Vibration help. Common Question

[Slowtwitch]

Hi everyone.

I'm a new amateur, and so far I've had one very good evening session viewing the moon and Jupiter.  I'm only using a Nexstar 5SE, but I was totally blown away, and now i'm hooked.

However, one of the things that was compromising my viewing quality, was the amount of vibration seen through the EP.  Some of it was induced by me everytime I focused or adjusted the scope, but most of it was through the ground, I believe.  I found it very frustrating.

I've dug a little deeper and found that it might help to put down some isolation pads on the ground under the tripod feet, fill the lower leg extensions with sand, and hang a weight under the EP tray.

I plan on doing all the above to experiment for myself, but i'd be keen to hear from anyone who may have gone a little further with these basics.  For example, if its common to hang the weight by string, has anyone experimented by actually fixing a weight to the underside of the EP tray (the 5SE has a long stud that hangs from the mount for the EP tray to attach to, I could fasten a threaded 1kg slug here), and did it make any difference?  Or perhaps the string actually serves a purpose and improve the damping by partially isolating the weight from the mount?

Perhaps some people have tried using something other than sand for the legs, like lead shot perhaps, or even a cold curing sealant or rubber, and had better results?

What about the fork arm?  Is it possible to isolate some vibration by balancing or adding some weight to the OTA, or the even to the arm itself?

Like I said, I am a total newb, so I could be totally barking up the wrong tree with these ideas (or just barking mad), but please feel free to throw any ideas or feedback at me.  I'd love to hear what others have tried and failed or succeeded at.

Thanks again.

Happy viewing.

Matt

 

[Peter Drew]

I have the 8se version which is on the same mount so inherently less stable. To be honest, I've not experimented with anything to see if the instability can be improved. The focus knob action is very light and the image shift on mine is negligible so I rely on a very careful touch to focus. I regularly use 400x without too much difficulty. 

[Slowtwitch]

34 minutes ago, Peter Drew said:

I have the 8se version which is on the same mount so inherently less stable. To be honest, I've not experimented with anything to see if the instability can be improved. The focus knob action is very light and the image shift on mine is negligible so I rely on a very careful touch to focus. I regularly use 400x without too much difficulty. 

I thought I read something saying the 4SE/5SE are on one model mount/tripod, and the 6SE/8SE are on another, probably better mount/tripod?

[Cosmic Geoff]

It  helps if you keep the tripod legs at minimum length and observe sitting on a stool. And if you set up on concrete and not on yielding ground.  The theory of the 'added weight' is that it is hung loosely from the tripod and acts as a damper. (The same idea is used in tall buildings in earthquake zones IIRC). I tried it on ny Nexstar with the lead-acid battery and it helps a bit (I think).

[Peter Drew]

2 hours ago, Slowtwitch said:

I thought I read something saying the 4SE/5SE are on one model mount/tripod, and the 6SE/8SE are on another, probably better mount/tripod?

I think I misread your OP, the 6se certainly is on the same mount. 

[Anne S]

I always used the vibration suppression feet. They help quite a bit. Particularly on concrete. On grass I used to make sure the tripod feet were pushed into the ground well, otherwise they sink when you put the telescope on.

[Dave In Vermont]

One very good - and mostly unknown - trick, after anti-vibration-pads under each leg of the tripod, is to hang a weight (around 10lbs or so) from the center (or as close as you can) of the mount so it's hanging in mid-air above the ground. This serves to set-up it's own frequency of vibrations and this counters the vibrations from the usual one's that are causing you trouble.

It is difficult to explain the odd-ball physics involved - but it can work like magic! I was having the same problems you are describing. So I hung a 10lb. weight on a cord about 15" long under my AZ-4 which was holding my 150mm F/12 Maksutov - from the center-bolt on the mount - and around the center-tray - and Voila! No more vibrations - even if a danced in combat-boots!

