Topics

Polar finder scope query from a total beginner #iEXOS-100 #polaralignment


Adam
 

Hi all,

Already finding this forum a wealth of information and other owners experiences invaluable. I have a feeling the vast majority are already well aware of polar alignment and such before owning an ES mount however I am not in that club. I'm struggling somewhat with polar alignment using the official iExos polar finder scope as the subject suggests. I only have a DSLR on the mount right now as the mount became available at a time when I knew I'd be able to build-up to getting a scope eventually so I took the leap and bought it.

I have noticed that when I think I've got the mount polar aligned correctly in both the polar tunnel (central is right, right??) and the finder scope (with Polaris (I HOPE!) in the bracket between 2000 and 2030) but haven't had any lucky trying to get the 2nd and 3rd stars lined up. I'm under Bortle 6 skies here but should these other stars be perfectly visible as Polaris is? I have an app (PSAlign for iOS) to show me how to rotate the reticle on the polar finder scope so I'm pretty sure I have that bit right.

On to my next question though, which may be related to the first...when I think I have the mount aligned and I check the latitude it's around 49 degrees instead of the 51.05 that I'm actually viewing from. Does that make any sense?

Sorry to sound as foolish as I think I'm sounding. I will absolutely appreciate any guidance anyone can give me. Sending links to anyone else who has set this mount up and can show me exactly how it's meant to be done would be great with a little explanation of what I'm meant to be memorising :-)

All the best to you all,

Adam


 

Could be one or two reasons, first thing I would do is check that your polar scope is properly collimated, there are plenty of tuition material on line that will help you with this. Secondly even if you have collimated the scope and polar aligned there will still be a bit of adjustment to get the star central. Even when I think I have a good polar align it can still be a bit off. The more you do it the better you will be. My next stop is the Polemaster for me, just to get a more accurate polar alignment. 
--
Michael Whitaker
Wakefield, UK. 
MOUNTS. Exos-2 PMC Eight..
SCOPE: RVO Horizon 72ed. 
CAMERA: Not Applicable. 
SOFTWARE: Just iPad at moment.


Adam
 

Thanks Michael for the speedy response. I'll double check the collimation as soon as possible. If I'm doing it right (which I may not be!) I'm centering the "target", a church spire over a mile away, in the polar tunnel, then using the collimating screws to get the target on the central point of the finder scope. OR should I be trying to get the spire to sit where Polaris should be? I'm going to keep Googling furiously.

The latitude setting still doesn't make any sense to me as when I have Polaris aligned I'm nearly 2 degrees lower at 49 and not 51 degrees. 


Wes Mcdonald
 

To get collimated get the dead center of the polar scope on the dead center of the ra axis.  You have to do this by rotating the ra axis and adjusting so that the dead center of the polar scope never drifts off the target in the polar scope. Remember you are aligning the polar scope with the ra axis of rotation not the telescope which has its own ra axis collimation issues.

--
Wes, Southport NC
EXos2-GT PMC-8, iExos 100
ES ED 127, 10" LX200GPS+wedge, Astro-Tech 8" Newt, ETX-90, 60mm no-name guide scope ~ 260mm FL
Polemaster, Orion ST-80 and SAG, ZWO 290MM, D5300 astro modified
Nina, Bootcamped Mac Mini control computer, RDP to iMAC
110 amp hour lead acid deep discharge battery for field power
Electrical Engineer, Retired


Wes Mcdonald
 

Adam. Ok iexos 100. Sorry

The peep hole is fine but it will be a poor polar aligner.  You may as well just center Polaris in the tunnel. That is fine enough for visual work IF you have a wide field finder scope.

What you are trying to collimate is your main telescope line of scope and your finder line of sight.  This is true of any finder scope.  Your peep hole is already collimated with your ra axis.

To do a 2-3 star alignment most easily you need to have your polar home pretty close.  Use my paper in the files section of the mounts subgroup.  

Get yourself a red dot finder.  It is far easier to identify the alignment star when you can view it through the red dot and see all the other surrounding stars.

Make sure you align the scope on the correct alignment star.  Use something like SkySafari to identify unambiguously the correct star you are supposed to use.

As for your latitude and lon suggest you use your tablet gps fix and set explorestars to use the tablet location. Save you from entering.  If it still comes up “wrong” then either the tablet didn’t get a fix or your idea of what right is wrong?  Can’t explain it any other way.

Final thing is for your gotos to be good after you do a 3 star alignment the mount dec polar home is paramount.  Second is cone angle.  Third is correct star centering.  PA is not that critical for 3 star as 3 star’s purpose is to correct for incorrect PA.  If you mark the Polar home using my method then it is important to ensure that when you set up to use the scope it is as level as it was when you marked the home location.

Wes 



--
Wes, Southport NC
EXos2-GT PMC-8, iExos 100
ES ED 127, 10" LX200GPS+wedge, Astro-Tech 8" Newt, ETX-90, 60mm no-name guide scope ~ 260mm FL
Polemaster, Orion ST-80 and SAG, ZWO 290MM, D5300 astro modified
Nina, Bootcamped Mac Mini control computer, RDP to iMAC
110 amp hour lead acid deep discharge battery for field power
Electrical Engineer, Retired


Jed Fish
 

Hello, Adam , 
Re:  the latitude setting - if you’re referring to the scale printed on the mount, take it with a grain of salt, it’s just to get you close.  

I’m at just under 41 degrees and mine generally reads ~39 with Polaris anywhere in the tunnel. I’m strictly visual, so the tunnel (no polar scope...)  is close enough for me.  Others will respond with more accurate technical solutions that will get you centered on the North Celestial Pole, necessary for photography, but for now if the mount is level (at least on the north south axis) and Polaris is in the tunnel, that’s your latitude setting.

Even if the printed scale was perfectly precise, it could read much as 2/3 of a degree off (above or below the scale set to your exact latitude) if you were centered on Polaris instead of NCP.  

HTH, 


--
Jed Fish
ES ED102
iExos100


Adam
 

Thanks Wes and Jed.

Wes, could you direct me to a suitable red dot finder? I'm currently just imaging with my DSLR as I've not managed to gather the funds for a scope and large finder scope for auto-guiding as of yet. All the red dot scopes I've found so far this evening fit directly onto telescopes I don't have :-/ Thanks for the heads up about your paper, I shall get to reading :-)

Jed I'm glad to hear I'm not going mad then. As I was pretty convinced I had Polaris dead in my sights it was concerning to find myself roughly 2 degrees off on latitude each time.


jrichard333 <jrichard333@hotmail.com>
 

Good day all,

 

It does not hurt to ponder the mysteries of the universe.  I am a big believer of not reading manuals and believe all things should be intuitive; however, when normal logic evades me (yeah….keep running logic, I am closing in), I consult the manual.  iEXOS-100 pg. 12 pertains to backlash in the altitude knob which can vary between 1 to 1.5-degress due to the tangent arm design.

 

Have fun…first shot at clear skies in 1.5-weeks (well, we are being threatened by hurricanes)…we shall see in the upcoming hours.  In c losing, just go away rain, I don’t want to play…. ever!!!!

 

JR

 

From: MAIN@ESPMC-Eight.groups.io [mailto:MAIN@ESPMC-Eight.groups.io] On Behalf Of Adam
Sent: Sunday, August 2, 2020 6:24 PM
To: MAIN@ESPMC-Eight.groups.io
Subject: Re: [ESPMC-Eight] Polar finder scope query from a total beginner #polaralignment #iEXOS-100

 

Thanks Wes and Jed.

Wes, could you direct me to a suitable red dot finder? I'm currently just imaging with my DSLR as I've not managed to gather the funds for a scope and large finder scope for auto-guiding as of yet. All the red dot scopes I've found so far this evening fit directly onto telescopes I don't have :-/ Thanks for the heads up about your paper, I shall get to reading :-)

Jed I'm glad to hear I'm not going mad then. As I was pretty convinced I had Polaris dead in my sights it was concerning to find myself roughly 2 degrees off on latitude each time.


Wes Mcdonald
 

Adam

Ugh

For a camera only rig I guess I would find me a hot shoe adapter.  If we target a red dot with a synta mount then you could use this:


Then you could get a red dot such as this which would fit Into the bracket;


Now these two accessories add up.  But they would work. And the red dot would be useful in the future when you get a scope.  Not so much the hot shoe.

You can probably find a cheap red dot finder on cloudy nights classified.  Maybe a mount too.  But you can also mount a red dot with double sided tape or an elastic band if you can figure out where on your camera body.

The quality of the red dot almost does not matter.  Your problem really is how to attach it to your camera body.

The red dot need not be on the camera body but I don’t think you have any other place to put it that will stay aligned with the camera fov

It occurs to me one other thing about getting a 2-3 star with a camera lens.  You need to be careful to put that star in the dead center of the lens fov.  Difficult if low power and with no crosshair.  To the extent you don’t center the star your alignment will be affected negatively.

Wes



--
Wes, Southport NC
EXos2-GT PMC-8, iExos 100
ES ED 127, 10" LX200GPS+wedge, Astro-Tech 8" Newt, ETX-90, 60mm no-name guide scope ~ 260mm FL
Polemaster, Orion ST-80 and SAG, ZWO 290MM, D5300 astro modified
Nina, Bootcamped Mac Mini control computer, RDP to iMAC
110 amp hour lead acid deep discharge battery for field power
Electrical Engineer, Retired


Harry
 

I have found the Rigel Quickfinder easy to install, adaptable, and affordable. I use it with a DSLR and seperatly  a 80mm  scope.
Harry

On Aug 2, 2020, at 8:01 PM, jrichard333 <jrichard333@...> <jrichard333@...> wrote:



Good day all,

 

It does not hurt to ponder the mysteries of the universe.  I am a big believer of not reading manuals and believe all things should be intuitive; however, when normal logic evades me (yeah….keep running logic, I am closing in), I consult the manual.  iEXOS-100 pg. 12 pertains to backlash in the altitude knob which can vary between 1 to 1.5-degress due to the tangent arm design.

 

Have fun…first shot at clear skies in 1.5-weeks (well, we are being threatened by hurricanes)…we shall see in the upcoming hours.  In c losing, just go away rain, I don’t want to play…. ever!!!!

 

JR

 

From: MAIN@ESPMC-Eight.groups.io [mailto:MAIN@ESPMC-Eight.groups.io] On Behalf Of Adam
Sent: Sunday, August 2, 2020 6:24 PM
To: MAIN@ESPMC-Eight.groups.io
Subject: Re: [ESPMC-Eight] Polar finder scope query from a total beginner #polaralignment #iEXOS-100

 

Thanks Wes and Jed.

Wes, could you direct me to a suitable red dot finder? I'm currently just imaging with my DSLR as I've not managed to gather the funds for a scope and large finder scope for auto-guiding as of yet. All the red dot scopes I've found so far this evening fit directly onto telescopes I don't have :-/ Thanks for the heads up about your paper, I shall get to reading :-)

Jed I'm glad to hear I'm not going mad then. As I was pretty convinced I had Polaris dead in my sights it was concerning to find myself roughly 2 degrees off on latitude each time.


--
Harry
Vero Beach, FL
Scopes: ES  ED80CF, ES AR102,  Meade ETX 90 EC (Deforked)
Mounts: ES iExos 100-PMC Eight, ExploreStars IPAD & Fire HD8
Nikon D600, D5500, MacOS, Starry Sky Stacker, Lightroom, Affinity Photo


Adam
 

Thanks for the links and advice Wes. The DSLR-only setup is temporary as I’m looking at the 130PDS as that seems to be everyone’s go-to (pun intended 😊) as a good place to start for imaging.

I’ll look into getting a red dot finder where I can adapt it for the camera/scope in future I think as mounting it on the imaging unit be that to camera or a scope makes sense.

Thanks Harry for the Rigel recommendation. I’ll start there 😊


brian skinner
 

Hi Adam, your set up is the same as mine. I have just, I think, mastered the Polar Scope, here is my modus operandi;

1. Remove camera to help ease of viewing through the PS

2. Make sure your mount is and stays level

3. You must Collimate the PS, its tricky and patience is required for sure, but if I managed it....

4. Adjust the mount so that it is pointing roughly towards Polaris/North

5. Using the latitude adjuster, adjust the PS such that that its reticle is at or around the same latitude as either Ursa Major OR Cass, depending on which is most visible/ convenient.

6. By eye, rotate the PS reticle in its mounting bracket until the constellation of your choice angularly aligns with the actual constellation. This takes a little time but obviously this needs to be as accurate as possible, again, if I can do it....

7. When 6 is achieved move the mount physically and gently, until you see Polaris in the PS.

8. Using the latitude adjuster and physically left to right mount adjustment, place Polaris in the little gap in the PS Polaris line. When that is achieved you have a good Polar Alignment, I am managing 3 minute exposures without major trailing.

9. Power up the mount, set up the WIFI and you are good to proceed to alignment.

Regarding finding your alignment stars you first need to ensure your camera is focused well, and certainly I would also recommend a red dot finder, I have one which fits the camera hot shew bracket. Don't forget, the longer your focal length, the narrower the field of view so, it is possible your alignment stars will be outside your live view image, a red dot finder will allow you to home in gently using the ES App UDLR buttons.

Hope this helps you, kind regards, Brian


--
Brian Skinner
iEXOS100
Canon 1300d dslr
Various lenses
ES Polar scope
Sequator image stacker
PIXR image editor