73 replies to this topic

[MarkMittlesteadt]

What would you suggest as the best dual-ring mount for a 6x30 finder?  The diameter of the finder is about 34mm.  I have both 6x30 IE straight-throughs and RACI's. 

 

I know from experience that if the diameter of the rings is too narrow, sometimes there will not be enough slack to do an easy alignment.  On the other hand, if the rings are too large, I might have to find longer thumbscrews.  

 

This question is open to anyone.

 

Mike

Typically, even 1/8" spacing around the finder OTA gives you a lot more adjustment than you'd think. A little goes a long way. Look for a ring diameter that is anywhere from 1/8" to 1/4" bigger than the finder OTA (with 1/4" giving plenty of adjustment space without being overly large). 

[MarkMittlesteadt]

Mike:

 

I meant it's probably easier to make a short finder mount and do it cleanly that to cut down a stalk finder.

 

The rings can be plastic pipe cut to a short length. Drill and tap 6 holes. 

 

The finder stalk and finder Mark is using is old technology, it's been around more than 20 years. Finders have come quite a long way in those 20 years if one wants better stuff.

 

Jon

I've made my own rings out of PVC, drilled and tapped as you mentioned. Having used both, dual-ring three point holders and the simple O-ring, spring loaded holder, I much prefer the latter. I even considered making a PVC version of what I have and a custom built short stalk. 

 

One thing I do like about mounting my finder on my ADM dovetail saddle (instead of a standard, stationary findershoe) is I can slide it anywhere along the dovetail rail. I typically use my left eye at the eyepiece so the finder is close but not in my way. Those who use their right eye might be bumping into it, so I can just slide it higher up on the dovetail rail without losing alignment. So for me, it works out better than a permanent attachment location. 

 

Lots of different ways to go about it. 

Edited by MarkMittlesteadt, 06 August 2022 - 10:37 AM.

[MarkMittlesteadt]

I could hacksaw through a finder stalk.  If I did that, I might be stuck watching TV for an hour or more while I'm sawing.  Not the first time I've done something like that.  I don't like it, but I've done it.

 

How strong is JB weld?  I would be concerned that it might give way or at least develop weakness over time.  

 

But like Jon said, there are better finder mounts available now.  I doubt I'd spend any time shortening the stalk to an o-ring style finder mount.

 

Mike

There are many different grades and types of JB Weld products, including clear epoxy.

[Sarkikos]

Typically, even 1/8" spacing around the finder OTA gives you a lot more adjustment than you'd think. A little goes a long way. Look for a ring diameter that is anywhere from 1/8" to 1/4" bigger than the finder OTA (with 1/4" giving plenty of adjustment space without being overly large). 

The dual-ring mount that was designed for thin laser finders was marginal at best for a 6x30 finder.  IME, 1/8" is barely doable, and somewhat more than 1/4" of wiggle room is probably desirable.  I can't stand running out of room for a thumb screw to align a finder.  When the finder butts up against the inside of the ring or a screw won't tighten/loosen any more, you need more room for adjustment.  IME, if the rings are too narrow, this can easily happen even if you start out with all six screws adjusted to equal distances.

 

Mike

Edited by Sarkikos, 07 August 2022 - 06:40 AM.

[Sarkikos]

I've made my own rings out of PVC, drilled and tapped as you mentioned. Having used both, dual-ring three point holders and the simple O-ring, spring loaded holder, I much prefer the latter. I even considered making a PVC version of what I have and a custom built short stalk. 

 

One thing I do like about mounting my finder on my ADM dovetail saddle (instead of a standard, stationary findershoe) is I can slide it anywhere along the dovetail rail. I typically use my left eye at the eyepiece so the finder is close but not in my way. Those who use their right eye might be bumping into it, so I can just slide it higher up on the dovetail rail without losing alignment. So for me, it works out better than a permanent attachment location. 

 

Lots of different ways to go about it. 

I like having lots of different placement locations for Orion/Synta finder bases. 

 

For refractors, if the visual back has room and holes for a base on both sides of the focuser, I'll attach two bases.  If I can attach a base to one of the refractor rings, I'll do it. 

 

For Newts, I can drill a couple holes in the OTA to attach a finder base.  (It is a bother, though, to remove and reinstall the mirrors.)   If the Newt is in rings, I can attach a finder base to one of the rings.

 

Locations for finder bases on Cats is usually limited.  And I'm not about to open up a Cat to drill holes for a finder base.  But often you can attach a second finder base in pre-drilled holes on the back rim, at the opposite side of the focuser.  Even if it will be out of sight on the other side of the OTA, that's OK for laser finders.

 

If a mount for a telescope has a location I can attach a finder base so that the finder will move along with the telescope, I'll attach a base there.  Sometimes, if the mount has a panhandle, you can mount a finder base somewhere on the panhandle, maybe where it attaches to the mount by a screw.  You'll probably need a longer screw.

 

Of course, the unusual out-of-the-way locations for finder bases are meant for laser finders.  They can be located pretty much anywhere.  You just need to be able to reach your hand to them.

 

Just this morning I was looking around my scopes and mounts for more places to attach finder bases.  I found five, including one location on a p-gram for binoculars.  Looks like another order for ScopeStuff!     On second thought, I think I'll order the finder bases from AliExpress.  They are a lot cheaper there! 

 

Mike

Edited by Sarkikos, 06 August 2022 - 07:01 PM.

[Bill Barlow]

I use the current Meade finder scope mounting base and 50mm ring with Orion 9x50 RACI finder scopes.  The low profile of this finder setup is nice as the finder is very close to the OTA, no more than 1” above it.  The hole spacing on the Meade finder shoe is 32mm which exactly matches the hole spacing on the C5, C6, C8 and C9.25 OTA’s where the finder base attaches to the tube.  
 

I have one on my C11 but I had to drill out one of the mounting holes on the finder base to make it slightly wider.

 

Bill

Edited by Bill Barlow, 06 August 2022 - 11:55 AM.

[Sarkikos]

I use the current Meade finder scope mounting base and 50mm ring with Orion 9x50 RACI finder scopes.  The low profile of this finder setup is nice as the finder is very close to the OTA, no more than 1” above it.  The hole spacing on the Meade finder shoe is 32mm which exactly matches the hole spacing on the C5, C6, C8 and C9.25 OTA’s where the finder base attaches to the tube.  
 

I have one on my C11 but I had to drill out one of the mounting holes on the finder base to make it slightly wider.

 

Bill

Would you post a link to an example of the current Meade finder scope mounting base and 50mm ring?

 

Mike

[Second Time Around]

What would you suggest as the best dual-ring mount for a 6x30 finder?  The diameter of the finder is about 34mm.  I have both 6x30 IE straight-throughs and RACI's. 

 

I know from experience that if the diameter of the rings is too narrow, sometimes there will not be enough slack to do an easy alignment.  On the other hand, if the rings are too large, I might have to find longer thumbscrews.  

 

This question is open to anyone.

 

Mike

I'd suggest the 50mm size.  It's compatible with tube diameters of 20-50mm, so 34mm is almost slap bang in the middle.

 

I'd add that the screws on mine all have a total thread length of 20 mm.

[Jon Isaacs]

I've made my own rings out of PVC, drilled and tapped as you mentioned. Having used both, dual-ring three point holders and the simple O-ring, spring loaded holder, I much prefer the latter. I even considered making a PVC version of what I have and a custom built short stalk. 

 

One thing I do like about mounting my finder on my ADM dovetail saddle (instead of a standard, stationary findershoe) is I can slide it anywhere along the dovetail rail. I typically use my left eye at the eyepiece so the finder is close but not in my way. Those who use their right eye might be bumping into it, so I can just slide it higher up on the dovetail rail without losing alignment. So for me, it works out better than a permanent attachment location. 

 

Lots of different ways to go about it. 

 

The O-Ring spring finder mount only fits one finder.  The finder cannot be slid forward or rearward in the mount. The dovetail foot is fixed in the shoe, can't be slid. 

