230 replies to this topic

[Bonco2]

I don't consider the ETX EC 90  a classic. But the moderators have allowed posts concerning it.

But tonight I finally put the ETX  to the test with fairly steady skies. Very impressed with the sharp views of the moon tonight. Of course no CA issues and very good contrast and details in the Maria and the splash rays from Copernicus. Aristarchus and surrounding rills were oh so sharp. I've found that the 45 diagonal is not good for astro views but fine for nature views. The telescope really performs when using the installed eyepiece slot. What an easy grab and go.

Bill  

[Barlowbill]

I call mine (ETX90-AT) my Moon Killer

[GEC]

My ETX 90 RA has outstanding optics.  It was the one they sold before the goto versions came out.  I bought it new.  I remember taking it to work when I worked mid nights and using it to view and sketch Mars on my lunch breaks during several oppositions.  Good times. I scanned my old sketches into my computer recently. I still have it and use it but on a different mount.  The optics were great but the mount it came with was "user hostile".

 

Clear Skies

 

GEC

[ALman]

I bought the non goto ETX because I liked the look of it. Its a good scope. I have diligently taken it on holiday, tried to do observations under dark skys. I like may of you have loved the idea of this scope.

But... the mount is infuriating. I have used it in AZ mode and in the EQ position on the legs supplied. Ether way it just fights the user at every step. It is very apparent that the addition of GOTO to this mount was critical as the original design was woefully inadequate.

This experience makes me wonder how Questar owners can possibly be so satisfied with this design. This mount is an expression of pure disappointment in Meade and a serious black spot on their good name.

In saying this. I am writing this as I am looking at the moon through my ETX. And I love it and write this as a total hypocrite. Forgive me Meade.

Edited by ALman, 24 May 2021 - 03:36 AM.

[Corcaroli78]

I have bought and sold two ETX90.  The first was a second hand deluxe package including the field tripod. Amazing views with the proper wide field eyepieces. What ireally hated was the finder. it came with the straight one and the one with 45 degree and both were a pain to use. ultimately i replaced it with a red dot finder and things improved a lot.

 

I sold the first to fund another scope and regreted the sale, but another came at a goodrice. this time only the OTA and ...what a surprise!! the optics were much sharper... i used extensively as spotting scope for seabirds and during the night and after some time i sold it again to buy a smaller aperture refractor which provides a little bit more field of view.  I am happy now with my current setup, but i still miss my small ETX... it was so easy to set... maybe i should look for a third one..

 

 

Carlos

[starman876]

Still have the ETX I have owned for years.  It is small enough to store anywhere and the optics are decent for a grab and go scope.  See no reason to sell it.

[Piggyback]

 

Discarding the wiggly fork mount of my ETX 90 for a homemade adaption to my Telementor equatorial, I find this a perfect solution for a stable setup. Solar photography is easy with the Baader camera adaption rail and Thousand Oaks glas filter in front. Had a serious problem on my first use on a hot summer day, though. Ole´secondary was showing a serious case of wanderlust. I was able to stop this joyful careening by applying heat resistant glue to the bottom of the secondary. With that nagging problem out of the way, the little catadioptric is capable of delivering amazingly sharp and contrasty views. Epsilon Lyrae, Mars polar cap, Cassini division. Guess I´m pretty happy with the overall performance of my ETX 90.

[sunrag]

I have two ETX-90s OTAs that i have built into a binoscope.
Quite outstanding for terrestrial use.

[DirtyRod]

I've got one. It was a broken mess when I bought it. A few parts and it's a pretty decent scope. Agree the mount is my biggest issue. Too much play and once in a while it moves after I stop slewing so it  can be frustrating. The optics are very good though. Mine is one of the pre-Go To versions. 

Edited by DirtyRod, 24 May 2021 - 03:23 PM.

[Bonco2]

After owning mine now  for a few months I've come to the conclusion that it's a keeper. For a time I wasn't pleased with the optics but that was when using the 45 deg diagonal. It star tested poorly. But when I tested it with the installed eyepiece port I was amazed. I'll never use GOTO functions for various reasons but I've learned to overcome many of the weaknesses of the mount and hand controller in manual mode. The finder tho is just not right. Shame on Meade. Whoever designed it was not an observer. Regardless this is an excellent optic and used ones go for attractive prices. Deforking it is always an option that I'll be considering. 

