Celestron Celestar 8 mount (wedge?)

sharptrack2 (Kevin) · #1 06-12-2015, 07:17 PM

Hello,

I have been struggling with aligning this specific scope/mount combination for a few weeks now (photo attached). I have read every thread that even remotely mentioned this combination and how to align. The instructions are all straight forward and easily understood and performed, but.... the scope will not track an object. I have confirmed that the motor drive is working and working correctly, it turns in the right direction when instructed to.

There are two things I would like to confirm. The first is that the "RA" tracking will not actually work as it does with a GEM mount since it actually cannot form an arc when moving. I have noted that I constantly have to adjust the DEC arm to keep the object in view. I have reasoned that since the RA circle is actually on a declination plane and doesn't "rotate" on the polar axis, it can't possibly follow an object like a GEM mount. I'm happy to be told I'm wrong but the evidence is overwhelming in my opinion.

The second thing I would like to confirm is the coarse DEC adjustment. I have read that it should be set to the latitude of the observing location. All well and good, but I have also read that a wedge style mount should actually be set to the compliment of the latitude. Which is correct? My reasoning tells me that it should in fact be the compliment angle, and my very unscientific investigation with the scope the other night also suggests this, but it got cloudier as I tried to work it out and my target stars kept disappearing.

Will be out tonight with binoculars and scope... hopefully I will come back with both still in good shape.

sharptrack2 (Kevin) · #2 07-12-2015, 12:01 AM

I either did something wrong and don't know it or did something different and don't realise it.

Tonight went exceptionally well considering. In between little fluffies floating by, I verified my polar alignment. The wedge angle setting is correct using the location's latitude. I'll take that on the chin.

I could have previously been off on compass setting but I don't think so. I have my compass dial set 12 degrees east, so that when I have the needle lined up with North, I should be pointed 12 degrees west. Another possibility is that in the past I have pointed the reference leg south as it would normally be for a GEM, but tonight I went with north. Regardless, the mount tracked reasonably well. I suspect there may still be a speed problem but that will have to wait until I have a few hours to break the RA drive down, clean it, and re-lube it, to make sure it isn't just sticky and slow.

So I have proven that all the experts are right and my brain is on vacation somewhere. I suppose practice will make perfect eventually. 47 TUC was quite a sight tonight, it was my first time seeing it through the telescope.

louie_the_fly (Stew) · #3 08-12-2015, 08:49 PM

Before I changed to a HEQ5PRO my Celestar 8 mount started intermittently playing up. It wouldn't track properly all of a sudden. then it was OK, Then problems again. It turned out that the setting circle clutch had tightened up and was making the drive slip. I pulled it apart, lightly lubed it, put it back together, and it worked OK again. Do you have the manual? If not, you can downloaded it off the web.

sharptrack2 (Kevin) · #4 08-12-2015, 09:40 PM

Thanks Stewart,

I'm thinking that that might be my next step if I continue to have trouble.

Yes the original manual came with the telescope. I have read it a couple of times now. I also found a Yahoo User group just for Celestron Celestars and C8's (I think they are the same thing but people keep make the distinction).

Waiting for the weather to clear....