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  #21  
Old 01-07-2013, 11:19 PM
alexV
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Ill let you know as soon as weather will permit
Thank you
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  #22  
Old 10-07-2013, 09:33 PM
alexV
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went to MPAS observing site.
here are steps i took before drift alignment.

1. Tripod N pointed to true South.
2. Level the tripod.
3. Level the mount with telescope and view finder on
4. Synscan On
5.Skipped through setup (day, daylight saving, time etc)
6. Went in to Setup mode of Synscan an set tracking to Sidereal rate
7. Still in Setup mode of Synscan AutoGuide set to 1X
Synscan only allows to set to speed 1X, 0.5x, 0.75x,
0.25X and 0.125X for sidereal

I did drift alignment with reticle eyepiece and is very difficult to say if star goes up and down.
Next i took my orion autoguider connected it straight to my scope and computer. I used PHD with bulls eye.

I still get the same problem. Takes about 5 min to slowly go up and then down.



Any help would be great.
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  #23  
Old 10-07-2013, 09:55 PM
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Steffen
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Please note that I'm not really sure what your setup looks like (being a visual guy I'm spared the joys of auto guiding), but to me it sounds very much like you're guiding the drift away while trying to measure it. Hence the sine curve.

Wouldn't the auto guider, umm, auto guide as soon as it's plugged into the mount's auto guider port? Can't you see the drift in PHD without connecting the auto guider to the mount?

Cheers
Steffen.
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  #24  
Old 10-07-2013, 10:01 PM
alexV
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its not connected to auto guider port only to laptop through USB
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  #25  
Old 10-07-2013, 10:09 PM
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This is unlikely, but you'd see this if you had turned off tracking in RA rather than DEC Alex - effectively the sine wave reflecting your periodic error. Only other thought I have for now. What sort of mount is it? EQ6 worm period is about 8mins.
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  #26  
Old 10-07-2013, 10:14 PM
alexV
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eq5
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  #27  
Old 10-07-2013, 10:54 PM
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Not really sure about your issue but I would recommend drift aligning with PHD. I use the guide at the bottom of this page: http://www.njstargazer.org/PolarAlignment.asp

I have an EQ5 and the dy graph line can be a bit choppy if everything isn't balanced just right.

However if you're just learning to drift align it might be a better idea to get a cheap illuminated reticule eyepiece and do it 'the old fashioned way' for a while as it can be pretty tricky and you don't want to be dealing with camera and software as well as any quirks with the mount.
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  #28  
Old 11-07-2013, 01:02 AM
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Alex, the funny looking S shaped squiggle looks to me like a combination of (1) drift due to polar misalignment, and (2) periodic error of the mount and/or backlash.

First of all, have you calibrated the BYE reticle with the RA/DEC axes of your mount? The fact that they're perfectly vertical/horizontal on screen suggests to me that you haven't (though I could be wrong). Basically, what you need to do is:

1. use the arrows on your hand controller to centre the star on screen
2. use the RA buttons, e.g. East, to move the star to the edge of the screen
3. rotate the reticle in BYE so that the star is inside one of the reticle line pairs - remember that this is the RA axis
4. move the star back to centre using the opposite RA button, e.g. West

Now you're ready to drift align. You'll notice the star wobble back and forth along the RA axis due to periodic error - you can ignore this. You only need to pay attention to star drift away from the RA axis (i.e. towards north or south).


Btw - if you have computer control of your mount, it's worth looking into software-assisted polar alignment methods such as AlignMaster or PoleAlignMax. It's much faster and can handle *huge* initial misalignments. The latest Synscan firmware also has this feature built in.
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  #29  
Old 11-07-2013, 05:05 AM
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I don't see any units anywhere. How can you tell that it's "huge" ? Nor do I see any indication of RA and Dec axis. If we knew the period and the amplitude in arcsec then we could offer more meaningful suggestions.
That could well be a normal plot showing the periodic error of the worm.
You say that it's not connected to the ST4 guideport. Just to check - Is the mount connected to the laptop and running EQMOD or anything or is the only connection from the laptop to the guidecamera ?
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  #30  
Old 11-07-2013, 07:21 AM
alexV
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It's not connected to ST4 port and no eqmod
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  #31  
Old 11-07-2013, 07:34 PM
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Looking at your screen capture, is that the elapsed time (565 seconds) on the right side ? If so, you have a single sine cycle with a period of about 10 minutes. The EQ5 has 144:1 worm, giving a period of 10 minutes.
I would say that the star is drifting in Dec towards about 4 o'clock. You also have periodic error from the worm that makes the mount speed up and slow down in a direction that is right angles to the Dec, giving you the sine shape.

This is quite normal for mount that is tracking but not being guided. That is what guiding and/or PEC fixes.
I get a similar track for a Super Polaris mount with the height of the sine wave being about +/- 15 arcsec.

Depending on the numbers, you could be very well polar aligned or you could have horrendous periodic error.

My preference for drift alignment is EQAlign which I use with a webcam but it should work with your guide camera. I like it because I can use it with a non-goto mount but it's also very good at helping you through the process.
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  #32  
Old 12-07-2013, 09:30 PM
alexV
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Iam a bit confused with what should I do
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  #33  
Old 12-07-2013, 09:50 PM
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I'm a great believer in having 2 or 3 polar alignment techniques up your sleeve Alex. Would suggest:

1. Figure out how to drift align in software with tracking RA but none in DEC (Phd would allow this I believe - I use Maxim normally)
2. Have a go with the demo of alignmaster as others have suggested.

Personally I found drift aligning with a reticle far harder than a webcam - you have to wait quite a while to get a definitive signal. What Dave says is important too. You either have to rotate you cam to get its axis aligned with your RA/Dec axes OR do an alignment in software (like PhD) before drifting so the software already "knows" which directors are RA and Dec.

If its all getting too hard next best plan might be to find a kindred IIS spirit near your location.....
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  #34  
Old 13-07-2013, 11:43 AM
alexV
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ok thank you all for your help.
So from what i understood is that i need to learn fine tuning, is that right?
i also updated my SynScan it has a polar alignment now.

next time ill go ill do rough polar as usual, then ill try SynScan polar alignment i also got full copy of align-master.
I just glad to hear it is not mechanical issue.

Alex
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  #35  
Old 16-07-2013, 10:09 PM
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Quote:
Originally Posted by alexV View Post
ok thank you all for your help.
So from what i understood is that i need to learn fine tuning, is that right?
i also updated my SynScan it has a polar alignment now.
It would probably be easiest to pick a method (e.g. drift aligning with BYE, or using AlignMaster) and have a go - we can help you with any troubles you might have

As for the drift aligning with BYE... you need to centre the star and rotate the reticle like I described earlier - otherwise it won't work at all!

By the way, it is really really helpful to ensure that your mount is both (1) horizontally level, and (2) set up on firm ground that won't sink. Don't trust the bubble level on the mount (99.9% of them are incorrect from the factory) - you can use a bubble level or even a smart phone with a built-in inclinometer on top of the tripod plate. I find that setting up on grass or dirt causes no end of grief (one leg will inevitably gradually sink in), so I have a few Besser bricks half-buried into the dirt to keep things solid.
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  #36  
Old 17-07-2013, 08:30 AM
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pmrid (Peter)
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Quote:
Originally Posted by RobF View Post
I'm a great believer in having 2 or 3 polar alignment techniques up your sleeve Alex. Would suggest:

1. Figure out how to drift align in software with tracking RA but none in DEC (Phd would allow this I believe - I use Maxim normally)
2. Have a go with the demo of alignmaster as others have suggested.

Personally I found drift aligning with a reticle far harder than a webcam - you have to wait quite a while to get a definitive signal. What Dave says is important too. You either have to rotate you cam to get its axis aligned with your RA/Dec axes OR do an alignment in software (like PhD) before drifting so the software already "knows" which directors are RA and Dec.

If its all getting too hard next best plan might be to find a kindred IIS spirit near your location.....
Alex, since Rob has mentioned PHD, I might just throw in this - to drift align with PHD, you have to remember that after you have calibrated it, you then go to the Brain and Disable Guide Output before restarting the guiding. I mention it because it is often the obvious thing that I overlook.

Peter
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  #37  
Old 17-07-2013, 11:23 PM
alexV
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Thank you Peter
Ill keep that in mind

Alex
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  #38  
Old 17-07-2013, 11:26 PM
alexV
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Quote:
Originally Posted by naskies View Post
It would probably be easiest to pick a method (e.g. drift aligning with BYE, or using AlignMaster) and have a go - we can help you with any troubles you might have

As for the drift aligning with BYE... you need to centre the star and rotate the reticle like I described earlier - otherwise it won't work at all!

By the way, it is really really helpful to ensure that your mount is both (1) horizontally level, and (2) set up on firm ground that won't sink. Don't trust the bubble level on the mount (99.9% of them are incorrect from the factory) - you can use a bubble level or even a smart phone with a built-in inclinometer on top of the tripod plate. I find that setting up on grass or dirt causes no end of grief (one leg will inevitably gradually sink in), so I have a few Besser bricks half-buried into the dirt to keep things solid.
Thank you
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  #39  
Old 27-07-2013, 10:11 AM
alexV
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Update.

Can i just by saying that current update from Synscan is great.
I did polar alignment just under a min. It was supper easy.

With just polar alignment i have managed to get 1min and 40sec unguided.

But i think i still have the same problem. Because out of lets say 5 shots, 1 has drift.

Thank you
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  #40  
Old 27-07-2013, 02:08 PM
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What scope (and weight) do you have on the EQ5 Alex? They can be a challenge to get tracking well.
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