90 replies to this topic

[rob1986]

8, 10, 12, 16 all make good sense

But 9.25 and 11??? Especially as the origional celestron cats also came in even steps

[CHASLX200]

They always tried to out do each other. Meade was the real deal until the later 90's when cost cutting took them downhill fast. They had the world changing LX200 in late 1992 while Celestron lagged behind. Optics wise i had more bad SCT's from the big C vs Meade but had more freaky sharp SCT's from Celestron. Only duds from M was three 4" 2045's that were total mush bombs and M did not even make them.

[quilty]

I'd like to know specially why those odd 9 1/4
I sent them an email how they invented that odd size but got no answer
Making sense would be like

2
2.5
3
3.5
4
4.5
5
6
7
8
(9)
10
12
14
16
20

but no 9.25 or 12.5. 12.5 cm makes 5 inch but no 12.5 inch make 50 cm

And what about 13"? Does that aperture size display antimatter only?

Edited by quilty, 30 May 2024 - 08:38 AM.

[Jim45157]

i had a lx90 and it was not very good 

[12BH7]

i had a lx90 and it was not very good 

I have an LX90 and it's excellent.

[bobhen]

8, 10, 12, 16 all make good sense

But 9.25 and 11??? Especially as the origional celestron cats also came in even steps

Actually, Celestron had 5", 8", 11" and 14" SCTs. In that group, the 11" was the last added.

 

I think Celestron's choice of a 3" difference between sizes makes more sense than Meade's 2" difference. A 3" difference is more meaningful, in that it's a big enough jump to make the light gathering and resolution increase in the bigger size telescope and additional cost worthwhile. 

 

Maybe someone who worked at Celestron would know why they developed the 9.25". I can only guess that Celestron wanted to offer something different between Meade's 8" and Meade's 10" SCTs.

 

Bob

[RAKing]

I haven't looked at Robert Piekiel's CD in a while, but whoever designed the C925 deserves a medal!  

 

I have owned two C925s over the years and they were all better than the regular SCTs.  If the secret was the slightly longer primary focal length, it certainly worked very well.  I had a better field at the edges with a regular C925 SCT than with anything other than an HD-Edge, or the Meade ARC design.

 

My old 10-inch Meade ARC (before the threatened lawsuit forced them to change it) was an excellent SCT, but it was much heavier than the C925, and I preferred the slightly smaller cat.

 

My .02,

 

Ron

[quilty]

but you agree it's not due to the 0.25 plus aperture size?
They copied the TSC 225 by half. The TSC is probably better with just 29% CO. It has an f/3 primary and a 4x sec. mirror.
Maybe the 0.25 was just to make it virtually better than the TSC.

Edited by quilty, 30 May 2024 - 09:08 AM.

[Echolight]

I know why the 8 is offered by both, and is the most popular.

[Jon Isaacs]

Actually, Celestron had 5", 8", 11" and 14" SCTs. In that group, the 11" was the last added.

 

I think Celestron's choice of a 3" difference between sizes makes more sense than Meade's 2" difference. A 3" difference is more meaningful, in that it's a big enough jump to make the light gathering and resolution increase in the bigger size telescope and additional cost worthwhile. 

 

Maybe someone who worked at Celestron would know why they developed the 9.25". I can only guess that Celestron wanted to offer something different between Meade's 8" and M""eade's 10" SCTs.

 

Bob

 

When were the 5", 8", 11" and 14" Celestrons introduced?

 

Didn't these Celestrons precede Meade entering the field?

 

Jon

[rob1986]

I think the 11 was an answer to meades 10

[Bill Barlow]

I believe the C9.25 was developed mainly for imagers.   Something about the optical design of a larger CO and slower primary and secondary mirrors would illuminate a full sensor camera?  But it turned out to be a very good visual telescope as well.

 

Bill

[quilty]

They don't tell. First designed for imaging with larger CO and less coma. Maybe the plus 0.25 to best the TSC and compensate the larger CO.
Or, that was my initial guess, one of them engineers is a Harry Potter fan

[rob1986]

I wonder if it proceeded the 11. It seems both were designed for the ultima

If so, they may have tried to best meades 10, found stability insufficient and so calculated a largest ota that would work.

Edited by rob1986, 30 May 2024 - 10:37 AM.

[quilty]

I think the 11 was first and then they filled the gap. When you consider light grasp the 9.25 is not quite in between, that would be 9.6
Nevertheless I want a true reason for that odd size :-)
square 8 plus square 11 divided by 2 yields 92.5, its root is 9.6, that would be the mean diameter at light grasp. At diameter it was just 9.5

Edited by quilty, 30 May 2024 - 10:50 AM.

[Pat Rochford]

When were the 5", 8", 11" and 14" Celestrons introduced?

 

Didn't these Celestrons precede Meade entering the field?

 

Jon

 

The C-8 was introduced in 1970, the C-5 in 1971, the C-14 in 1972.  Best I could find on the C-11 was 'early 80's and the C-9.25 was 'early 90's.  I'll keep looking.

[RAKing]

When were the 5", 8", 11" and 14" Celestrons introduced?

 

Didn't these Celestrons precede Meade entering the field?

 

Jon

 

Meade didn't start building SCTs until 1980.  Celestron already had a full lineup.

 

The Takahashi 225 SCT was a great scope, but IIRC, the person responsible for the mirrors passed away, and Tak stopped the project after the first run.

 

Ron

Edited by RAKing, 30 May 2024 - 01:12 PM.

[Pat Rochford]

Okay, according to Company Seven:

 

C-11 introduced in 1980.

 

Comet Catcher introduced in 1983 (I know ... it's a Schmidt Newtonian but hey, the information was right there so ...)

 

C-9.25 introduced in 1996.

[Pat Rochford]

According to the introduction in a 2003 - 2004 Meade catalog I have:

 

"With the announcement in September 1980, of the model 2080, Meade Instruments began to grow rapidly.  Each year thereafter saw new and exciting models ..."

 

Reading this it would appear that the 10" Meade SCT followed the 11" Celestron SCT. 

[rob1986]

So says uncle rod. But not by much. Both were introduced by 1980. I still think the 9.25 must have been designed to the maximum load of the ultima fork.

[Pat Rochford]

So says uncle rod. But not by much. Both were introduced by 1980. I still think the 9.25 must have been designed to the maximum load of the ultima fork.

 

If you're referring to the Celestron 11" and Meade 10" then you are in disagreement with Meade's catalog.  

 

I don't know what or if Rod has mentioned about these dates.

[rob1986]

Fine internet search gives 1982 for the 2120

[CHASLX200]

I have an LX90 and it's excellent.

They all vary from every year. This is a lotto.  I am taking a big chance on a used C11 this weekend. Can i get real luckyyyyyyyyy and get 3 freaky sharp SCT's in a row?

[CHASLX200]

Actually, Celestron had 5", 8", 11" and 14" SCTs. In that group, the 11" was the last added.

 

I think Celestron's choice of a 3" difference between sizes makes more sense than Meade's 2" difference. A 3" difference is more meaningful, in that it's a big enough jump to make the light gathering and resolution increase in the bigger size telescope and additional cost worthwhile. 

 

Maybe someone who worked at Celestron would know why they developed the 9.25". I can only guess that Celestron wanted to offer something different between Meade's 8" and Meade's 10" SCTs.

 

Bob

Worst ever SCT was my friends mint 1982 C11 he got in 1999.

[CHASLX200]

When were the 5", 8", 11" and 14" Celestrons introduced?

 

Didn't these Celestrons precede Meade entering the field?

 

Jon

They had the odd ball sizes in the 1960's off all kinds. The C8 and 5 and 14 came out around 1971.  The 11 around late 80. Meade started way after C did around 1980. C had the 8-10-12-16 and 20 and 22 in the 60's. Then they had a 4" and that one off odd ball scope that i don't they ever really made.

Edited by CHASLX200, 30 May 2024 - 06:20 PM.