ArtCentrics.com

Introduction

Here we will cover the basics on optimal hardware setup for imaging Solar System Objects.

References

• A Guide to DSLR Planetary Imaging by Jerry Lodriguss - One of the best resources for Astrophotography.

• TimeAndDate.com: Distance, Brightness and Size of Planets - This link gives good information on when the planets are up, and the size of the planets at the given date.

• - High Resolution Lunar and Planetary Imaging Hints and Tricks

Imaging times

Reference: A Guide to DSLR Planetary Imaging: Planetary Rotation and Detail Smearing

When using lucky Imaging, time is limited due to the fact the object may be rotating.  Here is a summary of rule-of-thumb imaging time limits for video capture assuming 0.5 arcseconds of detail smearing allowance:

Barlow Lens

Reference: A Guide to DSLR Planetary Imaging: Sampling

First we need to determine the Optimal Magnification for our hardware.  We want to get the most detail possible given the seeing conditions, scope and camera capabilities  This is determined by the following variables:

• Imaging Scope Focal Ratio (Sfr)

• Imaging System Focal Ratio (Ifr)

• Camera pixel Size (Cps)

• Camera Sensor Dimensions

• Seeing Conditions - Scaled here as 5-7, where 5 is normal, 7 is exceptional

We start with the assumption that the Optimal Focal Ratio (Ofr) of the imaging system should be 5-7 times the camera pixel size based on seeing conditions (5 for average, 7 for exceptional), so we will go with 6 time the pixel size in these calculations.

Ofr = 6Cps

Assuming our camera and our scope are not easily changed, we cant change those variables, what we can do is change the Imaging System Focal Ratio by adding a Barlow lens if necessary to try to get to the Optimal Focal Ratio (Ofr), or use Eyepiece Projection.  Here we determine the appropriate Barlow Lens Magnification (Bx)

Bx = (5-7)Cps/Sfr

Here is what I have calculated for some hardware, where Barlow Magnification magnification is from good to excellent conditions (5-7):

Will it Fit?

References

• A Guide to DSLR Planetary Imaging: Planetary Rotation and Detail Smearing

• Astronomy Tools: Field of View Calculator

Now that we know the Optimal Magnification and have determined what Barlow lens we need, we need to determine if the image will fit on our sensor, and what wiggle room we have, because as we are capturing the image, things tend to drift.  First consideration is the size of the object you are imaging.  While the sun and moon stay the same size throughout the year, the planets vary based on how close they are to the earth.

Apparent Size of common objects in the solar system

Field of View