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CCD vs. DSLR – A New Learning Curve

CCD Camera vs. DSLR for astrophotography
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Like many of you, I love shooting astrophotography with my DSLR.  I control my Canon Rebel T3i with BackyardEOS to capture deep-sky objects through my telescope.  Then, the real fun begins by processing the images in DeepSkyStacker and Adobe Photoshop.

This method has worked for me for years, and there is lots of room to expand my astrophotography skills using this setup.  I favor this system because it is beginner friendly, and it’s where I can help others get started.

ZWO ASI071MC-COOL CMOS Camera

However, I couldn’t turn down an opportunity to try out the new ASI071MC-Cool for the first time.  Let’s talk CCD vs. DSLR Astrophotography, more below:

Spring Equinox

The warmer, longer days have returned as we are now officially in Spring!  The Spring Equinox occurred on March 20th here in the Northern Hemisphere, which means earlier sunrises and later sunsets.  I must admit, I am looking forward to the milder nights sitting at the telescope without the numb fingers.

The Big Dipper in Spring

The Big Dipper in Ursa Major – Early Spring 2016

Despite fewer hours of overall darkness at night, the Spring imaging window works much better with my schedule.  I can now get home from work at a reasonable hour (6:00 – 6:30pm), have dinner, walk Rudy, and be right on time for dusk to start setting up my equipment.

Visual Observing While Imaging

Historically, this time of year generally provides less cloud-cover than in the winter.  “April showers bring May flowers”. Regardless of how the old saying goes, I always seem to get lots of imaging time during the month of April.

binoculars for stargazing

Even better, I can actually enjoy my time outside rather than setting everything up and running inside to monitor Team Viewer.  The nights that drop below -10 degrees celsius are over.  I like to set up a zero-gravity chair and scan the sky with my 15 x 70 Celestron SkyMaster Binoculars.

With the camera collecting data through the telescope in the background, I just turn on some classic rock and get lost in the constellations.  Truly magical.

AstroBackyard is about the enjoyment of astrophotography as a hobby.  It’s about the desire to keep improve your images, and loving every step along the way.

New CCD Astrophotography Camera

The ZWO ASI071MC-Cool (Color) actually uses a color CMOS sensor (The same one used in the Nikon D7000) and was generously loaned to me from my friends over at Ontario Telescope & Accessories.

ASI071 Camera

Talk about information overload!  I have always shot astrophotography with a DSLR camera, and CCD imaging is completely new to me.

Since receiving the ASI071 last week, I have learned a wealth of knowledge on the subject thanks to fans of the AstroBackyard Facebook page, and helpful astrophotographers on Cloudy Nights.

One of the early setbacks was not knowing which Bayer pattern to use when stacking the .FIT files in DeepSkyStacker.  I’ll save you the trouble and tell you that it is Generic RGGB!

I was also advised to use (among other things) a UV filter when imaging with this camera which, unfortunately, I do not have.

Furthermore, using flat calibration frames is extremely important to properly calibrate the images in post-processing.  They are important for DSLR astrophotography too, but I found the new process of taking flats using Sequence Generator Pro to be a challenge my first time through.

ZWO ASI071MC-Cool (Color)

Sensor: Sony IMX071
Type: APS-C sized CMOS
Resolution: 16.2 MP (4928 x 3264 pixels)
Cooling: Regulated Two-Stage Tec (-40)

 

ZWO ASI071MC-Cool (Color)

Being the first CCD style camera I’ve ever used, my review is of CCD cameras in general, as opposed to this specific model.  I have no past CCD camera experiences to compare it to.

Currently, there are only a handful of early reviews of the ASI071-MC-Cool online, from more experienced CCD imagers than I.  A simple search of the camera model on Astrobin can give you some great examples of the capabilities of the ASI071.

What I can tell you from my personal experiences with the camera is that the ASI071 is impressive in terms of design and build quality.

The included accessories, documentation, and software from ZWO were very helpful for someone wanted to get started right away.  I’ll show you my early astrophotography results below.

Early Thoughts from a CCD Newb

So many questions, so many new terms, I felt like I was starting over.  With a CCD camera, you can forget about live-view focusing using the camera screen.  How about reviewing the image you just shot?  The camera doesn’t even have a screen!  Not to mention the new software required to run the camera, and process the new file format: .FIT

This is just the beginning.  A CCD camera is a specialized breed, capable of documenting scientific-grade data.  The advanced features like cooling to -40 degrees and full control of the gain and offset are why professional astrophotographers shoot narrowband CCD.

