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Chances for a good C11: 50-50, 60-40, 80-20?

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#76 NMBob

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Posted 11 November 2018 - 11:46 AM

looks impressive.

 

The newer SCT from Celestron are much better. Ignore what you hear about the past from people who have no clue how to collimate an SCT.   Anyone who buys SCT after SCT and gets the same results tells me it is not the SCT's that person is buying.  On the other hand remember what Einstein said.  "The definition of insanity is doing the same thing over and over again, but expecting different results”

Being crazy could explain quite a bit around here. :)

 

I haven't had any trouble with the Edge 8 I got last year, and it came via the same way from the same place. It gets dragged all over the countryside and I don't think I've ever even adjusted the collimation. !!!

 

Ordered the Hotech SCT collimator. Starizona had it for $399, instead of $455 everywhere else, but oddly they didn't even list the HyperStar add-on so you can collimate the HS lens with it. Funny. Got that from AgenaAstro. I could very well be dangerous by next weekend, or at least prepared to get that way, or prepared to box it all up and send it back. :)



#77 jgraham

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Posted 12 November 2018 - 09:44 PM

My experience has been pretty much the opposite of what some have reported. I own more SCTs than I care to count spanning the period from about 1975 through 2010ish, hopping over the Halley years, and there's only one fair one in the bunch, the others are good to excellent. The later years are consistently very good. There is one consistent theme throughout; acclimation and colimation. To get the best performance out of these scopes the colimation needs to be spot-on. Close is not good enough. I have lost count how many SCTs that I have 'fixed' by dedicating an evening to zeroing in the alignment.
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#78 NMBob

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Posted 12 November 2018 - 11:13 PM

It'll be interesting to see what this Hotech system shows with all of my C8's. If I find out I could have been taking way better pictures with my Nikon FM and a Celestron cold camera all those years ago I'm going to be really mad. :)



#79 NMBob

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Posted 23 November 2018 - 04:44 PM

Got the replacement propeller for the front of the Edge 11 during the week and got it put on. Looks brand new.

 

Just got the Hotech SCT collimator. Dean at Starizona almost had me talked out of getting one. He said they may not work as well as expected for aligning the HyperStar lenses. He outlined a 'by eyeball' method with the secondary removed. I got the collimator anyway for my non-Fastar Celestrons if nothing else. I'll get it all set up tomorrow. Should be interesting.

 

I think Celestron is sending me another Edge11!? There's 45lbs of packages (2 of them) on their way from Yorba Linda. It all came in one 45lb package the first time, so I'm not sure what's going on. No one said anything about a new telescope. All I wanted was the plastic propeller. :)

 

Bob


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#80 dustyc

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Posted 24 November 2018 - 04:55 PM

Geez! Well, you could just send it back, or enjoy one of those rare chances to pick the best one? On the other hand since you modded the 1st one I guess the 1st option is better. Amazing though, that they sent you some more stuff. 



#81 starman876

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Posted 24 November 2018 - 07:46 PM

My experience has been pretty much the opposite of what some have reported. I own more SCTs than I care to count spanning the period from about 1975 through 2010ish, hopping over the Halley years, and there's only one fair one in the bunch, the others are good to excellent. The later years are consistently very good. There is one consistent theme throughout; acclimation and colimation. To get the best performance out of these scopes the colimation needs to be spot-on. Close is not good enough. I have lost count how many SCTs that I have 'fixed' by dedicating an evening to zeroing in the alignment.

I agree with you completely.  There are plenty of people who have complained about soft SCT's when it most likely was a close alignment and not a spot on alignment.  



#82 dr.who

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Posted 24 November 2018 - 08:41 PM

First, the EdgeHD 14's are the last Celestron scopes made in Torrance California. I know this for a fact because I have toured the factory and seen them being made. Sadly I wasn't able to take photos.
 
Second, the Edge series as a whole tend to be very well made scopes for a mass produced scope.  So the chances of getting a good one (at least diffraction limited) are very high. On the order of likely 90%+. 
 
