Who has not yet seen the most famous of the Hubble Space Telescope's photos, titled "Pillars of Creation"? Most likely, not too many people.
The original "Pillars of Creation" photo was published in 1995, and has ever since been featured in the media, on T-shirts, mugs and literally every merchandise imaginable.
The object itself is a series of columns of dense gas - mostly Hydrogen - in the process of creating new stars - hence the name of the photo! These clouds of Hydrogen are located within the Eagle Nebula (M16), a popular object within the summer Milky Way.
An interesting phenomenon of the photo itself is the "missing" squares in the top right - which are caused by the way Hubble's wide angle camera is constructed - the part recording this region of the image has a magnified view and therefore cannot be shown together with the rest of the photo.
Thanks to the original shot, this night sky object became well-known to the general public, and therefore it is no wonder that the "new and improved" version released twenty years later in 2015 also drew tons of attention among science enthusiasts, professional and amateur astronomers as well as everyone else really.
This time, the Hubble used its upgraded camera with a wider field of view and higher resolution. Once again, the photo amazed viewers all over the world.
In the twenty years that passed, amateur telescopes and astronomical imaging devices became more accessible and widespread, and the photo inspired many astrophotographers to have a go at this target.
When I got my largest telescope ready for deep-sky imaging, it was clear that the Pillars of Creation would be my first object to image.
I took my Celestron C11 Edge HD to a semi-dark site for a weekend for the first tests. I knew it would take me about three nights to take this image, calculating a night's worth of shots per color (using filters for Hydrogen, Sulfur and Oxygen).
I spent the first night imaging and testing that my new focusing system was working and that my tracking mount was able to support the weight and the focal length with adequate accuracy. I spent about 4 hours doing 5-minute shots with my Hydrogen filter, and they looked just OK at the time.
The following day as I went through the images, I realized that while the stars are round, some of them appear rather large, and I attributed this to the fact that while the autoguiding system of the mount was performing the appropriate corrections, they were not accurate enough to keep the stars small.
As such, I decided to just discard all the images from the first night and spend my final night under the dark sky re-taking the shots, this time using 1-minute subs. This obviously resulted in hundreds of images which takes a lot longer to process, but in turn, I feel more comfortable throwing some away, and there's a lower chance of having an issue within a frame.
I ended up using 175 60-second shots and I was quite happy with the outcome.
I knew I would have to finish the other two filters from my urban-suburban, relatively light-polluted home, but I figured it would be doable as I was using narrowband filters.
I had to wait a long time until I had two more nights of clear skies, and I was very excited to finish the project.
Imaging with my large telescope, using the off-axis guiding system from home proved to be an almost impossible task, the guidance sensor struggled to see any stars to use as reference due to the light polution. As such, I ended up throwing away tons of frames both from the Oxygen and the Sulfur filter and I concluded I'd have to come up with a different guiding system for when I image from home.
Nonetheless, I was ecstatic when I finally got to process the color image. I ended up using a total of 175 minutes of Hydrogen, 192 minutes of Sulfur and 104 minutes of Oxygen.
I was also not able to get the rotation of the camera perfectly aligned with the original image, so the overlap of the images was suboptimal, to say the least.
I combined the different colors according to the classic Hubble palette (Sulfur for Red, Hydrogen for Green and Oxygen for Blue).
After fixing the color balance and applying the proper crop, I added back the Hydrogen layer as luminance - as this picture had the most data and was the smoothest, it helped even out the final image and added some extra detail.
Unfortunately I had forgotten to take a shot of the stars in color, so I was going to have just white stars, therefore I used the stars from the Hydrogen layer as well.
I am overall pleased with the end-product. With so many things that could have - and that have - gone wrong, this was my very first project shooting at 2800mm focal length and at F/10.
I have also learned a lot from this project, to summarize:
I cannot shoot at F/10 from my home, at least definitely not towards the South where I have the most light pollution
I should double-triple-quadruple check the orientation of the camera before shooting :)
I should not force ultra long exposures. Slow and steady wins the race - in this case, slow and many does!
In the meantime, I already ordered the 0.7x focal reducer for my system which to make my tube just under 2000mm - therefore it should be much more feasible to use it for deep sky. I'll be keeping the native 2800mm focal length for those few lucky nights when I am under dark skies.
And now, without further ado, my final image of the Pillars of Creation:
And a close-up to resemble the original field of view:
