Exos 2 PMC 8 RA balance #TECHNICAL


Devesh Pande
 

Hello Everyone,

Yesterday was my first day with the EXOS 2 PMC8 mount. I setup ASI Air and now it's so easy to polar align and use the go-to function.

I have a Apertura 60mm EDR scope. I mounted a SVbony guidescope with ASI 462 MC camera as a guide camera on the top of the scope. A Nikon D 5500 is hooked to the field flattner. When I try to balance using the included counterweight (using only one) I am unable to balance with the counterweight being right at the top. Would a 5lb counterweight help in RA balancing? Also my Dec is completely unbalanced as well. I have a small vixen plate from apertura and I tried to move the scope back and forth on the saddle but Dec doesn't balance either. It falls to the right looking from polar scope side. Any tips?

Thanks in advance.

Devesh


Micheal
 

Deveshp1

   I have a 150 mm RC scope that I was able to mount the guide scope on the opposite side from the dec motor. I had to add some back to other side to get this to work. I would see if you can get a plate to mount on top of the scope that would allow you offset it to balance the dec motor with the guide scope. Then I would try a lighter weight for balance in the RA direction.  If it's close I would try 8 lbs. Experiment if you can first.

Micheal

On 12/14/2021 8:04 AM, deveshp1@... wrote:
Hello Everyone,

Yesterday was my first day with the EXOS 2 PMC8 mount. I setup ASI Air and now it's so easy to polar align and use the go-to function.

I have a Apertura 60mm EDR scope. I mounted a SVbony guidescope with ASI 462 MC camera as a guide camera on the top of the scope. A Nikon D 5500 is hooked to the field flattner. When I try to balance using the included counterweight (using only one) I am unable to balance with the counterweight being right at the top. Would a 5lb counterweight help in RA balancing? Also my Dec is completely unbalanced as well. I have a small vixen plate from apertura and I tried to move the scope back and forth on the saddle but Dec doesn't balance either. It falls to the right looking from polar scope side. Any tips?

Thanks in advance.

Devesh


Devesh Pande
 

Michael,

Thanks for your message. I have been trying real hard to balance the Dec but I just can't. I added the guidescope on the opposite side of the Dec motor but still it doesn't help. I am attaching a few photos and videos here. The scope just doesn't balance moving it forward or backwards.



--
EXOS 2 PMC 8
Aperture 60mm EDR
Apertura 1X field flattner
ZWO ASI Air
ZWO ASI472MC
Canon 60D
Celestron C8
Bortle 7


Stan
 

Hi Devesh,

>When I try to balance using the included counterweight (using only one) I am unable to balance 
I assume this is because the mount still tips towards the counterweight side, even with it at the top and not because the mount is stiff? If so, then you are correct, you will need a smaller counterweight. Looking at the specs, it looks like you have less than 10lbs of equipment and the CW is about 12lbs so will be too heavy. The good news is that you have a very lightweight setup! I think Michael's suggestion of 8lbs might work, but even that might be too heavy. My OTA assy (including cameras, and finders) is about 15lbs and I usually balance with the 12lb weight about halfway up the bar. If there is a way you could jerry-rig a weight temporarily to the bar you could run some tests. I have used water bottles strapped to the bar in a pinch!

>Dec doesn't balance either
Did you extend the dew shield fully? if it is heavy on the camera side, that might help. If that doesn't work, you need a longer vixen plate.

It has been reported here that for best guiding, you don't want the mount to be perfectly balanced. Instead it should be slightly unbalanced in RA so that the mount should be lifting some weight as it tracks. The same for DEC and of course the side that needs to be slightly heavier will change depending on the segment of sky you are pointing at. 

Good luck getting the rig up and running!


--
Mounts: ES EXOS2 PMC-8
Scopes: Skywatcher Evostar 120ED
Cameras:  iPhone, Lumix LX-7, SvBony 305
Misc:
Software: ExploreStars (windows and iPad), ASCOM, Stellarium, PS Align Pro, SharpCap


Devesh Pande
 

I was finally able to balance the rig minus the ASI air. I mounted the ASI air on the motor side and the rig won't balance. So to counter the motor weight, I decided to order a dual finder bracket and mount both the guidescope and ASI air on it.

For the RA balance, I ordered a 5 pound counterweight. I hope it works.

Stan,

Thanks for your message. I was able to mount my C8 and balance it with just one counterweight! Pic attached! How big of a weight can this mount take for good tracking? I am assuming my C8 with camera and guidescope should be around 15 lbs!

Doug,

Thanks for your help. I did move the camera forward with a longer vixen plate and it helped!

