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Dubliner

New Skywatcher 200p Flexi Dob Auto -problem?

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Hi,

Hope someone can advise on this. It may be backlash issue but to be honest I only have an poor idea of what constitutes backlash.

Brand new scope - just arrived & setup today!

Seems like a great scope but somethng has me worried,

I have very carefully set it up and have it set to my latitude.

I notice when I raise the scope in declination using the up arrow when I let it go the scope more or less stops straight away and the motor stop whirling but when going down using the down arrow if I let it go the scope keeps going down for about 2 secs with the motor slowing before stopping - a huge amount of travel. The amount it over shoots is commensurate with the fast or slow rate.

What is odd too is that when going down if I overshoot my target ( a far away tree!) because the motor keeps running if I then try correct by pressing the up arrow it just keeps going down - like the up arrow is acting like the down arrow!

I must wait for the motor to stop swirling before I can use the up arrow properly.

I have no extra items on the tube just what it came with.

Is this normal behaviour? Is this 'backlash'?

Many thanks.

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There is some backlash on the auto flextubes. To reduce baclash follow the instructions precisely when aligning and setting the altitude. For altitude setting finish the setting to 0 degrees on the up arrow, and finish the altitude setting again on the up arrow. When viewing - If your object is in the East - finish L/R movements on the right arrow and up/down movements on the up arrow. If in the West - finish L/R movements on the on the left arrow and up/down movements on the down arrow.

It can further be reduced by stiffening the base sides a little - and adding a little friction to the turntable. Also counterweights to balance the tube more accurately will also help.

Cheers :)

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Thanks Brantuk for your reply.

I did follow most of those steps as I've been a lurker on this forum for many weeks, however I did not know about the East/West thing so I will follow that next time out.

Lucky me just got a brief break in the clouds (just getting darkish here) and slewed very quickly to the Double Cluster just 10 mins ago - WOW! I have a Nextstar 102SLT up to now. I am just going to love this scope! What a view - breathtaking in this 8".

On slewing when tracking the down arrow behaves itself ( I know the rates are much less when in tracking mode) but I really am frustrated when in normal slewing mode -even Slow Rate. Any key up/left /right moves a reasonable and predictable amount in the 25mm eyepiece - say 5/10 presses to move out of the FOV , however hit the down arrow once and the scope just goes into a slow dive and even if I had a 100mm eyepiece (?!) it would be out of view. Wanted to get away from GOTO as I needed actually learn the sky and hope following your tips and find a workaround for this issue as it might turn me off the effort, For a first night out other than this difficulty it looks like a really great scope and tracks well. Thanks again.

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When it dives on the down arrow it might be due to overbalance at the front. When the motors are switched off - does it go nose down from horizontal?

If so you might need a rear weight to counterbalance it, or a little more grip at the sides.

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Hi ,

Thanks for reply.

No it does not go down by itself when the motor is off. There is nothing only a supplied 25mm eyepiece on it. What I notice is that with the other arrows when I lift my finger off there is a tiny little click when the motors turn off - which is instantaneous. With the down arrow there is no such stop, one hears the motors slowing and I assume it is just friction that brings the OTA to a stop after it has travelled about 10 degree of downward motion (more than intended).

Cloudy tonight , might have a chance to try it out tomorrow, but this behaviour is so pronounced that one only has to look at the OTA/mount to observe it. Regards.

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Hmmm.... check the tube is mounted in the side braces accurately and that the locking knob is firmly done up but not overtight Make sure the rollers move freely without clicking - one of them may be loose. Make sure there's no obstruction between the base and the mount. Everything should glide effortlessly when properly attached and balanced with no discernable clicking.

Cheers :)

Edited by brantuk

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Hi,

Thanks again Brantuk for those tips but I have checked all of those things and they are fine. When I level the OTA it only takes a small tap at the top of the OTA or pressing the down button to to send it into nose dive.

FLO are dealing with it as I've gone as far as 'I' can.

Below are a few videos to try show issue. Last night the sky clear but just powered it off as pressing the down arrow just sent the OTA downwards -either with one big jerk or a slow unstoppable slow decent - even pressing the up button can not stop it when it decides to tip down. Again, I appreciate you took the trouble to help me out.

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No probs Dubliner - I'm sure FLO will sort out the problem - let me know how you get on and how it gets resolved :eek:

All the best!

Just watched the videos - and I agree the behaviour looks bizarre - I'd guess there may be an altitude motor/encoder problem or a handset problem.

Edited by brantuk

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Hi Dubliner,

Did you get your problem fixed? My 300P seems to have developed a similar problem.

Cheers

Tom

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