Hi Guillaume,

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Attached is a photo with the Eagle4S mounted on a homemade plywood bracket that attaches where the wheelbarrow handles normally attach.

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And here is the block diagram of the equipment connections (just realized this does not show my focuser)

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And my power diagram

My Focuser is the Primalucelab focuser and it works great with the FeatherTouch.

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One of the key elements of this was the Pegasus USB3 hub that has the ability to use all previous versions of USB at the same time.

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ServoCAT uses USB 2.0 while my Mallincam video camera uses USB 3.0.? I have not found any other USB hub that supports all USB protocols at the same time except for the Pegasus hub.

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I wrote some Visual Basic software to parse all my data for entry into my MS Access database.

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Good luck with your Telescope system.

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Richard Miller

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Woes concerning the UC series are not uncommon.? Here are mine.? In 2017 I bought a nearly new Obsession 18UC from a fellow using?AstroMart.??He had ordered the scope from Obsession and while it was being built contracted a debilitating medical condition that forced him to sell his scope after it was delivered.??He was never able to even look through the scope as his wife was unable to set it up for him.??I managed to acquire the scope at quite a discount.??It was loaded but did not have?ServoCat?installed.??I purchased a?ServoCat?Jr. system from Gary at?StellarCAT?who provided hours of technical assistance in getting a working installation.??Thus began my love, hate-hate relationship with my Obsession 18UC.??The optics were superb, however the mechanical implementation of those optics in the UC platform was flawed.??The design criteria that the scope must fit inside the 26.5” cube airline box was probably the root of the?telescopes?stability issues.??As to meet?this criteria, many shortcuts had to be taken.??All of which contributed to the inability of the scope to hold collimation?during the course of?an evening’s viewing.??The other significant issue with the scope is the amount of flex in the scope when being driven by the?ServoCAT?system.??If you were looking at an object under high power and you needed to “tweak” its position in altitude just a smidgeon to recenter it in the eyepiece’s FOV you were in for a very frustrating experience.??Normally you would select the lowest guide speed on the?ServoCAT?hand pad and poke the up/down motor control buttons as necessary to recenter.??With my 18UC if the last direction the scope had travelled was the same direction you needed to move to recenter, you might get lucky and get it recentered without much fuss.??However, if the direction was opposite of the scopes last altitude movement the scope’s Virtual Mirror Box (VMB) would shift so significantly in the Rocker Box (RB) that the object of interest would be thrown about a half of a degree out of the field of view, then the dance to recenter trying to overcome the VMB and RB slop would ensue.??The slop between the VMB and RB caused me hours and hours of grief as well as many $$$ trying to correct.??I spent a very significant amount of time on the phone with Dave K. of Obsession and Gary with?StellarCAT?trying to resolve the issue.??Dave K. finally gave up and simply told me that the scope met his design criteria.??After three years of fighting this scope, I basically packed it away when we moved to Colorado.??I ended up finding another Obsession Classic scope (20” F5) on AstroMartand have been happy with it.??It is not an ideal telescope for public outreach as the climb to the eyepiece when near zenith was a strong concern.??So, I used the Obsession Classic 20” for personal viewing only.??In 2022 I found that Astro System, the maker of the?Telekit?wood kits for Dobsonian telescopes, would?actually build?the wood enclosure of the?Telekit?for you. I contacted Randy at Astro Systems and?made arrangementswith him to build a new enclosure for my 18”.??I removed all of the telescope’s guts (optics, electronics, focuser, motors, DSC, and finders) and took everything to Astro Systems in La Salle Colorado, about a four-five hour?trip from my rural home in Westcliffe in May of this year.??Randy built my new enclosure, reconfigured (with the help of Gary at?StellarCA) my?ServoCAT?Jr. system to work with the?Telekit.??I picked the scope up last week after about 2 1/2 months and brought the scope home.??After some initial configuration setting issues with the Nexus DSC and the?ServoCAT?(different size bearings and ground board changed the gear ratios) I took the scope outside in the light of a 89% full moon last night and did a single alignment with two stars and then told the new scope to go the binary pair WZ CAS and lo and behold the scope zipped on over and placed the pair within the FOV of my 10mm Pentax XW eyepiece.??Next was Albireo, it was a little toward the edge of the?FOV?so I selected the lowest guide speed on the?ServoCAT?and was able to center Albireo perfectly.??I purposely moved it all over the FOV alternating between the up/down motor controls and the amount of slop was not even noticeable.??I can not express my gratitude with Randy of Astro Systems and especially with Gary at?StellarCAT?whose patience and perseverance helped me achieve the full potential of the original guts of my former Obsession 18UC.??Now I proudly proclaim that I have an 18TK that works like a dream.??

