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ZWO ASI2600MM Pro

Photographing the Sunflower Galaxy

|Galaxies|4 Comments

In this post, I will share the techniques and equipment I used to take a picture of the stunning Sunflower Galaxy. With the world largely shut down for me, deep-space astrophotography in the backyard has been a welcome escape. 

Cataloged as Messier 63, this stunning galaxy is about 25 million light-years away from Earth in the constellation Canes Venatici. The months of April and May are the perfect time to photograph M63 from mid-northern latitudes.

You can also watch the video of this process on my YouTube channel:

Photographing the Sunflower Galaxy

The spring season is nicknamed “Galaxy Season” for astrophotographers in the northern hemisphere because there are so many interesting deep-space galaxies up for grabs at this time of year. 

If you’re typically a “nebula guy” like me, photographing galaxies is a nice change of pace, and the approach to the image is quite different than a large nebula.

Galaxies are typically much smaller in apparent size than nebulae, and emit light in the broad spectrum.

Image Scale

The size difference between a large nebula and the Sunflower Galaxy (to scale).

You can’t use narrowband filters to ignore the light pollution from the city the way you can with nebulae, and achieving a natural look to the galaxy and surrounding stars may take some time to get right.

Some people prefer to use a mild light pollution filter when imaging broadband targets with a color camera. I recommend the Optolong L-Pro filter for those looking to capture long exposure images with more contrast from the city. 

After 3 years of use, this filter continues to provide the best results for one-shot-color, broadband astrophotography from my location. Shooting unfiltered is my only other option, and this method can be hit-or-miss depending on the target.

To photograph the Sunflower Galaxy, I used a sensitive monochrome CMOS astronomy camera with LRGB filters. This camera uses a motorized filter wheel that allows me to select the filter I want to use without touching the camera.

Telescope filter wheel

I use a ZWO 7-position (36mm) filter wheel with my dedicated astronomy camera.

Planning the Shoot

All of the photos I capture from the backyard are shot through heavy light pollution (Bortle Scale Class 7), and the seeing conditions are often poor as well. There is no substitute for dark skies, but backyard astrophotography in the city can be done, and the results may surprise you. 

The moon (80% illuminated) was out during this session, which is not ideal for capturing true-color images of galaxies, but I’ll take what I can get. Generally, you’ll want to avoid capturing galaxies when the moon is full, as this light diminishes the contrast in your image and washes out faint details. 

On the night of this imaging session, the forecast was cold and clear, and that’s enough for me to set up my telescope. Spring is a great time for astrophotography because the nights are still long, but the temperatures are a lot more tolerable. 

backyard astrophotography

My humble backyard in the city (and Rudy). 

I am getting better at planning my astrophotography sessions. The ‘old me’ would just see a clear forecast, start setting up, and ‘figure it out’ from there.

But without planning, you will always lose precious clear sky time googling examples of targets to image and potentially selecting something that isn’t a good fit for your skies or your gear.

I use Stellarium for isolating object types, size, and location. I even have a custom landscape (my backyard) loaded in so I can see when certain objects will clear the house or run into the tree.

Stellarium is great for filtering deep-space objects by apparent size, and magnitude, so you can isolate targets that are a perfect fit for your imaging setup. 

Stellarium software

I imported a custom landscape into Stellarium to see where objects will appear in the night sky from my backyard.

Astrospheric is one of the more reliable weather apps out there, and it’s usually the one I can safely plan my imaging sessions around. I actually use a mixture of weather forecasting apps, but I enjoy the level of detail and layering of Astrospheric best. 

I also like to hop on AstroBin to see examples of the exact object I’m about to shoot and filter the images down to ones using the same telescope I have. Not only will you get a better idea of the size and image scale of your target, but a detailed breakdown of the exposure lengths and filters used.

It is a truly remarkable resource. You can register for AstroBin using this link for 20% off a subscription. It is well worth it!

Filter it down even more to a “top pick” version, and get inspired by some of the most amazing amateur astrophotos you’ve ever seen.

Related Article: The 19 Best Astronomy and Stargazing Apps for You Mobile Phone

My Telescope

I’ve been getting a lot of use out of my Celestron Edge HD 11 Schmidt-Cassegrain telescope this galaxy season, and it’s currently the scope with the highest native magnification I own right now.

Normally I love a nice fast apochromatic refractor, but the object is only 10 x 6 arc-minutes in size. I appreciate nearly 2000mm of focal length with this telescope (when the reducer lens is used). 

Celestron Edge HD 11

My Celestron Edge HD 11 telescope.

It’s been nice to use the Edge HD 11 this galaxy season, last year a lot of people were excited about this telescope and I am glad to come through on my promise to get some impressive images with it.

Flat frames have been a little challenging with the scope. There is no getting around not taking flats for a broadband image in this much light pollution.

I’ve had to do lots of tests to get it right, including experimenting with different exposure lengths and using different materials to filter the objective. I do not own a dew shield yet for this telescope yet, which is not ideal

Trevor Jones

I use a 0.7X reducer lens on my SCT for faster more light-gathering power and a practical focal length.

I am using a ZWO ASI2600MM Pro camera to capture the Sunflower Galaxy, which requires a set of LRGB filters to create a full-color image. 

This camera has been an absolute dream thus far, and I know it will be a popular choice for amateur astrophotographers moving forward. 

My Approach

I am trying a new approach to galaxies and LRGB imaging in general. I’ve decided to capture much shorter exposures through each RGB filter than I typically would.

In contrast, I’ll take longer exposures through the luminance filter, in an attempt to collect the important details of the Sunflower galaxy structure. 

I notice that a lot of great astrophotographers will capture galaxies using shorter exposures in RGB, and longer for the luminance (LUM), and that’s exactly the approach I used to photograph the Sunflower Galaxy.

ZWO ASI2600MM Pro camera

The camera is a ZWO ASI2600MM Pro monochrome CMOS camera.

I collected an hour through each color filter and 1.5 hours in luminance data. The RGB exposures were 90-seconds each, and the luminance were 3-minutes each.

The idea was to capture enough quality color data to provide the overall natural color of the object and use the grayscale luminance data for the details.

I run the ZWO ASI2600MM Pro camera at Unity Gain, and Bin the Images 1 x 1. I have been advised to capture my images Binned 2 x 2 with this setup, and drizzle the data (during the integration/calibration stage) to retain the native image resolution.

The idea to capture more data in a shorter amount of time by increasing the pixel size (using software binning). It sounds too good to be true, but I’ll test this method out over the coming weeks and report back. 

my telescope

My telescope pointed towards the Sunflower Galaxy. 

This telescope shoots at F/7, so I’m not sold on going as short as 30-60-seconds. If your telescope is in the F/4 range, a 30-second exposure is likely all you’ll need for RGB.

Image Acquisition and Autoguiding

My little autoguiding system with the ZWO ASI290mm Mini and 72mm refractor has been working fantastic on this rig. Guiding with PHD2 has been extremely accurate, and I simply don’t have to worry about it whatsoever.

The ASI290MM mini is one of the best-selling guide cameras on the market, and it happens to be an incredible planetary camera as well (I used it to photograph Mars and Saturn last summer).

The guide scope has a focal length of 420mm, which I am happy to say has been more than adequate to effectively guide this big SCT.

autoguiding setup

I use a 72 doublet refractor (420mm) mounted to the upper rail of the SCT for autoguiding. 

I have it clipped onto the top rail of the Edge HD 11, and I really like that I can easily shift the system back and forth on top of the OTA to achieve balance.

With the telescope accurately polar aligned (using the QHY PoleMaster) and balanced, a quick star alignment routine was all that was needed for precise pointing accuracy. 

Results

Overall, I am happy with the image of the Sunflower Galaxy I was able to capture. The new (proper) approach to LRGB imaging seems to be paying off, and I will certainly employ this technique again in the future. 

The image is a little soft, in my opinion, but that is largely due to the heavy cropping from the original image frame, as well as my personal processing style for this target.

To create a stronger image, I believe collecting data under a dark, moonless sky is required. Unfortunately, a big galaxy rig like this is tough to travel with. 

sunflower galaxy

The Sunflower Galaxy. 4.5 Hour Exposure. 

Processing the image was time-consuming, but also a lot of fun. I stacked each set of LRGB image exposures separately in DeepSkyStacker, and built the image in Adobe Photoshop using channels. 

I outline this process in a video found in my premium image processing guide. 

Image Processing Guide

The Sunflower Galaxy is a deep-space object that can take your breath away when you see that first exposure appear on the screen.

Whichever galaxies you’ve been photographing this spring, I hope you take a moment to soak in the experience.

In terms of hobbies, astrophotography is like nothing else. I sincerely hope it brings you as much joy as it does to me. Until next time, clear skies!

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ZWO ASI2600MM First Impressions

|Camera|8 Comments

The ZWO ASI2600MM Pro mono is the much anticipated monochrome version of ZWO’s popular ZWO ASI2600MC Pro dedicated astronomy camera. It houses a 26 Megapixel Sony IMX571 back-illuminated sensor, and some seriously impressive specs.

This camera uses a highly sensitive, cooled, monochrome CMOS sensor in the APS-C format. The size and resolution of this sensor is its biggest selling feature.

The ZWO ASI2600MM Pro not only improves on nearly every aspect of its predecessor (the ASI1600MM), the sensor is now APS-C, capturing a larger field of view. In the land of deep space astronomy cameras, the APS-C sensor size is said to be “the sweet spot”, balancing a large field of view with a practical size for demanding optical systems.

If you are thinking about purchasing your first monochrome camera for astrophotography, this would be an excellent choice. It is well supported, features some of the best camera specs in the industry, and is a practical system for a wide variety of telescope configurations. 

Order the ZWO ASI2600MM Pro

Due to its impressive specs and versatility, I believe the ZWO ASI2600MM Pro mono will be one of the most popular cameras for astrophotography in 2021, and beyond. ZWO sent me an early version of the ZWO ASI2600MM Pro to test in my backyard, and report my results. I was not compensated in any way to review this camera, nor was I given any directions of what to talk about. 

ZWO ASI2600MM Pro example image

First light using the 2600MM Pro. 20 x 5-minutes in H-Alpha (3nm Chroma filter). 

The ZWO ASI2600MM Pro Mono

The ZWO ASI2600MM Pro is a lightweight, cooled CMOS astrophotography camera that specializes in deep-sky imaging. This camera shares some features with its ASI1600MM counterpart but there are many upgrades to the 2600MM Pro including; a higher image resolution, a back-illuminated sensor, built-in dew heater, higher full well depth, and quantum efficiency.

In fact, the well depth of the 2600MM Pro is more than twice that of the ASI1600 (50K vs. 20K), and the quantum efficiency is rated to be an impressive 91%. This is the highest QE CMOS camera I have ever used for deep-sky astrophotography. 

Trevor Jones

The 2600MM Pro remains lightweight, although it is slightly heavier than the 1600MM Pro at 1.5 lbs (0.7 kg). The look and feel of the 2600MM Pro are similar to other ZWO cameras with the same port for power, cooling, and USB 3.0 hub.

OPT Telescopes shared this video about this camera in early February, and it does a great job of explaining the key specifications of the camera.

As with other monochrome cameras, filters are needed with the ASI2600 to produce a full-color image. Many will use this camera for narrowband imaging, but this astronomy camera would make an excellent LRGB imaging workhorse as well.

A power cable is needed for powering the cooling system that will control the sensor temperature and help to reduce noise in your image. If you are looking for a suitable power supply for the ZWO ASI2600MM Pro, I recommend using a 12V 5A AC/DC adapter as described on the ZWO website

ZWO ASI2600MM Pro

ASI2600MM Pro Mono Key Features and Specs

Sensor:

The 2600MM Pro camera features a 26-megapixel sensor that provides a wider/larger field of view with increased dynamic range to deliver clear, crisp images. Another feature of the 2600MM Pro sensor is the back-illuminated sensor. This helps to reduce noise and eliminate amp glows produced by weak infrared light that appear in the corner of uncalibrated images.

Pixel size:

Pixel size of the 2600MM Pro is 3.76um. The combination of 3.76 um pixels and a larger sensor allow for a much larger resolution and overall image with a full resolution of 6248 x 4176.

You can calculate the pixel scale of your camera system by combining this value (3.76), and your telescope’s focal length. The ideal range is about 2.0 for a well-sampled image, but this is only a general rule of thumb based on optical seeing conditions. 

The calculation is pixel size divided by focal length, x 206. For example, when pairing this camera with my Sky-Watcher Esprit 100 telescope, I reach a pixel scale of 1.4. (3.76 ÷ 550 x 206 = 1.4)

ASI2600MM Mono

The ASI2600MM Pro mono is noticeably larger and heavier than my ASI294MC Pro and ASI533MC Pro. 

Full Well Depth:

Full Well depth (along with bit depth), give you a better dynamic range, allowing you to take longer exposures before data clipping occurs and avoid unwanted light and bloated stars. The 2600MM Pro has a full well depth of 50,000 e which is more than double that of the ASI 1600MM Pro.

The full well capacity of a camera (sometimes called pixel well depth or just well depth) is a measurement of the amount of light a photosite can record before becoming saturated, that is no longer being able to collect any more.

