Quote:
Originally Posted by glend
Thanks Paul. I have gone back to square one and started again on the focuser alignment and tightened the collimation ring right down and then adjusted from there - this seems to have solved the immeadiate problem; so it looks like one of the screws in the collimation ring was not as tight as it should have been. I can hold collimation with my uncooled DSLR but the cooled camera seems to be too heavy for the focuser assembly - still getting some sag. When using Liveview on the cooled camera, after centering the star I can move it on the screen with a simple touch on the bottom of the camera - not sure if this is causing a slight mount movement or if its the focuser. Perhaps it's better to not touch it at all.
Initial 5 minute 30 sec test shot on the Sculptor looked reasonable, but showed up slight elongation in the star field - which maybe guide/mount related. More tuning required.
I installed a Kendrick secondary heater and now I am thinking of removing it as it hangs over the side of the secondary shroud slightly and is thus in the light path. I tried to trim it before I installed it but it just does not fit right. The thick wiring is also a problem and even when taped to the top of the spider vane it is noticeable in a star test. I have the copper adhesive strips that came with the heater but have not installed them. It (the wiring and overhang of the heater) doesn't seem to be affecting the test image however, so is it worth worrying about?  |
Most likely the assembly of the focusor is causing the movement you see on live view. Until you can be certain that the elongation in the stars is caused by the guiding it will be hard to say with any certainty, but if you have good shaped stars after 30 seconds, it is most likely guiding causing the elongation.
With the secondary heater I taped the wiring one on top of the other and that is on top of one of the vanes of the secondary assembly. It causes a slight thickening on one of the diffraction spikes. I simply used electrical tape and it has held well for nearly 2 years now.