psismondi
(newbie)
06/16/09 10:38 AM
ETX-90 RA Mount Question from Newbie

I hope I will be forgiven for asking this question, since it is so basic. However, I am doing this on behalf of my father, who is the owner of the ETX-90 RA (no electronics, motor only).

Dad got this telescope ten years ago. My brother-in-law is an amateur astronomer, and he selected it for Dad. However, the telescope has never been used. It was damaged (excessive heat) in shipping or something, and then ignored until this spring. Dad asked me to have Meade repair it so he could use it. I did this, and recently got the ETX-90 back in like new condition. I am visiting my parent for two weeks, so I have little time to help Dad get going with the ETX-90.

I know little or nothing about astronomy, but I want to help Dad look at the moon and Saturn - he is passionately interested in those two objects.

I did the view finder alignment business with no trouble. I also did the polar alignment as I understood it from the manual. But....

It seems that when polar aligned such a telescope should be angled up in the mount to its maximum position. (I don't know the terminology too well). That is, with the eyepiece thingy up, the tube is parallel to the back leg (with the latitude on it), and that is as far up (away from the horizon) as it is permitted to go in the mount. In this orientation the telescope is pointing right at Polaris.

So then how would one look at something immediately ABOVE Polaris (in angle) and near to Polaris if the telescope cannot be angled any further up? I don't get it.

Once again, I know this is so basic that the answer is certainly to be found in a basic book. Please overlook this as I am trying to help a 77 year old non-technical retired person get going on this before I depart for my own home town.


JT5
(professor emeritus)
06/16/09 10:59 AM
Re: ETX-90 RA Mount Question from Newbie

There is a discussion of both polar and Azimuth-Elevation alignment methods. Unless you are doing Astrophotography the AZ-EL method is easier to do and understand. There are lots of photos that will assist you. The organization of material is somewhat unorganized. It is best if you read through the manual cover to cover there is a lot of key information toward the back of the manual for my ETX-125PE.

Is there a handheld control pad that lets you slew up-down and left-right? Check the manual and locate the battery location for the scope. If it is anything like my -125PE they are under a cover on the bottom of the scope. They should not be left in the scope more than a couple of weeks or as they go bad they leak a corrosive gunk that is bad for the insides of the scope.

John


Joe Lalumia
(Post Laureate)
06/16/09 11:25 AM
Re: ETX-90 RA Mount Question from Newbie

Have dad print off and read these links--

http://www.weasner.com/etx/ref_guides/polar_align.html

http://www.meade.com/manuals/etx/index.html


psismondi
(newbie)
06/16/09 11:47 AM
Re: ETX-90 RA Mount Question from Newbie

Thanks folks. I read the material at the urls posted by Joe Lalumia.

I think I can do that actual polar alignment. Assuming I have done so - I still cannot look at something just above the north celestial pole with the ETX-90, right?



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