Jump to content


Photo

I question the longevity of the modern SCT's

  • Please log in to reply
77 replies to this topic

#51 rmollise

rmollise

    Hubble

  • *****
  • Posts: 15469
  • Joined: 06 Jul 2007

Posted 22 January 2014 - 09:40 AM

I'm routinely surprised at the number of older scopes that are still going strong - the LX-5s and 6s, for example. It all comes down to the quality of the mount and components, and I'm afraid that some of the newer stuff just doesn't have the same quality. Some of the problem is that they aren't "overengineered" like the older scopes


That is somewhat true...but actually the opposite is often the case. Over the years, especially with go-to telescopes, manufacturers have learned to simplify cirucuit boards. That often results in far greater reliability, and is why later LX200 classics tend to be more reliable.

Actually, when it comes to electronics, if a PCB survives its first power up and the first 8-hours of life, it will last a long, long time. Maybe until the user does something stupid with it. :lol:

#52 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 43586
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 22 January 2014 - 09:45 AM


I think the modern alt-az GOTO mount really made the SCT viable because it made the viewing experience so much more comfortable. If I were to purchase another SCT.. it would be on an ALT-AZ mount..

Jon


Or a nice GEM, which can give you similar ergonomic benefits.

The things the equatorial fork had going for it back in the day were compactness & tracking.


Given the choice between a GEM and a Fork on a Wedge, there is no doubt the GEM is the way to go. My last 8 inch SCT rode on a CG-5 ASGT. The tube rotation and some of the positions can be awkward but stable, solid and generally comfortable...

Jon

#53 jaymcgil19

jaymcgil19

    Vendor-LX200 CLASSIC ELECTRONICS EXCHANGE

  • *****
  • Vendors
  • Posts: 58
  • Joined: 01 Apr 2013
  • Loc: S/E Michigan

Posted 22 January 2014 - 10:57 AM

That is somewhat true...but actually the opposite is often the case. Over the years, especially with go-to telescopes, manufacturers have learned to simplify cirucuit boards. That often results in far greater reliability, and is why later LX200 classics tend to be more reliable.

Actually, when it comes to electronics, if a PCB survives its first power up and the first 8-hours of life, it will last a long, long time. Maybe until the user does something stupid with it. :lol:


I was just looking at the specs on this capacitor

http://uk.rs-online....citors/2286874/

and it actually list 2000 hours as its life, kind of like a light bulb.

#54 rmollise

rmollise

    Hubble

  • *****
  • Posts: 15469
  • Joined: 06 Jul 2007

Posted 22 January 2014 - 11:08 AM


Given the choice between a GEM and a Fork on a Wedge, there is no doubt the GEM is the way to go. My last 8 inch SCT rode on a CG-5 ASGT. The tube rotation and some of the positions can be awkward but stable, solid and generally comfortable...

Jon


No doubt about that. I came to hate wedges some years ago. :lol:

OTOH, NOTHING is more comfortable for visual use than an alt-az mode fork mount SCT.

#55 rmollise

rmollise

    Hubble

  • *****
  • Posts: 15469
  • Joined: 06 Jul 2007

Posted 22 January 2014 - 11:09 AM


I was just looking at the specs on this capacitor

http://uk.rs-online....citors/2286874/

and it actually list 2000 hours as its life, kind of like a light bulb.


2000 hours is a lot of telescope time, and in reality, most capacitors will far, far exceed that. ;)

#56 Greg Boynton

Greg Boynton

    Explorer 1

  • -----
  • Posts: 97
  • Joined: 29 May 2009

Posted 22 January 2014 - 12:23 PM

Yes, there is a lot more to capacitor life than that 2000 hour spec. Things like ripple load, peak voltage and operating temp have a huge impact. In a properly engineered circuit normal aluminum electrolytics will last a heck of a long time. I've seen parts from the 1960's with untold hours on them that don't leak and still have acceptable ESR values.

What is a lot more likely, is a bad batch of components or an assembly error. As pointed our, you usually know about that in the first few hours.

#57 David Pavlich

David Pavlich

    Transmographied

  • *****
  • Administrators
  • Posts: 27312
  • Joined: 18 May 2005
  • Loc: Mandeville, LA USA

Posted 22 January 2014 - 01:05 PM


I think the modern alt-az GOTO mount really made the SCT viable because it made the viewing experience so much more comfortable. If I were to purchase another SCT.. it would be on an ALT-AZ mount..

Jon


Or a nice GEM, which can give you similar ergonomic benefits.

