Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

sgl_imaging_challenge_banner_supernovae_remnants_winners.thumb.jpg.a13d54fa405efa94ed30e7abd590ee55.jpg

Astro Buer

Problems Counter Balancing the Sky Watcher Star Adventurer

Recommended Posts

Hi,

I will be the first to admit I'm a complete novice when it comes to equatorial mounts but I am hoping to find the advice I need on here as scouring the net for the last few days has brought me no joy.

I recently bought a Sky Watcher Star Adventurer Mount with the Astro Bundle (equatorial wedge, mounting plate, 1KG counter weight and shaft)

I am primarily going to use this for wide field as this is what the product does best, but one of the reasons I bought the Adventurer is that it is advertised as being able to handle a 5KG payload, and as I also own a Sigma 150-600mm lens I was hoping to be able to mount this and crack at shooting at longer focal lengths. I don't expect the results to be amazing, and I do expect to throw a lot of the subs away! but I still want to give it a try.

My setup entails:

Sony A7R2 - 625g

Sigma 150-600 - 1930g

Manfrotto XPRO Ball Head - 500g

Plus mounting bracket for Star Adventurer 

All in all this weighs in at just over 3kg, so tops 3.5kg with bracket. Still under the 5kg payload...

But I cannot counterbalance the setup with the weight supplied with the Star Adventurer! it is WAY too heavy on the camera side - it just doesn't balance at all... I've even tried removing the screw on the shaft to slide the weight as far down as it can go but still grip, and it's still way off being anywhere near balanced.

It is advertised as being able to balance a 5KG (or 11lb) payload with this weight and shaft setup... as I said I don't expect it to be perfect and I know you should never overload a mount but I thought being 1.5Kg under the threshold would at least give me a chance of being able to balance in sufficiently.

As I said I'm a complete novice so apologies for my naivety if it's a simple fix?! but when you counterbalance a setup you should be able to turn the mount 90 degrees and the equipment sits happily in the equilibrium... correct? but physics says this just isn't going to balance without adding more weight to the shaft, which will surely overload the mount?

Any advice on this would be great.

Thanks,

Nick

Share this post


Link to post
Share on other sites

The direct solution would appear to be some extra weight or a shaft extension. Probably the latter would be the better option.  :icon_biggrin:

Share this post


Link to post
Share on other sites
Quote

The direct solution would appear to be some extra weight or a shaft extension. Probably the latter would be the better option.  :icon_biggrin:

Thanks, are the threads across the Skywatcher range the same? I have looked into this but haven't found something I am confident is correct. If you have any recommendations that would be great (sorry I'm rubbish!)

Quote

I use my Lunt LS60 on mine with a door stop from Screwfix drilled out to slide over the rod.

Oh my! what a fantastic fix! Thank you! What's the weight of your scope setup? Do you have pretty consistent results?

 

Also, I was wondering, what is an acceptable amount to tighten up the clutch knob? as long as it still rotates, is that OK for the motor still?

Thanks so much :)

Share this post


Link to post
Share on other sites

Doubt if it's the same as other SW mounts, I drilled the doorstop out to 12mm

The solar setup weighs nearly 6Kg, tracks the Sun OK.

I tighten mine up pretty much as tight as I can with thumb and one finger.

Dave

Share this post


Link to post
Share on other sites
7 hours ago, Davey-T said:

Doubt if it's the same as other SW mounts, I drilled the doorstop out to 12mm

The solar setup weighs nearly 6Kg, tracks the Sun OK.

I tighten mine up pretty much as tight as I can with thumb and one finger.

Dave

Sorry for my naivety but are you saying that with the clutch knob fully tightened, I.e locked, the tracker will still rotate and track?

i thought this was locking it upright to obtain alignment then loosened for tracking so it will rotate? 

Am am I wrong here as well?!

Share this post


Link to post
Share on other sites

Yes, I look up the polar scope and rotate it so 6 o'clock is at the bottom and lock it to polar align then unlock it and rotate to aim at the target, relock and start imaging.