Quantum efficiency:

Quantum Efficiency (QE) and read noise are the most important aspects of a dedicated astronomy camera. QE can be summarized as the percentage of light that hits the sensor and gets recorded into the final image.

A high QE and low read noise are critical for improving the signal-to-noise ratio (SNR) of an astrophotography image.  

The ZWO ASI2600MM Pro boasts an impressive QE peak value of 91%, which is even higher than the QE peak for this camera’s color counterpart (6200MC Pro). 

The 2600MM Pro records and converts 91% of the light hitting the sensor into a usable image which is 31% more light than the 1600MM Pro.

Read Noise:

Read noise is the noise created by the camera and includes pixel diode noise, circuit noise, and ADC quantization error noise. Essentially, the lower the read noise of your camera, the better.

The Read Noise of the ASI2600 is extremely low when compared to a traditional CCD camera. The ASI2600MM also includes a built-in “HCG mode”, which helps to reduce read noise at high gain while retaining the wide dynamic range for this camera as at low gain.

The best gain setting for the ASI2600MM Pro will depend on your astrophotography target. You’ll want to set the gain lower for a higher dynamic range (longer exposure) or set the gain higher for lower read noise in a shorter exposure project or lucky imaging.

A strong signal in a long exposure image will overcome read noise, and the calibration process of subtracting dark frames and bias frames will help correct this even further. 

Anti-Dew Heater:

The 2600MM Pro also includes a built-in dew heater that fits in the protective window of the camera to combat dew or ice and keep condensation off your sensor.

The dew heater can also be turned off at any time should you not want to use this feature or to save power.

Protective Window:

The 2600MM Pro includes a protective window in front of the camera sensor. The window is 60mm in diameter and 2mm thick.

Keep in mind that this is an AR (anti-reflective) coated filter, while ASI2600MC Pro (color) uses an IR CUT filter.

Cooling System:

The 2600MM Pro is designed with a two-stage cooling system that can cool the camera sensor below 35°C reducing sensor noise and exposure time.

ZWO recommends that you use a 12V @ 3A DC adapter to power the cooling. The exact connection for power on the camera is 5.5mm x 2.1mm (center pole positive). A 12V 5A power adapter is a common choice, and what I personally use. 

Native Bit Depth:

The 2600MM Pro has 16-bit ADC and can achieve a dynamic range output of 14 stops to improve sharpness and contrast while allowing for smooth color transitions with gradients.

The ASI2600MM Pro supports 2×2,  3×3,  4×4 software binning (and Bin 2, Bin 3 hardware binning). 

Frames per second:

Since the 2600MM Pro has a larger sensor and bit depth it is not able to record data as quickly at only 3.5 frames per second. This is one noticeable advantage of the 1600MM Pro, which may be better suited for recording planetary data or video that you plan on stacking.

This camera supports custom ROI readout modes, which allow for faster frame rates at a smaller resolution. The ZWO ASI2600MM Pro can shoot a whopping 51 FPS when shooting at a tiny 320 x 240 resolution. 

cooling fan

The cooling fan and connector ports at the back of the camera. 

The 256MB DDR3 memory buffer inside of the camera helps manage a stable transmission of data from the camera to your computer. 

ZWO ASI2600MM Pro vs. ZWO ASI1600MM Pro

The ASI2600MM Pro is a monumental upgrade from the aging ASI1600MM Pro in every key category. Notable improvements are in quantum efficiency, well-depth, and overall resolution. 

Please see the comparison chart below for a complete overview:

Specifications ASI2600MM Pro ASI1600MM Pro
Weight 1.5 lbs 1lb
Sensor Monochrome Monochrome
Sensor model Sony IMX571 CMOS MN34230
Cooling System Built-in Built-in
Resolution 26 MP APS-C 16 MP Micro Four-thirds
Pixel Size in microns 3.76 3.8
Back-illuminated sensor Yes No
Built-in Dew Heater Yes No
Full well depth 50,000 e 20,000 e
Quantum Efficiency 91% 60%
Frames per second 3.5 23
Price $2,480 $1,280

ZWO ASI2600MM Pro Specifications

  • Sensor Type: CMOS
  • Sensor: Sony IMX571
  • Mega Pixels: 26.1 MP
  • Pixel Array: 6248 x 4176
  • Pixel Size: 3.76 microns
  • ADC: 16 bit
  • Back Focus: 17.5 mm
  • Camera Connection: M42 X 0.75
  • Color or Mono: Monochrome
  • Cooled: Cooled
  • Full Resolution Frame Rate: 3.51fps
  • Full Well Capacity: 50ke
  • Max Frame Rate: 16fps
  • Peak Quantum Efficiency: 91%
  • Read Noise: 3.3e
  • Sensor Diagonal: 28.3 mm
  • Weight: 1.5 lb

Configurations and Back Focus

As with any dedicated astronomy camera, reaching the ideal back focus is critical to maximizing your results. Thankfully, ZWO provides a detailed back focus guide to achieve the recommended 55mm back focus of the ZWO ASI2600MM Pro. 

