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Which 8" Newtonian for EAA

Beginner EAA Equipment
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#1 JTNX01DC

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Posted 18 October 2021 - 08:16 AM

I'm looking to get a scope for EAA. Settled on 8" imaging newtonian.

Any opinions on these options ranging $325 to $700 ?

SkyWatcher Quattro F/3.9  $695

Apertura F/4  $500

Astro-Tech F/4  $500

GSO F/4  $329

Tks tons for your input!



#2 MartinMeredith

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Posted 18 October 2021 - 08:26 AM

I use the Quattro as my sole EAA scope and can recommend it, though I've not compared it to anything else. I modified the secondary adjustment knobs, added some washers, and plenty of flocking. Mine's the carbon fibre model.

 

With any of these fast reflectors you really need to cost in a decent autocollimator.

 

If you've settled on a scope I assume you've also decided on suitable cameras, because for EAA the two need to work together e.g. ability to reach focus, good arcsec/pixel etc.

 

Martin


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#3 JTNX01DC

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Posted 18 October 2021 - 11:30 AM

I have a ZWO 294MC Pro camera. Hope that's good.



#4 MartinMeredith

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Posted 19 October 2021 - 06:00 AM

The 294 looks like a good fit in terms of arcsec/pixel. I use a small sensor so coma doesn't affect me (much) but you might also want to budget for a coma corrector for a larger sensor. I hope others who use larger sensor cameras with Newts will comment.

 

Martin



#5 alphatripleplus

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Posted 19 October 2021 - 07:09 AM

I don't have a fast Newt, but I wonder if with a larger sensor camera like the 294 vignetting may be an issue? That may depend on the size of the secondary and/or the width of focuser tube. If it is an issue you can utilize flat frames to remove the effects of uneven illumination across the frame.


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#6 Tiago Ferreira

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Posted 22 October 2021 - 04:28 PM

No vignetting with my 8" Dob and ZWO 294 so far

No coma but it's an f/6. I will lower the focal ratio to see how it goes but didn't have opportunity yet. It's a new telescope...



#7 cmooney91

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Posted 25 October 2021 - 10:02 AM

I use a bresser 208mm F3.9 (same mech. and optics as ES) with a ASI294MC and SW Quattro Coma corrector. 

 

Here is a flat frame from my combo, the darkest corner is ~75% illumination which is only ~1/3 mag.  It calibrates out no problem, and the coma corrector gives sharp stars to the corners(when collimated).  



#8 alphatripleplus

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Posted 25 October 2021 - 03:49 PM

The  Quattro coma corrector adds a fair amount to the total cost ( another $375), but may be worth it if you want those sharp stars in the corners of the big sensor. smile.gif




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