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lamplight
Carpal Tunnel
*****

Reged: 09/18/12

Loc: western MA, U.S.
Converted old CG-4 EQ mount to ALT/AZ! thanks CN!
      #5617938 - 01/11/13 08:17 PM

Im soooo pleased. - was able to convert my CG-4 EQ mount to ALT/AZ. Particulaly with help from the CN archives. I was going to sell this CG-4 mount as I have the CG-5 for my refractor.. but i found myself not wanting to do alignment and powerup for visual. It's somewhat tedious to get the balance perfect in order to browse with the EQ mount I find, and I end up in weird positions or having to rotate the tube.. . More often than not im bringing out my SCT due to ease of setup without power. So i realized I need to start looking around for an ALT/AZ mount.

I came across DiscMounts which i promptly lusted after. sigh...

Then i saw something about converting an EQ mount and I thought a perfect project since Ive been too lazy to even sell my CG-4. I soon realized that it wasn't so easy to get the CG-4 to work as smoothly as the ALT/AZ motions of the unpowered SCT. Then I found this old archived thread on cloudynights outlining what needed to happen.

Astroview Modified to ALT/AZ. The thread went into detail about modifying the CG-4 for ALT/AZ as well. Only took about a half hour!

So happy and I can't wait to try it (its a Cloudy Night of course). the action is smoot, and the XLT 102 is light enough/the mount is heavy enough not to require counterweights! a super grab n' go setup. very smooth action I know its going to be a delight.. plus with the slow motion controls it should be sweet to run. I seem to think I had a cover for the polar alignment scope opening so there may be a few extra parts around the house somewhere..

I did go through the trouble of taking off all the motor drive components. I want to pass them on to someone who might use them, if anyone is interested send me a PM I just need postage, otherwise you can have it. seems all in great condition, but i really haven't used it (bought used).

Please take a look at my pics and let me know if I took off all the right parts for the motor drive? I wasnt quite sure as it came all attached to the mount.
CG-4 motor drive parts and finished CG-4 ALT/AZ mount





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Jon Isaacs
Postmaster
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Reged: 06/16/04

Loc: San Diego and Boulevard, CA
Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: lamplight]
      #5618295 - 01/12/13 12:30 AM

Matt:

That's what folks used to do before mounts like the Vixen Portamount became available. You do have to be careful, in the photos, the scope is cantilevered out quite a distance, it actually looks like it's outside the tripod legs. This is risky because with the scope that far out, it is easier to tip over.

What I used to do was use the polar axis for the large rotations and the RA axis for the fine adjustments and keep the scope closer to the center so it was less likely to tip over. There maybe a peg that limits the rotation of the polar axis that needs some attention, sometimes they just unscrew.

I would keep the motor drives, you may decide to use this mount for a small refractor and do some astrophotography.

Jon

Edited by Jon Isaacs (01/12/13 12:32 AM)


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mrvolt
newbie


Reged: 02/20/11

Loc: MN
Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: Jon Isaacs]
      #5618394 - 01/12/13 02:35 AM

Hi Matt,
Very nice job on the conversion to alt/az. You will find it is very stable at high powers. I purchased almost the same setup last year for our family, a celestron 102ed on the cg-4 mount. We very soon converted it to alt/az, the slow motion controls work out great. In your pic you have it out past the legs, I tend to swing it back in over the center of tripod for a bit more stability inuse. I can't understand why more folks don't try this. The cg-4 is easily up to the task and very smooth with its dual ball bearings.
Again, congrats on the job. I think you will like it for qiuck looks.
All the best,
Tony


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lamplight
Carpal Tunnel
*****

Reged: 09/18/12

Loc: western MA, U.S.
Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: Jon Isaacs]
      #5618619 - 01/12/13 08:51 AM

Quote:


What I used to do was use the polar axis for the large rotations and the RA axis for the fine adjustments and keep the scope closer to the center so it was less likely to tip over. There maybe a peg that limits the rotation of the polar axis that needs some attention
Jon




Not sure what you mean by this, but in the thread I linked to there was some lengthy discussion about the polar scope hole needing to be pointed UP (90*) for best results which is what I had to do. You make a good point and it is indeed not cantilevered out too far.. Feels very center weighted while rotation completely around 360 deg. (No degree symbol on iPad!!!). It's not out past the legs.. And they're not extended even. It is right at the edge when positioned between two legs. BUT I can get it even closer which brings up another question. I had mounted a little say 8" dovetail onto the 12" dovetail because I wanted to use the slots it had to take advantage of the little extra locking screw on the mount. I can def get rid of one of these dovetails.. I want to try the shorter one for said reason, I hope that is stable enough distance for the rings to be spread. Ill do that today which will get me an inch closer. It doesn't feel tippy at all even with pressure sideways to test it but ill still do what I can just in case.

