Go Back   IceInSpace > Beginners Start Here > Beginners Equipment Discussions

Reply
 
Thread Tools Rate Thread
  #1  
Old 19-08-2012, 10:07 AM
LAW (Murphy)
Registered User

LAW is offline
 
Join Date: May 2012
Location: Brisbane
Posts: 204
EQ5 needs a service? (Lots of questions, sorry)

Hey everyone, I picked up a cheap second hand EQ5 and it's been great, I've been working through Suzy's lists as well as a few planets and such but I'm starting to notice some limitations.

I've noticed a lot of backlash in the gears as well as irregular movement in slow motion, it feels like the shaft might be bent? It gets intermittently easier and harder to turn on the RA axis. And towards the zenith the DEC slow motion control seems to disconnect itself? The handle just freespins but the clutch holds until I move to a lower RA.

Also the motor drives take a long time to change direction, if I overshoot a target or go the wrong way (this happens more than I'm willing to admit) I have to run the motors at full speed for a few seconds to take up the slack before it starts to move, and then the easy/hard temperament of the gears makes it track at varying speeds so things tend to slowly wobble in a 6mm EP.

I pulled the motor drives out to see if I could find where the slack was coming from but it's a sealed unit, I did notice that the 'rack' gears on the axis are very worn. It looks like the steel worm gear has chewed through the aluminium rack gears. Is it possible to replace these as there isn't much 'tread' left?

Overall I'm very happy with the mount for the price I paid, but as an aircraft engineer I get a little OCD when things aren't perfect. I'd really like to modify the motor drives for PHD guiding via the 'Shoestring Astronomy' ST4 thingo, but I don't think the mount is precise enough in it's current state to benefit from guiding.

[EDIT] While I think of it, can I use a canon 450D with liveview as a guide camera in PHD? I have a Philips SPC900NC webcam which has been modified with a 1.25" adapter but the picture is so dark it can't pick up any stars, it even struggles to see the moon. From all accounts this is supposed to be quite a good webcam, what am I doing wrong?
Reply With Quote
  #2  
Old 19-08-2012, 11:00 AM
2stroke's Avatar
2stroke (Jay)
The devil's advocate

2stroke is offline
 
Join Date: Jul 2011
Posts: 816
Quote:
Originally Posted by LAW View Post
Hey everyone, I picked up a cheap second hand EQ5 and it's been great, I've been working through Suzy's lists as well as a few planets and such but I'm starting to notice some limitations.

I've noticed a lot of backlash in the gears as well as irregular movement in slow motion, it feels like the shaft might be bent? It gets intermittently easier and harder to turn on the RA axis. And towards the zenith the DEC slow motion control seems to disconnect itself? The handle just freespins but the clutch holds until I move to a lower RA.

Also the motor drives take a long time to change direction, if I overshoot a target or go the wrong way (this happens more than I'm willing to admit) I have to run the motors at full speed for a few seconds to take up the slack before it starts to move, and then the easy/hard temperament of the gears makes it track at varying speeds so things tend to slowly wobble in a 6mm EP.

I pulled the motor drives out to see if I could find where the slack was coming from but it's a sealed unit, I did notice that the 'rack' gears on the axis are very worn. It looks like the steel worm gear has chewed through the aluminium rack gears. Is it possible to replace these as there isn't much 'tread' left?

Overall I'm very happy with the mount for the price I paid, but as an aircraft engineer I get a little OCD when things aren't perfect. I'd really like to modify the motor drives for PHD guiding via the 'Shoestring Astronomy' ST4 thingo, but I don't think the mount is precise enough in it's current state to benefit from guiding.

[EDIT] While I think of it, can I use a canon 450D with liveview as a guide camera in PHD? I have a Philips SPC900NC webcam which has been modified with a 1.25" adapter but the picture is so dark it can't pick up any stars, it even struggles to see the moon. From all accounts this is supposed to be quite a good webcam, what am I doing wrong?

Well it looks like you found the problem with your eq5 and that being the motor/gear units. You can buy new ones and replace http://www.bintel.com.au/Mounts---Tr...oductview.aspx or see if anyone has a spare here they could sell you in the WTB section. As for the gears and replacing them in the drive units i have no idea sorry Maybe google can help if no other users can.

No you can't use live-view to guide Your Toucam is not sensitive enough to guide with stock really. What you can do is a black and white mod by getting a sony ICX098BL chip and repace the color one you have atm, These cost about $30 plus shipping. The next option is the LX mod for long exposures so you can get .5/1sec exposures for guiding. I don't think you can guide at all with the 900nc without modding because a 1/4 of a sec just isnt enough with a colored sensor

http://www.framos.eu/de/home.html these guys will ship single units of the sensor there nearly the only ones i know that will, besides commercial stores that will rape you.
Reply With Quote
  #3  
Old 19-08-2012, 01:30 PM
Shiraz's Avatar
Shiraz (Ray)
Registered User

Shiraz is offline
 
Join Date: Apr 2010
Location: ardrossan south australia
Posts: 4,918
The rack gears are ground to fit the cylindrical shape of the worm and look pre-worn - could this account for your description of them being very worn? A big issue with these mounts seems to be free play in the worm/gear assemblies and as a first step, you might get a major improvement just by adjusting out the slack in both axes - if you haven't already done it. The worms should mate closely with the gears, leaving only just enough clearance to ensure that they do not bind. I recall seeing a video tutorial on how to do it - should be able to find it with Google. From memory, it involves loosening the two main holding bolts and adjusting the play with the central set screw - then re-tightening.

Last edited by Shiraz; 19-08-2012 at 06:30 PM.
Reply With Quote
  #4  
Old 19-08-2012, 06:52 PM
GeoffW1's Avatar
GeoffW1 (Geoff)
Registered User

GeoffW1 is offline
 
Join Date: Sep 2006
Location: Sydney
Posts: 1,847
Quote:
Originally Posted by Shiraz View Post
I recall seeing a video tutorial on how to do it - should be able to find it with Google. From memory, it involves loosening the two main holding bolts and adjusting the play with the central set screw - then re-tightening.
Hi,

Here are a few of them

http://www.astro-baby.com/heq5-rebuild/heq5-m1.htm

http://www.astro-baby.com/heq5-rebuild/heq5-we1.htm

http://www.iceinspace.com.au/63-432-0-0-1-0.html

http://www.astronomyboy.com/cg5/

http://www.beevo.com/rework.htm

Cheers
Reply With Quote
  #5  
Old 19-08-2012, 11:05 PM
2stroke's Avatar
2stroke (Jay)
The devil's advocate

2stroke is offline
 
Join Date: Jul 2011
Posts: 816
is this the video tut

Will see if i can find a place selling replacement spur gears and post back, Heq5 here so i have no idea on the eq5
Reply With Quote
  #6  
Old 19-08-2012, 11:20 PM
2stroke's Avatar
2stroke (Jay)
The devil's advocate

2stroke is offline
 
Join Date: Jul 2011
Posts: 816
For gear replacement so far i found
http://www.hpcgears.com/

Hypertune
http://astronomer.proboards.com/inde...ay&thread=3079
http://nightskyforums.com/viewtopic.php?f=17&t=259
Reply With Quote
  #7  
Old 20-08-2012, 05:50 AM
LAW (Murphy)
Registered User

LAW is offline
 
Join Date: May 2012
Location: Brisbane
Posts: 204
That's great info, thanks guys! Now I just need to win lotto so I can afford everything I want
Reply With Quote
  #8  
Old 28-08-2012, 01:21 AM
Waxing_Gibbous's Avatar
Waxing_Gibbous (Peter)
Grumpy Old Man-Child

Waxing_Gibbous is offline
 
Join Date: Jul 2009
Location: South Gippsland
Posts: 1,768
Strongly suggest you visit: www.astrobaby.com for info on these mounts.
Extremely lucid and detailed instructions on DIY EQ mods and fixes.
Reply With Quote
  #9  
Old 28-08-2012, 08:30 AM
silv's Avatar
silv (Annette)
Registered User

silv is offline
 
Join Date: Apr 2012
Location: Germany 54°N
Posts: 1,110
Peter, the link opens a "page not found" for me.
Reply With Quote
  #10  
Old 28-08-2012, 08:50 AM
Larryp's Avatar
Larryp (Laurie)
Registered User

Larryp is offline
 
Join Date: Apr 2012
Location: Sydney
Posts: 5,244
Silv, the link should be astro-baby.com
Reply With Quote
  #11  
Old 28-08-2012, 09:00 AM
jjjnettie's Avatar
jjjnettie (Jeanette)
Registered User

jjjnettie is offline
 
Join Date: Feb 2005
Location: Monto
Posts: 16,741
I use my Phillips spc900 to guide with all the time.
I used to use it through a short tube 80mm using a focal reducer, now I'm using it with a 50mm finder guider.
What settings are you using for the camera? I have the shutter wide open and the gain just a wee bit to the left to darken the background so the stars stand out more.
Reply With Quote
  #12  
Old 28-08-2012, 09:35 AM
LAW (Murphy)
Registered User

LAW is offline
 
Join Date: May 2012
Location: Brisbane
Posts: 204
I checked out astro-baby, that's a great write up.
I'll have another go with the webcam on different software and see how it goes.

You're right Ray, the worm drives weren't worn, just the way they're made, haha, oops.

I've got an EQ6 now anyway so I'll probably sell the '5, it's a good mount but my scope was pushing the weight limit.
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 09:53 AM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Advertisement
Bintel
Advertisement