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badgers

Skywatcher Explorer Newtonian Owners - Need Help

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Can Anyone tell me whether their skywatcher newt came with 4 mounting holes for the focuser or with 5 like mine below ?

As you can see there are two holes on the bottom left and not one.

med_gallery_19171_1868_548293.jpg

Ever since I've had my Skywatcher 150P, I've had issues with getting it collimated nicely.

In particular I've had to rack the focuser way off square to get a nice circular secondary mirror.

See:

The key issue is that the focuser seems to have been placed too far towards the front of the tube.

It looks very much to me like they initially messed up the first hole they drilled, then drilled 4 more holes slightly offset to correct the mistake.

This would explain my inability to get the thing to present a circular secondary without having to skew my focuser.

I know it's a long-shot, but if anyone has the measurements from the front of their tube to the focuser mount, or to one of these holes (on a 150P), I'd love to check my measurements, as I reckon my focuser is about 5-6mm too close to the front of my tube and would love confirmation.

Finally, I've no idea how to resolve this...... Should I go back to the supplier (FLO) ? Or work out a way to move the focuser ?

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If I recall correctly, the vanes that hold the secondary are offset down the central axis of the tube. If you take them off and mount them on the opposite side of the holder, the secondary holder is moved up the tube which will give you some extra room for adjustment. You can compensate by moving the primary a little further up it's adjustment range, if you have trouble with focuser travel as a result.

Russell

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If FLO supplied it and there has been no work done on it since they supplied it then it's definitely worth contacting them I reckon. They are the sort of folks who like to help if they can :smiley:

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Hi Anton.

This is a very good point. It would be extremely helpful to anyone with a 150p to find a solution to this issue. I'm afraid I have the 130 or 200 so cant give measurements but have had collimation troubles of similar but not exactly the same problem.I would suggest talking to the supplier before making any adjustments to be safe.

Well spotted.

Aenima

EDIT: I also know someone with a 150p that had a lot of issues with the focusser, to the point of trying to change it.

Edited by Aenima

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I've already tried everything I can do with the spider vanes. No matter what orientation I try, I still can't get the focuser to centre over it without having it way off square.

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I've had it 7 months and have flocked it etc. I will definitely ask FLO what they recommend though.

It's my first scope, so I'd absolutely no idea about collimation until recently when I've become much more details focused for imaging.

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If I recall correctly, the vanes that hold the secondary are offset down the central axis of the tube. If you take them off and mount them on the opposite side of the holder, the secondary holder is moved up the tube which will give you some extra room for adjustment. You can compensate by moving the primary a little further up it's adjustment range, if you have trouble with focuser travel as a result.

Russell

Hang on Russell,

You mean remove the secondary from its base, and then rotate the base to the opposite orientation ?

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My 200 PDS has only 4 holes, talk with FLO they'll help you get it sorted.

Edited by nightvision

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PROBLEM SOLVED

Russell you are a life saver!

Taking the Secondary off its base and flipping the base and vanes the other way around has brought the secondary back up the tube about 5mm and I can already see that I will be able to centre it perfectly now.

The only difference is that my spider vanes are presenting a slanted surface out of the tube instead of being flat as they were before.

Russell, If you are in Kelling let me know, I owe you Beer, Wine or Jaffa Cakes (your choice).

I love these forums!

Anton

Edited by badgers
  • Like 1

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Awesome! I know someone about to buy the SW 150p and worried a little, but now even if he had this problem there is now a solution. I also love this forum!

Regards

Aenima

  • Like 1

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It's a great scope, but that has been bothering me for a long time.....

I really didn't want to have to go down a replacement or DIY hole drilling route.

I think someone mentioned rotating the vanes before, but I somehow assumed they meant rotating them around in the tube on their central axis, rather than flipping the whole assembly back to front.

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Just in case anyone has a similar issue. This is what the secondary assembly looks like with reversed vanes:

post-19171-0-57010300-1341959466_thumb.j

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I'm quite surprised it has five holes. I'd have thought they'd get drilled by machine when the ota was still a flat sheet. Perhaps "men with drills" are cheap in China.

James

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Yes, I vaguely remembering wondering about it when I flocked the scope.

I'd kind of forgotten about the extra hole as it's been hiding under the flock, mocking me ever since.

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I have just checked my 150P and it definitely has only 4 holes for mounting the focuser. Collimation has always been good with my scope. A quick tweak with a Cheshire is all it needs occasionally.

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Thanks for checking Rik,

Fingers crossed that my scope will collimate better now.

I also now have quite an aerodynamic look with my backwards spider vanes :)

Edited by badgers

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I'm all recollimated now and ready to go.

My focuser is almost perfectly square, and I've got a nice round secondary.

Laser and Cheshire both looking good and I can tell it will now hold collimation on the secondary much better than before.

Thanks again guys

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Glad to be of service. :)

I only figured it out when faced with a similar problem on my 300p, although in the end, that turned out not to be the problem...

I didn't bother turning them back round, as there was plenty of adjustment in the screws to take up the slack in the extra 2-3mm of range it provided.

Russell

Sent from my iPad using Tapatalk HD

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Hi, I have exactly the same problem with my dob 150p, i cannot get it to collimate well as the focuser isnt square for some reason. ive tried ajusting the spider veins etc. but the secondary and is very tilted because the focuser is pointing to far down and it is annoying me alot because I am going to be selling the scope in a few months time and I want it to be good for the next person to use.

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Hmm.

Does everyone have a trouble with collimating their SW newt/dob's?

If so, maybe start a thread anew to deal with the issue? Many people have these scopes and could be affected by this problem, might help them get together to solve it.

Regards

Aenima

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Sounds like a good plan Aenima.

Also, I got the best ever collimation results with my adjusted setup the other night.

Getting 1.2" and 1.5" on CCD inspector collimation analysis over 5 frames.

Defocused Star test looked perfect.

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Nice1 Badgers,

I'm not familiar with the ccd inspecter test, I'm guessing you take a picture of something? Longshot, there. So if its totally wrong my bad. If its not a nightmare to explain maybe give me an idea as my collimation is very rough, using a cheshire but still not getting it perfect.

Glad your secondary issue is now gone, you must feel like its a new scope.

Regards

Aenima

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I´´m actually in the process of buying a OTA SW-150P or 150PL, a tad longer. This thread makes me a bit worried. One of my current problems with my celestron 130eq is collimation and a poor focuser that "wiggles". Want to get far away from those problems. =D So, is this a common thing with SW scopes or just a sunday ex?

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I have heard one or two stories of 150p focuser problems, but i have the 200p which to me looks and feels like a new improved design - maybe by now tthey did it for the newer 150p's?

Sorry cant help further, you could possibly find a recent buyer to see if the focuser is a better design?

Good luck,

Regards

Aenima

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I have heard one or two stories of 150p focuser problems, but i have the 200p which to me looks and feels like a new improved design - maybe by now tthey did it for the newer 150p's?

Sorry cant help further, you could possibly find a recent buyer to see if the focuser is a better design?

Good luck,

Regards

Aenima

Probably OK by now. As with everything, when something is wrong EVERONE complains. If it ok, you hear nothing instead. But of the 2 major retailers here in sweden only one has that tube. makes me think that the one that does´nt carry it knows about the "bug"

Probably only my own brain-ghost on the last point. =D

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