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

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#26 SandyHouTex

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Posted 31 October 2018 - 12:44 PM

The credit card has been cleared for takeoff and Celestron is having an Edge sale. Since the 70's I've wanted a C14, but I think it's time to start thinking C11, instead. At 28# it should *never* give me too much trouble -- should even be able to heft it up for the girly-mounting method in a few years -- and it will be well handled by my Mach1 mount. I have to drag everything around to set it up, so the 11 will be a plus there. Looking at the list in the sig this should be my last scope. Of course, that's what I said around scope number 5, but other than a huge Dob I just don't want any other scope. I don't need any other scope. I've got all of my bases covered and everything is working pretty well.

 

In reading through everything it seems like getting a good one or a bad one is a little more iffy with these eleven inchers. Maybe bad things just show up more readily. What do you think are the chances of getting a lemon? I sure wish their focuser was a bit better, but there you go. Been reading the threads about fixing that. I've been watching Celestron images shift for almost 40 years. smile.gif The locks do help on my 8 Edge, so I guess it's no big deal.

 

Thanks!

 

Bob

I'd say 95-5.  Celestron couldn't stay in business unless most of their scopes met the "diffraction limited" 1/4 wave criteria.  I have bought 9 in the last 8 years and I only had to send one back due to a thumb print on the front of the mirror.


Edited by SandyHouTex, 31 October 2018 - 12:45 PM.

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#27 Magnetic Field

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Posted 31 October 2018 - 01:58 PM

I'd say 95-5.  Celestron couldn't stay in business unless most of their scopes met the "diffraction limited" 1/4 wave criteria.  I have bought 9 in the last 8 years and I only had to send one back due to a thumb print on the front of the mirror.

 

If we had proper astronomy amateur magazines they would buy (anonymously) telescopes and perform optical bench tests and would print the results. I understand they couldbn't test every telescope ever produced. However, they could test the mainstream ones (e.g. SCT from Meade or Celestron, Maksutovs from Sky-Watcher, ED refractors from Orion etc.)

 

German bicycling magazines still do it (frame tests, stiffness tests, faitigue stress tests etc) often in collaboration with universities.


Edited by Magnetic Field, 31 October 2018 - 02:00 PM.

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#28 Axunator

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Posted 31 October 2018 - 02:16 PM

If we had proper astronomy amateur magazines they would buy (anonymously) telescopes and perform optical bench tests and would print the results. 

I agree that most "tests" in the two biggest American magazines are hardly ever truly critical and IMO read more like advertisements, but one of the biggest problems in conducting really rigorous testing of mass-produced, affordable scopes is the rather large variability in their optical quality. So the results would only apply to that particular specimen being tested - the one you might end up buying could be from the opposite end of the Gaussian curve...

 

This becomes quickly evident if you study any of the websites that have large databases of test results (by mostly European labs) for amateur telescopes.


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#29 Magnetic Field

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Posted 31 October 2018 - 02:32 PM

I agree that most "tests" in the two biggest American magazines are hardly ever truly critical and IMO read more like advertisements, but one of the biggest problems in conducting really rigorous testing of mass-produced, affordable scopes is the rather large variability in their optical quality. So the results would only apply to that particular specimen being tested - the one you might end up buying could be from the opposite end of the Gaussian curve...

 

This becomes quickly evident if you study any of the websites that have large databases of test results (by mostly European labs) for amateur telescopes.

I don't like reading Rohr (the German tester).

 

Maybe it is just me but I don't like his condescending high-nosed writing and judgemental style (I am able to read German because it is my mother tongue). The guy is testing telescopes and nothing more or less and not building space ships.



#30 NMBob

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Posted 31 October 2018 - 02:44 PM

I'd say 95-5.  Celestron couldn't stay in business unless most of their scopes met the "diffraction limited" 1/4 wave criteria.  I have bought 9 in the last 8 years and I only had to send one back due to a thumb print on the front of the mirror.

I know you are not supposed to ever shine a flashlight down the tube, but you would think that last inspector at the factory would do it. :)


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#31 Magnetic Field

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Posted 31 October 2018 - 02:49 PM

I know you are not supposed to ever shine a flashlight down the tube, but you would think that last inspector at the factory would do it. smile.gif

 

In a perfect world we would have two things less to bother with:

 

a) Every reflector type and catadioptric telescope out there has got the optical and mechanical quality of a Questar at the price of a Celestron.

 

b) Every refractor out there has  got zero chromatic aberration at the price of a Meade.


Edited by Magnetic Field, 31 October 2018 - 02:49 PM.

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#32 Axunator

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Posted 31 October 2018 - 04:47 PM

I don't like reading Rohr (the German tester).

Maybe it is just me but I don't like his condescending high-nosed writing and judgemental style (I am able to read German because it is my mother tongue). The guy is testing telescopes and nothing more or less and not building space ships.


There are several other sites (still mostly European) as well, many with more ’neutral’ tone. I’m on my iPhone now so too difficult to paste links.

And whether you like Rohr’s writing style or not doesn’t change the fact that n=1 sample of any mass-produced consumer telescope does not tell much about the optical quality of the product line as a whole.
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#33 Procyon

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Posted 31 October 2018 - 05:09 PM

I heard that Company Seven tests all their celestrons before they ship them to customers. If I was buy new I would give them a call first.

Company Seven is a resource for the international amateur and professional astronomy community, and a registered U.S. Department of Defense contractor.

http://www.company7.com/

When I sold my astro-physics F9 180 EDT they acted as the intermediary.

This is what I was thinking too. I sent them an email earlier this year about if they actually inspected these diagonals I was looking for and boy there reply email knocked my socks off. I was like, dang these guys take their stuff n clients serious. It was a bit too scientific but I'll definitely take it over zero replies lol. It says on their website they inspect their scopes etc, so that's always good too...

I bought a new C6, can't remember from where, optics were great, sold it and bought a used Edge 8, never really liked it for some reason so I sold it, bought a 6 month old CPC 1100 from someone who bought it from Highpoint Scientific which also state they check their scopes before selling them, does that mean the mirror too, I don't know, all I know is this XLT just shows amazing views of any object I point too so It's a keeper to me. Good luck hope you get a great one.

Edited by Procyon, 01 November 2018 - 04:04 AM.

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#34 glmorri

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Posted 01 November 2018 - 12:22 AM

Here’s a post that talks about the chances of a decent C11:

 

https://www.cloudyni...a-c11s-and-c8s/


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#35 Peter Besenbruch

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Posted 01 November 2018 - 02:11 AM

Yeah, when something goes wrong I come here to post. When everything is going well I'm too busy having fun to post. smile.gif

It's time to change that. If you like the new scope, we want to hear about it.


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#36 CHASLX200

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Posted 01 November 2018 - 05:13 AM

It's time to change that. If you like the new scope, we want to hear about it.

There are one or two here that want to make you think all SCT's are perfect and get their feelings hurt if someone speaks the truth.



#37 NMBob

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Posted 01 November 2018 - 08:37 AM

Here’s a post that talks about the chances of a decent C11:

 

https://www.cloudyni...a-c11s-and-c8s/

Thanks! I forgot all about that thread. I'm not sure what I was searching for, but that one never came up. Looks like I just have to be careful WHO tested it to get a good one. :)



#38 rmollise

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Posted 01 November 2018 - 08:42 AM

The credit card has been cleared for takeoff and Celestron is having an Edge sale. Since the 70's I've wanted a C14, but I think it's time to start thinking C11, instead. At 28# it should *never* give me too much trouble -- should even be able to heft it up for the girly-mounting method in a few years -- and it will be well handled by my Mach1 mount. I have to drag everything around to set it up, so the 11 will be a plus there. Looking at the list in the sig this should be my last scope. Of course, that's what I said around scope number 5, but other than a huge Dob I just don't want any other scope. I don't need any other scope. I've got all of my bases covered and everything is working pretty well.

 

In reading through everything it seems like getting a good one or a bad one is a little more iffy with these eleven inchers. Maybe bad things just show up more readily. What do you think are the chances of getting a lemon? I sure wish their focuser was a bit better, but there you go. Been reading the threads about fixing that. I've been watching Celestron images shift for almost 40 years. smile.gif The locks do help on my 8 Edge, so I guess it's no big deal.

 

Thanks!

 

Bob

 

Celestron is actually quite consistent optically (so is Meade). Will you get a telescope that is the optical equivalent of a Takahashi? Probably not, but you will get at least a diffraction limited telescope, which is more than good enough for most people. In fact, given the seeing most have most of the year, you will be unlikely to notice much/any difference. If you want "perfect" (or at least close), be prepared to pay for it. ;)


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#39 treadmarks

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Posted 01 November 2018 - 09:31 AM

My concern with the C11 is not so much the optics but the cooling situation. Even the non-Edge C14's have vents, but to get that with the C11 you need to go EdgeHD. At this size and a sealed tube, it seems to me cooling could be a major problem. I wonder what everyone's experiences are with this. The idea of insulation looks like it could be the plain old C11's savior.



#40 NMBob

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Posted 01 November 2018 - 09:59 AM

Celestron is actually quite consistent optically (so is Meade). Will you get a telescope that is the optical equivalent of a Takahashi? Probably not, but you will get at least a diffraction limited telescope, which is more than good enough for most people. In fact, given the seeing most have most of the year, you will be unlikely to notice much/any difference. If you want "perfect" (or at least close), be prepared to pay for it. wink.gif

That's what I figure. As long as I can't tell how bad it is I'll be good. :) And yeah, the seeing has only been good enough for full-on C8 work for parts of a few nights this year. I don't know anyone around here that has a C11 to put it next to. I'll just have to plop it down next to my Edge 8. The college observatory here has three C14s, but they have cameras that are probably, by now, permanently rusted to the backs of them.



#41 Procyon

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Posted 01 November 2018 - 10:09 AM

My concern with the C11 is not so much the optics but the cooling situation. Even the non-Edge C14's have vents, but to get that with the C11 you need to go EdgeHD. At this size and a sealed tube, it seems to me cooling could be a major problem. I wonder what everyone's experiences are with this. The idea of insulation looks like it could be the plain old C11's savior.

The simple but slow way: (This is how I do it since I'm never in any rush): You take it out, place it somewhere and come back in 2 hours. That's it lol. Don't forget the dew shield, dew strap etc.

On average I'd say it takes a good hour to an hour and a half to acclimate, faster with a Lymax Cooler or Edge Add On Fans for Edges. Between 12am and 5am is where the views are always crisp and magnificent for me. I will add a Lymax Cooler sometime soon, it's pretty much the only accessory I'm missing now.

I think you'll be very happy with a C11, the difference for me between it and a previous Edge 8 was HUGE. Much bigger than the difference between a 6 and 8" SCT. It's much better than my first 10" dob too, on planets and dso's.

Edited by Procyon, 01 November 2018 - 10:28 AM.

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#42 NMBob

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Posted 01 November 2018 - 10:09 AM

My concern with the C11 is not so much the optics but the cooling situation. Even the non-Edge C14's have vents, but to get that with the C11 you need to go EdgeHD. At this size and a sealed tube, it seems to me cooling could be a major problem. I wonder what everyone's experiences are with this. The idea of insulation looks like it could be the plain old C11's savior.

I have the TEPM-est fans on the C8 and things to seem to improve/change quickly when I start observing and then turn them on. I usually get them going while I'm setting things up and usually I notice more turbulence from the ground heat. I guess the new fans (mine) for the C8s move less air than the older models. To look at them they are mostly motor with very small blades. Deep Space Products said they couldn't get the older fans anymore. They still seem to do something.

 

I have a set coming for the C11. They are larger, so move more air.


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#43 NMBob

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Posted 01 November 2018 - 10:34 AM

The simple but slow way: (This is how I do it since I'm never in any rush): You take it out, place it somewhere and come back in 2 hours. That's it lol. Don't forget the dew shield, dew strap etc.

 

On average I'd say it takes a good hour to an hour and a half to acclimate, faster with a Lymax Cooler or Edge Add On Fans for Edges. Between 12am and 5am is where the views are always crisp and magnificent for me. I will add a Lymax Cooler sometime soon, it's pretty much the only accessory I'm missing now. 

 

I think you will be very happy with a C11, the difference for me between it and a previous Edge 8 was HUGE. Much bigger than the difference between a 6 and 8" SCT. It's much better than my first 10" dob too, on planets and dso's. 

I have to pack everything up...usually go to storage, get some of it, pack it in the pickup...then ride off into the sunset to set things up, so I never get to let the scopes sit out for a couple of hours. However, I am able to just 'let them be' at our yearly 5-day star party and it does work well.

 

Good to hear, because I keep staring at a ruler and thinking, huh, that's not that much bigger (8 to 11), 14 would have been better and it's even bigger than the ruler! :)


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#44 Procyon

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Posted 01 November 2018 - 10:42 AM

I have to pack everything up...usually go to storage, get some of it, pack it in the pickup...then ride off into the sunset to set things up, so I never get to let the scopes sit out for a couple of hours. However, I am able to just 'let them be' at our yearly 5-day star party and it does work well.

 

Good to hear, because I keep staring at a ruler and thinking, huh, that's not that much bigger (8 to 11), 14 would have been better and it's even bigger than the ruler! smile.gif

When I drive to a dark site, I just leave the wndows down a bit, it really helps. By the time I reach there it's ready to go.


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#45 NMBob

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Posted 01 November 2018 - 11:53 AM

When I drive to a dark site, I just leave the wndows down a bit, it really helps. By the time I reach there it's ready to go.

It's only a 20min ride for me, and most of that is stop signs. :) An hour for really dark, but there's nothing but country between here and there, so there's even closer places.


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#46 treadmarks

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Posted 01 November 2018 - 12:33 PM

The simple but slow way: (This is how I do it since I'm never in any rush): You take it out, place it somewhere and come back in 2 hours. That's it lol. Don't forget the dew shield, dew strap etc.

On average I'd say it takes a good hour to an hour and a half to acclimate, faster with a Lymax Cooler or Edge Add On Fans for Edges. Between 12am and 5am is where the views are always crisp and magnificent for me. I will add a Lymax Cooler sometime soon, it's pretty much the only accessory I'm missing now.

I think you'll be very happy with a C11, the difference for me between it and a previous Edge 8 was HUGE. Much bigger than the difference between a 6 and 8" SCT. It's much better than my first 10" dob too, on planets and dso's.

 

When I drive to a dark site, I just leave the wndows down a bit, it really helps. By the time I reach there it's ready to go.

This is pretty much exactly what I already do with my C8. I cool it at home first, then I'm concerned it could actually warm up in the car on the way to the dark site, so I leave the heat off and crack the windows or turn the fans on. Never had a problem.

 

Anyway since you're in Canada, if the C11 can work for you, it can work for anybody. I think if ever I were to go up in aperture, the C11 is at the top of my list right now, followed by a 12" push-to Dob. It would probably be years before that happens though, if ever. I've barely even gotten started with my C8.


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#47 Bean614

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Posted 01 November 2018 - 06:17 PM

You all were no help at all. It's ordered. smile.gif
TEMP-est fans ordered.
Orange ADM Vixen bar for the top ordered.
Camera adapter ordered.
Celestron Nexstar case ordered. I have one of these for my 8". I like them, except the interior pocket thing isn't great.

Will have to wait on the HyperStar.

 

The scope size does seem right, and I guess I'll take a shot. I bet it will turn out fine.

 

Thanks!

Before trying to install those Tempest fans, and while you can still return them, go to your local hardware store and spend $22 on a roll of Reflectix.  Wrap your scope BEFORE you take it outside.  Then, take it out whenever you please, and start observing immediately (!), with no thermal acclimation worries.  You'll thank us later.



#48 Procyon

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Posted 01 November 2018 - 09:43 PM

Some interesting reads.

http://www.company7....tron/index.html

http://www.company7.com/testing.html

Edited by Procyon, 01 November 2018 - 09:45 PM.

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#49 rolo

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Posted 01 November 2018 - 10:11 PM

Your chances are very good that you'll get a good one....waytogo.gif



#50 NMBob

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Posted 02 November 2018 - 08:30 AM

Your chances are very good that you'll get a good one....waytogo.gif

Arrival went from Wednesday to Tuesday to now Monday. It must be a good omen. :)

 

I'll get the Celestron box/rolling case today. ADM V-bar for the top tomorrow...

 

I had read the Company 7 page on the history before. Very interesting,

 

Having worked for years in a fairly thermodynamic place (nuclear power plant) I'm not going to go down the Reflectix pathway just yet. I'll keep reading. :)

 

Bob




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