Rho Ophiuchi with Rokinon 135mm

The main reason for purchasing the Rokinon 135mm was a quest to shoot Rho Ophiuchi, an object I wanted to shoot for a long time. It stands out for its multiple bright colours, vivid dust lanes and even has a star cluster. After learning about it some time ago, I realized it was too big to fit into the field of view of my ED80. But at 135mm, it fit perfectly into D5300’s crop sensor. When the lens arrived, I quickly realized that due to its weight, there was no chance of attaching it to the guide scope without some support. A clear night was quickly approaching, and I didn’t have the time to order proper mounting rings for it. So I put together a support for the lens made out of balsa wood and wound heavy-duty twist tie to keep it snugly in place. Finally, I set out to a Bortle 3 location to try my luck.

Quick and dirty attachment of Rokinon lens to mount

From Ontario, Rho Ophiuchi is very low in the sky and the window to shoot is short. I started imaging at midnight and by 1am, the star complex was getting too low and approaching light pollution at the horizon. I ended up taking 23 images. Fast forward a year later and I finally got around to processing this.

You begin any processing with a set of images from your session. Each image contains a bit of signal (the good part) and a bit of noise and light pollution.

A single 3 minute sub from a Bortle 3 site

Now its time to stack your frames to increase the SNR (signal to noise ratio). Because there is light pollution in the subs (individual images), you inherently also stack or add up the light pollution also. In result, your improved signal is hidden behind a thicker layer of light pollution that turns the photo to this:

23 3-minute subs are stacked to produce this image

Your next task is to remove the light pollution. As light pollution is never evenly spread across the sky, it becomes a challenge to remove this unwanted gradient. Luckily Pixinsight has a great tool for this called DBE (DynamicBackgroundExtraction). After some tinkering with its settings, I subtract the pollution gradient from the image, and you finally begin to see the object, with its signal amplified by the stacking process.

Light pollution gradient removed using DBE in Pixinsight

At this stage, there is still a lot of work left, but seeing your deep space object gives you a drive to move forward. After some color balance and stretching the image to a non-linear state, you arrive closer to the finished product.

Color calibrated and stretched image

The final steps are to do some noise reduction on the grainy parts, increase sharpening, contrast, and saturation to bring out the color. All these steps require careful masks in order to not apply these affects to the whole image, but only the parts you want improved. Finally, a small star reduction to bring out the object more to the foreground, and we finally have a complete astrophotography image.

Final image of Rho Ophiuchi
GEAR USED

Rokinon 135mm f2
D5300 Ha modded
AVX mount
ST80/QHY5L-II quiding
Sharpcap alignment

IMAGE ACQUISITION DETAILS

23 subs × 180s (dithered)
50 flats and 50 bias

TAKEN AT
Torrance Barrens Dark-Sky Preserve Map
Imaging session @ Torrance Barrens Dark-Sky Preserve

IMAGE PROCESSING

Stacked in DSS, processing in Pixinsight

Dynamic crop
DBE
Background Neutralization
Color Calibration
Histogram Transformation
Local Histogram Equalization
Multiscale Linear Transform
Curves
SCNR Green
Dark structure enhance
Morphological transformation for star reduction

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IC1396 – The Elephant Trunk Nebula

A bicolor narrowband DSLR image. With a Baader 2″ Ha 7nm and a Baader 2″ Oiii 8.5nm filters from Bortle 7-8 area of my home. 6 nights in total for 25 hours of exposure!

IC1396
IC1396 using ED80 and D5300Ha – 25 hours exposure
GEAR USED

D5300 Ha modded
AVX mount
Orion ED80 with 0.85 reducer
ST80/QHY224C quiding
Sharpcap alignment

IMAGE ACQUISITION DETAILS

52 subs × 900s for Ha (dithered)
49 subs x 900s for Oiii (dithered)
25 flats for each
50 bias for each
12 darks for single Oiii session

TAKEN AT
King City Map
Imaging session @ King City

IMAGE PROCESSING

DSS and Pixinsight 

Stacked in DSS, processing in Pixinsight

Same steps for Ha and Oiii channels:
– Debayered strong channel extracted
– DBE
– Deconvolution
– MLT
– Histogram transformation

Star alignment of Oiii with Ha image

LRGB Combine:
L: Ha
Red: Ha
Green: Oiii
Blue: Oiii

SCNR
Curves
Unsharpmask
Star Reduction

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Milky Way Core Mosaic Widefield with Rokinon 135mm

A mosaic of the center of our home galaxy using 14 panels with a Rokinon 135mm f2 lens and Nikon D5300 h-alpha modified.

