New EQ3 Pro mount after Newstar alt/azi - quite the change!

[Jimmyborofan]

HI All,

This is my first post on this forum, I've been an amateur about 18 months and have slowly built up my kit from a (relatively) cheap Nexstar SLT through to my new EQ3 Pro, I am limited in skyspace as the mount and scope are quite hefty now and taking it around requires more planning.

So, that me and I have recently set up my mount with a 200x1000 reflector I am able to set everything up and with a lot of measuring, I've been mark out N.E.W.S Im learning how to cone correct and gradually I am getting closer and closer to v.long exposures.

The big problem is that I'm not sure if I have enough power going into the unit.

When I try to start alignment as soon as it tries to move two axis at once under full power it just cuts out for a moment. I'm using a 12V 2amp power supply but read somewhere that it is supposed to be 5 amps? The only power cable in the box was for plugging into a car.

I did a few manual tests trying to discover the optimum speed, which is Rate 6-7, its fast enough and it causes no noticeable drain. I can manage to align on occasion (EKOS wont connect if you're not aligned) and I have tried to set the Slew Speed through KStars INDI control panel, and set the autoguide speed to .25 but iot is still trying to slew to alignment at top speed.So, so far, no luck.

Can anyone help by giving me a point in the direction of how to change the alignment slew speed and if that is enough power and do I need 5 amps?

Many thanks for your help and now Im becoming a bit more serious, I hope to see you on here more

Jim

[Lady Fraktor]

Hello and welcome to the forums Jim, I assume the EQ-3 is a Skywatcher make.
With the newer EQ mounts people seem to be using 5A but unfortunately Skywatcher does not provide a lot of information in their manuals so I would encourage you to email Skywatcher and ask them directly.
You could also inquire from retailers such as Firstlight Optics or 365 Astronomy (both UK)

To change the slewing rate press the button marked rate, then a number between 1-9 (1 is slowest, 9 is fastest) the press enter.
Your slew rate should be changed.

Using a 200mm newtonian on a EQ-3 mount is a lot so I would not use use maximum slewing rates and I would be more concerned the effort of moving/ stopping that large scope may be why your mount is cutting the power.

[SkyHiker]

The weight of that reflector seems to be 8.75 kg while your mount has a limit of 5 kg for astrophotography and 7 kg for visual. So, you are slightly over the limit. Doing AP with it may be frustrating as the overweight leads to larger tracking errors than you will like. There are nice 61 to 81 mm refractors that would be fine though, something to think about.

About the power usage, I see that a 12V 5A power supply is recommended for Celestron mounts including the AVX that I have. If you have a car battery, see if that works better and if so, get a 12V 5A AC adapter.

I never have the problem that I can't slew when I am not aligned in Ekos using an OnStep controller. But when I use my AVX with Ekos, I have to first set the time date etcetera and go through some kind of alignment using the mount's controller, in orde for it to work. That sounds like how it works for you.

When slewing is a problem, the first thing to check is if your balance is right. Then, check if you need to loosen the worms. I went through lots of such problems myself with a G11S and an OnStep setup. In the end, the motors may be too small for the weight that you put on it. That 200 mm reflector is way too much for AP with an EQ-3 mount anyway so you should look for something smaller.

[Butterfly Maiden]

Hello Jim and welcome to the Forum.

[Jimmyborofan]

Lady Fraktor, SkyHiker, Butterfly Maiden Thank you for the welcome!

SkyHiker, Apologies, Yes its the skywatcher, I was thinking that this might have been the issue. the reason I bought it was I was hoping it would hold the 200. I will try the reduced speed, and slightly higher power supply before I think of changing the motors, Im a basic noob in AP, but Ive 'hobbied' with electronics for a while, looking at the designs for the motors in the drawings, a few larger stepper motors, belt, ratchets, cogs and an arduino may be the way forward. However I do have 130 reflector and a 90mm refractor, these two are very light and have had no issues on the Nexstar.

All it is, is that the images I can see through the 200.... wow! and I cannot wait to be able to set up my guide cameras...

Next thing is to convince the missus that a a mount bolted to the balcony floor is a good idea...

[SkyHiker]

SkyHiker, Apologies, Yes its the skywatcher, I was thinking that this might have been the issue. the reason I bought it was I was hoping it would hold the 200. I will try the reduced speed, and slightly higher power supply before I think of changing the motors, Im a basic noob in AP, but Ive 'hobbied' with electronics for a while, looking at the designs for the motors in the drawings, a few larger stepper motors, belt, ratchets, cogs and an arduino may be the way forward. However I do have 130 reflector and a 90mm refractor, these two are very light and have had no issues on the Nexstar.

Even those may be too much - think of 80 mm refractors or smaller. Here's a discussion about using EQ3 mounts for AP. Sorry to bring you the bad news but it's beest to know what you are up against. If AP is your main goal and you want to stay in the hobby, you will need a bigger mount.

All it is, is that the images I can see through the 200.... wow! and I cannot wait to be able to set up my guide cameras...

An autoguider will not help enough to make a typical EQ3 mount track accurately with that scope on it.

Next thing is to convince the missus that a a mount bolted to the balcony floor is a good idea...

Markers for the feet should be enough. There is no point in bolting it down, as the legs have so much flexure that the slightest push will throw the polar alignment off. I have an EQ3 mount myself, so I know. I was thinking about motorizing it for a portable AP setup but decided it was not worth the trouble.

The most important piece of equipment for AP is the mount, and the weight limits are usually important to observe. For example, I used an AVX for a 127 mm Apo and never got satisfying images. It was pushing the mount to its limits (slightly over). Meanwhile, go use your mount for visual and enjoy. I like my EQ3 with an 80 mm on it for visual, easy to grab and go.

[Richard]

yes for a big telescope like a 200 x 1000 one needs a big mount at least a EQ 5 for visual only , I had one and was just ok for visual but not great so sold the the OTA and replaced with a 150 Mak now great, but at least no shakes l that scope on a EQ 3 no

[seigell]

For whatever Mount you settle on, the Power Supply is a significant accessory. The Precision Motors driving the Mount have significant "Impulse Draw" requirements at the first instant of a Slew, so that the motors can overcome the Inertia of the combined mass of Scope and Imaging Gear and Counterweight and Mount. In the case of the EQ3, the spec'd 12V 5A is realistically necessary for the first fractions of a second before backing to a more reasonable current draw. (It is likely that your 12V 2A PS drops the Voltage significantly when encountering the initial draw of the motors.)

As you are an Electronics Hobbyist, consider undertaking a Design/Build Project for your Power Supply. A good power supply for AP Imaging should be Portable (battery-based) so that you can travel to a local Dark Site, and have sufficient capacity that an all-night Imaging Session under "Perfect Skies" isn't disrupted by a Low Power failure nor drain your Battery(s) to the point of Damage its Cells. As you assemble your AP Imaging Kit, you will find that you have additional Power Supply Requirements for the Guide Camera, the Imaging Computer, the Dew Heaters, and your Imaging Camera. A quality Battery Pack can be designed to address all these requirements and provide a few spare connectors for future needs. And a DIY project means that you can prioritize Size or Capacity or Connectivity, and add whatever Monitoring Gauges you wish.

[Bigzmey]

Looks like you are already in the good hands, so I would just say Welcome to TSS Jim!