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raf2020

PHD vs standard HEQ5 Pro and SynScan tracking

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Hello Guys,

Finally after 2 months of reading, watching, analyzing digging I have chosen and set up my first rig (almost as mount is still in delivery). As till now I have focused more on what should I pick rather than how to operate it, I need to double check few things that in theory I know answers, but as this is just an theory without practical experience yet I preferer to ask while waiting for mount:

Why I should use EQDIR and PHD tracking instead of just polar alignment and SynScan? It is so huge difference on accuracy or more like preference?

Double checking it because if I would go with standard tracking and use external battery I would avoid a lot of hassle with cabling from backyard to my pc in living room (somehow I don't like idea to keep laptop outside in plastic container considering seaside, island weather).

Cheers,

Raf

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Hi Raf,

Guiding with PHD 2 using EQDIR will mean that your stars in your images will be even clearer than if your were to just rely on the tracking of the HEQ5 Synscan tracking. There is going to be periodic error in the movement of the HEQ5 and the guiding in PHD2 will counter act this error. This link explains it well Mount Periodic Error

HTH

Grant

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Depends what you are planning on doing with the scope.

If you are visual only then there's no need for EQDIR and PHD2 and the Synscan handset is all you need.  A rough polar alignment should be enough to keep objects in the eyepice field of view.

If you are planning on imaging then, depending on what scale, the mounts tracking accuracy probably won't be accurate enough. I started with an unguided EQ5 and did get some usable images, but moved on to guiding.  

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Your answers have gave me full picture now. Thank you @Grant Fribbens and @almcl. My plan is DSO with long exposures on DSLR. But it's possible that I will start from observations just to learn how to do polar alignment, set home position (sic! this looks scary as per yt tutorials) and in general set up everything properly. Obviously pc tracking seems to be a way more suitable and accurate but I have no idea yet how to resolve cabling so that's why probably I will start with SynScan to check what I can get, then eventually I will move to PHD2.

You think I can plug all usb's to one hub? Camera, guide camera and EQMOD?

Btw. I have spotted that guide cam besides usb port has also st4 port to plug it to mount (in this case ZWO ASI 120MM Mini). I assume it is not necessary? But I am curious how it suppose to work?

Thanks,

Raf

 

Edited by raf2020

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As @almcl says, if you're not intending to do astrophotography then you don't need either, but it you are, then some guiding software will be required to correct the mechanical / alignment errors present in nearly every mount. PHD2 is the standard free software to do that and so you will need to use a PC. EQMOD is a nice to have, but isn't necessary if you use the handcontroller.

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1 hour ago, raf2020 said:

Your answers have gave me full picture now. Thank you guys. My plan is DSO with long exposures on DSLR. But it's possible that I will start from observations just to learn how to do polar alignment, set home position (sic! this looks scary as per yt tutorials) and in general set up everything properly. Obviously pc tracking seems to be a way more suitable and accurate but I have no idea yet how to resolve cabling so that's why probably I will start with SynScan to check what I can get, then eventually I will move to PHD2.

You think I can plug all usb's to one hub? Camera, guide camera and EQMOD?

Btw. I have spotted that guide cam besides usb port has also st4 port to plug it to mount (in this case ZWO ASI 120MM Mini). I assume it is not necessary? But I am curious how it suppose to work?

Thanks,

Raf

 

I have an EQ5 mount and plug the guide camera, DSLR, two dew heaters and the EQDIR cable into a 4 port powered USB hub I mounted on one of the tripod legs. I then have the USB hub connected to an active USB cable running into the house through a window and set up my laptop inside. The only other connection I need is power for the mount & USB hub, in my case I use an external extension cable so the connections are protected from the dew, others use 12v batteries or a power pack.

You can also get a USB to CAT5 connection for longer runs if your PC isn't close to where you put the mount. ;)

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1 hour ago, raf2020 said:

 Btw. I have spotted that guide cam besides usb port has also st4 port to plug it to mount (in this case ZWO ASI 120MM Mini). I assume it is not necessary? But I am curious how it suppose to work?

Thanks,

Raf

 

You can control the mount corrections generated by PHD2 via the USB connection to the guide camera and an ST4 connection between the camera and the mount, but it is better to control the mount corrections with a direct USB connection to the mount / handcontroller.

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@Budgie, @Seelive thank you both! This usb hub could be a solution plus I can mod ac adapter cable by extending it quite easily, so my balcony doors probably will close with 2 tinny cables going through (what was my biggest concern).

 

btw. in case I will use phd2+eqdir+tracking cam and wireless shutter release what is the reason to plug dslr through hdmi/usb to pc?

Edited by raf2020
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1 hour ago, raf2020 said:

btw. in case I will use phd2+eqdir+tracking cam and wireless shutter release what is the reason to plug dslr through hdmi/usb to pc?

I use software called Astro Photography Tool to run the DSLR on the laptop. This software will take the images at any ISO and exposure time you specify in the plan (no need to run outside and change the camera settings :D ). It has tools built in which can find and align the scope to your target with the a tool called "Plate Solving". This is where you take an image and it searches a database to find the location of stars in the image so it knows where it's looking, then you tell it what target you want to image and it will slew the mount to that target, taken another image, plate solve again until the target is in the centre of the frame.

It also has tools to assist with focusing and other handy tasks like talking to PHD2 when Dithering between images. You can download for free or pay a small donation to assist with development. ;) 

Edited by Budgie1
Typo
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I've only ever used USB for my 2000D, I think the HDMI is for sending video to another device, rather then controlling the camera. Just guessing though as I've not looked into it. ;)

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Sound good. Thank you!

edit:

@Budgie1 I have one more question. Does your usb hub need ac adapter to handle all those devices or not?

Edited by raf2020

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My USB hub is powered and I'm going to add a USB charging hub on to the extension lead, just for the dew heaters, just to be on the safe side as download from the camera takes a while, although I am only using USB2 connections on the laptop.

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1 hour ago, Budgie1 said:

My USB hub is powered and I'm going to add a USB charging hub on to the extension lead, just for the dew heaters, just to be on the safe side as download from the camera takes a while, although I am only using USB2 connections on the laptop.

This makes things a bit complicated for me. Or maybe I will be able to find extension cord with very thin cable to let it go through balcony doors and to be able to close it somehow. Or I will buy 2 x 10m ac adapter tiny extension cords plus 10m usb as I doubt it there is any 10m power extension cord with tiny cable. Thank you. 

Edited by raf2020

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