Tracking near the zenith with an EQ mount

[AstroTom (Tom)]

Hi All,

My setup is a Skywatcher Black Diamond ED120 on an AZEQ6 mount. In the coming months I'm planning to photo the lagoon and triffid nebulas each of which pass directly overhead. Last weekend I was tracking the southern pinwheel galaxy and was noticing once it was quite high in the sky, my canon camera was very close to one of the tripod legs.

The galaxy was high in the eastern sky and my counterweights were on the eastern side of my mount. The telescope was pointing almost upwards. I have been trying to think how the mount tracks in dec and right asension through a night. If it was only tracking in right ascension then it would seem that my counterweights would get higher and the scope would rotate around and hit into the tripod legs.

I was wondering whether anyone knows whether there is a risk of hitting the tripod legs or whether the dec axis also rotates and the scope misses the legs. If I track something in the western sky then my counterweights are on the western side and my scope points up into the western side. I'm just not to sure about what happens Inbetween when the scope is pointing directly up.

Anyway apologies if some of the above is hard to make sense of, it's a little difficult trying to explain it in words and without the scope. Any advice would be much appreciated. Obviously I don't want to point it up and potentially damage my scope.

Regards,

Tom

[glend (Glen)]

Simple solution (that I use) is to get the Skywatcher EQ6 Pier Extension, which raises the height of the mount head so that most long refractors will clear the legs. I paid about $90 for mine from Andrews ( it was Skywatcher white).

Bintel has them in black:

http://www.bintel.com.au/Mounts---Tr...oductview.aspx

[RobF (Rob)]

Hi Tom

You could also set up a software limit in EQMOD (if you're using it). I don't know the latest synscan version well enough, but may well be an option to stop tracking if past certain number of degrees past meridian.

[AstroTom (Tom)]

Hi Rob, Glen,

Thanks for the advice.

I ordered the eq6 pier extension and it arrived today. Glen do you keep the extension fixed to the mount head when your not using it? I notice that to screw the pier extension into the mount head you have to take the base of the pier extension off. I'm tempted to just leave it on the mount head to save having to connect this together all the time.

Anyway thanks for the advice,

Tom