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Questions about drift alignment for a newbie

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#1 TonyCaf

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Posted 13 August 2019 - 01:34 AM

Hello everyone.

 

I am at that point where I must learn how to do drift alignment. I have read three or four methods and had specific questions regarding the orientation of the reticle when starting the process. The way I understand it is after choosing a star near the celestial equator in the south (close to the meridian) I have to orient the reticle so that the star travels more or less parallel along one of the lines in the reticle. If i do this while adjusting declination back and forth have I found the North/South direction? I hope I am making sense here! Also, will this final orientation bear any relationship to the horizon? Or will it be skewed or haphazard? Lastly does it make a difference if I use a right angle?


Edited by TonyCaf, 13 August 2019 - 01:39 AM.


#2 kathyastro

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Posted 13 August 2019 - 06:14 AM

To orient the reticle, find your star and then turn off the tracking.  Let the star drift.  Orient the reticle so that the star is drifting parallel to one of the lines.  Ideally, for maximum accuracy, adjust the aim so that the star is drifting along the line.  The reticle is now oriented for drift alignment.


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#3 TonyCaf

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Posted 13 August 2019 - 06:32 AM

Thanks so much for the suggestion. So from what I gather there is no special orientation of the reticle other than that of aligning it to one axis of the crosshairs. Now if I do that with the star on the meridian near the celestial equator, that would be my north south line right? Sorry if I am a bit confused but I have only practiced this alignment in theory and want to be as clear about it before I go out tonight and actually try!



#4 kathyastro

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Posted 13 August 2019 - 07:29 AM

There is a specific orientation for the reticle.  When you are setting up the reticle so one of the lines is parallel to the star's drift, you are aligning it east-west.  The other line, at right angles to the first, is north-south.

 

Drift is always east-to-west (even if it doesn't look horizontal).  A line perpendicular to the east-west line is north-south.  It doesn't matter if you do this on the meridian or to the east or west, or anywhere else.

 

Once you have the reticle oriented, lock it in place and then begin your drift alignment.  At that point, it does matter whether you are pointing at the meridian or to the east or west.  You point east (or west) to adjust elevation, and at the meridian to adjust azimuth.


Edited by kathyastro, 13 August 2019 - 07:32 AM.

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#5 TonyCaf

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Posted 13 August 2019 - 07:31 AM

Ok thank you for clearing up the confusion. I will try this tonight and report back!



#6 Phil Sherman

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Posted 13 August 2019 - 08:18 AM

You can drift align within much less time if you use your camera to do it. Check out this reference.

 

https://www.cloudyni...bert-vice-r2760

 

If you extend the exposure to 130 seconds and the second slew to 35 seconds, it's a lot easier to determine that the two trails are coincident.



#7 TonyCaf

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Posted 13 August 2019 - 08:34 AM

Wow, this sounds a lot easier. Thanks, now i'm not sure which method to try tonight!



#8 Starman27

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Posted 13 August 2019 - 11:23 AM

Wouldn't hurt to try them both.




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