Topics

Buying an EQ5

julianporter5@...
 

I’m going to buy an EQ5 upgrading from an EQ3-2.

I could buy secondhand but is there a risk that the mount is worn? Is it possible to damage the mount?

Am I better to buy a new mount?

Khalid Baheyeldin
 

On Mon, Dec 23, 2019 at 01:02 PM, <julianporter5@...> wrote:

I’m going to buy an EQ5 upgrading from an EQ3-2.

I could buy secondhand but is there a risk that the mount is worn? Is it possible to damage the mount?

Am I better to buy a new mount?

Howard pointed out the Meade LX70, which is even further discounted $199. Better than used.

Unless you can get the older Orion or Celestron branded made in Japan (by Vixen) Super Polaris
or Great Polaris, which will have lower periodic error.

Ivo
 

Im having similar dilema. More of a : is this a mount with enough quality in its parts to handle goto system with steppers? It looks fragile to me but i havent seen it in person. 
Thats why Im also on a lookout for older vixen polaris mounts. GP and Super polaris. I just lost a bid for a 30 years old superpolaris on ebay.

On Mon, 23 Dec 2019 at 19:02, <julianporter5@...> wrote:

I’m going to buy an EQ5 upgrading from an EQ3-2.

I could buy secondhand but is there a risk that the mount is worn? Is it possible to damage the mount?

Am I better to buy a new mount?

Joe
 

I initially had a used EQ-5 and it turned out that one of the bearings was siezed and a total loss. I found a used Vixen GP, took that apart and hypertuned it. Thankfully for me the parts from the EQ-5 were a perfect fit on the GP.
Having both mounts apart I’d really go with the GP if possible, i found mine used for $200.
There is simply no comparison between the two. The GP uses better machining and higher quality parts, no question about it.
Should you happen to buy either of these it’s an improvement over the EQ3.
If you find one be aware new parts are really hard to find. I have a donor mount and may be able to help out if needed. 





On Monday, December 23, 2019, 1:14 PM, Ivo <ibabarovic@...> wrote:

Im having similar dilema. More of a : is this a mount with enough quality in its parts to handle goto system with steppers? It looks fragile to me but i havent seen it in person. 
Thats why Im also on a lookout for older vixen polaris mounts. GP and Super polaris. I just lost a bid for a 30 years old superpolaris on ebay.

On Mon, 23 Dec 2019 at 19:02, <julianporter5@...> wrote:

I’m going to buy an EQ5 upgrading from an EQ3-2.

I could buy secondhand but is there a risk that the mount is worn? Is it possible to damage the mount?

Am I better to buy a new mount?

julianporter5@...
 

Shame the Meade scope isn’t available in Europe at that price.
I can see a new Eq5 at £275 but not much new better than that.

julianporter5@...
 
Edited

What is the quality like of a Bresser Mon2 eq Mount

I've seen a Vixen Great Polaris but the end of the declination worm gear shaft has sheared. This begs the question whether there is other damage to the gear. Where would I find a replacement worm gear?

Prasad
 
Edited

 
Vixen worm shaft extended on both sides and so, it may be broken only on one end. Since it is a Dec shaft you may still be able to use the mount. RA shaft damage may give you excessive PEC but Dec shaft damage is not consequential IMO.

Added during edit:
A Vixen GP mount is greatly superior in quality to Bresser (or any China made) mount. I have both Vixen GP & SP as well as Bresser EXOS2 and I am stating my experience. 
 
 
 

On Tuesday, December 24, 2019, 08:14:43 AM EST, julianporter5@... <julianporter5@...> wrote:
 
 

[Edited Message Follows]

What is the quality like of a Bresser Mon2 eq Mount

I've seen a Vixen Great Polaris but the end of the declination worm gear shaft has sheared. This begs the question whether there is other damage to the gear. Where would I find a replacement worm gear?

julianporter5@...
 

Are there any issues with reversing the worm gear in the housing to get the good end of the gear on the side I want it?

Joe
 

Here is a link for hyper-tuning: http://www.astronomyboy.com/cg5/Astronomy_Boy_CG-5.pdf
The CG5 and Vixen GP parts are interchangeable, but the Vixen parts are much better quality. Yes you could reposition that DEC gear so it would work, but you may have other issues.
the RA and DEC gears are interchangeable, but the idler housing runs around outside of that gear. If it’s deformed it will cause drag or worse, seize together. Mine was frozen and I tried everything to get it apart, including taking it to a machine shop where it broke completely. 
Eventually I used the CG-5 parts to repair a broken GP mount. I looked for parts for over 3 months before that. Forget about buying parts from Celestron........
The great people at Vixen did their best to help me out, but parts just aren’t available. Really fantastic and helpful people over there!
If you do buy it, and need parts let me know. I have a couple random parts that may help. I’d suggest just waiting for a complete working mount, they do come up from time to time.



