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So I bought a Orion 9x50 RACI for my XT8 just to try it out and...

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#1 James1996

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Posted 24 July 2021 - 05:42 PM

The thing just slid right out of the finderscope bracket! I barely even touched the thing with my face and it just slid right out and down the tube into solid concrete! At least it didn't break... though apparently the finderscope bracket cant hold something so "heavy"! Guess what happend when I tried to do more then hand tighten the thumbscrew so the thing would actually hold the RACI? The screw head snapped off is what happened! So apparently the finderscope bracket is utterly useless for much more then the stock Red Dot Finder... At least that's my experience. bangbang.gif

 

Fortunately I was able to get the Red Dot Finder back into the bracket and stay in it even with the broken screw that I now cant get out of the bracket. Lets hope the finderscope bracket I ordered for my AT80ED actually works as it should and it can handle the RACI without it sliding right out of the bracket! bangbang.gif


Edited by James1996, 25 July 2021 - 12:02 AM.


#2 Jon Isaacs

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Posted 24 July 2021 - 06:09 PM

I'm not sure what exactly happened.. you should be able to extract the broken off screw and replace it.

 

There is some variability been the different finder's shoes and dovetails.  Worst comes to worst you could drill and tap a new hole that was better positioned.

 

Jon



#3 James1996

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Posted 24 July 2021 - 07:22 PM

I'm not sure what exactly happened.. you should be able to extract the broken off screw and replace it.

 

There is some variability been the different finder's shoes and dovetails.  Worst comes to worst you could drill and tap a new hole that was better positioned.

 

Jon

Don't know how to do first one, as for the second one I sadly don't have the power tools necessary to drill & tap a new hole in the finderscope bracket. sigh2.gif I'm starting to think about just removing the finderscope bracket altogether & putting a Telrad or a Rigel Quick Finder in it's place. I can still try out the RACI on my AT80ED when I eventually get it up & running, still waiting for my AZ5 mount to arrive to put it on...
 


Edited by James1996, 24 July 2021 - 07:25 PM.


#4 Diego

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Posted 24 July 2021 - 07:24 PM

I modify all my equipment to have an extra safety feature. I don't trust hand tightened set screws like those used on vixen dovetails to secure an OTA.

I usually find a way to drill a hole and pass a screw though both parts. You never know if you could forget to tighten a set screw and down comes the optics to meet the ground.

For my 9x50 finder, I went with the previous approach. The set screw goes through the finder bracket so even if the screw may be loose, it won't fall down

#5 mikemarotta

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Posted 24 July 2021 - 08:03 PM

The thing just slid right out of the finderscope bracket!

I am sorry for your loss. Reports like this do come up every now and then. It is hard to know what you could have done differently. I am not a mechanical person myself, but owning a telescope - now having owned and still now owning several - made me a real fan of the Fasteners aisle at Home Depot.

 

Second Fix4 copy 2.jpg

 

I glued the beer bottle cap on the screw head so that I would know it in the dark after I read of someone else having their reflector hit the deck when they turned the wrong screw.


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#6 kfiscus

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Posted 24 July 2021 - 08:13 PM

Something is definitely not right.  The brackets are strong enough.  It sounds like a mis-threaded set screw.  If you are the original owner, Orion will ship you a replacement base.  If you stargaze with others, somebody might have an extra base on hand.  (I have 4...)



#7 Orion68

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Posted 24 July 2021 - 09:50 PM

So sorry this happened to you. 

 

A good reminder to us all to check our set screws because they will work loose from time to time.

 

Good luck.



#8 firemachine69

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Posted 24 July 2021 - 10:39 PM

Screw in the finder into the base. Screw it tight to make an indent. Remove bracket from base. Drill a slight divot where the screw left a mark. 


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#9 Jon Isaacs

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Posted 25 July 2021 - 10:37 AM

Screw in the finder into the base. Screw it tight to make an indent. Remove bracket from base. Drill a slight divot where the screw left a mark. 

This works nicely but you need a drill. 

 

Another option is to purchase another base. I bought a couple of these recently.  They have 4 cross slots so they will fit any existing holes and they have dual thumb screws so they are extra secure.  And they are in stock.

