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Mid 80's C8 as bad as Dynamax 8 ?

catadioptric classic optics SCT
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79 replies to this topic

#76 clamchip

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Posted 10 August 2019 - 07:57 PM

There must be a way to correct for SA at the focal plane and remove the corrector.

I guess it will require mirrors though, to bring all rays to a common focal point, a parabolic surface somewhere

in the system.

I wonder if it can be done electronically after the optics.

Your probably right, just make a new corrector. 

 

Robert



#77 davidc135

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Posted 10 August 2019 - 08:20 PM

The primary produces 20ish waves of S.A although the secondary reduces this by maybe a quarter. So any alternative to the corrector is a tough one.  David



#78 Bomber Bob

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Posted 10 August 2019 - 09:17 PM

Well, just me, but whether it's a C8, or a DX8, or a 2080:  If it stinks for planetary, but is OK for nebulae, accept it for what it can do, or get rid of it.  Disappointing as my DX8 was above about 150x, if Criterion had made an optional Golden Pedestal + Wedge for it (like the Questar Tri-Stand), I might've kept it for DSOs -- and as a beautiful Classic display.  Heavy as it was, I'd prefer it to a new China-made 8" Dobson, or a Cave 8" EQ rig.


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#79 starman876

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Posted 11 August 2019 - 08:13 AM

Well, just me, but whether it's a C8, or a DX8, or a 2080:  If it stinks for planetary, but is OK for nebulae, accept it for what it can do, or get rid of it.  Disappointing as my DX8 was above about 150x, if Criterion had made an optional Golden Pedestal + Wedge for it (like the Questar Tri-Stand), I might've kept it for DSOs -- and as a beautiful Classic display.  Heavy as it was, I'd prefer it to a new China-made 8" Dobson, or a Cave 8" EQ rig.

I would prefer something old and good like me gramps.gif



#80 highfnum

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Posted 11 August 2019 - 12:48 PM

Note on stacking software:

The primary purpose was to mitigate effects of 'seeing"

by stacking many short exposures and sorting those images 

and applying lucy-richardson formulas when can tease out hidden details

 

this method was actually used by large observatories until real adaptive optics was developed

and was originally know as post-adaptive processing

 

I'm not sure if this software method can "fix' optical errors(I doubt it)  - although that's a real and I mean real interesting idea

 

it would be cool if you could take a DPAC image of your optical system  and feed that as a matrix of points to software 

the software would then generate and inverse matrix (think of a corrective optic) that would correct those errors

(I do not know if this is possible but still a cool idea) 

 

I do know that for a short time before Hubble SA problem was fixed  they(NASA?) had used some kind of corrective software to fix simple SA

to some degree of success (however it must of been limited- because everyone wanted a true physical fix) 




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