 

A single 2 ring six screw mount fits a variety of finders. The finder can be slid forward and backward in the rings and dovetail rail can be slid forward and backward in the dovetail shoe. That's a lot of flexibility.

 

The fact the the O-Ring-spring bracket only fits one finder type is the real deal killer. I would be stuck and have to use either the Orion 9x50 or the GSO 8x50 RACI finders. I wouldn't be able the use my SV-50 or Astro-Tech 50 mm RACI finders, these both use 1.25 nch eyepieces, have helical focusers and are in a different league optically. I also have 70 mm and 80 mm Finders. 

 

Once I bit the bullet  and started actually using 2 ring finders, I realized their advantages and discovered they were easier to adjust than I'd thought. 

 

Imagine a 50 mm F/5 RACI telescope with an Explore Scientific 20 mm 68° eyepiece and compare it in your mind to the Orion 9x50.. 

 

You can only use the former as a finder with a 2 ring mount. 

 

Jon

[Jim in PA]

The O-Ring spring finder mount only fits one finder.  The finder cannot be slid forward or rearward in the mount. The dovetail foot is fixed in the shoe, can't be slid. 

 

A single 2 ring six screw mount fits a variety of finders. The finder can be slid forward and backward in the rings and dovetail rail can be slid forward and backward in the dovetail shoe. That's a lot of flexibility.

 

The fact the the O-Ring-spring bracket only fits one finder type is the real deal killer. I would be stuck and have to use either the Orion 9x50 or the GSO 8x50 RACI finders. I wouldn't be able the use my SV-50 or Astro-Tech 50 mm RACI finders, these both use 1.25 nch eyepieces, have helical focusers and are in a different league optically. I also have 70 mm and 80 mm Finders. 

 

Once I bit the bullet  and started actually using 2 ring finders, I realized their advantages and discovered they were easier to adjust than I'd thought. 

 

Imagine a 50 mm F/5 RACI telescope with an Explore Scientific 20 mm 68° eyepiece and compare it in your mind to the Orion 9x50.. 

 

You can only use the former as a finder with a 2 ring mount. 

 

Jon

You pretty much nailed all the reasons I moved away from the O-ring/spring finder stalks

 

Orion put those O-ring/spring finder ring/stalks on their 50mm guide scopes as well.  What a mess that turned out to be for me.  I had 2 of those 50mm guide scopes with the helical focuser and one 8x50 stubby RACI finder.  So I had/constantly fussed with 3 scopes with the O-ring/spring setup.  The scopes are actually pretty decent, they just moved around too much in the ring/stalk.

 

In the end, all three O-ring/spring mounts were replaced by standard 3-point rings that actually bolted down and held the scopes securely.

The SV-50 is a nice finder but the AT sounds like it might be better.  Mike was getting rid of a bunch of AT finder bodies last week, I think they were around 50 bucks.  Was tempted to snag a couple.

 

But nowadays I only use an actual finder scope on my 180mm Mak, and the SV-50 works well for that so I probably won't replace it.  On all my other scopes I can just use a Telrad and a widefield eyepiece in the scope, don't need a finder scope as it's just extra weight.

Edited by Jim in PA, 06 August 2022 - 06:08 PM.

[Sarkikos]

I'd suggest the 50mm size.  It's compatible with tube diameters of 20-50mm, so 34mm is almost slap bang in the middle.

 

I'd add that the screws on mine all have a total thread length of 20 mm.

The small dual-ring mount I have now for the 6x30 RACI has an inner diameter of only 38mm.  That's only 4mm wider than the diameter of the finder.  Too tight. 

 

The smallest dual-ring in the Starpal store is 42mm.  They have a low profile and a stalk version for the 42mm.  All the others only come in the stalk version.  Though the stalk looks pretty short, maybe only about 40mm.

 

The 42mm version is 8mm wider than the 6x30 finder.

 

So I'll order the 42mm low profile version and try a 6x30 finder in it.  If it works well, I might order the 42mm with stalk also.  If it doesn't work well, I'll go on to the 50mm.

 

If the 42mm low profile doesn't work for the 6x30, I can always put a laser finder in it.

