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CGE Newby help

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#1 Mitchell Duke

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Posted 27 January 2011 - 11:27 PM

I have had my CGE for about a year now, and I use it for imaging the planets. I decided I was tired of trying to keep the planets on the CCD, and now im trying to get the scope polar aligned. My problem is when I slew to the first star on the alignment it is no where in site. Im looking for some advice on what I might be doing wrong in the process. I lined the mount axis with polaris, but I did not use the finder scope. Should I use the finder scope to center polaris. Thanks ahead for the help on this situation :)

#2 zawijava

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Posted 27 January 2011 - 11:35 PM

You need to make certain that your scope and the finderscope are aligned ie pointing at the same object. It sounds like they are not aligned from what you described.

Tim

I have had my CGE for about a year now, and I use it for imaging the planets. I decided I was tired of trying to keep the planets on the CCD, and now im trying to get the scope polar aligned. My problem is when I slew to the first star on the alignment it is no where in site. Im looking for some advice on what I might be doing wrong in the process. I lined the mount axis with polaris, but I did not use the finder scope. Should I use the finder scope to center polaris. Thanks ahead for the help on this situation :)



#3 Mitchell Duke

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Posted 28 January 2011 - 12:19 AM

The finder, and scope are both aligned on the same object. The question is can the finder scope be used to center Polaris to rough align the mount?

#4 ShawnPreston

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Posted 28 January 2011 - 02:12 AM

Very roughly, yes. You'll still need to do the 2 + 4 alignment though to get things close. Don't worry if you first couple of stars it takes you to are way off, by the time you finish the 6 stars, you should be about right on.

Shawn

#5 drksky

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Posted 28 January 2011 - 10:12 AM

Do a 2 + 4 star GoTo alignment before starting the ASPS routine.

Make sure your date, time and location are accurately set.

#6 Eddgie

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Posted 28 January 2011 - 10:26 AM

Unless you are using an AutoGuider, then putting polaris in the center of the finder will not solve your problem, and doing calibration stars won't necessarly solve the problem either.

If the problem is that your target is drifting off of the chip, then you MUST do a true polar alignment.

The CGE does not track in Declination. It only tracks in RA. An Autoguider can send signals to the DEC motor, but the mount itself does not do anything to adjust for tracking drift.

So, if you are imaging, you need to do an ACCURATE polar alignment, or get an autoguider.

The issue with missing your first alignment star can have several possible causes. Even if you are accurately polar aligned, there is usuallly a little slop in the scope, but there is almost always some cone error as well.

The Calibaration Stars are there to cancel out the cone error, but the mechanical play still means that it is difficult to get the mount to always hit the first star in the finder.

If I set up using a star chart to approximate the position of the NCP and point the Telrad so that Polaris is at the right "Clock" postion for time and date, my first alignment star will almost always fall within the Telrad 4 degree circle.

So, to prevent DEC drift, you have to accuratly polar align to the NCP and not Polaris, or get an autoguider.

Polar aligning is still recommended, but with the guider, it doesn't have to be as exact.

#7 David Pavlich

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Posted 28 January 2011 - 11:59 AM

It's not unusual to have the first star fairly far out of the FOV. Make sure that the first star you choose is a bright star that stands out from the background stars and that it's positively identified. Before I built my obs, I had a Telrad and a 9X50 finder scope to make set up easier. With the Telrad, it's easy to get the first star in the center of the bullseye because regardless of how far out of the FOV the star is, it's easy to find with the Telrad. From there, it's easy to refine the alignment.

After the first star is centered, the second star will be much closer. Of course, this is all predicated on the assumption that all of the information entered is correct.

David

#8 pgrunwald

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Posted 30 January 2011 - 09:25 PM

I have had my CGE for a couple of years. This is my routine:

1) If you have not done so, do a factory reset on the hand controller. Set up lat and long and MOST IMPORTANT - set the time and make sure the daylight savings time is set correctly!
2) Make sure you have the latest firmware on the hand controller and motor control board. The versions of the uploader are not the same as the firmware versions. If you do not have a programmable hand controller, consider getting one as the new firmware is well worth it. I bought a used one and sold my original, the upgrade cost me $50 net and is well worth it.
3) When I set up, I point my tripod leg north. You can do this with a compass or the north star but figure out your local delineation and adjust. The closer you are, the more adjustment range you will have with the head.
4) Level the tripod before you mount the electronics pier and mount. DO NOT EVEN TRY TO LEVEL WITH THE SCOPE ATTACHED! I have a little level that I got from Lowes as my bubble on the head is not that accurate.
5) After I mount the scope and balance (don't forget!!!), I adjust the head through a telrad on Polaris adjusted a little for declination.
6) I do a two star and at least two calibration stars.

When I do this, my goto's are very accurate on both sides of the meridian.

HTH,
Paul

#9 Mitchell Duke

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Posted 30 January 2011 - 10:29 PM

Thanks everyone for the help, I solved all of my issues. The first thing I did was while aligning each star the scope slewed to I googled it to find a map of it's locating. This worked great, and all of the stars were in the FOV after the first star. I completed the all star polar align, and Jupiter did not move for a good 10 minutes. I marked all of the mounts movable parts, the concrete, and even the bubble level so that this polar align will last. This will have me imaging alot quicker with improved results...






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