Some new software I’ve installed:




So far, Sequence Generator Pro has been rather enjoyable to use.  I was able to enter in my current equipment configuration and save it as an Equipment Profile, that I can select for each imaging session.  It was easy to integrate with PHD 2 Guiding, and provides a live graph with dithering options.

Testing the different sensitivity settings on the ASI071MC-Cool camera was a learning experience, one that took multiple imaging sessions to understand.  Thankfully the straight-forward controls of SGP allowed me to make changes and review my results quite painlessly.  The built in image preview and histogram made the process feel familiar.

I will note, however, that the live-view camera mode (for focus and framing purposes) seemed a little sluggish.  The 1-2 second delay in the video feed made making minor adjustments to focus a little aggravating.  I preferred to use SharpCap for this step, as it was much more responsive.

I’ll leave my early experiences using PixInsight for another post.  I am using 45-day trial versions of both SGP and PixInsight.  This option worked well for me, as I will only have the ASI for about the same period of time!

Early Imaging Results with the ASI071

I have to first say that there are a number of reasons why this image below is not a fair example of this cameras’ potential.  The photo below could have been improved by:

  • Integrating More Exposure Time
  • Using the Cooling Function of the Camera
  • Using Flats
  • Using a UV or LP filter
  • Shooting during New Moon

I don’t like to leave my reports without at least one photo.  So have a look at M81 and M82 with about 1.5 total hours total integrated exposure time from the backyard.  This was my test subject for this new process, and needs lots of work!  I’ll continue to capture more time on this target until I return the camera to OTA.

ASI071 example image

M81 and M82 using the ASI071MC-Cool Camera

The image was cropped over 50% to bypass the horrible gradient that dominated all sides of the image frame.  Again, this photo is for educational purposes only!  My goal is to produce an image using at least 4 hours worth of good data, using quality flat frames.

 

UPDATE: March 24, 2017

Click here for the latest version of M81 M82 (2+ Hours Exposure)

CCD vs. DSLR

Time will tell whether I ever fully transition to CCD imaging, or continue to push my deep-sky DSLR imaging to the limits.

I am very protective of my passion for astrophotography, and carefully monitor the emotions that are associated with my endeavors.  To sway too far away from the type of experience I enjoy most would be a miss-step at this stage.

I say this not to be overdramatic, but to share this insight from someone who lives and breathes DSLR astrophotography.  With that being said, many of the frustrations that come with learning new hardware ease over time, and become enjoyable.  I’ve already enjoyed some small victories with the ASI071MC camera and am having a lot of fun.

AstroBackyard YouTube Video:

I feel for beginner DSLR astrophotographers learning the ropes.  Starting with a completely new camera, software and imaging process has humbled me.  Perhaps I forgot what it felt like to be a beginner.  Pushing through the learning curve and enjoying the small victories along the way is what got me here.  It’s time to take my own advice!

A If nothing else, this experience will give me a whole new appreciation for my DSLR.  Until next time, clear skies!

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This Post Has 4 Comments

  1. Allan K says:

    Hi Trevor,
    I’ve enjoyed your videos as i start to look into astrophotography myself. Lots to learn and lots of time involved.
    Can you tell me the purpose of cooling the camera to -40c and how does it do this? It looks too small to have any sort of cooling abilities? OR am i missing someting here with the terminology of cooling?

    Thanks
    Allan
    Scotland, UK

    • Trevor says:

      Hi Allan, thank you! The cooling reduces the amount of thermal noise in the recorded data. I was used to a lot of noise with my DSLR, especially on a hot summer night where the sensor would rise to over 30 degrees C!

      The ASI071 has a two-stage TEC system that’s purpose is solely for producing images with low noise. It really becomes evident once you start stretching the data in post-processing.

      Clear skies!

  2. HI Trevor: being the owner of a T3ia and dealing with noise i decide to make my own DSLR cooler based on Martin P idea…when done it should cool the T3i down to about 10-15C below ambient temp. Its comprised of a 12706 TEC cooler and a TEC controller
    will be glad to show you the final product when done…this cooler bought professionally are going for 1800$ UK and im making mine for under 120$ CAD…
    I live not far from London Ontario (Tilbury) and cant wait to test this cooler this summer.
    My T3i can run as high as 40C on some nights.
    Mitch

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