191 replies to this topic

[Poynting]

Question to you all: does your Skyguider Pro have this kind of play in RA?

 

https://www.youtube....h?v=nYFY5kvbKX4

 

https://www.youtube....h?v=JQVBgY5N3GA

 

I followed the pdf and found that neither my worm gear nor gear box move while moving the RA block, it just seems like there is play between the ring gear of the RA block and the worm gear.

 

Normal?

[Hypoxic]

"silver anti seize grease" ??? 

 

What about Super Lube?  That's what I use.

I used the anti seize because it’s anhygroscopic, resists corrosion and salt, and in my experiences works really well as a lube on gears such as these; I’ve had really good results with it. I’m sure there are all sorts of lubricants that could be used, this was just my selection.

 

Super Lube! I’ll have to look into that one, I’m not familiar with it.

Edited by Hypoxic, 12 March 2019 - 12:31 AM.

[Hypoxic]

Question to you all: does your Skyguider Pro have this kind of play in RA?

 

https://www.youtube....h?v=nYFY5kvbKX4

 

https://www.youtube....h?v=JQVBgY5N3GA

 

I followed the pdf and found that neither my worm gear nor gear box move while moving the RA block, it just seems like there is play between the ring gear of the RA block and the worm gear.

 

Normal?

Mine does not have that play, it’s pretty solid. But then again I haven’t used it much either. Maybe it’s a usage thing?

[Hypoxic]

The wedge. 

Remove the locking arm (note the metal washer)

Attached Thumbnails

• 
• 

Edited by Hypoxic, 12 March 2019 - 01:44 PM.

[Hypoxic]

Use an allen wrench to losen the pivot bolt,

then push it out with your finger from the other side.

Grease and set aside.

Attached Thumbnails

• 
• 

[Hypoxic]

Remove the top portion taking note of the plastic washers.

oops.. I touched the grease...

inspect the plastic washers and clean up any excess flashing around the center hole. Mine had lips of extra plastic that needed trimming.

Attached Thumbnails

• 

Edited by Hypoxic, 12 March 2019 - 01:41 PM.

[Hypoxic]

Grease the worm and ring gears.

if you have a tiny allen wrench you can loosen the grub screw and remove the worm gear to grease the bushings. I’ll do that once I receive my set in the mail.

Attached Thumbnails

• 
• 

Edited by Hypoxic, 12 March 2019 - 01:36 PM.

[Hypoxic]

Grease the tips of the two azimuth bolts and reinstall.

Attached Thumbnails

• 

[Hypoxic]

Put it back together in reverse order. Piece of cake! 

Attached Thumbnails

• 

[Jim Waters]

I used the anti seize because it’s anhygroscopic, resists corrosion and salt, and in my experiences works really well as a lube on gears such as these; I’ve had really good results with it. I’m sure there are all sorts of lubricants that could be used, this was just my selection.

 

Super Lube! I’ll have to look into that one, I’m not familiar with it.

Have you ever tried Damping Fluid (Medium) for lubing the worm and drive gear?

 

http://www.clearcopr...ing_fluids.html

[Hypoxic]

Have you ever tried Damping Fluid (Medium) for lubing the worm and drive gear?

 

http://www.clearcopr...ing_fluids.html

I do use something of the sort on my automotive brake carriers; keeps things actuating nicely.

 

 

[DanielJStein]

Have you ever tried Damping Fluid (Medium) for lubing the worm and drive gear?

 

http://www.clearcopr...ing_fluids.html

This is what I am curious about!

[Hypoxic]

I was using my Skyguider Pro last night and was getting frustrated with the azimuth screws while polar aligning. They were very sloppy and it took several turns to get the wedge to rotate in either direction then it would catch and polaris would jump in the view finder. Super annoying because then I would have to spin the screws in the opposite direction several times before they caught again. Fine tuning was nonexistent.

 

So today I took it all apart and gave it a closer look. The post on the inside that the two screws push against was loose and about to fall off. So when I was turning the screws to adjust the polar alignment, the post was spinning and tilting to the left and right. I tightened up the screw on the bottom of the wedge and got my fine tuning back.

Attached Thumbnails

• 

[Hajfimannen]

Good job. I was also frustrated with my original wedge. So I bought the Skywatcher version. 

[PhilipPeake]

Took a look at my wedge today.

First observation was that it was pretty much bone dry. There was a hint of grease on the gear, but that was all.

 

The second observation was that the plastic packing/bearing surface washers were pretty screwed up.

Looks like during assembly it was hard to get the washers into place, so they became distorted on the edges, and the center hole didn't really line up, so the bolt was just forced through -- that was the "flashing" referred to above.

 

With them in that state it was hard to get them back in on re-assembly.

If anyone knows of a source for replacements, I would like to know - and if they are easily available, I would recommend obtaining a set before disassembly. 

 

Anyway, after applying a little PTFE grease, things are considerably smoother.

 

I should have measured the plastic washers while I had it apart, outside diameter, inside diameter and thickness. If anyone decides to do theirs, and has the tools to measure, please post the measurements here. I don’t know how easy it would be to find direct replacements, but think that bronze washers/shims might actually be a better replacement.

Edited by PhilipPeake, 14 April 2019 - 06:40 PM.

[Hypoxic]

You could cut a set out of a plastic milk jug. Use the old ones as templates.

 

OD - 32mm

ID - 10mm

thickness is about 0.5mm

 

Water bottle would work.

Edited by Hypoxic, 16 April 2019 - 12:23 PM.

[PhilipPeake]

You could cut a set out of a plastic milk jug. Use the old ones as templates.

 

OD - 32mm

ID - 10mm

thickness is about 0.5mm

 

Water bottle would work.

Interesting.

 

If yours is a fairly new one, it looks like they are using different shims - with a larger hole.

Mine were nowhere near 10mm ID, more like just a bit larger than the bolt.

 

Maybe they noticed the assembly problems and the misaligned plastic getting forced into the hole, making the entire thing stiff.

 

Personally, I would have spent a bit of effort on improving assembly practices and QA. But I suppose this is cheaper/easier.

 

Not that it really matters, so long as it works.

 

I keep wondering about the William Optics base, but a) its a bit expensive, and b) out of stock everywhere.

[Hypoxic]

I cut the flashing from around my center hole, probably the reason for the size difference. The shims are just there to snug things up, I don’t think the hole size really matters much as long as it’s close. I’m going to cut some cleaner ones here soon; try some different materials just to see if it changes anything, for fun.

 

If you have the money to throw at the WO base, go for it. To me, personally, it’s just a “Bling-Bling” part. My Skyguider Pro wedge works perfectly fine. After using my setup a few times now, I can see that the stability is all in the tripod. No use buying an expensive part if your foundation sucks to begin with.

 

For me, this was a good purchase, tripod is rock solid now! (pun intended)

https://www.amazon.c...0?ie=UTF8&psc=1

[PhilipPeake]

I cut the flashing from around my center hole, probably the reason for the size difference. The shims are just there to snug things up, I don’t think the hole size really matters much as long as it’s close. I’m going to cut some cleaner ones here soon; try some different materials just to see if it changes anything, for fun.

 

If you have the money to throw at the WO base, go for it. To me, personally, it’s just a “Bling-Bling” part. My Skyguider Pro wedge works perfectly fine. After using my setup a few times now, I can see that the stability is all in the tripod. No use buying an expensive part if your foundation sucks to begin with.

 

For me, this was a good purchase, tripod is rock solid now! (pun intended)

https://www.amazon.c...0?ie=UTF8&psc=1

I just like nicely engineered things :-)

Overall, the SGP seems well engineered. The wedge is more “functionally ok”.

 

I agree about the tripod (stable base) being most important, and I did spend more money to upgrade from my old tripod, which was perfectly ok for normal photography, but a but lacking for Astro work.

 

The primary reason for trying to make the wedge smoother in operation was seeing how hard the less than silky smooth adjustments made the fine adjustment using my PoleMaster. Wasn’t too bad with the polar scope, and I never tried for absolute perfection with the scope, but the PoleMaster encourages very precise alignment. At the fine level of adjustment needed, the out of box wedge was a little jerky.

 

My shims looked like they had been pushed too far down, with the bottom getting bent and the misaligned hole forced open, causing the “flashing”.

 

Anyway, it’s much better now. If I pull it apart again I will look for some variable thickness brass or bronze shims and see how they work. As you say, it’s really just packing to avoid wobble though...

[Hypoxic]

“I just like nicely engineered things :-)”

 

Join the club. 

[FrostByte]

I don’t like the amount of slop in the altitude adjustment knob. The set screw holds on the knob with a set screw in a flat groove in the shaft, but when the set screw loosens slightly, the knob slips back and forth as the set screw slides in the groove. 

 

I couldn’t find an appropriate sized spring to place at the end of the shaft, so I stacked up 4 o-rings inside the knob to apply pressure on the end of the shaft. Even when the set screw is loose, no more play in the knob! Small tweak, but it has a much better feel now. 

Attached Thumbnails

• 

[vidrazor]

So I noticed my polar scope was a little out of alignment with RA axis, i.e. when rotating RA something placed in the center initially wobbles around the center in an ellipse.

 

This occasionally happens and can be fixed as per the pdf attached above.

 

After doing this I redid another "mod" I have done to make my polar alignment (PA) even better, I hope.

 

Firstly, most people perform PA with this type of mount by aligning Polaris to a position on the reticle as given by a polar finder app. This type of PA has some inherent issues, namely parallax seen between Polaris and the reticle when moving your eye around in front of the scope, and also how "level" your reticle is.

 

The second issue of the reticle is that if your reticle is off by an angle from being truly at the "12 o'clock position" with respect to the horizon/sky, then when you place Polaris in the "right" position on the reticle it will actually be off by that angle that your reticle is rotated from the correct position.

 

The manual and many tutorials online state that since the Skyguider Pro has a hole to allow the red LED light to illuminate the reticle close to this "12 o'clock position" that you just have to turn RA until the light shines in and you are good to go for PA. I found that the window when turning that lets the LED illuminate the reticle is not infinitesimal, and there is a lot of room allowing the light to shine in when the reticle is far off from being level.

 

Here is my solution:

 

First always level the Skyguider Pro or tripod. The tripod being as level as possible provides a consistent reference for each time you adjust the RA to get the reticle in the right position. If the tripod is not level, then the reticle can be off by how much the tripod is tilted.

 

 

 

I use this level I bought on Aliexpress, but I'm sure any level can work.

 

After leveling the tripod, I then use a distant object that is known to be vertical, like vertical edges on a building, or a radio tower / mast.

 

I then adjust the RA such that the reticle's vertical line is aligned with the vertical edge I am referencing.

 

Here you can see when I move the altitude knob of the Skyguider the tower in the view stays along the vertical line of the reticle:

 

 

 

 

Now that I know the reticle is truly "level", in the "12 o'clock position", whatever you wanna call it, to the best of my ability, I mark two reference points as shown below with a silver sharpie:

 

 

One mark goes on the red stationary part of the Skyguider, and the other mark goes on the polar scope, so that they are aligned.

 

Now in the field, when I level my tripod, I just moved the markings together and I know my reticle is as good as it can get. Then I perform PA.

 

I hope that someone finds this useful.

Although I like this idea, I have a question concerning this. I have a level on my tripod, a Benro GC358F, and there is one on the iOptron alt-az mount. I noticed you put your Aliexpress level on the top of the tracker itself. I first leveled the tripod using it's own level. When I placed the alt-az mount on the tripod, the alt-az level was off. I then re-leveled to the alt-az level, which of course knocked the tripod level off. I then placed the tracker on the mount and put a Craftsman 939830 level on top as you have, and it was WAY off. I then removed the tracker and put the Craftsman on the top ridges of the alt-az dovetail mount and re-leveled again. All three levels differ from each other, and when I re-attached the tracker and placed the level on top of it, it was still way off.

 

So this begs the question; how do you know what is the proper level? In all honesty, I'm not sure I would trust the top of the tracker's plastic cover as being level. Although the levels are all off after leveling off the dovetail ridges, the tripod and alt-az levels are within the center circle, albeit opposite of each other.

What can you trust to be truly level?

Edited by vidrazor, 31 May 2019 - 08:48 AM.

[outlierrn]

I did some casual experiments using the built in level on my tripod vs the one on the SGP, and had much better result with the latter, FWIW.

[vidrazor]

I did some casual experiments using the built in level on my tripod vs the one on the SGP, and had much better result with the latter, FWIW.

Yes, I'm gonna go with that as well. Too many variables.

[vidrazor]

FYI, I ripped apart the iOptron alt-az mount, removed all the lubricant and cleaned all the surfaces and replaced the lubricant with high viscosity silicone damping fluid. It took a while to find a small enough quantity of it, but I found it's readily available at radio-controlled car hobby shops, as apparently it's used in the tiny shocks for damping. It only cost me $4.50. I found an 80,000 CST fluid, the densest viscosity the shop had, and it has significantly improved the performance of the alt-az mount. If you're considering rebuilding your iOptron alt-az mount, I highly recommend this. If you can find a higher viscosity silicone damping fluid, go for it, as I felt it could have used more viscosity, but this is still a significant improvement. Hope this helps.

 

After rebuilding the alt-az mount I took my new Skyguider out today to check the polar scope alignment on some flagpoles and distant point sources, and much to my relief the scope is good out of the factory, so now I can start performing some setup test and start doing some test shots to get everything into the groove.

Attached Thumbnails

•