The things the equatorial fork had going for it back in the day were compactness & tracking.


Given the choice between a GEM and a Fork on a Wedge, there is no doubt the GEM is the way to go. My last 8 inch SCT rode on a CG-5 ASGT. The tube rotation and some of the positions can be awkward but stable, solid and generally comfortable...

Jon


About the only advantage to a wedge mounted SC would be for imaging...no meridian flip. Other than that, the GEM is superior.

David

#58 drollere

drollere

    Surveyor 1

  • *****
  • Posts: 1577
  • Joined: 02 Feb 2010
  • Loc: sebastopol, california

Posted 22 January 2014 - 01:18 PM

Can you give examples of Meade and Celestron SCT drives where plastic gears are failing?


can you give examples of meade or celestron drives with plastic gears, period? i don't service telescopes but i've serviced my LX200 and the drive mechanism is metal.

the OP is launched on implausibilities. first, that all SCTs are made with plastic gears; second, that enough SCT purchasers use them frequently enough for that to create a problem. there are price points where plastic gears may be used, but they will not be high end instruments, e.g. for astrophotographers.

manufacturers do not design for eternal use by immortal owners but for typical use by typical owners. the typical owner buys a scope, uses it for many nights, then once a month for a while, then puts it in the garage.

yes, electronics do fail, but i don't see that as a problem reported to any significant frequency either here or in the scope forums that i subscribe to.

#59 Gil V

Gil V

    Viking 1

  • -----
  • Posts: 629
  • Joined: 09 Sep 2012

Posted 22 January 2014 - 02:24 PM

Normally I agree with Rod (except when he discusses my former employer LOL).

I find a SCT on an equatorially mounted fork to be much more comfortable to use than when mounted alt-az. Easy to see the whole sky from a single standing observing position.

#60 amicus sidera

amicus sidera

    Skylab

  • *****
  • Posts: 4047
  • Joined: 14 Oct 2011
  • Loc: East of the Sun, West of the Moon...

Posted 22 January 2014 - 02:51 PM

Although optically today's SCT is just as good (if not slightly better) than those available 15 to 20 years ago, I feel everything else that comes with these scopes is cheap and poorly constructed. I'm talking about the mounts, internal gears and motors, and the computer boards that control the GoTo functionality. I will clarify...


I agree; there is a certain solidness missing from recent incarnations of the SCT, and not just from the use of plastics where metal once was. Designs now are made using CAD, which in my experience usually means that just enough material will be used to accomplish the task at hand, with little consideration given to the overall "feel" of a part. A little over-engineering is a good thing with a delicate instrument meant to be portable...


I own a circa 1989 Meade LX5. It's a non GoTo fork mounted unit. This scope functions flawlessly. Once polar aligned it tracks its target well. The optics are just as good as a new 8" SCT. I have talked to other owners of these old Meade's as well as older Celestron's and everyone is happy with the performance and ruggedness of their scopes.


Ditto. These model Meade scopes, along with older Celestron SCT's, are still very much in evidence among the groups I observe with. They are indeed well-liked, rugged and dependable.


The newer 8" SCT's like the CPC 8" are quite enticing. They are packed with features like GoTo drives with giant databases, and GPS self alignment, but they have plastic gears, computer boards that burn out within 5 years, and weaker tripods than their older siblings.
I've talked to several owners of late model Meade and Celestron products that have had issues with these components.


As have I; slicker and cheaper seems to be the order of he day.


Am I the only one who sees this as a longevity problem? Are we just entering an age of disposable scopes? If someone is spending over $1000 on a telescope shouldn't it ought to work for a while?


You are most assuredly not the only one noticing these issues, and how they relate to a given scope's longevity; such is a matter for discussion quite often among my friends and astronomical acquaintances, particularly when someone's whiz-bang go-to scope has entered into a coma (often an irreversible one, to boot - that's what happens when you can't obtain parts any longer). While its true that the OTA could be salvaged and placed on a GE mount, the SCT then loses its overall elegance, of which the fork mount is a considerable part.



#61 Chuck Hards

Chuck Hards

    Fly Me to the Moon

  • *****
  • Moderators
  • Posts: 5360
  • Joined: 03 May 2010
  • Loc: The Great Basin

Posted 22 January 2014 - 02:52 PM

NOTHING is more comfortable for visual use than an alt-az mode fork mount SCT.


I would think that an alt-az fork mounted SCT would have trouble with Dobson's Hole.

#62 amicus sidera

amicus sidera

    Skylab

  • *****
  • Posts: 4047
  • Joined: 14 Oct 2011
  • Loc: East of the Sun, West of the Moon...