Why I'm so excited Is not To have to spend more money. I have a cg-5 which I can use if I want eq mount and or tracking or pics. The Orion mount for the reflector. I do use the eq for refractor so infrequently I might even consider selling the cg-5 since I have the Orion mount.mhmm..

So that in mind, motors just sitting here.. And someone asked already so they're to be gone.

Thanks Jon!


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Eric63
scholastic sledgehammer


Reged: 06/16/12

Loc: Ottawa, Ontario
Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: lamplight]
      #5618632 - 01/12/13 09:08 AM

I did the same with my EQ3, however I also use the counterweight bar and one of the weights (especially if I have the 6" Newt mounted).

Eric


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Jon Isaacs
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Loc: San Diego and Boulevard, CA
Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: lamplight]
      #5618650 - 01/12/13 09:21 AM

Quote:


Not sure what you mean by this, but in the thread I linked to there was some lengthy discussion about the polar scope hole needing to be pointed UP (90*) for best results which is what I had to do. You make a good point and it is indeed not cantilevered out too far.. Feels very center weighted while rotation completely around 360 deg.




The question is, what happens when it gets bumped at night, How far does it have to tip to become unstable.... I never liked having the scope so far away from the center.

Anyway, an EQ mount like the CG-4 has 4 axes. The RA, the DEC as well as a third axis which goes through the center of the hub. There is also the Altitude axis which is used to set the elevation of the mount, currently this is set to zero degrees. Finally there is the original Azimuth axis (I incorrectly called it the Polar axis) that is normally used to to align the mount so it is pointing due north.

In the current configuration, you now have two azimuth axes. If you use the original Azimuth axis for your course azimuth movements and the RA axis for the fine/slow motion controls, you can position the scope so that it is closer to the center of the tripod, a good thing in my experience.

Some mounts allow 360 degree rotation of the original azimuth axis, some do not but can be modified so that it can rotate 360 degrees.

Hope this makes sense now.

Jon


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lamplight
Carpal Tunnel
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Reged: 09/18/12

Loc: western MA, U.S.
Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: Jon Isaacs]
      #5618754 - 01/12/13 10:31 AM

Hi

No it's not clear at all.

I did just take off one of the dovetail bars and the shorter one got it closer by maybe 3/4" to the central axis of balance for the whole tripod. I can tip a leg up about 6" before it starts to tip. I will pay very close attention to this and use a counterweight (0r a weight on the eyepiece tray!) if it seems too flimsy. With this scope it feels solid.

I have the declination/altitude axis of the polar scope opening set at 90 degrees, not zero. That was specifically mentioned in the thread and in fact I found I had to do it that way vs 0 degrees. I have it the exact same way Dave does in his thread. I forget what the issue was but it had to be this way to get unobstructed balanced movement.

Regarding all the axes you mention I'm not following, but as it is now there is full 360 degree smooth movement left and right, and unobstructed horizon to zenith which is all I need. If there's something important you ink I'm not getting do you have pics? That would make it easier to understand. I did search and couldn't find any other cg-4 pics from after an alt/az conversion , except Dave's in that thread.


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CJK
professor emeritus


Reged: 12/05/12

Loc: Northeast TN
Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: lamplight]
      #5618765 - 01/12/13 10:36 AM

Quote:

(No degree symbol on iPad!!!).




Actually, there is: press and hold the '0' (number zero) until you get a popup that allows you to choose '0' or '°'

-- Chris


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lamplight
Carpal Tunnel
*****

Reged: 09/18/12

Loc: western MA, U.S.
Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: CJK]
      #5618769 - 01/12/13 10:39 AM

Oh good. Tanks! °

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lamplight
Carpal Tunnel
*****

Reged: 09/18/12

Loc: western MA, U.S.
Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: lamplight]
      #5618778 - 01/12/13 10:43 AM

Adding the larger white counterweight above the eyepiece holder raised the tipping point to 7.5" roughly, took that off and the smaller counterweight added below the EP holder raised tipping point to 7". I haven't tried both but individually they create a slightly more stable center of gravity. Without appendages.

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newtoskies
Pooh-Bah


Reged: 07/15/12

Loc: SE Ma.
Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: lamplight]
      #5618796 - 01/12/13 10:53 AM

Very cool Matt. I'm gonna have to try this with my mount.

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Jon Isaacs
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Loc: San Diego and Boulevard, CA
Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: lamplight]
      #5618799 - 01/12/13 10:54 AM Attachment (49 downloads)

Quote:

I have the declination/altitude axis of the polar scope opening set at 90 degrees, not zero.




You're right, 90 degrees, that's I have done it, I was trying to decide from your photos which it was, 0 or 90.

Anyway, here's a photo that hopefully will explain what I am trying to say, notice how the scope is over the center of the mount rather than cantilevered out near the edge. With a long scope like yours, you probably cannot bring it all the way in.

Jon


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mrvolt
newbie


Reged: 02/20/11

Loc: MN
Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: Jon Isaacs]
      #5618941 - 01/12/13 12:05 PM

Hi Matt,

Here is a quick pic of my setup. The only difference is that I run both slo-mo controls on one side. One short one long, makes it so easy to use them both without ever taking your eye away from the eyepiece. Tipping is not much of a problem.

Tony


I tried to post a picture from my ipad, but when i click on the choose file, on CN, i get no action or response. I'm new to all this:)

Edited by mrvolt (01/12/13 12:22 PM)


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newtoskies
Pooh-Bah


Reged: 07/15/12

Loc: SE Ma.
Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: Jon Isaacs]
      #5618981 - 01/12/13 12:27 PM

That pic helps a lot Jon. I'm gonna play around with mine today and see how this all works.

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lamplight
Carpal Tunnel
*****

Reged: 09/18/12

Loc: western MA, U.S.
Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: newtoskies]
      #5619038 - 01/12/13 01:03 PM

Oh ok that makes sense. I just loosen a clutch to swing the scope around and it cantilevers moreover the center just like your picture... Just need to observe from a specific side of the tripod if i want it more centered point of gravity. Perfect! Plus the weights help too and would be more effective if lower but it seems good. Thanks again!

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KerryR
Post Laureate
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Reged: 12/05/07

Loc: SW Michigan
Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: lamplight]
      #5619118 - 01/12/13 01:56 PM

I prefer alt-az mounts, but not if they're not simpler than an EQ mount.

I mean, If I'm going to carry an EQ head out the door, why not just use it in EQ mode, especially if I've gotta counterweight it anyway?


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CJK
professor emeritus


Reged: 12/05/12

Loc: Northeast TN
Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: mrvolt]
      #5619225 - 01/12/13 03:00 PM

Quote:

I tried to post a picture from my ipad, but when i click on the choose file, on CN, i get no action or response. I'm new to all this:)




Strangely, it works for me on my iPad 3 but not on my original iPad. I bet (but don't know for sure) it has to do with the difference in JavaScript versions between iOS 5 & iOS 6.

-- Chris


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Jon Isaacs
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: KerryR]
      #5619227 - 01/12/13 03:00 PM Attachment (40 downloads)

Quote:

I prefer alt-az mounts, but not if they're not simpler than an EQ mount.

I mean, If I'm going to carry an EQ head out the door, why not just use it in EQ mode, especially if I've gotta counterweight it anyway?




A couple of thoughts:

- I prefer alt-az mounts, they are easier to point and generally more comfortable, no tube rotation, simple to use.

- For most mounts, most telescopes, there is no need for the counter weight when a GEM is used in the ALT-AZ mode. An EQ mount used alt-az is balanced, the pivot point goes through the center of gravity of the scope. The only possible purpose for the counter-weight is to keep the weight centered over the tripod but with the technique I discuss above, that is not necessary. These mounts are nimble as normal ALT-AZ mount.

Many of the smaller Gems, for example, the EQ-1 and EQ-2, the CG-2 and CG-3 can be used in the alt-az mode without any changes they work quite well. Two notable mounts are the Vixen Polaris and the Mizar mount of a similar size. Both these are high quality mounts, seemingly designed to be used either way, GEM or ALT-AZ.

(The photo is the Mizar GEM in the ALT-AZ mode)

Jon


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lamplight
Carpal Tunnel
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Reged: 09/18/12

Loc: western MA, U.S.
Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: KerryR]
      #5619422 - 01/12/13 04:44 PM

Quote:

I prefer alt-az mounts, but not if they're not simpler than an EQ mount.

I mean, If I'm going to carry an EQ head out the door, why not just use it in EQ mode, especially if I've gotta counterweight it anyway?