Third, I have owned four EdgeHD scopes to date including the 14" I have now. They have all been diffraction limited. Including the 11".
 
Fourth, the TEMPest fans are an absolute must on them. In my experience it will cut cooling time by at least 40% if not 50% with the scope being usable to me for visual after 20 minutes on the 8", 30 minutes on the 11", and 45 minutes on the 14". By usable I mean stars that are somewhat small and not fuzzy flaring balls of light.
 
Fifth, when properly cooled and collimated a EdgeHD provides near APO refractor quality views to the edge of the field. 
 
Sixth, so many have problems with collimation and bothering to wait for the scope to properly cool which is where the majority of the bad reports come from. 
 
Seventh, those who change scopes like they change underwear are likely on a quest for unobtainium. There is no such thing as a perfect scope. There is bad, decent, good, and very good. Once you get into the very good range you are at the top of the heap. This is the area where Takahashi, Astro-Physics, and TEC are. But a 10" Astro-Physics Mak-Cass is $17,000+ USD *IF* you can find one. The current waiting list is getting notifications for the 1998-2000 year range. A TEC 10" Mak-Cas is $8,500. Again if you can find one. And a Takahashi Mewlon 10" Corrected Dal-Kirk is $9,700 new.
 
But after saying that an average sample of a  EdgeHD is going to be in the upper end of the decent to toward the top of the good range at a price that is far better inch for inch than a AP, TEC, or Tak! I think once you get things squared away on the 11" you will be very pleased. The best view I have ever had of M81 was in my 11" EdgeHD. It literally looked like a black and white version of the image on Wikipedia for M81.
 

Look into a Rayox saddle for your Mach1 by the way. It makes mounting SO much easier. I have one on my CGX and Mach1 since I use my 14" on both of them, Yes the Mach1 and CGX will support a 14" EdgeHD for visual and do it without breaking a sweat.


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#83 NMBob

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Posted 24 November 2018 - 09:04 PM

Geez! Well, you could just send it back, or enjoy one of those rare chances to pick the best one? On the other hand since you modded the 1st one I guess the 1st option is better. Amazing though, that they sent you some more stuff. 

I'm thinking 200x280mm binoculars. "You sent me another telescope? When?" :)

 

I'll have to get them on the line Monday morning and see what is going on. I don't think there's anything else wrong with this first one, and I don't want them stealing my secondary upgrade mod if I have to send it back. :)



#84 NMBob

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Posted 25 November 2018 - 01:20 AM

For crying out loud! No binoculars. The battery box is what came from Yorba Linda two days early. No where near 45lbs, though, but that's what the paperwork says. So no new scope.

 

This is a Powerwerx battery box with a 35Ah battery and a 20W solar panel with a Battery Tender controller for charging. Two Powerpole outlets, voltmeter, two 5V USB outlets, cigarette lighter outlet and direct connections to the battery. The Powerpoles are on without the voltmeter and 5V outlets being on. Had to lengthen one of the internal leads to the battery, but otherwise nice.

 

Played with the collimator all afternoon. Have to play some more. There seems to be a lot of ways to "fix" the results, but I'm not sure I was doing everything correctly. The instructions are slightly bad, and things in the them don't exactly match their videos.

 

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#85 starman876

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Posted 25 November 2018 - 09:42 PM

First, the EdgeHD 14's are the last Celestron scopes made in Torrance California. I know this for a fact because I have toured the factory and seen them being made. Sadly I wasn't able to take photos.
 
Second, the Edge series as a whole tend to be very well made scopes for a mass produced scope.  So the chances of getting a good one (at least diffraction limited) are very high. On the order of likely 90%+. 
 
Third, I have owned four EdgeHD scopes to date including the 14" I have now. They have all been diffraction limited. Including the 11".
 
Fourth, the TEMPest fans are an absolute must on them. In my experience it will cut cooling time by at least 40% if not 50% with the scope being usable to me for visual after 20 minutes on the 8", 30 minutes on the 11", and 45 minutes on the 14". By usable I mean stars that are somewhat small and not fuzzy flaring balls of light.
 
