Tag Archives: OIII

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

IC36 Y Cas Nebula in SHO

Located in the constellation of Cassiopeia this rather feint nebula is illuminated by a very bright Magnitude 2.15 star Navi

Image Details:
101x300S in SII – Red Channel
101x300S in Ha – Green Channel
101x300S in OIII – Blue Channel

Total integration time: 25.2 Hours

101 Darks, Flats and Dark Flats applied

Acquisition Dates: Oct. 27, 2018, Dec. 13, 2018, Dec. 27, 2018, Jan. 1, 2019, Jan. 2, 2019, Jan. 4, 2019, Jan. 8, 2019, Jan. 9, 2019, Jan. 11, 2019, Jan. 18, 2019, Jan. 20, 2019, Jan. 23, 2019, Jan. 27, 2019, Jan. 28, 2019, Jan. 30, 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 Ha, SII and OIII
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

NGC6888 – Crescent Nebula in SHO Narrowband

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 Narrowband
Same 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

NGC2264 – Cone Nebula in SHO Narrowband

My latest image, I feel like I need more SII and OIII Data though to be perfectly honest, I captured quite a lot of dust even with narrowband mainly due to the high amount of HA frames I suspect, well here it is

Image Details:
27x 600S in 7nm HA
18x 600S in 7nm OIII
18x 600S in 7nm SII

25 Darks and Flats subtracted from lights

Data was acquired on the following dates: 18th, 19th, 20th and 21st January 2017, 13th and 18th February 2017

Equipment Used:
Imaging Scope: Sky-Watcher​ Quattro 8-CF Imaging Newtonian @F4 with the Skywatcher Aplanatic Coma Corrector
Imaging Camera: Atik Cameras​ 383L+ Mono CCD Cooled to -20C
Guide Scope: Celestron Telescopes​ C80ED Refractor
Guide Camera: Qhyccd​ QHY5L-II Mono
Mount: Sky-Watcher EQ8 Pro
Filter Wheel: Starlight Xpress Ltd​ 7x36mm EFW
Filters: Baader Planetarium​ 7nm HA, OIII and SII 36mm Unmounted
Image Acquisition: Main Sequence Software​ SGPro
Stacking and Combining: Maxim-DL
Processing: PixInsight​

Atik 383L+ Cooled Mono CCD Imaging Camera

After owning the Atik 383L+ Mono CCD Camera for over three years now, I would say I am definitely qualified to write a review.  I bought my camera back in 2013 when I lived in Ireland it was during the time when I transitioned from imaging with a Cooled and Modified DSLR Camera to Mono CCD Imaging.  At the time I was considering one of two cameras, the QHY8 Mono CCD and the Atik 383L+ Mono CCD, at the time the QHY was slightly cheaper but the Cooling Delta and Readout Noise was better on the Atik despite the fact that they both used the Kodak KAF8300 chip.

When I first received my camera, I was thoroughly impressed with the build quality, the red aluminium casing gave it a really professional feel to the camera and came complete with USB Cable, 12v Cigarette Power Cable and Software Media, all packaged really well, and when taking the camera out of the box, you could tell that Atik had put a lot of effort and consideration into their build quality and finish of the camera.  So far so good!

People quite often ask me how big the camera is, it just so happens that at the time I got my camera, I took a picture of the camera next to a AAA battery, just for comparison you can see that it is a fairly compact camera and at around 700g wasn’t too heavy either.

Because I couldn’t wait until my filterwheel had arrived, I wanted to test the camera functionality, so I installed all of the software onto my desktop PC and plugged the camera in.  At the time I got the camera, I was using Nebulosity to perform my image acquisition, so the first thing to do was build my dark frames at my desired temperature of -20C.  The dark frames showed very little in the way of noise which I was extremely happy with.  The installation of Drivers and  ASCOM Platform drivers all went perfectly without any problems, and Nebulosity worked well using the ASCOM Camera platform driver.

Once my filterwheel had arrived from StarlightXpress it was time to get the camera aquainted with the telescope, and at the time I was using an Astro-Tech 8 Inch Ritchey Chretien telescope on my already 3 Year Old NEQ6-Pro mount. Mating the camera to the filterwheel was relatively easy, I placed a thin cork shim onto the male thread of the filterwheel and screwed the camera on and adjusted the rotation of the filterwheel adapter to make sure the camera was at the right angle, I used the rubber shim to stop the metal to metal binding which makes it difficult to remove later, adding in the cork shim still allows it to be tightened up.

