Backyard Astrophoto – Improvements in the Last 10 Years

When I first started astro-photography you had people like me who were just starting off and did it on the cheap with a webcam, a small newton telescope and basic mount, or you could fork out an astronomical amount of cash to get really specialized gear.

Below is a photo of Messier 101 the Pinwheel Galaxy taken last week with a $500 Skywatcher80ED telescope and Canon80D DSLR on an unguided mount.

Messier 101 - Pinwheel Galaxy
Messier 101 – Pinwheel Galaxy (Skywatcher 80ED and Canon 80D)

I agree that it’s not as fancy as some of the research grade setups or some other hobbyist out there, but it’s many times better than my first try in 2008 (below).

My results of Messier 101 in 2008

What has changed? Well for starters the optical quality of beginner and intermediate telescopes has dramatically improved, largely thanks to automated and computerized lens and mirror shaping and polishing. Yes they are made in China, but so are most carbon-fiber bikes and the latest smart-phones. As the process is automated, quality can be tightly controlled and the results are hard to beat. A quality image starts by being able to collect and focus light properly, and for $500 you can get some really descent optics.

Another great boost is improvements in camera sensors. DSLR became a go-to solution because it was a cheap way of getting a large sensor with low read noise and good sensitivity. Of course there are still monochrome specialized astro-gear available for backyard astronomers, but the one-shot color results of a DSLR are hard to match. DSLRs offer ease of use, compatibility with most software and are the biggest bang-for-your-dollar compared to specialized astro-cameras.

And the third major improvement in 10 years is computing power. A night imaging session can easily generate 1GB of RAW images that need to be processed. Transferring and storing data is now cheap, and software has followed in lock-step to handle the increase in image size and quantity. Registering and stacking software can easily handle at the pixel-level hundreds of images each with millions of pixels. Sure it might take 20 minutes to process 120 photos from the DSLR, but that is a far cry from the hours of computer crunching. If your parameters were wrong, you just wasted a hour….

So while light pollution is choking the stars out of the night sky, one easy way to gain access to the universe is through astro-photography. It’s now easier and cheaper than ever to get good results with a simple setup.

The Sun is Awfully Boring Right Now

Most of the world is self-isolating to reduce the spread of COVID-19, and we can’t even keep ourselves busy with daytime sunspot observations. The sun is completely free of any spots.  Below is an image taken on April 4th.

Sun on April 4, 2020 with no sunspots.

Skywatcher 80ED, Thousand Oaks Solarite filter, Canon 80D

So far this year we’ve had 70 days without sunspots, that is 74% of the days with no sunspots.  We are at the lowest part of the sun cycle, however things should change soon.

wolfjmms

Maybe by the fall we should have something a little more interesting to look at.

So you have a bunch of Moon shots in RAW. Now what?

UPDATED 07-Apr-2020: Cropping instead of reducing image size


The Moon should be your first target when you start off in astro-photography.  It’s easy to find, does not require dark skies and you don’t need specialized gear.

So now that you’ve found yourself will a bunch of RAW photos of the Moon you’re wondering what to do next.  You took them with the RAW setting right? All astro-photo need to be taken in RAW to conserve as much information as possible because all the processing is done at the pixel-level and you want to retain as much detail as possible.

Registax is a great software for Moon and planetary stacking.  Unfortunately I find it has two drawbacks:

  1. Cannot deal with .CR2 CANON RAW files
  2. Crashes or gives a memory fault when dealing with large images from DSLR.

Luckily there are ways around it… You must be wondering, why use Registax if it can’t deal with large RAW CANON files?  It’s because it can align and stack images by sub-dividing your image to address atmospheric turbulence and it has one of the best wavelet analysis tool to sharpen images.

Here is what you must do: convert your RAW files to 16-bit .TIF and reduce the image size (not just the filesize, but the number of pixels in the image).  I use Digital Photo Professional 4 that came with my CANON camera, it can be downloaded. For other camera brands or photo software should allow you to also convert RAW into TIF format.

There are two possible ways to reduce the image size:

1. Resize the image – this is the fastest and simplest

Highlight the desired RAW files and select File – Batch Process

DDP4 - Main window. Selecting the desired files

DDP4 – Main window. Selecting the desired files

In the Batch Process window select to save the files as 16-bit .TIF and ensure that you resize the images.  Normally 50% reduction will do the trick. In my case a reduction to 3000 x 2000 was sufficient.

DPP4 - Batch process window : Saving as .TIF and Resizing the images

DPP4 – Batch process window : Saving as .TIF and Resizing the images

Resizing will reduce the size of the Moon, and Registax has a better chance of dealing with alignment. It’s also a simple way to reduce noise and improve a less-than-perfect  focused image.

2. Alternatively : Cropping the image – more time consuming

If you don’t want to shrink the image, an alternative is to crop the image. With DPP4 it’s possible to apply the same crop setting to all the images, however it must be done one at a time.

First select one of the images and open the Tool palette.  Select the cropping tool and the area you wish to crop.  Once that is done, use the Copy button in the Tool palette to record your crop setting.

DDP4 - Cropping with the Tool palette

DDP4 – Cropping with the Tool palette

You then need to open each file individually and Paste the crop setting using the Tool palette. Once you’ve done all of that, you can select all your images and run the Batch process to save them to 16-bit .TIF as explained above.  No need to resize if you’ve cropped.

DDP4 - Image selection pane shows the crop box around each image.

DDP4 – Image selection pane shows the crop box around each image.

Now on to alignment and stacking with Registax

Then it’s simply a matter of opening the resulting .TIF images in Registax as you would normally.

moon-raw-3

Once the alignment completed and the images stacked, your photo can be saved

moon-raw-4

But before you close the program, head over to the Wavelet panel and tweak the image to get as much detail out of the moon’s cratered surface.

moon-raw-5

If you compare both images it is clear that the 2nd one has sharper details.

As always, the best is to try different things and experiment with your setup to see what works best.

Equipment used for the above photos:
Canon 80D
Skywatch 80ED (600mm F7.5)
1/250sec ISO 200

Wide Angle Photography – Perseus

Image

Shooting wide angle long exposures of the sky is always fun, because you never quite know what you will get. On an August night I decided to take a few 20 seconds exposures of the constellation Perseus hoping to catch a few open clusters.  However got surprised by the faint glow of Messier 33 (Triangulum Galaxy) in the photos. This is the furthest object that can be observed to the naked eye, located 2.7 million light years away, and part of the Local Group which includes Andromeda and our Milky Way.

Constellations Perseus and Triangulum (Benoit Guertin)

Constellations Perseus and Triangulum (Benoit Guertin) – CLICK FOR FULL SCREEN

4 x 20 seconds
ISO 6400
17mm F4.0
Canon 80D
August 30, 2019

For the Moon, leave the tripod behind

Most people don’t plan to take photos of the Moon, they just happen. You are outside doing something else and then you spot it over the horizon or high in the sky: “Hey that’s a pretty Moon tonight Maybe I should take a photo!”

I find that normal camera lens, even telephoto don’t do it justice. The setting and focus can be very tricky. The multi-lens setup of telephoto can also cause internal reflections or chromatic aberrations making the resulting photo less appealing.

So just grab the telescope tube and leave the tripod behind.  If you have a small APO refractor you can simply hold the tube, but for anything heavier you’ll need to prop yourself up on something like a railing or a car roof.

The photo below is a single shot at 1/250sec and ISO400 with Canon 80D and William Optics Gran Turismo 71 held on the end of my arms.

2018-08-31

80% Illuminated Moon on August 31, 2018 [Benoit Guertin]

The setup takes only a few minutes and the results are always worth it.

Mars and the Milky Way

Campgrounds are offer good occasions to observe the night sky; away from the city lights or industrial parks.  And with little more than a camera on a tripod, some fantastic pictures can be taken.

But there are two drawbacks:
1) Campers make campfires that create a haze near the ground.
2) Trailers and vehicles often have lights on that ruin the show.

Mars (left) and the Milky Way - Benoit Guertin

Mars (left) and the Milky Way – Benoit Guertin

Messier 3 and a Fast Moving Star

A few weeks ago after taking some photos of Jupiter, I changed my setup to do some long exposures on an easy target: a globular cluster. Unfortunately I forgot to note down the name of what I had photographed!  So a few weeks later when I found the time to process the images I was at a loss to identify what Messier object it was. However, after an evening of matching up stars surrounding the cluster and I was able to correctly identify it as Messier 3.

Globular Cluster - Messier 3 (Benoit Guertin)

Globular Cluster – Messier 3 (Benoit Guertin)

The above was taken with my Skywatcher 80ED and Canon 80D. It is a stack of 27 x 10sec exposures at ISO3200 on an unguided and roughly aligned mount.

Looking at my archives I found that I had imaged M3 about 10 years ago with the same telescope, so I decided to align both old and new image and see if anything would stand out. And to my surprise, spotted one star that appeared to have shifted. To help identify the star I colorized one of the photos and subtracted from the other (done in GIMP).  All the stars within the field of view lined up except this one; the two colored spots are not aligned!

High PM Star BD+29 34256

High PM Star BD+29 34256

To be sure this wasn’t on an error on my part I did a bit of research and found it to be a know high proper-motion star BD+29 34256.

It’s not everyday someone with amateur backyard astronomy gear can show how a star has moved in 10 years.