But I'm not "counter" weighting it at all. Just 7" added under the EP holder so Jon doesn't worry


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lamplight
Carpal Tunnel
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Reged: 09/18/12

Loc: western MA, U.S.
Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: Jon Isaacs]
      #5619433 - 01/12/13 04:50 PM

I can see how the mount design on that one makes for a more central point of balance over the tripod.. The cg-4 is a bit different.. But not a ton. I can't wait to use it this way.. I've been dragging my SCT out for manual alt/az browsing now ill only do that if I need a little more umph in light gathering and magnification. Thanks for the help guys. This is in a way. My first bargain in this hobby as far as I'm concerned

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Jon Isaacs
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Loc: San Diego and Boulevard, CA
Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: lamplight]
      #5619463 - 01/12/13 05:09 PM

Quote:

I can see how the mount design on that one makes for a more central point of balance over the tripod.. The cg-4 is a bit different.. But not a ton. I can't wait to use it this way.. I've been dragging my SCT out for manual alt/az browsing now ill only do that if I need a little more umph in light gathering and magnification. Thanks for the help guys. This is in a way. My first bargain in this hobby as far as I'm concerned




Matt:

I have an EQ-3 which is essentially the same as the older CG-4, the Mizar mount is ideal for conversion, there is absolutely nothing to modify or change. But the CG-4 still can be used effectively as an ALT-AZ mount. You are chomping at the bit, ready to go, just waiting for some clear skies.

Jon


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Noisykids
sage
*****

Reged: 06/01/11

Loc: ma
Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: Jon Isaacs]
      #5619553 - 01/12/13 06:00 PM

Seriously bemused here to find this thread. i tried converting the eq mount that my st-120 came with but couldn't get the head to go to 90 degrees. i wanted something i could grab and go and it wasn't really working out. i just took the whole head apart to locate the hard stop on the outside and it works. great. how do i explain to the war department the versa go that is supposed to be delivered monday? actually i don't care for the legs on this mount so i will probably keep the versa go. if i had found this thread two weeks ago i would be that much closer to the 8" edge hd.

eta 1/14--- the versa go is set up in the corner of the living room with an 80mm eon, an ra finder and a telrad. looks cool. my lovely wife took one look at it and remarked "is that the R2D2 model?" i kind of set her off when i brought the box in the house by asking if she noticed if the delivery guy dropped it. i shook it and it rattled. i said "this is a $6000 telescope." just had everything out looking at jupiter. it does what i want.

Edited by Noisykids (01/14/13 06:18 PM)


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lamplight
Carpal Tunnel
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Reged: 09/18/12

Loc: western MA, U.S.
Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: Noisykids]
      #5619850 - 01/12/13 09:39 PM

Oh that's unfortunate timing. Depending on the vendor , can you just return it unopened and brand new? The war dept (ha!) won't have anything to say.

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Noisykids
sage
*****

Reged: 06/01/11

Loc: ma
Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: lamplight]
      #5620750 - 01/13/13 01:02 PM

she wouldn't bustmy chops anyway. just looked at your moon photos. nice job. i seem to have trouble getting them to focus clearly. where exactly is west central ma? i describe my location at south central ma. i'm thinking millbury, brookfield,something around there, oxford, dudley,?

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newtoskies
Pooh-Bah


Reged: 07/15/12

Loc: SE Ma.
Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: Noisykids]
      #5620762 - 01/13/13 01:07 PM

Too bad you guys aren't closer, would be great to hook up in the Spring for a small star party.

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lamplight
Carpal Tunnel
*****

Reged: 09/18/12

Loc: western MA, U.S.
Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: newtoskies]
      #5621147 - 01/13/13 04:21 PM

Hi

Northampton ma. I'd consider berkshires western am but people do call this western mass.. So, wEll there ya go.

I'm new at the photos but here's what I found so far: camera has a manual focus assist screen that can zoom in many times just for focus.. I forget, and it varies I think.. It can temporarily show a screen that is zoomed many times so I can get better focus.. The other thing that I've been realizing is the exposure needs to be a lot quicker than I originally was doing because of the motion blur of the planets' / moon movement.

Where are you noisy kids?

Rob I'm down there near buzzards bay for family like i said so I'm sure we can do a meetup when warmer. It's my wife's folks and I usually don't go down much but they have incredible horizons and what with meeting up ill probably go down a bit more often this year


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Noisykids
sage
*****

Reged: 06/01/11

Loc: ma
Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: lamplight]
      #5621256 - 01/13/13 05:14 PM

i'm in hopedale, next to milford,just off 495, half hour from worcester one way and framingham the other. i'm right on the edge of a red zone but 20 minutes towards uxbridge or whitinsville or upton and the color goes to a tan thing.
my canon rebel doesn't have an internal zoom so i have to drag the laptop outside and that's just more stuff.


