Mount strip & re-grease pros & Cons

[themos]

I'm getting a reading of 7.5 arcminutes polar alignment error.

But I'm having problems producing the plot for you,

[themos]

The problem is that you don't have Lambda Ursa Minoris in the frame. That star is on the other side of the NCP from Polaris and if you manage to turn the camera so that both Polaris and Lambda are in the frame in both positions, I will be able to get a plot.

[spaceboy]

Thanks Themos. I'm not sure how I will be able to get the other star you need as Polaris only just comes in frame when near park position and I'm not sure orientating the camera will make much difference but I will give it another go once I get chance. Doesn't look like I had much success with the drift alignment then ?? The lowest western star I could see was 27' above the horizon and in the east would have been 34'. Are these to high ?? The drift star did not seem to move in the direction the instructions said it would so I wonder if that is where I went wrong ?? Drift Alignment of an Equatorial Mount I used the RA drive to move the drift star along the east/ west line to make sure the cross hairs were orientated correctly but some times the star would slowly move along the line rather than north or south direction. Should I have a go at the east/ west alignment first to reduce this drift ? The seeing is bad at the altitude I was using so the star did dance around a little so I struggled there a bit.

Thanks again.

[themos]

I don't use drift alignment because I think it takes too long to produce results worthy of the wait.

The way you can frame both stars is to change the declination, either slew in Dec or undo the clutches and reposition. I am not sure if you can use a focal length that's shorter than what you used. Your image scale came to about 4 arcsec/pixel and I prefer working with ~8 and above. The thing to remember about the 2 orientations is a) you need a good angle between the two (I choose about 90 degrees but 40 degress will do) and the second one must be so that when you look at how the camera is positioned, it's not tilted left-right but only up-down. Does that make sense? That way, we can interpret the image's x and y directions as azimuth and altitude directly.

[spaceboy]

Thanks again Themos. Fingers crosse it stays clear later and I'll take a few pics. Fingers crossed I get one pair right . Also what is the second star needed in the pic ?

[themos]

It is highlighted in this pic

[spaceboy]

[spaceboy]

Well give up on drift aligning. Staring endlessly at a star waiting for it to or not to move 22:00 to 01:40 this morning faffing around on trying to establish just AZ adjustments . Waste of a clear night in my book.

I admit defeat. What other options do I have open to me ? I take it you need to spend money ??? seems to be the trend with this hobby.

[malc-c]

Try this

Zeroing it in. Using a DSLR or CCD to align your scope

[themos]

The problem with that is that it takes at least 2 minutes to get confirmation after every adjustment. My method requires a 10 second exposure followed by a 10 second plate-solve.

[lukebl]

Well give up on drift aligning. Staring endlessly at a star waiting for it to or not to move....

Surely, as you're permanently pier mounted, drift alignment is just a one-off exercise and hardly a great hardship in the great scheme of things! In my view it's well worth it in the long run if it means you're properly aligned.

Mind you, I'm now perfectly aligned but still take rubbish images!

[malc-c]

Luke, my thoughts exactly...

Whilst it's a pain having to set up a scope before use (used to take me three-quarters of an hour to cart everything out and set up before I built the observatory), its also part of the learning curve, and should be viewed as such rather than a chore... It strikes me that a lot of people these days are just too impatient. OK my set up time is reduced to around 5 minutes (open up, power on the mount, then boot the PC, un-park and select the target) but I still like the build up at twilight and the anticipation of how the night might progress.

Even in he days before the observatory I went the same pain of setting up only for the clouds to roll in less than an hour later... but then on other occasions it's rolled past and resulted in some of the best observing session I've experienced

[spaceboy]

1st pic in near enough park position. 2nd, 3rd & 4th at an offset all in the same place but I was unsure which was the 2nd star you needed so took 3 different angles.

Hope I got it right this time as my alignment went to pot after attempting to get the 2nd pic. (get the scope in a certain position and the RA doesn't want to move)

[spaceboy]

Surely, as you're permanently pier mounted, drift alignment is just a one-off exercise and hardly a great hardship in the great scheme of things! In my view it's well worth it in the long run if it means you're properly aligned.

Mind you, I'm now perfectly aligned but still take rubbish images!

The problem I have is the obsy was built around a 200K on an EQ5 and was only intended for visual astronomy. IE: I couldn't swing a cat even if I could fit the cat in with me. I now have a 200P on an EQ6 which both mount and newt are double the size of what the obs was originally intended for. As a result the counter weights and scope get there fair share of bumps. I think there has been an improvement trying to drift align but I am still getting some trailing. I don't get that in a 10 second exposure it already shows a trail yet in 148 the trail is not that significantly larger.

