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Drift Align Methodology for Dummies with DSLR in BYE?


ANKulin
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I am wondering if anyone has a detailed guide that explains how to set up and perform a drift alignment using a DSLR mounted on a star tracker?  I have Canon DSLRs that I mount on a Lightrack II tracker that I use up at the cottage.  Our cottage faces south and is heavily treed.  I have a Polemaster that I use for polar alignment but with limitations.  In winter I can go out onto the lake and do my alignment and point in any direction I want.  But when there is no ice, from the only location on land that I can set up with a view to Polaris limits my views from north to north east and straight up.  I cannot do anything to the south during the spring, summer and fall, though I could if I did not need Polaris to align. 

Some specific things that are confusing to me are:

  1. How to properly set up the drift align reticule in BYE?  I know how to rotate it in the software but do I line it up on any star with the tracker running, then stop tracking and adjust the rotation of the reticule so that it is parallel to the motion of the star as it moves across the screen?  Do I only do this at the beginning of my setup or do I need to do this a few times, particularly if I need to make big adjustments to RA or declination?
  2. This is a big point of confusion for me, that I have a brain blockage for and cannot figure out.  I have found many articles on drift alignment and/or DARV (which won't work for my setup because I cannot slew), but I am pretty sure they are written assuming one is using a telescope where images are upside down.  For example here is an instruction about drift alignment for a telescope I found:  "If the star drifts NORTH with respect to the cross hairs, the telescope azimuth is pointing WEST of NORTH. Use the azimuth adjustment on the mount to turn it a small amount to the EAST."  Here is where I get totally confused.  Is NORTH up in your eyepiece, or because everything is upside down in the telescope eyepiece, down?  What would be extremely helpful here would be clear instructions specific to BYE and DSLR views (which are not inverted) that tell me if star moves UP/DOWN then adjust RA (or declination) in DIRECTION/OPPOSITE DIRECTION.

Thanks,

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Most people have moved away from the traditional drift alignment method. BYE does not impose nor propose a way to do it, it just uses your computer screen as the camera "LCD" to aid you in whatever process you have.

This said, you should probably look at PHD for drift alignment, or consider a PoleMaster.

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I do have a Polemaster but my issue is I cannot do any imaging to the south except in the winter when the lake is frozen and I can set up on the lake and see Polaris.  During the remaining 10 months of the year, to shoot to the south I would need to set up along the shoreline and there are trees to the north so I cannot see Polaris at all, thus my question about Drift Align.  It would be similar to a situation where someone has access to a condo balcony that only faces south.

I am not requesting that BYE do the drift alignment as I realize that it is basically using the camera live view function and overlaying an alignment reticule.  What I am looking for is input from BYE users as to how to apply the drift align method using a DSLR and BYE.  My first bullet is simply asking how to properly align the cross hairs on the reticule so they are properly oriented N-S and E-W and if what I think is the way to do it correct or not?  And my second question relates to how to interpret the drift depending which way the star moves relative to the targeting cross-hairs as I am having a complete mental blockage on how to convert instructions for drift align based on viewing an inverted image in a telescope to viewing the image through the camera via BYE on screen.

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Without being able to slew it will be difficult to adjust the rotation of the reticle so that the horizontal crosshair is parallel to the direction of tracking. And without being able to see Polaris I am not sure how you can get a rough polar alignment either.

Here are the basics of drift alignment.:

When the mount is not polar aligned, the mount will drift in declination, either up or down.

Position the mount so that it is pointing near the intersection of the Meridian and the Celestial Equator. Pointing in this part of the sky means that the greatest contributor to drift is misalignment of the mount in azimuth. Watch how a star in the field-of-view drifts over time. Move the mount in azimuth, re-center the star and continue to watch it. If it is drifting faster, then you moved the azimuth in the wrong direction. Continue making small adjustments to the azimuth to minimize the drift as much as possible.

Then change your pointing position to the east along the Celestial Equator until you are about 30 degrees above the horizon. Now watch the drift and adjust the mount in altitude to eliminate the drift. Note that if the drift rate increases, then adjust the mount in the other direction in altitude.

If your alignment was way off when you started then you may want to repeat from the beginning to fine-tune the alignment

You should be able to position the mount, as necessary, by loosening the ball joint and swiveling just the camera to another part of the sky. If you want to use BYE's Drift Align reticle to help you see the drift more easily, then you just select the Drift Align function and rotate the reticle so that the horizontal leg of the crosshairs is oriented in the direction of tracking. Once the reticle is roughly aligned with the direction of tracking, drift will be up and down, along the vertical leg of the  crosshairs.

The advantage of PHD2's drift alignment is that it is constantly downloading images from the guide camera and measuring the amount of drift. BYE doesn't have this measurement capability.

 

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