 

On the other hand, the low profile might be too low for some locations on some of my scopes?  Further needed perhaps.

 

I notice that Starpal also sells a 6x30 RACI in a dual-ring mount.  The rings are 42mm.  Hopefully, then, the 42mm are sufficient.

 

The Starpal store certainly has a wide variety of dual-ring mounts!  A lot of potential there ...

 

Mike

Edited by Sarkikos, 06 August 2022 - 07:57 PM.

[Jon Isaacs]

The SV-50 is a nice finder but the AT sounds like it might be better.  Mike was getting rid of a bunch of AT finder bodies last week, I think they were around 50 bucks.  Was tempted to snag a couple.

 

 

I have two of the AT 50 mm RACI finders. They have a couple of downsides:

 

- They're larger in diameter than finders like the SV-50, 61.7mm to 55 mm.

 

- There's too much back focus so most eyepieces have to be pulled out to reach focus. I made spacers.

 

On the plus side:

 

-The focuser is smooth and light, really good feel. The SV focuser is adequate for a finder. The AT finder is quite good at high magnifications. 

 

- The AT is about F/5, the SV is F/4. With the same eyepiece, the SV offers a significantly wider field, the AT a noticeably sharper field.

 

- Optically, the AT's are more like a small telescope. I've had three, two are exceptional, one is quite good. Exceptional means splitting Porrima (3" ) at 120-140x.

 

As a finder, it's the sharper field with the ES 20 mm 68° that has been the deciding factor, why  typically use the AT-50.

 

Jon

[rexowner]

Which 30mm system did you find on Amazon? ...

This one.  Not totally impressed with it, but still like it better than the o-ring/spring system.

https://www.amazon.c...product_details

 

These systems are usually "too long", i.e one set of the screws has to tighten down close to 

the field lens, so once it's on you can't refocus in the usual finderscope way by screwing

the thread on the objective.

[rexowner]

Here's the promised link to the StarPal finder rings:

 

https://www.aliexpre...2003262784714.2

 

If you scroll down the page it shows the maximum and minimum diameter tubes each model accepts.  There are 9 sizes ranging from 12-42mm to 130-160mm.

 

 

Here's a link to the StarPal dovetails that fit Synta shoes:

 

https://www.aliexpre...00373016715!rec

 

Rexowner et alia, the great feature of these dovetails is the huge range of distances that it's possible to set between the finder rings.  I find this extremely useful for the camera lenses I've used as finder objectives.

Great link!  Been looking for this seemingly-simple part without success for a long time.  Thanks!

[Sarkikos]

This one.  Not totally impressed with it, but still like it better than the o-ring/spring system.

https://www.amazon.c...product_details

 

These systems are usually "too long", i.e one set of the screws has to tighten down close to 

the field lens, so once it's on you can't refocus in the usual finderscope way by screwing

the thread on the objective.

Yes, this is the dual-ring system I've put my 6x30 RACI in, and that I've already complained about in post #61 above.  It is workable, but barely.  The main problem I've found is that the rings are too narrow.  There is not enough room for easy alignment of the 6x30.  Often the side of the 6x30 will butt up against the rings, or I'll run out of screw length - the same problem but from opposite sides of the rings.  The bottom line is the rings are too narrow.  4mm difference between finder diameter and ring inner diameter is not enough.  This system is really meant for a narrow laser finder, not a 6x30 optical finder.

 

Last night I ordered a different dual-ring system from Starpal on AliExpress.  It has 42mm inner diameter, the same rings Starpal supplies with their 6x30 finder.  There are two versions:  a low profile and one with a stalk.  I ordered one of each.  I'll try them both.  

 

https://www.aliexpre...000420127090!sh

 

Here is Starpal's 6x30 RACI in the rings:  

 

https://www.aliexpre...008627622718!sh

 

Mike

Edited by Sarkikos, 07 August 2022 - 06:34 AM.

[Sarkikos]

I'd also like to find rings and base to fit my 51 RedCat so I can use it as a finder.  Maybe I should start a separate thread about that.