Fifth, when properly cooled and collimated a EdgeHD provides near APO refractor quality views to the edge of the field. 
 
Sixth, so many have problems with collimation and bothering to wait for the scope to properly cool which is where the majority of the bad reports come from. 
 
Seventh, those who change scopes like they change underwear are likely on a quest for unobtainium. There is no such thing as a perfect scope. There is bad, decent, good, and very good. Once you get into the very good range you are at the top of the heap. This is the area where Takahashi, Astro-Physics, and TEC are. But a 10" Astro-Physics Mak-Cass is $17,000+ USD *IF* you can find one. The current waiting list is getting notifications for the 1998-2000 year range. A TEC 10" Mak-Cas is $8,500. Again if you can find one. And a Takahashi Mewlon 10" Corrected Dal-Kirk is $9,700 new.
 
But after saying that an average sample of a  EdgeHD is going to be in the upper end of the decent to toward the top of the good range at a price that is far better inch for inch than a AP, TEC, or Tak! I think once you get things squared away on the 11" you will be very pleased. The best view I have ever had of M81 was in my 11" EdgeHD. It literally looked like a black and white version of the image on Wikipedia for M81.
 

Look into a Rayox saddle for your Mach1 by the way. It makes mounting SO much easier. I have one on my CGX and Mach1 since I use my 14" on both of them, Yes the Mach1 and CGX will support a 14" EdgeHD for visual and do it without breaking a sweat.

I think the ones that change scopes like people change underwear have no clue.  They most likely in their course of trying scopes have had some of the best scope available, but just do not hang on to them even when they say it is the best scope they have ever owned I think are crazy.   Why would anyone let the best scope go they have ever owned unless they have found something better.   I made that mistake once because I did not know any better. 


Edited by starman876, 25 November 2018 - 09:43 PM.


#86 BillP

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Posted 25 November 2018 - 10:21 PM

Ignore what you hear about the past from people who have no clue how to collimate an SCT.

 

waytogo.gif   I would say ignore all anecdotal meanderings by folks regarding quality variation on any branding of scope.  They simply do not have the data and are making nothing more than dataless guesses.  So in other words, all a bunch of hoo-haa.  Also amazing the number of folks who do not know how to collimate properly....and when they do collimate, they do it incorrectly (mostly not using sufficient magnification).  I've never purchased a scope, SCTs included, that was  optically poor.  Many did not show well, but after I collimated them then those "poor" ones became "excellent" ones lol.gif


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#87 Umasscrew39

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Posted 27 November 2018 - 06:17 AM

For crying out loud! No binoculars. The battery box is what came from Yorba Linda two days early. No where near 45lbs, though, but that's what the paperwork says. So no new scope.

 

This is a Powerwerx battery box with a 35Ah battery and a 20W solar panel with a Battery Tender controller for charging. Two Powerpole outlets, voltmeter, two 5V USB outlets, cigarette lighter outlet and direct connections to the battery. The Powerpoles are on without the voltmeter and 5V outlets being on. Had to lengthen one of the internal leads to the battery, but otherwise nice.

 

Played with the collimator all afternoon. Have to play some more. There seems to be a lot of ways to "fix" the results, but I'm not sure I was doing everything correctly. The instructions are slightly bad, and things in the them don't exactly match their videos.

Bob

 

I just received my Hotech (second hand) and the paper instructions are not well written (v9) and the procedure seems more complicated than I anticipated.  I saw a U-Tube video that might help me and I'll start playing with it today but the hardest part seems to get the OTA aligned squarely with the collimator screen.   I'm already a little confused as to how to use it with the C11" on a GEM.  The pictures are all on a fork mount.  Is your scope on a GEM?  I am assuming I can place the scope horizontally and just use DEC to move up and down.  Also, looks like I am missing the diffuser strips- hoping I can use tape instead or they seem to have a alternative procedure without using them. 

 

Any lessons learned as you use it would be appreciated.  If I can get this done correctly, then I'll deal with the hyperstar.