Dave

Share this post


Link to post
Share on other sites
4 hours ago, Davey-T said:

Yes, I look up the polar scope and rotate it so 6 o'clock is at the bottom and lock it to polar align then unlock it and rotate to aim at the target, relock and start imaging.

Dave

Thanks Dave. I think this is where my naivety shows. I thought the clutch knob was a lock for everything, and that it should be released to counter balance freely and track.

If I can lock this up, and not even all the way, I can achieve a good balance... (puts hands over face)

Thanks for all you help! 

Nick 

Share this post


Link to post
Share on other sites
On 25.8.2017 at 15:42, Astro Buer said:

Thanks Dave. I think this is where my naivety shows. I thought the clutch knob was a lock for everything, and that it should be released to counter balance freely and track.

If I can lock this up, and not even all the way, I can achieve a good balance... (puts hands over face)

Thanks for all you help! 

Nick 

You should still try to balance the mount with the clutch open. Try to do it with the counterweight shaft approximately horizontal - if it's well balanced, the shaft remains horizontal even with clutch open. For tracking the clutch should of course be locked, as Dave said.

In addition, note that you can adjust the balance somewhat also by sliding the dovetail bar of the declination axis-counterweight assembly in the clamp. By having as little overhang as possible on the camera side naturally helps with balancing a heavy setup. Of course, if you slide it too much you cannot see through the polar scope anymore, but if necessary you can manage by polar aligning without the dec/cw assembly and install that after PA (but be careful not to bump the mount out of PA when doing that).

If you can't achieve perfect balance without extra counterweight or shaft extension, I'm sure your mount will not break even if you track with slightly unbalanced 3.5 kg payload, but the tracking accuracy may suffer, as well stability (it will be more prone to vibration etc.).

And one more note of caution, since I saw that you are planning to use a 150-600 lens. 600 mm fl will likely be WAY beyond the tracking capabilites of Star Adventurer, even guided. 200 mm and less are fine even unguided, 300-400 mm with autoguiding. This is not to say SA is a bad tracker, I think it's quite amazing for what it costs and weighs, but it's still a really, really lightweight mount. And very nice also for visual solar/lunar/planetary mount with a small scope (like 4 inch Mak) :thumbright:

Share this post


Link to post
Share on other sites
On 27/08/2017 at 18:12, Axunator said:

You should still try to balance the mount with the clutch open. Try to do it with the counterweight shaft approximately horizontal - if it's well balanced, the shaft remains horizontal even with clutch open. For tracking the clutch should of course be locked, as Dave said.

In addition, note that you can adjust the balance somewhat also by sliding the dovetail bar of the declination axis-counterweight assembly in the clamp. By having as little overhang as possible on the camera side naturally helps with balancing a heavy setup. Of course, if you slide it too much you cannot see through the polar scope anymore, but if necessary you can manage by polar aligning without the dec/cw assembly and install that after PA (but be careful not to bump the mount out of PA when doing that).

If you can't achieve perfect balance without extra counterweight or shaft extension, I'm sure your mount will not break even if you track with slightly unbalanced 3.5 kg payload, but the tracking accuracy may suffer, as well stability (it will be more prone to vibration etc.).

And one more note of caution, since I saw that you are planning to use a 150-600 lens. 600 mm fl will likely be WAY beyond the tracking capabilites of Star Adventurer, even guided. 200 mm and less are fine even unguided, 300-400 mm with autoguiding. This is not to say SA is a bad tracker, I think it's quite amazing for what it costs and weighs, but it's still a really, really lightweight mount. And very nice also for visual solar/lunar/planetary mount with a small scope (like 4 inch Mak) :thumbright:

Thanks for this, Axunator. The problem is with the clutch open, I cannot get anywhere near counterbalanced. Even when sliding down the dovetail bar. I'm 'supposed' to be able the counterbalance 5kg but there is no way the SA with take my 3.5kg setup with the clutch open. Quite frustrating. 

Obviously with the clutch locked up it's solid as a rock when turning 180 degrees but that doesn't help my issue?

I'm fully aware of the limitations of this rig! I know I'll be lucky to get anything useable over 200mm but as I have the long lens, I was hopping have a go at least. 

Thanks for your help 😊 

Edited by Astro Buer

Share this post


Link to post
Share on other sites

If that's the case, and you want to use such a heavy setup on a long-term basis, it will be a good idea to get an extra CW. In itself, it's not unheard of that an EQ mount is supplied with less counterweights than what is required to balance maximum or near maximum advertised payload. In fact, it's quite usual, even with premium mounts costing xyz times more than SA...

I would be happy to try to balance SA with a supplied CW and 3-4 kg payload to confirm your observation (just to make sure there's no other potential issues with your gear that might explain this), but I recently sold mine after getting HEQ5 (forget about grab and go with that one!!).

Actually, one potential thing comes to mind: how tall is that Manfrotto ball head that you're using? It may shift the center of gravity of your camera gear too much away from the pivot point, thus aggravating the balance problem by increasing the leverage on the camera side (remember, to achieve a balance, the product of the mass and the distance of c-o-g of that mass from the pivot point should be equal on both sides). Since you have the 1/4-20" screw in the dec shaft, try attaching your lens/camera combo directly to that, omitting the ball head altogether, and see if it helps. You can still aim your lens anywhere you want by adjusting the RA and dec axes.

Even if balance could be achieved, I would use a ball head only with shorter and lighter lenses.

Good luck and clear skies!

  • Like 1

Share this post


Link to post
Share on other sites
On 30/08/2017 at 17:40, Axunator said:

If that's the case, and you want to use such a heavy setup on a long-term basis, it will be a good idea to get an extra CW. In itself, it's not unheard of that an EQ mount is supplied with less counterweights than what is required to balance maximum or near maximum advertised payload. In fact, it's quite usual, even with premium mounts costing xyz times more than SA...

I would be happy to try to balance SA with a supplied CW and 3-4 kg payload to confirm your observation (just to make sure there's no other potential issues with your gear that might explain this), but I recently sold mine after getting HEQ5 (forget about grab and go with that one!!).

Actually, one potential thing comes to mind: how tall is that Manfrotto ball head that you're using? It may shift the center of gravity of your camera gear too much away from the pivot point, thus aggravating the balance problem by increasing the leverage on the camera side (remember, to achieve a balance, the product of the mass and the distance of c-o-g of that mass from the pivot point should be equal on both sides). Since you have the 1/4-20" screw in the dec shaft, try attaching your lens/camera combo directly to that, omitting the ball head altogether, and see if it helps. You can still aim your lens anywhere you want by adjusting the RA and dec axes.

Even if balance could be achieved, I would use a ball head only with shorter and lighter lenses.

Good luck and clear skies!

Thanks so thanks so much for all your advice. I tried this last night (omitting the ball head) but still no luck. I am going to have to add some more weight to the shaft. 

It's worth a go but I think this camera lens combo may just be a little too much for the SA... it's a great little mount that will serve me well with shorter lenses.

Again, thank you all for your help. I really appreciate it! 

Share this post


Link to post
Share on other sites
On 24/08/2017 at 23:35, Davey-T said:

I use my Lunt LS60 on mine with a door stop from Screwfix drilled out to slide over the rod.

http://www.screwfix.com/p/dome-weight-door-stop-satin-stainless-steel/44030

Dave

SWSA-LS60-3.png.ebaa8edc5b03dcc64102f10ef063c70c.png

 

Hi,

Whats the weight of that door stop ? I'm looking for some extra count weight but don't need another 1kg one that comes with the Star Adventurer.

Thanks.

Share this post


Link to post
Share on other sites
38 minutes ago, SAW said:

Hi,

Whats the weight of that door stop ? I'm looking for some extra count weight but don't need another 1kg one that comes with the Star Adventurer.

Thanks.

Weighs more than a kilo about 1.2 kilo I think.

Dave

  • Thanks 1

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Recently Browsing   0 members

    No registered users viewing this page.

