Bob Rumfield
member
Reged: 08/29/09
Posts: 20
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I am a real novice when it comes to this stuff, but I finally have a process and limited understanding about CGEM mount alignment. I received my new CGEM mount several weeks ago, actually in late August. Prior to that, I used an old Vixen mount and wanted to be able to handle heavier equipment, so I purchased the CGEM. I have experienced problems, problems, problems since first darkness trying to do a good two star align. I finally bought a polar align scope. That still did not help. My usual problem was not the alignment mechanically with Polaris but the later Two Star align. Then I ran into cloudy skies in Eastern PA. Actually, 10 days of them. Well tonight it cleared off enough for me to try a few things. First of all, I have an NP 101 refractor, so how do you mount it and in what direction on the mount? The manual looks wrong to start with. If the mount is set to the Startup Procedure on page 17 of the manual you should have the refractor set on the mount so that it points North. With a Polar Alignment Scope you can fine tune your mount on Latitude and Longitude using the manual adjustments as specified in the manual. OK, so now all is pointing at N.C.P. Now when you turn your mount on you need to do an UNDO until you get to the Utilities Menu. Scroll using the Up / Down buttons until you get to the Factory Settings and reset the unit as when you rec'd it. You are almost there. It will instruct you to turn off the mount. I waited the universal 10 second time before rebooting. Then I went thru the Initial Alignment process and a Two Star Alignment with a later verification by pressing List and Named Star and choosing Polaris. It was dead on. Then I skewed to Jupiter, dead on again. Finally, the mount is set up. As a day time alignment I used a Sharpie to mark my tripod legs on my deck. I hope this helps those of you who have been having alignment problems with the CGEM mount. Again, I want to stress that I am not very knowledgeable about this stuff and might have left out a few steps. But I can finally feel good about my purchase.
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Lane
Carpal Tunnel
Reged: 11/19/07
Posts: 1514
Loc: Frisco, Texas
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I think it just takes some practice. But remember that a polar alignment is not required for the GOTO to work properly, it is only needed to make tracking accurate. You can be way off of polaris and it will still get good GOTOs. The only issue with not having the mount level and aimed at polaris is that the scope will not be able to find the initial alignment stars by itself, but that is not a problem as long as you know where they are. You use the hand controller to find and center them and after that everything will be fine.
At higher magnifications tracking will lose objects fast if you don't have a semi-close aim at polaris and a level mount.
To get really spot-on goto's you need to do 2 alignment stars and then 2 calibration stars. After a few hours of viewing you may also want to replace some of the calibration or alignment stars as it explains in the user guide since goto's tend to start getting off a little.
Also make sure you have the real-time clock turned on so you don't have to keep entering date/time everyting you set up the mount.
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Mounts: CGEM, ORION SIRIUS, AT Voyager/motorized
SCTs: C6, C8, C9.25, C11,
Refractors: TV Pronto, Orion ED80
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johnmarkw
member
Reged: 07/29/09
Posts: 12
Loc: Virginia
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I also am new to the CGEM. I can't find in the manual the option for real-time clock. How do you set this? Thanks
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Mark W.
C 9.25
CGEM
Agena 35mm SWA
Baader Hyperion 8 - 24
Nikon D700
Nikon 180mm f2.8
Nikon 105VR f2.8
Nikon 50mm F2
Nikon 20mm f2.8
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stevecoe
"Astronomical Tourist"
Reged: 04/24/04
Posts: 2644
Loc: Arizona, USA
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Bob;
I have no polar scope, but I have done some piggyback astrophotography after using the Polar Align software routine. I get Polaris centered in the hole in the polar shaft as a starting point and then do a two star alignment. Then choose the Polar Alignment routine and the scope will point to a star and you use the handpaddle to get it centered. Hit Enter and the scope will slew to the place in the sky where the star ought to be if you were on the NCP (North Celestial Pole). Do NOT use the handpaddle, most the scope physically so that the star is centered at high power and you are one the pole. I then turned off the scope and did another Two Star align.
Steve Coe
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TeleVue 102 refractor on CGEM mount
10 inch f/4.7 Newtonian
Author "Deep Sky Observing" Springer-Verlag
Author "Nebulae and How to Observe Them" Springer
Canon Xt astrocamera with Hutech modification
Edited by stevecoe (09/14/09 03:41 PM)
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R Nitzel
member
Reged: 01/14/09
Posts: 52
Loc: Corpus Christi, TX
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Here's my routine:
* Orient the mount north as best as I can (I've actually got a mark on the fence to aim at now to speed things up)
* Make sure mount is level using the bubble level on the mount
* Align the RA and DEC index marks to their home position
* Turn on the power switch
* Hit Enter to begin align
* When it asks about site/location, hit Undo
* Set current time and date, verify site location is correct
* Select 2-star align
* Mount slews to first star - depending on how well I pointed and leveled initially, it may be close, or it may be a little ways outside the finder scope.