George Cushing
 

I had one like that, I put in the oven @ 275°F for an hour and was able to pull it out. I use Softscrub to lap the parts. It's basically bicarb and soap. I like that it washes off easily. While stiff crown housings are a nuisance, unless they force the crown out of round they won't effect tracking as the housing is locked to the crown when tracking.

While organizing some parts I was looking at my box of Meade DS/ETX take offs and various worms from these mounts. Nearby on the shelf was a crown from a CG-5 that hadn't found it's way to the right parts box. I picked up to check how close the pitch and lead of the Meade worms were to the crown and was surprised to find they matched. So there's a possibility they can be used to replace bent and missing worms.

I wouldn't spend the extra money on a GP, As this mount and it's clones are limited to about a 20 pound (10Kg) payload for AP. A GP-DX might be worth waiting for with it's greater Payload.

Alexander Varakin
 

Julian,
What are you trying to do with your mount? Visual or AP? What kind of telescope do you want to use?
I converted my old LXD55 to onstep and it works ok with 9.25" SCT for visual, although the tripod is not very stable. 
LXD55 is very similar to EQ5 and the head alone would be less than $100.  The full mount with electronics is around $250.
Once you remove the electronics from it, there is not much left in terms of mechanics and they are fairly solid and can be maintained for a long time. It takes very little effort to take it apart once you know how to do it.

Alex

Joe
 

I can confirm that 20LBS is really too much for the mount. I’m at 18.8 lbs plus counterweight and it works ok, but a small tap on the tube and it takes a long time to settle down from the vibration. Using the remote with OnStep is a really big improvement from that standpoint. The original aluminum legs I have are biggest part of the problem. I’ll be upgrading the legs and/or this mount as soon as something comes available. Not to mention I’d like a refractor triplet... and a whole bunch of other stuff Santa forgot this year ;) 

julianporter5@...
 
Edited

On Wed, Dec 25, 2019 at 07:29 PM, Alexander Varakin wrote:
What are you trying to do with your mount? Visual or AP? What kind of telescope do you want to use?
 

I want to start on astrophotography and see how I get on capturing some nebulae.
The mechanics of my Eq3-2 are not good enough for it to be suitable. 

I discern from the advice above that I would do better getting a good used Vixen GP rather than an Eq5 (new or used). Better still to look for a Vixen GPDX. 

I’m only starting out so I’m not looking for the last word in quality. I’ve got a budget of £300 which would buy a new EQ5.

I’m using a Skywatcher 127 telescope at the moment. I would envisage something larger in the future. 

Khalid Baheyeldin
 

On Thu, Dec 26, 2019 at 02:37 AM, <julianporter5@...> wrote:

I want to start on astrophotography and see how I get on capturing some nebulae.
The mechanics of my Eq3-2 are not good enough for it to be suitable. 

I discern from the advice above that I would do better getting a good used Vixen GP rather than an Eq5 (new or used). Better still to look for a Vixen GPDX. 

I’m only starting out so I’m not looking for the last word in quality. I’ve got a budget of £300 which would buy a new EQ5.

I’m using a Skywatcher 127 telescope at the moment. I would envisage something larger in the future. 

There are two approaches to this: one aims to get it right from the start, the other is incremental.

I took the incremental route, and went through 4 mounts in about as many years.
They include:
- A mid 1980s Meade DS-10, which is a 10 inch Newtonian, with only an RA drive that runs on 110VAC. The optics were superb, but no Goto was a hinderance. It was also very bulky and heavy. I was able to take some great images with it, e.g. M8 (from a dark site), the Leo Triplet, and M42. All unguided and unprocessed (not guiding in the mount anyway). The camera was a Canon 650D DSLR.

Then I came across a Celestron C8, bought a 0.62X reducer, and used the same DSLR.

- A CG5 with the old iOptron GotoNova kit. The mechanics are so so, and the electronics were frustrating. Still, I was able to get good images with it, e.g. NGC 891 edge on, M33 and NGC 6946 Fireworks Galaxy ( from a dark site). All unguided.

- A Vixen GPDX with the Sky Sensor 2000 PC controller. The gear precision is much better. Here is M42 120 seconds unguided. I discovered OnStep and wanted to have a mount based on it.

- A Vixen SXD, which I converted to OnStep. Started with unguided images, with PEC and Compensated Tracking: M20, M13, M16, M17. Just before the cloud season, I started autoguiding, but only experimented with it a few times, so not fully experienced with it yet. But they eliminate the need for PEC (provided your mount has a low periodic error).