 

https://agenaastro.c...nder-xfurb.html

 

Jon


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#10 Starman1

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Posted 25 July 2021 - 02:28 PM

The thing just slid right out of the finderscope bracket! I barely even touched the thing with my face and it just slid right out and down the tube into solid concrete! At least it didn't break... though apparently the finderscope bracket cant hold something so "heavy"! Guess what happend when I tried to do more then hand tighten the thumbscrew so the thing would actually hold the RACI? The screw head snapped off is what happened! So apparently the finderscope bracket is utterly useless for much more then the stock Red Dot Finder... At least that's my experience. bangbang.gif

 

Fortunately I was able to get the Red Dot Finder back into the bracket and stay in it even with the broken screw that I now cant get out of the bracket. Lets hope the finderscope bracket I ordered for my AT80ED actually works as it should and it can handle the RACI without it sliding right out of the bracket! bangbang.gif

On most scopes, the finder bracket and shoes are installed upside down, so the finder slides out toward the bottom of the scope.

One of the modifications I used to make on every scope I sold, years ago, was to turn the bracket around, re-mount the shoe in the other direction and slide the finder into the bracket pointing the other direction.

ALL finder brackets should slide out of their shoes toward the TOP of the scope, not the bottom.

Had this been a truss scope, it could have landed on the mirror.


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#11 Echolight

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Posted 25 July 2021 - 05:39 PM

That’s terrible! 
 

I always set my scope up on the grass. Because I can be very clumsy and knock over eyepieces and binoculars.



#12 Jon Isaacs

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Posted 25 July 2021 - 06:24 PM

On most scopes, the finder bracket and shoes are installed upside down, so the finder slides out toward the bottom of the scope.

One of the modifications I used to make on every scope I sold, years ago, was to turn the bracket around, re-mount the shoe in the other direction and slide the finder into the bracket pointing the other direction.

ALL finder brackets should slide out of their shoes toward the TOP of the scope, not the bottom.

Had this been a truss scope, it could have landed on the mirror.

 

That works to some extent with a Dob though the grooves in a Synta finder do not line up properly with the finder bracket.

 

The reason the dovetails are the way they are is that the finder's were originally meant for refractors with the shoe cast into the focuser. Theyre still making the refractors that way so the finder's to fit the refractors.

 

You can purchase a bracket that's a better fit.. this will fit your Orion finder and can fit fitted with a stop bolt to keep it from sliding out of the finder shoe?

 

https://agenaastro.c...base-dfb50.html

 

Jon



#13 James1996

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Posted 25 July 2021 - 07:04 PM

This works nicely but you need a drill. 

 

Another option is to purchase another base. I bought a couple of these recently.  They have 4 cross slots so they will fit any existing holes and they have dual thumb screws so they are extra secure.  And they are in stock.

 

https://agenaastro.c...nder-xfurb.html

 

Jon

I just bought two of them, one for my XT8 & one for my AT80ED.


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#14 NYJohn S

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Posted 25 July 2021 - 07:06 PM

The Orion finder has a piece on the back that hangs down so it can’t be slid in from the front of the base. You really should have a base with a notch cut out of the back although it slides in far enough to to hold without the notch. 

 

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#15 Starman1

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Posted 25 July 2021 - 07:30 PM

The Orion finder has a piece on the back that hangs down so it can’t be slid in from the front of the base. You really should have a base with a notch cut out of the back although it slides in far enough to to hold without the notch. 

Sure it can:

1) reverse the shoe (base) on the scope.

2) remove finder from bracket and reinstall in bracket pointed the other way.

3) reinstall finder with bracket sliding in from the top instead of the bottom.


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#16 NYJohn S

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Posted 26 July 2021 - 07:17 AM

Sure it can:

1) reverse the shoe (base) on the scope.

2) remove finder from bracket and reinstall in bracket pointed the other way.

3) reinstall finder with bracket sliding in from the top instead of the bottom.

It doesn't just slide out of the bracket but you're right. I just checked and you can unscrew the front of the finder and then it will come out without the front objective and focus lock ring. 

 

Btw, to the OP. This is the base that has the notch for the finder. Unfortunately I have no idea where I got it. The other base will work but it won't slide in all the way. It's still enough to hold it securely. I have one like that on one of my refractors.

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#17 Jon Isaacs

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Posted 26 July 2021 - 09:25 AM

Sure it can:

1) reverse the shoe (base) on the scope.

2) remove finder from bracket and reinstall in bracket pointed the other way.

3) reinstall finder with bracket sliding in from the top instead of the bottom.

 

In my experience, installing the finder in the bracket backwards is pretty flaky, the grooves for the Oring and thumbscrews are very different..

 

Jon



#18 Starman1

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Posted 26 July 2021 - 10:54 AM

In my experience, installing the finder in the bracket backwards is pretty flaky, the grooves for the Oring and thumbscrews are very different..

 

Jon

Jon,

I've done it lots of times.  It works OK.

It's not the optimum bracket for a finder, anyway, since an O-ring only lasts a couple years at most.

I prefer a bracket with 2 rings and 6 adjustment screws.



#19 Jon Isaacs

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Posted 26 July 2021 - 12:32 PM

Jon,

I've done it lots of times.  It works OK.

It's not the optimum bracket for a finder, anyway, since an O-ring only lasts a couple years at most.

I prefer a bracket with 2 rings and 6 adjustment screws.

The problem is that the O-ring is meant to fit in the narrow groove and the thumbscrews in the wide groove, that holds everything aligned.  

 

Reversing them puts the O-ring in the wide groove so it doesn't hold the finder and the thumbscrews are too wide for the narrow groove so they don't really hold the finder in place. I just use the finders normally and make sure the thumb screw is tight. And if I am worried, then I drill the base so the thumbscrew rides in a divot.   It does work with the finder backwards but it's less than ideal. 

 

The main problem with these finders is the two screws and a spring alignment system, the finders can shift.  What I have done is drill and tap a hole next to the spring assembly and then use the third screw to lock the finder in place. 

 

These days, I use finders that take 1.25 inch eyepieces and 6 screws for adjustment.  

 

StellarVue finder on 22 inch.jpg

 

Jon


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#20 Ihtegla Sar

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Posted 26 July 2021 - 12:44 PM

The Orion finder has a piece on the back that hangs down so it can’t be slid in from the front of the base. You really should have a base with a notch cut out of the back although it slides in far enough to to hold without the notch.


Or, grind off the notch. That's what I did with my GSO finder that has the same base with the useless notch. What's wrong with sliding in a finder from the front? Seems like a useless notch to me.

A notch on the front so it doesn't slide out the back if the thumb screw inadvertently came loose would make a lot more sense.

The notch was getting in the way of me being able to use the GSO finder on my Classic Obsession with the shoe Jon linked, so I got rid of it. Seems to work fine without the notch.

#21 aeajr

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Posted 26 July 2021 - 04:26 PM

The thing just slid right out of the finderscope bracket! I barely even touched the thing with my face and it just slid right out and down the tube into solid concrete! At least it didn't break... though apparently the finderscope bracket cant hold something so "heavy"! Guess what happend when I tried to do more then hand tighten the thumbscrew so the thing would actually hold the RACI? The screw head snapped off is what happened! So apparently the finderscope bracket is utterly useless for much more then the stock Red Dot Finder... At least that's my experience. bangbang.gif

 

Fortunately I was able to get the Red Dot Finder back into the bracket and stay in it even with the broken screw that I now cant get out of the bracket. Lets hope the finderscope bracket I ordered for my AT80ED actually works as it should and it can handle the RACI without it sliding right out of the bracket! bangbang.gif

I used an Orion 9X50 RACI on my XT8. No problems. 

 

I also used it in a dual finder bracket with a laser finder.  The shoe handled it just fine.

https://www.telescop...et/p/102788.uts

 

 

I also used it with a dual finder barcket for the 9X50 RACI combined with a RDF. This is an outstanding combination.   Add a low power wide view, like the Q70 32 mm or 38 mm 2" eyepiece, and you have an awesome finder set. 

 

 

Sounds like you just over tightened the screw. 

Attached Thumbnails

  • Dual Finder RDF and 9X50 RACI (640x480).jpg
  • Dual Finder laser and 9X50 RACI.jpg

Edited by aeajr, 26 July 2021 - 04:37 PM.


#22 Jon Isaacs

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Posted 26 July 2021 - 05:55 PM

Or, grind off the notch. That's what I did with my GSO finder that has the same base with the useless notch. What's wrong with sliding in a finder from the front? Seems like a useless notch to me.

A notch on the front so it doesn't slide out the back if the thumb screw inadvertently came loose would make a lot more sense.

The notch was getting in the way of me being able to use the GSO finder on my Classic Obsession with the shoe Jon linked, so I got rid of it. Seems to work fine without the notch.

 

 

What Don is suggesting is to reverse the shoe on the scope and the reverse the finder in the bracket.  That way the finder is inserted from the top and the tab on the bracket prevents the finder from slipping and falling, potentially damaging the mirror.

