Jump to content


Photo

Replacement Scope Advice

  • Please log in to reply
17 replies to this topic

#1 MattS

MattS

    Explorer 1

  • -----
  • Posts: 54
  • Joined: 24 Feb 2013

Posted 07 August 2013 - 12:26 PM

Dear All

For much of this year I have investigated possible replacement scopes for my venerable ETX-90 scope; specifically the LX90 and LX200 ACF, perhaps coupled with a more intuitive planetarium suite/interface such as SkySafari/SkyFi.

My requirements are that I intend to use this scope primarily for visual astronomy, while retaining some flexibility towards basic AP idc, in a back garden that is moderately light polluted. Unfortunately, I do not have room for a permanent pier-mounting, so the scope will be moved into position for every session. Lastly, I want the GOTO and tracking performance of the mount to be hugely superior to my ETX (i.e. no rubber-banding etc, which I am assured that the LX90/200 will provide, given appropriate attention during setup etc).

However before I commit, I would be grateful if an 'independent voice of reason' could suggest an alternative telescope/mount combination instead?! After a quick look on the web it appears that the CPC 800/925 XLT or CGEM 800 might be suitable, but I know nothing about them, or Celestron. In particular, are the Celestron mounts significantly better than their Meade counterparts?

I should also state that my budget extends between £2-2.5K.

Any advice would be most welcome!

MS :question:

#2 MikeBOKC

MikeBOKC

    Aurora

  • *****
  • Posts: 4665
  • Joined: 10 May 2010
  • Loc: Oklahoma City, OK

Posted 07 August 2013 - 01:01 PM

Visually you should find no appreciable difference between the Celestron and Meade SCTs. Operationally, the Celestron hand controllers and setup/alignment procedures are considered by many to be simpler and more reliable than Meade's. Overall most people with the CPC scopes are quite happy with them, if several years of posts on this forum are a reliable measure.

#3 Stacy

Stacy

    Star Partyer

  • *****
  • Posts: 5037
  • Joined: 15 Sep 2002
  • Loc: Seattle, WA

Posted 07 August 2013 - 01:11 PM

Visually you should find no appreciable difference between the Celestron and Meade SCTs. Operationally, the Celestron hand controllers and setup/alignment procedures are considered by many to be simpler and more reliable than Meade's. Overall most people with the CPC scopes are quite happy with them, if several years of posts on this forum are a reliable measure.


Yup. :ubetcha:

#4 Digital Don

Digital Don

    Vanguard

  • *****
  • Posts: 2165
  • Joined: 20 Jan 2004
  • Loc: Manteno, IL

Posted 07 August 2013 - 02:28 PM

Hi Matt,

I've owned scopes from Celestron and Meade and both make good products. Based on my experiences over the past 35 years however, I would have to recommend Celestron over Meade.

Meade is currently offering a 14" f/8 LX-600. While it would probably be the 'perfect' scope for my observatory, I won't even consider it unless Meade's current financial situation is resolved.

To me, the availability of service after the sale is just as important as the product. This is especially true with astronomical equipment.

Don:usa:

#5 MattS

MattS

    Explorer 1

  • -----
  • Posts: 54
  • Joined: 24 Feb 2013

Posted 08 August 2013 - 03:32 AM

Hi Don

Thanks for this. I agree that Meade's current financial woes don't exactly inspire confidence.

As I mentioned, I am interested in the CPC as an alternative to the LX90/200. In your experience, are there any obvious reasons why the Celestron outperforms the Meade? Is it the quality of the mount and, if so, why?

Thanks, MS

#6 brianb11213

brianb11213

    Cosmos

  • *****
  • Posts: 9047
  • Joined: 25 Feb 2009
  • Loc: 55.215N 6.554W

Posted 08 August 2013 - 06:11 AM

As I mentioned, I am interested in the CPC as an alternative to the LX90/200. In your experience, are there any obvious reasons why the Celestron outperforms the Meade? Is it the quality of the mount and, if so, why?

Ok. I used to own a LX90 (8") and upgraded to a CPC1100.

