Takahashi TOA-130NS tube rotation

[David_W]

Hi Guys,
I wonder if anyone can help me here. I just set up my new TOA-130NS on the balcony, and while lifting the tube out of it's box the front end of the tube rotated slightly independently of the back.

It's as if the tube can be unscrewed, with the join being where the dewshade retracts to.

Have any of you heard of this? Is this something I should be worried about? I did a quick search on google about this but couldn't find anything. I'm a bit worried this motion will put the lens out of alignment.

Cheers,
Dave W

Bruce ACT.

[Hans Tucker]

Hi Dave,

From what you describe it looks like the complete lens cell assembly may have come loose from the tube. If you retract the dew shield back as far as it will go so you can try and grab hold of the outer fixed housing portion of the lens cell from inside of the dew shield, without putting finger prints or smudges on the lens, you might be able to secure it. Alignment of the objective elements should not be affected as alignment is controlled via three collimation screws on the lens cell. On another note are you sure the dew shield hasn't just rotated.

[David_W]

Hi Hans,
Thanks for the message, but I'm not sure if it is the lens cell as it is the whole tube that is rotating, rather than something inside the tube. If I twist the front part anti-clockwise, it tightens up again. I'm not willing to try, but it does look like the tube can be unscrewed..?

Comforting to hear it shouldn't be affecting the lens, I've had nothing but superb images with this telescope since buying it, I even split eta Geminorum, a first for me.

Thanks again.

Dave W

[peter andre]

Hi Dave,
I agree with Hans, but perhaps you can get in touch with your dealer who sold you the scope, first!
They can get in touch with Takahasi Japan the same day to solve your problem quickly.
good luck,
Peter

[RickS]

It might also be worth asking on the Yahoo "UncensoredTakGroup": http://tech.groups.yahoo.com/group/UncensoredTakGroup/

There are some very knowledgeable folks on there, including the US Tak distributors.

Cheers,
Rick.

[Exfso]

As Hans said are you sure it is not just the dew shield that has rotated?? to check this, tighten up the two thumb screws that lock the dew shield, if nothing rotates then, I would suggest you have only rotated the dew shield, which is meant to move around.

[Hans Tucker]

Is the TOA-130NS a split tube design like the FSQ-106N? Dave does your scope have a seam running around the tube just below the dew sheild. It maybe a left hand thread and simply taking the to halves in each hand and firmly rotating anti-clockwise will tighten the tube. If it was an FSQ-106N that you had I would be cautious doing this but because the lens elements are up front in a TOA tightening the tube halves will not affect the alignment.

[David_W]

Hi Guys,
Thanks for all the responses. There is indeed a seam on the tube at the same place where the lens shade retracts back to, about 6 inches behind the location of the lens cell. This seam is where the tube can twist, so it does look like it's a split tube design. I tightened it up again by twisting anti-clockwise as you suggested. Will keep my eye on it from now on.

Incidentally the seeing last night was terrible, so I didn't reign long on my balcony. I had intended to try to split Sirius, never managed it yet.

I'm moving to Bungendore NSW in a week, should get darker skies and better seeing from there, being away from an apartment block radiating heat will make a big difference.

Cheers, and all the best.
Dave W

:thanx:

[Waxing_Gibbous]

Tch!
If you'd bought MY TOA 130 you wouldn't have this problem! :D
Its not strictly a 'split tube' design. More like it can be disassembled - if that's any clearerer. Apart from the elements in the cell, the whole tube assembly CAN just be unscrewed. In some respects this is a good thing. It makes for a very tight seal, and simplifies 'home maintainence'
Anyway. Don't worry. You are not the first to get a 'loose' Tak and you probably won't be the last.
As Hans correctly points out, it should not affect the optical performance providing collimation is OK.

[gregbradley]

The TOA design is an triplet with a wide air space gap between I think one of the lenses. That is why it has a split part way down the tube. I assume that is where that 3rd wide air spaced lens is.

I would simply retighten the tube as it most likely is merely the tube was loose and simply tighten it.

I do believe collimation is critical with the TOA design and is perhaps one reason why others don't copy their design. It requires precise engineering to keep that 3rd lens just perfect. But as pointed out the collimation wouldn't be done by merely screwing the lens cell, that would be adjusting the lens in its lens cell with the collimation screws on the lens cell. Something, I imagine, would be a big mistake to adjust yourself at home.

Greg.

[Exfso]

I have a TOA130 and there is no way under the sun that I would attempt to mess with the collimating screws. These scopes require specialist equipment for collimation. As far as I know only Takahashi themselves and Takahashi America or TNR are the only people geared up to collimate these scopes. You will note that you can buy a Takahashi collimating scope, which is supposed to be for collimating their refractors, but I believe it will only work with the FS series of refractors, I have been told by the guys at TNR that these collimating scopes do NOT work with the TOA series. As Greg has said, the front cell which consists of the 3 elements is a separate entity to the rest of the ota, and is housed in the part that has come loose, just tighten it up, and I am sure you will find it will be ok. Any doubts though, contact the guys at Takahashi America, they are excellent to deal with. Art Ciampi and Fred are the two in question. They can be contacted via the Takahashi uncensored Yahoo user group. :)