Star Shape on a F4 Newtonian

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Kostas Papageorgiou avatar
Hello.
I have a couple of months a SW Quattro 8".
After alot tries to collimate ny scope i resulted to this image below...
I use a SW Alphamatic coma corrector and i have collimated my scope with laser and a cheshfire... i think that the smaller stars look like oval to me... can you spot the problem? is the collimation? the guiding? tilt?  
I tracking with a SW EQ6-R PRO and a 50mm guide scope(180 focal length)..
maybe it is me... 
thanks.
Kostas.
glennb44 avatar
That looks very good.  Maybe you could post a magnified pic. of the problem stars. 
Basic collimation and coma correction are good but do check collimation at high power.  Have you seen this http://www.astrophoto.fr/collim.html

GlennB
Kostas Papageorgiou avatar
thanks for the answer.. i would check the guide. thanks.
here is a close on left.


here is on right ..
andrea tasselli avatar
Nothing out of the ordinary there. Just a bit a spherical due to the coma corrector. The elongation is more likely due to guiding.