Skywatcher EQ% GOTO

ozships · #1 16-07-2007, 07:51 PM

Hi,
I'm fairly new to astronomy (if you ignore 40 years of reading...) and am having problems with my new EQ5 GOTO mount. Following the instructions, I point it to the south pole and then try to use the three star align. The mount seems to go to odd places. I "Park" it, which points it back to the pole and then get it to point to Jupiter. When I do this, it points rougly to the ecliptic, but the RA appears to be mirrored (ie the right distance from the zenith, but on the wrong side). However, it seems to track objects when I manually point it manually. For example it tracked eta Carina quite happily for over five minutes before I moved to another object (manually).

Anyone got any ideas?

ozships · #2 16-07-2007, 09:33 PM

A bit more experimenting and it looks like the positioning is out by 4 hours RA and 5 degrees dec.

The declination I think is related to the alignment (I can't set the angle below 40 degrees at the moment, need to look at the mount a bit more to work out why).

Peter

iceman (Mike) · #3 17-07-2007, 07:48 AM

Hi Peter, welcome to IceInSpace!

I would certainly think that not being able to set the Altitude of the mount correctly would account for some, if not all of the errors in the Goto.

What is stopping you from lowering the angle? Have you loosened off both bolts enough?

DeanoNZL (Adrian) · #4 17-07-2007, 07:17 PM

Peter, Might pay to check the site location settings as well.
Re-enter the coordinates for the handset.
Hope this helps

KG8 · #5 17-07-2007, 07:28 PM

I had a similar effect once on my eq6, turned out to be I had altered the local time zone to -10 from 10! I had changed it unknowingly by accident, easy enough to do.

ozships · #6 17-07-2007, 07:28 PM

Hi,
I've checked both Lat/long, I've tried setting long in both east and west. I've tried two different sites around 30 km apart, so thgere is enough difference between the two to be relevant. Even tried both north and south, just in case I've entered some sort of time warp!

Quote:

Originally Posted by DeanoNZL

Peter, Might pay to check the site location settings as well.
Re-enter the coordinates for the handset.
Hope this helps

ozships · #7 17-07-2007, 07:32 PM

I'd thought of that. Visited Skywatcher web site and they have two timezone maps that conflict, so I have tried both + and - 10 hours.

Actually managed to get the scope pointing down at the ground at one stage! But this was due to the scope not being balanced properly and the drive slipping. Won't let that happen again!

Regards
Peter

Quote:

Originally Posted by KG8

I had a similar effect once on my eq6, turned out to be I had altered the local time zone to -10 from 10! I had changed it unknowingly by accident, easy enough to do.

ozships · #8 17-07-2007, 07:41 PM

I'm not sure here what the issue is. I've certainly loosened off both bolts and then adjusted it down to 40 degrees. It won't let me lower to 33. Tonight I'm going to take them out completely just to prove I'm not mad (well no more than my spouse accuses me of!).

I have noticed that the mount has a polar alignment scope, but there is a bar with a hole for the scope to view through is 90 degrees out of alignment, blocking the view. I've started to wonder whether there is something mis-aligned and blocking something inside.

However, I'm pretty positive that this isn't causing the RA issue.

Quote:

Originally Posted by iceman

Hi Peter, welcome to IceInSpace!

I would certainly think that not being able to set the Altitude of the mount correctly would account for some, if not all of the errors in the Goto.

What is stopping you from lowering the angle? Have you loosened off both bolts enough?

ozships · #9 17-07-2007, 08:24 PM

Iceman,
found out what the declination problem is. The second screw is mounted on a bar. This bar blocks the mount from lowering below 40 degrees. The only solution appears to be to remove the bar. But this means the mount is not locked and can tip over to 0 degrees.

Will have to check with the supplier!

Regards
Peter

Quote:

Originally Posted by iceman

Hi Peter, welcome to IceInSpace!

I would certainly think that not being able to set the Altitude of the mount correctly would account for some, if not all of the errors in the Goto.

What is stopping you from lowering the angle? Have you loosened off both bolts enough?

DaveO (David) · #10 17-07-2007, 08:41 PM

Quote:

Originally Posted by ozships

I have noticed that the mount has a polar alignment scope, but there is a bar with a hole for the scope to view through is 90 degrees out of alignment, blocking the view. I've started to wonder whether there is something mis-aligned and blocking something inside.

Peter

Can't speak for your other problems, but the polar scope I can help with - I had the same problem with my EQ6 and thought I was going mad!

The head of the mount (where the dovetail bar goes) can be loosened and rotated so that the hole in the axis (which the polar scope looks through) can be lined up. Can't remember which set of screws/nuts to loosen, but it is easy when you look at the gear to see which is right.

Now if only the LED for the illuminated reticle wasn't so bright, allowing you to actually use it!

Hope that helps.

ballaratdragons (Ken) · #11 17-07-2007, 08:48 PM

To see thru the polarscope you have to turn the scope/Dec around to 50 degrees.

ozships · #12 17-07-2007, 09:17 PM

Errrr... yep... silly mistake! Mind you, I took the polar scope out and had a look through it. Pretty cool, even if its not much use in Sydney!

Quote:

Originally Posted by ballaratdragons

To see thru the polarscope you have to turn the scope/Dec around to 50 degrees.

KG8 · #13 17-07-2007, 11:50 PM

If all else fails, read the manual. I would seriously recommend that in the case of the EQ mounts. One trick not in the book is the repositioning of the azimuth adjuster peg that juts up from the top of the tripod. It can be in either of 2 positions ( screw holes that is, you will see the other one vacant on top of the tripod ) In one position the extended counterweight bar sits "between" two tripod legs and the mount is not very stable in this configuration. Putting the peg in the other hole centers the CW bar over a single tripod leg that faces forward. This is much more stable and will prevent your mount tipping over when you take the OTA off it. In my case the peg came in the unstable configuration and I swapped it to the other hole.