Bill 

[CHASLX200]

Many are not collimatied. But can be very sharp.  Now you can sell that 75mm Unitron.

[oldmanastro]

I have owned a USA made ETX90-EC since 2001. It was a birthday gift from my wife. The telescope has served me well on lunar planetary and even DSO observing. My skies were quite good 20 years ago. Now light pollution has taken over. The ETX90EC has never lost it's perfect collimation even though this is the telescope that has taken more car rides than any of the other that I own. The optics are excellent. The mount is fair. I went through two Autostars before giving up on them. I use the mount with the original hand controller and it works acceptably well. How foes it compare the Questar. Well, the Questar has an edge above the ETX but is not a big edge.

Attached Thumbnails

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Edited by oldmanastro, 25 May 2021 - 06:28 PM.

[jgraham]

I luvs my ETX scopes! I happen to own at least one of each major variant including the original ETX-90, sometimes called the ETX-90RA or ETX-90M. Then only significant issue that I have every had with the little ETX is the tiny finder that is very hard to use, even the little right-angle finder. The scope is just too small to squeeze in a finder so close to the eyepiece. To solve this, I have added a Vixen finder bracket to most of my scopes. This lets me mount a real RACI finder, making the scope a joy to use!

 

My ETX-90M...

 

 

 

[DirtyRod]

I luvs my ETX scopes! I happen to own at least one of each major variant including the original ETX-90, sometimes called the ETX-90RA or ETX-90M. Then only significant issue that I have every had with the little ETX is the tiny finder that is very hard to use, even the little right-angle finder. The scope is just too small to squeeze in a finder so close to the eyepiece. To solve this, I have added a Vixen finder bracket to most of my scopes. This lets me mount a real RACI finder, making the scope a joy to use!

 

My ETX-90M...

 

ETX-90M.jpg

Very nice although I'm not familiar with the M and my search didn't find any specifics. What do the adjustments knobs at the bottom and the top of the right fork do? I also see two in the middle of the base that mine don't have. 

[oldmanastro]

I luvs my ETX scopes! I happen to own at least one of each major variant including the original ETX-90, sometimes called the ETX-90RA or ETX-90M. Then only significant issue that I have every had with the little ETX is the tiny finder that is very hard to use, even the little right-angle finder. The scope is just too small to squeeze in a finder so close to the eyepiece. To solve this, I have added a Vixen finder bracket to most of my scopes. This lets me mount a real RACI finder, making the scope a joy to use!

 

My ETX-90M...

 

ETX-90M.jpg

That finder is a wonderful idea. How did you fit the finder base on the tube?

[sdedalus83]

I see plenty of pictures of these with the 45 degree prism but very few with a star diagonal. Do they reach focus when used with an SCT adapter ring or ETX 1.25” VB? How much of an image quality hit does it incur? I’d rather get a Wegat back and rings for mine, but that would triple my investment.

[jgraham]

The original ETX-90 was called just that, the ETX-90. When the GoTo versions came out they were labeled ETX-90EC (electronic controller), AT (Autostar Telescope), and PE (Premium Edition?). To distinguish the original I have seen it referred to as the ETX-90M (manual) or RA (right ascension drive).

 

The knobs on the base include a slow motion knob for the R.A. (azimuth) and an R.A. lock. At the bottom of the right fork is a slow motion Dec (altitude) tangent arm knob and at the top is the axis lock. Mine is mounted on a #884 field tripod with the tilt plate. I use it most of the time in altaz mode as shown, but at high magnifications I raise the tilt plate to 40 degrees and turn on the drive for tracking. It's nice to have options!

 

The Vixen bracket is mounted using two sheet metal screws. I _carefully_ drilled two small pilot holes trying my best to keep tailings from dropping inside the tube (turned out not to be a problem. I then inserted the screws to tap the holes, removed the screws and filed off the tips so that they would not stick into the light path, and re-installed them. I was careful to gently snug the screws to keep from stripping the holes on the tube wall. So far I have done this on all of my ETX Maks (several 90s, a 105, and my 125) and it is a nice modification. I love star-hopping with these and the RACI finder makes all of the difference.

 

Neat stuff.

