Tag Archives: RGB

ZWO ASI6200 62mpx Full Frame Camera Review

I recently wrote a review on the ZWO ASI2400 24mpx full frame camera, so I thought I would also do the same for the big brother which is the ZWO ASI6200 full frame camera with a mammoth 62mpx which I picked up from 365astronomy when returning the ASI2400 after the review. Looking at both of the cameras, there is no obvious difference from the outside except for the model number, both cameras are exactly the same size and feel roughly the same weight and the build quality is identicallyu exceptional.

ASI6200MC Pro One Shot Colour Camera

If we compare the specifications of the ASI6200 to the ASI2400 we can see where each camera has an advantage over the other:

ASI2400ASI6200
Weight700g700g
SensorIMX410IMX455
Sensor SizeFull FrameFull Frame
Pixel Size5.94um3.76um
Resolution24mpx62mpx
Full Well Capacity at 0 Gain100ke51ke
Qe>80%91%
ADC14-Bit16-Bit
High Gain Mode140100
Full well at High Gain Mode20ke18ke

So as you can see from the comparison on specification there are some differences, the ASI2400 has the edge on full well capacity, however the ASI6200 has a much more smaller pixel size as well as a higher Qe which to me gives the ASI6200 the edge over the ASI2400.

Now since both cameras are the exact same field of view due to them both being full frame sensors, the question is how does this affect resolution, clearly the ASI6200 has the upper hand having significantly more pixels than the ASI2400, but how does this translate to an image?

Iris Nebula taken with the ASI2400MC Pro, 82x150S at Gain 26, darks, flats and BIAS frames applied
Iris Nebula taken with the ASI6200MC Pro 48x150S at Gain 100, Darks, Flats and BIAS frames applied

As you can see, both cameras offer the exact same field of view, however when you zoom in on the images you start to see where the ASI6200 excels above the ASI2400 with the higher resolution

On the left is the ASI2400MC Pro and on the right is the ASI6200MC Pro

As you can clearly see from the above two images, the 6200 offers a much better resolution which will allow a much finer level of detail, however, depending on your sky conditions and focal length the ASI6200 might not be possible due to over or under sampling

You can see here, that on my SharpStar 15028HNT which has a Focal Length of 420mm the ASI2400 would lead to Under Smapling in my “OK” seeing conditions

But the ASI6200 shows in the green area:

If I increase the focal length to around 1150 the ASI6200 no longer becomes suitable and the ASI2400 is more suited to this focal length and sky conditions:

So as you can see, both the ASI2400 and ASI6200 is not a “One Size Fits All” scenario, you have to work out the best suitability depending on your conditions and equipment to be used.

From a price perspective, the ASI6200 is only slightly more expensive than the ASI2400, but both cameras offer the full frame capability and a fantastic field of view, but for me personally the ASI6200 beats the ASI2400 when using the focal length of my SharpStar 15028HNT. Just like it’s smaller version, the looks, feels, sounds and operates exactly the same way. Here is another image taken with the ASI6200 and then my Synthetic SHO version which I will be writing a tutorial on how to acomplish with Dual Band Filters.

North America Nebula – 60x300S at Gain 100 using the Optolong L-eXtreme Filter on the SharpStar 15028HNT
Synthetic SHO using the same data as the previous image

Either way, both ZWO cameras I have tested have been of awesome quality, and I would recommend either camera if you wish to go down the full frame route, but personally my favourite is the ASI6200MC Pro, more images to come since this is now my new camera.

The source to the halo around bright stars

When I moved to the Sky-Watcher Quattro telescope I noticed some bizzare halo’s around bright stars in my images, this was evident in both my Atik 383L+ CCD Camera as well as my QHY183M ColdMOS Camera when using the Quattro 8-CF at F4, if you browse my galleries you will see what I mean, and it was more noticable in my Narrowband images. Below is one of my recent images where you can see the halo around Magnitude 3.9 star 15 Mon in the Christmas Tree Cluster / NGC2264.

I contacted Baader back in February 2019 since all of my filters were Baader, and I noticed that the Halo was present in all of my filters but significantly less in Red, but more prevalent in Narrowband filters, so the logical cause would be the filters. Baader immediately dismissed this to be the fault of their filters and suggested that my Coma Corrector be the root cause.

Not convinced that the Coma Corrector was causing the issue, I did some research online and came across a brilliant page on the Astronomik website where they claim to have resolved the majority of the Halo issue, and after reading the following line from the page I was convinced the filters were my issue:

In recent years very fast optical systems have become popular for imaging. The energy in a filter induced halo grows exponentially as the f-ratio decreases. Additional to this, the smaller the FWHM band pass of the filter, the stronger the halo.