Devesh

--
EXOS 2 PMC 8
Aperture 60mm EDR
Apertura 1X field flattner
ZWO ASI Air
ZWO ASI472MC
Canon 60D
Celestron C8
Bortle 7


Harry
 

Devesh, 

Although I have the iExos 100 mount, my setup is very similar. I could not balance my ES ED 80CF scope with its short Vixen bar. So I added a longer Vixen bar (7 1/4”) and bolted it below the existing bar for an extension. It works great, although like you, you no longer are able to rotate the focuser as far because the extended Vixen bar interferes. I don’t find that a problem. You would probably need a 7-8 inch extension.

I believe you have too heavy a counter weight. With my carbon fiber scope, Nikon D5500, Hotech Field Flattener, ASIair Plus and ZWO guide camera/scope (mounted on a dual finder bracket) I use 3 ES 1kg counter weights, (6.6 lbs). It balances in both axis fine.

See attached photos.
--
Harry

Mounts: ES iExos 100-PMC Eight, ST3 Tripod

Scopes: ES  ED80CF, ES AR102,  Meade ETX 90 EC (Deforked)
Guide: ZWO 30mm Mini, ZWO ASI120MM-Mini
Software: ASIair Plus, iPad Pro, MacOS, Affinity Photo, SkySafari Plus
Cameras: ZWO 533MC Pro, Nikon D5500 (UV/IR Mod), D600
Misc: Rokinon 135mm F2 Lens, ES USB Power Bank

Filters:  Optolong L-Pro, L-eNhance






Wes Mcdonald
 

Devesh

You have far too much weight behind the DEC axis pivot point.  From the looks of it, you are going to have to get a super long dovetail and let it extend way back toward the camera, and clamp it in the saddle back there between the camera and back of the telescope tube.  

Wes.


--
Wes, Southport NC
EXos2-GT PMC-8, iExos 100, ESG11
ES ED 127+MoonLite Focuser, 10" LX200GPS+ MoonLite focuser+wedge, Astro-Tech 8" Newt, ETX-90, 60mm no-name guide scope ~ 260mm FL
Polemaster, Orion ST-80 and SAG, ZWO 290MM, D5300 astro modified, ASI071 cooled OSC, ASI MM290 guide camera
Nina, Bootcamped Mac Mini control computer, RDP to iMAC
110 amp hour lead acid deep discharge battery for field power
Electrical Engineer, Retired


Devesh Pande
 

Harry,

Thanks for your message. This is the exact setup I am thinking of. 

My scope is just 60mm so hoping the 4.4 lb counterweight from ioptron I got would suffice. Counterweights are so hard to find these days!

Devesh

--
EXOS 2 PMC 8
Aperture 60mm EDR
Apertura 1X field flattner
ZWO ASI Air
ZWO ASI472MC
Canon 60D
Celestron C8
Bortle 7


Micheal
 

Devesh

In the video you have the ASI Air and a white box on same side of the mount as the Dec Motor. You need to get these to the other side of the mount. This will help your balance some. You may need to move these for they are forward of the deck motor to get balance. After getting the ASI Air etc to other side see if you can reach balance without the field flattener, If you can you will need to use the ASI Air etc to balance the  the Dec motor and flattener by moving it forward more. I had to add a movable weight to the front of my RC scope below the scope about 3" off center line of slope.

Micheal

IExos-100 and EXOS2GT both running PMC-Eight version 20A01.
iOptron Photron 150mm RC OTA
Svbony 503 80mm f7 w/ Orion 0.8 field flattener
Celestron 150mm C6n f7 w/motor focuser controlled w/ FCUSB Motor Controller
Svbony 50 mm guide scope on 80mm Scope
Svbony 60 mm guide Scope on 150 mm Scope
Cameras Canon T7, ZWO 224, ZWO 120mm, ZWO 120 MC 
DewBuster controller for 2 temp controlled dew strips, plus up to 4 additional dew strips, It also is Powering my Canon T7 camera, a 7 port USB Power hub, and fan for the 150mm Scope.

ASCOM 6.5 sp1 with Device Hub. Cartes Du Ciel for mount control, SharpCap for Polar alignment and planetary photos, Astro Photography Tool, platesolve2, PHD2 for guiding, and Stellarium for object framing only.

On 12/14/2021 3:13 PM, Devesh Pande wrote:
Michael,

Thanks for your message. I have been trying real hard to balance the Dec but I just can't. I added the guidescope on the opposite side of the Dec motor but still it doesn't help. I am attaching a few photos and videos here. The scope just doesn't balance moving it forward or backwards.



