C8 POLAR ALIGNMENT PROBLEMS?

If you own a standard Celstar C8 telescope you are aware of the problems that arise when trying to properly polar align it. First the tripod has to be perfectly level which requires shims under the legs since the legs are nonadjustable. Next is the problem of adjusting the azimuth. The entire tripod has to be shifted right or left however many times is necessary to align using the two star drift method. Once moved you will have to relevel each and every time. The wedgepod has latitude adjusters which have to be accurately set to the lattitude of your viewing site. As you well know, it is literally impossible to do this to the tolerances required if you intend to take guided, timed exposures when photographing either piggyback or through the scope. One soultion to the problem is to purchase the upgrade version tripod with adjustable legs. That takes care of one problem but then you have to purchase either the standard upgrade wedge or the heavy duty wedge. You may think this is enough. Not so ! Next you need to buy the fine tune latitude adjuster. You can check prices at Celestron Dealers and rest assured, you can invest well over $300. What I have done is to make the existing tripod/wedge adjustable by using some materials I had lying around gathering dust and by making minimal purchases . After viewing what I have done, along with the materials I used, you will at least get an idea of what I have tried to accomplish. I have created a numbering system on the scope photos that correspond to a list. After viewing the list and photos I'm sure you can improve on my design. I started out to simply make a simple latitude adjuster and one thing led to another. Had I planned the entire project I'm sure the finished product would have a neater appearance.
Note, All numbers do not appear on every picture. At the end of this page you may want to highlight the method of installation text, copy and save it to a file and then print. This way you may view the images as you read the procedure text.

THE NUMBERING SYSTEM

If you right click on the images you can select zoom in for closeup viewing. Click here to download this feature.
1 - Factory Latitude Adjusters
2 - Azimuth Shelf 3/4 x 11 1/4 x 13"
3 - Wedge Tilt Plate
4 - 1"x4"x1/8" Flat Steel
5 - 5/16" Turnbuckles
6 - 5/16" All Thread Rod
7 - Azimuth Tension Knob
7a- Azimuth Fine Tune Knob
8 - Eyepiece/Accessory Shelf
9 - Aluminum Back Plate For #2
9A- Aluminum tripod top plate
10 - 5/16" Lag Screw Hook
11 - Wood Platform [2x4's & Plywood]
12 - Leveingl Rods [1/2" all thread]
13 - Casters [ one should swivel ]
14 - Latitude Fine Tune Knob
15 - 5/16" All Thread Rod
16 - OTA Counterbalance Weights
17 - Home Made Focuser [not recommended]
18 - Anti Vibration Pads
19 - Old AOL CD's [ For Washers ]
20 - 1/4x20 All Thread Rod
21 - L Bracket [Threaded for 1/4x20 rod]
22 - 1 1/2" x 1 1/2" L Bracket [2 required]
C - - Notice Countersunk Holes

The #14 knob is a round wood dowel
bolted to the #5 Turnbuckle.

Don't forget, you can right click multiple times to zoom in for a closer view. If your Internet Explorer right click menu has no Zoom feature, you can get one with these free tools from Microsoft. #17 is a focusing aid for astrophotography.

Disregard numbers 22 thru 28. My futile attempt at a motorized focuser

Just a different angle to view the azimuth knob and accessory shelf.
Once again disregard the focuser numbers.

In the image above and below I show the rod from the knob 7A connecting to the L bracket #22 directly to the tripod. As an after thought I repositioned the L bracket and added a second one as seen below in the full page sized image of the underside of the shelf board and plate. The two shelf brackets are joined with a screw and double nut which allows them to swivel unobstructed.. This allows a smoother and longer degree of travel in the azimuth adjustment.
This image doesn't show an aluminum plate that I added later to the top of the tripod. It is 1/4x11 1/4x6. Look for it's installation method in the text following all images.

I know, my counterweights look rediculous. I picked up some scrap metal at a machine shop but some pieces were too big so I'm temporarily using what's available. My scope is only set up in my isolated rural driveway so it doesn't have to win any beauty contests.

