Setting up the CGEM 12" telescope without backstrain.

On Sunday 5^th December strong winds developed in the later evening with powerful gusts that threatened to blow the entire telescope over. I nervously watched the telescope being hit by these gusts for several hours.  This resulted in me removing the OTA from the mount at 3.30 a.m. local time early on Monday morning as I really needed some sleep!  I removed the OTA together with the camera/focus assembly in its entirety and brought it indoors. The strong winds continued through Monday and again no imaging was possible the next night. 

 It was partially cloudy on the Monday night but there was a fantastic evening view with Orion rising on its side with really bright stars in the dark sky. The only light was from the 2 adjacent walkway lights and some light from the local town of Turre (out of view on the other side of the hill) reflecting off the passing clouds. I awoke this morning (Tuesday) to find a blue sky and sunshine on the Almeria plain 1000 ft below Cabrera but still breezy so I will not reassemble the telescope until I am sure the strong winds are not returning.

The wind continued to prevent any activity until Thursday 9th December when I was able to reassemble the telescope. The day was warm with my car thermometer registering 33 degrees when parked and going down to 25 when I was driving - a more realistic estimate of the temperature.

The wind had gone completely and it was effectively a warm summers day!

As I am on my own and the OTA with equipment weighs over 50 lbs I have to be very careful not to injure myself lifting the OTA back onto the mount so I use a technique that I discovered via “You Tube”  from a crazy American amateur called Greg who considers a C14 to be a small portable scope. It comes in two videos – in the first he did not know of this technique  – and used brute force to mount the C14 OTA referring to “girly men” who whinged about heavy OTAs – then in the second – somewhat abashed he had been told by others of the technique I  now use – he revises his thinking!! Although I have an LX200 12" rather than a C14 in Spain I believe that the weight of the 12" is similar to the C14 - I believe Meade mirrors per square inch are heavier than the celestron mirrors - or perhaps the mirror supports are heavier. Anyway - I adopt the technique he eventually demonstrated.

Links coming later but first the technique.

The essential thing to have is an observing chair – I had brought a kitchen stool in my truck for that purpose. The process is shown in the images below. The mount is set up as shown below with the weights removed – adjacent to the chair.

The next stage is to put the OTA onto the chair as close as possible to the saddle on the mount – using books or telephone directories to get the correct height.

Then lift the OTA onto the chair with the dovetail adjacent to the saddle.

I then adjust the saddle screws so that the “jaws” of the saddle are wide enough to accept the dovetail maximum width – without unscrewing the saddle adjustment completely – and push the mount into the saddle – tightening up the saddle screws to clamp the  dovetail.

The position of the OTA in the saddle is adjusted later during balancing. Care is needed as the clamps on the CGEM axes are difficult to lock just by hand – I must admit I (carefully) use my truck jack handle to tighten them as it conveniently fits over the clamp levers. I believe you can buy extenders as an extra – obviously an initial design issue.

 

The link to You Tube Video 1 is here

The link to You Tube Video 2 is here