Since I had built my dark frame library, it was time to build my flat frames library, for this I used an EL Panel, one of the things I noticed was that a short exposure time of <1.0 seconds left a dark area to the lower right of the frame, after speaking with Atik they confirmed it was just the mechanical shutter, so I had to reduce the light on the EL Panel in order to increase the exposure time to get around this, other than that my flat frame library was built.

My first light for the camera was going to come from NGC7635 – Bubble Nebula in Narrowband, and whilst I must admit my imaging has come a long way since I took this picture, it is what it is and I was very happy with the results of sensitivity the camera delivered especially as this image is only 3x1800S frames for HA, OIII and SII.  Since I have had the camera, I have produced a substantial number of images to date and continue to do so using my Atik 383L+ Mono CCD Camera.

So how does Atik fair with me as a company, well it just so happens that I had to send my camera away for service due to excessive moisture causing Ice Crystals during cooling, I filed a support ticket with them and within a few days I got my camera back completely moisture free, I do not blame the camera here for the moisture, but more the fact that when I had my observatory located 15 miles away, I used to forget to switch the camera power off which would push a lot of moisture through the camera.  But the service from Atik was simply awesome.

Here’s a picture of the camera still used today attached to my F4 Quattro, I use Sequence Generator Pro for all my target acquisitions today but still using the ASCOM Camera Driver which is extremely stable

Just to recap why I am happy with the camera:

  • Build Quality
  • Size and Weight
  • Software Deployment
  • Sensitivity
  • Quietness of the camera

What could have been better?

  • Power cable – This could have been a stretchable power cable as I did run into a problem recently where the cable became snagged and it ripped the wire out of the jack plug that plugs into the camera, fortunately it didn’t damage the plug in port of the camera
  • Heated chip chamber, most cameras seem to have this now
  • Different colour options – I would have loved the camera in Blue or Green

You can see many of the images I have taken with this camera in my CCD Image Gallery Section here

 

 

NGC281 – Pacman Nebula in Hubble Palette Narrowband

NGC281 – Pacman Nebula

NGC 281 is located in the constellation of Cassiopeia and part of the Perseus Spiral Arm. It includes the open cluster IC 1590, the multiple star HD 5005, and several Bok globules. Colloquially, NGC 281 is also known as the Pacman Nebula for its resemblance to the video game character.

The Image consists of
21x600S in SII – Mapped to Red
21x600S in HA – Mapped to Green
21x600S in OIII – Mapped to Blue
25 Darks and Flats

The HA Channel was also used as a Luminosity layer

Equipment Used
Mount: Sky-Watcher EQ8 Pro
Imaging Camera: Atik Cameras 383L+ Mono CCD Cooled to -20C
Imaging Scope: Sky-Watcher Quattro 8-CF 8″ F4 Newtonian
Coma Corrector: Sky-Watcher Aplanatic Coma Corrector
Guide Camera: Qhyccd QHY5L-II
Guide Scope: Celestron Telescopes C80ED Refractor
Filter Wheel: Starlight Xpress Ltd 7x36mm EFW
Filters: Baader Planetarium 7nm HA, OIII and SII 36mm unmounted

Software Used:
Image Acquisition: Main Sequence Software Sequence Generator Pro
Guiding: PHD2
Stacking and Pre-Processing: Maxim-DL
Post Processing: Photoshop, Noise Ninja

IC1396 – Elephant’s Trunk Nebula in Hubble Palette Narrowband

IC1396 – Elephant’s Trunk Nebula in Hubble Palette Narrowband

Image consists of
15x 600S – 7nm HA
15x 600s – 7nm OIII
15x 600s – 7nm SII

HA Layer was also used as Luminance and Overlay layer

All data was obtained over five nights, 7th and 8th September 18th September, 22nd September and 23rd September 2016

Equipment Used:
Imaging Scope: Sky-Watcher Quattro 8-CF 8″ F4 Newtonian
Guide Scope: Celestron Telescopes C80ED
Imaging Camera: Atik Cameras 383L+ Mono CCD Cooled to -20C
Guide Camera: Qhyccd 5L-II
Mount: Sky-Watcher EQ8 Pro
Capture Software: Main Sequence Software Sequence Generator Pro
Guide Software: PHD2
Dark/Flat Subtraction and Stacking: Maxim-DL
Post Processing: Photoshop

To date I think this is my best image so far, I am very happy with the results of the image and the colour balance obtained