Why did you buy an SCT?!

[newbie alert]

That's easy, they're so versatile...

[beka]

I was just wondering about the "mushiness" of SCT views as compared to Newtonians. Is there any comparision of the views between that of an SCT and a non-premium Newtonian of similar aperture, but say with the Newtonian "barlowed" up to the same f-ratio as the SCT? While I have not had the opportunity to look through a large dob, faint stars throught my CPC 1100 seem to be really pinpoint (for example in open clusters like M37).

Best

[Davesellars]

I think that perhaps the mushiness can be contributed somewhat to lack of stabilisation to ambient temperature.  When I had my C8 it would take generally 2 hours (and I used to store in an unheated shed sometimes) for stars to appear anything like pin-point.  The scope was very well collimated however the inevitable mirror flop would cause issues.  Once I moved up to the 12" dob, pin-point(ish) stars would would be much quicker to obtain.  IMHO, the SCT design was not suitable for quick sessions requiring far too much cool-down period (if it ever reached it...).

I bought the 8" SCT initially was because it touted to be good for everything and also because of its portability (I used to keep the EQ5 mount permanently in the shed) and back in 2014 the price was not too bad at £700.  It was very good for DSOs especially with the use of the focal reducer.  After a couple of years of intensive DSO hunting with it I felt I'd reached a limit with the aperture and thus sold it for the 12" dob.  For lunar observing it was very good however I was never that convinced with planetary observation (particularly Jupiter) with it - I felt it lacked real contrast and the planet was either too bright or if you dimmed it sufficiently with power then details were lost.  I never felt that it produced a really sharp image for planetary observation either (probably due to trying to the tube to ambient temperature which was constantly fluctuating.

[yuklop]

Agree with the above.

I had a LX200 12'' for quite a while, and had a lot of fun with it. Cooldown took ages though, even when stored in an unheated garage. At least 90 mins. Which meant most of the time I was using the thing unstabilised. I also felt I spent half the time collimating, and the other half wondering if the collimation was out. In truth, I was probably trying to collimate before the scope was properly cooled. But kids, work, and weather conspire to keep my observing between about 20:00 and 22:30. Barely enough time to cool it down.

Sold it a while back. Do I miss it? Not really. I think the scope was a lot better than my skills, and at a different stage of my observing life, I'm sure we'd have gotten on a lot better. Would like to try a C9.25 one day. Would also like a decent refractor one day. But that's for the future. I'm presently messing around with a classical cass and a DK that I somehow ended up acquiring with more-or-less wise auction site bidding. First impressions are that they are sharper than the SCT, and easier to collimate, but they are also both open tube, and so cooldown is quick.

[SthBohemia]

I suspect many of the negative comments are due to poor COLLIMATION, SCT's are notorious for falling out of collimation if stared at 2 long! Like all (or most) other scopes, quality can vary greatly. A Celestron made when Tasco took over the company is in all probability BAD! Whereas one made prior to  the Halleys comet event has a high probability of being well manufactured. Meades are relatively more consistent (quality wise) especially the ones made within USA...

[Zeta Reticulan]

39 minutes ago, SthBohemia said:

A Celestron made when Tasco took over the company is in all probability BAD! 

Why? Didn't Synta actually supply parts for Celestron when Johnson still owned it? From what I've read he always rated them highly. Although they're a Taiwanese/Canadian company (Synta Technology Corporation of Taiwan) the telescopes are actually constructed at a state of the art plant on the Chinese mainland (Suzhou Synta Optical Technology Co., Ltd). I certainly don't think my 9.25" Evolution is bad. It might not have the best optics compared to some SCT's but I thought it was pretty decent for a 235mm scope costing 2 grand. 

Edited August 20, 2022 by Zeta Reticulan
bad syntax

[DaveS]

I didn't, and am much happier as a result.

