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Can I run a Meade EXT90 as a tabletop scope?

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#1 John from CT

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Posted 20 January 2020 - 12:22 PM

I have a almost untouched Meade EXT90 available to me for $80.  I was searching for a diminutive tabletop scope which I can setup superfast and do some quick looking... 

The scope I found doesn't have a tripod available but the base sure looked like it could just sit there and be used.

 

I'm looking for something on the cheap since I have a lots of bigger equipment.  This one seems to have fallen in my lap and I'm curious.  I'm not buying it if it cant be used tabletop

 

john



#2 Augustus

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Posted 20 January 2020 - 12:23 PM

Absolutely. I do all the time. I recommend getting the little legs so it can track in EQ mode.



#3 RaulTheRat

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Posted 20 January 2020 - 12:25 PM

Many years ago I had one of those, and I do recall it being quite wobbly but on the other hand optically excellent and very small and light.

For that price I think you'd be pleased, perhaps you can fashion a way to secure it to the table you'll put it on with a knob or clamp for some stability?

#4 Barlowbill

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Posted 20 January 2020 - 12:29 PM

By the way, it is ETX not EXT


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#5 wrnchhead

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Posted 20 January 2020 - 12:49 PM

I gifted one of these to a friend last Christmas. I got some star time with it beforehand, it's great. It does have a couple of really bad characteristics that I would have to address if I got one. Namely the finder. Easily enough remedied. I had the tripod legs for it, and tried it in EQ and AZ mode. It really was difficult to look at stuff overhead, though this may be a failing of my technique or understanding. But yes, optically excellent and can't argue the price. 



#6 munirocks

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Posted 20 January 2020 - 01:38 PM

It can be used in EQ mode on a table top or tripod but the instructions (supplied with my ETX90 RA version anyway) were written by someone with a fundamental misunderstanding of how the RA ring works on the scope.

 

You calibrate the RA position, with the RA drive running (and after you've polar-aligned), by pointing to a guide star (of known RA value) and then moving the ring so it reads the same value as the RA guide star. The RA ring automatically moves with the rotating top of the base so as the scope tracks, the RA reading stays the same. So far, so good.

 

What the instructions failed to describe is the special technique that you need to use (that is unique to the ETX 90 RA) when you want to pan to a new location. You need to put your thumb on the RA ring and bottom of the base, together, so the ring temporarily STAYS PUT relative to the bottom of the base, while at the same time rotating the top of the scope (letting it slide under the RA ring) to the new position (new RA reading). Then let go of the RA ring.


Edited by munirocks, 20 January 2020 - 01:45 PM.

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#7 John from CT

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Posted 20 January 2020 - 08:29 PM

By the way, it is ETX not EXT

 

Thank you for the clarification.



#8 aeajr

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Posted 20 January 2020 - 11:59 PM

Any of the ETX scopes can be placed on a level table and run in AltAz mode.   However,  how are you going to secure it so you don't accidentally move the base on the table.  If it moves the GoTo alignment will be off.  Give that some consideration. 

 

I have an ETX 80 and 125.  I enjoy them both but I use them on tripods. 



#9 Jon Isaacs

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Posted 21 January 2020 - 12:32 AM

I have a almost untouched Meade EXT90 available to me for $80.  I was searching for a diminutive tabletop scope which I can setup superfast and do some quick looking... 

The scope I found doesn't have a tripod available but the base sure looked like it could just sit there and be used.

 

I'm looking for something on the cheap since I have a lots of bigger equipment.  This one seems to have fallen in my lap and I'm curious.  I'm not buying it if it cant be used tabletop

 

john

 

John:

 

Is this an ETX-90 RA or an ETX-90, AT or EC?  The RA has is a equatorial fork mount, the AT and EC are GOTO Scopes.

 

In general, scopes can be used on tables but they're awkward and not too stable.  The idea seems better than it is.

 

Jon


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#10 SeattleScott

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Posted 21 January 2020 - 12:45 AM

There is no way the stability of these used as table top can compete with a tripod. At least a Starblast has a wide base and big rubber feet. The ETX can be used as table top, and it might even be somewhat stable with the little tripod legs, but the scope really was designed and intended to be used on a tripod. For quick looks I suppose it could work. Hard to imagine using GoTo on a table.

Typically the tube alone sells for around $90 in the classifieds so that is a good price if the motors still work.

Personally for GNG I would want something with a wider view so I don’t have to spend ten minutes of a short session doing a GoTo alignment. But I have taken my ETX 90 (and tripod) out for quick looks at the Moon and planets.

Scott
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#11 Augustus

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Posted 21 January 2020 - 10:06 AM

There is no way the stability of these used as table top can compete with a tripod. At least a Starblast has a wide base and big rubber feet. The ETX can be used as table top, and it might even be somewhat stable with the little tripod legs, but the scope really was designed and intended to be used on a tripod. For quick looks I suppose it could work. Hard to imagine using GoTo on a table.

Typically the tube alone sells for around $90 in the classifieds so that is a good price if the motors still work.

Personally for GNG I would want something with a wider view so I don’t have to spend ten minutes of a short session doing a GoTo alignment. But I have taken my ETX 90 (and tripod) out for quick looks at the Moon and planets.

Scott 

 

I have the RA, the manual version with the clock drive. Rock steady on a table and gives great views.


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#12 SeattleScott

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Posted 21 January 2020 - 12:19 PM

I have the RA, the manual version with the clock drive. Rock steady on a table and gives great views.

So you have the little tripod legs. Good to know those work well for table top.

Scott
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#13 Augustus

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Posted 21 January 2020 - 12:43 PM

So you have the little tripod legs. Good to know those work well for table top.

Scott

Yeah, they are great.



#14 wrnchhead

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Posted 21 January 2020 - 01:10 PM

Augustus I have the same scope, well my friend has it now, but what do you do about looking at something overhead?
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#15 Augustus

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Posted 21 January 2020 - 01:24 PM

Augustus I have the same scope, well my friend has it now, but what do you do about looking at something overhead?

You basically can't look at anything near or north of the zenith because it's impossible to look through the finder, and this is true on a tripod as well with the ETX RA. I upgraded to a right-angle finder which is slightly better but north of the zenith is still hard. 

 

It's really a scope for the moon, planets, and doubles anyways so I don't much care. If I want a travel/G&G scope for DSOs I bring the SkyScanner.


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#16 wrnchhead

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Posted 21 January 2020 - 01:30 PM

Ok good your conclusions match mine. He lives two blocks from Central Park in NY, so it was never going to be a DSO scope or anything. Excited for planet season to get here! 


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#17 jgraham

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Posted 21 January 2020 - 04:07 PM

I have both the RA and GoTo versions of the ETX-90 and as others have noted it works fine as a tabletop scope. I have added a Vixen mount to nearly all of my scopes so that I can attach either a 30mm or a 50mm RACI finder, including my ETX-90s. This makes star-hopping a joy with these scopes. With the GoTo versions I use the hand controller to move the scope while looking through the finder. It is a lot of fun being able to freely move between using the GoTo and star-hopping. :)

Enjoy!
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