Dodged a bullet

[Nakedgun]

~

The toys we acquire in pursuit of this hobby come dear to us in many cases, and it's tough to admit you've made a boneheaded move which nearly resulted in the destruction of a fine optical instrument.

My TEC MC150 mak-cass has rings bolted to a Losmandy D-type dovetail plate onto which I have added an ADM Vixen-type adapter. Tuesday evening I mounted the scope on a non-goto CG-5, tightening down the mount's locking bolt securely, then loosening it enough to slide the whole thing forward just a bit to offset the weight as I would be using a binoviewer, then re-tightening the locking bolt again.

Next I rotated the R.A. axis to horizontal to balance the counterweights, and watched in horror as the scope pried itself out of the CG-5's saddleplate, dropped three feet and thudded onto the concrete slab!

You can imagine my thoughts and emotions at that instant....

I heard no glass break and as I reached down to pick it up my mind raced - HOW?! How could such a thing have happened?!

Not only had no glass broken, the finderscope mounted atop the OTA was not damaged, the diagonal with eyepiece was still intact, the ring-handle attached to the rear of the OTA was undamaged, as well!

So, what's going on here? The scope fell in such a way that the impact was absorbed by the detachable steel dewshield and then the aluminum rings, which are felt-lined. The OTA never touched the deck.

But why did it separate from the mount? I pushed the Vixen dovetail plate forward just enough that the rear portion of the mount's saddleplate was no longer wedging the dovetail.

I mounted the scope again and checked operation, finding the collimation off just a teensy bit, but now the secondary holder could be turned in the meniscus by hand.

I phoned TEC today and was relieved to hear that Yuri would walk me through the process of re-tightening the secondary by hand; it would not have to be shipped back to them.

 

Dewshield a tad worse for wear:

 

 

 

DON"T slide the Vixen dovetail, slide the Losmandy dovetail, stupid!

 

 

 

To say a valuable lesson was learned would be understating the case considerably.

 

 

.

.

[josefk]

Ouch!  Sounds like you’ve been lucky though ultimately. 

[F15Rules]

🤦🤦🤦😱

😌..a close escape..but thankfully an escape nonetheless 👍😊.

We've all done daft things like that though, so we live and learn from it. Don't let it spoil your Christmas!

Dave

[Alan White]

Oh how I feel and share your pain and terror, sounds all to familiar to my experience this year.
You have been very lucky in the outcome of this misfortune.

I still stand with the vixen or other rail principal being awful, the scopes should not be made to slide on a frail, its a rceipe for disaster.|
Vixen when they came up with the rail idea, had it fixed in one place, that idea was then diluted by other over the years.

New clamping design needed? Nope.
What we need is going back to the old ways I think.

Good luck with the scope repairs, it can be done with patience and help, thats how I now have Lazarus my ED103 again.

[michael.h.f.wilkinson]

Glad things weren't worse. That's an absolute nightmare. I gather from your description that the CG-5 has the same (poor) saddle plate as my EQ3-2, and very different from the (much better design) Vixen Great Polaris I have. In the latter the dovetail bar is clamped against a solid flat surface , in the EQ3-2 it is clamped against two narrow bits of metal. The Vixen GP design means even short dovetail bars are always securely held, in the latter, you can get your kind of accident.

[Franklin]

19 minutes ago, Alan White said:

Lazarus my ED103 again.

Very apt! Glad you got it back.

[Franklin]

There is a lot to like about the old Vixen bar with the safety notch. Ok, you can't slide the dovetail up and down for balancing but you just move the tube through the rings for that.

[Telescope40]

Sorry to hear this.  I've got a bit paranoid when bolting up my scope to the mount of late.  I end up using a rather bright torch, held in my mouth, to check that the bar is totally seated correctly in the clamp mechanism. Sod any dark adaptation for a while. The security of my scope comes first.  I even tilt the whole mount slightly using the scope to make sure nothing is moving incorrectly / loose. 

Bit extreme I guess but not as extreme as my reaction if the ground and an OTA got into a very violent meet up. 

Glad to hear no lasting damage occurred.    

John 

[JeremyS]

There’s been a spate of falling ota’s on here and CN lately 😳

I too am paranoid each time I mount one on my ota’s

[Peter Drew]

Although you can't eliminate human error, dovetail clamps rather than the dovetails themselves, are often inadequate.  Specially the dual fit versions that result in too shallow a holding face and don't get me started on the spring loaded ones.  Finally, if you're going to drop an OTA, make sure it's a Mak-Cass.     😱 

[dweller25]

You were very lucky @Nakedgun 👍👍👍 Nice scope 🙂

I use a standard Vixen GP with two locking bolts and always triple check that the scope dovetail is located correctly and both bolts are tight.

So far so good……

PS - Now you should go do the lottery 🤣

Edited December 22, 2022 by dweller25

[Nakedgun]

6 hours ago, Peter Drew said:

Although you can't eliminate human error, dovetail clamps rather than the dovetails themselves, are often inadequate.  Specially the dual fit versions that result in too shallow a holding face and don't get me started on the spring loaded ones.  Finally, if you're going to drop an OTA, make sure it's a Mak-Cass.     😱 

~

I swear, TEC built them like tanks!

 

 

.

[Nakedgun]

5 hours ago, dweller25 said:

You were very lucky @Nakedgun 👍👍👍 Nice scope 🙂

I use a standard Vixen GP with two locking bolts and always triple check that the scope dovetail is located correctly and both bolts are tight.

So far so good……

PS - Now you should go do the lottery 🤣

~

I believe I will.

 

 

.

[F15Rules]

7 hours ago, JeremyS said:

There’s been a spate of falling ota’s on here and CN lately 😳

I too am paranoid each time I mount one on my ota’s

Are you trying to drum up New Year business for your Handle making company, Jeremy?🙃

Dave