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EQ in Alt-Az mode?

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#1 surfindogg

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Posted 24 March 2009 - 04:57 AM

I have a Megrez 90 currently mounted on a photo tripod - not the best solution. What I would like to know is if an EQ mount can be used as an alt-az mount and if so what would be best for mounting this scope and how. Looking to spend not much more than $200 so probably second hand and I am in the UK. Oh! And not too heavy!

My thought is that I could use it for grab and go, and when I have more time set it up properly as an EQ. I am thinking head only as I am hoping to pick up a wooden tripod to put it on.

Thanks in advance for wise words and advice.

#2 Luigi

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Posted 24 March 2009 - 06:58 AM

Any EQ that can be set for zero latitude can be used in alt-alt mode. (yes, alt-alt, not alt az). You need a mount that can be set for 90 degrees latitude to work in alt-az mode.

#3 1_old_dog

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Posted 24 March 2009 - 07:12 AM

Howdy

Some EQ mounts will work in alt-az mode some will not without a bit of modding.

I had an older EQ1 that went into in alt-az mode for my ST80 (no modding) . I also had an EQ3 that with a bit of grinding worked really well in alt-az, but it was too heavy so I went back to the EQ1 for the ST80.

I have some pics somewhere of the mod I did on the EQ3, I'll see if I can find them.

hope this helps
OD

#4 1_old_dog

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Posted 24 March 2009 - 07:17 AM

Luigi
really?? alt-alt?? never heard of that mode. I'm not sure I'm following you? can you explain?

#5 1_old_dog

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Posted 24 March 2009 - 07:29 AM

here's a pic of the EQ1 in alt-az (alt-alt?) mode.

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#6 1_old_dog

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Posted 24 March 2009 - 08:08 AM

This is the EQ3. The mount sat at 85° so I had to grind a bit of material away so it would hit 90°

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#7 surfindogg

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Posted 24 March 2009 - 09:04 AM

And slow-mo controls too - I think this is worth having a go at. All I need now is to find a suitable mount and tripod.

Thanks all. Any more suggestions welcome.

#8 tahmi3

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Posted 24 March 2009 - 11:52 AM

take a look at the vixen polaris mount. Celestron used to sell them with their 4.5" reflector. It will go into alt-az with no mods. It had the short non-extending wooden legs. A very nice mount with slo-mo hand controls. I'm not sure about the super polaris.

#9 Luigi

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Posted 24 March 2009 - 12:16 PM

>>>alt-alt?? never heard of that mode<<<

Alt alt has the first axis horizontal rather than vertical as in an alt-az or pointing at the pole as in a EQ. It's equivalent to a gimbal mount. There is no "Dob hole" at zenith. The equivalent of Dob holes occur on the horizon off the ends of the first axis. These types have traditionally been used in satellite tracking.

#10 hudson_yak

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Posted 24 March 2009 - 12:22 PM

Yes, this is worth a try, though problems occur with counterweights banging into the tripod at low altitudes, and meridian flip (not exactly "meridian", but similar idea) is still required. Though I guess it could be easier to just pick the whole contraption off the ground and rotate it instead.

On the plus side, the scope at least looks a little more right-side-up on the mount most of the time. On the negative side, you still need the counterweight on the Dec shaft, and there's no good way to get the weight of that and the scope balanced near the center of the tripod.

Mike

#11 1_old_dog

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Posted 24 March 2009 - 04:26 PM

Thanks for the explanation Luigi.

OD

#12 astroN00B

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Posted 24 March 2009 - 05:46 PM

I have a Vixen Polaris with long wood refractor legs that I use in alt-az. If I had to do it again, I'd go for a mount that wasn't as heavy and bulky. The slow motion controls are nice though.

Just my thoughts...

#13 mischief

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Posted 24 March 2009 - 05:55 PM

Surfindogg, If you could spend a little more than $200 why don't you think about getting an alt/az mount. The Astro-Tech Voyager has had very good reviews; you can check some of the threads on this forum. It costs $299, has slow motion controls and can be modified with Microslew motors from JMI. Then later you could get an EQ mount. The Voyager isn't too heavy; the tripod is fairly sturdy. Then you wouldn't have to bother with mods of an EQ mount. Just an idea; hope it helps.

Dorothy :getem:

#14 surfindogg

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Posted 25 March 2009 - 05:58 AM

The voyager is not so common this side of the pond but I did have a look at it. Seems very well made. I have looked at a number of alt-az mounts but was thinking that an EQ-Alt-Az mount would give me the best of both.

I shall keep my eyes peeled for a second hand EQ to experiment with I think.

Thanks again to all for all advice and info.

#15 deezdrama

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Posted 10 April 2009 - 11:32 AM

can the orion atlas/eq-6 mounts reach 90* to be used in alt-az mode?






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