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Old 20-09-2021, 09:42 AM
pan_ik (Nick)
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HEQ5 and 8" Newt - Counterweighting

Hi All,

New to the Astrophotography hobby. Have had smaller GOTO MAK's over the years but after moving away from Sydney to the Mountains, I finally invested in a decent mount and was playing around with just my D7000 + 210mm lens, with a 60mm GuideScope + ASI120MM-S.

Researched the weight limits on the HEQ5 during lockdown and wanting to show my wife the planets, and maybe pick out some more faint DSO's, suffice to say I think I may have been overexcited, I purchased a 200mm Newt to mount on the HEQ5. Tests on the Moon, plus Jupiter and Saturn went great. Best I have ever seen them through my own gear!

However I've found than even with both weights fully extended, if the object is close or just over the meridian, she goes over the rest of the way. luckily both times I have been just next to the scope running a plate solve so was able to catch and turn off the mount quickly.

Am I overloading the HEQ5? OTA is 8.75Kg, plus 780g for the D7000. Around the same again for the Guide + ASI120MM-S.

Can you purchase extending poles for the counterweights? Part of me thinks I should have instead waited for a APO Refractor for Astrophotography and a MAK for my wifes viewing pleasure? I have seen great images from similar sized Newtonians, but I can't really upgrade the mount anytime soon, so thinking I would switch it over to a non tracking for just visual, and stick with the light camera and lens for photos.

Appreciate any advice.
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Old 20-09-2021, 10:15 AM
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pmrid (Peter)
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Nick, your HEQ5 should be able to handle a 10 KG load for imaging and up to 15 KGs for visual. I dont really follow what you mean about the meridian. Could you explain more fully? My first impression was that your weights were sliding up and down the weight bar. Is that it?
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Old 20-09-2021, 11:14 AM
raymo
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The two 5kg weights are not quite enough to balance your payload. You can
get extensions, but it is better for the mount to add a 1kg weight. You can press anything into service temporarily. You can gain a little effective weight,
maybe enough. You will see that one side of the 5kg weight is recessed around the central hole. If you put the weight on with the recess toward the
free end of the shaft and slide the weight down so that the screw in weight
retainer is inside the weight, you gain a little effective weight.
A scope will not stay where you put it [if properly balanced] if you loosen the RA clutch, because the scope should be balanced a little against the drive direction in order to keep the drive gears fully meshed.
Regarding the meridian business, if the RA clutch is nipped, up the scope shouldn't be able to go anywhere, apart from taking up any backlash in the gears, as it goes over the top and starts coming down the other side, so I also don't understand what you mean.
raymo

Last edited by raymo; 20-09-2021 at 11:21 AM. Reason: more text
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Old 20-09-2021, 11:37 AM
pan_ik (Nick)
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Hi Guys, thanks for the feedback.

If you imagine the RA like a clock, as the scope tracks east to west, once it passes the 12 O'Clock position and starts moving towards 11, I have twice seen the scope continue on its merry way towards 6pm at an increased rate. RA Clutch is nice and tight.

I have only seen this with the Newtonian, with my camera setup all has been fine. Thats why I was wondering if I am overloading it, or if simply adding more counterweight will fix this.

Last edited by pan_ik; 20-09-2021 at 11:39 AM. Reason: more explaining.
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Old 20-09-2021, 04:39 PM
Mickoid (Michael)
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Nick, I sometimes use the same set up that you have for planetary photography. Balancing a largish Newtonian with camera attached can be real tricky and you can have it balanced in one position only to find it horribly unbalanced in another. I have found, like Raymo has mentioned, the addition of a 1-1.5kg weight will help balance the scope. You can add a weight from a dumbbell that can be purchased separately from a sports store. I have a 1.25kg one that I sandwich between the two 5kg weights and like Raymo said, to give the weights a little more extension along the shaft, make sure you place the end one on the shaft so that the retaining knurled nut can sit in its recess. I'd steer clear of using a shaft extension to increase counter weight, it puts a fair bit of strain on the joint of the shaft closest to the mount. Try to have your scope balanced in the position it will be in when pointing at the object you'll be viewing/photographing.
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Old 20-09-2021, 04:55 PM
Startrek (Martin)
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Attached is how I balance my imaging newts 6 and 8 solid tube OTAs
My 8 f5 newt with all AP gear has a payload of nearly 15kgs on an EQ6-R pro mount . I use 3 x 5 kg counterweights and a 180mm extension shaft. The counterweights sit only about 50mm past the join.

