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How can I polar align when my yard faces south? Please don't say PHD2 drift align

Beginner Polar Alignment Software
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#1 Meowsolini

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Posted 20 September 2021 - 12:50 AM

Broke down the rig early tonight because I've been trying to get polar aligned for nearly 4 frustrating hours with no real luck. I got somewhere that I thought was close enough, but PHD2 guiding was absolutely horrible when I was getting ready to do some imaging. The red and blue dec and RA lines were chaotic, zigzagging above and below the chart with every correction. I tried recalibrating, then PHD2 gave me a warning saying my dec and RA have too large of an error between them or something like that, suggesting poor polar alignment (I don't remember exactly what it said).

 

My view of the sky is pretty limited; my yard faces south (I live in the northern hemisphere), and I have two large trees on either side of me.

 

The first thing I always try is using my EQ mount's three star polar alignment feature. I point it at three different stars and it tells me how many degrees west or east my azimuth is, and how many degrees low or high my altitude is. Problem is I don't know how many degrees it's turning when I'm turning the knobs. (There's no guide or markings to indicate it). It's also super tedious slewing to Altair, Deneb, and Vega over and over again.

 

I've also been trying to use PHD2's drift align function, but when I slew to its recommended coords for the altitude adjustment, it points directly to a tree. So that does me no good. The trendlines also seem wildly inconsistent to my adjustments.

 

I've also tried the polar alignment plugin for NINA, but it never makes it past the 2nd step (nothing happens. No error message or any change on the screen). Tried it multiple times. Useless.

 

 

I'm sick of battling janky astronomy software which seems to just add more complications to the problem. Ideally, I'd like to be able to get aligned without a computer. Just the scope, mount, its hand controller, and two eyes. People have done this before computers, right?

 

I have an 805mm refractor telescope, an iOptron GEM 45 EQ mount, an Orion 60mm guide scope, a Meade guide camera, a green laser, and a QHY mono astronomy camera.

 

 

Some nights are luckier than others where I can get aligned in two hours through trial and error, and PHD2 runs relatively smoothly. Other nights are like tonight where nothing wants to work.

 

 

My mount is level. The mount's zero position is correct. The front yard is way too bright from the street lights, and I can't afford a battery and all the extra equipment I would need to make a portable setup.

 

 



#2 mehdymo

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Posted 20 September 2021 - 01:29 AM

I would roughly face north, go to a star by goto, and put the star in center of field by mount's Alt and Azimuth knobs.This way your aligment should be very close. After that you can follow other methods to make it more accurate.

 

Rmemeber to:

- align the polarscope

- make the scope parallel with polarscope. You can shim the scope until a constant object like polaris is in the center of both of polar scope and scope.

-  make sure all paramaters are correct on your hand controller such as date, time, location, tracking speed and etc.

- level the mount

- your zero position should be accurate.


Edited by mehdymo, 20 September 2021 - 01:30 AM.

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#3 dswtan

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Posted 20 September 2021 - 01:29 AM

I have similar location issues and similar no luck with PHD2’s method. NINA’s worked great for me and got me closer than I’ve ever been in this location. Since the software is regularly updated in alpha quality, which I normally avoid, it pays to give NINA another shot since you already tried it and you’re running out of (assisted) options.


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#4 robbieg147

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Posted 20 September 2021 - 02:11 AM

It's not cheap but the MGEN 3 standalone auto guider will get you polar aligned pretty quickly, though I have not used mine for this as I use the Polemaster. It will also guide for you at the push of a button if you are not getting on with PHD2.


Edited by robbieg147, 20 September 2021 - 02:11 AM.


#5 Wilsil

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Posted 20 September 2021 - 02:12 AM

The first thing I always try is using my EQ mount's three star polar alignment feature. I point it at three different stars and it tells me how many degrees west or east my azimuth is, and how many degrees low or high my altitude is. Problem is I don't know how many degrees it's turning when I'm turning the knobs. (There's no guide or markings to indicate it). It's also super tedious slewing to Altair, Deneb, and Vega over and over again.

This is exactly how it did it before I used SharpCap and NINA.

Yes, it takes time but it works.

Start with aligning your mount as good as you can to true North (in your case).

I also noticed that you have to pick the right stars for the 3 star alignment.

Set the camera to loop, go to the first star and follow the prompts (center the star in your screen). It sounds like you know how it works.

Don't give up. It took me a while before I got it.


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#6 Phishin_phool

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Posted 20 September 2021 - 06:53 AM

Try adjusting the variables in Nina 3 point pa. Also make sure you are not using astrometry as your plate solver (I use ASFAP). Astrometry is too slow to solve for NINA'S algorithm

#7 Alex McConahay

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Posted 20 September 2021 - 07:46 AM

>>>>>>but when I slew to its recommended coords for the altitude adjustment, it points directly to a tree.

 

Drift alignment need not be done at the coordinates suggested by PHD2. It picks those coordinates because the errors show up fastest there. But the errors will show anyplace in the sky eventually. I would suggest that if your scope is pointed to a tree when PHD2 sends the scope to the eastern horizon, you instead just move the scope to the western horizon, about the same altitude. If you have a different tree or obstacle, just move the scope up in altitude, while still pointing east (or west) and do your alignment there. You are still looking only for north or south drift. 

 

>>>>>>The red and blue dec and RA lines were chaotic, zigzagging above and below the chart with every correction.

 

First off, they will be when they first start out......you have to give them a minimum of two minutes to settle down, I find. And, really, you want to consider maybe four to five minutes before making adjustments again. Secondly, you are adjusting too much each time. YOu need to adjust ever so slightly. Somebody once described it a touching the knob, and then just "thinking" about adjusting it. That is enough of an adjustment. Of course that is a bit of an exaggeration. 

 

 

>>>>>>Problem is I don't know how many degrees it's turning when I'm turning the knobs.

Actually, you can figure that out.....and which knob turns it which way, and how much backlash you have in each turn of the knob. But, the point is, once you have gotten it fairly close, it is only a very slight movement in each case--not even enough to be considered a turn of the knob, to get it where it belongs. And with every tweak of the knob, you will start that exaggerated movement back and forth (until it settles down after a couple of minutes). 

 

I think what helps most is not thinking of turn knob this way to go north/west, etc. but to just realize that pushing the knob this way slows the error line, pushing it that way speeds it up (makes it move closer or further from the flat line you are looking for). And go from there. 

 

Patience is key to this while you are practicing. And it is easier to be patient if you are not trying to polar align for an evening of imaging. Now that the moon is up and would ruin any deep sky picture you want to take, go out a few times JUST to learn polar aligning. That is, just mess with polar alignment without hoping to get it good enough to image. Experiment. Play with how much turning a knob changes the report you get in your three star alignment, and all that!

 

And if you can find a guru, go for it. Somebody who knows what is happening can show you some tricks. If you can make it to a star party with other imagers would be ahead of the game. 

 

Good luck.

 

Alex


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#8 kathyastro

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Posted 20 September 2021 - 07:54 AM

If all the software alignment methods are giving you trouble, try drift aligning without software.  You need a reticle eyepiece and a bit of time, but it is what people did before all the newfangled electronic stuff.  The nice thing is that you get to pick your own alignment stars.


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#9 dx_ron

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Posted 20 September 2021 - 09:08 AM

The Ekos polar align routine works using 3 images rotated in RA, but supposedly at any declination. I have never tried it actually pointing south so I can't swear it really works, but I use it at Dec 40-50N all the time.

You don't have access to Ekos, but surely one of the Windows-friendly alignment apps has that capability?


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#10 jonnybravo0311

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Posted 20 September 2021 - 09:16 AM

The Ekos polar align routine works using 3 images rotated in RA, but supposedly at any declination. I have never tried it actually pointing south so I can't swear it really works, but I use it at Dec 40-50N all the time.

You don't have access to Ekos, but surely one of the Windows-friendly alignment apps has that capability?

NINA has the 3 point polar alignment plugin in the nightly builds. That was summarily dismissed by the OP as "battling janky astronomy software".


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#11 sbharrat

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Posted 20 September 2021 - 09:56 AM

 

...

 

I've also tried the polar alignment plugin for NINA, but it never makes it past the 2nd step (nothing happens. No error message or any change on the screen). Tried it multiple times. Useless.

 

 

I'm sick of battling janky astronomy software which seems to just add more complications to the problem. Ideally, I'd like to be able to get aligned without a computer. Just the scope, mount, its hand controller, and two eyes. People have done this before computers, right?

 

...

If you get it done the old school way, congrats!! If you go back to thinking maybe computers/software might be helpful in this hobby, there is another alternative within NINA. It's the PA tool on the imaging pane. Not as automated as the plugin but uses only the very basics so less likely to fail. Point south. NINA will take a pic, platesolve, move the moutn a bit, take another pic and platesolve. Then it will tell you how far left/right to move the azimuth adjustment. Repeat pointing either east or west for altitude adjustmanet. 

 

(I am assuming that your NINA setup is functional enough to move the moutn, take an image and platesolve already. If your computer woes extend this far, then ignore this post.)

 

nina-pa.jpg


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#12 Forward Scatter

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Posted 20 September 2021 - 10:08 AM

++++1 on NINA's Three Point Polar Align plugin. Very easy to use and accurate. 

 

I've imaged extensively with the latest nightly build and have found it to be extremely stable and functional (and free). If one has concerns about NINA nightlies in general, I suggest just downloading the suite, installing the plugin and use it only for the TPPA. Then close it down and use one's usual acquisition software. 


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#13 ChiTownXring

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Posted 20 September 2021 - 10:15 AM

With what ever method you use, once you get close or are happy with your PA do yourself a favor and mark the ground so you can put the tri-pod back on the same marks and you will be very close to PA every time out..

I have my marks on my deck and can be PA in about 30 seconds because I am always very close..


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#14 KungFood

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Posted 20 September 2021 - 10:39 AM

I'll echo part of what Alex said. You don't need to be spot on for PHD2's drift to work, I don't even bother with its coords. I start with a spot in the southern sky above the equator and east of the meridian. I'm forced further southeast than is ideal by what I'm sure is a sentient tree hat moves closer every day. Then a spot as far east along the equator as the neighbor's garage will allow. Make notes in PHD2's drift tool so that you don't have to trial and error or remember what adjustment does what. I have a very very narrow slice of sky to work from, but I'm still able to guide at sub arc second for 300 sec subs easy. It just takes 20-30 mins to align, and gets easier with repetition. Welcome to the non ideal sky view club! smile.gif

 

 

*Edit*  -  It's worth it to get practice at drift aligning either way. I went out to the dark sight recently, and forgot the cable for my Polemaster at home. Having recently put the time in learning drift aligning from my backyard saved the night. takes a bit longer than other methods, but it works, and is actually the most accurate method for PA if done in an iterative manner, I believe, because it is based on actual star movement in the FOV (I could be wrong).


Edited by KungFood, 20 September 2021 - 11:06 AM.


#15 Alex McConahay

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Posted 20 September 2021 - 12:09 PM

One other thing that can speed polar alignment. 

 

I forget the exact details (I don't use it), but I know many other imagers vouch for it. They will pitch in here to give you the details. It is called DARV. 

 

It involves starting an exposure, and then reversing the mount, or something. Check it out:

 

On Edit---a better link:

 

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

Alex


Edited by Alex McConahay, 20 September 2021 - 12:11 PM.


#16 pedxing

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Posted 20 September 2021 - 04:25 PM

You can still use PHD to drift align without using the drift align tool.

 

Just turn on the grid and set it to a fine grid. Then when you are pointing east/west, you can watch a star drift against the grid (you pay attention to one direction of the drift while ignoring the other direction).

 

This is the same as what people used to do with a reticle, but phd gives you an electronic reticle to work with and you aren't hunched over the scope the whole time.

 

I used to image from a location where polaris was behind some trees, and I would use this method to get things close, then switch to the drift alignment tool and make final adjustments. Like Alex said, these will be "breath on the knob" kind of adjustments. I also think the advice to just work on your drift alignment technique on a full moon night without worrying about imaging helps. You really do have to be patient and wait for everything to settle before adjusting the knobs.

 

Something that can be a complicating factor is your seeing. If you have poor seeing, drift alignment can feel like a fool's errand. But that's pretty much true with any polar alignment method. I've had nights where it was next to impossible to polar align with a polemaster because of bad seeing...



#17 1DegreeN

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Posted 20 September 2021 - 10:23 PM

PHD's drift alignment can be frustrating the first few times you try it. Like everything in this hobby it needs patience and persistence and a systematic approach. What I did was, on the first night, I drift aligned for both altitude and azimuth. This took a long time, there's no way around it. I marked the position of the tripod legs on the ground and made very sure not to change the mount's altitude adjustment when packing the mount away and setting up again. My tripod legs are fixed length so that is not a factor I have to worry about. Then on second and subsequent nights I use drift alignment just for azimuth adjustment - I assumed the altitude was still good. Drift alignment for azimuth only can take anywhere between 5 and 20 minutes - it will improve with experience as you develop a feel for how far, and in which direction, to adjust the mount's azimuth bolts to correct the drift. I had 3 rigs aligned like this and ran them for a year before checking the altitude again. 



#18 Alex McConahay

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Posted 20 September 2021 - 10:48 PM

>>>>>Then on second and subsequent nights I use drift alignment just for azimuth adjustment - I assumed the altitude was still good.

 

I would assume so too. But, every now and then you should check it. It should take hardly any time at all---maybe four minutes, a couple to let PHD2 graph calm down, and another couple to confirm the direction of the line. After all, if you do not need to do any adjusting (because your assumption that it is good is true), it does not take much time!!!

 

 

Alex



#19 bobzeq25

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Posted 20 September 2021 - 11:18 PM

Broke down the rig early tonight because I've been trying to get polar aligned for nearly 4 frustrating hours with no real luck. I got somewhere that I thought was close enough, but PHD2 guiding was absolutely horrible when I was getting ready to do some imaging. The red and blue dec and RA lines were chaotic, zigzagging above and below the chart with every correction. I tried recalibrating, then PHD2 gave me a warning saying my dec and RA have too large of an error between them or something like that, suggesting poor polar alignment (I don't remember exactly what it said).

 

My view of the sky is pretty limited; my yard faces south (I live in the northern hemisphere), and I have two large trees on either side of me.

 

The first thing I always try is using my EQ mount's three star polar alignment feature. I point it at three different stars and it tells me how many degrees west or east my azimuth is, and how many degrees low or high my altitude is. Problem is I don't know how many degrees it's turning when I'm turning the knobs. (There's no guide or markings to indicate it). It's also super tedious slewing to Altair, Deneb, and Vega over and over again.

 

I've also been trying to use PHD2's drift align function, but when I slew to its recommended coords for the altitude adjustment, it points directly to a tree. So that does me no good. The trendlines also seem wildly inconsistent to my adjustments.

 

I've also tried the polar alignment plugin for NINA, but it never makes it past the 2nd step (nothing happens. No error message or any change on the screen). Tried it multiple times. Useless.

 

 

I'm sick of battling janky astronomy software which seems to just add more complications to the problem. Ideally, I'd like to be able to get aligned without a computer. Just the scope, mount, its hand controller, and two eyes. People have done this before computers, right?

 

I have an 805mm refractor telescope, an iOptron GEM 45 EQ mount, an Orion 60mm guide scope, a Meade guide camera, a green laser, and a QHY mono astronomy camera.

 

 

Some nights are luckier than others where I can get aligned in two hours through trial and error, and PHD2 runs relatively smoothly. Other nights are like tonight where nothing wants to work.

 

 

My mount is level. The mount's zero position is correct. The front yard is way too bright from the street lights, and I can't afford a battery and all the extra equipment I would need to make a portable setup.

In rough order of importance, from most to least.

 

What you describe is not bad polar alignment.  Bad polar alignment causes DEC drift (which can be corrected by guiding, but guiding is imperfect, the less you guide the better).  Or maybe some frame rotation, causing funny shaped stars.  Not chaotic guiding graphs.

 

You need to post _exactly_ what PhD2 is saying is wrong, start to finish.

 

What people used before computers is polar alignment scopes.  But they require a view near Polaris.

 

Almost every good imager uses a computer.  They take the load off you of mundane chores.  They let you point to a target much more reliably than GOTO.  They let you monitor what's coming in.  And they're absolutely esssential for running an astro camera, which has little intelligence of its own.  By the time you use one for all that, using it for good polar alignment is a small addon.

 

Mount level is unimportant, as long as it doesn't topple over.

 

Zero position affects GOTO, not guiding.

 

The three star alignment is not for polar alignment, it's for GOTO.  The Polar Iterate Align is for polar alignment.  It doesn't give you a value or value of anything, you're just trying to center stars.

 

But you have bigger problems than polar alignment.  Sorry.


Edited by bobzeq25, 20 September 2021 - 11:21 PM.


#20 DJL

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Posted 20 September 2021 - 11:38 PM

Back to the front garden: try putting up a shade to get between you and the streetlights - Chuck of Chuck's Astrophotography does this. As long as they are not between the scope and Polaris, and not shining into the scope, it may be better.

I wouldn't be doing this if it was taking 2 hours to polar align :-)



#21 EdDixon

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Posted 21 September 2021 - 03:04 AM

There are other ways that can get you pretty close to PA with no scope or view.  How close depends on what you need for your session.  Imaging is different from visual and long focal length scopes compared to wide field views.  With a simple device you can do a pretty good PA in broad daylight...which also works well at night.  This approach does not depend on a view of the sky at all...trees or not.

 

The device is a 3D printed iPhone holder made just for this.  You can download the specs for it on Thingiverse.com. 

 

https://www.thingive...m/thing:4564325

 

I have a rocket friend who has a 3D printer who made it for me.  I use an iPhone app called PS Align Pro.  It works well and has many other options.  I have used it with a few mounts and it does well.  I use it to get things close before I do more accurate PA things with either a regular polar scope or a specialized camera like PoleMaster or iPolar.  For some wide field situations, it may be completely sufficient.

 

Others who use this same method made their own iPhone device using nothing but a piece of wood and rubber bands.  With either device doing a “close” PA takes less than 2 minutes.

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#22 robbieg147

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Posted 21 September 2021 - 04:40 AM

PHD's drift alignment can be frustrating the first few times you try it. Like everything in this hobby it needs patience and persistence and a systematic approach. What I did was, on the first night, I drift aligned for both altitude and azimuth. This took a long time, there's no way around it. I marked the position of the tripod legs on the ground and made very sure not to change the mount's altitude adjustment when packing the mount away and setting up again. My tripod legs are fixed length so that is not a factor I have to worry about. Then on second and subsequent nights I use drift alignment just for azimuth adjustment - I assumed the altitude was still good. Drift alignment for azimuth only can take anywhere between 5 and 20 minutes - it will improve with experience as you develop a feel for how far, and in which direction, to adjust the mount's azimuth bolts to correct the drift. I had 3 rigs aligned like this and ran them for a year before checking the altitude again. 

I would be surprised if this worked reliably? the other thing you could do that may help is to just release one azimuth bolt when you pack away, then when you set up tighten only the bolt which you loosened, but I would always check myself.



#23 Cliff Hipsher

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Posted 21 September 2021 - 08:06 AM

Even though I have an unobstructed view of the NCP, I have been dealing with similar issues with an LXD75 and Autostar.  I could get "close" but not quite close enough, so I decided to wipe the slate clean and start over.

 

I set my rig up in the front yard.  I have three concrete slabs.  While I was checking  the alignment of the N-S slab I had an epiphany: I was using MAGNETIC North..   That introduced a 10+ degree error to the West... And I got to thinking...  The mount has latitude, azimuth, and level  adjustments that could be "off" as well.  After I got my slabs reset, I tackled the mount and the first item was Level.

 

I am using an AstroZap eyepiece tray that has a round spirit level on one side of the tray.  Using the tray level I "leveled" the mount and then I checked it with a separate level.  Low and behold, the mount was NOT level.  As it turns out the tray is bent ever so slightly.  To fix this I added two spirit levels.  One level is attached to the front (North side) of mount head over the latitude and azimuth adjustment knobs. This indicates "East/West" level. The other level  is attached to the right(West) side of the mount directly under the Latitude dial.  This indicates North-South level.  Now that I have that figured out I went to the Latitude Adjustment.

 

This one is a little trickier, but not impossible.  I can use my smartphone...  All I needed was two apps, one for GPS coordinates and one for Inclination...  Armed with those tools it took me all of 5 minutes to set Latitude.

 

Now that I KNOW the mount can be setup up properly,  all I need is a clear sky...

 

Attached pictures show how much error is in the round level.

 

20210921_080017.jpg 20210921_075952.jpg 20210921_080035.jpg

 



#24 DRK73

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Posted 21 September 2021 - 08:59 AM

There used to be a program called AlignMaster which was great for polar aligning if you couldn't see Polaris. As long as you had a mount that could be controlled via ascom then it worked pretty well. 



#25 Phil Sherman

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Posted 21 September 2021 - 09:09 AM

This month's (dinosaur on the cover) Sky and Telescope has an article that partially describes the DARV polar alignment technique with one minor error. After a rough polar alignment, you set the mount to track and slew at sidereal rate and take a 70 second exposure without guiding. During the exposure you let the mount track for 5 seconds, slew E for 30 seconds then slew W for 35 seconds. As discussed in the article and shown in the photos, you'll see the bright star from the tracked portion with a V shaped tail that, using my slew times, will go a bit passed the star. You adjust the mount until the V collapses into a line that passes back through the center of the star.

 

The celestial equator near the meridian target is used to adjust the azimuth while the celestial equator 20-30 degrees above the E or W horizon is the target area to adjust the altitude. Once you become familiar with the relationship between the location of the V tails vs the needed direction of adjustment, polar alignment should take less than 15 min.

 

The S&T article states to slew W first which is incorrect. The first slew should be E. An E slew at 1x sidereal causes the mount to stop tracking, keeping the gears engaged for the W slew. An advantage of the DARV technique is that you can easily compare the current image with the previous one to determine the effect of an adjustment. The sensitivity of the tests can be doubled by using a 130 second exposure and 60 E, 65 W second slews. A 1/4 pixel drift is easily visible in the image when the W slew passes back through the initial 5 second tracked bright star. There's also no need to locate a bright star for the images because there will always be some stars visible in it.


Edited by Phil Sherman, 21 September 2021 - 09:10 AM.

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