开云体育

  1. Losmandy_users
  2. Topics

East-Heavy Guiding With G11T?

 

I just received an axis upgrade for the G11T. Travel, poor weather, and stuff still coming in for my imaging setup will prevent me from putting everything through its paces. For G11T (with Titan RA axis) users out there, do you guide east heavy with this mount? I realize experiences may differ, but I'm wondering whether or not some or most users see guiding improvement this way specifically in RA.?
?
Regards,?
?
George
 

Hey George,
I'm not a G11T user but I do use East-Heavy with my G11G and I have noticed an improvement in general. I had an ADM balancing weight with a vixen clamp and I 3D printed a sleeve that clamps around my DEC Axis around the polar-scope area. The East side has a vixen shaped part that the clamp can attach to. I've noticed that a near perfect balance in RA and DEC results in a little less RA chatter during guiding and my guiding seems to have gotten a little more consistent with my 10" newt.

Sorry I'm not answering your direct question, as I don't have a G11T, but just wanted to offer one solution. Hope you don't mind. I can only imagine the G11T would also benefit from this without the spring loaded worm.

Another option that was recommended by Michael Herman included a loop of rope around the RA EXT knob on the west side that wraps over the top of the RA EXT and down the left side of the mount. At the bottom of that rope is a hanging weight that puts a constant pressure on the East side of the RA axis. I'll see if I can drum up a photo.
 

On Mon, Nov 18, 2024 at 10:42 PM, George Stallings wrote:
I just received an axis upgrade for the G11T. Travel, poor weather, and stuff still coming in for my imaging setup will prevent me from putting everything through its paces. For G11T (with Titan RA axis) users out there, do you guide east heavy with this mount? I realize experiences may differ, but I'm wondering whether or not some or most users see guiding improvement this way specifically in RA.?
Hi George,
?
A little East-heavy balance is needed with most non-spring-loaded worm/gear mounts (including G11T). This is because the worm and the gear can't be meshed too tightly in such a system, as that results in binding and motor stalls.
?
Since there must be some distance left between the worm and the gear, the gear has room to float just a tiny bit between the worm teeth (this is also the cause of backlash). With a perfectly balanced RA axis, the gear can shift from engaging one side of the worm groove to the other. Slight wind, slight cable drag, etc. can all cause a sudden jump in the gear position. In the image below, the gear tooth can jump from engaging the left side of the worm groove to the right with no resistance.
?
?
A slight East-heavy balance in RA pushes the gear into one side of the worm groove that drives the gear forward, while tracking. This imbalance produces the resistance needed to stop the gear from free-floating that can cause random jumps during tracking and guiding.
?
Regards,
?
? ?-Paul
?
 
Edited

Thank you both Paul and Ryan.?
?
Thinking this through, the easiest thing for me to do would be to just slide the counterweight down on the east of the meridian and slide it up on the west. To make the process fast, I can measure where these positions should be on the counterweight bar. I have the mount in an observatory in my backyard and have never purposefully gone to sleep while imaging. I sit on the couch, watch television, and monitor subs as they come in. I actually love doing this. Adding about 4 minutes to the process of walking out to the observatory to adjust a counterweight after a meridian flip will not be the end of the world.?
?
Of course, a longer-term solution that does not depend on my being able to stay awake at night watching streaming shows would be a counterweight acting specifically on one side of the RA like Ryan has done. This could also work for the G11T and I have an extra 3.5 lbs counterweight from ADM that would work well here.?
?
Ryan, do you happen to have the stl for that sleeve you printed to hold the counterweight??
?
Regards,?
?
George
 

Hey George,
Happy to share: here is the .3mf file from my Bambu P1S, but I also am attaching the STL exported from Fusion 360.
?
I printed it out of PLA at 100% fill, but I'm sure you could go with a lower fill setting if you wanted. I used a 35mm M5 hex bolt and nut but I believe a standard10-32 bolt would work as well.
Additionally, you can add a layer of felt to the inside if you want to protect the DEC axis a little more.
?
Let me know if you have any questions, ?and hope it helps!
?
Ryan

G11 East-Heavy Weight v4.stl
G11 East-Heavy Weight v4.stl
Eastern-Heavy Weight mount.3mf
Eastern-Heavy Weight mount.3mf

 

This is fantastic. I'll be printing this tonight. Thank you!!!
?
Regards,?
?
George
 

My previous long time strategy had been to use 3x 1lb threaded weights that thread into each other like a stack of pancakes and then threaded to end of CW shaft in place of toe-saver bolt. ?I found these at “ScopeStuff.com”
?
I balanced the mount with 2 weights attached. Then, depending on which side of meridian was imaging on, i would operate with either 1 or 3 weights in place by removing or replacing the outer two
?
I stopped using this technique after setting up automated meridian flips. I now have spring loaded worm so hopefully will not be needed as much. ?To be seen when all of my stuff comes out of storage next year.
?
?
--
Edward
 

Yes. ?I bias the load a small amount to the east and I see a clear difference on my G11T. ?Does not need to be much. ?Just a few lbs shifted to the east.?
?
JMD
 

I have to say, thus far, I haven't had to use east-heavy guiding, though I am set up in case this becomes necessary. This was more than an axis upgrade - I changed my entire imaging setup from an AT115EDT refractor reduced to F/4.5 to C11 Edge with F/7 reducer. I'm still rewiring the observatory. Clouds have slowed everything up.?
?
In the short time I've been able to use it though, the RA axis upgrade has proven to be a dream. After PEC training and PHD2 calibration, the mount guides as beautifully as I had hoped for. Over two sessions of about 3 hours each, my RMS values in relatively poor seeing were 0.34" for RA and 0.33" for Dec and 0.50" for RA and 0.42" for Dec. The second set of figures were for a DSO between 30 and 45 degrees in apparent elevation. For the first values set, it had risen above 50 degrees. I should not have been imaging on either night, but I cannot be too picky with my seeing options this winter. I've become a cheap date. My stars at 2000mm focal length (2008 according to platesolve) for subs from both imaging runs are round to the corners of my admittedly small sensor (IMX 533). These aren't as low as the numbers I've seen from the insanely expensive mount crew, but I hadn't seen anything that low in my previous experiences with any mount.?
?
I guess the best review of my short experience thus far is that I typically actively check each sub and PHD2 while imaging. While imaging last night, I realized at a certain point that I had stopped obsessively checking my PHD2 guiding graph. I was doing research for cloud monitors, looking for reviews for good NINA plugins, streaming a show on Netflix as subs came in every couple of minutes.??
 

Glad to hear it is working for you! ?It is a great mount! ?
?
JMD
 

I just want to second George’s reply, as I too have a perfect balance on my G11T. Granted, it’s sporting a RASA 11 v1 at the moment, but I’ve seen (and have the screenshots!) total RMS as low as 0.12” without pec (still haven’t got that right) on good nights. Typical garbage guiding is around 0.3” up to 0.5” if guiding with thin clouds passing through.
?
I’ve actually seen PHD2 charts of over a minute without a single correction (0.5” exposures).?

Guide cam is a ASI178mm, 4x Bin (I refuse to lose stars).
?
I use PHD2’s PEC RA algo and started using Limit Switch for Dec after seeing a video by the legend himself, Brian V.
?
My trick is minimal maintenance. Must be the crushed exoskeletons smoothing out the tracking.

1 - 11 of 11