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ServoCat / Argo Navis questions

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#1 djeber2

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Posted 09 December 2012 - 10:12 PM

I am considering purchasing a scope with ServoCat and Argo Navis installed. I am not too familiar with these as none of my current scopes have goto or tracking. My questions are:

How difficult or tricky is it to disassemble for transport in my car and reassemble at my dark site a scope with this extra goto hardware attached?

If I decided to purchase the scope but did not want to keep the computers how difficult would it be to remove all of the ServoCat and Argo Navis hardware from the telescope? What would be the typical value of these items if resold in the classifieds used market?

Thanks for any guidance you can offer.

#2 Bob S.

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Posted 09 December 2012 - 10:28 PM

Don, What kind of scope are we talking about? Size/manufacturer?

#3 Cotts

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Posted 09 December 2012 - 10:35 PM

I have servo cat on a 16" Dob. For transport the mirror box and the rocker box/base are most conveniently left as one unit. Depending on the size of the Dob you get and the size of your vehicle this situation will range from trivial to deal-breaker.

You can undo the Altitude motor wire which wraps around a friction wheel in order to separate the Mirror box and the Rocker box if you need to but it is a persnickety job to hook it back up at your observing site, possibly in the dark...

I would bet that 99% of Servo-Cat Dobs are transported without taking t apart like that.

Dave

#4 djeber2

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Posted 09 December 2012 - 10:43 PM

Dave thanks for the information. Bob I am looking at a 15" truss dob.

#5 ausastronomer

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Posted 09 December 2012 - 10:48 PM

It depends on the basic telescope design. The Obsession style scopes (and many others) are designed to be transported with the mirror box and rocker box left together. In this situation the servocat and argo navis causes no tranportation issues whatsoever.

If it was a scope that is designed to have the mirror box and rocker box separated for transport things get a little more difficult and the difficulty depends on who did the install and whether they have installed it with the intention of making it easy to disconnect, with strategically placed disconnect plugs on all the cables. If they aren't installed already it isn't difficult for handyman with with some wiring knowledge to install some disconnect plugs on the cables. I did all my own disconnects on the 18" Obsession. They were already installed on the 14" SDM.

On an Obsession style scope using a catstalk with connectors on all the cables it's a 5 minute job to disconnect the catstalk and cables, disconnect the RJ8 altitude encoder cable and to disconnect the stainless steel wire altitude drive cable. It takes about the same time to reconnect it all.

Having had the luxury of Argo Navis / Servocat for over 9 years, I will never own a scope, over 12" aperture which does not have these fitted. Removing and or selling the argo/servocat is an option that wouldn't even enter my head.

Which scope/design are you looking at?

Cheers

#6 ausastronomer

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Posted 09 December 2012 - 10:54 PM

Bob I am looking at a 15" truss dob.


Which design, who built it? The scope design and construct is the critical thing here, moreso than the aperture.

Cheers,

#7 Bob S.

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Posted 10 December 2012 - 06:53 AM

Bob I am looking at a 15" truss dob.


Which design, who built it? The scope design and construct is the critical thing here, moreso than the aperture.

Cheers,


I am in total agreement with all of the posts. Who designed and added the ServoCat has a lot to do with ease of use and ability to seperate components. GOTO is less important than tracking which effectively increases your aperture by about 1.5-2" because you do not have to bump the scope at higher powers. It also has the advantage of keeping targets in the sweet spot of the parabolic mirror which is very important to image quality. Like others, I do not care for Newtonians over 12" that do not have tracking. ServoCats made by Gary Myers are some of the best tracking systems available and Myers provides great support to the equipment and is constantly upgrading the system to keep it fresh. Bob

#8 Cotts

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Posted 10 December 2012 - 07:17 AM

PM sent

#9 George N

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Posted 10 December 2012 - 08:40 PM

I don’t own a scope with this combo, but I have observed with a number of them belonging to friends with scopes ranging in size from 18 to 32 inches. They work wonderfully, and all the owners said that they love them, would never go back, etc. For me, tracking is almost mandatory on any scope larger than about 25 inches, and even then it would be very handy to have.

