First light (ish) - Help debug my ST4K/GSO RC10 tarantula test shot
Well the ST4K is new to me anyway so it rained for a week (sorry folks!), but cleared up last night, conditions were not so great, high cloud around and shooting into the south is towards Sydney from here. This is a stack of 16x5 min shots. I have had to resize to fit under the 200kb limit but am happy with this result, the camera is quite sensitive and clean.
One thing this shot does show is that I have one corner out of kilter,
I think it is collimation issue but would like a second opinion...the top left corner is the worst and has stars that are distorted like this -> \ ie elongated radially, it looks a bit like field curvature but the bottom corners look ok. Top right is also a bit off also showing a \ shape which for that corner is not radial.
So how should I proceed to debug this? I had no FR or filers in line so the scope was at its native F8 and the image scale is 0.75" per pixel.
Sorry should have said - the focuser is a Moonlite stepper - very solid. It can be collimated but generally they do not need it as far as I am aware...
True they should not need collimating and to do so would ruin your rotation. However, most of the GSO RCs require a collimation ring so that the focuser can be aligned. Do you have a collimation ring?
Hi Glen, no I do not - yet. But having just had a look at the ccd inspector result it would seem I have got a tilt problem and the ring is the best way to get rid of that I believe. If I am reading this chart right my collimation is off a little but my ccd is a good way off orthogonal to the light path so the first thing to fix is the tilt...
