I just bought a new C6/Evo ( grab 'n' go) setup and wanted to perform a Star Test to determine the quality of the optics. I waited until this morning when conditions were stable and with good transparency.
*** I've been reading the excellent book 'Star Testing' by Suiter to give me insight.
Aug 15th, 4:00am
Star selected: Algol (2.12 mag) high in the sky.
C6/Baader Maxbright Star prism diag./ Baader BHZ MKIV @ 187X/cool down 2 hrs.
0) Collimation: VG - Excellent
1) Snap-test: 'excellent'... pin point star image (only a 'hint' of a surrounding defracation ring). This gave me GREAT happiness...
2) Inside / Outside focus: nearly perfect same defracation pattern on BOTH sides of focus. This result again gave me high hopes for this little SCT. This result, performed 10-15 times, was consistent and supported the 'snap test' result.
3) Misslignment: None detected
4) 'Seeing': Steady/Stable
5) Pinched Optics: None detected
6) SA: Very slight undercorrection (between 1/4 wave and 1/8 wave images in Suiter's book).
7) Roughness: Absolutely smooth defocused concentric image from CO to 'edge'.
8) Turned Edge: None detected
9) Astigmatism: None detected
Overall, based on Suiter''s images for a 'perfect optic' SCT it seems this new C6 is some were between 1/6 wave to 1/8 wave precision optically based on last night's star testing.
Question, "Am I performing the Star Test correctly, and do you agree with my initial estimate of 1/6 to 1/8 wave optics?"
I'm contemplating getting a Ronchi EP to further test this and other scopes.
Any comments/insight are very welcomed... and more testing will be conducted in near future.
Edited by AJK 547, 15 August 2019 - 09:59 AM.