And if you get a bigger mount, it means that it will be heavier and harder to transport (whether that is from the house to the backyard, or from your house to a dark site). The GPDX is about the limit of what I can carry (with the tripod, minus the counterweight) with relative ease to the backyard. The same goes for the SXD. The DS-10 was a monster.

By experimenting, you find out what works for you and what does not, rather than hearing about it from forums and such. You also don't need to sink in a large budget from the start, only to find that the rig is overwhelming with lots of parts each with its own learning curve.

Alexander Varakin
 

Looks like Skywatcher 127 is Macsutov with ~1500mm FL.
For this scope, one needs a decent mount.
Taking images with CG5 class mount would be VERY challenging. 
Keep in mind that Macsutov might not be the best imaging scope. I have a friend who tried taking images with Mac and the star shapes were not great.
I suggest to step up and look for a bigger mount.
I have no idea about market for used mounts in UK, but in the US one can get the following mounts on the used market:
1. $300 for CGE with broken electronics. CGE is a beast, but it has probably the best price/performance ratio, given that spare parts are not available so folks are dumping them very cheap.
2. $500 for Losmandy GM8 without go to system. If you are lucky, you may get tripod and CW included for the same price. I have this mount for portable use and it is great.
3. $300 for Orion Atlas/EQ6 with broken electronics. Some older models of Atlas did not have goto and just had manual motors and now go pretty cheap. Atlas is a great mount, I had it for several years.
4. $700 for Losmandy G11 without go to system. If you are lucky, you may get tripod and CW included for the same price. My current mount is G11 which I bought for about $600 for head only.  It is a very good mount and allows me to take images with 10" RC. 

Of course, prices are very approximate and are based on the condition of the item and your luck.
I suggest to start watching local astro classifieds, hopefully, something will show up soon enough. 

Alex

Khalid Baheyeldin
 

On Thu, Dec 26, 2019 at 09:17 PM, Alexander Varakin wrote:
Looks like Skywatcher 127 is Macsutov with ~1500mm FL.
For this scope, one needs a decent mount.
Taking images with CG5 class mount would be VERY challenging. 
Alex is right. The longer the focal length, the more small errors are amplified.
I image at 1310 mm (C8 + reducer), with a Vixen mount with quality gears, and that is at the edge of what is practical.

Keep in mind that Macsutov might not be the best imaging scope. I have a friend who tried taking images with Mac and the star shapes were not great.
Another factor is the Maksutov is probably F/12, and therefore very dim for astrophotography, requiring double the exposure time of an F/6 scope.

Keep the Maksutov for planetary observation. It will be good for that.

I suggest to step up and look for a bigger mount.
Or, get a short focal length APO or ED refractor. Something that is 80mm or so, and 500mm or less. F/ratio of F/5 or F/6 should do the trick.

You will get very good results that way even with the CG5.

julianporter5@...
 

I have found a Vixen GP available at a reasonable price. Only thing is there is no polar scope. Does anyone know if I can use an Eq5 polar scope with it?

Joe
 

They use the same polar scope. I Have a spare should you need one.




On Thursday, January 2, 2020, 2:01 PM, julianporter5@... wrote:

I have found a Vixen GP available at a reasonable price. Only thing is there is no polar scope. Does anyone know if I can use an Eq5 polar scope with it?

Dave Schwartz
 

Polar scopes are highly overrated. Check out OnStep's RefinePA feature... you'll never use the polar scope again.

On 2020-01-02 3:20 p.m., Joe via Groups.Io wrote:
They use the same polar scope. I Have a spare should you need one.




On Thursday, January 2, 2020, 2:01 PM, julianporter5@... wrote:

I have found a Vixen GP available at a reasonable price. Only
thing is there is no polar scope. Does anyone know if I can use an
Eq5 polar scope with it?

Khalid Baheyeldin
 

On Thu, Jan 2, 2020 at 05:31 PM, Dave Schwartz wrote:
Polar scopes are highly overrated. Check out OnStep's RefinePA feature... you'll never use the polar scope again.
I second that.
Polar scopes are also very hard to collimate.

If you do a 3 star align, followed by the OnStep Refine PA, you will get very good results.
If you have plate solving and Sync to solved coordinates, the whole process is far less tedious.

Another approach you may want to try is using KStars Lite on your Android phone, go to the celestial turn on the equatorial grid, press the phone on a flat surface 90 degrees to the RA axis, and zoom in. Adjust the alt and az knobs until it is centered. The trick is finding a flat surface that the back of the phone would go on. For example, on an EQ5, if you remove the polar scope, you can press the back of the phone against where the scope should go, and the celestial pole of your hemisphere will appear. If you do it on the other end (where the cover should go on the north side), then use the opposite celestial pole.

I tried it indoors, and it should work, when the clouds go away (February or March?)