It matters not what you use for a weight. I happened to have some from an old set of barbells, but I'd have used a toaster if I had one on hand! And it also doesn't matter if it will go over the specified weight the mount is rated for holding. It all is compensated for. So give it a shot!

Best wishes -

Dave

[Slowtwitch]

3 hours ago, Dave In Vermont said:

One very good - and mostly unknown - trick, after anti-vibration-pads under each leg of the tripod, is to hang a weight (around 10lbs or so) from the center (or as close as you can) of the mount so it's hanging in mid-air above the ground. This serves to set-up it's own frequency of vibrations and this counters the vibrations from the usual one's that are causing you trouble.

It is difficult to explain the odd-ball physics involved - but it can work like magic! I was having the same problems you are describing. So I hung a 10lb. weight on a cord about 15" long under my AZ-4 which was holding my 150mm F/12 Maksutov - from the center-bolt on the mount - and around the center-tray - and Voila! No more vibrations - even if a danced in combat-boots!

It matters not what you use for a weight. I happened to have some from an old set of barbells, but I'd have used a toaster if I had one on hand! And it also doesn't matter if it will go over the specified weight the mount is rated for holding. It all is compensated for. So give it a shot!

Best wishes -

Dave

Thanks Dave. I thought the length of the string that the weight was hung from would have an impact on its ability to dampen the vibrations. I'll take a look for some antivibration pads too.

Many thanks, and clear skies. 

[Dave In Vermont]

You can also make your own pads from some Sorbothane®-pads, available through Amazon for one place, and save a pile of £££. Ready-made anti-vibration-pads can run upwards of $60/3 over here. $20 will buy a bag-full.

I made my own <below> which I bagged as they're sort of 'sticky' and pick-up debris. I found these almost 2X quicker at damping-out vibrations compared to the brand-named ones.

Dave

 

 

[ronin]

I guess there is not a lot that can realistically be done, the anti vibration pads may help by isolating the tripod and are easy enough to get hold of and try. Never been keen on the idea of filling the legs with sand. based on having stripped and cleaned an HEQ5 tripod the last thing I can think of is filling the legs with anything.

Hanging a weight from the center I have read of and should to an extent work, The idea seems to be that the vibration is preferentially transferred to the free hanging weight and that this gently oscillates rather then the more rigid tripod. It does however mean attaching and also carrying round a few kilo's of additional weight.  Technically I think it relies on the frequency of oscillatiojn of the hanging weight being at the same as the problem vibrationns.

The expensive solution (well not solution but improvement) is likely to be get the mount for an 8SE. The 4 and 5 are on one mount and the 6 and 8 on a bigger one. THe respective mount is adaquate for the smaller OTA but is at or beyond it's limit on the bigger.

Another aspect is the focal length, being a long focal length then any vibration is seen more at the eyepiece. So the scope design will contribute, and you cannot change that.

 

[Slowtwitch]

Some great tips, and advice from you guys.  Thanks again.

[Yearofthegoat]

9 hours ago, Dave In Vermont said:

I hung a 10lb. weight on a cord

Hi Dave Was that a stretchy cord, or a wire-based one (i.e. stiff)?

I have bungees, string, paracord, old washing line, shoelaces and old wire so I can choose!

Thanks.

 

Oh and next doors pooping cat is about 10lbs I reckon.

[Dave In Vermont]

10 hours ago, Yearofthegoat said:

Hi Dave Was that a stretchy cord, or a wire-based one (i.e. stiff)?

I have bungees, string, paracord, old washing line, shoelaces and old wire so I can choose!

Thanks.

 

Oh and next doors pooping cat is about 10lbs I reckon.

Just some regular twine. No elasticity or wires. Fabric-type twine you'd truss-up a chicken or turkey with during cooking to keep the stuffing in.

Works so well that I was astounded!

Dave

 

p.s. - don't you DARE lynch the Cat! Or I'll send my "Cat" over to "talk" to you.....

