CG5-GT Alignment

[Mark in Macc]

I'm currently considering the CG5-GT mount as a package bought with a C8 SCT. I've only ever owned an Alt/Az mount before and just wanted some advice on alignment. Is it absolutely necessary to polar-align to get decent accuracy? There must be some occasions when you can't see Polaris? I'm not currently thinking of doing any imaging, just visual observing. I'm fairly technically minded, so I'm not put off by an equatorial mount, just inexperienced.

[malc-c]

Provided the alignment is more or less correct you'll get decent goto's - but having it aligned accurately helps, and if you are going to venture into imaging, then it's a must. There are other ways to polar align if you can't see Polaris

[Tzetze]

I use the CG5-GT. For visual, you will only need to do a rough polar alignment. Simply sighting polaris through the hole in the mount where the polar finder scope accessory fits will do. You then step through the goto calibration procedure (10-15 minutes) and you should have decent accuracy for visual observing.

[MarkSix]

You can do a rough polar-alignment just by setting the latitude and pointing the mount north with the aid of a compass and do a 2 star aligment. Then there is the All-Star polar alignment routine that you can use if you need better accuracy. It's a software routine where you align the mount with the mounts alt/azm adjusters.

[James4]

Marc, I've not looked through the polar scope in over a year - rough alignment works fine! The CG5 is a solid workhorse for the money.

[Uranium235]

Procedure for PA with CG5-GT:

1) First, calibrate your mount with two alignment stars and three calibration stars.

2) Slew to a named star which is near(ish) to the southern end of the meridian (either side), and no more than 20deg above or below the celestial equator (use stellarium) - this will give you the best possible alignment.

3) Run through the polar alignment routine in the handset (under align menu), follow it to the letter.

4) Thats it, youre done!

I read in the nexstar update history that re-calibration is now not required after polar alignment - unless your PA was a million miles off, in which case a tweak of the calibration might be required for pointing accuracy. In addition, theres also no harm in repeating steps 2 and 3 again to improve the alignment even further.

Hope that helps.

[Explorer 190 MN]

I normally go through calibration procedure and polar align 2 to 3 times but I image. I had a 8" Newtonian with guide camera and DSRL on it and got 10min subs in test runs. Here is what I do.

1.Set up tripod point roughly north.

2.Install head look set latitude scale, look through polar alignment hole for Polaris. If polaris is hard to see then look with one eye trough the hole and the other eye on Polaris

3. Counter weights

4.Optical Tube Assembly (OTA)

5.All star calibration/alignment (see manual which you can download now from celestron)

6.Polar alignment procedure on the Hand Control

After you have done this a few times you will be able to eyeball the celestial pol quite well. It is frustrating and confusing in the beginning!! Relax!! have a coffee and try again. The stars have been around since the beginning of our time and will be there until the end of our time. Make sure you read the manual and get the balance correct maybe even buy a double cross hair ocular to help with alignment it will improve your goto´s and Celestial pol alignment. Because of slack in the gearbox you need to make your final adjustments in alignment using the right direction button and the up direction button this will also give you more accuracy in calibration/alignment. If you don´t rush and do the proper foot work at the beginning of the session you will have a much better night out. If you are having problems just ask I rebuilt my mount to get it as good as I could for what it is. I have had a great time with mine with no trouble apart from user error!! I never found any rough finish on gears or bad grease inside mine I did discover that my Advanced Series CG5GT did not have the promised bearings inside it !!!! as advertised !! I did max the mount with a Astrograph and all extras and it tracked very well if fact I had less problems with my CG5 than my new CGEM.

[arbacia]

With a CG5-GT do not neet to have the norther sky at sing at all. Polar aligng is done with no view of the polar star. Moreovr you don't need to have a polar finder installed.

The Nexstar hand control by pass the usual polar alignment in which the polar finder is placed in the spot of reticle of the polar finder touching the azimut and elevation screws of the mount prior to alignment.

Recent firmware versions of Nexstar allow about 14-16 degrees of azimut and elevation error in the orientation of AR axis toward the celestial pole.

Just place the mount pointind broadly toward the Pole. Set time and coordinates. and use a two stars alignment (much better if use another 4 additional callibration stars, usualli this is called a 2+6 alignment). For visual use is enough.

However is better is you do a polar alignment. Which is do it later. During the process is better to select a star in the meridian and celestial equator. Basically first sincronize on that star and the the ttube move to the place where the star shoud be if the AR axis is correctley aligned to the celestial Pole. Then we move the mechanical screws (not the buttons of the hand control) to center the star first in the finder and the in the telescope eyepiece filed of view.

Sounds very complicated (i Known) but is a very easy, intiutive and the hand control will guided you. Just follow the instructions on the screen.

Very easy and precise. More precise in fact than the most accurate polar finder of the market.

Patricio

[Mark in Macc]

Thanks for all the advice, I will try the various options suggested. I'm still waiting for delivery.

[matty4unet]

I thought i would comment as i have just boughtyour exact combo only 2 weeks ago and have been out 4 times... i was stooopidly frustrated first night with my C8 SCT and CG5 mount becaus i set it all up matched the index lines and put in the longitude and latitude my GPS app on my HTC phone told me and then the time and date blah blah. 2 star align, saw Vega... yeah i know where that is looked uptot he sky pressed enter and it was like asking a dog to chase after a stick and it just turned around and layed down instead... went to literally the opposite, i was lik huh... an hour passed after i used level 9 motor and foorced the scope around to where i knew vega was then it said i could use Sirious..; but i knew siriious was underneath me... :-/ i then realised WTF had happened... its bleleding American... the date was put in as 11/05/12 11th May 2012... BUT being american it was actually 5th November 2012.. so OBV all the stars are in the wrong place.... so a pointer for u when u first setup and are a little impatient like me and only half read the manual first. hahahah

[matty4unet]

O and if yer interested i then proceeded to align the index marks and simply put Polaris into the centre of my viewfinder with the mechanical screws etc... then setup and did the 2 star align.. Capella, Spica... then chose Daneb & vega as an extra 2... i then from vega chose saturn and it went on its merry way and pput saturn absoluteely BANG in in the entre of my 8.8 Meade UWA eye piece.... absolutely fantastic... im having a few issues wwith the alignment slewing off when doing astrophotograpnhy of more than 10-15 seconds so i have purchased the polar scope and the illuminated reticle 12.5mm eye piece to gain far superior alinging...