ICEINSPACE
Most Read Articles
Moon Phase
CURRENT MOON Waning Gibbous
76.1%
The Sun Now
Time Zones
Sydney*
9:06 am
Perth
6:06 am
Auckland*
11:06 am
New York
5:06 pm
Paris
11:06 pm
GMT
10:06 pm




  #1  
Old 16-04-2017, 07:58 AM
SuperG
Registered User

SuperG is offline
 
Join Date: Oct 2014
Location: Meadowbank, NSW
Posts: 84
Balance of newtonians

My camera causes balance issues when the eq mount is in certain positions with a newtonian telescope (i.e. Hanging to the left). Is there a solution to this?
Reply With Quote
  #2  
Old 16-04-2017, 08:17 AM
Camelopardalis's Avatar
Camelopardalis (Dunk)
Drifting from the pole

Camelopardalis is offline
 
Join Date: Feb 2013
Location: Brisbane
Posts: 4,411
Stick something to the other side, roughly the same weight, as a counterbalance.
Reply With Quote
  #3  
Old 16-04-2017, 08:25 AM
markas (Mark)
Registered User

markas is offline
 
Join Date: May 2012
Location: Melbourne Australia
Posts: 253
Set up the system with the OTA facing to the SCP, and the RA counterweight bar pointing directly down.

Looking from directly in front on the mount, a line from the centre of the OTA camera port to the centre of gravity of the camera/focuser unit needs to be exactly parallel with the RA counterweight bar - ie the RA axis.

This gives lateral symmetry about the DE axis. If you have the DE axis balanced longitudinally and the RA axis balanced, then the system should be balanced in all positions.

If you want to rotate the camera for framing (or any other reason) you need a lateral counterweight to bring the lateral balance to the centreline of the mount axes.

Hope this helps. With direct drive mounts getting 'perfect' balance in all positions is critical; with standard mounts it is less so.

Mark
Reply With Quote
  #4  
Old 16-04-2017, 08:54 AM
glend (Glen)
Registered User

glend is offline
 
Join Date: Jun 2013
Location: Lake Macquarie, NSW
Posts: 4,956
Many mounts actually track better out of balance, as it can be used to keep gear systems meshed. Even in belt drive systems, if the ring and worm gear are still used a bit of unbalance can keep lash down.
On my 10" imaging newt i don't worry too much about the camera and filter wheel and coma corrector hanging off the focuser, i just balance the tube on DEC to be slightly rear heavy ( which works best on my mount), and east heavy ( which is focuser side anyway) on RA but not much. This seems to work in my situation. On my Mak-newt i have tube rotated in its rings to put the camera as near to the top as i can without blocking the guide scope. Its always best to stay under the rated imaging capacity of your mount, where weight and its placement is less an issue.
Reply With Quote
  #5  
Old 16-04-2017, 12:31 PM
leon's Avatar
leon
Registered User

leon is offline
 
Join Date: Apr 2006
Location: ballarat
Posts: 10,587
Agreed, it is better to have slightly more weight toward the gears a whisker out, than the other way where it wont hold tracking.
I found this out when using my G11 some time ago, but that is only my humble opinion

Leon
Reply With Quote
  #6  
Old 16-04-2017, 06:29 PM
SuperG
Registered User

SuperG is offline
 
Join Date: Oct 2014
Location: Meadowbank, NSW
Posts: 84
Thanks for the great replies. I will definitely try tout the focuser parallel with the counter weights. I have an eq5pro which I think has a max Weight between 9-10kg. My scope+guide scope is 7kg and my camera is ~800g. This is a little to heavy I think,especially since the mount came with two 5kg counterweights.
Reply With Quote
  #7  
Old 18-04-2017, 07:10 AM
sil's Avatar
sil (Steve)
Not even a speck of dust

sil is offline
 
Join Date: Jun 2012
Location: Canberra
Posts: 1,175
Dont ever expect good performance when close to the weight limit of a mount, 50% of the stated limit is about where you should be. You'll be forever having tracking issues and straining the mount. I always got best performance with setting the scope up with all the gear (making sure cables are not free to dangle/tangle which slightly chanegs weight balance. Manuaaly slew to the position I want to image and balance it there as perfect as possible. THEN do my star alignment etc. by the time the mount is up and tracking my target its rock steady in that position. Being close enough is just not good enough.
Reply With Quote
  #8  
Old 19-04-2017, 07:51 PM
NorthernLight's Avatar
NorthernLight (Max)
Settled

NorthernLight is offline
 
Join Date: Sep 2008
Location: Auckland, NZ
Posts: 309
I used to have the same problem on my Newton with my DSLR incl. a battery grip and a Powermate inbetween the camera and the focuser.
I solved it by turning the telescope tube around so that the camera is pointing down. Moving the camera and associated bits down and close to the mount improved everything balance related dramatically. I go 12.5min exposures with subarcsecond guiding and round stars without hearing the mount working. Hope this helps.
Attached Thumbnails
Click for full-size image (IMG_2545.jpg)
166.9 KB31 views
Reply With Quote
  #9  
Old 19-04-2017, 09:32 PM
SuperG
Registered User

SuperG is offline
 
Join Date: Oct 2014
Location: Meadowbank, NSW
Posts: 84
Northern Light, I really appreciate this response. I think this will work wonders.
Reply With Quote
Reply

Bookmarks

Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +10. The time is now 08:06 AM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Advertisement
FLI Cameras and Imaging Accessories
Advertisement
Bintel
Advertisement
OzScopes Authorised Dealer
Advertisement
Interest Free Finance
Advertisement
Lunatico Astronomical
Advertisement
NexDome Observatories
Advertisement
SkyWatcher WiFi Adaptor
Advertisement
SkyWatcher 2018 Catalogue
Advertisement
Astronomy and Electronics Centre
Advertisement