New Crossbow EQT-200 Equatorial Platform Arrived.
Posted 15 March 2013 - 10:31 AM
For those who aren't familiar with EQ platforms they are placed on the ground, aligned to polar north, and a dobsonian telescope is placed on them. The platform is cocked or reset then turned on. A stepper motor, moving the same speed as the Earth's rotation, then cancels the earth's rotation. This has the effect of keeping a viewed object in the center of the eyepiece without touching the telescope. Without an eq platform the astronomer would have to keep nudging the telescope to follow the object as the Earth rotates. Eq platforms make viewing easier and allow for using higher magnifications since you don't have to manually track an object speeding trough the field of view while zoomed in.
I looked into building a platform as many astronomers do. After all was said and done I felt having a pro do it suited my needs best. Looking around I found three platforms I liked. The Terry O aluminum platform was at the top of my list but also at the top of the price list. Atomic Platforms are still made and are also nice. However, they were a tad undersized for my Lightbridge 16's weight. They are also only sold on Cloudy Nights on a first come first serve basis and come for sale intermittently. The final contender was the Blandin Technical Solutions "Crossbow" eq platform. They had two models of all aluminum platforms priced right.
At the end of November 2012 I ordered a "Crossbow" EQT-200 equatorial platform from Greggs Blandin of Blandin Technical Solutions, 42B Union Way, Vacaville, CA 95687. He can be reached by email at Greggsblandin@earthlink.net. Gregg offers two sized single axis plaforms, an EQT-120 and EQT-200, given their names from their load limits. Greggs makes them in batches so I was on the list for his next batch.
I first contacted Greggs and talked with him extensively about his products. He is an excellent guy to chat with and very knowledgeable. We talked about the genesis of his platforms and their function. He emailed me a flyer and an order form. The order form asked basic information like the weight of your telescope, the diameter of the teflon pads needed, center bolt size, thickness of rocker box, observing latitude, etc. After filling it out and sending Greggs half of the money he went to work.
I selected the Crossbow EQT-200 platform for many reasons. With a load capacity of 200 lbs. it would easily handle my LB16 and also handle any new larger telescope. Greggs said others have placed up to 28" telescopes on these platforms. For $900 it was a steal. A comparable Terry O would go for $2000-$3000. I also like the minimalist all black look of the Crossbow. It matched my telescope well.
Recently Greggs notified me it was completed and he had tested it extensively. It was ready to ship. I sent him the balance and it arrived in the mail this week. The box was well padded on the inside with foam lining. Each part was bubble wrapped extensively and squeezed into the padded box. Greggs had also emailed me assembly instructions. To save on shipping he partially dismantles each platform so there is some assembly required. Everything was perfect after unwrapping. Finish of each piece was impeccable and professional.
Posted 15 March 2013 - 10:35 AM
Posted 15 March 2013 - 10:44 AM
Posted 15 March 2013 - 10:50 AM
At the other end of the lower bearing and drive assembly center support the cap comes off too. This reveals a small circuit board. This board regulates the voltage giving just the right amount of power to the motor. You can use a 9v battery, four AA, or two D cells. Each will be regulated to the correct amount going to the motor. Versatile.
Posted 15 March 2013 - 10:53 AM
Completed lower part.
Posted 15 March 2013 - 11:08 AM
Proper drive friction is essential to platform performance. The ideal amount of drive friction is slightly more friction than the minimum needed to drive the platform through its entire range. Excessive drive friction will make resetting the platform difficult and put stress on the drive gears. The drive friction is increased or decreased by raising or lowering the drive friction lever on the drive side arm. Raising the drive friction lever increases the drive friction by lowering the black drive side bearing. This allows the weight of the telescope to rest on the orange drive wheel and be shared by the black bearing. This gives the orange drive wheel traction to move the telescope without having to bear the entire weight thereby increasing drive effort and wear. Lowering the drive friction lever decreases the drive friction, by raising the black free wheeling drive side bearing shifting weight off of the orange drive wheel completely. To reset the platform, switch the platform electrical switch to the “off” position. Lower the friction lever as shown. While holding the lower assembly in place, push the platform top away from that side until it reaches the stop. Raise the lever as shown, then switch the platform electrical switch to the “on” position.
I was told by Greggs that this is the first batch of platforms with this new friction lever. It really makes resetting a breeze. When the lever is released resetting takes minimal effort.
Posted 15 March 2013 - 11:11 AM
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Posted 15 March 2013 - 11:19 AM
This platform was custom made for my latitude. However, if I change locations the feet can be raised or shimmed to adapt to the new viewing location on the globe. By lifting the north or south end 1/2" it will adapt to one degree of latitude. Very flexible.
Posted 15 March 2013 - 11:24 AM
Posted 15 March 2013 - 11:28 AM
There have been cloudy nights since it came so it still awaits first light. However, setting it up and running it indoors lets me know it works perfectly.
Posted 15 March 2013 - 01:03 PM
Posted 15 March 2013 - 01:13 PM
Posted 15 March 2013 - 02:15 PM
.....perfectly indoors doesn't necessarily equate to perfectly outdoors under the stars in the heat of battle. I bet it will work fine outside, but one never fully knows until real world application.
Posted 15 March 2013 - 03:24 PM
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Posted 16 March 2013 - 04:15 PM
This is a great write up! Thanks.
Posted 16 March 2013 - 05:47 PM
Posted 17 March 2013 - 03:45 AM
I really must stop looking at your posts ... every time I do it ends up costing me money! Excellent write-up - this is something I've been looking into for a while to help with my sketching. I'm looking forward to hearing a review of its performance. In the meantime, I'll start swinging the hammer at the piggy bank!