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newtoskies
Pooh-Bah


Reged: 07/15/12

Loc: SE Ma.
Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: Noisykids]
      #5621542 - 01/13/13 08:00 PM

noisykids, hey your right up the road from me...45min to an hour.

I was thinking of later getting the Rebel. Will see how you make out with images for reference.


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lamplight
Carpal Tunnel
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Reged: 09/18/12

Loc: western MA, U.S.
Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: newtoskies]
      #5622745 - 01/14/13 02:02 PM

Quote:

Very cool Matt. I'm gonna have to try this with my mount.




what i didnt mention is the two plastic covers where the latitude scale is and on the other side where it says Celestron: they cracked a little bit when coming off on mine , so if you try it just be aware you may be making the mount uglier. i didnt really care so perhaps i could have used a little more finesse. maybe a haor dryer on each side might help soften up the glue before trying that if concerned.


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lamplight
Carpal Tunnel
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Reged: 09/18/12

Loc: western MA, U.S.
Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: lamplight]
      #5622756 - 01/14/13 02:08 PM Attachment (24 downloads)

pic of added weight underneath the leg stabalizer/tripod mount. a quick test showed a slightly better center of gravity. the bigger of the two weights fits above the EP holder as well for added weight. i dont think i really need it but you get the idea:

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lamplight
Carpal Tunnel
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Reged: 09/18/12

Loc: western MA, U.S.
Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: lamplight]
      #5622763 - 01/14/13 02:10 PM

obviously the same weight , lower, would provide way more stability but trying to keep things lean and mean.

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Sarkikos
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Loc: Scotophobe Maryland, USA
Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: lamplight]
      #5622784 - 01/14/13 02:25 PM

You used to be able to get wooden leg replacements for the standard legs supplied with the CG-4. I bought wooden legs for my CG-4 from Hands On about five years ago. They make for a much sturdier - though somewhat heavier - mount.

Mike


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Jon Isaacs
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Reged: 06/16/04

Loc: San Diego and Boulevard, CA
Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: Sarkikos]
      #5622836 - 01/14/13 03:01 PM

Quote:

You used to be able to get wooden leg replacements for the standard legs supplied with the CG-4. I bought wooden legs for my CG-4 from Hands On about five years ago. They make for a much sturdier - though somewhat heavier - mount.

Mike




Mike:

Was your a new CG-4 with the 1.75 inch diameter stainless steel legs or the older one with extruded aluminum legs. In my experience, the aluminum legs were a weak link and replacing them with wood was a definite improvement. The 1.75 inch SS legs are quite sturdy and should be more than sufficient.

Jon


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Sarkikos
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: Jon Isaacs]
      #5623356 - 01/14/13 08:25 PM

Those old legs have been up in the attic for about five years now. I believe they were the aluminum legs. I remember they were light and pretty flimsy and that the wooden legs were an obvious improvement.

Mike


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Jon Isaacs
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: Sarkikos]
      #5623444 - 01/14/13 09:20 PM

Quote:

Those old legs have been up in the attic for about five years now. I believe they were the aluminum legs. I remember they were light and pretty flimsy and that the wooden legs were an obvious improvement.

Mike




Mike:

Those old aluminum legs were used on the CG-5s too and pretty flaky. When Celestron came out with the CG-5 Advanced Series they upped the Ante with the 2 inch Stainless Steel legs, then upgraded the CG-4 to 1.75 inch aluminum legs, it forced the other manufacturers to follow suit...

I have an EQ-3 which is essentially the same as your CG-4, Wooden legs certainly helped stabilize that mount.

Jon


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lamplight
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: Jon Isaacs]
      #5624418 - 01/15/13 01:32 PM

I just picked up some wood GTO legs that can for this and claim to minimize shake. Not too costly and given your comments here thought what the heck. The 1.75" seem more than fine but it will be interesting to compare.

Especially since I was experimenting with my 10" reflector n this mount and it, gasp, works. Little obstruction issues at closer to zenith and I know how to deal with that if this becomes a regular thing. I'm surprised it balanced Ok without counterweights . Clouded over so didn't get to experiment long, 5 minutes.. And was on my deck so wasn't really sure how much shake there was since the deck had plenty. Nice to have options.


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newtoskies
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: lamplight]
      #5624441 - 01/15/13 01:41 PM

I'll be switching my mount over to alt az this evening to give me something to. I planned on using the EQ but remembered that I can't see Polaris due to a neighbors light that is some times on, Mall LP and a big tree. I'll use the EQ set up at a dark site or a field close by when it warms up.

Very cool thread Matt.