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I had serious conversations with Webster Telescopes, DOC Telescopes in Italy, New Moon Telescopes, and Teeter Telescopes Before I chose Astro Systems for my rehost project.??So if you are experiencing frustration with your Obsession UC telescope, I whole heartedly recommend rehosting your telescope’s “guts” into another host, and I will attest that Astro Systems was the best choice for me, and probably for you as well.

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Customer complaints for products and services should not be ignored. ?I doubt that a group of enthusiasts and satisfied customers will be persuaded to join your cause if they have not been denied the customer service, or warranty repair or a refund from the supplier of the defective product.

I hope your complaint is addressed and wish you a speedy resolution. ?

Regards,

Richard

The problem with the Obsession 18” UC is the trade-offs to make it super portable and capable of being put into the white plastic airline shipping box.?

Folding bearing arms

Thin upper ring

Virtual Mirror Box (VMB)

Rocker Box (RB)

Six Pole Set

All of these parts are made out of plywood (except the poles).

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I have owned six big dobs 14” or larger.? Two Obsessions (a 20” Classic and an 18” UC), a Night Sky 16”, a 20” Sky Watcher Compact Scope, an Orion Goto 14”, and my Telekit 18”

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The very best mechanics of the group, the 14” Orion Goto – hands down the most reliable, easy to setup, and most accurate GoTo operations.? But it was impossible to move after its setup unless you build a “dolly” for it.? The hardest to setup was the Sky Watcher 20”, and this scope executed the poorest implementation of a known working GoTo system.? The Obsession 20” is a beast that takes a bit to setup but is rock-solid with a Servo-Cat and the Nexus DSC GoTo system workings very well, and is very stable and holds collimation all night (across many nights as long as you don’t dismantle it).?

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The 18” UC was purchased after the 20” Sky Watcher fiasco (Sky Watcher fully reimbursed my purchase price and paid for return shipping after I documented all of its shortcomings (two months later Sky Watcher stopped producing the GoTo version of the scope).? The 18” UC came with nearly every option available with the exception of ServoCat.? Which I bought from a fellow on AstroMart who never even set he scope up after contracting a severe medical condition.? I contacted Gary at StellarCAT who sold me a ServoCAT Jr. system and provided EXTENSIVE customer service so that I could have a good installation.? Initially the 18” UC employed an Argo Navis DSC system from Wild Card. ??The first issue with the telescope was that it would lose collimation after a few movements from one side of the sky to the other.? Too much flexing in the poles and upper cage assembly.? The second major issue was the slop in the VMB.? Under ServoCAT it would slew accurately and place an object within the FOV of a 17mm eyepiece.? If you wanted to recenter the object is where the slop issue rears its head.? If the last altitude direction of the scope was up and you needed to poke the ServoCAT motor control buttons in the up direction (same direction as the last movement) you could reasonably expect to get the object back to center.? If you had to move the scope in the opposite direct of its last altitude motion, you would press and hold the motor control button for about a full second before anything happened, then the cable would start to move the VMB, the first movement would be a SHIFT of about two to three degrees (eyepiece FOV) as the VMB shifted in the RB as the torque from the altitude motor was applied.? Dave K and Gary bot suggested a set of additional Teflon pads attached to the RB with screws to help keep the VMB from shifting excessively (these are in addition to the Teflon supports Obsession nailed in, but easily pushed out by the VMB. ?Dave K. sent me a set of steel stiffener bars that attached across the tops of the bearings to provide a little more stiffness (this was supposed to eliminate the collimation issue and help with the VMB shift) these would help the scope maintain collimation for a dozen or so more slews across the sky but did nothing for the VMB shift.? Gary from StellarCAT gave me many, many suggestions on trying to minimize the VMB shift.? These were pretty much all in vain.? By this time Dave K. had given up and stopped answering emails, and simply told me that the scope met his design criteria.? Gary and I ran out of things to try, so sadly the scope with some of the best optics I have had, was sidelined from its purpose of providing public outreach and I fell back to my trusty 12” Orion GoTo.