Cheers
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Old 20-09-2021, 06:11 PM
RyanJones
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If you are using the scope for AP you can turn the OTA so that the focuser faces downwards. This positions the weight of the camera closer to the RA axis thus reducing the distance the counterweights need to be from the RA axis ( or the need for extra weight ). As far as the scope continuing beyond the meridian goes, unless your clutch is loose this is not going to due to overloading. Id be watching to see if your mounts power indicator light is flashing when it is slewing. The additional weight of your Newt will have greater current draw and could be causing the voltage from you power supply to drop enough to confuse the Synscan hand controller. Id be upgrading the power supply ( or making sure it has enough current supply ) as my first port of call.

Hope this helps

Ryan
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Old 21-09-2021, 07:20 AM
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pmrid (Peter)
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Quote:
Originally Posted by pan_ik View Post
Hi Guys, thanks for the feedback.

If you imagine the RA like a clock, as the scope tracks east to west, once it passes the 12 O'Clock position and starts moving towards 11, I have twice seen the scope continue on its merry way towards 6pm at an increased rate. RA Clutch is nice and tight.

I have only seen this with the Newtonian, with my camera setup all has been fine. Thats why I was wondering if I am overloading it, or if simply adding more counterweight will fix this.
I have trouble imagining how this might occur. Before I attempt a diagnosis, let me ask one more question. Does your Dec axis also spin around in the same way?

i am beginning to wonder whether the worm gears or the spur gears are adequately tightened.

My instinct is to suggest you contact a local IIS member and ask them to take a look.
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Old 22-09-2021, 08:42 AM
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Sunfish (Ray)
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I agree with Peter and Raymo. An additional 1 kg weight to the two 5kg is all that is needed to balance the 8inch newt and camera on the HeQ5. That is what I use .

The mount should not shift or move suddenly unless what you are seeing is the beginning of an automatic meridian flip. The dovetail clamp on top of a heq5 can come loose if the grub screws are not tight but that does not sound like your problem.
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Old 14-10-2021, 11:13 AM
jahnpahwa (JP)
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I'll chime in here and say that additional weight is unnecessary.


I too used an extra weight sandwiched between standard weights, but then rotated the OTA so that the camera and guide scope straddled 6o'clock (straight down)... the camera should be slightly closer to 6 o'clock than the guidescope and guidecam as it is (mine is) slightly heavier.


I have an heq5, skywatcher PDS 200 (8" F5 newt), SW evoguide 50, ZWO guide cam and either a ZWO1600 with filter wheel, or recently a canon 5D with battery grip, all no worries. The 5D, I suppose, is a chunk heavier than your Nikon. Counterweights are one about 5mm away from the end, the other about an inch separated.



Definitely better (I think) to perfectly balance weight closer to the axis of rotation. The body of 5D is not far off the RA axis at all with this configuration.

Last edited by jahnpahwa; 14-10-2021 at 11:29 AM.
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Old 14-10-2021, 07:54 PM
echocae (Brian)
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I am using heq5 that recently undergo Hypertuning as I used em for Astrophotos

I can vouch.. hypertuning is great not only great guiding, it is able to utilised its payload to the MAX ( and can over the stated limit , I used em to around 15-17kg fully loaded).

200PDS is nothing with hypertuning , only down side is 200pds focusser may be not so good to handle heavy gear (camera, filter, oag, etc....)
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