* Center and fine-tune the first star
* Mount slews to second star - usually much closer. Center and fine-tune second star
* Add at least one calibration star - same method as above
* GOTO an appropriate star (away from pole, etc.)
* At CGEM Ready prompt, hit Align and choose Polar Alignment, recenter star, then mount will slew away and then back NEAR the star. DO NOT use the hand controller to recenter this time. Use the manual adjustments to center the star.
* You're now polar aligned
* Try a couple of GOTO's. Depending on how much I moved the mount, I will sometimes add another calibration star or two.
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____________________________
Ryan
CGEM 800 Hyperstar 3
Orion ST80
DSI III
SSAG
A lot to learn
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Bob Rumfield
member
Reged: 08/29/09
Posts: 20
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Wow, thanks for the tips. I cannot wait to try them. I am looking forward to seeing how a long track holds up. Clearer skies in Eastern PA will facilitate this aspect. Thanks for the alignment tips.
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tturtle
journeyman
Reged: 03/03/09
Posts: 9
Loc: Florida
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The procedure from Ryan is what I follow and it works well for me. The only thing I would add is that the scope has an internal clock. You do not need to set the time and date every time you turn on the mount. My scope came with the internal clock turned off, which I reactivated by resetting the mount to factory default. The manual does not explain this very well.
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-tom
CGEM 925
Baader Hyperion Zoom 8-24
6mm TV Radian
G3 Astro Aimer
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johnmarkw
member
Reged: 07/29/09
Posts: 12
Loc: Virginia
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So if I reset to factory default it automatically turns the internal clock on? Does it then know your time zone based on the location you give it? Do I still tell it DST and the date? What if I ever wanted to turn it off?
Any other resources for the CGEM other than the manual and the great wisdom of CN?
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Mark W.
C 9.25
CGEM
Agena 35mm SWA
Baader Hyperion 8 - 24
Nikon D700
Nikon 180mm f2.8
Nikon 105VR f2.8
Nikon 50mm F2
Nikon 20mm f2.8
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waassaabee
Carpal Tunnel
Reged: 11/26/07
Posts: 2700
Loc: Central California Coast
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Quote:
So if I reset to factory default it automatically turns the internal clock on? Does it then know your time zone based on the location you give it? Do I still tell it DST and the date? What if I ever wanted to turn it off?
Any other resources for the CGEM other than the manual and the great wisdom of CN?
Or you can read the section on Turn On/OFF RTC (Real Time Clock) on page 30 of you manual.
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Gary
34N 120W
-My kingdom for blue squares!-
WO Megrez 90FD/TV 0.8x FR/FF
AT8RC
mini Borg 50/Q-Guide/PHD
CGEM
Canon 350D Hap Griffin Baader mod - o.o
My Friend Flickr
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johnmarkw
member
Reged: 07/29/09
Posts: 12
Loc: Virginia
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Thanks Gary. Missed that about the RTC. Perhaps someone can help me with a problem I had last night. Leveled tripod and polar aligned looking through the polar shaft. Aligned the marks for RA & DEC.. Went through the startup procedure to set time, etc... Selected two star alignment and chose Arcturas. It slewed toward it, but ended up at least 15 degrees "left" of it. I used the hand controller and got it lined up. Selected the next start Mizar and the same thing. It was 15 degrees to the left again. Centered Mizar and selected a calibration star and it was still off by the same amount.
Powered off and tried the same procedure again with the same results. What am I doing wrong? It worked the night before at a different location using the same alignment procedure.
I also wondered if there is a way to get out of the two star alignment procedure? I tried undo and it keeps cycling thru stars for alignment. No other key seems to get you out.
Another issue that I had was in trying to enter the longitude it wouldn't let me put in the minutes and seconds for my location. I ended up going to the city nearest me (about 5 miles away) for the location.
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Mark W.
C 9.25
CGEM
Agena 35mm SWA
Baader Hyperion 8 - 24
Nikon D700
Nikon 180mm f2.8
Nikon 105VR f2.8
Nikon 50mm F2
Nikon 20mm f2.8
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mclewis1
Thread Killer
Reged: 02/25/06
Posts: 3947
Loc: New Brunswick, Canada
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Nearest city at 5 miles is good. Consistently 15° or so off on initial alignment stars is usually something like the DST setting or time zone.
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Mark
C11, C6, APM/TMB115, and AT80ED - Tandem mount CGE and CG-5A, WO EZ-Touch and AT Voyager
25x100s and 8x56s, T-Mount Light, Mark 1 eyeballs - Modded 350D, DSI-P, SPC900, Mallincam
Just because you can doesn't necessarily mean that you should
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stevecoe
"Astronomical Tourist"
Reged: 04/24/04
Posts: 2644
Loc: Arizona, USA
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Check the Daylight Saving Time setting and see what you get. I have been far off on the two setting stars and then added two more stars, they got better as the alignment progressed. Add those extra alignment stars.
Steve Coe
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TeleVue 102 refractor on CGEM mount
10 inch f/4.7 Newtonian
Author "Deep Sky Observing" Springer-Verlag
Author "Nebulae and How to Observe Them" Springer
Canon Xt astrocamera with Hutech modification
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Bob Rumfield
member
Reged: 08/29/09
Posts: 20
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O.K. Tonight is the big test for me on the CGEM mount alignment. It is a clear sky in Eastern PA and I have set up my scope in daylight. I am confident about my alignment process and am incorporating into my suggestions others welcomed replies. I will let you know how I make out. Maybe tomorrow night I will add the ST 2000MX to the NP101 and do a little CCD.
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Harold925
member
Reged: 07/11/09
Posts: 39
Loc: Near Charleston, S.C. Cluster
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Hello Steve,
From reading the posts here, I've noticed that the original poster and yourself turn off your mounts after completing the All-Star polar alignment. From what I've read in the manual and on the Celestron Support link, I just continue to slew to the original alignment and calibration stars after the All-Star, then move on. Has there been any other revised procedure to power down and up again after you polar align the mount? Just curious, thanks!
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Harold
Celestron CGEM, C-9.25 XLT
Orion XT8i
Celestron SkyMaster 9x63
Many Accessories
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johnmarkw
member
Reged: 07/29/09
Posts: 12
Loc: Virginia
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Update on my CGEM alignment. I was able to go out last Saturday and give it another run. I was able to get it working well after the two star alignment and two calibration stars. Near perfect goto. It still was further off than I would've expected with the two first alignment stars. Perhaps it's because the first time I used it a friend had a gps unit that he plugged in. The alignment stars weren't far off. The next time from a different location I was manually putting in the location and it was much further off initially.
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Mark W.
C 9.25
CGEM
Agena 35mm SWA
Baader Hyperion 8 - 24
Nikon D700
Nikon 180mm f2.8
Nikon 105VR f2.8
Nikon 50mm F2
Nikon 20mm f2.8
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rmollise
Post Laureate
Reged: 07/06/07
Posts: 4573
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Quote:
Update on my CGEM alignment. I was able to go out last Saturday and give it another run. I was able to get it working well after the two star alignment and two calibration stars. Near perfect goto. It still was further off than I would've expected with the two first alignment stars. Perhaps it's because the first time I used it a friend had a gps unit that he plugged in. The alignment stars weren't far off. The next time from a different location I was manually putting in the location and it was much further off initially.
A number of factors can affect how close you come to the intitial alignment stars. But it really doesn't matter. Just center 'em and keep on truckin'. In my experience, by the time you get to calibration star two or three, it will be in the main eyepiece.
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Uncle Rod
Rod's New Book:
Choosing and Using a New CAT
Available now!
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donsinger1
sage
Reged: 10/28/07
Posts: 298
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A number of factors can affect how close you come to the intitial alignment stars. But it really doesn't matter. Just center 'em and keep on truckin'. In my experience, by the time you get to calibration star two or three, it will be in the main eyepiece.
Exactly...don't be too fussy...the initial alignment stars will be somewhat off...so what? Mine are off but after two alignment stars and 2-3 Calibration stars, I can goto and put the object in the center of a CCD chip...not bad. Tracking quality substantially depends on your polar alignment - if you use the All Star Polar Alignment with a star close to the Meridian, you should have very good performance.
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Fun Stuff:)
Portland, OR
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jhenline
newbie
Reged: 02/11/09
Posts: 2
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hi all. wondering if you are using an illuminated reticle eyepiece when preforming alignment? Is it important to have an illuminated reticle eyepiece? I just got a CGEM and am waiting for weather to clear up so I can get it out. I am more interested in tracking performance rather than go-to accuracy.
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waassaabee
Carpal Tunnel
Reged: 11/26/07
Posts: 2700
Loc: Central California Coast
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IMHO, for imaging, I highly recommend an illuminated reticle EP as it fine tunes your alignments, then during the Polar Alignment Routine, you get better accuracy.
For visual, your rough polar sighting, and getting the alignment/calibration stars in the middle of the EP should be plenty.
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Gary
34N 120W
-My kingdom for blue squares!-
WO Megrez 90FD/TV 0.8x FR/FF
AT8RC
mini Borg 50/Q-Guide/PHD
CGEM
Canon 350D Hap Griffin Baader mod - o.o
My Friend Flickr
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Harold925
member
Reged: 07/11/09
Posts: 39
Loc: Near Charleston, S.C. Cluster
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Well, it's up to you, but I purchased the Orion 9x50 illuminated finder scope, along with the fairly new 20mm illuminated centering eyepiece to use with my CGEM alignments and accuracy has improved significantly. Going through the trial and error with the All-Star polar alignment was hectic at first, but now my tracking is great and I definitely like this mount. I do wish that it was a few pounds lighter. I feel that Celestron could have provided a much better operator's manual to explain the polar alignment with greater detailed instructions. Take care.
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Harold
Celestron CGEM, C-9.25 XLT
Orion XT8i
Celestron SkyMaster 9x63
Many Accessories
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