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dismantling ETX70

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#1 nytecam

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Posted 16 January 2007 - 06:55 AM

...ok I've taken the plunge :grin: Prior to sorting the disfunctional drive system I want to use the optical system piggyback on my LX200. These are progress pics...the cap, locking lever, axial bolt and washers removed [right but kept in order!] and the base removed from the RA/Azimuth shaft [centre and left]. Three Philips screws removed to release the non-driven Dec/Altitude fork. Unscrew the two Dec/Altitude knobs to release the optical tube.

I'm agreeably pleased with the ingenious interior design of the ETX but don't do what I've done unless you understand any Meade warrantee will be void :tonofbricks:

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  • 1364241-etx70b.jpg


#2 nytecam

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Posted 16 January 2007 - 06:57 AM

...with fork removed to release 'scope :rainbow:

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  • 1364242-etx70a.jpg


#3 Kenny2004

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Posted 16 January 2007 - 09:32 AM

Thanks for sharing such great pictures of a gutted ETX. :)

I'm curious to know about the mount of the ETX to the LX200 - please share just as well when you get to that part :) Thx.

#4 rodelaet

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Posted 17 January 2007 - 05:00 AM

Nice pics, Maurice.

I would like to know if the Dec's axis with gear can be removed from the OTA, to get a 'clean' OTA? I'm thinking of mounting my ETX 70 on my ETX 105. If you manage, can you tell me the weight from the OTA with only the 90° EP holder, please?

#5 Rainbow

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Posted 17 January 2007 - 08:24 AM

Excellent information

#6 nytecam

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Posted 17 January 2007 - 12:19 PM

Nice pics, Maurice. I would like to know if the Dec's axis with gear can be removed from the OTA, to get a 'clean' OTA? I'm thinking of mounting my ETX 70 on my ETX 105. If you manage, can you tell me the weight from the OTA with only the 90° EP holder, please?

Many thanks for your interest. The flanges supporting the Dec axis seem an integral part of the rear housing incorporating flip-mirror and rear port and probable epoxy welded in place and may need surgery to remove. :bawling: There's a single Philips screw to each flange but only for forward location of the rear housing to the main tube.

The ETX70 OTA alone [including Dec axes/flanges] weighs 1kg [=2lb 4oz] and the balance point is 95mm OG side of the Dec axis. With my Canon 300D DSLR [750gm] attached via T-ring and 32mm Plossl [150gm] in the flip-mirror box the balance point is close to or on the Dec axis! I suspect if the Dec axes were sawn off :tonofbricks: changes in overall weight and balance point would be minimal which is why I'll be leaving them in place.

Hope that helps clarify :rainbow:

#7 rodelaet

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Posted 17 January 2007 - 01:55 PM

Maurice,

Thank you so much for the info!! :thanx: I guess it's feasable to balance the ETX 105 with the ETX 70 on top.

#8 rodelaet

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Posted 17 January 2007 - 05:29 PM

I just cleared my ETX from its mount. That was the easy part. Now comes the next issue : how to piggyback it on my 105 :confused: :question:

#9 nytecam

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Posted 18 January 2007 - 02:52 AM

I just cleared my ETX from its mount. That was the easy part. Now comes the next issue : how to piggyback it on my 105

Keep us posted - I need to do the same for my piggyback to LX200 :lol: Here's the ETX coupled to my DSLR :rainbow:

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  • 1368254-etx_dslr.jpg


#10 AstronomyXtreme

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Posted 18 January 2007 - 12:25 PM

Ah, I always wondered what was there!

Would it be possible to take the 70 OTA off and replace it with a ST80 or WO 66ED?

#11 nytecam

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Posted 18 January 2007 - 04:50 PM

Would it be possible to take the 70 OTA off and replace it with a ST80 or WO 66ED?

Pass :grin: but this is a full-frame test pic taken this evening in poorish transparency in 30sec exposure using the ETX-70 OTA as above piggybacked on LX200. :rainbow: There's coma + astigmatism evident in the corners of the DSLR 23mm x 15mm sensor but it's surprisingly good for such a simple two-element 70mm aperture f/5 achromat against regular Canon lenses costing megabucks :lol: OK - I've removed the hideous LP hereabouts and tweaked contrast and sharpness a little :smirk:

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  • 1369276-m45etx070118z.jpg


#12 stefsaber

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Posted 18 January 2007 - 06:12 PM

Wicked...