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This spring I contracted with Astro Systems to build a Telekit that would host all of my 18” UC “guts”. ?After three months, Randy at Astro System informed me the new scope was ready for pickup.? Once home and the proper bearing ratio configuration data was entered into the ServoCat the scope is fully operational and my previous 18” optics are now once again in use.? No noticeable mirror box shifting is seen in the eyepiece FOV while changing altitude direction, and it holds collimation exceptionally well.

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Overall I spent about one and a half times as much money as a new 18” UC with ServoCAT directly from Dave K. would have cost? If there would have been a few HONEST reviews of the 18” UC up on the forums, I would NOT have bought the UC platform, I would have bought a 18” Classic with ServoCAT.? That sure would have saved me a lot of time, effort, and tons of grief.

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I am a “Fan Boy” of the Obsession Classic line, I have seen many at star parties and looked through most, as well as competitors scopes. And the Obsession Classic is truly a very good scope.? The excursion of Obsession to the UC line was a mistake in my opinion.? The best UC style scope if you have the $$$ is a DOC telescope (Italian made) with the New Moon hybrid scopes a close second.? Webster still makes a premium classic style scope as well, but they are a bit expensive.

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Dave designs and manufactures his own scopes.? He has successfully run his own US-based company for decades while competing in a global market place that is dominated by low-cost, off-shore manufacturers who sometimes copy US designs and sell them back to us at lower cost.? How many people can do what Dave has done?? Dave is a great American.

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Go read any forum about any piece of gear (astro-related or otherwise) and there will always be complaints about the product being a complete piece of garbage.? Some of these posts are legit, some are placed by competitors, some by internet trolls, and some are posted by complete nut jobs.? But even the legit complaints are usually outliers.? All sane and saavy buyers will read a couple of “one star” complaints and recognize them for what they are.

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None of the dozen or so telescopes that I have purchased in the past 50 years has worked flawlessly right out of the box, and as the scopes have gotten more complex and more expensive, the problems have gotten worse.? Back in the day (at least in my experience), most problems were mechanical in nature, but the worst problems tended to be intractible (bad optics for example).? Not much the average buyer (me) could do about a bad mirror or lens, unless you could get the vendor or mfg to agree that it was bad.? These days, the optics have gotten much better, but now the problems have to do with electronics, cables, connectors, motors, power, etc.? Although I will point out that I bought a highly regarded and popular 5” refractor from a respectable vendor about 8 years ago that was delivered with several screws rattling around loose in the box - having worked themselves loose during shipping across the Pacific.? So we’re still having mechanical issues too.

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There was a time when I too felt agrieved by this state of affairs, but it has occurred to me that if these products were all flawless, I probabaly would not be able to afford any of them, the market for these products would be much smaller (catering only to wealthy customers), and we wouldn’t be having this conversation.

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Of all the scopes that I’ve purchased over the years, the OBSESSION UC18, while not perfect, is hands down THE BEST TELESCOPE that I have ever owned. ?Thank you, Dave.

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Bob