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Finder scope for Orion 120ST f/5

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#1 mark david

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Posted 11 September 2019 - 02:12 PM

I just received my Orion 120ST and a very nice TwiLIght 1 mount and tripod.

Until now I've always used my dob reflector.

On that it's quite easy to mount any kind and number of findersopes and a Telrad Reflex Finder Sight.

I would like to use both a RACI findersope and a reflex finder sight with my 120.

The built in bracket for a dovetail appears rather close to where a head would be if viewing.

Orion sells a duel findersope mount that fits into the bracket.  

My concern is that when I lean close to look thru the diagonal my head will hit the tail end of both finders.

And maybe it's just an illusion and it will be fine.

Please pardon the wordiness of this post.  
I'm not quite sure how to articulate it.

Any advice would be much appreciated.

I'd like to cover my bases before I purchase.

 

Thank you all.   

Mark41FAD9AHG5L._SX425_.jpg



#2 Mitrovarr

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Posted 11 September 2019 - 02:14 PM

If your diagonal interferes with your finder, simply rotate it.

#3 IMB

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Posted 11 September 2019 - 03:02 PM

Please note that with a 30 mm eyepiece the scope will provide a true field of view of over 4 degrees. A red-dot finder alone might be enough.


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#4 ris242

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Posted 11 September 2019 - 03:28 PM

My finderscope is always higher.

I moved my bracket to the other side on my TS scope as I use my right eye, so even if I use short main eyepieces, I don't hit the finder scope.  Also moving it to the otherside helped cause the dovetail tightening knobs were in the view of the finder.

 

you could do the same thing by rotating your scope and have the finder on the right....[I don't know if you can move your shoe on your orion]....but your focuser would be on a strange angle........more upside down.

 

d5.jpg


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#5 terraclarke

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Posted 11 September 2019 - 03:56 PM

I’ve had a couple of them (none currently). Seriously, it IS a finderscope, just drop a low-power/wide-field eyepiece in it and you’re good to go.  In fact there’s a guy in my club that has a big dob and he uses one as its finder. If you really want a superb ‘finding aid” for it tho, a green laser pointer is the way to go. If you’ve worried about scaring the krap out of your neighbors that the War of the Worlds is starting, a simple red dot will do instead,- a Telrad matches its ‘bulk’ nicely. Have fun. They are lots of fun!


Edited by terraclarke, 11 September 2019 - 03:59 PM.

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#6 clearwaterdave

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Posted 11 September 2019 - 04:08 PM

My 102 has screws on both sides.,the stalk on the finder puts it out enough for me to not bump it.,not sure if your shoe is off to the side or right on top.,good luck.,

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#7 Jon Isaacs

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Posted 11 September 2019 - 08:30 PM

I agree with Terra and IMB, the scope itself is a finder.  A red dot is all that is necessary.  

 

Jon


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#8 turtle86

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Posted 11 September 2019 - 08:57 PM

Please note that with a 30 mm eyepiece the scope will provide a true field of view of over 4 degrees. A red-dot finder alone might be enough.

 

+1 I have an Orion ST 120 and I find that a red dot finder is all I need.  I mostly use it for wide-field views with a low-power eyepiece, but even with a medium power eyepiece most of the brighter DSO’s are easy enough to find.  


Edited by turtle86, 11 September 2019 - 08:58 PM.

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#9 Mitrovarr

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Posted 11 September 2019 - 09:01 PM

I'll be the outlier and say that I use a standard straight through 8x50 finder. Although I generally put the scope on a goto mount.

#10 LDW47

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Posted 11 September 2019 - 09:06 PM

I agree with Terra and IMB, the scope itself is a finder.  A red dot is all that is necessary.  

 

Jon

I agree that a low power ep in that scope and others creates as good a finder as you can get so fill me in, why would you even need a red dot finder, what advantage ? I tried that and in most cases it was just a hindrance if anything !



#11 turtle86

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Posted 11 September 2019 - 09:49 PM

I agree that a low power ep in that scope and others creates as good a finder as you can get so fill me in, why would you even need a red dot finder, what advantage ? I tried that and in most cases it was just a hindrance if anything !

