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Atlas GEM Used As Crude Alt-Az Mount?

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#1 10gauge

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Posted 08 September 2012 - 07:52 PM

Before committing serious $$$ on a DM-6 or a T-Rex for my anticipated TEC140, I thought I'd pose a silly question: How can one use an Atlas or any GEM for that at matter, in any sort of practical alt-az capacity?

In other words, is there a way to disengage the gears of the GEM to allow free movement to sweep faster in both axes then engage the gears to track?

If so, is there any resistance to any weight imbalance to prevent the scope from falling to one side?

Thanks guys!

#2 buaku

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Posted 08 September 2012 - 10:15 PM

I tried that not too long ago. Basically set the altitude to 0 degrees and it functions like an alt-az. I have an 8" newt on there and it totally hits the legs if you point it too high.

The hard part was dealing with the alt adjustment screws and getting it put down to 0. I totally took one of the screws out. After that it was just stiff to move it all the way, but I finally got it there!

You can disengage the clutches and have free movement of the mount. As long as it's balanced OK it shouldn't go wildly swinging anywhere.

I'm have no clue how tracking would work. I've only used it manually so far. Haven't had time to figure out how tracking works.

I know I've seen people here talk about the Meade LX80. I guess it can function as a GEM or Alt-Az.

I ended up buying a Unistar for my Alt-Az needs. Haven't had time to get it outside, but it seems to move and balance well in the house! Plus its waaaay lighter.

The Atlas is just a beast to move outside. I knew it was heavy, but I didn't realize how heavy until after I got one!

#3 brianb11213

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Posted 09 September 2012 - 02:06 AM

Basically set the altitude to 0 degrees and it functions like an alt-az.

In a very strange way ... setting the latitude to 90 degrees (polar axis pointing straight up) is the way to go. The latitude adjusters don't let you get there but a "bent" pier extension allows this setup.

With the latitude set to zero, your natural movement in azimuth is against the azimuth adjustment mechanism, which will not stand the strain for long. With the latitude set to 90 degrees, the RA axis carries azimuth and the Dec axis altitude.

#4 rmollise

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Posted 09 September 2012 - 07:11 AM

Before committing serious $$$ on a DM-6 or a T-Rex for my anticipated TEC140, I thought I'd pose a silly question: How can one use an Atlas or any GEM for that at matter, in any sort of practical alt-az capacity?

In other words, is there a way to disengage the gears of the GEM to allow free movement to sweep faster in both axes then engage the gears to track?

If so, is there any resistance to any weight imbalance to prevent the scope from falling to one side?

Thanks guys!


Oh, you can disengage the gears--by undoing the locks--and you can set latitude to zero, but the mount WILL NOT track in alt-az. It will only track in this setup if you move to the north or south poles. The answer? Wait for the Synta/Skywatcher AZ EQ-6 or look at one of the Ioptron mounts.

#5 10gauge

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Posted 09 September 2012 - 08:10 PM

Thank you buaku, Brian, and Rod! I have looked into the Unistar Deluxe, but from an intuitive look, I am not sure if it can handle 250x smoothly. Let us know how it works out in first light.

The Atlas has a long track record, but I couldn't find much information on the quality of the Meade LX80. I saw one video on YouTube where the whole mount wobbled?! Maybe it was a fluke....
Are there any reports on how good the Ioptron or SW AZ EQ-6 are?

Yes the Atlas is heavy, that's why I'd like to consolidate my equipment to the least, both in terms of weight and space since I'll be driving 80 miles for DSO visible only operation. How heavy are the LX80 and AZ EQ-6?

Thanks guys!

#6 buaku

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Posted 09 September 2012 - 09:46 PM

I'm really hoping I'll get a chance to get out this coming weekend. I don't have any really high-magnification eye-pieces but I could try and barlow the ones that I have.

I also pondered the Duo-T. I keep reading good things about it and it has slo-mo controls. But I've also read the slo-mo controls can be hard to get to at times. Did you totally rule that one out? I remember another thread of yours asking about it.

#7 10gauge

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Posted 09 September 2012 - 10:45 PM

Yea, I asked about the Duo T as a simple Alt-az for the TEC140, but no one responded. I am not sure if the Duo T can carry the weight?

#8 Mkofski

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Posted 09 September 2012 - 11:55 PM

Hi... I had a SkyTee 2, the European version of the Duo T. I don't remember the stated capacity of the mount but it handled a C8 SCT and a 8" f/5 Newtonian well. It started to object when I tried a Mead 10" SCT. I was, by the way, very happy with the mount.