Unfortunately, not a perfectly clear night, and so some panels had slight cloud cover, hence a difficult job in stitching together. But a very good practice for my first mosaic.

14 panels
2 subs x 1 min at f2 iso400
Rokinon 135mm F2 lens
Nikon D5300
Advanced VX mount
ST80/QHY5L-II Guiding

Calibrated in dss
Stitched in msici
Pixinsight: dbe, star masks, star reduction, lots of curves and histogram, remove green and thats it

Milky way 14 panel mosaic with Rokinon 135mm f2

Original image is 196 megapixels, and is 20,000 pixels wide. For a 7,000 wide version: https://www.flickr.com/photos/152646221@N02/42065677755

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3D printing Bahtinov masks and lens mount rings

Recently I found out that a number of Toronto libraries have 3D printers available to the public. Printing there is extremely cheap. A fee of $0.10 per one gram of filament (printing material) is charged for each print job. Your only task is to find a model to print. Luckily, thingsverse.com is a website that has a huge catalog of 3D models available for download.

First and foremost, I needed a way to mount my Rokinon 135mm lens in a stable way. The lens weighs in at 816g and is imposible to attach to the mount without some rings supporting it.

Searching thingsverse.com, I found a model designed specifically for the Rokinon 135mm f2. I also noticed a dedicated Bahtinov mask suited specifically for the hood size of the lens. After downloading both, I went to the library to make my first 3d prints.

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C49 – Rosette Nebula

I set out on a trip to a Bortle 2 sky to Nirvana, north of Bon Echo Provincial park. As usually, I packed everything in my MDX, and set out early evening around 4pm. The trip is close to a 3 hour drive, in addition I also need a time buffer to setup which takes typically 90 minutes.

All gear packed and ready to go

Driving to past Bon Echo provincial park, the road turn very scenic, and my excitment is high. We are approaching one of the best astro sites in Southern Ontario. It lies evenly distant from light polluted urban metros of Toronto and Ottawa. Due to this, it is one of the most darkest, southern places you can visit.

Coming up to Mazinaw Lakes, in Bon Echo Provincial Park

My biggest scare was 3 minutes from the site. After leaving the highway and turning deep into a forest track leading to my destination, I noticed that the trail was heavily covered in snow. We are deep in wild territory, and obviously there is no snow cleaning here. Everything was fine until I got to the final stretch of the path. To get to the abandoned airfield, you must get up a steep hill. In the summer this is effortless, but on a snow covered road, deep in a forest with ravines on either side of the road, this turned out to be very hard. No matter how hard I tried to get up, I ended up spinning my tires, and forced to back up down the hill. It was getting dark and hard to see, and I began to panick. I had to get my car up there, since I needed to use my car’s battery to power the rig as a backup power source. Luckily, after 25 tries, I managed to get up the hill by turning off traction control. When I arrived at the top, I was rewarded with the following view:

Nirvana aka Irvine Lake landing strip – Bortle 2 location

All that was left was to setup. Even though it was cold, my excitment was keeping me warm. Ahead was a photo that I’ve been dreaming about a long time.

Getting ready to setup

The Rosettte Nebula is a nebula that looks like a beautifull flower. It has strong Oiii signal in the center which makes it look colorful and dynamic.

In the end though, I struggled with my guiding. A combination of the objects location and average seeing conditions probably affected my ability to guide below my recommended RMS of 1.58″. My PHD graph was showing horrible RMS values – around 1.2 for DEC and 1.6 for RA. This prevented me from having pin point stars that in turn produce a sharp looking image.

C49 – The Rosette Nebula

Orion ED80 with x0.85 reducer and GSO focuser
Advanced VX mount
Nikon D5300 h-alpha modded
ST80 with QHY5L-II for phd guiding
Sharpcap polar alignment

12 dithered subs @ 200 iso x 480s = 1h 36min total
30 bias
30 flats

Imaged using BackyardNikon, Stacked in DSS, processing in Pixinsight.

Dynamic crop (just edges)
DBE
Background Neutralization
Color Calibration SCNR Green
Luminence mask
MLT noise reduction on background
Histrogram transformation
Mask with stars mask subtracted for:LocalHistogramEq
Histogram adjustment
MLT Chrominance
Color saturation adjustment
Curves adjustment
Morphological transformation for star reduction
Dark structure enhance

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M13 – The Hercules Cluster

Not very happy with the guiding during this session. The weight of the C6N along with the overweight guidescope (ST80) presented a lot of issues getting good RMS. In addition, my reflector’s focus and/or collimation was a hair off. But it is what it is 🙂

GEAR USED

Celestron 6″ Newtonian
AVX Mount
H-alpha modified D5300
ST80/QHY5L-II-M

IMAGE ACQUISITION DETAILS

10 subs x 180s seconds (dithered)
PHD guiding, BackyardNikon
DSS, Pixinsight

TAKEN AT
Long Sault Conservation Area Map
Imaging session @ Long Sault Conservation Area

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Saturn in all its glory

After imaging Jupiter, my next planet in the list is obviously Saturn. The only planet in the solar system with a prominent ring system, this one needs no introduction. My first tries imaging this with the low quality 80mm chromatic telescope produced a very tiny and yellow dusty colored oval patch. I did not have enough focal length to really get to the details. But now I have the Televue 3x Barlow for the magnification, and with proper color balancing in SharpCap, I should get much better results. After waiting for a clear night with descent seeing, I tried my luck. Here is the my image of Saturn:

Saturn using Celestron 6″ Newtonian and QHY224c

I shot 10,000 frames using SharpCap, stacked using Autostakkert 2500 best frames, used Registax for wavelet processing and Photoshop for saturation and canvas increase.

Video from Beygin Astrophotography

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Finally captured Jupiter’s Great Red Spot

By using Mobile Observatory app for Android, I found the optimal day to shoot Jupiter. The planet not only had to reveal the red spot, but it had to do so while being as high up in the sky as possible. Living in Toronto results in planets being lower in the sky. Planets that are closer to the horizon are behind more atmosphere, resulting in more turbulent, blurry images. Finally, I waited for good seeing and transparency conditions as indicated on the cleardarksky.com website.

Hover over image to see moon labels

Celeston C6N & AVX

QHYIII-224C

Televue 3x shot at around f20

The secret in getting detailed images of planets is a planetary camera. The problem with a DSLR as you probably know is getting a high frame rate. Also, the pixel size is usually slightly larger.

If you get a USB 3.0 camera, you can get very fast frame rates. Since you never shoot at full resolution (a planet usually never occupies more than 320×240 pixels), you get to increase the frame rate. Frame rate is directly related to your exposure setting. So if you keep your exposure at 5-10ms, you get between 100-200 frames per second. The trick is to lower the exposure as low as possible, and then increase the gain to reach a 75% histogram. Shooting using these planetary cameras is extremely easy, they are compatible with some very great software. Also, they double up as guide cams.

I shot this image at 140fps. But the camera can shoot much faster. I took about 6000 frames in 42 seconds. That way, I get very little rotation in the image. Finally, I only pick about 15% of the images, the best of the very best. And then I stack those. That way I get the clearest possible image, and at 15%, I’m still stacking 900 frames.

QHY224C is an amazing camera. The most popular one is ZWO’s ASI224, but not a lot of people know that the QHY224C has the same SONY sensor. The difference is that you also get a passive cooling design, and anti-amp glow, which is important for longer exposure shots.

For focus, there are many methods to focus. You can use a Bahtinov mask. I personally just focus on a star. Right now, Spica is close by, and so I slew to Spica, and using FWHM, I get the star as small as possible. It is very tricky, because the C6N focuser is really coarse, but at least it holds the focus well (since the focuser is stiff).

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Jupiter in colour using QHY224c

This is my first color image of Jupiter using my new QHY5-III-224c camera. Taken with a Celestron C6N, AVX Mount, and a Televue 3x barlow.

The seeing was average. I took 4000 frames at 10ms/17gain and picked the best 15 percent to stack in Registax. Finally I performed wavelet sharpening and final touches in Photoshop.

Jupiter with Europa moon transit

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