sky-watcher 200pds major problem

[tech_01]

Hi all newbie here, i  purchased a brand new sky-watcher 200pds  with eq5 mount and syn-scan goto system and a lot of other extras .  the problem started when  i used the goto  the DEC motor started making a ticking sound, anyways i pulled it apart and found a broken tooth on the drive motor sprocket just great, i rang the supplier and he said he will send a courier to pick it up and they will send a new DEC motor  but due to my work  and the hrs as a shift worker  he  still hasn't organized a time to pick it up, dont worry it gets worse?.

Back to when i first used the scope mars was rising in the east it was so bright  i pointed my scope and found mars,i went to focus out but it kept going blurry focused in and all i got was a bright round circle , collimation was spot on well thats what i thought so i packed up the scope its been covered up in the garage ever since. two days ago i went out to the garage as i wanted to find out what was wrong with it  this is what i found.  the telescope tube has a dent  all the way from the spider to the the main mirror  the tube rings were done up finger tight  i also found a small dent  on the tube just to the right  of the focuser  i bought a baader laser collimator mark iii i checked it for collimation it was all good.

 

So in the scope it went  collimation was off  after a minute or two  i got it bang on well until i focused out  it threw the laser right out of collimation, ive tried adjusting the the focul tube 2 hex screws underneath the focal tube and the laser goes back to being centered until i focus out, ive tried to collimate the scope with focus right out when i focus in once again it throws out  collimation ive also noticed when i screw the front  tube ring  in and out it moves the laser out of collimation,  ive  contacted the supplier in Sydney about problems haven't heard for a week so i emailed them again and now waiting till Monday for answers the pic below shows dent any help would be great.?

 

[Ricochet]

The first thing that I would do would be to remove any extension tubes and reducers from the focuser, and then reinsert them, making sure that they are square. Any tilt in one of those or between the eyepiece clamp and your laser could produce this issue. Once you have done that check if the issue persists. If it does then it suggests either:

• There is slop in the focuser or it is not running true, which you can probably fettle out (hopefully someone with the same focuser can advise).
• The tube itself is flexing simply under the moment of the focuser being slightly further out from the tube. If you can tell that this is the issue I think you would be entitled to a replacement as I do not think this is normal.

With regards to the dents I doubt that any of these tubes have perfectly circular cross sections, so if the deviation is consistent the entire length of the tube that might be considered "normal" although yours would appear to be an extreme example. The fact that tightening the tube rings can flex the tube doesn't sound right. With an eq-mounted reflector you would be loosening and tightening the rings several times in a session if you are using it visually and you can't stop to recollimate each time. If there is a local astronomy group I suggest you contact them and see if there is anyone who would be prepared to have a look at it and give a second opinion.

[david_taurus83]

How long have you had it for? I'd be returning the lot for refund and find a different supplier. The tube shouldn't be dented if it's new and you shouldn't be expected to remove the motor covers and housing to discover broken teeth!

[happy-kat]

Also check the laser collimator is itself collimated.

[tech_01]

thanks everyone for the feedback?, i purchased the scope in November last year i have also checked the laser for collimation by rotating it in a jig dot stayed centered, will wait for answer tomorrow from supplier ?

[Stub Mandrel]

Watch the laser spot on the main mirror as you rack the focuser in and out. If the spot moves along a short line the focuser is not at right angles to the tube - the spot should remain stationary.

[tech_01]

hi, did that the spot tracks to the outside of circle on main mirror goes totally out of collimation it doesn't matter what i try , also took my focuser apart all the screws nearly fell out everything was loose the really bad news is when i rotated the scope in the tube rings the tube is egg shaped in all directions will be demanding a refund or a new scope?.

[John]

I don't think the shape of the tube is the problem. I have an Orion Optics 12 inch and the tube on that is not at all circular. It has a clear flat spot where the seam of the tube is and that runs the length of the tube. This does not affect the collimation or the performance of the scope though.

Look at this photo of an Orion Optics tube and you can see what I mean:

 

[tech_01]

hi john nice scope, i see what you mean but on  my skywatcher the join in the tube is fine  the flat spot is not near  the join also  when i rotated the scope in the tube rings the tube has flat spots all over it,  they are not small either ? i shone a small torch around the outside of the focuser  there is  about a 4 ml gap between scope and focuser . ive collimated scope again  same problem 1/4 turn out on focuser the dot goes out of the center  circle of main mirror , it doesn't matter what screws i tweak nothing changes, thanx to all for your input?.

[tech_01]

just an update on my skywatcher 200pds , the supplier wanted me to tear it down and send parts in for testing? yeh not happening , i told him its still under warranty  and there needs to be a better solution , looks like new scope coming my way....?