Markarians chain

[Rob63]

End of the season for me as Astro dark is getting too short so I thought I'd end with Markarians chain.

The weather has been awful this season but the last month has had quite a few good nights (where were they when I had more than 12 hours of astro darkness per night!)

ED80 + 0.85x reducer on an ED6-R Pro, ASI1600MM camera and Astronomik LRGB filters, Bortle 6/7 skies 

3 hours Lum and around 1.5 hours for each RGB filter.

I have added an annotated (via pixinsight) image to highlight the fantastic richness of this target

[Nik271]

Stunning, Rob, what a fabulous image!

[scotty38]

That's great and I tried my hand on this target a few nights ago. I'm using OSC but would you be able to share your Pixinsight workflow please? I'm still in the trial 45 days but would be great to see if I can make my image anything like yours and although I'm in Bortle 4 I suspect I may need a bit more data regardless.

For comparison and you'll see why I'm asking. BTW don't be misled, my image is further down this thread....

Thanks in advance 🙂

 

Edited April 19, 2021 by scotty38

[irtuk]

When you say 2 hours Lum, what is "Lum" ? is that the fourth filter that came in the RGB set?

Sorry for the daft question. I only got my camera bundle a couple of days ago.

amazing image btw!

 

Edited April 19, 2021 by irtuk

[scotty38]

It's the Luminance filter so yep most likely the 4th in a LRGB set...

[irtuk]

Ah! I wondered what that was for! so, where I have captured an hour each of R, G and B on my M101, I should also add to that a few hours of Luminance?

that might go some way to explaining the trouble I am having processing.

[peter shah]

beautiful colour an detail

 

[Rob63]

1 hour ago, irtuk said:

Ah! I wondered what that was for! so, where I have captured an hour each of R, G and B on my M101, I should also add to that a few hours of Luminance?

that might go some way to explaining the trouble I am having processing.

With a mono camera a Luminance filter is used for detail / sharpness and RGB for colour. Typically if you have light pollution you would use an LP filter for your Lum.

[geeklee]

Lovely shot Rob and good colour.  Loads to enjoy in the FOV.

2 hours ago, Rob63 said:

The weather has been awful this season but the last month has had quite a few good nights (where were they when I had more than 12 hours of astro darkness per night!)

Absolutely.  I have this vague memory of setting up and imaging by 6pm for 10-11 hours!  That didn't happen often mind...  Seems so long ago now  

[Rob63]

5 hours ago, scotty38 said:

That's great and I tried my hand on this target a few nights ago. I'm using OSC but would you be able to share your Pixinsight workflow please? I'm still in the trial 45 days but would be great to see if I can make my image anything like yours and although I'm in Bortle 4 I suspect I may need a bit more data regardless.

For comparison and you'll see why I'm asking. BTW don't be misled, my image is further down this thread....

Thanks in advance 🙂

 

Hi Scotty

I can't say I have any fixed workflow (and most of my stuff is narrowband rather than LRGB) but it was along the lines of:

Stacked in APP (I prefer APP when I have data from multiple sessions)

Lum
Dynamic crop
DBE
TGVDenoise
HistogramTransformation (multiple small stretches)

RGB (each channel)
Dynamic crop
DBE
ChannelCombination (to produce an RGB image)
PhotometricColorCalibration
HistogramTransformation (multiple small stretches)
Curves

LRGBCombination -> now I have LRGB image
LocalHistogramEqualization

Export to Photoshop
Adjust contrast, colour and saturation to taste

 

I recommend checking out Chris Woodhouse and Adam Block on YouTube for some great Pixinsight tutorials and also Chuck's astrophotography

 

Good luck.

Rob.

[scotty38]

That's great and very useful thank you. As a beginner to this tool I may have what is a beginner question. I see you do multiple small stretches with the histogram transformation process but I just use STF and then apply that to the histogram process and back to the image. Is that a "mistake"? 🙂

[Rob63]

42 minutes ago, scotty38 said:

That's great and very useful thank you. As a beginner to this tool I may have what is a beginner question. I see you do multiple small stretches with the histogram transformation process but I just use STF and then apply that to the histogram process and back to the image. Is that a "mistake"? 🙂

Hi Scotty,

It's the way everyone starts off (myself included) but as you gain experience you will want to have more control and refinement over the stretching as every image differs. 

You should download the excellent data provided by IKO for practice with high quality images, and check out people's submissions as a lot of them will outline their workflow.

 Rob.

 

[scotty38]

Thanks again. I did try the IKI data a couple of months ago when I first downloaded Pixinsight (I asked for a trial extension which is why I still have it) but couldn't even get it to appear in colour to start with. I posted my first attempt I think and then also last month's but since the first try I have just played around in Affinity which I already had for normal pictures. I have since decided I will stick with PI though hence why I'm trying a bit harder this time...

If it's just an experience thing I'll stick with the simple method for now until I get more familiar with it. Funnily enough when first using PI I wasn't aware of the WBPP script so you can probably imagine how much easier that made things when I did find it 🙂

Edited April 19, 2021 by scotty38

[bob-c]

A lovely image.

 

Bob.