I'd really enjoy seeing a shot of M42 through that contraption! ;)

Glad to see you were able to take apart the etx!

#13 NorthCoast

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Posted 20 January 2007 - 12:08 AM

nytecam,

Do you have any pics of the ETX-70 on you LX-200? :)

Second question, did you guide with the LX-200 or just let it track unguided?

#14 nytecam

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Posted 20 January 2007 - 03:39 AM

Do you have any pics of the ETX-70 on you LX-200? :)
Second question, did you guide with the LX-200 or just let it track unguided?

Thanks for the interest. For this quick test the ETX70+Canon DSLR combo temporarily supported via the camera's tripod bush [not really recommended!] onto the LX200 camera bracket - may do pic sometime. No guiding necessary for modest 350mm fl and 30s exposure. The LX200 is equatorially mounted and I regularly use 35-300mm [not zoom] lenses in this mode unguided onto DSLR.

When better and adjustably supported, I intend the ETX to serve a dual role of larger finder for the LX200 eg relaxed viewing downwards via the flip mirror and as a camera lens via the rear port as these experiments. Hope that clarifies :rainbow:

#15 mattyfatz

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Posted 20 January 2007 - 04:51 PM

This is great stuff. I'm trying to figure out if my 100mm sct will fit in the ETX 70 mount. This thread is very helpful.
Matty

#16 shorty101

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Posted 04 February 2007 - 01:31 PM

how did you mount it??? ive got a etx70 too, and i want to mount it ontop of my orion spaceprobe pics please!

#17 nytecam

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Posted 04 February 2007 - 02:29 PM

how did you mount it??? ive got a etx70 too, and i want to mount it ontop of my orion spaceprobe pics please!

Haven't advanced beyond my msg #1372285 dated 07/01/20 08:39 AM above - as yet :rainbow:

#18 seeker372011

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Posted 05 February 2007 - 04:50 AM

now that I have recovered from the shock :scared: :scared: of seeing these mutilated ETX 70s I have to say this is a most interesting thread-thanks for sharing and watching with interest

#19 nytecam

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Posted 05 February 2007 - 05:31 AM

now that I have recovered from the shock :scared: :scared: of seeing these mutilated ETX 70s I have to say this is a most interesting thread-thanks for sharing and watching with interest

Thanks Seeker - I'm even grateful for my own photos for get the washers and shims back in the right order :roflmao:

#20 mattyfatz

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Posted 07 August 2007 - 04:07 PM

Nytecam,
I have unscrewed every possible screw and nut but I cant get the base off. How did you do it!

#21 ukcanuck

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Posted 07 August 2007 - 04:49 PM

There's one screw that you may be overlooking, as it can hide in plain sight...it's the big one on the top right of the picture at the top of this thread (it's black there, although the ones I've seen have been white). It's made of some kind of nylon/plastic and it sits right in the middle on the main bolt.

Richard

#22 mattyfatz

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Posted 07 August 2007 - 05:44 PM

Thanks richard.
It is there but its on so tight I did'nt realize it was a bolt. I'll get the buggar of now!

#23 Talstarone

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Posted 07 August 2007 - 06:44 PM

Thank You all for bringing this thread back to the cover page. It will certainly serve as a great asset to all who own an ETX in both troubleshooting any problems they may have. And also a way to repair any gears or other pieces that may need to be worked on.

#24 mattyfatz

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Posted 07 August 2007 - 09:33 PM

I will sure keep you all posted on my progress. I’m taking it apart to fix a sheared declination knob. When its all apart I may try putting another optical tube on the ETX mount. I have a Criterion 4000 tube, a Meade 102mm SCT, and a C90. It may take some work but I think I can pull it off. If not I’ll convert the ETX70 tube into a spotting scope.
Here are two other links that helped me out.

http://www.schlatter...etx90decknb.htm
http://www.weasner.c...e/70atguide.htm

#25 mattyfatz

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Posted 08 August 2007 - 08:53 PM

Well...
The Criterion and the Meade102 will not fit withoout a major modification. The two forks are not wide enough apart. The right fork has nothing to do with the drive system though, so there might me something I can do with that.


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