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coenie777

Battling with polar alignment. Help please!!

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For starters, I live in the Southern Hemisphere under mag 4 skies.

I had my NEQ6 mount now for two months during which time I managed to ONCE take images of around 45 sec to 1 min without trailing.

The rest of the time I am battling to just figure out if the stars in the polar scope I am looking at are even the right ones. I am now concerned that maybe my mount did not like me adjusting the stepper motor's gear play or something.

For the life of me I cannot get even 20 sec exposures going now. I am trying to use AlignMaster but as per the usual complaints, I cannot see both stars it selects and as such now resort to hours of trying to see the Octans constelation I need for alignment.

Would it be possible to tell from my latest pictures if there is something wrong with my mount? When I did a 120sec exposure to see what the trails look like, I got this weird kink in the star trails. Does this look like something normal if you are now well aligned, or could there be a problem with the mount?

I also include a 45 sec exposure. Here the star trails seem to make a zig zag motion.

Any advise or would you say it is just bad alignment?

120sec exposure

120seca_zps73764c64.jpg

45 sec exposure

45seca_zps44804cf7.jpg

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Does the NEQ6 run with a Synscan handset? If so, you can do a rough Polar Alignment with the polarscope. Next do the 2 star alignment procedure followed by the Polar Alignment procedure for one of the stars you chose in the 2 star alignment. Repeat this a couple of times and your Mal/MAZ error should be below 1'. This is good enough for a couple of minutes exposure at least without guiding.

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The only suggestion I would make is to ensure your alignment is really accurate, if you don't already, align with a really accurate ep in which the centre point is marked, ie illuminated reticule, if you don't already use one, you probably be very pleasantly surprised how much more accurate the whole set up works.

Whatever the solution, hope you find it soon :-)

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The kinky stars do look odd, I would guess either someone walked past the mount or it shifted on its own.

The gear play should not effect the tracking (unless you tighten it up so much it can't move!) as for unguided tracking the RA motor only turns one way.

Sent from my iPad using Tapatalk

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Connect up your neq6 to a computer and use it to assist your polar alignment using something like AstroTortilla that doesn't need you to use specific stars.

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Connect up your neq6 to a computer and use it to assist your polar alignment using something like AstroTortilla that doesn't need you to use specific stars.

Does AT work without guiding? I didn't notice the OP listing guiding kit.

In general, polar misalignment results in DEC error. This is usually side to side errors in the frame, while tracking errors show in the frame  as vertical errors (RA). A bit of both seems likely here. If you know the period of rotation of the worm drive gear/pulley, example 10 minutes, take 10 x  2 minute subs and see if the amount of error regularly increases and decreases in time. This will show the extent of PE if it matches a multiple of the period.

Check your balance. Regardless of the location , east or west of the meridian, the aperture end of the scope/camera should be heavy slightly with DEC clutch released. Then check pointed at a target east of meridian and RA clutch released. CW end should be slightly heavy, and vice versa for targets west of meridian.

I realize, none of this will help you achieve PA, but it may help with some of the trails.-Jack

Edited by kalasinman

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Thanks for the replies.

I tried some of the suggestions already and started to see improvements. Getting close to 2 min on 400mm fl now. Will continue tweaking until I can get at least 2 min on the 800mm fl.

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With out going through the procedure of setting up the mount there are a couple of simple checks that can be made.

Set the telescope so that the Dec = 0 degrees.

Rotation of the RA should point to stars on the celestial equator.

At this time of the year you should be able to point accurately to

zeta-1-Aqu (picture attached). It is very easy to find (look for a steering wheel )

the 3 stars, alpha, zeta and eta lie on the celestial equator.

If you stay up the next bright star will be delta-Ori.

These stars are much easier to use than sigma-Oct.

If you wait for these stars to transit you will get an excellent

idea of your polar alignment

post-37798-0-65152000-1412934663_thumb.j

Jeremy

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Thanks Jeremy!

A fellow Southern Hemisphere'er :laugh:

I will try out those stars. As luck would have it looks like a cloudy weekend, but the first chance I get...

Coenie

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Sorry if someone said this already ( i didn't read all the post).  What kind of camera are you using, if it has a live view hook up a laptop and learn to drift align.  It works regardless of hemisphere and once you learn how to do it, it doesn't take long.  

Check out the last half of this video

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Thanks mballak, I have that video downloaded already I think. Will check out the last bit as I suspect drift aligment might do the trick.

I have astrotortilla that can automate this apparently as well.

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