 

 

 

[Yearofthegoat]

Thanks.

That's one cross cat. Don't send him across the pond, he looks waaaay over 10lbs

Of course I would never do any such thing to a living cat...

[skfboiler]

My Orion Astroview 6 EQ is an EQ-3 mount and it shakes a bit while focusing.  I solve the shakes by installing a motorized focuser.  Contact Celestron and see if they have one compatible to your focuser.

[Dave In Vermont]

Hi there SKF -

For a good type of motorized-focuser from the USA, I've used the JMI MotoFocuser's on quite a few scopes - including my 127mm F9.3 Refractor for over 20 years without a problem:

http://www.jimsmobile.com/buy_motofocus.htm

Jim's a very nice guy, as well. He's always willing to help with any questions. I'm unsure about their availability in the UK or Europa, but an email would solve that.

Enjoy!

Dave

[noah4x4]

OK....a bit radical..... but this has some possibilities.... 

I use my conservatory for storage and I run back and forth to fetch eyepieces etc. My wife got so fed of me trailing in grass clippings and muddy footprints on damp days that I invested in some good quality artificial grass. I didn't like mowing too much either, and it looks fabulous. So we are both happy. Then came a problem.

I could not easily mark the regular position of my tripod legs which is helpful during a Polar Align.  I also didn't want the hard points of my tripod to penetrate or damage the artificial grass. So I made the wooden triangle depicted in the image with a soft furniture castor cup at each corner into which I insert my tripod legs. This wooden jig also has a Silva compass affixed. This unique device hence helps easily identify the N/S Meriden and with my wedge latitude set correctly it typically gets me within 2° of a perfect polar align before I even commence an EQNorth Align and ASPA. It is also great for telescopes like a Nexstar 4SE that have a built in wedge but no (wedge) Azimuth adjustment as you  can simply nudge this (e.g. to rotate the tripod) with your toe rather than lift your heavy equipment.....but I digress. 

What I have found as an additional benefit is the consistent springiness of the artificial grass under this supporting device seems to negate eyepiece vibration far better than my proper (expensive) vibration suppression pads. I think it's the way that the triangular device evenly "floats" on the grass rather than the mere cushion impact of the grass alone. I also think it reduces vibration from my footsteps. As a square metre of good quality artificial grass costs under £20 and is easily transportable, it might be worth others trying this under their vibration pads or any other 'circular 'cups (not necessarily on a wooden triangle) to see if it assists them. As the small square of grass can be rolled away it might also protect your natural grass that inevitably gets trampled during a night's observing, albeit I have had had it laid permanently.

I wonder, can I claim the patent on the world's first all weather 3G grass observing platform as well as my triangular polar alignment jig?

 

[triton1]

What people will do to get out of cutting the grass!.Nice idea though.?

[noah4x4]

2 hours ago, triton1 said:

What people will do to get out of cutting the grass!.Nice idea though.?

Hmmmnn Triton1. ....

At least I have not flocked the inside of my OTA with artificial grass ROFL ?

 

[Macrob1]

21 hours ago, noah4x4 said:

I wonder, can I claim the patent on the world's first all weather 3G grass observing platform as well as my triangular polar alignment jig?

 

 

[Macrob1]

Nope you can't. I also use a square of the artificial grass - it used to be my golf chipping mat. And a bonus is it's nice to kneel on. I really like the triangular jig though and I will allow a patent claim for it.

[noah4x4]

4 hours ago, Macrob1 said:

Nope you can't. I also use a square of the artificial grass - it used to be my golf chipping mat. And a bonus is it's nice to kneel on. I really like the triangular jig though and I will allow a patent claim for it.

Claim filed in US and Europe. You can have the patent in Oz. 

More seriously, it's a simple way to dampen vibration compared to normal grass,  but it ideally needs the "jig" or at least some "cups" to help spread the 'load' from the spikes at the bottom of each tripod leg so that they 'float' on the springy artificial grass (e.g. rather than penetrate down to the backing).