I will be using this camera with a ZWO 8-position filter wheel with 36mm filters. This adds 20mm of spacing to the camera configuration, and I will need to keep that in mind when building the imaging train.

camera attached to telescope

The camera attached to my Sky-Watcher Esprit 100 refractor telescope.

For now, I have the ZWO ASI2600MM Pro attached to my telescope using a 2″ filter slider drawer and a 16.5mm adapter. This allows me to insert 2″ round mounted filters into the imaging train until my new set of narrowband filters arrives. 

ZWO ASI2600MM Pro backspacing

My current backspacing configuration of the ZWO ASI2600MM Pro.

I have the camera attached to my Sky-Watcher Esprit 100 APO to enjoy a wider field of view than I am used to with this telescope. The camera system threads directly to the dedicated field corrector (M48 threads) of the telescope. 

A notable change in backspacing between the ASI1600MM and the 2600MM is the depth of the sensor from the front of the camera body (17.5mm). Those upgrading from the ASI1600 will need to keep this in mind when building out the new system. 

This camera also includes a tilt adjustment feature, which can be adjusted by using the 3 sets of screws found on the black flange of the camera. I would not recommend changing the factory tilt of the camera flange unless you are sure that there is a tilt issue in your optical train. 

Drivers and Camera Capture

I will be controlling my ASI2600MM Pro using Astro Photography Tool via the ZWO drivers. The ZWO website includes an extensive list of camera drivers for all of their dedicated astronomy cameras.

The latest ASI Cameras driver must be installed on your computer first, and then the ZWO ASCOM driver that supports all ZWO cameras, the EAF (electronic automatic focuser), and EFW (electronic filter wheel).

You can also read the full ZWO ASI2600MM Pro manual online which includes detailed performance graphs of the camera including the QE curve, dynamic range, and read noise. 

Included Items with the Camera

  • ZWO branded camera bag
  • ASI2600MM Pro Camera body
  • M48-M42 adapter
  • Printed Quick guide
  • USB3.0 Cable (2m)
  • M42-M42 21mm extender
  • M42-M48 16.5mm extender
  • 2″ cover
  • Hexagon wrench
  • 2x USB 2.0 cable (0.5m)

Final Thoughts

The reason the ZWO ASI2600MM Pro is such a practical choice for deep space astrophotography is the sensor size. If you have owned dedicated astronomy cameras in the past, chances are the sensor was smaller than APS-C.

For comparison, the ZWO ASI1600MM Pro has a micro 4/3 sensor, which is useful in most situations. However, you may find that a sensor of this size crops the field too much, and sacrifices the native focal length of your telescope.

I don’t know about you, but I would always take a little extra real estate on the camera sensor to collect larger deep sky objects in a single frame. 

Creating mosaics will be less common with this camera because you can gather so much sky in a single frame. Pair this camera with a short focal length refractor like the William Optics RedCat or Radian Raptor 61, and you’ll be photographing entire regions of nebulosity in the sky. 

The resolution of this sensor is incredible. I have enjoyed the small 3.76 micron pixel size of the QHY268C, and I am thrilled to now be able to shoot in monochrome with the ASI2600MM Pro.

Speaking of QHY, they too have a monochrome version of this sensor in the QHY 268M. This provides an alternative to the ZWO version for QHY fans looking for an affordable monochrome CMOS camera that delivers big results. 

The ZWO ASI1600MM Pro was one of the best-selling astronomy cameras ever, and for good reason. Some of the best amateur astrophotography images I’ve ever seen were captured using that camera. 

I believe the 2600MM Pro is poised to replace this camera’s prestigious position, and become a pivotal product in the astrophotography community. 

The ZWO ASI2600MM Pro is roughly twice the price of the ZWO ASI1600MM. I think it is priced correctly for the long list of improvements over the aging ASI1600MM Pro.

Seagull Nebula SHO

The Seagull Nebula in SHO. Captured using the ASI2600MM mono and Chroma 3nm filters.

Order the ZWO ASI2600MM Pro

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