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Difference between 5" and 8" mak/cass/sct

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#1 Jukka Tikkanen

Jukka Tikkanen

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Posted 11 October 2005 - 02:38 PM

Hello fellow stargazers,

Just pondering would it be worth the money and trouble to upgrade my 5" mak-cass to 8" mak-cass/sct/....
I would like hear from somebody else's experience about the the difference in aperture . How big is the practical gain in aperture?
I would appreciate if somebody could give me some kind of estimates about this.

Thanks in advance,

#2 bierbelly


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Posted 11 October 2005 - 02:45 PM

I can tell you that there's a huge difference between what I can see in my 8" MakNewt as compared to my 6" MakCas. The 8 will resolve many individual stars in M13, whereas the 6 struggles to resolve just a few.

#3 stevie



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Posted 11 October 2005 - 04:06 PM

i agree with bierbelly here
image brightness should be obvious too

#4 ezrider23



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Posted 11 October 2005 - 11:00 PM

The prices start rising steeply above 6" of aperture in a mak cas. I think a 8" newt would would do you well on planets especially with a curved spider and flocking, unless money is not an issue.

#5 Sherk


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Posted 16 October 2005 - 12:20 PM

76.2mm more in diameter less the increase in diameter of the secondary plus a lot of $... as usual I'm lost in these computations but as you are considering different styles of optics, perhaps a Tal 200K or Tal 250K might be your solution. And if you can get it in Kaliningrad, the price might be OK.


Or make that Königsberg for the nostalgics. :roflmao:

#6 HoO-Germany



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Posted 16 October 2005 - 02:41 PM

Hi Tikkis,
I agree with the writers before.
you will become in the 8" Mak-Cass more light to can split some stars more in closed clusters, you will get on planets more details on surfaces and also on planetary nebulas you will see more.


#7 rszabo


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Posted 16 October 2005 - 06:26 PM

I remember seeing M51 one night through both a 5" sct and my 7" Mak. Through the 5", you could see M51 as a faint smudge. It was visible through the 5", but all I could see was a blurry patch of faint light. Through the 7", you could make out spiral structure and see a fair amount of detail. I think the difference would be even more noticable in a 8" Mak.

However, there is something to be said for the portability of the 5".

#8 Oldfield


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Posted 16 October 2005 - 10:51 PM

somehow 8" is a magical size, the next step is 12.5".... so the difference is significant if you go from 5" to 8".

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