Re: 2 star alignment doesn't work

Jerry Hubbell - Explore Scientific VP Engineering

Hi Harry, 

Thanks for you purchase, you are the first iEXOS 100 customer I have talked with. Generally, the 2 and 3-star alignment will improve the pointing of your scope even with the physical polar alignment off by a few degrees. It is always better to do a physical polar alignment within 1 degree of the pole, this can be accomplished by aligning on Polaris. Once that is done, a 3-star alignment is better in that it not only corrects for the misalignment between the celestial coordinate system and mount coordinate system, but also corrects for cone angle. Cone angle is the offset between your telescope and the mount. There are typically cone angle adjustments on the dovetail on the telescope. 

We are aware of a couple of problems with the iOS version of ExploreStars and are working to correct those and get the new version out on the Apple App Store as soon as we can. I will let everyone know when the updated version is available. Having said that, I am not sure why the scope would be "all over the sky" as you say. We have other customers using the iOS version with no mention of this problem. Perhaps someone that has had success with the iOS version of ExploreStars can chime in here. Unfortunately, I have not been able to test the iOS version of the app as I do not currently have an iPAD.

When you choose an object from the catalog the goal is to GOTO that object, so the primary purpose for that page is to slew to the object. You would only utilize the SYNC when you know you have the object centered in your eyepiece. You do not want to hit the SYNC button before slewing to the object because it would then tell your mount to reset the coordinates to the object when in fact you may be far off that object. Subsequent slews to objects would be way off and may be the cause of your scope being "all over the sky", I am not sure. Again, I cannot test this for myself.

I hope that answers your questions. Please review the PMC-Eight Knowledge Base on the Explore Scientific website and utilize the search tool to narrow down your topic to specific articles.

Thanks again Harry for your purchase, I look forward to hearing more about your experience with the new iEXOS 100 PMC-Eight mount and your AR102.

Clear Skies!

Jerry Hubbell
Vice President of Engineering

Explore Scientific, LLC.
jrh at
1010 S. 48th Street
Springdale, AR 72762

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

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