Getting the best FWHM in your images is something that I have struggled with when imaging a whole night. As the temperature fluctuates, so does the FWHM in your images, this was a problem I had with my images at the beginning of the season. I looked around and the only focuser I could find was not a stepper motor focuser, so it didn’t offer predictable results. Since I am using the stock focuser for my Sky-Watcher Quattro 8-CF (and it’s a solid focuser at that), I did not really want to change focuser mid-season, so I did some research and landed upon the PrimaluceLabs Sesto Senso ROBO Focuser.
Now my expectations here were pretty low since I tried an electronic focuser and tried to use some sort of Auto Focus routine without any length of success, but when the Sesto Senso arrived I was excited as I looked at it and thought to myself that this would do the job.
Out of the box the Sesto Senso is very solid, good quality feel to it, and came with a bunch of different adapters for different focusers, one specifically for my Sky-Watcher Focuser too. I read the installation instructions a couple of times and set to work on upgrading my scope.
Installation Installation was fairly easy and straight forward, I removed the slow focusing knob off the focuser and attached the adapter for the Sky-Watcher that came with the Sesto Senso, so within 30 minutes it was successfully fitted. And I can still manually focus with the fast focusing knob on the other side of the focuser:
After all the physical installation was done, I then needed to install the software on the observatory PC, since I image using Sequence Generator Pro, I proceeded to install Sesto Software and the ASCOM driver so that SGPro could talk to the focuser, again this was relatively simple to do. Once this was completed it was important to load up the Sesto software and perform a calibration so that the Sesto Senso knows where the most innner and outer focus positions are.
Setting the Focus Control module in SGPro was a breeze, for this I used a Focusing Mask to get a rough focus and set that point for all of my filters, now the following setting are what works for me really well, but basically:
I use 20 data points to achieve focus.
Step size between focus points is 20
Focus frame is 10 seconds for all filters, this is to get a better normalised focus frame, I was finding 5 seconds was too short and gave un-predictable results.
I set it to re-focus after a temperature change of 3.0 Degrees C since the last focus.
I re-focus on any centering action which is useful if you use a mirrored telescope like me.
Sequence Generate Pro Auto Focus settingsYou can see here that my start off point is 50146, so it will go 10 points either direction of this point at 20 steps per point
I have now been using the Sesto Senso for a few months now and it has not failed me, I maintain a good FWHM value throughout the night and it an awesome piece of kit, well done Primaluce Labs. Is there anything that I would change about it?
Only one thing…….It requires separate power, which in all honesty I can understand why but if I could run the power through USB that would be a bonus.
One problem I have with the Auto Focus routine in SGPro is that in the image sequence, since my filters for LRGB are all parfocal, but my Narrowband filters are not, I only wish to focus on a filter change if it’s going from LRGB to Narrowband to LRGB or Narrowband to Narrowband, unfortunately SGPro doesn’t have that intelligence in the sequence, I am trying to persuade Jared to have that in there to make life that bit more simple.
Anyway I hope this review inspires you to consider this awesome piece of kit, it’s certainly helped me!
This object is a little tricker for me since I only have a 3-3.5 hour window per evening due to trees and the house blocking my view, this is also the first image that I used the drizzle function within PixInsight to be able to provide a detailed up close version of the image, I was very happy to have captured the brown “Globules” within the nebula to
Crescent Nebula in SHO NarrowbandSame object but with a 2x drizzle function in PixInsight applied
Image Details: Red Channel – SII Data – 89x300S Green Channel – Ha Data – 64x300S Blue Channel – OIII Data – 109x300S
101 Darks, Flats and BIAS Frames used
Equipment Used:- Imaging Camera: QHY183M Mono ColdMOS Camera at -20C Imaging Scope: Skywatcher Quattro 8″ F4 Newtonian Guide Scope: Skywatcher Finder Scope Guide Camera: QHY5L-II Mount: Skywatcher EQ8 Pro GEM Mount Focuser: PrimaluceLabs ROBO Focuser Filterwheel: StarlightXpress 7x36mm EFW Filters: Baader 7nm Ha, SII and OIII Acquision Software: Main Sequence Software Sequence Generator Pro Processing Software: Pixinsight 1.8.5
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
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
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
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
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
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
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
My first RGB Image from the Qhyccd 183M 20mpx Back Illuminated ColdMOS Camera, so here’s what I hope is one of many images taken with this awesome camera
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: IC434 – Horsehead Nebula
Constelation: Orion
Red: 19x300S
Green: 19x300S
Blue: 19x300S
Darks: 51x300S
Flats: 101
Bias: 251 converted to SuperBIAS and deducted from Flats
Data acquired on: Feb. 9, 2018, Feb. 11, 2018, Feb. 15, 2018
PixInsight Image processing workflow:
1. Calibrated against darks and Bias Subtracted Flats
2. Star Alignment
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
7. Performed MultiMedianTransformation to reduce background noise
8. Performed SCNR to remove excessive green in image
9. Stretched the image using HistogramTransformation
10. Performed a CurvesTransformation to bring out the star colour
Right now I have not performed any Sharpening of the image, nor have I added the Ha data to this image, I’ll post an updated image when I get round to doing that
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
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
