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TEC140 on a GM-8?

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#1 AZStarGuy

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Posted 11 April 2010 - 06:02 PM

For strictly visual? Or would I be kicking myself that I didn't save longer and get the G-11?

2 things I question a little. The tripod looks so-so in the pics I've seen and the saddle looks a little short. There are no stocking dealers in AZ though so I can't see one in person to get a better feel.

The OTA is roughly 19 lbs. Figure in 2" Diagonal, Rings, Plate and my heaviest EP (2.25 lbs) and it might total 26 - 27 lbs...?

I keep looking at the Atlas EQ-G but something's holding me back. I think I'm in love with the machining on the Losmandys.

Thoughts?

#2 Charlie Hein

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Posted 11 April 2010 - 06:05 PM

I would personally be much happier with the 140 on the G-11.

#3 RAKing

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Posted 11 April 2010 - 06:09 PM

I used a GM-8 to carry my TMB 130 (25 pounds) and it was okay for visual - but I used an Astro-Physics Portable Pier for main support. The mount is fine (and that machine work is beautiful :cool:), but I think the standard tripod that comes with this mount is a little light.

Bigger is always better and I eventually replaced the GM-8 with a Mach 1.

Ron

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#4 Jeff B

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Posted 11 April 2010 - 10:09 PM

GM8 will do just fine.

It handles my MN76, 6" F10 Achro and my Intes M815 just fine so the TEC 140 will be no sweat.

The GM8's my most used mount.

Jeff

#5 AZStarGuy

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Posted 12 April 2010 - 07:56 AM

Wow that AP pier is nice! The TMB is the other scope I'm considering. That's a really really nice setup!

Jeff: you have a 6" F10 achro on the 8? Are you using the standard tripod.

I suppose if that becomes a weak point, I coulb buy a used G11 tripod since it's direct fit or keep an eye out for the AP etc stuff.

#6 TomN

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Posted 12 April 2010 - 07:59 AM

My AP130 works fine even on the Great Polaris...but I prefer the G11. The G11 tripod is massive and stable so should be all you need to help that G8 work well though...

#7 hfjacinto

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Posted 12 April 2010 - 08:15 AM

At Jenny Jump one of the guys has a TEC on a Siruis Mount and he wants the G11, its not that it isn't good on the Sirius but because of its length vibrations affect the mount more than a squat tube like a SCT.

#8 RAKing

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Posted 12 April 2010 - 08:53 AM

Wow that AP pier is nice! The TMB is the other scope I'm considering. That's a really really nice setup!

Jeff: you have a 6" F10 achro on the 8? Are you using the standard tripod.

I suppose if that becomes a weak point, I coulb buy a used G11 tripod since it's direct fit or keep an eye out for the AP etc stuff.


Thanks, Ron. I do miss my TMB - it is a great scope. But you will probably like the 140 just a little better. Aperture does count. :)

I now use my Mach 1 on a G-11 tripod. As mentioned above, it is very stable plus I can adjust the height for my different scopes.

Ron

#9 skyward_eyes

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Posted 12 April 2010 - 02:35 PM

Id go with a TEC140 on a CGEM honestly. Got to use one at the Messier Marathon a month ago and it was a perfect match!

If you go with a Losmandy I would go with the G-11, it would allow you to push to higher powers without issues and wont be near as shaky.

#10 Jeff B

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Posted 12 April 2010 - 07:04 PM

Jeff: you have a 6" F10 achro on the 8? Are you using the standard tripod.

I suppose if that becomes a weak point, I coulb buy a used G11 tripod since it's direct fit or keep an eye out for the AP etc stuff.


Yes, you are correct in that, when fully extended, the tripod is the weakest link. However, for visual use it's still quite acceptable. For example, My 6" F10 Achromat weighs in at ~29 pounds when dressed to kill (rings, finders, counterpoise weights, diagonal AND bino viewer). There is vibration (ALL scopes/mounts have it to some degree)but it's lower in frequency, low amplitude and thus focusing at high power is no problem. With the finger tap test vibrations damped out in less than a second. The TEC should be "inside the envelope" of my 6" F10 achro in terms of size and mass, therefore I would expect even slightly better results than my experience.

The G11 tripod does indeed make a good improvement, especially with the 6" F10 as I can use the pier extension (not recommended with the G8 and heavier loads) to keep my butt off of the ground when viewing at zeinth. A good price for a used one is ~$300.

A larger mount is usually better. I said usually. My experience for visual use is to that you can actually have a harder time focusing at high magnification with a stiffer set up as the natural frequency of the vibrations that do exist are higher and the eye & brain can have a hard time with that. That being said, I also LOVE my G11 and GM-100 mounts and can certainly recommend them. The G8 however, is much easier to haul around and set up than the bigger mounts. If I'm feeling frisky, I'll take the G8 head and three 7 pound counterweights out as one unit, something that's not possible with the G11.

Price wise a good used non-Gemini GM-8 should go for about ~$1000-1100 and $1700-1800 with Gemini L4. A good use non-Gemini G11 comes in at ~$1700-1800 and add $900-1100 for Gemini (I don't know why but a used Gemini system is cheaper with a G8...go figure).

I hope this helps you out...or stirs up the indecision pot again. :grin:

Jeff

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#11 Jeff B

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Posted 12 April 2010 - 07:06 PM

A different application for the G8

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#12 Jeff B

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Posted 12 April 2010 - 07:08 PM

And another. As I said, it's my workhorse mount.

Jeff

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#13 guyinthesky

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Posted 12 April 2010 - 08:05 PM

i think it will be fine. i just got a gm-8 2 weeks ago and i use my c9.25 (22lbs i think) on it and can do 4 minute exposures nice and round stars with only using the polar alignment scope because i have not learned to drift align yet. im buying a tec 140 slightly used this saturday and im excited.. nice choice, high five ! i think with any hobby when you buy somthing you always wished you went onesize bigger. i was thinking atlas or cgem, but i bought the losmandy gemini .although it doesnt handle as much weight, i feel i went one bigger because of its higher quality.

#14 AZStarGuy

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Posted 13 April 2010 - 08:04 AM

Wow. I can't believe what some of you have on the GM-8. Those are some sweet scopes BTW.






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