Starizona SCT corrector v3

[that_guy (Tony)]

Hi guys, after months of wrestling with my cheap GSO RC, I'm just about ready to give up on it. Looking for alternative methods looks like I have a few options. Sell the RC8 (for super cheap, and to someone with more patience than I) and buy the Starizona SCT correct v3 straight from the US ($600 or so delivered), sell the RC8 and sell my 8" evolution SCT and buy an 8" EDGE HD or save up for EDGE 9.25" after selling both scopes.
I have a few questions before making my decision. Is there a huge difference between the 8" and 9.25" EDGE HD? Also does anyone have any experience with the Starizona SCT corrector? I understand that the v3 is fairly recent but anyone have any experience with previous version (re. how it performs compared to the cheap meade/celestron reducer corrector?)

[multiweb (Marc)]

What's the issue with the RC? Those small GSOs are compact enough to be pretty good and easy to use.

[that_guy (Tony)]

I've spent the better part of two months getting it collimated but I keep getting strange abherations in the stars, can't seem to get round stars in all four corners as well. Had it looked at with the tak collimator as well and thought it was pretty good. It was an improvement but no where near the level I want it at.

[multiweb (Marc)]

Originally Posted by that_guy

I've spent the better part of two months getting it collimated but I keep getting strange abherations in the stars, can't seem to get round stars in all four corners as well. Had it looked at with the tak collimator as well and thought it was pretty good. It was an improvement but no where near the level I want it at.

Does it need a corrector?

[that_guy (Tony)]

Not for the Sensor size of the asi1600mm. I heard that sensors bigger than APSC is when you begin to need correctors.

[multiweb (Marc)]

So your stars aren't round on axis as well? Is that like oblong, trefoil?

[that_guy (Tony)]

looks like beans

[multiweb (Marc)]

that's very odd. maybe you've got pinched optics.

[that_guy (Tony)]

If I did, how would i go about fixing it? Are the collimation screws on too tight aroud the primary or does it require a more indepth tinkering.

[multiweb (Marc)]

Originally Posted by that_guy

If I did, how would i go about fixing it? Are the collimation screws on too tight aroud the primary or does it require a more indepth tinkering.

You need to first have a look how the primary is held on the baffle tube. If there is a retaining ring in front of it make sure it's not screwed on tight. If it presses on the glass of the primary if will stress the glass. Issues with secondary mirrors usually show up as trefoil shapes in the stars. If the secondary baffle tube is made out of aluminium and it's pressing on the side of the glass as well it could stress the glass.

So here's a couple of things you can start looking at mechanically.

PS: I googled your scope to see how it's made inside and there is a small retaining ring on the primary. Worth checking that first.