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Old 05-09-2020, 10:33 PM
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xa-coupe (Jeff)
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Chasing Polar Alignment

I finally cracked it tonight and am able to image out to 4 minutes with no trailing, though I'm taking it easy and limiting myself to 2 minutes..



Strangely, polar alignment was getting worse the longer I worked on it, despite getting as accurate as possible. I went from around 40 arc seconds up to about a minute 30... It then occurred me to park the scope, turn it off and start again. The alignment, first time around, was 23 and 24 arc seconds. I ran another alignment on different stars to be sure and the same.


I've never heard of it before, has anyone else?
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Old 07-09-2020, 01:10 PM
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that_guy (Tony)
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Which method of polar alignment have you used?
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Old 07-09-2020, 02:06 PM
Hemi
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Hi Jeff,

Yes I switch off the mount and set to home position between polar alignment iterations. You also have to do another alignment.

Im assuming your talking about the PA routine in the hand controller.

CS!

Hemi
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Old 07-09-2020, 02:37 PM
Wilsil (Wilco)
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Interested to hear as well what method you used.
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Old 07-09-2020, 03:49 PM
glend (Glen)
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What mount is this your using?
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Old 07-09-2020, 05:00 PM
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xa-coupe (Jeff)
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EQ6R, and handset polar alignment. I'll work on the drift alignment method shortly. I was trying to bust the back of my issues, which were all my not quite getting it. Hemi, thanks, I will do that. If it is 'how it works' then I will add that to the routine.



I am (finally) getting 360 second exposures with no trailing (900mm fl) so I've got it going well enough, along with guiding, to grab decent subs for the first time.
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Old 07-09-2020, 05:17 PM
Wilsil (Wilco)
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Good to hear.
Which stars did you pick? Is it as per Matins procedure, like Hadar and Atria?
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Old 09-09-2020, 06:26 PM
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I'm generally messing about trying to find alternate stars to the easy ones, such as Alpha Centauri, Hadr, the cruxs as they disappear behind the neighbours house quite early... so I usually use Alpha Centauri and Acrux ( early in the night) or Alpha Centauri and Antares (I think, I have it written down) later on. Usually by the time Alpha Centauri disappears I'm done or given up. I have a very narrow part of the sky to work with.... but it is enough.
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Old 09-09-2020, 07:02 PM
Startrek (Martin)
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Just remember Stars are constantly changing position so after a week or two the star you used for alignment a week or two ago may not be suitable now if you have to polar align again
The key to successful Synscan polar alignment is to ensure you select 2 stars close to the south meridian line ( within 20deg Az) both on the east side or west side and at an altitude between 35deg and 65deg. To achieve this you may have to wait for a certain time of the evening or morning to achieve this. Also the Stars you select should be the brighter ones.No point picking a dim star as your accuracy will be affected.
In other word you can’t just go out after dinner , plonk you’re Mount down and polar align using Synscan. Timing ( position) and Star selection is the key

A planetarium like Stellarium is an absolute must for Star selection , whether your using an illuminated centering eye piece or connected remotely to your laptop using Capture software with live view

Hope the above makes sense
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Old 10-09-2020, 11:51 AM
Craig_
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Give SharpCap a try for your PA routine, if you haven't already.
On the EQ6-R specifically, the alt/az knobs are extremely sensitive when dialing in minute adjustments.
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Old 10-09-2020, 12:16 PM
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"Just remember Stars are constantly changing position so after a week or two the star you used for alignment a week or two ago may not be suitable now if you have to polar align again, The key to successful Synscan polar alignment"




Stars do not change position stellar coordinates will not change in the space of a week of two. If you set up a mount permanently and attain perfect polar alignment you wouldn't have to realign for a considerable period of time
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Old 10-09-2020, 02:42 PM
Startrek (Martin)
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Quote:
Originally Posted by TrevorW View Post
"Just remember Stars are constantly changing position so after a week or two the star you used for alignment a week or two ago may not be suitable now if you have to polar align again, The key to successful Synscan polar alignment"




Stars do not change position stellar coordinates will not change in the space of a week of two. If you set up a mount permanently and attain perfect polar alignment you wouldn't have to realign for a considerable period of time
In relation to the fixed south meridian line or true south line , Stars sure do move. The reference was geared to mounts which have to be set up each time
“Not permanent”
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Old 10-09-2020, 02:57 PM
TrevorW
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stars do not move ok maybe over a long times, what moves is the earth, the south celestial pole and the north pole star are always in the same position relative to you. I go out tonight and find the pole star in 10 years it will be in the same position relative to my location



https://www.universetoday.com/85730/do-stars-move/

Last edited by TrevorW; 10-09-2020 at 04:20 PM.
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Old 10-09-2020, 03:14 PM
Startrek (Martin)
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Quote:
Originally Posted by TrevorW View Post
stars do not move ok maybe every few thousand years, what moves is the earth, the south celestial pole and the north pole star are always in the same position relative to you.

Totally agree with you about the movement of celestial objects in our Universe, but I'm trying paint a picture for a beginner who looks up at the night sky or his / her planetarium and notices that the star he was looking at 2 weeks a go has moved its position (I really don't care if its not scientifically correct) all I care about is helping these poor guys polar Align using their Synscan handcontrollers , the science and fact can then follow ( if their at all interested in that)
Cheers
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Old 10-09-2020, 03:41 PM
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xa-coupe (Jeff)
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I appreciate what you're saying Martin, as Orion disappeared from my view some time ago though I am pretty sure it's still where it is meant to be!
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