I have a Meade LX70 R5 120mm f/8.3 that I use on my LXD75 EQ mount which carries it well. I am contemplating getting an alt/az mount like a Vixen Porta II Tall Plus. This OTA is about 12.5 lbs. with rings, bar, Telrad, eyepiece, etc. and it is pretty long, so the moment arm is significant. Any suggestions or advice on this particular mount, or something similar in price, are welcome, especially if you have or have had an OTA this size. Thanks everyone in advance.

Alt/Az Mount for a 120mm f/8.3
#1
Posted 02 December 2019 - 06:32 PM
#2
Posted 02 December 2019 - 06:54 PM
I really like my Stellarvue M2C with guide handle and mount extension.
It is mounted on an Oberwerk (or similar) wooden tripod.
This combo will easily support this scope (have the same one) and will allow more clearance when observing higher altitudes towards the zenith. It is more costly but well worth the $.
- paul m schofield likes this
#3
Posted 02 December 2019 - 07:06 PM
+1 for the M2C. I mount mine on the AVX tripod and it's a very sturdy combination.
- joseph07081 and paul m schofield like this
#4
Posted 02 December 2019 - 07:18 PM
The M2C head will work great with the scope. You can use the Lx70 tripod you have already
- paul m schofield likes this
#5
Posted 02 December 2019 - 08:18 PM
MC2 seems to be the only one there to work. I once hooked my 120 F/8.3 to an AZ4... let’s just say this, good for keeping it low power, but realistically, would never recommend it. The Porta is more than likely well out of the question.
- punk35 and paul m schofield like this
#7
Posted 03 December 2019 - 05:42 AM
I have a Meade LX70 R5 120mm f/8.3 that I use on my LXD75 EQ mount which carries it well. I am contemplating getting an alt/az mount like a Vixen Porta II Tall Plus. This OTA is about 12.5 lbs. with rings, bar, Telrad, eyepiece, etc. and it is pretty long, so the moment arm is significant. Any suggestions or advice on this particular mount, or something similar in price, are welcome, especially if you have or have had an OTA this size. Thanks everyone in advance.
This scope is a little lighter but longer than the 120mm F/7.5 ED scopes like my Orion Eon.
I much prefer slow motion controls on an alt-az mount, they let me track at high magnifications and center precisely. Ideally the "tension" can be adjusted on the fly to help with balance and manual slewing.
I had 120mm F/8.3 for a while and used it with the same mount I use with the 120 EON. It's StellarVue MG-2. It is solid and does the job. Last night I had the Eon up to 375x and it was solid.
- paul m schofield likes this
#8
Posted 03 December 2019 - 12:38 PM
Another vote for the M2C, I have one on my AVX tripod and it is solid.
- paul m schofield likes this
#9
Posted 03 December 2019 - 01:03 PM
Thanks everyone for your replies. It's becoming obvious that the Porta II type mounts aren't up to the size of the 120mm f/8.3 OTA's. I'll continue to use mine on my LXD75 mount as I know it can carry it.
- Jon Isaacs likes this
#10
Posted 03 December 2019 - 01:11 PM
Thanks everyone for your replies. It's becoming obvious that the Porta II type mounts aren't up to the size of the 120mm f/8.3 OTA's. I'll continue to use mine on my LXD75 mount as I know it can carry it.
I have used my 8.3 120 mm on my AZ8 with success. Might be more than you want to spend though.
Cheers!
JMD
- paul m schofield likes this
#11
Posted 03 December 2019 - 02:12 PM
I'd agree with JMD. Once the scope gets over 4 inches, I prefer something heavier like the Losmandy AZ8. The scope shown is an AT115EDT (ƒ7) which weighs 16 pounds and averages over 40 inches with accessories. The home brew counterweight is helpful when regulating balance as eyepiece weight changes.
- niteskystargazer, paul m schofield, MGD and 1 other like this
#12
Posted 03 December 2019 - 08:05 PM
I will add my voice to those suggesting the Stellarvue M2C. IMHO, the best value to be found mid-size, alt-az mounts. It performs well above its price range.
Edited by NC Startrekker, 03 December 2019 - 08:06 PM.
- paul m schofield and desertlens like this
#13
Posted 03 December 2019 - 08:52 PM
And one cool thing that hasn't been mentioned here is that you can add encoders and Nexus stuff to the Stellarvue M2C and that turns it into a very nice and accurate push-to. You get the M2C, whenever you come up with a few hundred more $$ you add encoders and have one of the nicest, solid, systems you can get. That also probably applies to some other referenced mounts.
- NC Startrekker and paul m schofield like this