The CPC mount is a lot steadier than the LX90 mount. It also aligns more relaibly and more easily (in my opinion) and point & tracks more accurately. I think the LX200 mount is about the same as the CPC mount in terms of performance, but it's heavier and less ergonomic. The LX90 is much lighter, but then the Celestron SE mount is lighter still, and a lot more convenient in terms of being easily able to remove the tube for carriage / storage and not needing a balance weight; but then the stability & pointing accuracy of the SE mount is so poor that it should be discounted.

The optics in my CPC1100 are considerably better than those in the LX90 I used to own. In terms of the appearance of the well collimated, in focus image of a single star at very high magnification. But then there seems to be a fair bit of variability in both ... these are after all mass produced scopes, not hand finished at premium price.

#7 MattS

MattS

    Explorer 1

  • -----
  • Posts: 54
  • Joined: 24 Feb 2013

Posted 08 August 2013 - 09:12 AM

Hi Brian (everyone)

Thanks for your input. At the moment, the CPC925 retails inbetween the LX90 8 and 10" - closer to the 8". With this in mind, would I be correct to assume that you would recommend the CPC925?

To be honest its the performance of the mount that bothers me most: have you had any problems with yours?

Cheers, MS

#8 brianb11213

brianb11213

    Cosmos

  • *****
  • Posts: 9047
  • Joined: 25 Feb 2009
  • Loc: 55.215N 6.554W

Posted 08 August 2013 - 10:43 AM

At the moment, the CPC925 retails inbetween the LX90 8 and 10" - closer to the 8". With this in mind, would I be correct to assume that you would recommend the CPC925?

The 925 is a little odd: the tube length is about the same as the 1100: the primary mirror is f/2.5 rather than f/2 as is usual with SCTs. Maybe for that reason, some planetary imagers reckon that the 925 gives sharper images than the 900 or the 1100, though there's more actual detail resolved in an 1100 with a slightly fuzzy image than in a 925 with a perfectly sharp one. This is hearsay so far as I'm concerned as I have never actually owned a 925. But the issue is that the 925 and the 1100 are fairly similar in bulk and there isn't too much weight difference either.

The big gain on the 925 is that the tube is much better balanced than the 1100 - which needs a substantial noseweight.

To be honest its the performance of the mount that bothers me most: have you had any problems with yours?


Mount issues on the CPC1100: the clutches aren't brilliant especially if you have a habit of not balancing the tube accurately: eventually they need to be adjusted & this is either a trip back to the dealer or a fairly complex DIY job. Otherwise, minor. The red power indicator LED is waaaay too bright but can be defeated with a short piece of electrical tape or a blob of black paint. The power lead socket can be unreliable - it rotates in azimuth with the mount & rotation can cause the lead to pull out or break electrical connectivity, which is annoying as the computer gets reset. That's easily fixed by taping the top end of the power lead securely to the fork arm. TBH the LX90 mount has pretty much the same issues.

There is not much difference in capability between the Meade & Celestron handset controllers ... I personally prefer the menu layout in the Celestron unit ... which maybe indicates quite a big difference in the Celestron's favour as I'm pretty normal in that I tend to prefer what I had first.

#9 MattS

MattS

    Explorer 1

  • -----
  • Posts: 54
  • Joined: 24 Feb 2013

Posted 08 August 2013 - 01:28 PM

Hi Brian - that's great, thanks for the info.

Any other opinions out there?

MS

#10 Bruce N

Bruce N

    Explorer 1

  • -----
  • Posts: 52
  • Joined: 01 Apr 2013

Posted 08 August 2013 - 03:26 PM

I wouldn't buy anything from Meade at this time. I had a bad experience with them shipping damaged products, incomplete shipments and low levels of stock available. I suspect that in response to their financial problems they have cut back staff staff in quality control and other vital areas. After fighting with them about an LX90, I purchased a CPC800 that I am very happy with.

