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Orion Sirius - Hypertune?

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#1 Dann-Oh

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Posted 16 May 2019 - 12:51 AM

Could any of you tell me if there is a way to hyper tune an Orion Sirius EQ-G?

 

I am imaging on my Sony A7iii (DSLM) and Sigma 150-600mm at 600mm, this is basically a 95mm refactor (to be clear the focal length is 600mm and the aperture is 95mm).  The image below is M13 captured with 31 exposures of 120sec I am getting trailing (I think I used 25 images in the stack).  The camera + adapter + lens weigh 6.13lbs.  I dont think the weight of the imaging rig is the problem here.  I dont want to say I have "nailed" polar alignment but I have been getting better at it each time.  Any other advice is much appreciated.

 

Also ignore the red circle that is NGC 6702 or is it 6207, I cant remember right now. 

 

14azwc8.jpg



#2 Jim Waters

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Posted 16 May 2019 - 12:57 AM

Check out this 

https://www.deepspac...rt=0&per_page=0



#3 Tapio

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Posted 16 May 2019 - 01:31 AM

I think you are doing pretty good if you are getting 2min exposures (almost all useable) with 600mm fl and no autoguiding.

With the price of hypertuning I bet you could add autoguiding gear too. I know camera optics is more trickier but can be done.



#4 Spoonsize

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Posted 16 May 2019 - 06:19 AM

Check out this
https://www.deepspac...rt=0&per_page=0



Not sure why they do not sell a diy kit for the Sirius mount.

#5 Astrodave

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Posted 16 May 2019 - 07:08 AM

I agree. If you are getting 2 minutes unguided at 600mm then you are doing well. Save the money for a mini guiding solution.



#6 Phil Sherman

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Posted 16 May 2019 - 09:22 AM

From my recollections from when I was imaging using a Sirius mount, a two minute exposure should have some some trailing caused by periodic error. Hypertuning can improve this but won't eliminate it. If you're running your mount using EQMOD from the computer, you could get an inexpensive eyepiece webcam that's compatible with PHD2 and use that to generate a PEC curve. EQMOD can add this curve into the computer's control signals to the mount using "pulse guide". The only restriction this adds to your using the mount is that you must always park the mount before powering it off to maintain the PEC synchronization with the gear train.

 

At some future time when you get a guide scope, you can use the webcam as a guide camera. Astro cameras that do this are the QHY5II and similar cameras. These are frequently called "solar system imagers". I've also guided using a previously retired Meade DSI I mono camera.

 

Polar alignment is critical for unguided imaging. You can drift align your mount using your camera by taking 70 second exposures at the standard drift alignment points. With the slew rate set to 1x sidereal, track for 5 seconds, slew E for 30 seconds then slew W for 35 seconds. If you're perfectly polar aligned, you'll see stars with a tail that passes back through the star. Polar misalignment shows up as a V shaped tail that misses the star. Adjust the polar alignment and repeat until you're satisfied with the alignment.



#7 EFT

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Posted 16 May 2019 - 12:16 PM

Not sure why they do not sell a diy kit for the Sirius mount.

Because the mount is fairly uncommon so demand for a kit is very low.



#8 EFT

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Posted 16 May 2019 - 12:19 PM

The Sirius mount is intended to be a guided imaging mount.  Two minutes unguided is about the most you can expect to do unguided, and then only with a fast system like you are using.  At this point, you really need to try guiding first before going any further.



#9 Spoonsize

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Posted 17 May 2019 - 03:37 PM

You could switch to belt drives easily enough.
http://www.rowanastr.../productsa1.htm


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