Page 1 of 1

NGC 7293 Helix Nebula OSC Narrowband Bi Color

Posted: Sat Aug 14, 2021 12:06 pm
by Startrek
Captured around 4 hours over 2 nights on the Helix planetary nebula using my 8”f5 GSO newt and ZWOASI2600MC set in Ascom to Highest Dynamic Range Gain 0
It’s only my second time imaging this object
Loaded data set in Compose and used OSC / DSLR Bi Color preset , then Linear
In Color module used the matrix and tried some different OH , HO OOH versions to create a few Bi Color blends
Tracking and Goto EQMOD and Ascom Stellarium
PHD2 Multistar guiding at 0.60 to 0.65 arc sec error total
Captured in APT
Stacked in DSS

Thanks for looking
Comments most welcome

Re: NGC 7293 Helix Nebula OSC Narrowband Bi Color

Posted: Sat Aug 14, 2021 8:17 pm
by ionia23
The word I would use to describe this is "overwhelming". I'm mesmerized by the sharp detail in the center of what is not a particularly large object.

You said that you used an 8" reflector (kind of like mine) for capturing this object. One of the things I've been struggling with when it comes to my own camera is the field of view is fairly small. I've been able to estimate that my own camera on my 203mm reflector shooting in prime focus is an immediate magnification of just about 100x without any of the side effects of magnification you see using eyepieces.

How does yours do for a general field of view? And I may have missed it in the original post, how many light frames did you have in the final stack?

Re: NGC 7293 Helix Nebula OSC Narrowband Bi Color

Posted: Sat Aug 14, 2021 10:34 pm
by Startrek
Thanks for the nice comments
Appreciate it
Here’s. How you calculate field of view FOV in imaging

FOV for Imaging
Camera sensor size mm x 3460 divided by telescope focal length

ZWO ASI2600MC Sensor 23.5mm x 15.7mm
8” f5 GSO newtonian reflector 1000mm focal length

FOV
23.5 x 3460 / 1000 = 81 arc mins
15.7 x 3460 / 1000 = 54 arc mins

If use Stellarium or other planetariums it tells you what size your intended object is in arc minutes , then you assess whether the object is too small or too big for your rigs FOV
As far as detail is concerned , the 2600MC is a very good camera with exceptional dynamic range and low noise
Startools does the rest in processing to bring out the detail
My capture consisted of around 60 x 4 minute dithered guided subs

Thanks again
Clear Skies

Re: NGC 7293 Helix Nebula OSC Narrowband Bi Color

Posted: Sun Aug 15, 2021 12:58 am
by ionia23
You're most welcome. You definitely deserve the praise for the quality of this shot. It also goes to show that I received some pretty bad advice early on in my adventures in astrophotography. I need more light frames (I never did more than 20). That will probably help a great deal. Like the say, it's much easier to start working with good data than trying to fix bad data.

Exceptional job.

Re: NGC 7293 Helix Nebula OSC Narrowband Bi Color

Posted: Sun Aug 15, 2021 2:16 am
by Startrek
I use a $500 low end budget GSO solid metal tube newt
What allows me to produce these reasonable images is my camera without a doubt
My ZWOASI2600MC cooled OSC camera is the latest generation cmos with the Sony IMX571 backlit sensor (high end stuff ) cost me $3,300 Aus
I’ve had this camera for nearly a year and it’s unbelievable ( prior to this I was using a Canon 600D T3i DSLR for 3 years , man this new camera is like comparing a E class Mercedes Benz to a 1965 VW Volkswagen , chalk and cheese )
From my limited experience in AP ( 5 years ) , you don’t need an expensive scope in AP , my advice is to put your money into a good quality mount and good quality cooled camera OSC or Mono
Clear Skies

Re: NGC 7293 Helix Nebula OSC Narrowband Bi Color

Posted: Tue Aug 17, 2021 10:38 pm
by Mike in Rancho
These are really striking images!

You said bicolor, so was a duoband filter used? And it seems like I see multiple colors in each version. A little confusing, I thought that opening as duoband from OSC/DSLR and then the bicolor mappings were supposed to keep things to two color hues, or two main hues?

Re: NGC 7293 Helix Nebula OSC Narrowband Bi Color

Posted: Wed Aug 18, 2021 12:22 am
by Startrek
I use the Optolong LExtreme OSC NB filter

I load my data set in Compose to RGB ( not Luminance ) and set Color to OSC / DSLR Bi Color
Then in Colour module use the Matrix ( bottom right ) with different SHO options , all I do is back off the green bias a bit and adjust the red a tad ( leave the blue as is ) and you end up with various Bi colour versions as you scroll through the SHO options. The HO , OH and OOH options don’t work that well to produce Bi colours
I just experimented and stumbled across these neat Bi Colors

Re: NGC 7293 Helix Nebula OSC Narrowband Bi Color

Posted: Wed Aug 18, 2021 6:01 am
by Mike in Rancho
Startrek wrote: Wed Aug 18, 2021 12:22 am I use the Optolong LExtreme OSC NB filter

I load my data set in Compose to RGB ( not Luminance ) and set Color to OSC / DSLR Bi Color
Then in Colour module use the Matrix ( bottom right ) with different SHO options , all I do is back off the green bias a bit and adjust the red a tad ( leave the blue as is ) and you end up with various Bi colour versions as you scroll through the SHO options. The HO , OH and OOH options don’t work that well to produce Bi colours
I just experimented and stumbled across these neat Bi Colors
Yeah I think I've been doing the same thing, always load into compose and pick the DSLR bicolor. In the color module I usually hit the bicolor preset, which takes you right down to the first HOO in the list, below all the SHO variations. As I understand it, in the H/O bicolor schemes, the B and G are locked together anyway, so whether you choose the G or the B for the bias reduce, it's the same thing so you only need to adjust the one.

Those just really surprised me to be bicolors! :D