#11 Digital Don

Digital Don

    Vanguard

  • *****
  • Posts: 2165
  • Joined: 20 Jan 2004
  • Loc: Manteno, IL

Posted 08 August 2013 - 08:57 PM

Hi Don

As I mentioned, I am interested in the CPC as an alternative to the LX90/200. In your experience, are there any obvious reasons why the Celestron outperforms the Meade? Is it the quality of the mount and, if so, why?

Thanks, MS


Hi Matt,

I can only describe my experience with the CPC scopes. I installed a CPC 1100 in my backyard observatory about 5 years ago and I've been satisfied with it's performance since day one. In fact, I was so impressed with it's performance and ease of use that I sold my previous 'travel scope' and replaced it with a CPC 800.

As far as a comparison - assuming both are working properly - you really wouldn't see much of a difference between Celestron and Meade scopes of similar aperture.

Meade is currently offering a fork-mounted, 14" f/8 Schmidt-Cassegrain. Despite the fact that this would probably be the "perfect" scope for my observatory, I woudn't even consider it unless and until Meade resolves it's financial issues.

Don:usa:

#12 barbarosa

barbarosa

    Viking 1

  • -----
  • Posts: 875
  • Joined: 11 Apr 2010
  • Loc: 37°50'N

Posted 08 August 2013 - 09:43 PM

Mount issues on the CPC1100: the clutches aren't brilliant especially if you have a habit of not balancing the tube accurately: eventually they need to be adjusted & this is either a trip back to the dealer or a fairly complex DIY job.


I might have this wrong but i don't see how the CPC clutches will need adjustment or could be adjusted. If you tighten the quick release knobs sufficently to prevent slipping under load before engaging power there should be no appreciable slippage or wear. AFAIK there is nothing to adjust in the CPC clutch.

If because of a high unbalanced load the clutch cannot be tightened enough to prevent slippage the problem is the load and not the cluth design. I suppose the polymer disk clutch could wear out, but then service would be to replace the disk.

That job would be simple and require no special tools or knowledge, but it would not be DIY unless Celestron begins selling the disks. Celestron does not sell that disk at retail curently and may never have done so.

If it did fail and no new replacement could be found I think a servicable disk could be cut from any of several different plastics or even cork. But I expect never to find out. ;)

#13 brianb11213

brianb11213

    Cosmos

  • *****
  • Posts: 9047
  • Joined: 25 Feb 2009
  • Loc: 55.215N 6.554W

Posted 09 August 2013 - 04:55 AM

I might have this wrong but i don't see how the CPC clutches will need adjustment or could be adjusted.

There have been several threads on this in these forums.

The basic issue is that the clutch action becomes increasingly "sticky" in its action with the result that you either overtighten it, or it's prone to slipping.

I agree that accurate balance tends to make the issue worse. However since the CPC1100 tube is waaay out of balance as supplied, and only gets worse when decent quality 2" fittings are used instead of the cheap, nasty but light 1.25" fittings supplied, a certain amount of imbalance is inevitable.

You curse bad clutches when they start slipping halfway through a session - forcing you to go through the alignment procedure again, wasting valuable observing time - or when you have extreme difficulty slackening them off again when packing up.

#14 Bob Griffiths

Bob Griffiths

    Getting Grouchy

  • *****
  • Posts: 10674
  • Joined: 10 Oct 2005
  • Loc: Frederick Maryland

Posted 09 August 2013 - 11:58 AM

Matt...I answered your post on the "other" Astronomy forum...

But I stand my my opinion that the Meade ACF optics are worth all of 20 bucks MORE then the standard Celestron Optics especially if you tend to not view on axis and like to hang out along the extreme edge of the FOV...

The HC was the major reason I went with a CPC and I already owned another Celestron as well as an Autostar Controlled Meade mount The Autostar is fine but I spend too much time scrolling thru menu after menu to do simple things with the Autostar


Bob G

#15 MattS

MattS

    Explorer 1

  • -----
  • Posts: 54
  • Joined: 24 Feb 2013

Posted 09 August 2013 - 04:05 PM

Bob - just read both of you replies. Cheers for the advice. After spending the best part of a year finding my next Meade scope, I am mightily surprised to find that I'm favouring the Celestron 925 instead!