Above is item #9A It is mounted to the top of the tripod in the position shown using 10/24 round head machine screws. This requires drilling and tapping the plate. The rod shown in the center is 1/4x20 all thread mounted to the tripod itself and passing through the plate. Notice the L bracket. It must be installed before mounting the plate.
Below is the Aluminum Plate #9 mounted to the underside of #2, the wood shelf board. Drill the plate in eight evenly spaced places, countersink the holes and use #8x3/4" flat head wood screws. Be sure the screw heads are sunken below the plate surface. When operational the top plate will slide across the bottom one with a thin layer of lube between.

THIS IS THE FUN PART

Just remember, if you really want to tackle this project, please familiarize yourself with the photos and list of required materials.
I fashioned the azimuth shelf and backed it with the 1/4" thick aluminum plate for economics and because I don't have the required tools to work with 1/2" thick aluminum. Otherwise I would not have used wood.

#1
Remove the three bolts that hold the Optical Tube Assembly (OTA) to the Tilt Plate and lay aside. From the underside of the tripod top, remove the six screws that hold the latitude adjusters to the tripod top. Be careful not to loosen the Allen head adjusting screws on the tilt plate.
#2
Position the wood azimuth shelf #2 over the tripod top as shown in photos. Insert pencil or punch from under the tripod up through the original six holes and mark the shelf. Drill 5/32" holes all the way through. Countersink halfway with a 1/2" paddle bit. This will allow you to reuse the original screws and washers for reattaching the lattitude adjusters.
#3
Add the aluminum plate #9 to the underside of the shelf. Countersink the mounting holes and use #8x3/4" flat head wood screws.
#4
On the tripod top halfway between the siderails drill a 5/16" hole. Insert a piece of 1/4x20 threaded rod and tighten with a lockwasher and nut above and below. The length will be determined by the type azimuth knob you use. I made mine using a 4" holesaw to cut a piece of 5/4 deck lumber. I placed a 1/4x20 insert in the top side. I used two old AOL cd's as washers between the shelf and knob.
#5
Item #4 is the 1"x3"x1/8th" piece of flat steel. It should be bent to an angle equal to your lattitude. It fastens on one end to the center OTA mounting bolt and at the other end to a 5/16" turnbuckle. The opposite end of the turnbuckle attaches to a piece of 5/16" threaded rod and is bent at it's far end to attach to the #2 azimuth shelf. Item #14 is merely a round wood handle for ease of fine tuning the latitude adjusting turnbuckle. When using the slo-mo dec adjuster there is no need to completely tighten the four factory allen head adjusting screws. Leave them just loose enough to allow the up/down movement.
#6
Item #21 is a home made L bracket from 1/8x1" flat steel. Drill a 3/16 mounting hole in the long side and a 7/32 hole in the short side. Tap the 7/32 hole with a 1/4x20 tap. Drill a 3/16 hole in the underside of the aluminum shelf plate #9 and mount the #21 bracket with a #8x3/4 wood screw as shown. Leave slightly loose so the bracket can swivel.
Item # 22 is a standard 1 1/2" x 1 1/2" L bracket. One attaches to the tripod as shown with a 10/24 screw, lockwasher and nut and its' open end needs to be horizontal as it will attach to the L bracket on the end of the 1/4x20 azimuth slo-mo rod. In the future I intend to come up with a better arrangement for this. Use a knob of your choice for the #7A az slo-mo. Mine was made from 5/4" deck lumber cut with a 2"hole saw. Place it and it's rod in the #21 L bracket's threaded side and screw it in untill the knob is about 2" from the shelf and the far end is in a position where the two #22 brackets align. When installing this L bracket I placed two 1/4x20 nuts on the rod and tightened one against the other. This will hold them in position. Place a 1/4" flat washer on next. It then is inserted through the second #22 L bracket. Place a washer on this side and two 1/4x20 nuts are placed on and run up to the bracket. Leave just enough space between the bracket and the nuts on either side to allow the az rod to turn with no slop. Tighten the last two nuts against each other as before. I used a 5/16 bolt 1/2" long to join the two brackets as this size fits snuggly in the factory installed holes of the L brackets. Use washers on each side and a locking type nut. Again, tighten sung but only enough to allow one to move against the other. If you use a compass to set up the tripod for polar alignment, this azimuth adjuster will give you 3 to 4 degrees either side of center for adjustment. Sure beats moving the entire tripod and re shimming for level.
#7
Since the OTA in its' fork mounting extends totally to one side of the tripod there in no balance to this setup. The #7 azimuth tension knob must remain ever so slightly loose to accomodate using the #7a az slo-mo adjuster. So there will be no slop in the dec axis when this is in use I placed 14 pounds of scrap metal on the azimuth shelf board. The scrap I obtained from a machine shop was not enough weight so I have temporarily added the motor you see in the picture.
#8
Item #8 is the accessory shelf, 3/4 x 12 x 17" finnish grade shelf lumber. Form a slight curve to the eyepiece end for a more professional appearance. I evenly spaced five 1 5/16" holes with a paddle bit. To install it drill a 3/8" hole in the tripod top exactly 4 1/2" from the front or south end. Drill a 3/8" hole in the shelf 6 1/2" from the far end. The length of the 5/16" attachment rod will be determined by the method you use for the tripod leveling platform if you so decide to build one. You may install the shelf rod with 5/16 nuts and washers above and below the tripod top. Where the rod extends through the shelf use larger fender washers to help stabilize it. Be sure to hold the shelf up tight against all three tripod legs when tightening it in place so it won't wobble. If you go with the platform the 5/16 rod needs to extend down to a 5/16 turnbuckle. In line with that, place the #10 5/16 screw hook in the platform top. Use a hacksaw to remove enough of the hook to make it more of an L rather than a hook. This will allow easy removal of the tripod from the platform for transport if you so choose. Make the rod long enough to place vibration dampers under the tripod legs. You can purchase the pads for $45 or $50 or make your own as I did. I had worn out running shoes and cut three evenly sized pads from the soles. They seem to have four layers of rubber and sandwiched cushioning material. I have found that an eight second period of image stabilizing reduces to two seconds with these pads. I shaped them on a grinder wheel and they look as if they are factory made.
When tightening the turnbuckle be sure you have the tripod legs fully extended. Tighten a bit then recheck the spread. Do this two or three times to ensure total stability.
#9
Building the platform. This is a true Rube Goldberg contraption. I needed something simple to move the scope from my garage to my setup site on the driveway. Plus I needed a way to level it ONE time. I emphesize ONE because to polar align the standard C8 tripod you have to shim the legs to level it. If you move it even slightly you need to relevel and shim, over and over. Once the platform is leveled, adjusting with the az slo-mo knob eliminates that procedure. The dec slo-mo eliminates the dreaded C8 declination procedure.
I won't give dimensions for the platform. You may have a much better idea. Suffice to say I sandwiched 2x4 lumber between 3/8th inch plywood making sure I had one 2x4 directly under where the #10 lag screw hook attaches. I then added a T arrangement of two 2x4's to extend beyond the pad for attaching the #12 leveling rods. Again I used a 4" hole saw to cut the knobs from 5/4" deck lumber. Cut the three foot piece of 1/2" all thread into three 12" pieces. Use washers on top and bottom and tighten securely to the knobs. At the ends of the "T" drill a 5/8" hole. Countersink around the hole with a wood chisel top and bottom being sure a 1/2" nut fits very snug into it. Place a 1/2" nut above and below, insert the 12" rod into each. As a finishing touch to the knobs I drilled a 1/4" hole near the edge of each and placed a one inch long sleeve over a 10-24 machine screw and attached it with a nut above and below. Works just like cranking a fishing reel. I placed three small rubber wheeled casters on the bottom, and gave it all three coats of black gloss latex enamel to match the Celestron paint.
#10
To sum up.
Clearly what I've done can't come close to factory made devices but I was getting to the point of giving up on observing because of the inherent problems of the standard C8 wedgepod. This system suits me fine and possibly it will spur you to start your own similar project and to make improvements.

In conclusion:
If you have any comments or suggestions please email me here and I will do my best to give you additional info.
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HOW TO MODIFY YOUR CELSTAR C8 WEDGEPOD FOR EASIER POLAR ALIGNMENT

THE NUMBERING SYSTEM

THIS IS THE FUN PART