FEATURED BACKYARD ASTONOMER
Rob Musquetier from the Netherlands is EAPODs first Featured Backyard Astronomer. He started astrophotography in 2014 and here you can read about his personal journey towards creating the perfect astronomy picture. All endorsements for equipment and software are Rob’s own and are not to be associated with EAPOD.
A long, long time ago…
When I was a little boy I got my hands on the book ‘Sterrenkunde’ (‘Astronomy’) by Piet Smulders about the wonders of the Universe. I was mesmerized by all the beautiful images of planets, the sun, nebulae and galaxies as I read this little gem again and again. A couple of years later I became interested in technology and in particular the first primitive computers (mid-1980’s) and electronics. My father was an electrical engineer at Philips Breda so I grew up surrounded by resistors, capacitors and transistors and at home we were oftentimes the first to have the latest electronic gadgets. Unfortunately I never really actively pursued astronomy at a younger age …
40 years went by and in November 2014 I went to see the movie Interstellar; I was very impressed by the footage in this movie and it inspired me to also do “something” with astronomy. After some deliberation I purchased a telescope: the Celestron 6SE, a 150mm reflector telescope with a focal length of 1500mm (F10). Once the first clear evening presented itself, this setup, residing in my backyard in beautiful Limmen (near Alkmaar, NL), was put to work so I could finally admire the planets, stars, galaxies and nebulae with my own eyes!
However…I was quite disappointed …
Stars were no more than little white dots, planets were small little balls, galaxies were faint spots and the Orion Nebula M42, which ought to be mightily impressive, was just a white smudge. Was this all there was to see? On the Internet, on the Dutch Astroforum, it was confirmed that this indeed is what it looks like through a telescope.
Only the moon really met my high visual expectations. I enjoyed seeing the gorgeous endless number of craters and wide dusty plains! However I longed for color and spectacular pictures so I decided to move on from observation to photography. And it seemed bigger telescopes capture more light so the bigger the better!
My first go at astrophotography was with the 6SE combined with my Canon 60D, which was mounted behind the telescope with the sensor in focus.
I soon discovered I had two big problems: the mount-tripod was not stable enough and it was too wind-sensitive. Also I found an Azimuth setup is not really suited for astrophotography. Short exposures are possible but when exposing longer than 15 seconds, stars become little lines because the telescope is not compensating for earth’s rotation. After some research I found out I needed a mount that was capable of exactly that: an equatorial mount!
It wasn’t long before I had my hands on a used Skywatcher EQ6. I also bought some steel and concrete to build a stable mounting pier in my backyard. I determined the best place in my garden, dug a hole of 60 x 60 x 60 cm and filled it with 45 bags of concrete.
I recently attended a welding course (which I wanted to do for a long time), purchased a welder and then built a proper pier. The EQ6 was easily attached with an adapter plate.
One of the big advantages of a fixed setup is you only have to align the system with Polaris once. After that it the system is on continuous stand-by and can be used immediately on demand.
“Bigger is Better”
As said: “bigger is better”, so I bought a 280 / 2800mm F10 Celestron C11 Edge HD. This telescope is made especially for astrophotography as it has a built-in corrector / flattener, so more photons would reach the sensitive camera sensor of the 6SE. I was unaware at that time that using this telescope actually made astrophotography more difficult, but more on that later.
Around this time my pier was finished and I decided to build an observatory with some office-space around it. This made astrophotographing much more comfortable (the office-space is heated and isolated from the observatory). Another big advantage was that I didn’t need to remove the equipment from the pier any longer as I would just close the roof during bad weather. This really improved circumstances a lot and made astrophotographing much easier as well.
the reason photographing with the C11 Edge turned out to be rather difficult is because it is an F10 system. One needs a very accurate mount and a lot of patience in order for this to work! Looking back on things I wish I would have picked an 80/480mm (F6) telescope back then. A much more sensitive telescope, so faster and a lot less prone to inaccuracy of the mount.
Being somewhat naive and stubborn I nevertheless accepted the challenge and I was actually able to get some decent results.
I had quite some problems in the beginning, for example it turned out the USB-ports of my laptop were not working correctly and interfered with the connected equipment.
Furthermore I found out, to get better results, I needed to start auto-guiding. Auto-guiding is the process of having another (small) camera look through the telescope (in my case using a prism) and have a program called Push Here Dummy 2 (PHD2) accurately track a star in the image. PHD2 then sends corrections to the mount to get even better tracking results than what the mount itself is capable of. This comes with challenges of its own, but after some time I was able to track an object with my F10 telescope mounted on the EQ6 within +/- 3 arc seconds, which I think is actually quite acceptable for a beginner!
Because it kept being quite hard to get good results with the C11 Edge HD, I decided to buy a used TS 910/130mm APO refractor. This is an F7 telescope, so the required exposure times were a lot less than the C11. I was now able to gather more data during a session, which improved the quality of my images.
I also had to improve focusing. Focusing is pretty difficult: it is hard to see what’s going on on the camera but is has a tremendous influence on the final result. It wasn’t before long I learned to focus with a Bathinov filter. This filter makes finding optimal focus a lot easier, especially combined with the live-view function of my Canon 60D. I also learned to focus using BackyardEOS, which works quite good as well.
However, it wasn’t until I added an autofocus-unit to my system that things really improved! To accomplish this I attached a stepping-motor on the focus button and controlled it with an Arduino board and Easydriver (my experience with electronics and programming really helped here). I was now able to auto-focus using the Sequence Generator Pro software. During the night temperature changes make the telescope expand and/or shrinks a little which really messes with the initial focus. Using this software together with a temperature sensor, this is then compensated for.
Now the quality of my images was getting really good!
Need. More. Equipment.
It was then when I realized my Canon 60D was now the limiting factor. Its color-matrix needed long exposure times which is not something you want when you are living in a climate which doesn’t have a lot of clear nights (and I should add I am also somewhat impatient).
Two measures were taken to compensate for this: I bought a 0.8x reducer which effectively turned the F7 in an F5.6 telescope and I bought a CCD-camera, a used ATIK 383L+ mono 8 Megapixel, for a good price. Now we are talking!
It now only took a few hours to collect the same amount data, which at first took me several nights. And the quality of my images now really increased significantly!
The 383L+, being a monochrome camera, now meant I had to use color filters (Luminance, Red, Green, Blue, Hydrogen (Ha), Oxygen (OIII) and Sulphur (SII)) which I installed in an ATIK 36mm filterwheel.
In the meantime I also bought a 254/1016 F4 Newton telescope and a 80/480 F6 telescope and replaced my EQ6 for a Skywatcher EQ8 (which I then also attached to my pier). All three telescopes are now mounted together and tracking is within 1.5 arc seconds (sometimes even 1 arc second on nights with excellent seeing)!
Processing & Editing
Another important aspect about astrophotographing is the processing and editing of the data. After some experimenting with different programs I ended up using PixInsight. This software is designed to be used for editing astrophoto’s.
It has many features and really allows you to get the maximum out of your data. It can be quite overwhelming at times, so I still need to learn a lot about it. I also am learning to use Photoshop, because I believe the combination of PixInsight and Photoshop really works like a charm when it comes to astrophotography!
I recently sold the ATIK camera to buy a 16 Megapixel ZWO ASI 1600mm – Cool en I expect this will further increase the quality of the results due to the lower noise-levels. The preliminary result are very promising!
Astrophotography is a wonderful, multi-dimensional and -disciplinary hobby which will -without any doubt- keep me interested for many years to come. I am looking forward to making and publishing many more images of our beautiful universe!
If you’d like to be the next Feautured Backyard Astronomer, send us your story and [email protected] (you have to be a European citizen to qualify).