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lamplight
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: newtoskies]
      #5624461 - 01/15/13 01:50 PM

Well it's not a quick and easy back and forth.. But not rocket science either. Just rediscovering what a lot of folks did back in the day apparently

I can't see Polaris from my observing spot too.. It can be polar aligned pretty well though even so.. They helped me figure that out here a while back , pm me if you want a link to the thread.. I forget what it was called (thread title).

Good luck let me know how you make out. Oh be sure the lock the flange in place like he shows how to do in the thread (I was only able to get one screw in but its tight and holds. ) otherwise the scope will flop when rotated


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newtoskies
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: lamplight]
      #5624488 - 01/15/13 02:11 PM

Thanks Matt. I'll grind down the one spot to allow it to flip. I figure I have lots of time as it doesn't seem like we'll have clear skies for a while.

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lamplight
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: newtoskies]
      #5624500 - 01/15/13 02:16 PM

Ok yes that's the part I'm talking about.. Once you get it flipped through I had to put the "stop" back on so it wouldn't flip back and forth.. I think you know what I mean. Wish I had a grinder! In that case your conversion should be a lot easier to manage than what I had to do!

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newtoskies
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: lamplight]
      #5624508 - 01/15/13 02:19 PM

Yeah that way I don't have to take the caps off and un bolt the mount just to flip. Once it clears after grinding it's only a matter of taking off the two hex bolts and plate, flip, then bolt back on.

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Jon Isaacs
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: lamplight]
      #5624610 - 01/15/13 03:07 PM

Quote:

I just picked up some wood GTO legs that can for this and claim to minimize shake. Not too costly and given your comments here thought what the heck. The 1.75" seem more than fine but it will be interesting to compare.




The Wooden Legs are a nice upgrade for a mount with the extruded aluminum legs, they are a meaningful upgrade to the Vixen Portamount. But the new GS-4 with it's 1.75 inch SS legs are a different story, they are used on mount like the Orion Sirius which is rated for 30lbs.

Jon


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newtoskies
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: newtoskies]
      #5624662 - 01/15/13 03:38 PM

I couldn't resist and went ahead and changed mine over. Took about 20 minutes to remove bolts and grind the flange and tongue.

Removed the front plate.


The flange that stops it was first ground down, but the plate does not go back on because the holes don't line up.


An easier way is to just grind down the tongue. This allows it to clear the flange and rest above the plate after it's screwed back in place.


The scope was mounted and it moves freely, and closer to the center and not hanging out past the legs.





I don't think the weights are needed but I'll find a bolt long enough to hold the smaller/lighter weight. I also found it easier to carry the mount with scope out the door. The only thing is that it is a few inches lower, but the legs can be extended.
This is very easy to switch back to the EQ set up. Now I just need clear skies to test the new scope and alt az out.


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lamplight
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: newtoskies]
      #5624712 - 01/15/13 04:03 PM

Nice! Who's next?

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newtoskies
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: lamplight]
      #5624721 - 01/15/13 04:09 PM

yep, was easy to do. So now it looks very cool just sitting there... Nothing but clouds here.

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lamplight
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: newtoskies]
      #5634944 - 01/21/13 01:08 PM

Hey Rob

i noticed last night that i would like to have my AZ/alt knobs on the same side as yours is pictured. i cant do that as the knobs hit each other so i cant swing the scope fully up/down if i have knobs on the same side. . you appear to have some extensions that mine didn't come with for your RA/DEC knobs.

just ordered some flexible slow mo controls from scopestuff!


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Knygathin
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: lamplight]
      #5640409 - 01/24/13 10:51 AM

I guess there must two alternate ways of changing the CG-4 from eq mount to altaz! I turned the altitude axis the other way, to 0 degrees instead of 90 degrees. It was a much easier conversion. And the telescope looks to be eaqually near the center of the mount as when turning to 90 degrees.

The only con is that the balancing weight knocks into one of the tripod-legs when viewing objects near the horizon. But on the other hand, the remote controls are horizontally parallell to each other, which makes it much more comfortable holding them, than when one is top of the other.


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lamplight
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: Knygathin]
      #5641471 - 01/24/13 08:57 PM

That's kind of why people recommend putting it at 90°, but if it works for you it is a job well done. Actually I guess there's at least 3 ways that we covered: your way, going the flange down, take it apart the way I did. I like the grind method jus haven't tried that yet. Wish I'd had thought of it before busting off my plastic bolt caps.

Welcome to CN btw


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newtoskies
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: lamplight]
      #5641584 - 01/24/13 09:50 PM

Very good all round mount eh. Yeah Matt by grinding the tongue down there is no need to unbolt anything.