The above line described my issue perfectly so I mentioned this to Baader who again dismissed the possibility of it being their filters and again put the blame firmly to my optical train. Again not happy, I contacted Astronomik and Eric emailed me back very promptly and offered to send me out one of their 6nm Ha filters to test. A few days ago the filter arrived and I was able to perform some testing against the Baader filter also for comparison on the same star.

Since the star in my image above was of magnitude 3.9, I wanted to find something similar, so I found star Alhaud VI and proceeded to obtain 15x300S Exposures for each filter, and here are the results:

Astronomik 6nm HA filter, 15x300S with Darks and Flats applied
Baader 7nm Ha filter, 15x300S with Darks and Flats applied

So as you can see the Baader filter shows a high amount of Halo around the bright star and the Astronomik filter does not, now if this was something to do with the rest of the optical train there would be evidence in the Astronomik filter also.

Now I agree there will be some reflection in the optical train, all that glass in the coma corrector, the glass on the camera etc, so I thought I would have a look at both images in a bit more detail, zoomed in on the stars there is what appears to be a slight halo in the same place on both images:

Astronomik 6nm Ha Filter
Baader 7nm Ha Filter

So both filters show the Inner Halo which in my opinion would not be visible in an image, but again clearly the Baader filter has some reflection issues happening as you can clearly see two additional Halos. The interesting thing about all three Halos is that the central one visible in both filters has no relationship to the distances between the other two in the Baader, however the two outer Halos on the baader are the same distance apart as the middle halo is from the star, so clearly this is some sort of reflection.

Conclusion:
Astronomik have done a fantastic job at eliminating Halo artifacts around bright stars, clearly the Baader filters are causing major Halo artifacts because if this was the optical train then it would be evident in the Astronimik filters also, I suspect that the Baader filters are not optimised for faster focal ratio imaging systems. I have provided this information to Baader and await a response from them.

Good job Astronomik Filters

NGC4565 – Needle Galaxy in RGB

The Needle Galaxy is located int he constellation of Coma Berencies and is an edge on spiral galaxy at a distance of 30-50 million light years from earth

Image Details:
101x150S in R
101x150S in G
101x150S in B

Total Capture time: 12.6 Hours

Acquisition Dates: Jan. 28, 2019, Feb. 3, 2019, Feb. 25, 2019, Feb. 26, 2019, Feb. 27, 2019, March 26, 2019, March 29, 2019, March 30, 2019, April 1, 2019

Equipment Details:
Imaging Camera: Qhyccd 183M Mono ColdMOS Camera at -20C
Imaging Scope: Sky-Watcher Quattro 8″ F4 Imaging Newtonian
Guide Camera: Qhyccd QHY5L-II
Guide Scope: Sky-Watcher Finder Scope
Mount: Sky-Watcher EQ8 Pro
Focuser: Primalucelab ROBO Focuser
FIlterwheel: Starlight Xpress Ltd 7x36mm EFW
Filters: Baader Planetarium RGB
Power and USB Control: Pegasus Astro USB Ultimate Hub Pro
Acquisition Software: Main-Sequence Software Inc. Sequence Generator Pro
Processing Software: PixInsight 1.8.6

M78 / NGC 2068 in RGB

This is the first time I have ever imaged this object, I will re-visit next year when I will image at F2.8 with a wider field of view using a keller reducer.

Since this object is in the southern area of sky, I am limited by trees and the house on the data I can capture in a single night

Image Details:
101x150S – Red
101x150S – Green
101x150S – Blue

101 Darks, Flats and Dark Flats

Image Acquisition Dates: Jan. 1, 2019, Jan. 2, 2019, Jan. 8, 2019, Jan. 9, 2019, Jan. 27, 2019, Jan. 28, 2019, Jan. 30, 2019, Feb. 10, 2019, Feb. 20, 2019, Feb. 23, 2019, Feb. 24, 2019, Feb. 25, 2019

Equipment Used:
Imaging Camera: Qhyccd 183M Mono ColdMOS Camera at -20C
Imaging Scope: Sky-Watcher Quattro 8″ F4 Imaging Newtonian
Guide Camera: Qhyccd QHY5L-II
Guide Scope: Sky-Watcher Finder Scope
Mount: Sky-Watcher EQ8 Pro
Focuser: Primalucelab ROBO Focuser
FIlterwheel: Starlight Xpress Ltd 7x36mm EFW
Filters: Baader Planetarium RGB and Ha
Power and USB Control: Pegasus Astro USB Ultimate Hub Pro
Acquisition Software: Main-Sequence Software Inc. Sequence Generator Pro
Processing Software: PixInsight 1.8.6

M51 – Whirlpool Galaxy in LRGB

Another Image that I have previously imaged with the Atik Camera, again demonstrating a different resolution obviously showing off a bit more detail, here’s the image previously:

Equipment Used:
Imaging Scope: Sky-Watcher Quattro 8″ F4 Imaging Newtonian
Imaging Camera: Qhyccd 183M 20mpx ColdMOS Camera at -20C
Guide Scope: Sky-Watcher Finder Scope
Guide Camera: Qhyccd QHY5L-II
Mount: Sky-Watcher EQ8-Pro GEM Goto Mount
Filterwheel: Starlight Xpress Ltd 7x36mm EFW
Filters: Baader Planetarium 36mm LRGB Filters

Software:
Image Acquisition: Main Sequence Software SGPro 3
Guiding: PHD2
Image Processing: PixInsight

Target Details:
Name: M51 / NGC5194 / Whirlpool Galaxy
Constellation:Canes Venatici
RA: 13h 29m 53.00s
Dec: 47° 11′ 51.10″
Distance from Earth: >23 Million Light Years

Image Details:
Luminance: 101×150 Second Exposures
Red: 85×150 Second Exposures
Green: 85×150 Second Exposures
Blue: 85×150 Second Exposures
Total Exposure Time: 14.83 Hours

Acquisition Dates: 6 Apr 2018, 19/20/21 Apr 2018, 5/6/7/8/9 May 2018

 

 

 

Leo Triplet in LRGB

This is not the first time I have imaged this trio of trespassers, I have imaged them before on the same scope but with my previous Atik 383L+ CCD Imager, so again similar to M81 and M82, you can clearly see the difference in resolution the new camera offers, here’s the previous image taken from my previous post here:

Equipment Used:
Imaging Scope: Sky-Watcher Quattro 8″ F4 Imaging Newtonian
Imaging Camera: Qhyccd 183M 20mpx ColdMOS Camera at -20C
Guide Scope: Sky-Watcher Finder Scope
Guide Camera: Qhyccd QHY5L-II
Mount: Sky-Watcher EQ8-Pro GEM Goto Mount
Filterwheel: Starlight Xpress Ltd 7x36mm EFW
Filters: Baader Planetarium 36mm LRGB Filters

Software:
Image Acquisition: Main Sequence Software SGPro 3
Guiding: PHD2
Image Processing: PixInsight

Image Details:
Luminance: 101×150 Second Exposures
Red: 101×150 Second Exposures
Green: 101×150 Second Exposures
Blue: 101×150 Second Exposures
Acquisition Dates: 18/19/20/21 Apr 2018,  4/5/6/7/8/9 May 2018

Total Exposure Time: 16.83 Hours

Target Details: Leo Triplet
Constellation: Leo
RA: 11h 19m 36.15s
Dec: 13° 17′ 2.90″
Distance from Earth: 35 Million Light Years
Galaxies: M65 (Top Right), M66 (Bottom Right) and NGC3628 (Bottom Left) also known as The Hamburger Galaxy or Sarah’s Galaxy

M81 and M82 Bodes Galaxy and Cigar Galaxy in LHaRGB

After much waiting, I finally have the RGB Data to go with the luminance layer, a new learning curve was the HDR Compose process in PixInsight, I used this to include the 300S Exposures I had previously that were burning out the core.

Equipment Used:
Imaging Camera: Qhyccd 183M Back Illuminated ColdMOS Camera at -20C
Imaging Scope: Sky-Watcher 8″ Quattro F4
Mount: Sky-Watcher EQ8 Pro
Guide Camera: Qhyccd QHY5L-II
Guide Scope: Sky-Watcher 90×50 Finder
Filter Wheel: Starlight Xpress Ltd 7x36mm EFW
Filters: Baader Planetarium LRGB + 7nm Ha
Image Acquisition: Main Sequence Software SGPro
Image Processing: PixInsight

Image Details:
101x150S in LRGB, Total 16.83 Hours
25x300S in LRGB, Total 8.33 Hours
25x600S in Ha, Total 4.16 Hours
Total exposure time: 29.32 Hours
BIAS, Darks and Flats subtracted
Target: M81 and M82 in Ursa Major
Acquisition Dates: Feb. 11, 2018,  Feb. 12, 2018,  Feb. 16, 2018,  Feb. 23, 2018,  Feb. 24, 2018,  March 13, 2018,  March 14, 2018,  March 15, 2018,  March 16, 2018,  March 19, 2018,  March 20, 2018

M97 / NGC3587 – Owl Nebula in LHaRGB

I have imaged this before in the same frame as the Surfboard Galaxy, however the 0.62 Arcseconds Per Pixel the Qhyccd 183M gives me on my Sky-Watcher Quattro 8″ F4 gives me a much higher resolution image, so here it is, the Owl Nebula in the constellation of Ursa Major at a distance of 2030 Light years from Earth

Gear:
Imaging Scope: Sky-Watcher Quattro 8″ F4 Imaging Newtonian
Imaging Camera: Qhyccd 183M 20mpx ColdMOS Camera at -20C and DSO Gain
Mount: Sky-Watcher EQ8 Pro
Guide Camera: Qhyccd QHY5L-II Mono
Guide Scope: Sky-Watcher 50×90 Finder Scope
Filter Wheel: Starlight Xpress Ltd 7x36mm EFW
Filters: Baader Planetarium 36mm RGB
Coma Corrector: Sky-Watcher Aplanatic Coma Corrector
Image Acquisition: Main Sequence Software SGPro
Image Processing: PixInsight

Image Details:
Target: M97/NGC3587 – Owl Nebula
Constelation: Ursa Major
Red: 27x300S
Green: 27x300S
Blue: 27x300S
Ha: 25x600S
Darks: 51x300S
Flats: 101
Bias: 251 converted to SuperBIAS and deducted from Flats
Imaging Dates: Feb. 12, 2018,  Feb. 16, 2018,  Feb. 24, 2018,  Feb. 25, 2018

PixInsight Image processing workflow:
1. Calibrated against darks and Bias Subtracted Flats
2. Star Alignment for all RGB and Ha Frames
3. Least noise frame from each colour chosen as Normalization Frame and Dynamic Background Extraction Performed
4. Normalization of all frames
5. Stacking of frames and generation of drizle data (for larger quality image in future)
6. Performed LinearFit using Red stacked image as reference for RGB Frames
7. Performed DynamicCrop on all channels and Ha
8. Performed MultiMedianTransformation to reduce background noise
9. Performed SCNR to remove excessive green in image
10. Stretched the image using HistogramTransformation
11. Performed an Unsharp Mask on RGB and HA Data
12. Performed an ATWT on the Background
11. Merged the Ha Data using the HaRVB-AIP Script in PixInsight
12. Performed a CurvesTransformation to bring out the star colour

M97 and M108 – Owl Nebula and Surfboard Galaxy in LRGB

M97 and M108

The Owl Nebula (also known as Messier 97, M97 or NGC 3587) is a planetary nebula located approximately 2,030 light years away in the constellation Ursa Major.  It was discovered by French astronomer Pierre Méchain on February 16, 1781

Messier 108 (also known as NGC 3556) is a barred spiral galaxy in the constellation Ursa Major. It was discovered by Pierre Méchain in 1781 or 1782. From the perspective of the Earth, this galaxy is seen almost edge-on.

The image consists of the following
23x180S – Red
23x180S – Green
23x180S – Blue
25x180S – Luminance

25 Darks, 25 Flats and 25 BIAS frames have also been applied

Equipment Used:-
Imaging Scope: Sky-Watcher Quattro Series 8-CF F4 Imaging Newtonian
Flattener: Sky-Watcher Aplanatic Coma Corrector
Imaging Camera: Atik Cameras 383L+ Mono CCD -20C
Guide Scope: Celestron Telescopes C80ED Reftractor
Guide Camera: Qhyccd QHY5L-II
Mount: Sky-Watcher EQ8 Pro
Filterwheel: Starlight Xpress Ltd 7x36mm EFW
Filters: Baader Planetarium 36mm Unmounted LRGB
Image Capture: Main Sequence Software SGPro
Image Stacking: Maxim-DL
Image Processing: PixInsight

Leo Triplet of Galaxies

Leo Triplet In LRGB (above) and LRGB+HA (below)

The Leo Triplet consists of three galaxies at a distance of around 35 million light years, M65 (top right), M66 (bottom right) and NGC3628 (left).  I have always aimed at imaging the triplet since I started imaging but never got around to it.

M65 (NGC 3623) and M66 (NGC 3627) are classed as intermiediate spiral galaxies and NGC3628 is also known as the Hamburger Galaxy or Sarah’s Galaxy and is classed as an Unbarred Spiral Galaxy.

The image consists of:-
29x300S of Luminance
14x300S Red, Green and Blue
15x600S of 7nm HA in the LRGB+HA Image
25 Darks and flats subtracted from all frames

Equipment Details:
Imaging Telescope: Sky-Watcher Quattro 8-CF F4 Imaging Newtonian
Imaging Camera: Atik Cameras 383L+ Mono CCD
Coma Corrector: Sky-Watcher Aplanatic Coma Corrector
Guide Camera: Qhyccd QHY5L-II
Guide Scoope: Celestron Telescopes C80ED Refractor
Mount: Sky-Watcher EQ8 Pro
Filter Wheel: Starlight Xpress Ltd 7x36mm USB EFW
Filters: Baader Planetarium LRGB + 7NM HA

Image Aquisition: Main Sequence Software SGPro
Image Pre-Processing and STacking: Maxim-DL
Post Processing: PixInsight

In my opinion, there’s only a subtle difference between the LRGB and LRGBHA images, personally I preffer the LRGB Version, the data was captured over multiple nights since the beginning of 2017 but in total gives 5.91 Hours on the LRGB Image and 8.41 Hours for the LRGB+HA Image