outside. The aluminum shaft appears to be of sloppy tolerance and bearing fit. There is a thin teflon disk which can be seen in this image which is against the large aluminum disk. This telfon disk also acts as a clutch. It has been determined by myself and confirmed by others that the shaft is 3 to 4 thousandths out of round at the bearing. This is unacceptable for astronomical purposes!! The telescope will bind in some spots and become too loose in others, depending on the moment arm of the telescope tube. Additionally the issue was resolved by Parrallax. This is a obvious problem with Joe Nastasi's machine work.

    The declination shaft. interesting to note some items here. First the shaft comes together in two parts. First is the larger portion where the bearings fit. This is made of aluminum. The other part consists of a smaller shaft made of stainless steel that screws into the larger shaft. The stainless steel portion is the one that attaches to the counterweight system and everyone can see from the outside. The aluminum shaft appears to be of sloppy tolerance and bearing fit. There is a thin teflon disk which can be seen in this image which is against the large aluminum disk. This telfon disk also acts as a clutch. It has been determined by myself and confirmed by others that the shaft is 3 to 4 thousandths out of round at the bearing. This is unacceptable for astronomical purposes!! The telescope will bind in some spots and become too loose in others, depending on the moment arm of the telescope tube. Additionally the issue was resolved by Parrallax. This is a obvious problem with Joe Nastasi's machine work.

  • The 9 ft long D&G tube fits neatly in Dans pickup. It will go to his shop for a complete repaint & repair job.

    The 9 ft long D&G tube fits neatly in Dans pickup. It will go to his shop for a complete repaint & repair job.

  • The tube in the tuck, hey it's a bit long ...but it fits!

    The tube in the tuck, hey it's a bit long ...but it fits!

  • looking down the housing.

    looking down the housing.

  • Here's the housing that contains the Dec. shaft. The design here is flawed in theory. It uses two taper roller bearings at each end of the shaft. That is good. The bad is the bearings are the same size. So if the bearings are the same size they can not be press fitted on the shaft for assembly purposes. Therefore there must be some play between the bearings and shaft - THAT IS BAD! If the front bearing would have been made smaller the bearing race could then be reversed and the entire shaft with bearings" pressed fitted" in place could have slid down into the housing you see here. The results would be tight and not sloppy. There is excessive clearances here to be a precision device.

    Here's the housing that contains the Dec. shaft. The design here is flawed in theory. It uses two taper roller bearings at each end of the shaft. That is good. The bad is the bearings are the same size. So if the bearings are the same size they can not be press fitted on the shaft for assembly purposes. Therefore there must be some play between the bearings and shaft - THAT IS BAD! If the front bearing would have been made smaller the bearing race could then be reversed and the entire shaft with bearings" pressed fitted" in place could have slid down into the housing you see here. The results would be tight and not sloppy. There is excessive clearances here to be a precision device.

  • the Parrallax name plate.

    the Parrallax name plate.

  • The dec housing showing the hub.

    The dec housing showing the hub.

  • The other side.

    The other side.

  • This housing contains the Byers gear.

    This housing contains the Byers gear.

  • aluminum tube welded to a flat disk. I believe the disk here about 14 inches in diameter. Note my alignment mark on the disk.

    aluminum tube welded to a flat disk. I believe the disk here about 14 inches in diameter. Note my alignment mark on the disk.

  • Close-up of the bearing race.

    Close-up of the bearing race.

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  • The housing here consists of basically a thick aluminum tube which has a portion milled to fit the large aluminum disk. I used a "silver sharpie" to mark where the equatorial mount head shown here bolts to its lower portion. The lower portion also has a silver sharpie mark to help with the re-installation. Line the top and bottom marks up and you have the proper orientation - no mistakes! This sharpie guide mark is visble in the above picture on the left side of the disk. When taking things apart always mark things you may question later and take lots of pictures!!

    The housing here consists of basically a thick aluminum tube which has a portion milled to fit the large aluminum disk. I used a "silver sharpie" to mark where the equatorial mount head shown here bolts to its lower portion. The lower portion also has a silver sharpie mark to help with the re-installation. Line the top and bottom marks up and you have the proper orientation - no mistakes! This sharpie guide mark is visble in the above picture on the left side of the disk. When taking things apart always mark things you may question later and take lots of pictures!!

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  • The Polar assembly is resting on a cart for the ease of moving it around.

    The Polar assembly is resting on a cart for the ease of moving it around.

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  • This is the plate that the hub that is attached to the Declination housing attaches to in the big mount.

    This is the plate that the hub that is attached to the Declination housing attaches to in the big mount.

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  • The Polar housing appears thin and hollow. I would not be supprised if it does not flex in various positions depending on the moment arm of the telescope tube. This can be strengthen and modified perhaps by bolting plates to the inside/outside once dismanted.

    The Polar housing appears thin and hollow. I would not be supprised if it does not flex in various positions depending on the moment arm of the telescope tube. This can be strengthen and modified perhaps by bolting plates to the inside/outside once dismanted.

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  • DEC housing. Thsi consisits of alumiunm tubing welded together. It should be checked for being "mechanically square" or "true" including aspects of the bore. Also this entire assemblyneeds to be orthogonal to the other axis and check appropiately.

    DEC housing. Thsi consisits of alumiunm tubing welded together. It should be checked for being "mechanically square" or "true" including aspects of the bore. Also this entire assemblyneeds to be orthogonal to the other axis and check appropiately.

  • You can see the aluminum shaft here with the teflon disk, that is used as a clutch.

    You can see the aluminum shaft here with the teflon disk, that is used as a clutch.

  • Here's a better picture of the declination shaft and both the aluminum part on right and the stainless steel portion on the left. The bearings fit on the aluminum.

    Here's a better picture of the declination shaft and both the aluminum part on right and the stainless steel portion on the left. The bearings fit on the aluminum.

  • This is the entire DEC shaft assembled- alumium and stainlesss shafts together.

    This is the entire DEC shaft assembled- alumium and stainlesss shafts together.

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    The declination shaft. interesting to note some items here. First the shaft comes together in two parts. First is the larger portion where the bearings fit. This is made of aluminum. The other part consists of a smaller shaft made of stainless steel that screws into the larger shaft. The stainless steel portion is the one that attaches to the counterweight system and everyone can see from the outside. The aluminum shaft appears to be of sloppy tolerance and bearing fit. There is a thin teflon disk which can be seen in this image which is against the large aluminum disk. This telfon disk also acts as a clutch. It has been determined by myself and confirmed by others that the shaft is 3 to 4 thousandths out of round at the bearing. This is unacceptable for astronomical purposes!! The telescope will bind in some spots and become too loose in others, depending on the moment arm of the telescope tube. Additionally the issue was resolved by Parrallax. This is a obvious problem with Joe Nastasi's machine work.
    The 9 ft long D&G tube fits neatly in Dans pickup. It will go to his shop for a complete repaint & repair job.
    The tube in the tuck, hey it's a bit long ...but it fits!