  • Similar Content

    • By Kronos831
      Hey guys!i need to make this quick! I want to get a new 6mm eyepiece.I have a 8" f6 dob and i want to get a nice 200 mag and put the telescope to its limits at 400x
      The most i ve seen with is 240x for Jupiter and Saturn .i ve heard they looked stunning at 400x and i am keen on trying it.Ive got my eyes on a 6mm Skywatcher UWA eyepiece.and i have a Bst Starguider 2z Barlow lens.And i seem to be having problems with my 8mm Bst Starguider (300x in total).the bst has a 16mm eye relief and a 21mm lens diameter,but when i barlowed it and look at the moon yesterday,it was hard finding the right spot to look through the eyepiece and when i moved the image disappeared.I dont know if it will have that effect on planets,when I looked at mars it was fine but i definitely want to avoid that from happening again.Will it happen?
      The Skywatcher eyepiece i want to buy has a 16mm eye relief too.I dont want to make the same mistake now , i want a 6mm eyepiece at the price range of 50-70 euro either from flo or amazonuk.If the Skywatcher will have similar results,can you suggest another one?
    • By Dinglem
      I've upgraded my focuser so have a Skywatcher Dual-Speed Low Profile 1.25/2" Crayford focuser for sale £70 delivered to UK only.
      Bank transfer or Paypal F&F preferred.
       
       

    • By Owmuchonomy
      Wrapping up in double layer goose feathers I braved the obsy last night.  I planned a tour of Auriga with a view to chucking in some favourites.  I set up the ED150 on the AZ EQ 6 and fitted the WO quartz diagonal accompanied by my ES 20mm 82'.  I stuffed my Astronomik 1.25" UHC (bargain price thanks @FLO) in my pocket too.  This set up required the retro children's playroom chair with the legs sawn down due to the position of Auriga. I spent about half an hour checking the plethora of open clusters sprinkled in or near the Milky Way.  The sky was one of the best this season so it was a jewelled spectacle and the ED150 reveals such sharp colours enabling me to distinguish the cooler stars in some of the clusters particularly the occasional red giant.  As Monoceros reached the meridian I moved to the open cluster associated with the Rosette. Now, for all my efforts over the years, the emission nebulosity has eluded my eyes but tonight with this newish 6" frac I was somewhat taken aback to see a doughnut appear in the view.  Switching to a view with the UHC filter was nothing short of astonishing!  It wasn't just there; I was falling into its centre.  Texture, depth and dark globules were easily discernible.  The extent was slightly larger than the FOV with the 20mm so I slewed slowly around and the perimeters and varying consistency of the Ha emission were easily picked out.  I spent a long and happy time soaking this up; it was truly outstanding.  Thoroughly recommended.  I retired happily to the warm kitchen and toast.
    • By Greg6498
      Hello all!
      I just installed this Lacerta 1:10 Micro Transmission focuser on my 8” Skywatcher Dobsonian. It is a direct replacement for the stock focuser and works extremely well. I was surprised at how easy it was to install! Ordered it from 365Astronomy and got fast shipping.
       


    • By Kronos831
      This is probably my options as of now:I will definetly buy a 12mm BST Starguider A 2X BST Barlow( So thats 100x and 200x magnification) 
      AND Either:
      15MM BST STARGUIDER VS 25MM STARGUIDER
      My dobsonian telescope will include:A 25mm and 10mm Eyepiece . So the obvious awnser is to go for the 15mm BUT i ve read in reviews that the bst s have are noticabely better than the eyepieces that come with my telescope.So i am wondering, should i buy the 25mm or the 15mm BST? 
       
      Also is it worth to barlow either 25mm eyepiece to make 12.5mm and ditch the 12mm i am definetly buying for a 6mm one? i am thinking not because if i barlow the 6 mm it will give me 400x and i think that is too much magnification for the image to appear clear , plus i will also barlow the 10 mm to give me a 240x the acceptable limit for good clarity / magnification ratio (i ve read that and not sure if its true or not). Thanks again for your time and help!
      This forum has been very polite, welcoming and kind to noobs like me just getting into the hobby XD I hope i can one day look back at myself and laugh at my ignorance! This site has been truly amazing and i hope i can stay a member for a long time to come!
      Thanks as always
      Clear skies everyone
      Kronos
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.