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Charlie HeinAdministrator
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Megrez 90 FD - Fluorite doublet review
      #5657779 - 02/02/13 09:34 AM

Megrez 90 FD - Fluorite doublet review

By Gianluca Rossi


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FirstSight
Duke of Deneb
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Reged: 12/26/05

Loc: Raleigh, NC
Re: Megrez 90 FD - Fluorite doublet review new [Re: Charlie Hein]
      #5657953 - 02/02/13 11:26 AM

I also have a Megrez 90, and I would concur with your review. One point you made bears emphasis: the "rotatable focuser" feature unfortunately renders the focuser body extremely vulnerable to becoming misaligned with the optical tube, thereby introducing noticeable aberration of images. To fix this problem requires tightening the retention screws well past the point where the focuser becomes fixed and no longer rotatable. IMHO it's not easily feasible in a night observing environment to loosen the screws enough to facilitate rotation and then sufficiently retighten them, without risking introducion of misalignment between the focuser body and the OTA. Accordingly, I quit using this feature and instead found that loosening the mounting rings enough to rotate the OTA to the desired orientation effectively accomplished the same purpose with only trivial extra effort.

My particular Megrez 90 is the version with a permanently affixed mounting shoe on the end of the OTA near the focuser (I believe there was for awhile a later version available without this feature). Because this mounting shoe has a permanently fixed position on the OTA, it cannot be used to adjust the OTA's balance in a similar manner to a clamshell. If you're going to use the mounting shoe, it must be attached to the mount in a fashion allowing the OTA to be adjusted sufficiently forward or backward in the mount to enable balancing of the scope, e.g. by bolting a dovetail-fitting rail to the mounting shoe. However, keeping even a short rail attached to the OTA makes it difficult to impossible to fit the OTA back into its case. Alternatively you mount the OTA using rings, the fixed mounting shoe on the OTA becomes little more than a useless obstacle, forcing you to mount the rings farther forward on the OTA than would ordinarily be ideal, since the Megrez 90 has a quite definitely back-heavy center of mass (i.e. toward the focuser end, where the fixed mounting shoe is). Depending on the configuration of your mount's clamping mechanism, if you use rings to mount the Megrez-90, this issue of the (unused) mounting shoe interfering with ideal placement of the rings can be resolved by sliding the saddle plate the rings are attached to forward in the mount's clamping mechanism.

As to optical quality, I'd second your opinion. Only with the very brightest objects such as the lunar limb and Venus is a slight tinge of false color visible. It's a great value in its price range for a really good semi-apochromat, light and compact enough to make a capable, yet highly portable grab n'go scope. Unsurprisingly it falls short of the build, mechanical, or optical quality of an NP-101 (my other refractor). Nevertheless, I would highly recommend the Megrez-90 for anyone wanting a capable grab n'go scope a substantial step up from cheaper apochromats, but without the desire (or perhaps budget) to step up into the significantly more expensive flight of premium true APO refractors.

Edited by FirstSight (02/02/13 12:15 PM)


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Kon Dealer
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Reged: 01/05/11

Loc: Cambridge UK
Re: Megrez 90 FD - Fluorite doublet review new [Re: FirstSight]
      #5658727 - 02/02/13 06:52 PM

I HAD a Megrez 90. The most useless scope it has ever been my misfortune to own.
After 8 months, 3 trips back to WO, they finally bought the useless heap of junk back off me.

So scarred was the dealer, who had the misfortune to be my go-between, he stopped selling WO scopes.

On the plus side I picked up a second hand Kson1026ED to be a backup while I waited for a working WO scope. It has now become my "keeper"- better in every way than the WO heap of junk.
Sorry about the rant, but this is my personal experience.
Well done and good luck if you get a good WO scope. I'm sure they exist, but they are not worth the risk.


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FirstSight
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Reged: 12/26/05

Loc: Raleigh, NC
Re: Megrez 90 FD - Fluorite doublet review new [Re: Kon Dealer]
      #5661818 - 02/04/13 01:46 PM

Quote:

I HAD a Megrez 90. The most useless scope it has ever been my misfortune to own.
After 8 months, 3 trips back to WO, they finally bought the useless heap of junk back off me. etc. etc.




With perhaps a few rare exceptions, someone, somewhere, at sometime has thought they had a bad experience with just about any maker/vendor of astronomy equipment in existence. However, simply stating that the particular WO scope you purchased was "useless" or "junk" is totally unhelpful to the rest of us when you don't tell us in what particular respects you found the scope defective. Was it the optics? The build quality of some particular parts? What?

You'll notice that both the original reviewer and I, in my added comments, noted with particularity the aspects of the scope which we found somewhat problematic or not-quite optimal, albeit in the context that both of us had overall positive impressions of the scope, the stated caveats notwithstanding. I don't think the Megrez 90 is the most perfect scope ever, but I'm left totally baffled by your comments just what you found so unacceptably awful about it, because you give no particulars whatever.

I too have had an unacceptably bad experience with a scope I considered a complete piece of junk from a supposedly "name" maker (I only later learned that though this particular maker does make some respectably decent-quality scopes for the "serious" amateur astronomy market, they also make department-store junk refractors, which is what I had). However, whenever I've voiced harsh complaints about this particular scope (and I've used the term "utter pice of junk" in describing it)...I've also specified the reasons WHY it was complete junk (wobbly tripod, terrible optics and strong chromatic aberration, abysmal-quality eyepieces, plastic focuser gears, etc)...in other words I've given helpful specifics WHY IMHO I'd strongly recommend against anyone purchasing any similar scopes from this vendor. And BTW did I mention it was an utter useless piece of junk? Just in case I forgot, it was an utter useless piece of junk. But the information I gave made it useful to others to understand the reasons why FWIW, instead of simply being a flaming rant.

Edited by FirstSight (02/04/13 05:00 PM)


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iceblaze
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Reged: 10/15/11

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Re: Megrez 90 FD - Fluorite doublet review new [Re: FirstSight]
      #5662029 - 02/04/13 03:51 PM

Chris has it right. Let's play nice from now on. No more flames please.

-James


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Kunama
professor emeritus


Reged: 10/22/12

Re: Megrez 90 FD - Fluorite doublet review new [Re: iceblaze]
      #5662295 - 02/04/13 06:51 PM

I think what KsonDealer meant to say was:

"Good-looking, good optics, nice and short.
BUT completely rubbish focuser. "

or at least that's how he reviewed it on Stargazers.


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Trevor Durity
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Reged: 12/01/05

Loc: Galway, Ireland
Re: Megrez 90 FD - Fluorite doublet review new [Re: Kunama]
      #5662379 - 02/04/13 07:53 PM

I've gone through quite a few scopes over the years and my all time favourite so far has been the WO 90FD (original version with the mounting shoe). Nice optics, hardly any false colour and quite portable.

My only gripe would be the strength of the focuser holding a heavy dslr (7d or 5d) at near zenith with a focal reducer - that does require quite a bit of tightening.

A very enjoyable scope to use though. Pin sharp stars. That said, I haven't had the opportunity to use premium APO like a Tak or AP as of yet.


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Kon Dealer
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Reged: 01/05/11

Loc: Cambridge UK
Re: Megrez 90 FD - Fluorite doublet review new [Re: Trevor Durity]
      #5662923 - 02/05/13 05:01 AM

Firstsight- the Megrez 90 was my first telescope from a a "better-quality" producer.
I had persistent and terminal problems with the "power linear" focuser which was incapable of racking in a 1.25" diagonal and EP at anything above 30 degrees elevation.
I nver had the opportunity to get a single nights viewing in almost a year of ownership.
The vendor tried to repair it, WO tried to repair it and returned it no better. The vendor sent it back and on its return, said I should not bother to collect as it was in an even worse state.
After this WO sent one of their new DDG rack and pinion focusers, which neither racked, nor displayed.
At this point the vendor sent the whole lot back and asked for a refund.
This eventually came, but such was the vendor's (who was excellent and supportive throughout) experience of dealing with WO in this matter, plus his experience with some of WO's newer products, that he terminated his contract with them. He is now a vendor for another make.
Oh yes and the optics were poor out of the box, they needed collimation- another trip to the vendor.
That is why I will not buy another WO scope.


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SteveG
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Re: Megrez 90 FD - Fluorite doublet review new [Re: Kon Dealer]
      #5663616 - 02/05/13 01:54 PM

Well as stated above, just about any manufacturer has made a bad scope or sold a scope with a poor focuser. For what it's worth, I've had 3 William Optics scopes, all 3 had excellent, perfect working focusers (I'm visual only), and superior optics. My ED120 focuser matches the performance of my Moonlite that I mounted on my Meade reflector. The original Meade focuser was really bad! I've read many reviews of the WO 90, and they always rave about the optics of this scope. It's a shame that they do put out scopes with bad focusers - yes this is a problem with WO, and many other brands as well.

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Kon Dealer
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Reged: 01/05/11

Loc: Cambridge UK
Re: Megrez 90 FD - Fluorite doublet review new [Re: SteveG]
      #5663888 - 02/05/13 04:24 PM

Quote:

Well as stated above, just about any manufacturer has made a bad scope or sold a scope with a poor focuser. For what it's worth, I've had 3 William Optics scopes, all 3 had excellent, perfect working focusers (I'm visual only), and superior optics. My ED120 focuser matches the performance of my Moonlite that I mounted on my Meade reflector. The original Meade focuser was really bad! I've read many reviews of the WO 90, and they always rave about the optics of this scope. It's a shame that they do put out scopes with bad focusers - yes this is a problem with WO, and many other brands as well.