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johnnyha
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: newtoskies]
      #5641641 - 01/24/13 10:22 PM

I'm not quite up to speed with exactly how this is done - are the motors still operational? I would LOOOOOVE for my DM6 to have a handpad and motors. I'm not talking about tracking obviously but just being able to move the scope with the handpad would be great.

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lamplight
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: johnnyha]
      #5641710 - 01/24/13 11:09 PM

Johnny

Now that's kind of a different ball of wax .. I took the motor off mine and gave it away to someone here on CN.. But that's a super interesting thought you have.. In fact I had been eyeing my cg-5 wondering if there was a non destructive motorized alt-az conversion possible to do just as you say.. In that mounts case it might be just as simple to keep as EQ really.. and That's a little different than motorizing a non powered alt-az, I'd be real curious what you might find out.. I never thought of trying my motors and hand controller!

Oh rob btw I put a longer dovetail bar on and it made a HUGE difference in stability.. Shake stops in a second or two vs 5+!


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johnnyha
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: lamplight]
      #5642974 - 01/25/13 04:59 PM

So Matt, are the gears stripped out or...? Is it indeed possible to make this conversion with the motors still working?

I have no plans to motorize my DM6 but I definitely would love the capability.


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lamplight
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: johnnyha]
      #5643013 - 01/25/13 05:27 PM

Hi

The motor should work fine like this still, from what I can tell, though I don't have them any more as I mentioned. Pretty sure rob doesnt have motors either. So I can't say for certain. You have the dm6 on a cg4? If the gear bolt are still accessible I don't see why it wouldn't work. The guy I gave my motors to is on CN and has used the cg-4 in alt-az and eq mode . Maybe he will see this and can answer


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johnnyha
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: lamplight]
      #5643054 - 01/25/13 05:50 PM

Thanks Matt and to clear up any confusion, my DM6 is a normal DM6 on a Planet tripod and I just daydream that I had a motorized handpad instead of manually moving it.

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SkipW
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: Knygathin]
      #5643199 - 01/25/13 07:22 PM

Quote:

I guess there must two alternate ways of changing the CG-4 from eq mount to altaz! I turned the altitude axis the other way, to 0 degrees instead of 90 degrees. It was a much easier conversion. And the telescope looks to be eaqually near the center of the mount as when turning to 90 degrees.

The only con is that the balancing weight knocks into one of the tripod-legs when viewing objects near the horizon. But on the other hand, the remote controls are horizontally parallell to each other, which makes it much more comfortable holding them, than when one is top of the other.



If you're going to do this, why not just tilt it up to match your latitude and point it generally north? It's easy to track objects if you do that.

Maybe I'm missing something, but I see zero advantages to doing this instead of just using it as the equatorial mount it was designed to be.


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Knygathin
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Reged: 12/31/09

Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: SkipW]
      #5643273 - 01/25/13 08:08 PM

Quote:


If you're going to do this, why not just tilt it up to match your latitude and point it generally north? It's easy to track objects if you do that.

Maybe I'm missing something, but I see zero advantages to doing this instead of just using it as the equatorial mount it was designed to be.




With altaz mode, one remote control knob will move the telescope tube left to right, and the other knob will move it up and down. While looking through the telescope you can move along in the sky anywhere you want, by turning the two knobs.

With equatorial mode, the remote control knobs will not move the telescope tube in this logical left/right and up/down manner. Instead it's like having a steering wheel on a car that is not directly connected to the wheels. It's difficult to steer it to where you want it. With equatorial mode you need the coordinates of an object, and then set the setting circles on the telescope to the same coordinates. You can't move and explore the sky spontaneously with the two knobs.


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CJK
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: Knygathin]
      #5643285 - 01/25/13 08:16 PM

Actually, with an equatorial mount, the movements are just as logical -- it's just that you have to think of movement with reference to the celestial coordinate system instead of one based on the local horizon.

I'm not saying that it's easy to do that, but if you visualize things that way, it's actually pretty easy to move around with an EQ mount.

-- Chris


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Knygathin
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: CJK]
      #5643323 - 01/25/13 08:40 PM

Quote:

Actually, with an equatorial mount, the movements are just as logical -- it's just that you have to think of movement with reference to the celestial coordinate system instead of one based on the local horizon.

I'm not saying that it's easy to do that, but if you visualize things that way, it's actually pretty easy to move around with an EQ mount.

-- Chris




Hmmm. . . seems I have lot to learn. That sounds like a cosmological perspective, a fifth dimension perhaps, that my Earth evolved hands and eyes, connected by nerve centers in the brain, can't grasp. It certainly is a different kind of logics.