 

Bruce


Edited by Umasscrew39, 27 November 2018 - 12:18 PM.


#88 CHASLX200

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Posted 27 November 2018 - 06:30 AM

Being crazy could explain quite a bit around here. smile.gif

 

I haven't had any trouble with the Edge 8 I got last year, and it came via the same way from the same place. It gets dragged all over the countryside and I don't think I've ever even adjusted the collimation. !!!

 

Ordered the Hotech SCT collimator. Starizona had it for $399, instead of $455 everywhere else, but oddly they didn't even list the HyperStar add-on so you can collimate the HS lens with it. Funny. Got that from AgenaAstro. I could very well be dangerous by next weekend, or at least prepared to get that way, or prepared to box it all up and send it back. smile.gif

 

Being crazy could explain quite a bit around here. smile.gif

 

I haven't had any trouble with the Edge 8 I got last year, and it came via the same way from the same place. It gets dragged all over the countryside and I don't think I've ever even adjusted the collimation. !!!

 

Ordered the Hotech SCT collimator. Starizona had it for $399, instead of $455 everywhere else, but oddly they didn't even list the HyperStar add-on so you can collimate the HS lens with it. Funny. Got that from AgenaAstro. I could very well be dangerous by next weekend, or at least prepared to get that way, or prepared to box it all up and send it back. smile.gif

I have no problem collimating a SCT . I can even do in the dark if you get what i am saying.  Just start out with a lower power eyepiece and work up to higher powers to fine collimate. I just got another C8 and it is dead center and it just don't do it for me.  It was made around 2002.  If someone wants to DPAC it then come and do it.   This seems to be a hard subject for some people and i am just telling it the way i see it. 


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#89 starman876

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Posted 27 November 2018 - 08:26 AM

Bob

 

I just received my Hotech (second hand) and the paper instructions are not well written (v9) and the procedure seems more complicated than I anticipated.  I saw a U-Tube video that might help me and I'll start playing with it today but the hardest part seems to get the OTA aligned squarely with the collimator screen.   I'm already a little confused as to how to use it with the C11" on a GEM.  The pictures are all on a fork mount.  Is your scope on a GEM?  I am assuming I can place the scope horizontally and just use DEC to move up and down.  Also, looks like I am missing the diffuser strips- hoping I can use tape instead or they seem to have a alternative procedure without using them. 

 

Any lessons learned as you use it would be appreciated.  If I can get this correctly, then I'll deal with the hyperstar.

 

Bruce

Collimation is so critical.  All you need is  a hair off and all is lost.   


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#90 Umasscrew39

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Posted 27 November 2018 - 09:17 AM

Collimation is so critical.  All you need is  a hair off and all is lost.   

I completely agree.  That is exactly why I was never satisfied with the eyeball/donut method.  I did have better success with the GoldAstro mask but even with that seeing has to be ideal for it to be most effective.  I just moved cross-country and I took the C11" outside once and could tell immediately that it needs to be re-collimated.   And the sky in central FL have been horrible since moving here, thus the attempt to try and collimate with the Hotech collimator.  If I cannot get good results, I guess I will sell it and try the GoldAstro approach as soon as I get better weather.



#91 bobhen

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Posted 27 November 2018 - 11:14 AM

Everyone lists or blames collimation as a reason for soft SCT views. When in fact slight (read slight again) miss-collimation will not impact the sharpness of the view.

 

If collimation is off just a tad (say a Jupiter diameter) it will still be perfect somewhere in the field of view – just not in the center of the field. Just move the planet around to the spot where the scope is collimated – somewhere slightly off center. The scope will now give the best views it can. The best views will just be off center until you collimate the scope. Gross miss-collimation is another story but that is easily seen in the star test.

 

Bob



#92 starman876

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Posted 27 November 2018 - 11:36 AM

Everyone lists or blames collimation as a reason for soft SCT views. When in fact slight (read slight again) miss-collimation will not impact the sharpness of the view.

 

If collimation is off just a tad (say a Jupiter diameter) it will still be perfect somewhere in the field of view – just not in the center of the field. Just move the planet around to the spot where the scope is collimated – somewhere slightly off center. The scope will now give the best views it can. The best views will just be off center until you collimate the scope. Gross miss-collimation is another story but that is easily seen in the star test.

 

Bob

Where did this theory come from?


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#93 NMBob

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Posted 27 November 2018 - 12:03 PM

I've always just used the donut method too, but there's more to it. The secondary, while pointing the right direction, may not be in the middle of the corrector, or the corrector may not be in the middle of the scope. Then this HoTech setup also checks the alignment of an independent focuser that you may have on the back of the scope. However, it just kinda glosses over the main mirror shifting about.

 

On this C11 there is a dark grey washer between, I'm guessing, a big nut that holds the secondary mount in the center of the corrector and the corrector itself. It's not centered. There's a little bit more washer sticking out on one side than the other. I was thinking this collimator would tell me if the secondary mount is off-center or not. Maybe it did and I just missed it. The procedure for checking that is clearly shown in the videos and the HyperStar instructions, but not the regular instructions.

 

Bruce:

I was able to get the scope and the target aligned with each other after a bit. I have a bubble level on the scope saddle to get the tube level. I don't know if that helped or not. It looks like you can do it at any angle. They do make a big deal about getting that correct to start with. The funny thing was that when I switched to my Edge 8 at the very end of the day it all seemed to line up instantly. I just had to move the tripod for the target over a little bit, because the scope was a smaller diameter. There are about 12 things going on at a time, so it's tricky. Any movement of anything can throw all the rest off. Just get the initial cross pattern in the center. I had the scopes on my Mach1 mount with the RA rotated all the way over to one side. The rotation of the tube (like the "top" of the tube) doesn't have to physically be "up", so an EQ mount is OK. I'll probably use my Evolution mount for the Edge 8/HyperStar and the Super C8 that I want to check.

 

Oh, I have V8 of the instructions. They came with a new system. I'll see if I can get the newer ones. The diffuser strips look a lot like Scotch brand Magic Tape to me. They turn the four crosshair lines into a donut, so with or without them works. My instructions didn't say anything about the little target on the 1-1/4 or 2" mirror that you put on the back end, but they must be there for a reason.

 

Just go slow and get each step right before moving on. I played around a lot just to see what moving each thing would do to the patterns and then sitting for a second to make sure I understood what was going on. Those lasers are bouncing all over the place. I didn't get far enough to try the HyperStar stuff.

 

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#94 Umasscrew39

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Posted 27 November 2018 - 12:33 PM

This is very helpful- thanks much.

 

Version 8 came with my kit too.  I downloaded v9 from the internet which gives a bit more info in section 7 which was revised and a glossary of terms at the end.  Getting it online also has the advantage of much better pictures to see what should be done.



#95 NMBob

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Posted 27 November 2018 - 01:48 PM

Geeze, didn't even think about looking ONLINE for the manual. I was waiting for HoTech to get back to me. V9 is a lot bigger and it's in living color! :) I'll try to go through it tonight with my old C8. Thanks!



#96 WadeH237

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Posted 27 November 2018 - 01:54 PM

Where did this theory come from?

I believe that he is correct and I think that it's due to spherical primary and secondary mirrors.

 

Of all the scopes that I own, the SCTs are the easiest to collimate by far.  There are just 3 screws and you are only adjusting the tilt of the secondary.  On my Newtonians, I have to adjust the tilt of both the primary and secondary mirrors.

 

You may have read in this forum that RCs are difficult to collimate.  That's because they have no spherical optical elements.  Both mirrors are hyperbolic.  Tilt on both matters.  Lateral alignment between the primary and secondary mirrors matters.  Spacing between the primary and secondary mirrors matters.  RCs can be a real bear to deal with, especially if the mechanical quality is not up to par.



#97 starman876

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Posted 27 November 2018 - 03:10 PM

But the secondary is not spherical. It is hyperbolic. Therefore I am not sure I would agree with moving the image to another part of the optics would sharpen it up. There is more to collimating an SCT than just aligning the secondary.

#98 TG

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Posted 27 November 2018 - 03:26 PM

Bob

 

I just received my Hotech (second hand) and the paper instructions are not well written (v9) and the procedure seems more complicated than I anticipated.  I saw a U-Tube video that might help me and I'll start playing with it today but the hardest part seems to get the OTA aligned squarely with the collimator screen.   I'm already a little confused as to how to use it with the C11" on a GEM.  The pictures are all on a fork mount.  Is your scope on a GEM?  I am assuming I can place the scope horizontally and just use DEC to move up and down.  Also, looks like I am missing the diffuser strips- hoping I can use tape instead or they seem to have a alternative procedure without using them. 

 

Any lessons learned as you use it would be appreciated.  If I can get this done correctly, then I'll deal with the hyperstar.

 

Bruce

Bruce,

 

HoTech has two videos on Youtube that detail its use. Watch them multiple times and watch them closely.

 

For GEM mounts, use the mount's polar alignment adjustments. If you place the OTA horizontally, you need to use just the Az polar adjustment and the DEC axis can be used for up/down. However, I found that collimating a 14-inch scope horizontally resulted in it being miscollimated  when pointed up. So, I collimated it pointed up at 45° and the results were better. But when you point it up, you have to use both polar Az and Alt adjustments to 'co-align' it with the HoTech CTC but the movements will be non-orthogonal, i.e., adjusting each axis results in the cross moving both up/down and left/right, a bit like SCT collimation screws. But it's easy to learn how to make it go where you want.

 

Hope this helps,

Tanveer


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#99 WadeH237

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Posted 27 November 2018 - 03:48 PM

But the secondary is not spherical. It is hyperbolic. Therefore I am not sure I would agree with moving the image to another part of the optics would sharpen it up. There is more to collimating an SCT than just aligning the secondary.

A standard Schmidt-Cassegrain has both spherical primaries and spherical secondaries (I believe that's the whole reason for the corrector plate).  Look at figure 174 on this page.  I believe that this is true for all Celestron SCTs, and Meade non-ACF SCTs.

 

The Celestron EdgeHD scopes correct for coma (and flatness) with a corrector lens in the baffle tube.  I think that the Meade ACF scopes have an aspherical secondary mirror to correct for coma.  I used to own an 8" Meade ACF scope, and it was as easy to collimate as any other SCT that I've owned, so I don't know how non-spherical the secondaries on the ACFs, and how much it affects collimation.

 

I think that at some point in the past, Celestron did some touch-ups to the secondary mirrors, which made them sensitive to maintaining rotation orientation with the primary that it shipped with - but I don't think that's been true for a while.

 

You may be thinking of Classical Cassegrains, which do have hyperbolic secondary mirrors.



#100 starman876

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Posted 27 November 2018 - 04:23 PM

A standard Schmidt-Cassegrain has both spherical primaries and spherical secondaries (I believe that's the whole reason for the corrector plate).  Look at figure 174 on this page.  I believe that this is true for all Celestron SCTs, and Meade non-ACF SCTs.

 

The Celestron EdgeHD scopes correct for coma (and flatness) with a corrector lens in the baffle tube.  I think that the Meade ACF scopes have an aspherical secondary mirror to correct for coma.  I used to own an 8" Meade ACF scope, and it was as easy to collimate as any other SCT that I've owned, so I don't know how non-spherical the secondaries on the ACFs, and how much it affects collimation.

 

I think that at some point in the past, Celestron did some touch-ups to the secondary mirrors, which made them sensitive to maintaining rotation orientation with the primary that it shipped with - but I don't think that's been true for a while.

 

You may be thinking of Classical Cassegrains, which do have hyperbolic secondary mirrors.

you maybe correct in that I am thinking of classical cassegrains.  However the secondary in an SCT is Convex.


Edited by starman876, 27 November 2018 - 04:26 PM.



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