 

Mike

[MarkMittlesteadt]

I'd also like to find rings and base to fit my 51 RedCat so I can use it as a finder.  Maybe I should start a separate thread about that.

 

Mike

I'm kind of looking for the same thing. Something I can use as a dual purpose scope. I like very simple photography (just the Moon and planets and the occasional bright DSO (M42, M31, etc.) so it would be cool to have a small scope as a finder that I could also attach a camera to, so I could photograph with it and observe visually simultaneously with the other (main) scope.

[rhaskins]

So about 3D printing:

 

Got to https://www.thingiverse.com and type in "finderscope" on the search and all types of stuff on point to this discussion comes up. Type in astronomy for a search word and all types of other astro related stuff appears.

 

Go to Google and type in "custom 3d printing near me" and you will find folks that will take your thingiverse file and print it. They will even modify it for you and then print it. I have seen a post on CN not to long ago where the buckeyestargazer,  did some custom work and printing for someone here.

 

You do not need a 3d printer to get 3d printed stuff that looks good, is functional, and you don't have to use JB Weld with 

 

For me personally I can cut, weld, fabricate and design. But if I can do it with a 3d printer I do. If you do look at buckeyestargazer's online shop most of the 3d printed parts can be sourced on thingiverse and modded to what you want exactly. And it is not rocket science nor do you have to take courses in fusion360 (my fav) to do it. Tinkercad is a powerful tool to use for modding and is fairly easy to learn.

 

Back in 2018 the best astro related item I purchased was my 3d printer. I am a mechanical engineer so I do understand that YMMV, but this stuff, finding a 3d file and getting it printed is easy.

 

Rick

[MarkMittlesteadt]

So about 3D printing:

 

Got to https://www.thingiverse.com and type in "finderscope" on the search and all types of stuff on point to this discussion comes up. Type in astronomy for a search word and all types of other astro related stuff appears.

 

Go to Google and type in "custom 3d printing near me" and you will find folks that will take your thingiverse file and print it. They will even modify it for you and then print it. I have seen a post on CN not to long ago where the buckeyestargazer,  did some custom work and printing for someone here.

 

You do not need a 3d printer to get 3d printed stuff that looks good, is functional, and you don't have to use JB Weld with 

 

For me personally I can cut, weld, fabricate and design. But if I can do it with a 3d printer I do. If you do look at buckeyestargazer's online shop most of the 3d printed parts can be sourced on thingiverse and modded to what you want exactly. And it is not rocket science nor do you have to take courses in fusion360 (my fav) to do it. Tinkercad is a powerful tool to use for modding and is fairly easy to learn.

 

Back in 2018 the best astro related item I purchased was my 3d printer. I am a mechanical engineer so I do understand that YMMV, but this stuff, finding a 3d file and getting it printed is easy.

 

Rick

When I got a private tour of the Yerkes observatory, I was introduced to the R&D engineer who worked in the basement. While he was busy spray painting a file cabinet in the hallway, he took the time to show me his shop and a cryogenic infrared camera he was designing/building for NASA. He also helped design and build the Hubble and several parts for observatories in Antarctica, among other things.

He used a 3D printer for almost every smaller part. While most of those parts were not used in the finished product, they were 3D printed prototypes for the machined aluminum ones used. Still, some of the 3D printed parts were used. 

 

Technology has come a long way, for sure. 

Edited by MarkMittlesteadt, 07 August 2022 - 10:48 AM.

[Bill Barlow]

Would you post a link to an example of the current Meade finder scope mounting base and 50mm ring?

 

Mike

I don’t have one but I would think if you google it you might find a link.  Or call Meade customer support as you might be able to order  them directly.  Or some vendors like High Point, Agena or OPT might stock them.

 

Bill

[davidgmd]

So about 3D printing:

 

Got to https://www.thingiverse.com and type in "finderscope" on the search and all types of stuff on point to this discussion comes up. Type in astronomy for a search word and all types of other astro related stuff appears.

 

Go to Google and type in "custom 3d printing near me" and you will find folks that will take your thingiverse file and print it. They will even modify it for you and then print it. I have seen a post on CN not to long ago where the buckeyestargazer,  did some custom work and printing for someone here.