Posted 22 January 2014 - 02:59 PM

Yes, they certainly do; or rather, the observer does, due to eyepiece positioning.

#63 evilmedic13

evilmedic13

    Explorer 1

  • -----
  • Posts: 95
  • Joined: 22 Jun 2012
  • Loc: Chicago,Il

Posted 22 January 2014 - 03:16 PM

Not sure about disposable, but my luck absolutely sucked last year with anything that had electronics in it. My Nexstar11gps, CG-5, and AVX, all crapped out on me. The 11, and 5 went out in June. The 11 was bought used the September before, and the 5 was only 6 months old. The 11 was not a cheap fix ($800, including shipping) and the 5 was warranty. The AVX died on its 5th use! They just swapped out the whole thing, due to ongoing issues with some boards I guess.
Not a good trend, but Celestron made better what they could, and I'm glad. If it was "disposable" I really don't think they would've been as quick to rectify everything as they were. So, some would see it opposite the way I do, and have given up. Others, like myself, see it as one of the risks with electronic equipment.
It may help that I was a Sonar Technician on submarines a long time ago. I learned that even toilets break when you least expect it. Luckily, it never broke on me. Lol

#64 Chaz659

Chaz659

    Mariner 2

  • -----
  • Posts: 247
  • Joined: 08 Dec 2012
  • Loc: Islip, NY

Posted 22 January 2014 - 03:32 PM

Another bubblehead? I think you are the second or third one I've found on this forum. ET2/SS here. SSBN 659 Gold Crew. On my boat, one guy earned the "Golden Crapper" award not once, but twice, the same night. Sometimes, even with toilets, it's operator error. Not me thank God...

#65 rmollise

rmollise

    Hubble

  • *****
  • Posts: 15469
  • Joined: 06 Jul 2007

Posted 22 January 2014 - 06:55 PM

Normally I agree with Rod (except when he discusses my former employer LOL).

I find a SCT on an equatorially mounted fork to be much more comfortable to use than when mounted alt-az. Easy to see the whole sky from a single standing observing position.


Yeah, it's all bluebirds, puppies, and daisies...till you get near the pole. Anywhere near the pole. :lol:

#66 evilmedic13

evilmedic13

    Explorer 1

  • -----
  • Posts: 95
  • Joined: 22 Jun 2012
  • Loc: Chicago,Il

Posted 22 January 2014 - 08:26 PM

Another bubblehead? I think you are the second or third one I've found on this forum. ET2/SS here. SSBN 659 Gold Crew. On my boat, one guy earned the "Golden Crapper" award not once, but twice, the same night. Sometimes, even with toilets, it's operator error. Not me thank God...

Lol. I always looked for bubbles. STS2/SS USS HAMMERHEAD, and Spadefish. Yep, a river rat too!

#67 Jon Rista

Jon Rista

    Vanguard

  • -----
  • Posts: 2281
  • Joined: 10 Jan 2014
  • Loc: Colorado

Posted 23 January 2014 - 02:01 AM

Well, I figure I'll just dive in, even though this is like my third post. In response to the OP, how would something like the Celestron CGEM Pro mount fit in there? I am in the market for a telescope, I have been for some time and the funds will finally be coming together sometime this year.

I keep debating which mount to get...the Celestron CGEM DX or the Celestron CGEM Pro. The DX is a nice mount, lot of people have it, no one really seems to complain about it. The CGEM Pro, however...it is the only thing on the market except maybe Meade's new mount that "looks" like am amazing feat of engineering.

But...does that matter? Is the CGEM Pro worth the extra price over the CGEM DX? Or is the DX more than capable, and something that could last for the next decade or two just as well as the Pro?

#68 wargrafix

wargrafix

    Messenger

  • -----
  • Posts: 414
  • Joined: 10 Apr 2013
  • Loc: Trinidad

Posted 24 January 2014 - 02:47 PM

anything treated well will last a long time. Mechanics will fail, that's a reality. The classics we see are the ones which were well built had survived, but the ones that didn't will, you will hear the sounds of crickets.


Made in China is a subjective thing since there are high quality items made in china. If companies buy low end items from the factories...guess what? I know first hand of this.

#69 OrlandoMatt

OrlandoMatt

    Ranger 4

  • -----
  • Posts: 351
  • Joined: 22 Nov 2013
  • Loc: Orlando, FL

Posted 24 January 2014 - 04:39 PM

I've always figured down the line if I get several good years of good use out of it before it craps out, just deforking it and putting it on a AVX or whatever they have at that time.

