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New Crossbow EQT-200 Equatorial Platform Arrived.

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#26 Project Galileo

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Posted 17 March 2013 - 08:21 PM

I am glad you all enjoyed the posts.

Today I fine tuned my new rocker box to work with this platform. Stock the LB uses a lazy Susan bearing. This mod involved adding an Ebony Star bearing and increasing the teflon pad size to accommodate my heavier telescope. The width of the bearing is 1.5 inches. That means there will be 9 square inches of surface area for the teflon pads. This is more in line with a 15 lbs per square inch of telescope weight recommended. It works great now.

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#27 Project Galileo

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Posted 17 March 2013 - 08:23 PM

I do believe this baby is star worthy. Tonight will be windy but doable. I am excited.

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#28 Project Galileo

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Posted 18 March 2013 - 11:16 AM

First light with the Crossbow eq platform was a charm. Last night viewing conditions weren't excellent but they were doable. It took moments to set up. First I laid the eq platform down and eyeballed north, leveled the feet, and set the telescope up on top of it. Then after a quick collimation routine I spun the telescope around, turned on the fan, reset the platform, and put in an Orion 20mm illuminated centering eyepiece then focused in Polaris. A flip of the platform's on switch brought the crossbow to life. Now I went inside and left the telescope to cool and track for a bit. It took me about 10 minutes to get it set up to this point.

After 15 minutes I went back out and checked Polaris. It had moved ever so slightly from the cross hairs. I almost nailed alignment by eyeballing it. Pretty cool. I have to say the long axis of the north/south part of the platform gave me a nice long part to eyeball while setting it up. Nice. I bent down and nudged the south end of the platform to make the correct drift alignment. I was glad there was the part that sticks out on the south end. It gave me a great point to push and lever the platform while it was set up like this. Polaris was re-checked for center then I went back inside.

After 10 more minutes I went back out and checked Polaris. No appreciable shift. I was excited now. The platform had gone through almost half of it's radius by now so I reset it. The Great Orion Nebula/M42 was hanging above just asking to be looked at. I spun the telescope around, put in a 13mm Nagler T6 and focused on the target. The nebulosity just hung there in the center, not drifting, not moving, just being. I watched for a few minutes marveling and getting my head around the new experience. My big dob was tracking effortlessly.

Ultimately I wanted to see how close it tracked so I put the Orion illuminated cross hair ep back in and moved down centering Rigel. Again, I just let it drift. After 5 minutes it still was dead on. I figured this was a good time to take the dog for a walk and earn brownie points with the wife. Coming back 30 minutes later Rigel had no appreciable shift. I was so happy.

I spent the night hopping here and there for another hour or so. I was able to go back to M42 and put a 2x Barlow on the 13mm T6. It was so sweet to not have to nudge and track the target with it zoomed in. At one point I tried to use a 3.5mm T6 but seeing conditions prohibited clarity. I can say that while switching between the 13mm to the 3.5mm eps I could tell the target remained centered albeit unclear for good viewing.

Stability was outstanding. The Crossbow eq platform is more stable than the stock ground board and lazy Susan set up. The radius of the telflon pads on the new eq platform is wider than the radius of the lazy Susan bearing. This has the effect of giving more stability and less rebound time after moving the telescope. The actual platform is rock solid. It takes a significant amount of pushing the telescope in ways it isn't designed to wiggle it at all. In normal viewing the platform doesn't wobble a bit. The platform also tracked through over 60 minutes before needing to be reset. There were no problems at all through all ranges of the tracking radius. It never slipped, stalled, or otherwise stopped tracking accurately the whole night.

Before breaking down I marked the position of the three feet on the ground to speed up set up next time. By not having to drift align I can be viewing much faster now.

I would give the Crossbow EQT-200 a solid "A" grade.

#29 G Blandin

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Posted 18 March 2013 - 12:21 PM

Thanks for letting us know how it worked. Just a tip for faster alignment: you can move the lever up into the reset position and bring it to the beginning of tracking travel. Center on Polaris and just push it through the tracking range manually. That way you don't have to wait. If Polaris drifts: UP- scope too far left, DOWN-scope too far right, RIGHT-Scope pointing too high (shim south end), LEFT- Scope is pointing too low (shim north end).

#30 Project Galileo

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Posted 18 March 2013 - 12:47 PM

Gregg, I thought about tracking manually like that. I had the extra time and other things to do so waiting was not a problem last night. I know when I take it to a dark site setting up manually like you suggested will help. Thank you for making me a wonderful tracking platform.

#31 G Blandin

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Posted 18 March 2013 - 06:17 PM

The scope moves really easily with the reset lever up so what I do is just put some gentle pressure with my foot on the east arm until you feel the stop. Then center Polaris, walk around to the other side and do the same thing which moves the platform through the tracking cycle. Then check to see if it moved.

#32 GWING

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Posted 29 March 2013 - 05:05 PM

Great report! Thanks for sharing it. Greg W

#33 CarsRfun2

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Posted 30 April 2013 - 04:19 AM

Hello,
I have a question. How do you transport the scope? My 18 inch Obsession is heavy and requires wheelbarrow handles and wheels to move.

Clear skies,
Keith

#34 Alvin Huey

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Posted 30 April 2013 - 12:48 PM

My 22" is heaver than an 18" Obsession. I disassemble the scope and carry the three main parts one at a time.

Normally, I put the platform where I want it. Then grab the rocker box, place it on the platform, next grab the mirror box (in your case, you may need two people to carry it from your vehicle) and place it on the rocker box. Assemble trusses, etc.

Note: The round ground board is removed from the rocker box as the platform replaces it.

#35 G Blandin

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Posted 05 June 2013 - 10:37 PM

I pretty much use the same method as Alvin. I am rebuilding my 25" with a low-profile rocker which I plan to leave mounted on the platform when transporting it. I'll post some pics when it's done.






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