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Hi Geoff,
Seems the inside tube diameter was off, should be 235-237mm not 230mm and this fixed the problem of "Vignetting of 75% ray at front aperture".
The field marked "spare focuser in travel" was wrong too.
Can i please confirm that when calculating "to front of tube" and "to back of tube", this includes the metal parts that screw into the front (holding spider/secondary) and back (holding mirror) and not the actually tube without these?
Also there is a 35mm high 1.1/4" adapter should this be included in the "focuser height" field? This must be the add 15mm odd you refer to?
75% Illuminated field is around 35-36mm. With little change unless inputting smaller secondary.
100% varies from 6-13mm depending on where i'm calculating focuser height.
Really appreciate your help btw!!!
Not a dedicated planetary scope but it is around 7 years old so thought a new primary mirror would be good, quite sure the current one needs re-coating anyway. While i was at it, figured why not upgrade the secondary.
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