 

You do not need a 3d printer to get 3d printed stuff that looks good, is functional, and you don't have to use JB Weld with 

 

For me personally I can cut, weld, fabricate and design. But if I can do it with a 3d printer I do. If you do look at buckeyestargazer's online shop most of the 3d printed parts can be sourced on thingiverse and modded to what you want exactly. And it is not rocket science nor do you have to take courses in fusion360 (my fav) to do it. Tinkercad is a powerful tool to use for modding and is fairly easy to learn.

 

Back in 2018 the best astro related item I purchased was my 3d printer. I am a mechanical engineer so I do understand that YMMV, but this stuff, finding a 3d file and getting it printed is easy.

 

Rick

  
I’d assume a 3D printed plastic part would be more prone to flexure than a solid aluminum part. Does that matter for a 50 mm finder? A 30 mm finder? Only if it’s on a long stalk?

[rhaskins]

Yes, No. Yes if it is long thin part. No if is short with thick sides and a 20% infil. Some plastics, like PETG, are fairly heavy duty.

 

I have printed airplanes that fly - 2 meter wingspan, vixen rails, vixen rail receivers, hand controller holders, spacers, lens hoods, lens caps, and a lot of other tool holders & the like without any issues. As said above, one big use for 3d printers is to make R&D parts before powering up the milling machine for the final expensive part. There is a company that is 3d printing a rocket right now albeit with a metal 3d printer instead of plastic.

 

Got to the buckeye site and looks at what he does, send him an email about failure rates. I have done a lot of parts in PLA that just do the job. From results on the "finderscope" search on thingiverse I can't help but believe that folks did not do all that design work for nothing.

 

On another note, with a 3d printer, once you start using it and see what you can do you start to see a lot of other things you can do

 

Rick

 

 

 

  
I’d assume a 3D printed plastic part would be more prone to flexure than a solid aluminum part. Does that matter for a 50 mm finder? A 30 mm finder? Only if it’s on a long stalk?

[Sarkikos]

I don’t have one but I would think if you google it you might find a link.  Or call Meade customer support as you might be able to order  them directly.  Or some vendors like High Point, Agena or OPT might stock them.

 

Bill

I did a Google search on "Meade finder scope mount base."  It returned some images, but of other bases.  Is the finder base for Meade the same as the one for Explorer Scientific?  Not much on Meade.

 

https://www.bing.com...ImageHoverTitle

 

If the Meade finder base is proprietary, not compatible with the Orion/Vixen/Synta base, then I will do a hard pass.  IMO, the standard finder base is the Orion/Vixen/Synta.  Anything else is an also ran. 

 

Seriously, whenever I acquire a telescope that has a finder base that is not compatible with the standard, I remove it and replace it with a standard finder base.  I have a plastic bin in the garage with proprietary finder bases.  The Orion/Vixen/Synta base is the de facto standard.

 

Mike

Edited by Sarkikos, 07 August 2022 - 01:21 PM.

[davidgmd]

Yes, No. Yes if it is long thin part. No if is short with thick sides and a 20% infil. Some plastics, like PETG, are fairly heavy duty.

 

I have printed airplanes that fly - 2 meter wingspan, vixen rails, vixen rail receivers, hand controller holders, spacers, lens hoods, lens caps, and a lot of other tool holders & the like without any issues. As said above, one big use for 3d printers is to make R&D parts before powering up the milling machine for the final expensive part. There is a company that is 3d printing a rocket right now albeit with a metal 3d printer instead of plastic.

 

Got to the buckeye site and looks at what he does, send him an email about failure rates. I have done a lot of parts in PLA that just do the job. From results on the "finderscope" search on thingiverse I can't help but believe that folks did not do all that design work for nothing.

 

On another note, with a 3d printer, once you start using it and see what you can do you start to see a lot of other things you can do

 

Rick

  
Thanks. I bought a printed Duncan mask from buckeyestargazer. It doesn’t have to bear any weight. I can see how that material would be pretty stable as long as it’s not a long skinny part with significant weight on the end.