In eq mode, a sky object may be just outside of view, but no amount of fine tuning of the knobs will reach that object. Instead the tube must be moved around on the axis for a long detour before the object can be reached. It is weird!



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CJK
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: Knygathin]
      #5643343 - 01/25/13 08:53 PM

This page is a good comparison of the two coordinate systems. The diagram at the bottom of the page is pretty helpful for visualizing the RA/dec system.

-- Chris


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johnnyha
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: CJK]
      #5643369 - 01/25/13 09:13 PM

One of the main advantages of alt/az is the focuser/diagonal/finder stays in the same basic area, and you don't have the eyepiece rotating into awkward positions.

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Sarkikos
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: johnnyha]
      #5643414 - 01/25/13 09:35 PM



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newtoskies
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: newtoskies]
      #5643665 - 01/26/13 01:00 AM

I will use the EQ when it warms up and I have longer viewing sessions. For now the Alt-az works great for just roaming and finding objects. No need for tracking for short sessions and just hopping around. Having a mount that can be converted over from EQ to alt-az, and back again kind of gives you two mounts in one.

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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: newtoskies]
      #5643682 - 01/26/13 01:21 AM

I'm curious if anyone is using the motors. Do you realize how much the Half Hitch people are charging to put motors on the Nova Hitch? I think they call it "robotic control" or somesuch...

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lamplight
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: johnnyha]
      #5644103 - 01/26/13 10:21 AM

You've got me thinking of trying this. Brilliant. The cg-4 stuff is quite cheap as things in this hobby go. Kind of silly I just gave mine way. I'm thinking one of the discmounts would be awesome for my reflector.. The cg-5 computerized /tracking mount looks like the same physical setup for rotating it to 90° (hmmmmmmm......)

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newtoskies
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: lamplight]
      #5644351 - 01/26/13 12:52 PM

ok Matt, your the official tester..lol Let us know what you come up with.

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SkipW
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: Knygathin]
      #5644570 - 01/26/13 03:03 PM

Quote:

Quote:


If you're going to do this, why not just tilt it up to match your latitude and point it generally north? It's easy to track objects if you do that.

Maybe I'm missing something, but I see zero advantages to doing this instead of just using it as the equatorial mount it was designed to be.




With altaz mode, one remote control knob will move the telescope tube left to right, and the other knob will move it up and down. While looking through the telescope you can move along in the sky anywhere you want, by turning the two knobs.

With equatorial mode, the remote control knobs will not move the telescope tube in this logical left/right and up/down manner. Instead it's like having a steering wheel on a car that is not directly connected to the wheels. It's difficult to steer it to where you want it. With equatorial mode you need the coordinates of an object, and then set the setting circles on the telescope to the same coordinates. You can't move and explore the sky spontaneously with the two knobs.



Sure you can. You can point anywhere in the sky you want, too, except maybe very close to the pole (alt-az mounts have this problem near the zenith). It takes a little getting used to, but not a lot, and in exchange tracking is significantly easier - you only need to move one axis to track.

If you set an equatorial mount up with the polar axis horizontal, as suggested in the post I responded to, it will not behave the way you just describe. Which of the slow-motion controls will cause the telescope to move up and down, or left and right, depends on where in the sky you're looking, unlike a true alt-az. It will also be very difficult to point to objects in the directions the polar axis is pointed due to a condition known as gimbal lock. This is the same in the polar region for an equatorial and near the zenith for an alt-az, but now you have two of them.

Let's review the cons to setting up this way:
Still need the counterweight (alt-az may not).
Counterweight hits the tripod.
Need two motions to track (eq needs just one).
Slow-motion controls don't move the telescope in a left-right-up-down manner (alt-az does, if that's what you want).
Gimbal lock in two directions instead of one.
Still need to do a meridian flip (alt-az doesn't, except when passing near zenith).

Now, lets review the pros:
<crickets>

Equatorial and alt-az mounts each have certain advantages. Setting up an equatorial mount with the polar axis level has none of the advantages of either, as far as I can tell, and none of its own (unless you're near the equator, then it's an equatorial mount if you align the PA north-south).


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lamplight
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Re: Converted old CG-4 EQ mount to ALT/AZ! thanks CN! new [Re: SkipW]
      #5649985 - 01/29/13 10:19 AM Attachment (21 downloads)

Rob: added the slo mo extension and filed down the tongue part so i could flip back and forth easier (unlikely, but still it also allows both screws to go back in, a neater job).

Edited by lamplight (01/29/13 11:41 AM)


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