--
EXOS 2 PMC 8
Aperture 60mm EDR
Apertura 1X field flattner
ZWO ASI Air
ZWO ASI472MC
Canon 60D
Celestron C8
Bortle 7


Devesh Pande
 

Hello Micheal,

What kind of movable weight did you get? I have the guidescope and camera on the opposite side of the Dec motor but it is placed on the scope. See attached photo. I am still unable to reach balance.

Thanks,
Devesh

--
EXOS 2 PMC 8
Aperture 60mm EDR
Apertura 1X field flattner
ZWO ASI Air
ZWO ASI472MC
Canon 60D
Celestron C8
Bortle 7


Micheal
 

Devesh

     I'm somewhat of a wood worker.

    I used a block of  wood (oak) 1 1/2"x1 3/4"x3 1/2" that I Drilled two hole through at 90 deg two each other. One I drilled through the centre just over a 1/4" dia. centred on the 1 1/4" side that I then attached to the bottom of the full length mounting plate on my RC scope. I then drilled a hole just in front of this hole in the 1 3/4" dimension that's (90 deg) just under 5/16" diameter for I could thread a 5/16" rod through the block of wood. I let the rod cut it's own threads in the wood block. Then I experimented with 1 1/2" dia. plate washer clamped  between 2 wood Nuts. This let's me screw the weights back and forth from the block and add or subtract washers. It was fast and dirty and worked. Hope to redo it with metal block. Most likely just paint the wood black. I wanted it very adjustable because I'm planing on adding a focuser motor and this will change the balance again. See Pictures. I was very surprises that with the guide scope on the opposite from the Dec. I needed to add the weight to the same side as the dec. motor.

On 1/1/2022 9:42 AM, Devesh Pande wrote:
Hello Micheal,

What kind of movable weight did you get? I have the guidescope and camera on the opposite side of the Dec motor but it is placed on the scope. See attached photo. I am still unable to reach balance.

Thanks,
Devesh

--
EXOS 2 PMC 8
Aperture 60mm EDR
Apertura 1X field flattner
ZWO ASI Air
ZWO ASI472MC
Canon 60D
Celestron C8
Bortle 7


Devesh Pande
 

Sorry for the late response. My 2 year toddler has been keeping me busy and the weather in Michigan hasn't helped either. 

I had a spare camera mounting plate and a ball head lying around. So I added it to the front of my dovetail Plate. Now it balances perfectly.

My RA axis though seems a bit stiff. Not sure if it is the cold weather but it's. Not as 'buttery smooth' as DEC. I haven't tried mount C8 though. Unsure if the 'lightness' of my current setup is causing this.
--
EXOS 2 PMC 8
Aperture 60mm EDR
Apertura 1X field flattner
ZWO ASI Air
ZWO ASI472MC
Nikon D5500a
Celestron C8
Bortle 7


Micheal
 

Devesh

   Nice solution. 

   I've notice that my RA axis is a bit stiff when cold the other night also. It was -12 below the last time  here in Minnesota last time i was out. Wasn't able to guide due to camera problems but was able to take 60sec exposure for 2 hr with out adjusting mount pointing.

Micheal

Exos-100 and EXOS2GT both running PMC-Eight version 20A01.
iOptron Photron 150mm RC OTA
Svbony 503 80mm f7 w/ Orion 0.8 field flattener
Celestron 150mm C6n f7 w/motor focuser controlled w/ FCUSB Motor Controller
Svbony 50 mm guide scope on 80mm Scope
Svbony 60 mm guide Scope on 150 mm Scope
Cameras Canon T7, ZWO 224, ZWO 120mm, ZWO 120 MC 
DewBuster controller for 2 temp controlled dew strips, plus up to 4 additional dew strips, It also is Powering my Canon T7 camera, a 7 port USB Power hub, and fan for the 150mm Scope.

ASCOM 6.5 sp1 with Device Hub. Cartes Du Ciel for mount control, SharpCap for Polar alignment and planetary photos, Astro Photography Tool, platesolve2, PHD2 for guiding, and Stellarium for object framing only.

1/14/2022 8:15 PM, Devesh Pande wrote:

Sorry for the late response. My 2 year toddler has been keeping me busy and the weather in Michigan hasn't helped either. 

I had a spare camera mounting plate and a ball head lying around. So I added it to the front of my dovetail Plate. Now it balances perfectly.

My RA axis though seems a bit stiff. Not sure if it is the cold weather but it's. Not as 'buttery smooth' as DEC. I haven't tried mount C8 though. Unsure if the 'lightness' of my current setup is causing this.
--
EXOS 2 PMC 8
Aperture 60mm EDR
Apertura 1X field flattner
ZWO ASI Air
ZWO ASI472MC
Nikon D5500a
Celestron C8
Bortle 7