[LU1AR]

I did a lot of work to improve my ETX-90 RA telescope and shared my experience here:

 

https://www.cloudyni...etx-90-upgrade/

Upgrades include adjusting the table tripod mount, improving motor power and precision, and fine-tuning RA Dec movements.

Regarding the 90º diagonal that comes installed, it is as good as a $ 300 Baader- but you have to adjust it, so that the beam passes exactly through the center of the baffle. This is accomplished with a collimated laser.

I hope this is useful to the lovers of this little giant; that has been with me, for near a quarter of a century.

Edgardo

[Bonco2]

Many are not collimatied. But can be very sharp.  Now you can sell that 75mm Unitron.

Chas,

Not a chance. The Unitron ain't going anywhere soon.

Bill ;-)

[DirtyRod]

The original ETX-90 was called just that, the ETX-90. When the GoTo versions came out they were labeled ETX-90EC (electronic controller), AT (Autostar Telescope), and PE (Premium Edition?). To distinguish the original I have seen it referred to as the ETX-90M (manual) or RA (right ascension drive).

 

The knobs on the base include a slow motion knob for the R.A. (azimuth) and an R.A. lock. At the bottom of the right fork is a slow motion Dec (altitude) tangent arm knob and at the top is the axis lock. Mine is mounted on a #884 field tripod with the tilt plate. I use it most of the time in altaz mode as shown, but at high magnifications I raise the tilt plate to 40 degrees and turn on the drive for tracking. It's nice to have options!

 

The Vixen bracket is mounted using two sheet metal screws. I _carefully_ drilled two small pilot holes trying my best to keep tailings from dropping inside the tube (turned out not to be a problem. I then inserted the screws to tap the holes, removed the screws and filed off the tips so that they would not stick into the light path, and re-installed them. I was careful to gently snug the screws to keep from stripping the holes on the tube wall. So far I have done this on all of my ETX Maks (several 90s, a 105, and my 125) and it is a nice modification. I love star-hopping with these and the RACI finder makes all of the difference.

 

Neat stuff.

Thanks for the education.

[RichA]

I don't consider the ETX EC 90  a classic. But the moderators have allowed posts concerning it.

But tonight I finally put the ETX  to the test with fairly steady skies. Very impressed with the sharp views of the moon tonight. Of course no CA issues and very good contrast and details in the Maria and the splash rays from Copernicus. Aristarchus and surrounding rills were oh so sharp. I've found that the 45 diagonal is not good for astro views but fine for nature views. The telescope really performs when using the installed eyepiece slot. What an easy grab and go.

Bill  

For some reason, the moon is an outstanding target in those ETX90's.  It always looks good.

[Benach]

This experience makes me wonder how Questar owners can possibly be so satisfied with this design. This mount is an expression of pure disappointment in Meade and a serious black spot on their good name.
 

I think I know the answer to that one: A combination of a few things:

- Better mechanical design. For example: an ETX has plastic axes whereas in a Questar they are made from, afaik, aluminium. That is a huge advantage.

- No Goto thus no high precision slewing required just a sychronous motor

- Probably a Questar has preloaded their worms making backlash nearly impossible. With an ETX the wormwheels are too small (about 30mm diameter in the Declination axis) and no preload.

 

etc. etc. but that gives a bit of an idea.

[CHASLX200]

The optics in my first 90's made 90MM were very sharp. I just never liked the finder and mount.  Had a older 125mm vesion that did 600x on the moon.

[RichA]

I think I know the answer to that one: A combination of a few things:

- Better mechanical design. For example: an ETX has plastic axes whereas in a Questar they are made from, afaik, aluminium. That is a huge advantage.

- No Goto thus no high precision slewing required just a sychronous motor

- Probably a Questar has preloaded their worms making backlash nearly impossible. With an ETX the wormwheels are too small (about 30mm diameter in the Declination axis) and no preload.

 

etc. etc. but that gives a bit of an idea.

ETX mounts are crappy plastic.  The rear part of the scope is plastic, with the mirror box.  But,  the OTA from the mirror to the corrector is all machined aluminum.  It's a very solid piece of construction.  If only they'd made a deluxe version with a metal fork mount.

[starman876]

The optics in my first 90's made 90MM were very sharp. I just never liked the finder and mount.  Had a older 125mm vesion that did 600x on the moon.

just about everything will do 600X on the moon   Says so right on the box.

 

https://www.amazon.c...e/dp/B000LJMOYK