Finding Polaris?

Started 11 months ago | Questions
starman1969
starman1969 Veteran Member • Posts: 4,411
Re: Finding Polaris?

This might help.

If your tripod head or wedge has a degree scale, you can set it during the day, which will hopefully get you very close to Polaris without having to fumble around in the dark, making it a little easier to find. Use a compass to get the azimuth direction, and then the declination scale on the head for the height. If it doesn't have a scale, you could make one.

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Dr_Love
Dr_Love Contributing Member • Posts: 844
Re: Finding Polaris?

landscaper1 wrote:

I've owned an iOptron SkyTracker Pro for some time and would like to be able to use it.

When I last made the effort (some time ago) I gave up because I found it all but impossible to locate Polaris through the optical sight in the SkyTracker. To begin with, because of light and air pollution I rarely can see Polaris even though I know the approximate area in the sky where it's located.

Does anyone have a suggestion on how to get around this obstacle? Or am I doomed to forego using a tracker anywhere other than exceptionally clear night skies?

I'm not trying to be a (insert nasty name here). I'm just trying to use a little logic to identify where the problem is.

FIrst off, if you can physically see the big dipper, you can see polaris. Please note I did not say locate, I said see. This suggests to me either technique or hardware are the problem. You seem to understand the concept of how to find polaris but are still having difficulties locating it with the scope. Can you locate it without the scope on your own? If you can and you haven't spent much time with waist level or 90 degree finders, I might suggest you get rid of that 90 degree eyepiece and look straight through for a normal non-reversed image. I had a terrible time when I first started using MF waist level finders and the only thing to make one competent is more time using it. I know this may sound like a long shot but I like to think a little outside the box.

Edit: If you can't physically see polaris, depending on where you are, it is possible that it is so low in the sky that it can't get past the intensity of the airglow and/or light pollution

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davecac Regular Member • Posts: 177
Re: Finding Polaris?

Would a bevel box be any help . They are accurate to 0.1 degree so may work . Dave

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Bill Ferris
Bill Ferris Veteran Member • Posts: 6,185
Re: Finding Polaris?
1

starman1969 wrote:

This might help.

If your tripod head or wedge has a degree scale, you can set it during the day, which will hopefully get you very close to Polaris without having to fumble around in the dark, making it a little easier to find. Use a compass to get the azimuth direction, and then the declination scale on the head for the height. If it doesn't have a scale, you could make one.

A magnetic protractor is a cheap and easy solution to setting the tilt angle of the mount to the local latitude.

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mermaidkiller Senior Member • Posts: 1,094
Re: Finding Polaris?

Bill Ferris wrote:

A magnetic protractor is a cheap and easy solution to setting the tilt angle of the mount to the local latitude.

How does that work ?

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Bill Ferris
Bill Ferris Veteran Member • Posts: 6,185
Re: Finding Polaris?

landscaper1 wrote:

bmike wrote:

How long or wide of a lens are you using?

When I haven't been able to see Polaris with wider lenses I did the following:

1. Level tripod.

2. Adjust declination based on your latitude.

3. Point North with compass (adjust for magnetic declination). My tracker has a declination / compass mount for it.

Then, if using a long lens, or needing really long exposures, once it gets dark sight through the scope... but if you are in heavily light polluted areas a long exposure might just blow out your image.

I'm using a Vixen Polarie - so I also open SkyWalk2, search for Polaris, then put the phone on the back of the mount, and tweak (if needed). Now that I have a polar scope for it I do steps 1-3 and sight through (assuming I can see Polaris...)

You might have to wait until you can travel a bit and get out of the city though, if you are having trouble seeing.

Mike,my problem is with the SkyTracker Pro's own optical (1x) sight. It has a fairly narrow field of view.

Attach a laser pointer to the mount and align it with the optical sight.

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Bill Ferris
Bill Ferris Veteran Member • Posts: 6,185
Re: Finding Polaris?

mermaidkiller wrote:

Bill Ferris wrote:

A magnetic protractor is a cheap and easy solution to setting the tilt angle of the mount to the local latitude.

How does that work ?

I used one for many years with a German equatorial mount. The protractor has a magnetic base that will affix it to a flat metal surface and will indicate the tilt angle of the mount. The celestial pole's elevation above your local horizon is equal to your local latitude. Set the tilt of the mount to your local latitude.

The final step is to set the mount's azimuth equal to true North. This can be done with a compass as long as you offset for the deviation of magnetic North from true North for your locale.

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davecac Regular Member • Posts: 177
Re: Finding Polaris?

Easier than looking at a scale I think .

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Bill Ferris
Bill Ferris Veteran Member • Posts: 6,185
Re: Finding Polaris?

davecac wrote:

Easier than looking at a scale I think .

Oh, c'mon. If it's too easy, it's not any fun

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mermaidkiller Senior Member • Posts: 1,094
Re: Finding Polaris?
1

I also have such an electronic inclinometer, for use with mt altazimuth refractor or Dobson scope.

Latitude wedge with bubble level against a Super Polaris mount.

But for adjusting the mount I use a DIY adjustable latitude wedge with a bubble level with the Super Polaris mount. When I use that mount, I sometimes adjust using the setting circles with help of the Stellarium or Skysafari app on my smartphone.

First I setup the mount + tripod to (roughly) north.

After setting the correct polar axis elevation, I point at the zenith by adjusting the mount RA and decl circles until the telescope is vertical with bubble level, set the DE circle to my latitude and the RA circle to zero.

Then I look up a conventiently placed bright star (not too high and as close as possible to East or West) in the app and look up its declination and hour angle and then I point the scope with the setting circles to this position. Then the star is probably a few degrees out of field in horizontal direction. Then I loosen the screw of the mount on the tripod and rotate the mount (horizontally) until the star is in the field. I use a low power eyepiece with a FOV of at least 2 degrees. I tighten the screw and then I am done.
It is just a manual two star alignment where the first 'star' is actually the zenith point.

This alignment sometimes works even with two minutes unguided with 400mm (FF).

But for 400+ mm I use the polar scope, and in the South it even easier, because the +6.9 star BQ Octantis (not Sigma !) is only 10' off the pole, so I center that star in the FOV of the polar scope.

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tradesmith45 Senior Member • Posts: 2,141
Polar Alignment w/o Scope

landscaper1 wrote:

I've owned an iOptron SkyTracker Pro for some time and would like to be able to use it.

When I last made the effort (some time ago) I gave up because I found it all but impossible to locate Polaris through the optical sight in the SkyTracker. To begin with, because of light and air pollution I rarely can see Polaris even though I know the approximate area in the sky where it's located.

Does anyone have a suggestion on how to get around this obstacle? Or am I doomed to forego using a tracker anywhere other than exceptionally clear night skies?

Have 3 suggestions similar to others.  Sounds like you can find Polaris by eye but not in the finder.  The scope may have too little eye relief & too small an AOV so eye placement is critical to see anything.  Most scopes I've used are like that.

Option 1 will give plenty good alignment for 35mm & 30 sec.  Have used these in years past w/ a SkyTracker v1.0.

The compass has a declination adjustment & the big fold out lid gets the compass away from metal of the tracker.

Option 2: Place a pencil style laser pointer in the corner made by the main part of the tracker & the protrusion for the polar scope.  Been using a green pointer w/ a DIY adapter on a Nanotracker for some years.  Turn the laser on in short bursts ONLY especially in urban areas w/ LP.

Option 3: Place a cell phone w/ sky app showing polaris against the polar scope eye piece (w/o the angle finder attachment).  When polaris in the app is located in the center of the scope, your well enough aligned for 35mm.

Cheers

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82Virago Regular Member • Posts: 251
Re: Finding Polaris?

landscaper1 wrote:

I've owned an iOptron SkyTracker Pro for some time and would like to be able to use it.

When I last made the effort (some time ago) I gave up because I found it all but impossible to locate Polaris through the optical sight in the SkyTracker. To begin with, because of light and air pollution I rarely can see Polaris even though I know the approximate area in the sky where it's located.

Does anyone have a suggestion on how to get around this obstacle? Or am I doomed to forego using a tracker anywhere other than exceptionally clear night skies?

If you can see the stars of the big dipper you should see polaris.

The 2 stars that form the end of the dipper (or 'plow' ) point to polaris. If you start earlier

before it gets too dark it is the only star that the dipper stars point too.

Once it gets dark you will see extra stars in the scope and it gets more difficult.

I live in a 8/9 white zone, and can see polaris easily, once the dipper becomes apparent.

This is way before it is dark enough to observe or photograph.

If the air is so polluted you cant see polaris, picture are going to be very difficult.

One thing you can do for now, is slap on a wide lens, and just point in the general direction. Limit your shots to 10-30 seconds and you can get something.

Even semi poor first photos can be pretty exciting.  Follow some of these suggestions posted here and get back to us. We will get you shooting.  Cheers

landscaper1
OP landscaper1 Veteran Member • Posts: 4,926
Re: Finding Polaris?

82Virago wrote:

landscaper1 wrote:

I've owned an iOptron SkyTracker Pro for some time and would like to be able to use it.

When I last made the effort (some time ago) I gave up because I found it all but impossible to locate Polaris through the optical sight in the SkyTracker. To begin with, because of light and air pollution I rarely can see Polaris even though I know the approximate area in the sky where it's located.

Does anyone have a suggestion on how to get around this obstacle? Or am I doomed to forego using a tracker anywhere other than exceptionally clear night skies?

If you can see the stars of the big dipper you should see polaris.

The 2 stars that form the end of the dipper (or 'plow' ) point to polaris. If you start earlier

before it gets too dark it is the only star that the dipper stars point too.

Of all the suggestions made in this thread, the idea of attaching a laser pointer to the SkyTracker Pro (probably right above its optical sight) seems the best of all.  I'm going to try that.

Of course, my OP inquiry was based on a certain amount of optimism.  I'm 74, have high BP, and live in what is expected to be a Covid-19 epicenter (Baltimore/Washington/Northern VA region).  In all likelihood, it'll be some time before medical experts are likely to say it's safe for people like me to be getting out of our self-imposed quarantine.

Thanks to everyone for trying to help this astrophoto newbie.

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Landscaper
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landscaper1
OP landscaper1 Veteran Member • Posts: 4,926
Re: Finding Polaris?

Bill Ferris wrote:

landscaper1 wrote:

Mike,my problem is with the SkyTracker Pro's own optical (1x) sight. It has a fairly narrow field of view.

Attach a laser pointer to the mount and align it with the optical sight.

Thanks, Bill.  This strikes me as the best suggestion of all.

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Landscaper
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Alen K Senior Member • Posts: 1,141
Re: Finding Polaris?

landscaper1 wrote:

82Virago wrote:

landscaper1 wrote:

I've owned an iOptron SkyTracker Pro for some time and would like to be able to use it.

When I last made the effort (some time ago) I gave up because I found it all but impossible to locate Polaris through the optical sight in the SkyTracker. To begin with, because of light and air pollution I rarely can see Polaris even though I know the approximate area in the sky where it's located.

Does anyone have a suggestion on how to get around this obstacle? Or am I doomed to forego using a tracker anywhere other than exceptionally clear night skies?

If you can see the stars of the big dipper you should see polaris.

The 2 stars that form the end of the dipper (or 'plow' ) point to polaris. If you start earlier

before it gets too dark it is the only star that the dipper stars point too.

Of all the suggestions made in this thread, the idea of attaching a laser pointer to the SkyTracker Pro (probably right above its optical sight) seems the best of all. I'm going to try that.

Of course, my OP inquiry was based on a certain amount of optimism. I'm 74, have high BP, and live in what is expected to be a Covid-19 epicenter (Baltimore/Washington/Northern VA region). In all likelihood, it'll be some time before medical experts are likely to say it's safe for people like me to be getting out of our self-imposed quarantine.

I have seen low-power green laser pointers on Amazon for as low as $8, so it's an economical solution too. Just be mindful of airplanes and don't do it if you are anywhere near an airport.

Stay safe. We're going to get through this!

landscaper1
OP landscaper1 Veteran Member • Posts: 4,926
Re: Finding Polaris?

Alen K wrote:

landscaper1 wrote:

Of all the suggestions made in this thread, the idea of attaching a laser pointer to the SkyTracker Pro (probably right above its optical sight) seems the best of all. I'm going to try that.

Of course, my OP inquiry was based on a certain amount of optimism. I'm 74, have high BP, and live in what is expected to be a Covid-19 epicenter (Baltimore/Washington/Northern VA region). In all likelihood, it'll be some time before medical experts are likely to say it's safe for people like me to be getting out of our self-imposed quarantine.

I have seen low-power green laser pointers on Amazon for as low as $8, so it's an economical solution too. Just be mindful of airplanes and don't do it if you are anywhere near an airport.

Stay safe. We're going to get through this!

I've seen those as well.  However, I wonder if their low price also correlates to not being as bright and less able to maintain a narrow beam at greater distance.  They are, after all, intended for use in making presentations in a much smaller space.

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Allen Moss Regular Member • Posts: 229
Try the Polar Align app

Just found this on my polar align pro app. It has a daytime feature that should get you pretty close. Then you can look through the scope and fine tune. I’m going to give it a try myself.  Below is a YouTube video demonstrating the process.  Seems like the main thing to avoid is having you iPhone contact the metal as that interferes with the GPS.  I think the newer phones will be more accurate.

https://m.youtube.com/watch?t=3s&v=bq_gKvCmqBI

I’d love feedback on anyone who’s used this process!

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tradesmith45 Senior Member • Posts: 2,141
Laser Pointer "Calibration"

landscaper1 wrote:

Alen K wrote:

landscaper1 wrote:

Of all the suggestions made in this thread, the idea of attaching a laser pointer to the SkyTracker Pro (probably right above its optical sight) seems the best of all. I'm going to try that.

Of course, my OP inquiry was based on a certain amount of optimism. I'm 74, have high BP, and live in what is expected to be a Covid-19 epicenter (Baltimore/Washington/Northern VA region). In all likelihood, it'll be some time before medical experts are likely to say it's safe for people like me to be getting out of our self-imposed quarantine.

I have seen low-power green laser pointers on Amazon for as low as $8, so it's an economical solution too. Just be mindful of airplanes and don't do it if you are anywhere near an airport.

Stay safe. We're going to get through this!

I've seen those as well. However, I wonder if their low price also correlates to not being as bright and less able to maintain a narrow beam at greater distance. They are, after all, intended for use in making presentations in a much smaller space.

Landscaper, mentioned in an earlier that I use a laser pointer w/ a Nanotracker w/ success up to 135mm @ 30".  Below is a photo showing the Nano, DIY adapter (not suggesting you make one) & the pencil style pointer.  As you questioned, @ $8, these are not precision devices.  Two things to know: from my 2 copies, these do not point exactly parallel to their body so aim calibration can improve accuracy & they eat AAA barrettes pretty fast especially in cold weather.

The form factor of the iOptron makes it harder to make an adapter so I'm assuming you'll simply hold the pointer in some reliably reproducible position on the tracker which requires a face on the tracker that's parallel to the drive shaft.  (BTW, I've used this pointer in this way on a friends iOptron when we're out to help him check alignment & it worked well.)

Of course your a clever guy & may come up with another approach to using the pointer but here's my suggestions.

Be sure to get a pointer that's round & has as few protrusions as possible.  When you get one, place it on a table, point it at a wall & rotate it around its axis to see how large a circle the pointer traces out on the wall.  If it traces a large circle, you'll not be able to accurately align your tracker w/ that one because it doesn't point straight enough- get another.

Next "calibrate" your pointer.  Set up your tracker w/ polar scope (but sans angle finder & adapter) & aim at an object some distance w/ the scope reticule on some specific point.  Now place the pointer in a reproducible position against the tracker & rotate the pointer until it points to the same position as polaris on the reticule.  Mark the pointer so you can place it in that position repeatedly.  In my case, I aimed the pointer so it pointed into the center of the peep hole FOV.  For my pointer, the correct position was w/ the on button pointing down.

When pointing at polaris at night, you need to get close behind the pointer when placing the green beam on the star to avoid parallax errors.  (Sorry, no rest from getting into a low position just as w/ the polar scope-:)  When aimed at polaris, you'll be 0.5-1º off the NCP but if you use an app showing the relationship of the star & NCP, you can aim more accurately at the NCP.  But none of that is needed for short FL lenses.

FWIW, ShoeGoo can glue anything to anything.  If interested, you could use that to attach part of the pointer to the tracker - just be sure you can change the batteries.  OTOH, w/ the right parts, might be able to place the pointer in the hole for the scope.  I used simple bands to adapt my pointer to a plastic clip for polar scope on an Omegon LX3.

I too am 74 & wish you the best with you health & safety.

Cheers!

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tradesmith45 Senior Member • Posts: 2,141
Compass Calibration & Polar Align app ?

Allen Moss wrote:

Just found this on my polar align pro app. It has a daytime feature that should get you pretty close. Then you can look through the scope and fine tune. I’m going to give it a try myself. Below is a YouTube video demonstrating the process. Seems like the main thing to avoid is having you iPhone contact the metal as that interferes with the GPS. I think the newer phones will be more accurate.

https://m.youtube.com/watch?t=3s&v=bq_gKvCmqBI

I’d love feedback on anyone who’s used this process!

FWIW, this app requires a specific form factor on the tracker - i.e. a face aligned w/ the drive axis. It will work well on the iOptron the OP is using but not so well on my Vixen Ploarie.  The app daytime alignment differed by 5º from my Vixen Polariemeter ( a compass & inclinometer that goes in a hot shoe).  When possible, I'll try the app & Polariemeter against the polar scope.

I recall that some phones/tablets have a routine to calibrate the compass by rotating them several time. Haven't looked for that but something to check. The accuracy & sensitivity of inclinometer gyros is in my experience variable. Edit: turns out the app has a compass calibration mode - use it.

But as mentioned in an earlier post I have used star mapping apps in the same way & it works fine for shorter FL.

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abiquiuense
abiquiuense Senior Member • Posts: 6,505
Yes, but, love star trails; . . . (n/t)

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