[syousef]

Hi,

I'm hoping someone with a bit more experience than me can answer whether I should be concerned. I bought a Bintel 12" (GSO) dob on Saturday, checked and slightly adjusted collimation, attached locking castors yesterday, and finally got a view through it today. I've had an 8" since 2000 and a 10" since 2002/2003 sometime, so I'm not completely unfamiliar with scopes but i do not observe as much as I'd like to.

I used the supplied 26mm 2" to align a Rigel Quikfinder tonight, so that happened to be what I had when I first pointed the scope at Saturn. For about 5 minutes I was quite worried. I saw the most horrible ghost/double image of Saturn I've ever seen. Both images equally and dazzlingly bright. Using the aperture mask dimmed the image and eliminated the reflections. I checked collmation with a laser collimator, and while it wasn't perfect it was pretty close (within maybe 3-4mm on the center ring - assuming that's correctly positioned - and perhaps 4mm out reflected back onto the collimator). I tried throwing a bright star out of focus - it too seemed to double when viewed in focus - out of focus no hint of diffraction rings - seeing a complete mess. Fainter stars still seemed point like in focus but anything particularly bright was awful.

So I tried my 15mm GSO Superview, barlowed and unbarlowed and the ghosting was no where near as bad. Even switching back to the 26mm - while the ghosting was still there was not as bad!?

So I turned to other objects. The Jewel box being my favourite I got the increased detail I'd expect moving up 2" and having a newer mirror. I was able to make out what Stellarium is telling me was a magnitude 14.6 star with averted vision (but of course it wouldn't surprise me if it was variable). I was making out stars that didn't show up in Stellarium. All nice and point like, no issues. Very pleased. One look at mars confirmed the seeing was still a mess. Total mush - even considering it's on the opposite side of the sun this was horrible.

Getting back to the ghosting on the bright planet Saturn, before I bother the folks at Bintel, was it just the seeing causing issues? Or should I be worried I have issues with my mirrors or the mechanics? Am I just not use to a larger brighter instrument? Should I just be sticking to 1.25" for planetary viewing.

Thanks for reading...