Not just one focuser was rubbish. Two were and of different types (Crayford and R&P.
By way of contrast the focuser on my Kson is excellent


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Gianluca67
sage


Reged: 11/26/08

Loc: Italy
Re: Megrez 90 FD - Fluorite doublet review new [Re: Kon Dealer]
      #5694914 - 02/22/13 02:56 PM

Thank you all for replying to my review. As stated by many of you and based also on my personal experience I think that the cons. of the Megrez 90FD is essentially the focuser, good for visual oberserving in my case but inadequate for astrophotography in my experience. My Megrez 90 was definitely off spec (miscollimation, the power linear focuser is not Crayford design as advertised and it is not a treat to use as advertised, the fine focusing knob has a ratio 1:9 instead of 1:10...). With some tweaking however you can turn the Megrez 90 into a very good grab and go telescope for visual observing and for astrophotography that may be close to true Apo refractors at a fraction of the cost.
Thank you for reading my review

Gianluca


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RAKing
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Re: Megrez 90 FD - Fluorite doublet review new [Re: Gianluca67]
      #5695403 - 02/22/13 07:04 PM

Gianluca,

I thought your review was fair and accurate.

I have owned three WO scopes and the focuser has been the 'weakest link' in all of them. I recently traded my WO 110 FLT to a friend for his WO 90 Megrez. (He wanted more aperture for his imaging and I wanted something smaller and lighter for grab and go.)

The optics are great in mine and they haven't been an issue. I am not thrilled with the "foot" on the Megrez, but I can work around that. But I just finally had to do something with the slippery focuser and the easiest fix for me was to toss the stock focuser and upgrade to a FeatherTouch. Now I am very happy with my little scope.

Cheers,

Ron


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Kon Dealer
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Reged: 01/05/11

Loc: Cambridge UK
Re: Megrez 90 FD - Fluorite doublet review new [Re: RAKing]
      #5701017 - 02/26/13 04:47 AM

Prettyy poor show when you have to routinely replace the focusser of an "above marketplace average" product.
All style and no substance.


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tboconnor
member


Reged: 01/14/10

Re: Megrez 90 FD - Fluorite doublet review new [Re: Kon Dealer]
      #5819322 - 04/24/13 09:04 AM

Ive got one of original Megrez 90's. I really dont understand why people *BLEEP* about the focuser. I find it totally fine. I routinely hang a heavy DSLR off it, and its never slipped once.

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inZet
member


Reged: 02/12/09

Loc: Milan, Italy
Re: Megrez 90 FD - Fluorite doublet review new [Re: tboconnor]
      #5819557 - 04/24/13 11:23 AM

The problem with WO is they change specs without renaming the products. This generates confusion among the users.
There are two flavors of Megrez 90: the old one f/6.9 and the newer f6.2. They are completely different optically speaking, designed for different applications. The M90 f/6.9 can be recognized by the L-bar permanently attached. The f/6.2 was produced with two types of focusers.
So when you read articles around... be careful which one they are referring to.
I own the oldest f6.9, which I consider excellent from all point of views.

Gianluca

Edited by inZet (04/24/13 11:27 AM)


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pedrete
member


Reged: 01/05/11

Re: Megrez 90 FD - Fluorite doublet review new [Re: tboconnor]
      #5819575 - 04/24/13 11:35 AM

My Megrez 90 FD also is a very good optics grab & go scope. I'm quite happy with the optics but the original Crayford focuser failed, very slippery. Replaced it with a Feather Touch and glad I did it.

Another typical experience for what I can see in the previous messages. A friend of mine, industrial engineer, disassembled the focuser and found the problem. The metal sheet where the friction is applied was no longer straight so the focuser slipped.

Thank you for the review, Gianluca.


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tboconnor
member


Reged: 01/14/10

Re: Megrez 90 FD - Fluorite doublet review new [Re: inZet]
      #5820778 - 04/24/13 08:43 PM

Quote:

The problem with WO is they change specs without renaming the products. This generates confusion among the users.
There are two flavors of Megrez 90: the old one f/6.9 and the newer f6.2. They are completely different optically speaking, designed for different applications. The M90 f/6.9 can be recognized by the L-bar permanently attached. The f/6.2 was produced with two types of focusers.
So when you read articles around... be careful which one they are referring to.
I own the oldest f6.9, which I consider excellent from all point of views.

Gianluca




Mine the the f6.9 version with the annoying metal foot Glad I got one with a decent focuser


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