Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Astro-Physics SLOWMAX versus FASTMAX

  • Please log in to reply
7 replies to this topic

#1 MDRP

MDRP

    Explorer 1

  • -----
  • topic starter
  • Posts: 75
  • Joined: 11 Aug 2015

Posted 04 December 2018 - 03:58 PM

The soon to be shipped Astro-Physics 10" f/14.5 Maksutov-Cassegrain I will call SLOWMAX (because of its focal ratio) offers the opportunity to contrast its performance with another exemplary AP Mak offering, the rare 7" f/4.5 Maksutov-Newtonian FASTMAX with its over three-times faster focal ratio. The scopes are similar in length without dewcap (both 29.5") with SLOWMAX about 5 lbs heavier with dew shield, and of greater tube diameter (11.6" carbon fiber versus 9" aluminum). Both have state-of the art coatings and are permanently alligned. Aside from optical design (Mak-Cass versus Mak-Newt), they differ most in focal ratio (f/14.5 versus f/4.5) and focal length (3683 mm versus 810 mm). Being compact, both can ride on the AP Mach 1 and perhaps even a DM-6, the grab-and-go option. Elsewhere, I have praised the virtues of the 180 FASTMAX as an all-round instrument capable of both contrasty, low-power, wide-field (23x, 2.7 degrees with Pan 35) and high-power views.  I have not changed my mind. Think 6" apo in a stubby tube. Although presumably optically exquisite, the SLOWMAX is a very different beast, boxed in by long focal length to higher power, narrower, fields (105x, .6 degree with Pan 35)--your once medium power eyepieces are now for moon and planets. Think 10" Clarke refractor. Of course, with this 10" aperture and great focal length come greater light-gathering and resolution. Residing under the East Coast light dome with its iffy seeing, I find 10" to be a good size, having built three classical Newtonian variants. I look forward to contrasts between Slowmax and Fastmax on deepsky targets, many of which start to be most interesting beyond 100x. Aside from reduced ability to use the SLOWMAX as its own finder, my high-power deepsky adventures hold promise. 

 

Regarding the famous AP wait lists, both FASTMAX and SLOWMAX were the rewards of 20 years of wating.   


  • Paul G, Paul Morow and jjack's like this

#2 Paul G

Paul G

    Cosmos

  • *****
  • Posts: 8260
  • Joined: 08 May 2003
  • Loc: Freedonia

Posted 04 December 2018 - 07:21 PM

Congrats!



#3 Erik Bakker

Erik Bakker

    Fly Me to the Moon

  • *****
  • Moderators
  • Posts: 7455
  • Joined: 10 Aug 2006
  • Loc: Netherlands, Europe

Posted 05 December 2018 - 03:56 AM

Congrats on getting another wonderful scope!

 

Coming from a Questar 7, I will say that an A-P 10" f/14.5 scope is not a good marriage with a DM6.

 

Incidentally, I've observed with a 266mm f/15 Alvan Clark refractor for many years and I think you're spot on with likening the new A-P 10" MCT to a 10" Clark. I do expect the 10" A-P to show more on any object that its it's field of view. But make no mistake, these are long focal length instruments, best used at 100x or even 200x and up. Regardless of stubby tubes wink.gif

 

I feel these long focal length, large aperture 10" scopes are best at home in an observatory on a very stable mount, bringing joy soon after you open up the roof and supporting their ability to magnify.



#4 JohnH

JohnH

    Mercury-Atlas

  • ****-
  • Posts: 2869
  • Joined: 04 Oct 2005
  • Loc: Squamish BC Moved!!!!!

Posted 06 December 2018 - 01:49 PM

The soon to be shipped Astro-Physics 10" f/14.5 Maksutov-Cassegrain I will call SLOWMAX (because of its focal ratio) offers the opportunity to contrast its performance with another exemplary AP Mak offering, the rare 7" f/4.5 Maksutov-Newtonian FASTMAX with its over three-times faster focal ratio. The scopes are similar in length without dewcap (both 29.5") with SLOWMAX about 5 lbs heavier with dew shield, and of greater tube diameter (11.6" carbon fiber versus 9" aluminum). Both have state-of the art coatings and are permanently alligned. Aside from optical design (Mak-Cass versus Mak-Newt), they differ most in focal ratio (f/14.5 versus f/4.5) and focal length (3683 mm versus 810 mm). Being compact, both can ride on the AP Mach 1 and perhaps even a DM-6, the grab-and-go option. Elsewhere, I have praised the virtues of the 180 FASTMAX as an all-round instrument capable of both contrasty, low-power, wide-field (23x, 2.7 degrees with Pan 35) and high-power views.  I have not changed my mind. Think 6" apo in a stubby tube. Although presumably optically exquisite, the SLOWMAX is a very different beast, boxed in by long focal length to higher power, narrower, fields (105x, .6 degree with Pan 35)--your once medium power eyepieces are now for moon and planets. Think 10" Clarke refractor. Of course, with this 10" aperture and great focal length come greater light-gathering and resolution. Residing under the East Coast light dome with its iffy seeing, I find 10" to be a good size, having built three classical Newtonian variants. I look forward to contrasts between Slowmax and Fastmax on deepsky targets, many of which start to be most interesting beyond 100x. Aside from reduced ability to use the SLOWMAX as its own finder, my high-power deepsky adventures hold promise. 

 

Regarding the famous AP wait lists, both FASTMAX and SLOWMAX were the rewards of 20 years of wating.   

Does anyone have the optical formula for the 180mm f/4.5 FastMak?



#5 MDRP

MDRP

    Explorer 1

  • -----
  • topic starter
  • Posts: 75
  • Joined: 11 Aug 2015

Posted 06 December 2018 - 05:03 PM

The 180mm f/4.5 Fastmax is an all-spherical Mak-Newt design. 



#6 jjack's

jjack's

    Messenger

  • -----
  • Posts: 446
  • Joined: 01 Apr 2012
  • Loc: normandy

Posted 06 December 2018 - 05:45 PM

Compact, small obstruction, contrasty, it can give wide fields to high powers. Good !

Only one drawback : the weight. maybe the price too.



#7 macdonjh

macdonjh

    Gemini

  • *****
  • Posts: 3449
  • Joined: 06 Mar 2006

Posted 07 December 2018 - 11:42 AM

 

I feel these long focal length, large aperture 10" scopes are best at home in an observatory on a very stable mount, bringing joy soon after you open up the roof and supporting their ability to magnify.

That's how I use my 14" f/15 classical Cassegrain.

 

Congratulations, MDRP, for your new scope.  Glad you had your Mak-Newt to hold you over while waiting for your Maksutov Cassegrain.  Twenty years is a long time.



#8 MDRP

MDRP

    Explorer 1

  • -----
  • topic starter
  • Posts: 75
  • Joined: 11 Aug 2015

Posted 07 December 2018 - 01:52 PM

I look forward to the arrival of "Slowmax" to contrast with the lovely and versitile Fastmax. Curiously, both involved a 20 year wait. I got on the 10" Mak-Cass list in 1999. My relation with Astro-Physics is long term. I was an early customer from the mid-1980s when I bought their 6" f/8 apo for $1295.


  • Paul G and Erik Bakker like this


CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics