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Autoguiding with Planets

08 Jan, 2019 12:30
Good morning,

In order to improve the quality of my planetary shots, I was going to try autoguiding with PHD.  Has anyone tried this with planetary shots?  Does it even work?  I was concerned because my planetary scope has a fairly large focal length (1540), and I often use a 2x barlow, and I wonder how much good guiding will do at that level of magnification.

Any thoughts or experience?
08 Jan, 2019 12:40
I do not think that this will make sense. During planetary imaging a single frame has low integration times (like 8 ms or something). Autoguiding will not improve images taken with an integration time that low. Most guiding setups send corrections in intervals of 1-6 seconds to your mount.
08 Jan, 2019 13:00
I guess that's my question, at that Focal length, can PHD work fast enough, and will my 50mm guide scope have the resolution to keep the planet centered in the frame?

The more I think about it the more I am doubting that it will work. smile
08 Jan, 2019 14:09
I dont think that this will work. The seeing is far more problematic than the small deviation from the tracking within that 8 ms. And you cant use an autoguider to avoid seeing-problems. Man, that would be great :-)
Edited 08 Jan, 2019 14:16
08 Jan, 2019 14:50
Michael T.
And you cant use an autoguider to avoid seeing-problems. Man, that would be great :-)

What we need is an adaptive mirror and a laser like the VLT… When do you suppose those will be on the amateur market?  Oh well, it was nice to kick the idea around…
08 Jan, 2019 15:39
I would love to own this really great solution, but i assume that the pricing is somewhat too high for my astro budget :-)
Edited 08 Jan, 2019 15:43
09 Jan, 2019 01:01
Normally when I have taken planetary shots with my 1250mm and barlows, I made a movie then processed it using Pipp, AS!3 and or Registax6.  My understanding is that due to the waves in the atmosphere, this method gives you the best chance of capturing several clear shots, and then those are stacked.  I think I read about it called "lucky imaging"  I had some nice shots for my equipment
09 Jan, 2019 03:03
Adaptive Optics isnt that expensive for amateur astronomers.

With my ZWo camera I use Firecapture and simply select Auto align and the planet just sits still (apart from translation distortions of seeing).  Thats what you are really wanting.  I am using 3000mm focal length Meade12inACF and 2x barlow, on a well polar aligned Titan mount. The postprocessing is faciltitated then. Some guiding corrections are then applied during liveview capture.

09 Jan, 2019 07:37
Didn't know that. Amazing. This thing is on my wishlist now :-)

[Edit]: After doing some research and reading reviews, this thing remains on my wishlist, but at the bottom of it. I have to check if it really fits both my approach and my setup.
Edited 09 Jan, 2019 08:41
21 Feb, 2019 02:27
Glad you asked, I am just now starting to dabble with planetary imaging and the thought of guiding to keep the subject from drifting has been on my mind. So it seems to just "chase" the subject via the mount controller to keep up with any drift is the way to go then. Thank you all. smile
21 Feb, 2019 04:42
My five cents: I would suggest to invest into polar allignment (the cheapest way  - to use Polar Scope Align App for Iphone or similar, helps a lot). With good polar allignment you do not really need even PIPPsmile
09 Mar, 2019 21:54
Yes. You can get it polar aligned close enough with a polar scope  or other methods for planetary. A little known secret is that a small amount of drift can be beneficial with planetary, assuming you're using high frame rate camera. Let's say  for example, you have dust spots on the sensor. If the planet was perfectly centered, that dust spot would  be concentrated on that same spot on every frame. But as it slowly moves, you get a better random mix of pixels. You also get a better random mix of hot and cold pixels. Otherwise the hot pixels (image noise) are also concentrated in the same spot or region of the image on every frame. A very small amount of drift is not a bad thing at all. It does'nt have to be perfect with planetary.
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