[themos]

What do you mean "took 3 different angles"? You put the scope in 3 different RA positions I hope! The only way my method is going to work is if the only difference between image #1 and #2 is turning the scope in RA. You can't reposition the camera between the two shots! If you have to re-orient the camera to get both stars in, you have to go back and take fresh #1 and #2 images. I hope this is clear.

Assuming that park.jpg represents a view with the x-direction horizontal, this is where your scope axis is pointing (according to park.jpg and offset.jpg)

So you need to move your mount's axis about 40 arcminutes to the right. That's about 550 pixels so you can do it by putting your camera so it's horizontal (but facing upwards), take a picture of Polaris and then move the polar axis of the mount to the right until Polaris has moved 550 pixels.

[spaceboy]

Sorry Themos forgive my total stupidity. Please use the first 2images. The other 2 were the camera orientated not the mount

I think I will have to come back to this again in the future anyway as I have identified a problem. I re-greased the mount with white lithium last September and this appears to have been a total waste of time and effort. I have been noticing the rattle you get in high slew getting louder and louder and it now appears the WL has already separated. I had also noticed GOTO has not been as accurate but put it down to PA being out but it looks like time for another strip & re-grease before I commit any more time to trying to aligning the PA. To say I'm ****** would be an understatement I think this is also causing the drift on stars as I now think I am having a similar problem to Steppenwolf http://stargazerslounge.com/diy-astronomer/54910-eq6-stripdown-re-grease-image-creep.html

The drift star did not seem to move in the direction the instructions said it would so I wonder if that is where I went wrong ?? Drift Alignment of an Equatorial Mount I used the RA drive to move the drift star along the east/ west line to make sure the cross hairs were orientated correctly but some times the star would slowly move along the line rather than north or south direction. Should I have a go at the east/ west alignment first to reduce this drift ?

Thanks again for everyone's help and I am sorry for wasting everyone's time but I don't see the point in me continuing until I can get a more suitable grease on the gears. Any suggestions on the grease. I see super lube (assume loctite) and I like the look of

this Finish Line Teflon Grease - From £6.95 - Worldwide Cycling Mail Order Specialists and Consultants - Parker International

If it is no trouble I would still be interested to see how close I got PA Themos that is if the 1st two images work ???

Sorry again for wasting your time guys Will have to re-grease my CG5 now aswell I don't know why all strip down guides I saw on the net recommend the same grease ?

[themos]

The picture in my last post used the first two images, park.jpg and offset.jpg. If they were taken as I asked, then your error is 40 arcminutes which is a lot. You should get it under 5.

[spaceboy]

The picture in my last post used the first two images, park.jpg and offset.jpg. If they were taken as I asked, then your error is 40 arcminutes which is a lot. You should get it under 5.

I'm not very good at drift aligning then In my defence it dose say east/west needs to be as close to the horizon as possible and conifers sit 8 ft to the west and a house 10 ft away in the east. the lowest I could manage was around 27-37' and these were not exactly east/west. Well at least it softens the blow of having to re-grease the mount I guess. Would have been gutted if I'd finally nailed PA.

[terrym2002uk]

I personally wouldn't recommend the finish line teflon. I've used this and I found it breaks down quite quickly probably due to it being biodegradable!

I would be inclined to use some specialist grease next time for the worm gears and drive wheels.

Have a look here: Newgate - Small volume distributor of speciality chemicals & lubricants

Maybe try a light fluorocarbon damping grease, at least something that is high impact with a good temp range for the worms/gears and something very light for the bearings and shafts.

Also, I find its good practice to slew your scope through an ra/dec sweep before starting out in the evening just to loosen things up and check there is no binding going on.

I've never understood the lets make it all super slippery approach to greasing the worms and gears, given the amount of torque stepper motors generate. Even a medium to heavy damp grease isn't going to stop the worm moving. Binding and general dirt is a bigger factor in poor movement.

Anyway that's by tuppence.

[spaceboy]

I personally wouldn't recommend the finish line teflon. I've used this and I found it breaks down quite quickly probably due to it being biodegradable!

.

This is the problem. Everyone on the net who have taken the time to do a guide all use white lithium grease. So it was for this reason I took it on face value that it was tried and tested. If I am honest I had my doubts when I found it didn't adhere well to gears when making adjustments. The Finish line grease seems to do all I would ask of it yet you say this too would separate prematurely. I am wondering if I would be just better off using universal grease. Works pretty good on cars and they are under all sorts of demanding situations and environments.

[spaceboy]

This is interesting. It points out that worm gears run at high temperatures due to there inefficient design Gears- Gear Lubrication / http://www.machinerylubrication.com/Read/169/worm-gear-lubrication

[spaceboy]

I've kind of messed up this thread Any way this is the winner me thinks LUCAS OIL RED 'N' TACKY WATER RESISTANT MARINE GREASE | eBay seems to be well respected on model forums for nitro vehicles and it's cheap.