 

As a matter of fact, within the last year, my GSO finder slipped out the dovetail shoe in my 120mm Eon, hit the concrete floor and broke off the plastic finder eyepiece.  If I had had the finder mounted the way Don had suggested, it couldn't have slipped out.  

 

I have done that in the past but pretty much stopped doing it because the finder moves around a bit.

 

I was able to jury rig an eyepiece for the GSO finder but it's a 25 mm so the exit pupil is large ad the magnification quite low.  I estimate it at 6x-7x, pretty low for a 50mm finder. 

 

Jon



#23 Ihtegla Sar

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Posted 26 July 2021 - 07:15 PM

What Don is suggesting is to reverse the shoe on the scope and the reverse the finder in the bracket. That way the finder is inserted from the top and the tab on the bracket prevents the finder from slipping and falling, potentially damaging the mirror.

As a matter of fact, within the last year, my GSO finder slipped out the dovetail shoe in my 120mm Eon, hit the concrete floor and broke off the plastic finder eyepiece. If I had had the finder mounted the way Don had suggested, it couldn't have slipped out.

I have done that in the past but pretty much stopped doing it because the finder moves around a bit.

I was able to jury rig an eyepiece for the GSO finder but it's a 25 mm so the exit pupil is large ad the magnification quite low. I estimate it at 6x-7x, pretty low for a 50mm finder.

Jon

I still don't understand why the manufacturers ever started putting a notch in the back. Even if they were originally designed for refractors, I don't understand how having a notch in the back provides any benefit in a refractor.

Reversing the finder in the bracket so you could slide the bracket into the shoe from the front would better protect the mirror but it doesn't seem like the finder would fit very well in the bracket backwards. I haven't tried it though and I will take Don's word for it that it works.

My plan is to replace the GSO with a Stellervue that I have on hand but haven't gotten around to setting it up. The Stellarvue bracket is one of those 6 screw brackets like that Agena you linked, and it looks like there are machine screw holes in the bottom on both ends. So if I can find a machine screw with the right threads, I could put a screw on the front end of the bottom of the bracket. That would let me load the finder into the shoe from the front and have a screw sticking down to act as a stop to protect the mirror. It would also give me a much better quality finder. The GSO finders are serviceable, and work well for the price but the Stellervue finder seems to be of much higher optical quality. And I have some 1.25 nebula filters I want to try out with the finder to see what I can see in a small widefield finder as a companion to the bug dob.

Edited by Ihtegla Sar, 27 July 2021 - 12:33 AM.


#24 ram812

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Posted 26 July 2021 - 07:21 PM

It doesn't just slide out of the bracket but you're right. I just checked and you can unscrew the front of the finder and then it will come out without the front objective and focus lock ring.

Btw, to the OP. This is the base that has the notch for the finder. Unfortunately I have no idea where I got it. The other base will work but it won't slide in all the way. It's still enough to hold it securely. I have one like that on one of my refractors.


Looks like what's on my AT6RC.

#25 Jon Isaacs

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Posted 27 July 2021 - 02:50 AM

I still don't understand why the manufacturers ever started putting a notch in the back. Even if they were originally designed for refractors, I don't understand how having a notch in the back provides any benefit in a refractor.

Reversing the finder in the bracket so you could slide the bracket into the shoe from the front would better protect the mirror but it doesn't seem like the finder would fit very well in the bracket backwards. I haven't tried it though and I will take Don's word for it that it works.

My plan is to replace the GSO with a Stellervue that I have on hand but haven't gotten around to setting it up. The Stellarvue bracket is one of those 6 screw brackets like that Agena you linked, and it looks like there are machine screw holes in the bottom on both ends. So if I can find a machine screw with the right threads, I could put a screw on the front end of the bottom of the bracket. That would let me load the finder into the shoe from the front and have a screw sticking down to act as a stop to protect the mirror. It would also give me a much better quality finder. The GSO finders are serviceable, and work well for the price but the Stellervue finder seems to be of much higher optical quality. And I have some 1.25 nebula filters I want to try out with the finder to see what I can see in a small widefield finder as a companion to the bug dob.

 

Don's scheme works but it's not ideal.. 

 

I have a 50 mm StellarVue finder.  It's a good finder but I would not say the optical quality is all that high.  Much better optically is the Astro-Tech 50mm RACI finder.  I was able to split Porrima with mine.  The StellarVue has issues at higher magnifications.  

 

But the StellarVue is plenty good enough for a finder and is F/4 rather than F/5 and more compact than the Astro-Tech and provides a wider field of view with the same eyepiece.

 

Jon




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