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Celestron 4" Mak rear cell?

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#1 mattyfatz

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Posted 02 October 2014 - 12:05 PM

Hi all,

the Celestron 4" Mak, has a rear threaded male cell. This cell is different from the threads on an ETX.

The model I have is the orange tube from the Next Star package.

1. Has anyone used this cell to attach accessories?

2. Is there an adapter to match SCT type visual backs?

3. Has anyone used this cell to turn the scope into a spotter?

 

thanks!

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#2 mattyfatz

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Posted 02 October 2014 - 12:05 PM

Sorry that pic is so dark....



#3 Jan Owen

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Posted 02 October 2014 - 12:45 PM

Hi all,

the Celestron 4" Mak, has a rear threaded male cell. This cell is different from the threads on an ETX.

The model I have is the orange tube from the Next Star package.

1. Has anyone used this cell to attach accessories?

2. Is there an adapter to match SCT type visual backs?

3. Has anyone used this cell to turn the scope into a spotter?

 

thanks!

Not sure if this'll work (4" is neither 90 mm nor 127 mm), but it looks like it might, if for no other reason than it fits the other two...  The best idea is probably to give SS a call; Jim's very helpful...

http://scopestuff.com/ss_smsa.htm


Edited by Jan Owen, 02 October 2014 - 12:53 PM.


#4 mattyfatz

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Posted 02 October 2014 - 01:00 PM

Thanks Jan,

I'll call Jim at SS and ask about that one. I was thinking I needed a "go between" adapter.

I'm going to try and use a focal reducer with this scope using that rear port.



#5 Jan Owen

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Posted 02 October 2014 - 05:59 PM

Thanks Jan,

I'll call Jim at SS and ask about that one. I was thinking I needed a "go between" adapter.

I'm going to try and use a focal reducer with this scope using that rear port.

 

 

Another alternative worth checking; Agena Astro carries a wide variety of different types of adapters, and they're also very helpful...

 

http://agenaastro.co...s/adapters.html


Edited by Jan Owen, 02 October 2014 - 06:02 PM.


#6 mattyfatz

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Posted 04 October 2014 - 11:35 AM

After a little research I discovered that the rear cell threads on this scope are the same across the Celestron Maksutov line.

the C90, NexStar 4, and 127mm Mak, all have 44.5 mm threads.

The Scopestuff SMSA serves the purpose. 



#7 Geo.

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Posted 08 October 2014 - 10:13 AM

You will find that these threads are a legacy from the accessories sold in the '70s and '80s by both Celestron and Meade. The visual backs sold with the SCTs had these 1.38" * 24TPI (35mm) and a variety of accessories use them. This is also the rear port thread on the original C90. There was an accessory sold for the C90 called the Large Accessory Ring (LAR) that permitted the use of the SCT visual back and other 2-24TPI accessories. The last LAR I saw go at auction brought over $80!!

 

Don't confuse the 127Mak with the 130. The 127 is an Orion Apex 127 in Celestron clothing. I assume the 90/102 (N4) and 130 were sourced by Synta from another OEM. The Apex 127 ring will fit the 127 Mak, but not the 90/102 (N4) and 130 with integral visual back flip mirror.

 

Meade sells a LAR (ETX - SCT Thread Adaptor #07036) for the ETX90/105/125, which has a SIMILAR rear port thread for about $20. However the ETX rear port is 34.6 mm and the #07036 is a bit tight on the 35 mm Celestron rear port. With some lapping it can be made to fit. Getting it back off is another issue.

 

The Baader NX4/C90 / ETX / SCT adapter, Part 2958500A is like the LAR, but it adds a 1.25" filter thread, so you can screw your filter in and use it with this adapter. It only seems to be sold with s female SCT thread to male T-thread adapter for about $40. Notice that they sell this for the ETX too. The Celestron 35mm will fit the Meade 34.6mm as the thread pitch is the same.

 

The ScopeStuff #ETXA - ETX Rear Cell Thread Adapter is similar to the Meade #07036, $31.


Edited by Geo., 08 October 2014 - 10:23 AM.


#8 mattyfatz

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Posted 08 October 2014 - 11:55 PM

Thanks for this post. Good info here. The Meade 0736 adapter does not fit the celestron c90, or the nexstar4.. I've tried.
The LAR will fit the Celestron 130 since the rear thread cell is the same as the other two Maks.
The Baader unit looks like a nice product, but I haven't seen it yet.

#9 rcooley

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Posted 05 November 2014 - 08:12 PM

On my 4SE I used a Baader NX4-ETX Universal Adapter # 2958500 and a Celestron visual back (Celestron # 93653A) both purchased from Agena Astro, and then attached a Williams Optics correct image prism diagonal (which I like a lot).  In my case I only used the "A" half of the baader adapter and then attached the visual back to that.   On my particular scope the baader threads only screwed on about a third of the way, but it was enough to make a secure fit for visual use.  I chalked this up to thread tolerances, but it might problematic for everyone.  Nevertheless, this rig is not necessary for attaching a DSLR as the camera adapter itself threaded onto the back of the SCT perfectly.  

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#10 Chassetter

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Posted 06 November 2014 - 07:16 PM

On my 4SE I used a Baader NX4-ETX Universal Adapter # 2958500 and a Celestron visual back (Celestron # 93653A) both purchased from Agena Astro, and then attached a Williams Optics correct image prism diagonal (which I like a lot).  In my case I only used the "A" half of the baader adapter and then attached the visual back to that.   On my particular scope the baader threads only screwed on about a third of the way, but it was enough to make a secure fit for visual use.  I chalked this up to thread tolerances, but it might problematic for everyone.  Nevertheless, this rig is not necessary for attaching a DSLR as the camera adapter itself threaded onto the back of the SCT perfectly.  

That is the same set up I went with, except my Baader adapter threads in fine. I chose a GSO correct image prism diagonal and a Baader zoom for the eyepiece. In the flip mirror diagonal I put a 6mm TMB Optical Planetary for high power. Still have to set my parfocal ring to it  to match the zoom at highest power (don't know if it will). Ialso got rid of the stock finder and put a Baader 50mm SkySurfer V red dot finder.




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