 

 If I’m just sweeping the Summer Milky Way at low power with something like a 35 Pan, chances are I won’t bother with a red dot finder myself.  But if I want to find something like an open cluster, I’ll slap on the finder.


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#12 LDW47

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Posted 11 September 2019 - 10:16 PM

 If I’m just sweeping the Summer Milky Way at low power with something like a 35 Pan, chances are I won’t bother with a red dot finder myself.  But if I want to find something like an open cluster, I’ll slap on the finder.

If I am using my 2”, 50mm, 40mm or 30mm WA eps and I know where the object is I will find it very fast, if I know approximately where it is I will find it fast, if I don’t know where it is and if I have to consult star maps, or Sky Safari or what have you I will find it with the low power ep that I am using, once oriented with the sky and at that point slapping on the red dot or any of my right angle finders etc. won’t help me one bit more because as has been said the scope itself is a huge finder, as big as it gets ! Not arguing, not bragging but I haven’t had to use a finder for years and I have found some pretty isolated stuff ! I have one of those same scopes in the SW brand and lets make sure, I want to make sure the poster knows their capabilities without the use of a finder, even if they don’t have the same experience or maybe they do ? Not saying they shouldn’t get some sort of finder but with practice, with scanning the skies on those great nites, by referencing / orienting themselves using a myriad of information and forums like this, finders can be left behind very easily ! As long as they are aware because they can be a waste of time and $ ! Just one more way of doing it, of looking at it but it don’t mean I’m completely right, lol !



#13 Jon Isaacs

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Posted 12 September 2019 - 06:00 AM

I agree that a low power ep in that scope and others creates as good a finder as you can get so fill me in, why would you even need a red dot finder, what advantage ? I tried that and in most cases it was just a hindrance if anything !

One advantage of a finder, either an RACI or a red dot, with a short focal length scope like this is that if I am viewing objects at higher magnifications, I can avoid swapping back and forth between a low power finder eyepiece and the eyepiece I am using.  Since at higher magnifications, I will be using 1.25 inch eyepieces and at low powers 2 inch, the swap in non-trivial.  

 

And a red dot gets me oriented faster than just using a wide field eyepiece.  With a red dot, if I know where I want to point the scope, I can point it more accurately, more precisely, it saves me time. The scope itself is a large finder but it can use some help.. 

 

I use finders all the time but mostly with larger scopes. 

 

Jon


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#14 Astrodave

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Posted 12 September 2019 - 07:32 AM

Swapping eyepieces gets old fast in the dark. Also who wants to bend down on their knees to look through a straight finder or RDF? Certainly not me. Green laser pointers are perfect but when you live under class B airspace like me you have to be very aware of using them and then what your neighbors will think if they see it. I've pretty much abandoned all of them for a right angle finder which is easy to use and does not interfere with me at all. It's very easy to swap from eyepiece to RAF. I'd be lost without mine now. I even use one on my AT60ED so I don't have to keep swapping out eyepieces.


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#15 LDW47

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Posted 12 September 2019 - 07:48 AM

One advantage of a finder, either an RACI or a red dot, with a short focal length scope like this is that if I am viewing objects at higher magnifications, I can avoid swapping back and forth between a low power finder eyepiece and the eyepiece I am using.  Since at higher magnifications, I will be using 1.25 inch eyepieces and at low powers 2 inch, the swap in non-trivial.  

 

And a red dot gets me oriented faster than just using a wide field eyepiece.  With a red dot, if I know where I want to point the scope, I can point it more accurately, more precisely, it saves me time. The scope itself is a large finder but it can use some help.. 

 

I use finders all the time but mostly with larger scopes. 

 

Jon

You are correct about the switching back and forth, it is a bit of a disruption but you get used to it. The other thing I found with the red dot from my recollection was that under certain sky conditions the object you were looking for in a part of the sky and the surrounding references are hard to locate in the small aperture of the red dot, at least to me it was annoying. But I do have a couple of 60mm right angle finders that I haven’t used for years, maybe I will try them again, as to red dots of which I have several, no ! For instance even something like the Dumbbell Nebula surrounded by a vast number of stars is not a big problem to find just scanning with say my WO 40mm if you use certain markers that you have noted over the years and I doubt a red dot would pick it up any quicker, any easier, if at all !



