Auto Guiding and Canon EOS Rebel SL1

It’s been a couple of weeks now since I got my Orion StarShoot Auto Guider and used it for a couple nights observing my favorite, the DumbBell Nebula.  And to be honest, kind of struggled in finding the optimal values for my scope. I attached it to the Celestron 50mm finderscope that came with the Celestron 11″ AVX Package. Only removed the rear lens and added the Blue Fireball T / T2 Male Thread to SCT Male & M48 (2″ Filter) Female Thread Adapter # T-07  and the fit was perfect.  A couple of adjustment on the primary lens to get the focus crystal clear.

Also my Canon EOS Rebel SL1 arrived.  I loved it because of it’s size and weight and also the features too.  It was perfect for the my setup since the Celestron AVX Mount can only handle 30lbs of load.  Making sure that I’m not overloading the mount as I know it will affect the quality of tracking.


Using PHD 2 with all the values totally alien to me, I wasn’t really able to get anything but lost most of my time reviewing the parameters.  I got an error about “star didn’t move enough” and with a lot of web search, I’m lucky that I’m not the only who struggled with it.

For a couple of nights, testing it, one by one getting the values right till finally I’m doing 2000 secs of exposure.

First here’s my setup

  • Celestron 11″
  • Advanced VX Mount
  • StarShoot AutoGuider attached on the 50mm finder scope
  • Celestron StarSense
  • Canon Rebel SL1
  • 1.25″ Orion SkyGlow Astrophotography Filter

Here’s what I used to have on PHD-2 which is giving me a really bad result

PHD2 Bad Value
PHD2 Bad Value

The Dumbbell Nebula with stars showing the “shotgun pattern” because of the error on RA and DEC on PHD-2.  On that image, I’m getting a Polar Alignment Error of 0.25′ (6px).  I thought it’s because my polar alignment is bad but ultimately it’s the combination of values and the selected guide star that make things worsts.  Here’s the link to see the full size of the image above so you can see the values set Full Size Image.  Below is a result of the PHD settings above where stars having trails.

Dumbbell Nebula
Dumbbell Nebula
  • Number of Image : 1
  • Exposure Length : 500 secs
  • ISO : 400
  • Censor Temperature : 28c
  • No post editing

And here’s the History Graph with the Star Profile when I got all those variables to an optimal value

PHD2 Good Value
PHD2 Good Value Full Image Size.

The Dumbbell Nebula after the optimal calibration

Dumbbell Nebula
Dumbbell Nebula Full Image Here
  • Number of Image : 1
  • Exposure Length : 519 secs
  • ISO : 800
  • Censor Temperature : 32c
  • With minor post editing using Adobe Lightroom

My final settings
Screen Shot 2014-09-02 at 8.43.05 PM

  •  Aggresssion – default is 100%, changed to 70% since this will cause the calculation to the stars current position affect the movement of the mount resulting in a double barrel shotgun pattern.
  • Hysteresis – the algorithm used for calculation, default is 10
  • Calibration Steps – played around with this an 2500 was the most optimal for my mount
  • Max Duration RA – 500 – default is 1000
  • Max Duration DEC – 500 – default is 1000

One of the best result of auto guiding

PHD2 Autoguiding
PHD2 Autoguiding Full Size


4 thoughts on “Auto Guiding and Canon EOS Rebel SL1”

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