A good mod is a thin plastic shim between mount and tripod. It helps when adjusting the azimuth bolts as it allows you to have the mount tightened down while you adjust it for polar alignment. You can make one out of any thin plastic. Some guys just cut up a 3L milk bottle. Just cut it donut shape with a width equal to the diameter of the tripod top and enough clearance in the hole for the mount to pass through. Don't forget a hole for the peg too!

PS. Don't forget to realign that polar scope else it will be useless to you.

These are great mounts but they need a few tweaks, like a resistor in-line to the polar alignment led.

ballaratdragons (Ken) · #14 17-07-2007, 11:54 PM

Another quirk with the Skywatcher GoTo mounts is that they don't find planets. When you dialled in Jupiter and it went elsewhere, that's why. It's a Skywatcher thing.

When I want to look at Planets, or image the sun, I enter an object right next to the Planet/Sun (an NGC etc) and then slew that little bit extra to get to the Planet/Sun.

KG8 · #15 18-07-2007, 08:35 AM

A lot of people rely on the 3-star alignment system to get it right but if you really want to improve accuracy you should spend some time getting the polar scope aligned with the mount, then align your ota with the polar scope and then get a really good polar alignment on octans. I'm 7km from the briso CBD and when I bother to set it up I can get the bright 3 of the octans stars in the scope. Sometimes my focus on the polar scope is out and I have to twist the end to get the stars just right for the city.

ozships · #16 18-07-2007, 06:50 PM

Read the manual!!!??? I'm an IT guy, we can't read!

The peg on the EQ5 mount is part of the mount casting, so it can't be moved (but thanks for the pointer, when I get a bigger scope, I'll have to upgrade my mount and will remember this. Hmmmm I've had an 8" scope for 5 months and I'm already looking at a bigger light bucket).

The plastic shim is a very good idea, I'll set up this weekend. Will have to experiment with the polar scope, but probably won't try to lign up on the big dipper....

Quote:

Originally Posted by KG8

If all else fails, read the manual. I would seriously recommend that in the case of the EQ mounts. One trick not in the book is the repositioning of the azimuth adjuster peg that juts up from the top of the tripod. It can be in either of 2 positions ( screw holes that is, you will see the other one vacant on top of the tripod ) In one position the extended counterweight bar sits "between" two tripod legs and the mount is not very stable in this configuration. Putting the peg in the other hole centers the CW bar over a single tripod leg that faces forward. This is much more stable and will prevent your mount tipping over when you take the OTA off it. In my case the peg came in the unstable configuration and I swapped it to the other hole.

A good mod is a thin plastic shim between mount and tripod. It helps when adjusting the azimuth bolts as it allows you to have the mount tightened down while you adjust it for polar alignment. You can make one out of any thin plastic. Some guys just cut up a 3L milk bottle. Just cut it donut shape with a width equal to the diameter of the tripod top and enough clearance in the hole for the mount to pass through. Don't forget a hole for the peg too!

PS. Don't forget to realign that polar scope else it will be useless to you.

These are great mounts but they need a few tweaks, like a resistor in-line to the polar alignment led.

Doug · #17 18-07-2007, 07:30 PM

Re Plastic shim, I used a circular protrator. I cut the center bar away and cut a bit out from the inner wall to alow for the peg.

Doug · #18 18-07-2007, 07:44 PM

What are you doing wrong Ken? You're pier mounted aren't you?
Those images I recently posted on/in 'the Als reticule' thread are 100% honest. From power up without any alignment at all, Jupiter is quite close, might even fall on a webcam chip; certainly close enough for any chip larger. I confident after a star alignment (with grease freed up) Jup would go pretty darn close to center.
I've never tried the Sun though; figured for safety reasons it would be placed in a no go zone.

cheers,
Doug

Quote:

Originally Posted by ballaratdragons

Another quirk with the Skywatcher GoTo mounts is that they don't find planets. When you dialled in Jupiter and it went elsewhere, that's why. It's a Skywatcher thing.

When I want to look at Planets, or image the sun, I enter an object right next to the Planet/Sun (an NGC etc) and then slew that little bit extra to get to the Planet/Sun.

Doug · #19 18-07-2007, 07:51 PM

G'day Peter,
When I purchased my EQ6, (same controller as EQ5) it went belly up on me. when Sirius was 30 or so degrees above the Eastern horizon it insisted on pointing the scope about 30 degrees below the Western Horizon.
I took it over to Tasco and after some tests by the resident guru there, I came away with a brand new controller and no problems since.
Keep it in mind; your controller can go belly up, but in general seem to work
cheers,
Doug

ozships · #20 19-07-2007, 07:17 PM

Thanks,
I'll keep this in mind. Thinking about it, I should be able to polar align and then tell it to go to aCrux. It should be obvious it it is wiring or not, assuming I've set the lat/long and time paramaters correctly. From there I'll try start hopping to different stars to see how it goes.

Quote:

Originally Posted by Doug

G'day Peter,
When I purchased my EQ6, (same controller as EQ5) it went belly up on me. when Sirius was 30 or so degrees above the Eastern horizon it insisted on pointing the scope about 30 degrees below the Western Horizon.
I took it over to Tasco and after some tests by the resident guru there, I came away with a brand new controller and no problems since.
Keep it in mind; your controller can go belly up, but in general seem to work
cheers,
Doug