#16 Binojunky

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Posted 12 September 2019 - 09:54 AM

I have this scope, bought as a OTA, just rings and a dovetail added, a Red Dot is all I use,D.


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#17 cygnus72

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Posted 12 September 2019 - 10:40 AM

I don't know why I decided to log in today. After all, it has been a *long* time since I posted anything. This post immediately caught my attention.

 

I own a 120ST and I think I speak from plenty of experience when I say the following:

 

1. Throw the stock viewfinder in the trash or give it away. It's very much like looking through a straw. It's practically worthless.

2. Don't waste time in finding another viewfinder to replace it. 

3. As others have said, get a red dot finder. 

4. Replace the stock focuser with a beefy 2" focuser. Get a good quality 2" diagonal to match. 

5. Enjoy your new scope.

 

In all sincerity, the 120ST is a great scope. But the goodies that Orion throws in with it only limit what the scope is capable of.


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#18 tomykay12

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Posted 12 September 2019 - 01:18 PM

Telrad and call it a day


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#19 mark david

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Posted 12 September 2019 - 03:15 PM

Tomykay,

I wish I could use my Telrad.

There's not enough room for the mounting bracket.

It won't fit between the rings,  

I could rig something up ... but at that point I'll just find another.

I'm considering getting an Orion EZ RDF.... but I've read some pretty funky reports about this problem or that.

Some similar that's reliable would be fine.

Thanks though.



#20 MGD

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Posted 12 September 2019 - 03:44 PM

Mark try putting your telrad out on the dewshield instead of on the focuser end. I did this on my 6 inch f8 refractor and it works great for me.

Mike



#21 mark david

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Posted 12 September 2019 - 03:52 PM

Mike... 

I tried that as well.

It hangs over by an inch.

A Telrad is the only reflex finder I've used thus far and I suspect I've been spoiled by it.

The Rigel gets great reviews but there are no screw holes for the mount... unless I'm missing something.



#22 Jon Isaacs

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Posted 12 September 2019 - 04:02 PM

Scopestuff sells an Vixen/Orion/Celestron/GSO adapter/mount for the Telrad. It includes the Telrad mounting bracket. 

 

http://www.scopestuff.com/ss_tell.htm

 

Here's a photo..

NP-101 Telrad CN.jpg

 

I only use it when I'm using the refractor as a remote finder and want to align Telrad views between two scopes.

 

Jon


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#23 Jim7728

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Posted 12 September 2019 - 05:09 PM

Mike... 

I tried that as well.

It hangs over by an inch.

A Telrad is the only reflex finder I've used thus far and I suspect I've been spoiled by it.

The Rigel gets great reviews but there are no screw holes for the mount... unless I'm missing something.

 

You can attach a platform  or upside down dovetail bar(which is what I think I did)  on top of the tube ring which are threaded for short  1/4" threaded machine screw, then stick the Telrad base on top of.

 

Similar to this:

http://www.astronomy...achmentid=28746

 

Did the same for a Quickfinder base, maybe drilled out hole a little bit for screwing on top of tube ring.

 

post-9064-14072452477588_thumb.jpg


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#24 tomykay12

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Posted 12 September 2019 - 07:02 PM

Tomykay,

I wish I could use my Telrad.

There's not enough room for the mounting bracket.

It won't fit between the rings,  

I could rig something up ... but at that point I'll just find another.

I'm considering getting an Orion EZ RDF.... but I've read some pretty funky reports about this problem or that.

Some similar that's reliable would be fine.

Thanks though.

On my Orion 100ED, I mounted a plate on top of the rings, and put the Telrad on that; it works great. I used a piece of clear acrylic, but anything would work, even a piece of wood. An added benefit is it moves the Telrad away from the scope, making it easier to look thru. It;s also a very handy handle when mounting or un mounting the scope.


Edited by tomykay12, 12 September 2019 - 07:03 PM.

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#25 dwmedic

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Posted 12 September 2019 - 07:16 PM

+1 for the telrad and telrad base from scopestuff.


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