It'll die someday maybe but I'm ok with that, it's not like you have to throw the tube away.

#70 JMW

JMW

    Apollo

  • -----
  • Posts: 1389
  • Joined: 11 Feb 2007
  • Loc: Nevada

Posted 24 January 2014 - 05:52 PM

My CPC925 lasted about 4 years before the Alt motor became intermittent. Eventually I removed the OTA and it lived on an Atlas mount. Sold both later when I bought a AP900GTO. I use the AP mount with refractors and an C11EdgeHD. The C11EdgeHD is a heck of a lot easier to manage than the upper assembly of my old CPC925. I do monthly volunteer public outreach with our Planetarium's CPC11 scopes so I still have the regular experience of lifting the upper motor/scope assembly onto the pier.

I sometimes use my C11EdgeHD on a DM6 mount. Pretty easy to setup but refractor's wider fields of view are better suited to non-tracking mounts.

#71 Stargazer3236

Stargazer3236

    Vostok 1

  • *****
  • Posts: 139
  • Joined: 07 Aug 2010
  • Loc: Waltham, MA

Posted 25 January 2014 - 12:45 PM

I am currently using the CG5-ASGT mount with my C11. I find the setup to be quite stable and very enjoyable to use. In my light polluted neighborhood, I have no problems viewing the planets, but need to get to darker skies for DSO's. I am considering getting the CGEM mount which can handle the weight of my C11 plus all the accessories I like to use. I will keep the CG5-ASGT for my NExstar 8SE to use in GEM mode and not alt-az mode, but will keep the Nexstar base for use in the winter when it gets too cold outside to fiddle with aligning a GEM when my fingers freeze long before the corrector plate does.

#72 DTH

DTH

    Vostok 1

  • -----
  • Posts: 111
  • Joined: 11 Aug 2013
  • Loc: Georgia

Posted 25 January 2014 - 06:42 PM

In Astronomy, "deforked" sounds like such a dirty word. I don't expect my CPC 1100 electronics to last forever. If/when the electronics die, I will use it manually. Heck I use it manually a lot any way. By then I hope I'm pretty good at star hopping. This may sound like a dumb question, but if the gears mess up, can I still use my CPC manually?

#73 gunfighter48

gunfighter48

    Ranger 4

  • *****
  • Posts: 375
  • Joined: 18 Mar 2013
  • Loc: Mill Creek, Washington

Posted 25 January 2014 - 09:01 PM

I have a Meade 2080 that was made sometime in the mid 80's to early 90's and it's still going strong after all these years.. The mirror is as good today as it was in 2000 when I bought it from the second owner. It has standard coatings as far as I can tell. But the mirror is very very good. It beat out several 8" newts, a couple of 10" Dobs (remember this was 2000 - 2002), and a couple of other 8" SCTs in side by side comparisons. No one could figure out why it was that good optically. I guess I just got lucky.

The only reason I bought the Meade LS8 was the light weight. My back and knees took a real beating since 2004. A light weight scope is now a must for me.

#74 rmollise

rmollise

    Hubble

  • *****
  • Posts: 15469
  • Joined: 06 Jul 2007

Posted 26 January 2014 - 10:39 AM

In Astronomy, "deforked" sounds like such a dirty word. I don't expect my CPC 1100 electronics to last forever. If/when the electronics die, I will use it manually. Heck I use it manually a lot any way. By then I hope I'm pretty good at star hopping. This may sound like a dumb question, but if the gears mess up, can I still use my CPC manually?


The gears are not likely to "mess up," so don't worry about it. And if by "manually," you mean loosening the clutches and moving it by hand...the gears are not involved in that. ;)

#75 stevew

stevew

    Now I've done it

  • -----
  • Posts: 4295
  • Joined: 03 Mar 2006
  • Loc: British Columbia Canada

Posted 26 January 2014 - 03:35 PM

As far as the longevity of modern SCT's is concerned obviously the OP is concerned more about the mount, as we all know that SCT optical tubes will still be in use after decades of service.
If a 'Go To" mount gets you outside more often, then good for you. Personally I still prefer the thrill of the hunt.
I tried a "Go To" mount once, and I found myself looking at the hand controller more than the sky. After the hand controller died twice within the first 3 months, I got rid of the go to mount as I wanted a mount that I could use for 20 plus years with out any problems. I bought a standard issue G-11 and have been very happy.
Just like John Lennon once said...
'What ever gets you through the night".... :lol:

Steve






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics