Anonymous
Unregistered
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Hey everyone. New to the forums and am looking to find out what everyone is saying  . What do the acs Mak and Cat stand for? And any other info you can throw my way will be helpfull when I surf your grand forums.
Thanks
Buddha(Chris)
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Anonymous
Unregistered
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guess I could have read the forum info and saved a post...now what exactly do they mean?
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summitlake
scholastic sledgehammer
Reged: 09/05/03
Posts: 878
Loc: Castro Valley CA
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"CAT" is short for catadioptic, meaning loosely any of several similar telescope designs with front lens, rear reflector combination and a folded light path. Examples are Schmidt-Cassegrain telescopes (aka "SCT"), and Maksutov ("Mak").
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Alex
Meade LX90 8" SCT
Orion 127mm Mak
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jrcrilly
Refractor wienie again
Reged: 04/30/03
Posts: 22364
Loc: NE Ohio
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What Alex said.
I can expand a little. Usually when we say "Mak" we mean Maksutov-Cassegrain but there are other flavors, like Maksutov-Newtonian.
You know a Newtonian has a parabolic mirror which reflects light back toward the opening, where a flat secondary mirror redirects it sideways and out through a hole in the tube to an eyepiece. A Cassegrain starts out similarly but the secondary redirects the light back toward the primary mirror, where it exits through a hole in the primary and goes to the eyepiece. Since the secondary is nearer the primary (one half the light path) it must be larger than in a Newt and since it blocks incoming light that makes it an unpopular configuration. Common variations on the Cassegrain include the Schmidt-Cass and the Maksutov-Cass.
Schmidt changed the primary mirror to a spherical one and made it faster (about F/2) to reduce the required secondary size and tube length. The spherical mirror makes a corrector lens necessary at the opening to correct for spherical aberration. The short primary makes a curved secondary mirror necessary to make the telescope act like an F/10 or so instrument despite its short length and relatively small secondary.
Maksutov also modified the Cassegrain design by shifting to a spherical primary mirror which again requires a corrector lens but uses a sperical secondary which is usually ground onto the back of the corrector lens and silvered. I don't know the usual speed of the primary mirror but the end result is usually F/12 to F/15.
Schmidt
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John C
Urban Observatory
Tele Vue Pronto
A&M/Astreya 76mm F/6 APO
TMB/LOMO 80mm F/7.5 APO
Tak FSQ-106N F/5 APO
Meade 152ED F/9 "APO"
152mm F/10 achromat
Tak CN-212 8" F/12 classical Cass/ F/4 Newt
Teeter 20" F/3.8 truss Newt w/ServoCat
LXD750, EM-200, CI-700
ST-10XME
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rboe
Numbfinger
Reged: 03/16/02
Posts: 39489
Loc: Phx, AZ
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Didn't we start a TLA thread to explain some of the odd shorthand we use or was that the Yahoo forum?
We tend to toss these terms about like cotton candy, causing confusion about the newbies and me alike. 
What does ACS stand for? Celestron marketing term?
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Ron
NS11GPS
Pronto
16" dob
15X70 Obies
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jrcrilly
Refractor wienie again
Reged: 04/30/03
Posts: 22364
Loc: NE Ohio
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Quote:
What does ACS stand for? Celestron marketing term?
Yes; that one's not our fault! I think it stands for Advanced Computerized System.
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John C
Urban Observatory
Tele Vue Pronto
A&M/Astreya 76mm F/6 APO
TMB/LOMO 80mm F/7.5 APO
Tak FSQ-106N F/5 APO
Meade 152ED F/9 "APO"
152mm F/10 achromat
Tak CN-212 8" F/12 classical Cass/ F/4 Newt
Teeter 20" F/3.8 truss Newt w/ServoCat
LXD750, EM-200, CI-700
ST-10XME
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jrcrilly
Refractor wienie again
Reged: 04/30/03
Posts: 22364
Loc: NE Ohio
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Oops. I think I had that one wrong when I used it earlier. I believe it's "ASC" rather then "ACS". Still dunno for sure where they got it...
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John C
Urban Observatory
Tele Vue Pronto
A&M/Astreya 76mm F/6 APO
TMB/LOMO 80mm F/7.5 APO
Tak FSQ-106N F/5 APO
Meade 152ED F/9 "APO"
152mm F/10 achromat
Tak CN-212 8" F/12 classical Cass/ F/4 Newt
Teeter 20" F/3.8 truss Newt w/ServoCat
LXD750, EM-200, CI-700
ST-10XME
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Stacy
Carpal Tunnel
Reged: 09/15/02
Posts: 2076
Loc: The Great Northwest
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ASC = Advanced Series Computerized, but that's just a Celestron thing I believe.
Stacy
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NS11-GPS-XLT, XT-8, 120ST, AEX-10X50
www.darksky.org
Human history becomes more and more a race between education and catastrophe.
- HG Wells
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matt
Vendor (Scopemania)
Reged: 07/28/03
Posts: 10015
Loc: Chaville, France
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Quote:
Quote:
What does ACS stand for? Celestron marketing term?
Yes; that one's not our fault! I think it stands for Advanced Computerized System.
That's the Advanced Camera for Surveys, if you come across an ad saying ' 92"space telescope for sale'
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Matt
CI700 mount with various scopes on top.
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wilash
Fairy Godmother
Reged: 09/30/03
Posts: 5746
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A catadioptric lens (CAT) uses both lenses and mirrors to make an image. The order of the mirrors and lenses are not important. In the States, Schmidt and Makusutov cassegrain telescopes are very common and use a front corrector lens. But in Japan, Vixen uses a different approach. Their catadioptric telescopes have no front corrector. The lenses are placed in front of the secondary mirror.
Edited by wilash (11/10/03 08:24 AM)
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Victor Kennedy
Pooh-Bear
Reged: 05/22/03
Posts: 9798
Loc: Slovenia
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Some of the supplied definitions are worthy efforts, indeed, but the correct explanations of the most-used acronymns are:
CAT: Capable All-round Telescope
SCT: Superbly Compact Telescope
ACHRO: A Colorful Halo Round Objects
APO: Affluent Purchasers Only
DOB: Damn! that's an Oversized B____r!
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To err is human; to moo is bovine.
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jrcrilly
Refractor wienie again
Reged: 04/30/03
Posts: 22364
Loc: NE Ohio
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Quote:
Some of the supplied definitions are worthy efforts, indeed, but the correct explanations of the most-used acronymns are:
Excellent! Thanks for sorting us out on those, Victor! 
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John C
Urban Observatory
Tele Vue Pronto
A&M/Astreya 76mm F/6 APO
TMB/LOMO 80mm F/7.5 APO
Tak FSQ-106N F/5 APO
Meade 152ED F/9 "APO"
152mm F/10 achromat
Tak CN-212 8" F/12 classical Cass/ F/4 Newt
Teeter 20" F/3.8 truss Newt w/ServoCat
LXD750, EM-200, CI-700
ST-10XME
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