[SthBohemia]

5 minutes ago, Zeta Reticulan said:

Why? Didn't Synta actually supply parts for Celestron when Johnson still owned it?

http://www.company7.com/celestron/index.html

Read through 'dat'.... ^^

[Zeta Reticulan]

4 minutes ago, SthBohemia said:

http://www.company7.com/celestron/index.html

Read through 'dat'.... ^^

I think I've seen it before. I'm not sure of its accuracy. Doesn't answer my question though. 

Edited August 20, 2022 by Zeta Reticulan

[SthBohemia]

2 minutes ago, Zeta Reticulan said:

I think I've seen it before. Doesn't answer my question though. 

Hard to answer as who knows what goes on within the Asian underground factories! Bottom line being, when Tasco tookover Celestron the quality of Celestron optics hit rock bottom.. Why?? shrugs...

[Zeta Reticulan]

14 minutes ago, SthBohemia said:

Hard to answer as who knows what goes on within the Asian underground factories! Bottom line being, when Tasco tookover Celestron the quality of Celestron optics hit rock bottom.. Why?? shrugs...

Tasco have never actually been a manufacturer though, as far as I know. The Synta Technology Corporation and Suzhou Synta Optical Technology are not entirely the same. They have a business arrangement. I assume that due to the fact that the Chinese government often subsidises mainland manufacturing it is an economic agreement between the Taiwanese company and the Chinese registered company Suzhou Synta. 

[SthBohemia]

@Zeta Reticulan this opens up a 'can of worms' regarding Chinese vs European/USA manufactured goods. In honesty what would you prefer, a Leica-Zeiss camera or brand 'xxx' from China? A Questar Mak or a SW Mak? An Astro-Physics, Losmandy etc mount or brand 'XYZ'?

Sure, the Chinese manufactured goods are 'acceptable' but.....

Within Buy/Sell Dave offers a Fullerscope IV mount in exchange for a 'goto'. If I were within UK the SW HEQ6P would have been delivered to him pronto 🙂 

Many years ago purchased a used 10' Meade from USA (USA made), the seller upgraded to the 12" model (Chinese manufactured) he regretted the upgrade immediately and wished to hell he had kept the USA model. Clouded Knights contains many similar sorties....

[Mr Spock]

1 hour ago, SthBohemia said:

SCT's are notorious for falling out of collimation if stared at 2 long!

Completely untrue. My C9.25 would hold collimation almost indefinitely. 

All I'm seeing in this thread are a lot of assumptions made without any real evidence, and a lot of unfounded negativity towards some manufacturers. Perhaps the thread should get back on track.

[SthBohemia]

1 minute ago, Mr Spock said:

Completely untrue. My C9.25 would hold collimation almost indefinitely. 

Either you treat the scope gently or you have a very good SCT 🙂 Maybe I should refrain from the occasional kicks to SCT's and not drop them onto mounts! I have never had one that retains collimation well...

[Zeta Reticulan]

25 minutes ago, SthBohemia said:

@Zeta Reticulan this opens up a 'can of worms' regarding Chinese vs European/USA manufactured goods. In honesty what would you prefer, a Leica-Zeiss camera or brand 'xxx' from China? A Questar Mak or a SW Mak? An Astro-Physics, Losmandy etc mount or brand 'XYZ'?

Sure, the Chinese manufactured goods are 'acceptable' but.....

Within Buy/Sell Dave offers a Fullerscope IV mount in exchange for a 'goto'. If I were within UK the SW HEQ6P would have been delivered to him pronto 🙂 

Many years ago purchased a used 10' Meade from USA (USA made), the seller upgraded to the 12" model (Chinese manufactured) he regretted the upgrade immediately and wished to hell he had kept the USA model. Clouded Knights contains many similar sorties....

I'm with Spock on this. Let's not make generalisations about Asian manufacturing capabilities.

Edited August 20, 2022 by Zeta Reticulan

[SthBohemia]

3 minutes ago, Zeta Reticulan said:

I'm with Spock on this.

@Zeta Reticulan @Mr Spock Understand that any/all of my opinions are PURELY subjective gained over time, from 60 years ago when I first made a 6" scope and equatorial mount! Proof? Maybe proof of the pudding is in the eating? 🙂 

[Zeta Reticulan]

9 minutes ago, SthBohemia said:

@Zeta Reticulan @Mr Spock Understand that any/all of my opinions are PURELY subjective gained over time, from 60 years ago when I first made a 6" scope and equatorial mount! Proof? Maybe proof of the pudding is in the eating? 🙂 

Erm ... I'm not sure what you mean. Everything's a bit subjective. I'm not sure how that corresponds to Chinese made SCT's.

[inFINNity Deck]

I would not say that they all suffer from flaws like mirror-flop, as I heard other C11s perform better (I have no proof of that though), but the two I own both show this issue. I tested them in front of a collimator, which to me is sufficient proof (they both loose collimation when rotated along the optical axis by 180 degrees). Celestron did not want to answer my question of how much mirror-flop was allowed, only gave a figure for mirror-shift (which they both passed). Nor did they manage to repair the mirror-flop in the C11 EdgeHD I sent back to the States. Still I am using this scope as I do think it is a good performer once properly collimated (which needs to be repeated after a meridian-flip).

Nicolàs

[Highburymark]

The most frustrating thing about SCTs, in my experience at least, is that a small minority of examples produce stunning views. If you are fortunate to own one, you have close to the ideal telescope. But a great many more do not. An average SCT does most things reasonably well, but I ultimately found them disappointing when I wanted to push them hard. As a lunar/planetary scope, I’d take a 4-5” apo over an average C8 any day. 
BUT - there are some superb SCTs out there. Just a case of finding them.

[russ]

57 minutes ago, Mr Spock said:

Completely untrue. My C9.25 would hold collimation almost indefinitely. 

All I'm seeing in this thread are a lot of assumptions made without any real evidence, and a lot of unfounded negativity towards some manufacturers. Perhaps the thread should get back on track.

I agree. I have a C6 and C8, both hold collimation incredibly well. Where as my newt needs a tweak more often. 

Getting back on track. I have SCT's as the newt is a massive pain to use on an EQ and I seriously have to be in the right mood for it. The refractor I love but it's aperture challenged. And while it's lunar, planetary and double star prowess are great, it deep sky much less so. The SCT is a dream to use, collects enough light for deep sky and does well on the other stuff too. 

It's not all roses though. Cool down is a nightmare and dew an even bigger one. A dew shield doesn't work, active dew control is a must. The refractor I throw on the mount, give it 30mins and it's good to go. And while it will eventually dew over, I am usually done by then anyway.

No scope is perfect, SCT has its place.

 

[Highburymark]

20 minutes ago, russ said:

I agree. I have a C6 and C8, both hold collimation incredibly well. Where as my newt needs a tweak more often. 

Getting back on track. I have SCT's as the newt is a massive pain to use on an EQ and I seriously have to be in the right mood for it. The refractor I love but it's aperture challenged. And while it's lunar, planetary and double star prowess are great, it deep sky much less so. The SCT is a dream to use, collects enough light for deep sky and does well on the other stuff too. 

It's not all roses though. Cool down is a nightmare and dew an even bigger one. A dew shield doesn't work, active dew control is a must. The refractor I throw on the mount, give it 30mins and it's good to go. And while it will eventually dew over, I am usually done by then anyway.

No scope is perfect, SCT has its place.

 

Well said. And I agree about collimation. It was not a problem on my C6 or C8 Edge.

[fozzybear]

My Celestron C5 circa 90's gets loads of abuse and no probs with it and original coll screws just works 

[Elp]

To answer the title, because I always wanted one.

Edited August 20, 2022 by Elp

[fozzybear]

2 minutes ago, Elp said:

To answer the title, because I always wanted one.

You will be surprised great piece of kit 

[fozzybear]

Don't ask me why but my C5 is first out maybe because it is light and on a tripod for a quick survey then bring out the other siblings if the weather plays ball