Problems:

From what I’ve seen, you need to be prepared for some fiddling from time-to-time to keep ‘um working. Getting grass or weeds caught in the az drive is both easy and damaging. Trapped weeds can wear a spot in the ground board meaning no tracking until it is replaced or repaired. You can always tell the SC guys: they have the fancy ground cover systems and maybe even a weedwacker or clippers!

You have to be more careful with not getting water in the works.

The powered ground board can get a dirty pickup track, poor spring connection, etc. You will have to disassemble and clean it to get it working. Wires and connectors can get messed up.

It’s another thing to learn how to use. (Watched a guy with a brand new Obsession 25 observe for 4 nights without turning it on ‘cuz he didn’t want to try until after he practiced at home on a ‘moon’ night).

You will have to provide power in the field: battery and cable.

The reason I don’t have one (yet): It makes the scope a little wider, and I can just barely fit my 20 thru the house door now. As soon as I replace the sliding glass door with “bat wings” I’ll probably get one (or maybe a larger Dob with one).

#10 Bill Weir

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Posted 11 December 2012 - 01:44 AM

When I ordered my 20" scope I didn't even think about not getting the GOTO/tracking. It was for the tracking way over the GOTO. In fact I barely use the GOTO I just disengage the clutches find the area I'm looking for then re-engage the clutches. With the scope tracking I'm able to really squeeze out those challenge objects. On the other hand it is wicked cool to watch a large dob slew from one side of the sky to the other and land on target.

My scope has Sky Tracker/Sky Commander but essentially it's the same difficulty factor of setup tear down as Servocat/Argo Navis. It adds maybe 5 minutes at the most.

Bill

#11 mtb54703

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Posted 11 December 2012 - 01:44 PM

I built an 18" 3+ years ago and just had digital DSCs. I used it for a year doing a lot of outreach stuff and thought the digital DSCs were great. Then I added the ServoCAT - talk about the best thing since sliced bread!

I don't separate my mirror box and rocker box for transport - so no need to mess with the altitude cable.

#12 Víctor Martínez

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Posted 11 December 2012 - 04:07 PM

I'm waiting to receive a ServoCAT Jr system the next month. To transport the telescope to dark skies, I have to separate the mirror box and the rocker box. I've been studying the ServoCAT installation (I will install it), and I don´t see complicated mount the system, included the altitude cable.
http://www.youtube.c...h?v=5QmTeWCRxIw

#13 ausastronomer

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Posted 11 December 2012 - 05:42 PM

Victor,

It isn't difficult. The only thing you need to keep in mind is that you are going to need to remove the altitude encoder and its arm and the altitude encoder cable. Some scopes are wired internally which means you need to have cable disconnects strategically placed to facilitate easy disconnection of the altitude encoder cable. If you also run the powered ground board and then run power internally to the top end of your scope this power cable needs to be disconnected also. A disconnect plug mounted on the side of the fan board makes this a simple job also.

Internally running all the cables gives you a far better and neater finished product and one you're much less likely to hang any cables up with. However, if you wish to separate the mirror box and rocker box, you need to keep in mind where you need to install disconnect plugs to facilitate easy separation of the mirror box and rocker box.

Cheers,

#14 Víctor Martínez

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Posted 12 December 2012 - 03:47 AM

Thanks, I had already taken into account the aspects your comets

#15 tezster

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Posted 12 December 2012 - 08:38 AM

I've always been curious as to how the servocat system deals with a dob's altitude balance i.e. does the use of the servocat eliminate this problem completely?

I imagine this would be an issue when the clutches are disengaged and the scope needs to be moved manually?

#16 mtb54703

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Posted 12 December 2012 - 09:16 AM

I've always been curious as to how the servocat system deals with a dob's altitude balance i.e. does the use of the servocat eliminate this problem completely?

I imagine this would be an issue when the clutches are disengaged and the scope needs to be moved manually?


In my experience you can get away with being a bit more off on the balance.

Prior to adding the SC, my scope was nicely balanced with a 31mm Nagler in the focuser - the scope was designed with a fully loaded UTA in mind. Moving to lighter EPs I could tell there was less resistance when pushing up, and more when pushing down - I managed to have enough friction that nothing moved on its own though. With a really lightweight EP I would slap a little extra weight on the UTA.

With the SC installed I don't even bother. Gotos are just as accurate regardless of which EP in the focuser.






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