Second hand mount?

[farunj]

Hi all,

I am planning on buying a second hand Orion atlas EQ-G mount. I wanted to know what to look for in the mount to ensure that it's in good condition? Cosmetically, it shows a little sign of wear, but what other pointers should I look for?

[Cornelius Varley]

Make sure that the ra and dec axis turn smoothly with clutches released and that there is little play in the them also (this can be removed by adjustment). If it is the goto mount make sure everything works, if you can ask the seller to demonstrate the mount for you.

[Astro_Baby]

Things to test...

Apply the clutches and wiggle the axis. Do they have play in them. A little play is acceptable (it can be tuned out) a lot of play may be an indication of things not being well.

Release the clutches and rotate the mount through both axis ALL THE WAY ROUND...it should ride smoothly with no weird noises or rough spots. Any sticking may indicate problems.

Apply the clutches again and with power use the handset to rotate the mount in both axis through 360' it should run all the way round in each axis with no sticking or weird noises. Note all EQ6s tend to make a weird rattly/grinding sound as they start up. Nothing to freak about its motor resonance but it should quieten down very fast. Any grinding noises once its moving may indicate problems. Note also they are usually noisier in one direction than the other.

Check the handset.

Make sure it all works, LCD display is ok and check that the handset is version 3 (earlier ones cant be software upgraded).

Make sure you have the serial cable that would have come with the mount when new which allows you to hook it up to a PC for software upgrading. Its not the end of the world if its missing but factor it in to the asking price.

Check the screw heads which may indicate whether the mount has been opened and messed with. Ask the owner as well. Dont assume because they are an expert astronomer they will be reliable at fixing mounts. Seen a few bits of kit in my time owned by experts who I wouldnt trust to sell me brick because they are careless buggers who wont have taken care of stuff

Ask about age of the mount....older ones can be problematic and may require some work. The plastic shims can break down over time. Its repairable but unless you are comfy working with mechanical stuff it could be expensive (I charge £250 for a mount rebuild and generally I wont do them these days as I am lazy and dont like being covered in grease )

Check overall condition...weights on mounts always get dinged and get rusty but the mount should be scuff free if its been cared for....the clutch lever paint ALWAYS comes off these with a bit of use so dont worry to much about that. Make sure all bolts are ok (saddle plate, alt/az and tripod) and if it still has the original altitude bolts make sure they work ok by unscrewing them all the way out. If you buy one with the original bolts that are working then change them pronto for better ones....the ones supplied are as soft as cheese and may bend and that can be nasty. If they are bent on inspection, which will be obvious as they will be reluctant to unscrew, then again you need to factor this in to your price. Personally if these bolts are wrecked you need to budget at least £100 off the price to replace....£50 for replacements plus hassle of extracing the old ones and maybe even having to have an engineering shop cut a new thread into the mount.

Guide price for a nice one is about £650.

Hope thats some help.

[farunj]

Things to test...

Apply the clutches and wiggle the axis. Do they have play in them. A little play is acceptable (it can be tuned out) a lot of play may be an indication of things not being well.

Release the clutches and rotate the mount through both axis ALL THE WAY ROUND...it should ride smoothly with no weird noises or rough spots. Any sticking may indicate problems.

Apply the clutches again and with power use the handset to rotate the mount in both axis through 360' it should run all the way round in each axis with no sticking or weird noises. Note all EQ6s tend to make a weird rattly/grinding sound as they start up. Nothing to freak about its motor resonance but it should quieten down very fast. Any grinding noises once its moving may indicate problems. Note also they are usually noisier in one direction than the other.

Check the handset.

Make sure it all works, LCD display is ok and check that the handset is version 3 (earlier ones cant be software upgraded).

Make sure you have the serial cable that would have come with the mount when new which allows you to hook it up to a PC for software upgrading. Its not the end of the world if its missing but factor it in to the asking price.

Check the screw heads which may indicate whether the mount has been opened and messed with. Ask the owner as well. Dont assume because they are an expert astronomer they will be reliable at fixing mounts. Seen a few bits of kit in my time owned by experts who I wouldnt trust to sell me brick because they are careless buggers who wont have taken care of stuff

Ask about age of the mount....older ones can be problematic and may require some work. The plastic shims can break down over time. Its repairable but unless you are comfy working with mechanical stuff it could be expensive (I charge £250 for a mount rebuild and generally I wont do them these days as I am lazy and dont like being covered in grease )

Check overall condition...weights on mounts always get dinged and get rusty but the mount should be scuff free if its been cared for....the clutch lever paint ALWAYS comes off these with a bit of use so dont worry to much about that. Make sure all bolts are ok (saddle plate, alt/az and tripod) and if it still has the original altitude bolts make sure they work ok by unscrewing them all the way out. If you buy one with the original bolts that are working then change them pronto for better ones....the ones supplied are as soft as cheese and may bend and that can be nasty. If they are bent on inspection, which will be obvious as they will be reluctant to unscrew, then again you need to factor this in to your price. Personally if these bolts are wrecked you need to budget at least £100 off the price to replace....£50 for replacements plus hassle of extracing the old ones and maybe even having to have an engineering shop cut a new thread into the mount.

Guide price for a nice one is about £650.

Hope thats some help.

Wow! Thanks a lot for the detailed guide! I will make sure most of the criteria are met with, before I buy anything! I think the mount is around 3-4 years old, but its well maintained. I will check if the motors are in good order. Thanks again!

[farunj]

This is what I am planning on getting:

http://www.cloudynights.com/classifieds/showproduct.php?product=81570&sort=&cat=21&page=2