The triangle jig has proved to be an amazing innovation. I devised it because I initially struggled to get my heavy Evolution on wedge sufficiently accurately along the N/S Meridian for a "rough align" because I can't see Polaris. That meant my two star (EQNorth) cal-stars were often way beyond my FOV after the firsr ASPA because the initial PAE was too large.  To resolve this, I had previously marked my tripod leg locations at home after a previous successful polar align by hammering three six inch nails in the real grass,  but that didn't work when away at dark sky locations and I didn't want to penetrate my expensive substitute grass. Now by first aligning the jig using its compass; then setting up my tripod in its castor cups; this solved the N/S Meridien  challenge in a few seconds; with the bonus of further negating vibration as it 'floats' on the artificial grass. 

[barkis]

On 2017-5-10 at 07:36, Dave In Vermont said:

You can also make your own pads from some Sorbothane®-pads, available through Amazon for one place, and save a pile of £££. Ready-made anti-vibration-pads can run upwards of $60/3 over here. $20 will buy a bag-full.

I made my own <below> which I bagged as they're sort of 'sticky' and pick-up debris. I found these almost 2X quicker at damping-out vibrations compared to the brand-named ones.

Dave

 

 

Are you sure they aren't Pontefract Cakes Dave? 
 I jest of course,  but a pic. here to show the similarity 

[barkis]

Matt, many years ago I was plagued with the same problem.
Whilst viewing an object, even at medium powers, I was looking at blurred images.
I noticed when I lightly touched the focuser, the blurring cleared.
I trace the  problem to my RA drive, which was powered by a synchronous Motor, 
showing my age now . I verified it by switching the drive off, and sure enough,
everything cleared.
I'm not suggesting your problem is the same,, but just stop the drive to make sure.
Today's drives are more sophisticated, and unlikely to produce the effect I had, but worth a punt 
just as a quick elimination.

[iapa]

On 09/05/2017 at 13:34, Slowtwitch said:

Hi everyone.

I'm a new amateur, and so far I've had one very good evening session viewing the moon and Jupiter.  I'm only using a Nexstar 5SE, but I was totally blown away, and now i'm hooked.

However, one of the things that was compromising my viewing quality, was the amount of vibration seen through the EP.  Some of it was induced by me everytime I focused or adjusted the scope, but most of it was through the ground, I believe.  I found it very frustrating.

I've dug a little deeper and found that it might help to put down some isolation pads on the ground under the tripod feet, fill the lower leg extensions with sand, and hang a weight under the EP tray.

I plan on doing all the above to experiment for myself, but i'd be keen to hear from anyone who may have gone a little further with these basics.  For example, if its common to hang the weight by string, has anyone experimented by actually fixing a weight to the underside of the EP tray (the 5SE has a long stud that hangs from the mount for the EP tray to attach to, I could fasten a threaded 1kg slug here), and did it make any difference?  Or perhaps the string actually serves a purpose and improve the damping by partially isolating the weight from the mount?

Perhaps some people have tried using something other than sand for the legs, like lead shot perhaps, or even a cold curing sealant or rubber, and had better results?

What about the fork arm?  Is it possible to isolate some vibration by balancing or adding some weight to the OTA, or the even to the arm itself?

Like I said, I am a total newb, so I could be totally barking up the wrong tree with these ideas (or just barking mad), but please feel free to throw any ideas or feedback at me.  I'd love to hear what others have tried and failed or succeeded at.

Thanks again.

Happy viewing.

Matt

 

I had a similar issue with the 130SLT mount a few years ago.

Partially resolved - about 90% so - by suspending a 6 pack of 1.5L bottles of water from the eye piece tray. Made a great difference.

Acts as a pendulum and counters vibrations.

 

Also bought a set iv vibration pads for a washing machine for about £6.