Hi,
Can any one advise me on a problem I have with the collimation of a 6"/f9 (150mmx1400mm) Newtonian.
It is a short tube and uses a corrector Lens (Glass) at the bottom of the focus tube to achieve the focal length.
I have tried to collimate this quite a few times now but still having problems.
I used a Celestron Cheshire/sight tube to allign the soundary, and a Saxon Laser as well, The only way I could align the main mirror was by removing the corrector lens (Jim Fly recommended to collimate without it in place). Every thing looks good but when tested on a star, I still do not get any leeway on the focus using a 25mm eyepiece. The image is either triangle in shape or ghosted - see two objects instead of one. (Mirror isd not pinched or not any more, as this was checked and fixed.) I noticed that if I rack the focus out the star colimation looks good but if I rack the focus in I get a elongated object. I removed the corrector and reversed the lens in the holder and tried again but still have the same problem but in reverse????
I also have noticed if I have it in focus (well what I think is in focus) I see a double of the image but if I avert my eyes sometimes or if I look down through bottom edge of the eyepice the image will come good. ?????
This is really sending me crazy
, does any body have any suggestions besides getting rid of the telescope.????
Is the corrector lens flawed????
I can get this scope replaced by the maufacturer, as it is still under warranty, So far I have been under the assumtion that the initial problem when I recieved the telescope by courier was the optical train was out of alignment but if it is flawed then it has to go back.
I want to make sure before it goes back that it was not just the alignment or I will be charged a fee if not a warranty issue.
.
I have purchased one of Jim Fly's collimating Kits for a 1.25" and he has also put me on to a supplier of a Autocollimator for a 1.25" focuser which I will be buying at the end of the week
I am going to have so many collimating devices on hand soon that I will become an expert at it.
I just quckly tweeked my sons 6"/f5 and it is brilliant , even with a 2 x barlows and high mag lens (4mm) - amazing
. .................Yet this scope is from the same maufacturer as mine (next model down - cheaper price too) except the focal length dose not use a corrector lens