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AZ-EQ Losmandy? GM8G GM811G G11G but not G11T

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#1 JAC51

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Posted 23 May 2020 - 02:27 PM

I can be a bit slow on the uptake I have only just realised, apart from the obvious tucked in motors, what else has changed with the new Losmandy mounts compared to my 10 year old GM8. They have moved the worm block from below the RA axis. The worm block is now above the RA axis. The latitude scale now starts at 0 degrees and goes to 70 degrees while on my old GM8 it starts at 10 degrees and goes up to 70 degrees, this is actually what I first noticed. This is the same for the new GM8G, GM811G,  G11G,  but not the G11T. The G11T still has the worm block below the RA axis and the latitude scale for this mount still starts at 10 degrees.

 

Does this mean that if you set your RA to 0 degrees mechanically you have a goto azimuth mount in the same manner as the Skywatcher AZ-EQ6 . The problem would be a software one with Gemini needed updated code to handle this. The RA axis handling altitude while the declination axis is the azimuth.

 

On a related matter what is terrestrial tracking?

 

I assume it’s not what I’m describing above or they could simply already have called the mount for example the AZ-GM8G

 

John



#2 Wildetelescope

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Posted 23 May 2020 - 05:47 PM

I can be a bit slow on the uptake I have only just realised, apart from the obvious tucked in motors, what else has changed with the new Losmandy mounts compared to my 10 year old GM8. They have moved the worm block from below the RA axis. The worm block is now above the RA axis. The latitude scale now starts at 0 degrees and goes to 70 degrees while on my old GM8 it starts at 10 degrees and goes up to 70 degrees, this is actually what I first noticed. This is the same for the new GM8G, GM811G,  G11G,  but not the G11T. The G11T still has the worm block below the RA axis and the latitude scale for this mount still starts at 10 degrees.

 

Does this mean that if you set your RA to 0 degrees mechanically you have a goto azimuth mount in the same manner as the Skywatcher AZ-EQ6 . The problem would be a software one with Gemini needed updated code to handle this. The RA axis handling altitude while the declination axis is the azimuth.

 

On a related matter what is terrestrial tracking?

 

I assume it’s not what I’m describing above or they could simply already have called the mount for example the AZ-GM8G

 

John

Losmandy does not make a goto Alt-az mount.  All the mounts you list are GEMs.  Changes to the Losmandy mounts overtime have been incremental.  This is purposeful, as Scott has always strived to maintain backward compatibility.   My 1990's vintage GM8 with digital drive could be completely upgraded to a GM8, with tucked in motors, Spring loaded worms and Gemini II if I wanted.  The most recent change has been the spring loaded worms.   Another innovation has been the modular nature of the Dec and RA shafts which enables mixing and matching the Dec of the GM8 with the RA of the G11.  The G11 T is a marriage of the G11 dec with the Titan RA.  Sadly a full up Titan seems to no longer be available.  The AZ8 is a manual alt az mount that is based on the GM8 gearing, but it is not Goto  or motorized.   

 

Hope this helps!

 

JMD



#3 JAC51

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Posted 24 May 2020 - 02:40 AM

Hello thanks for the reply JMD as it looks like the RA axis on the new mounts will go parallel to the ground (0 degree latitude) I assumed that this was purely a software problem (subject to the telescope tube clearing the support below). I was thinking that as you said about incremental changes being made, until Losmandy was very sure that the Gemini software could handle operating azimuth and altitude as well as RA and DEC they would not introduce this feature.

 

I have though just thought of another problem,  the cables to the motors wrapping around the mount, especially if you turned through more than 360 degrees.

 

The skywatcher AZ-EQ's use thought the mount cabling?

 

My interest in this all came out of thinking of using binoviewers without them tilting as the mount rotates and so avoiding having to correct this all the time. For visual use in general, which I almost always do, a more consistent seat height would also for me be a plus.

 

I'm still unsure what terrestrial tracking is on the new spec sheet.

 

Is this RA axis latitude set  0 degrees and then use the dec motor to pan around the horizon?  Perhaps for using a telescope as a terrestrial spotting scope out of a window?

 

John



#4 ebacon

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Posted 24 May 2020 - 07:42 AM

On my CGEM Terrestrial = Tracking Off.  It used for stationary objects, e.g. spotting scope.



#5 JAC51

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Posted 24 May 2020 - 08:02 AM

O of course on a Losmandy with slip clutches and tracking off you can even simply push the mount around.



#6 Wildetelescope

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Posted 24 May 2020 - 09:11 AM

On my CGEM Terrestrial = Tracking Off. It used for stationary objects, e.g. spotting scope.


Same for losmandy.

Jmd


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