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CG-4 modification

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#1 clengman

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Posted 10 March 2011 - 01:09 PM

I'm thinking about buying my first decent scope sometime in the next year or so (I'm not talking great, I just mean better than my 60mm tasco. I'm planning spend in the $300-500 range for the whole package). In a new scope, I've been looking at the celestron omni xlt 102. (Also considering a midsize dob, but that won't apply to this question) I'm going to look around at used stuff, too and so might be buying my rig piecemeal. The celestron 102 comes on a cg4 mount and if I buy a used OTA it seems like the cg4 would be appropriate for the size scope I'm interested in as well as my budget.

I *think* I'd like an eq mount since that will make it a little easier to share my viewing enjoyment with others who have less practice tracking targets manually, but I also like doing some terrestrial viewing and I might try some starhopping which would seem to be easier with an alt az mount.

I know for some eqs it's possible to use them in alt-az mode by tilting the polar axis up to 90, but I understand the cg-4 is not meant to be used this way and the polar axis doesn't go past 60. What I'm wondering is:

1) Is there a similarly priced eq mount that would work in alt-az?

2) Has anyone tried modifying a cg-4 to use in this fashion

3) Failing options 1 and 2, is there an alt-az mount with slow motion controls available for a reasonable price? Would the Celestron #93607 (I've seen it described as "medium-duty Alt-az mount" and as "heavy-duty alt-az tripod" but I think they are the same thing) be suitable? Is that mount still being made? It was not easy to find on celestron's website. I had to search for it by product number. It didn't show up in the products menu. I appreciate any info anyone's got to share. Thanks!

Carl

#2 Trev

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Posted 10 March 2011 - 02:25 PM

Maybe PM oldtimer, he did this recently to his CG-4

#3 clengman

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Posted 10 March 2011 - 02:50 PM

Thanks Trev. I just sent him a quick message.

Carl

#4 Don Trinko

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Posted 10 March 2011 - 03:12 PM

Celestron has a alt/az for abought $100 that has slow motion controls. It is reasonably stable for a small scope. (under 6 lbs?)
As I understand it you can set the latitude for 90 degrees on an EQ mount and it then acts like an alt/az. Don T.

#5 Don Trinko

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Posted 10 March 2011 - 03:14 PM

I think I have the Celestron you are talking abought. It is decent for the price but the CG4 would be more stable especially if you get a bigger scope. Don T.

#6 avarakin

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Posted 10 March 2011 - 10:33 PM

Carl,
I suggest to go with a proper CG5 class mount. I remember I was comparing them at some point and CG4 was inferior to CG5 in many respects.
You would be surprised of how cheap you can get CG5 class mount. Some examples:
-couple of weeks back there was an older Great Polaris mount on S&S for 160
-LXD75 or CG5 Goto are often sold for ~300 on S&S
-Meade has refurbished LXD75 for 475
-there are generic versions of CG5 available for around $230 new

Alex

#7 clengman

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Posted 10 March 2011 - 11:52 PM

Just got a reply from oldtimer. He says with a little bit of filing it's possible to set the CG-4 in an alt-az configuration and that it works pretty well for him. I'm not sure what type of scope he's using on that mount.

Avarakin - I've heard of that generic cg5 mount. Where would one look for it?

thanks

Carl

#8 avarakin

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Posted 11 March 2011 - 12:19 AM

Carl,

I am not seeing them sold separately nowadays, but I see it is sold with an 8" scope:
http://cgi.ebay.com/...=item1e60d946a9

I have no idea how good or bad this scope is. Maybe you need to talk to vendor about getting mount only.
I think your best bet would be to give an ad on S&S - "WTB CG5 class mount" and wait till someone replies, maybe you will have to bump it couple of times.

Alex

#9 clengman

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Posted 11 March 2011 - 12:57 AM

Thanks for the tip. I'll definitely consider that when I'm ready to buy. I'm still not completely sold on the cg5 over the cg4, though. What's the difference in weight between the two? I think the cg5 is 42 lb. I haven't seen a figure for the cg4. I know I don't want something that's *too* light, but I am looking for something that will be easy to maneuver in and out of the house.

#10 avarakin

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Posted 11 March 2011 - 01:14 AM

I dont remember exactly what was the issue with CG4.
I drag the entire imaging setup as one piece, comprised of LXD75, 5" reflector, netbook, DSLR:

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