#9 brianb11213

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Posted 10 September 2012 - 02:29 AM

I also pondered the Duo-T. I keep reading good things about it and it has slo-mo controls. But I've also read the slo-mo controls can be hard to get to at times.

I have one (well the SkyTee 2 variety). Good solid mount, it will very likely be more solid than the tripod you put under it.

The slomo hand knobs can easily be removed and replaced by ones on flexible extensions - those that come with basic lightweight EQ mounts like the EQ1 fit, work well and should be available seperately.

#10 10gauge

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Posted 13 September 2012 - 08:44 PM

I looked at the Ioptron IEQ45 Modified as a quality alternative to the Atlas GEM with manual fine adjustment knobs for altitude and azimuth. I do like the fact that it's 10 lbs. lighter and can fit a Losmandy tripod. However, for the IEQ45 Modified, one review measured a PE of +-31.5 arc-sec and another review at +-11 arc-sec. Is the Ioptron an accurate tracking GEM compared to Atlas?

If I do AP in the future, I won't be using a computer, only a Canon 5D. This is because I'll be taking the scope and mount 80 miles away to darker skies almost every time. So I don't want to rely on PemPro for PEC if I don't have to...

If I have tracking errors, can one reduce the PE manually. How does PEC work?

#11 SkipW

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Posted 14 September 2012 - 05:14 PM

Before committing serious $$$ on a DM-6 or a T-Rex for my anticipated TEC140, I thought I'd pose a silly question: How can one use an Atlas or any GEM for that at matter, in any sort of practical alt-az capacity?

In other words, is there a way to disengage the gears of the GEM to allow free movement to sweep faster in both axes then engage the gears to track?

If so, is there any resistance to any weight imbalance to prevent the scope from falling to one side?

Thanks guys!


Oh, you can disengage the gears--by undoing the locks--and you can set latitude to zero, but the mount WILL NOT track in alt-az. It will only track in this setup if you move to the north or south poles. The answer? Wait for the Synta/Skywatcher AZ EQ-6 or look at one of the Ioptron mounts.

Actually, it will track in this setup only if you move to the equator (i.e. latitude zero)and point the polar axis at one of the poles. And, although it might work, as already noted, it would be kind of a wacky variant on Alt-Az.

To use this as a conventional Alt-Az, you have to point the polar axis straight up (as already pointed out). With this, it will track correctly only if you're at a pole

#12 Junn Chavez

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Posted 15 September 2012 - 02:46 PM

Check out the article by Greg Nowell in AMart "The Super Polaris Mount in Alt-Az Configuration, it might give you an idea.

Review tab > Mounts > Alt-Azimuth > The Super Polaris Mount in Alt-Az Configuration

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#13 10gauge

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Posted 15 September 2012 - 09:04 PM

Thanks Junn, That Super Polaris Mount looks well machined with fine adjustment controls and scales. Greg Nowell is very knowledgeable and his advice has always been helpful to me in earlier threads. I wonder if it is up to the task of supporting a TEC 140? In my search, I am wondering if there is a good mount that has BOTH slow motion controls AND motors and GoTo capability. Or is it only one and not the other? Is the Losmandy G11 as such?

It appears that the Vixen GPD2 mount replaced it. Vixen claims 35lbs capacity on the GPD2, I wonder if that's good for the TEC 140 with a Mark V Bino?

Thanks Guys!

#14 buaku

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Posted 18 September 2012 - 11:00 PM

I am not sure if it can handle 250x smoothly. Let us know how it works out in first light.


Well for me I highly doubt I could track 250x smoothly.
I finally got it out this morning and tonight and it works well enough for scanning the skies with a low power eyepiece, like my 32mm. Going to my 10mm (100x) it got hard to find things again and move smoothly.

I don't think I have it balanced very well. Then again I am using a newtonion so its not exactly symmetrical. It's funny how it seems to balance OK in the house, then I take it out and it's not balanced so well anymore...even starting with the eyepiece in it. It has the tendency to start to drift/flip over as I start to point it straight up.

Maybe it would work better with a refractor. One day I'll have to get my a nice 5" refractor.

I gotta say I really do like the craftsmanship of the mount though!

#15 Lee Jay

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Posted 19 September 2012 - 08:37 AM

Are there any reports on how good the Ioptron or SW AZ EQ-6 are?


I was under the impression that an Atlas is an EQ-6, and that an AZ EQ-6 is a modified version of an EQ-6. Thus, isn't it reasonable to expect that an AZ EQ-6 will perform about like an Atlas?






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