ICEINSPACE
Most Read Articles
Moon Phase
CURRENT MOON Waxing Crescent
38.6%
The Sun Now
Time Zones
Sydney*
5:38 pm
Perth
2:38 pm
Auckland*
7:38 pm
New York
1:38 am
Paris
7:38 am
GMT
6:38 am




Go Back   IceInSpace > Beginners Start Here > Beginners Equipment Discussions

Reply
 
Thread Tools Rate Thread
  #1  
Old 31-08-2018, 09:00 AM
Forge
Registered User

Forge is offline
 
Join Date: Sep 2017
Posts: 16
Do Alt-Az GoTo mounts require constant realignment?

I've got a Skywatcher 12" GoTo recently and after a month or so of use I've found a minor issue. Before each viewing session I collimate and align it and for a good hour, the GoTo function (i.e. selecting an object and the telescope slewing to it) is almost pinpoint accurate. However after that using the same function, I have to manually use the controller to adjust it by quite a few degrees to get the selected object into the center of the eyepiece.

Is that expected behavior due to the nature of alt-az mounts or does it indicate a problem with the motors or encoders in my specific mount?

Just read the manual and it seems I could use the PAE function to try and correct this, but I've not tried it yet.

Thanks
Reply With Quote
  #2  
Old 31-08-2018, 11:16 AM
gaseous (Patrick)
Registered User

gaseous is offline
 
Join Date: May 2016
Location: Brisbane
Posts: 404
I think you're doing well if you're getting an hour of pinpoint accuracy! I find they can tend to lose a little accuracy over time, and tend to realign after a few hours if the target object is not within a low-power field of view, but if it's out by several degrees, then something may be amiss.
Reply With Quote
  #3  
Old 31-08-2018, 11:56 AM
Hemi
Registered User

Hemi is offline
 
Join Date: Dec 2010
Location: Darwin
Posts: 165
The pointing accuracy of gotoís is reduced (Iíve read), with the SW encoders on. I presume that error compounds with time. You could try and see what happens with the encoders off.... I rarely manually locate if Iíve aligned so leave the encoders off mostly.

Cheers

Hemi
Reply With Quote
  #4  
Old 31-08-2018, 02:14 PM
Allan_L's Avatar
Allan_L (Allan)
Member > 10year club

Allan_L is offline
 
Join Date: Mar 2008
Location: Central Coast NSW
Posts: 3,000
something I posted in another thread:
Quote:
Originally Posted by Allan_L View Post
Maybe try to check the integrity of the encoders.

Centre an object.
Note the RA Dec from the hand controller.

(This is from the skywatcher manual
Utility > Show Position - This displays the coordinates of the location where the telescope is currently pointed. The coordinates can be displayed in Dec and RA, Alt and Azm, or Ax1 (the angular reading of the elevation) and Ax2 (the azimuth axes of the mount). Use the scroll keys to choose your desired reading
)

Rotate the mount through 360* then check that the RA Dec reading is the same.

You may also move it back and forth to try to induce any encoder slippage error and return to the original object to check the displayed RA Dec are the same.
The accuracy is always best in the quadrant where your alignment stars are.
I also found the accuracy decreased as the night got colder.
That other thread also had some hints on picking quality alignment stars, just in case you missed it.
Reply With Quote
  #5  
Old 31-08-2018, 06:21 PM
Forge
Registered User

Forge is offline
 
Join Date: Sep 2017
Posts: 16
Thank you all, seems like the scope is doing alright. But I will try your suggestions to do some further testing
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 04:38 PM.

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