Everyone - many thanks for your advice. You may just have made me a Celestron convert!

Cheers all!

#16 dwitek

dwitek

    Mariner 2

  • *****
  • Posts: 292
  • Joined: 03 Jul 2008
  • Loc: White Lake, Michigan

Posted 10 August 2013 - 08:42 AM

I've owned an older LX5 8" which had great optics but dates back to the 80's. Then, I had a 10" LX200 with not-so-good optics, in my opinion, but I bought it used. I now have a 12" ACF on a Celestron CGE mount. Again, the optics are so-so IMHO. I have a CPC925 which seems, to me, to have much better optics than my ACF. Part of my problem, I think, is that the seeing in the upper midwest of the US is not very steady and possibly the 12" amplifies the bad seeing.

As far as the mounts I always felt very confident in my LX200 mount. I had it on a wedge and, once aligned, was rock steady an extremely accurate thoughout the entire sky. The CPC is easy to align but even using a 6mm illuminated reticle I can never seem to get as accurate a GOTO as I could throughout the entire sky as I could with the LX200. Could be the difference between Alt-Az on the CPC and using the LX200 in EQ mode.

I do like the Celestron menu hierarchy better than the LX200 and I, too, worry about Meade's status and moving manufacturing to Mexico.

#17 NorthernSoul man

NorthernSoul man

    Explorer 1

  • -----
  • Posts: 81
  • Joined: 22 Oct 2012
  • Loc: Rowley Regis. UK

Posted 26 August 2013 - 01:10 PM

Hi MattS - not sure of your location (I'm mid UK), from a purely visual aspect I owned the LX90 8" for about 5 years, previously had an 8" F8 newt with Hinds optics (UK based and really nice !!!).
I done a great deal of research, wether to go for an SCT or another newt, but settled on a second hand LX90, over the 5 years or so I never had a problem with it and it worked flawlessly, maybe the planetary views were a little "dull" compared to the newt but I managed very well with it.
Came to the upgrade from the LX90 to the CPC 1100 - not really a large increase in detail, maybe a slightly brighter image than in the Meade, but way heavier to move around - you really don't want to carry the CPC any distance.
The mounting being AltAz really works well,the double fork mount is way better than the newer single fork mounts I think, for the 11" anyway - just a point here though, an increase in aperture brings an increase in dew!!! also, an increase in poor atmospherics - I think that's why the 925 came about, for any given night you'll do better with a slightly smaller mirror diameter for better seeing conditions. Some companies put the 11" OTA on the Celestron CG5 mount, I use this mount for a Celestron 127mm Mak, would never put anything larger on the CG5 though. You hear tales regarding the electrics on the Meade's a friend of mine has just got the dreaded "Dec motor runaway problem". Since owning the CPC 1100 I've maybe spent more time on the Planets, some people say that the decrease in contrast steers them away from them, but if your prepared to spend a little more time at the ep, the detail can be teased out, especially the height above the Ecliptic Jupiter was just a few months ago and think the next night time apparition of her will be around the same - Saturn, on the other hand for mid UK latitudes was dreadful.
Another vote for Celestron !!!

#18 MattS

MattS

    Explorer 1

  • -----
  • Posts: 54
  • Joined: 24 Feb 2013

Posted 01 September 2013 - 05:07 AM

Hi NorthernSoul Man

Thanks for your reply - I've been away for a while, hence the delay in responding.

To answer your question, I live just outside Southampton, Hants. The skies are (un)reasonably light polluted, but on a good seeing night I can make out the Milky Way immediately as a faint blur. Not too bad I suppose.

Back to my post. Having asked the question, a month ago I took the time to visit my nearest Celestron dealer. The CPC925 was on display, and I actually mistook it for the 1100; its a beast! Long story short, I ordered the CPC925 along with the SkyQ Wifi gadget. It will arrive soon, but work is taking me away for a while so I'm just going to have to wait! I submitted a post called 'A New Telescope' detailing my experiences/decisions elsewhere in CN. The opinions above helped immensely.

Cheers, MS






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics