Topics

Polar alignment problems. Picking new alignment group? #ExploreStars

 
Edited

Due to the location of my backyard I can barely see Polaris and the rest of the Alignment Group 6. Is there a way to align using other stars? Such as Rigel? I can only see group 6 under my 2 or 3 star alignments. My house and the neighbors block that portion of the sky but if I move to see them, I can only use the sky that is illuminated by street lights. 

First time using the mount and I was able to get pretty tight stars at 30 sec, so that's working well! I still suuuuuuck at slewing manually to find anything. Took me forever just to center a single star.

Chris Tardif
 

Hey Burks....I'm not sure what your rig is so I will generalize a bit...

If you are using a scope and not a camera lens then I found using an eyepiece to star align really helpful, but software can help.

I use a PC, Windows and ASCOM so I use SharpCap for polar align (which can do a drift align so you don't need polaris) and I use All Sky Plate Solver to center images.  With this set up you can get away with some error in you PA depending on how short or long the focal length you're using its.  

Make sure its dead level and use a compass to point it north before you put the mount on. That will get you 90% of PA then you should be able to get the rest with software.

HTH....

Chris



--
Mounts: Explore Scientific IEXOS-100 w Celestron CG5 tripod, iOptron CEM 40
Scopes: Explore Scientific FCD-100 ED-102CF, Various Canon lenses, ZWO mini-guidescope, StarField 60mm guide-scope.
CameraASI120MM Mini (mono), Altair GPCAM 130
Control PC: Intel NUC
Loc: 44 -79

W.F.
 

Hello Burks,
when you start the alignment, the sytem shows you a star and moves the teleskop on it.
If you now go to the main menu ---> catalog, it shows you stars for alignment.
There you can select the star you like to use or you can see.
Click at the Icon an then "slew to the target", in the main screen you can see the star is now in your alignment.
Now follow the steps as usual.
Greetings Wolfgang.

 

I'm sorry Chris, I bet that info would be helpful. It's an iexos-100 mount and I'm using the Explorestars app on my laptop. 

Wes Mcdonald
 

Burks21

What tablet?  Each version works a bit differently during alignment

Wes

--
Wes, Southport NC
PMC-8, ES ED 127, 10" LX200GPS, Astro-Tech 8" Newt, ETX-90
Polemaster, Orion ST-80 and SAG
Electrical Engineer, Retired

 

Wes, 

Not using a tablet. Sadly my wife's Kindle Fire and ipad 2 are too old. So I'm stuck with my laptop. 

W.F.,

Problem is the group assigned to my alignment really arent useful for me due to houses blocking that part of the sky. I basically can see from the direct north (barely) to the south. Anything west is a no go. 

Wes Mcdonald
 

Burks

The windows explorestars could use a facelift.  I suggest you get an Android based system.  Its alignment routine allows you to select stars from the catalog.  This is a capability peculiar to the Android version.  It also gives you the ability to select a star prior to slewing to it.  This saves time and circumvents a minor issue that can lead to the mount moving very slowly during a slew.

You can get an inexpensive Samsung tab A which I and others have had.   The fire hd also seems to work.  Don't go Chromebook however.

You can also use an iterative method for polar alignment as detailed in a paper Jerry posted.  The routine calls for using Polaris and one other star but I believe you can use any other star instead.  This is a method that can get you both polar aligned and get your ra and Dec home positions correct so that further gotos will work.  If you do this, you have no need for the 2 or 3 star alignment.

In my view it is impossible to perform the 2 or 3 star alignment without a red Dot finder.  Get one. It's about the only way you can decide which star is the proper alignment star.  I also use SkySafari to identify the exact star in the star field which I then center in the red Dot and then in the eyepiece.  

When you do the centering you must get it very close to eyepiece center.  Error in centering will be reflected in the alignment solution and make your gotos worse.

Finally it is very important to get your ra and Dec home positions correct.  I posted a procedure and discussion document in the files section of main or mounts subgroup.  Use the second section for astro photography as it is the only way to get those home positions... Short of using cameras.

Wes

--
Wes, Southport NC
PMC-8, ES ED 127, 10" LX200GPS, Astro-Tech 8" Newt, ETX-90
Polemaster, Orion ST-80 and SAG
Electrical Engineer, Retired

Chris Tardif
 

If you're using a laptop then I go back to my first post.  Free software can save you.  AstroPhotographyTool (APT), All Sky Play Solver and SharpCap.


--
Mounts: Explore Scientific IEXOS-100 w Celestron CG5 tripod, iOptron CEM 40
Scopes: Explore Scientific FCD-100 ED-102CF, Various Canon lenses, ZWO mini-guidescope, StarField 60mm guide-scope.
CameraASI120MM Mini (mono), Altair GPCAM 130
Control PC: Intel NUC
Loc: 44 -79

 
Edited

Chris,

I am using a laptop for right now, but I have downloaded APT just to try it out anyways. I'll be getting an Amazon Fire 8HD during the black Friday sales.

Wes,

I'm hoping with the combo of APT, a compass, and some better knowledge I will be able to get a better polar alignment. I am also waiting on black Friday sales to maybe pickup a guide scope and adapt my webcam (I've used it to take some pretty decent video of the moon) so that I can use that to help guide/alignment issues. I might grab one of those illuminated crosshair eyepieces if I continue to have trouble, but I'll wait as those seem to have only one job and one job only. I wouldn't mind being able to polar align and guide with the same setup. Maybe, if they are on sale, I might even grab a 120MM camera to use as a guide camera (or even imaging?) as well. Who knows. Just got a really nice bonus from work so....that helps!

Jeff Snell
 

Folks,
I had some issues in the past with the polar alignment but after some research and a little luck, I discovered the "Polar Scope Align" app I was using has the exact same depiction in it's data base that the alignment scope on the EXOS2 GT uses.  It is buried in the settings menu under "Change Polar Scope Reticle."  I now exclusive use that presentation and while I still have some fine tuning to do, my targets are consistently in view after slewing and stay relatively stable through at least two minute exposures...very minimal star elongation.  For me, the discovery was momentous and rather than being frustrated, I'm just cold (Northern Utah observing).

On a separate subject, I want to start using my Orion Guide Scope setup but am a bit perplexed on the cabling and connection to PHD.  I saw a video by Dillon O'Donnell where he insisted the cabling should go from camera to computer then computer through PHD to mount for the tracking.  The supplied cable appears to be an RJ-11.  I need a cable with and RJ-11 on one end and a USB on the other to connect direct from computer to the PMC-Eight.  Is there such an animal and more importantly, am I thinking correctly on how to set up the connection sequence?

Thanks,
Jeff

Scope: ES ED80 APO/Celestron 8" Edge HD
Mount: EXOSGT 2 w/PMC-Eight
DSLR: Modified Canon T-5i

    

On Tue, Nov 12, 2019 at 8:29 PM Burks21 <nygburks2121@...> wrote:

[Edited Message Follows]

Chris,

I am using a laptop for right now, but I have downloaded APT just to try it out anyways. I'll be getting an Amazon Fire 8HD during the black Friday sales.

Wes,

I'm hoping with the combo of APT, a compass, and some better knowledge I will be able to get a better polar alignment. I am also waiting on black Friday sales to maybe pickup a guide scope and adapt my webcam (I've used it to take some pretty decent video of the moon) so that I can use that to help guide/alignment issues. I might grab one of those illuminated crosshair eyepieces if I continue to have trouble, but I'll wait as those seem to have only one job and one job only. I wouldn't mind being able to polar align and guide with the same setup. Maybe, if they are on sale, I might even grab a 120MM camera to use as a guide camera (or even imaging?) as well. Who knows. Just got a really nice bonus from work so....that helps!

Kent Marts Explore Scientific Customer Service
 

I went to the Explore Scientific reticle, but it's not the correct one.

The correct one is Skywatcher/Celestron/Meade.

Great find, Jeff.

Kent Marts
Customer Service
Explore Scientific

Wes Mcdonald
 

Jeff

Relative to wiring if the PHD.

1.  Camera USB to computer.  Into PhD.

2a.  If ascom...PhD send guide commands via ascom driver to PMC8 via computer connection to PMC8

2b.  If not ascom....tell PhD the guiding is via camera.  Then connect the RJ11 between the camera guide port and the PMC8 guide port input.

Wes


--
Wes, Southport NC
PMC-8, ES ED 127, 10" LX200GPS, Astro-Tech 8" Newt, ETX-90
Polemaster, Orion ST-80 and SAG
Electrical Engineer, Retired

Jerry Hubbell - Explore Scientific VP Engineering
 

Hi Jeff,

Wes is correct in that you have 2 choices. I always tell customers that it is better to just use one cable versus two and use the ASCOM driver connection with pulse-guiding on PHD2. There are extra features in that PHD2 with the ASCOM connection knows what your mounts current Declination is so it can compensate accordingly.
--
Jerry Hubbell
Vice President of Engineering

Explore Scientific, LLC.
jrh at explorescientific.com

www.explorescientificusa.com
1010 S. 48th Street
Springdale, AR 72762
1-866-252-3811

Author: Scientific Astrophotography: How Amateurs Can Generate and Use Professional Imaging Data
             Remote Observatories for Amateur Astronomers: Using High-Powered Telescopes From Home


Mark Slade Remote Observatory (MSRO) IAU MPC W54 Equipment
Wilderness, VA
Mounts
: ES PMC-Eight G11 + Telescope Drive Master (TDM)
Scopes: ES 165 FPL-53 ED APO CF, ES 102 FCD100 ED APO CF
Cameras:  QHY174M-GPS + FW, QHY163C
Misc: 3-inch 0.7x Focal Reducer Field Flattener, Filters: Luminance,
Red, V-band Photometric, Diffuser, 200 lpmm Spectral Grating

Software: MaxIm DL 6, Cartes du Ciel, Astrometrica, AstroImageJ, AutoStakkert!

Jeff Snell
 

Thanks gentlemen!

Jeff

On Tue, Nov 19, 2019 at 8:07 AM Wes Mcdonald <wesmcd6@...> wrote:
Jeff

Relative to wiring if the PHD.

1.  Camera USB to computer.  Into PhD.

2a.  If ascom...PhD send guide commands via ascom driver to PMC8 via computer connection to PMC8

2b.  If not ascom....tell PhD the guiding is via camera.  Then connect the RJ11 between the camera guide port and the PMC8 guide port input.

Wes


--
Wes, Southport NC
PMC-8, ES ED 127, 10" LX200GPS, Astro-Tech 8" Newt, ETX-90
Polemaster, Orion ST-80 and SAG
Electrical Engineer, Retired