Stargazer New Member
- Skill Level
- Time with Product
May 7, 2008
- User Notes:
Fine craftsmanship; Excellent tracking; Ease of useCons:
No PEC memoryComments:
I have used different makes of GEMs and my biggest problem has always been fiddling with the clutch locking knobs to move the mount in either right ascension or declination. This can be a real pain in the neck...literally!
Of course, if you're using go-to, you don't necessarily have to lock and unlock the clutches. Just line everything up and push some buttons. But I'm not a go-to guy.
The GM8 has a unique system that allows movement in both axes without unlocking the clutches. What a breeze! Turn on the 12 volt controller, find your target and enjoy the views while the GM8 tracks flawlessly. Want to move to another target? No problem. Use the adequate setting circles to swing the mount to the new area. All this without messing with those pesky clutch locks.
I use my GM8 permanently mounted in a small observatory for imaging with a Megrez 110 and a Canon DSLR. It has been drift aligned and I have never used autoguiding. The time exposures are normally around 120 to 180 seconds and 95% (approximately 19 out of 20) of the raw images show no sign of tracking errors. There is a routine for Periodic Error Correction (PEC) but I find it too time consuming. It has to be set for every session, as there is no memory. (I believe that the G11 has the PEC memory...but I'm not sure).
I have never done anything to the gears for improvement. I'm happy the way they are and believe in the old adage "if it ain't broke...don't fix it!" The build quality of this mount is excellent and the standard controls have several choices for tracking rates - Sidereal, Moon, Sun, etc. The control box also has a dimmer button to adjust the intensity of the control lights (very nice for keeping your dark adjusted vision). The hand paddle has a nice feature that I find very useful. While pushing a directional arrow button to move an object in RA or Dec, you can speed the movement by simultaneously pushing the corresponding button.
I'm very happy with the GM8 and even though it's more expensive than other GEMs that will carry the same weight, I feel that it is well worth the investment.
nam2525 New Member
- Skill Level
- Time with Product
May 1, 2007
- User Notes:
Excellent quality, Excellent features, PriceyPros:
Extremely high quality, reliable, Excellent trackingCons:
Pricey, GOTO "upgrade" is as much as basic version alone.Comments:
I have been using my GM-8 for more than 2 years now, and am very happy with it. One of the biggest advantages is you don't have to fumble with locks to disengage the motor to be able to move the scope by hand. This is a HUGE advantage in convenience over other less expensive models. BUT, if you are doing astrophotography with one of those other mounts, then you can always disengage the motors, find the target, and then engage the motors and use the hand control to adjust your aim and center the target. It's a bit more of a hassle, but it does work. However, with the Losmandy, you DON"T have to worry about being tired and forgetting to disengage the motor before moving it manually, thereby causing damage to the mount! This, as I said, is a huge advantage with the Losmandy design.
The mount is VERY stable. This is also a HUGE advantage over some of the less expensive mounts, but again if you choose one of those other mounts, then just get a small scope and you will be set. The Losmandy is rated for 30 pounds, I believe, and the usual recommendation is to only load a mount to half is rated capacity to help maintain stability. However, I have gotten great images with a 20-pound load in telescopes alone, not including counter weights (I am not sure if the counterweights count against the load capacity or not).
The build quality is extremely high, and it is generally regarded as the best mid-capacity mount available (there are better mounts by Astro-Physics, but those cost quite a bit and are hard to find). The GM-8 does cost $1500, which is FIVE TIMES the price of the basic Orion Sky View Pro middle-to-low-capacity mount, and ALMOST DOUBLE the price of the Orion Sirius EQ-G middle capacity mount. Many people have produced good results with these cheaper mounts, but the Losmandy requires little to no tweaking to get the best out of it, and it should last a very long time. I did adjust the worm bearing blocks on mine to help improve tracking, but this was fairly easy to do and only needed to be done once.
The mount tracks very well on its own, and now that I have started using autoguiding, it tracks even better! :) I have not really tried the Periodic Error Correction....this is a useful feature that helps you "train" the mount to overcome the slight errors it has (all mounts with gears will have some error). My advice is to use autoguiding, which will pretty much eliminate any worries about tracking (although this mount tracks very well to begin with!!)
If you get the Gemini GOTO version, it is $2500, but if you wait and try to upgrade to Gemini later, the upgrade kit is $1500!!! If you want GOTO, get the GM-8 with Gemini at the time of purchase and save $500!
I personally use the Digital Setting Circles (with Sky Commander....altogether about $600 worth of upgrades) which does help find targets quicker. I have also added the polar alignment scope (which is $150), and this does help in getting a pretty good alignment, and is especially useful if you will be dragging the mount out to use, and then storing in the house when not in use. However, if you plan on putting this mount in some kind of observatory or leaving it in place, then just drift align and don't bother with the polar scope. (one trick is to set it up on concrete or ashphalt, or landscape blocks in the backyard, find good polar alignment, and then make marks on the hard surface....then you can just align the tripod on the marks anytime you want to use it...this should work pretty well)
The Digital Setting Circles do have EXPOSED GEARS, and these have the potential to pinch you or any wiring near the gears if not careful....although I have not really found this to be a problem. You can get gear covers, but these are $75, which seems a bit unfair.
To sum up, this is a very high quality mount that is a bit pricey, but you will be very happy with its performance and reliability. If you can afford one and it will handle the load of your scope, then by all means buy one.Sort by