The EQ3 DSO Challenge

[Stub Mandrel]

7 minutes ago, mikey2000 said:

Sadly, I missed focus slightly

Still a good catch!

[mikey2000]

Thanks!

 

One think I have noticed with longer subs is that my stars are tending to be totally saturated to white in the centre with only the edges and spikes showing any of the original colour.

 

Am I getting into the realm of combining multiple exposures?  The 'wanderer' shot was from 4min subs at ISO400 F5.   I miss having nice red, orange and yellow stars in my pics :-(

[Stub Mandrel]

What I do is duplicate my stacks and process one for lumininosity and one for RGB. This means you can mess with the colour of the luminosity one to get the best detail, sometimes boosting just the red to give 'fake Ha' helps bring out a nebula for example. I usually blur the RGB one, as this gets rid of noise and makes the colours more even, but also can help spread the colours into the centre of stars, but it struggles for big stars

After my 100ISO experience I'm considering taking some shorter subs just to capture the star colours, and use this as an extra layer though.

[Filroden]

If you use Photoshop then Noel's Actions can enhance star colours by drawing in the outer colour into the saturated core. In PixInsight there is a way to achieve the same result using MorphologicalTransformation but having found it once, I've never been able to find it again!

[wimvb]

1 hour ago, Filroden said:

If you use Photoshop then Noel's Actions can enhance star colours by drawing in the outer colour into the saturated core. In PixInsight there is a way to achieve the same result using MorphologicalTransformation but having found it once, I've never been able to find it again!

HSV repair script. It's under scripts -> utilities. You can combine them in the linear stage, or (masked) stretch the V before combining.

Star reduction (morphology transform -> morphological selection) with contour mask can also give more star colour.

[Filroden]

21 minutes ago, wimvb said:

Star reduction (morphology transform -> morphological selection) with contour mask can also give more star colour.

That's the one. I found it did work well at both reducing the star and enhancing its colour. I didn't know about the script so I'll give it a try tonight. Thank you!

[Stub Mandrel]

I find that the 'Noels Action' works, but can also increases teh saturation so there's a limit to how many times you can run it.

[wimvb]

1 hour ago, Filroden said:

That's the one. I found it did work well at both reducing the star and enhancing its colour. I didn't know about the script so I'll give it a try tonight. Thank you!

Alejandro Tombolini has worked examples at pixinsight.com.ar that show how to use the script. I use it after dbe and background neutralization, but before colour calibration, since it will affect white balance. Then I follow up with deconvolution of stars only, before stretching. If you mask stretch the V channel, you end up with plenty of colour in the stars.

[mikey2000]

5 hours ago, Stub Mandrel said:

What I do is duplicate my stacks and process one for lumininosity and one for RGB. This means you can mess with the colour of the luminosity one to get the best detail, sometimes boosting just the red to give 'fake Ha' helps bring out a nebula for example. I usually blur the RGB one, as this gets rid of noise and makes the colours more even, but also can help spread the colours into the centre of stars, but it struggles for big stars

After my 100ISO experience I'm considering taking some shorter subs just to capture the star colours, and use this as an extra layer though.

I'm probably being thick but can you expand on how to process two different versions, one for Luminance, one for RGB?   I suppose that means starting from one .FTS file (ie, a DSS output file) and making two different versions?  Then re-layer them in photoshop?

 

I have a Photoshop CC subscription   - I'm sure I could try Noels Action (but I think it's only available as part of a package)  I wonder if there is a trial version - I will find out for sure!

[mikey2000]

I've revisited my astrotools processing.  I think I can get control over the saturation problem.

 

I finally got around to processing some pics I took a few nights ago while still battling with autoguiding.  I found 'C50 Satellite Cluster' in Stellarium in just the right spot in the sky for me and fired off 10x3 mins and was delighted to discover the Rosette Nebula.  Totally unexpected at just 30mins with an unmodded camera. (Image stretched to pieces....)  And to finish up. M44 - The Beehive Cluster

 

 

[wimvb]

Nice catch. The Rosette Neb will be a challenge for an unmodded camera. If you have the possibility to increase the exposure time and number of exposures, that will really help to pull out more detail. Otherwise the nebula will stay close to the noise floor.

What processing software do you use. To enhance the nebula and keep the stars under control, you can use either Masked Stretch in PixInsight, of a similar technique in PS/GIMP

http://www.nightanddayastrophotography.com/gallery/Processing.htm

Especially nr 12: LMS (Layered, Masked Stretch) processing

Thanks for sharing

[mikey2000]

Thanks Wim,

 

I'm using DSS to process my raw files then into Startools.  I used Photoshop and Lightroom on the end result.  I did once try a trial of Pixinsight but it expired way before I had a clue what I was doing.  I was really astounded to see the rosette nebula - I thought I'd need much longer!

 

This whole DSO imaging thing is a fascinating learning curve.  Right now, I'm gathering some Whirlpool data to compare 2min vs 4min subs under a half-moon sky with a Baader neodyium filter to investigate the SNR differences between 'short' and 'not so short' subs.

[Peco4321]

12 hours ago, mikey2000 said:

with an unmodded camera.

That's an amazing picture, simply breathtaking. What camera are you using. 

[Stub Mandrel]

11 hours ago, wimvb said:

http://www.nightanddayastrophotography.com/gallery/Processing.htm

I had to stack 50 subs of that website and do a stretch before I could read it...!

[mikey2000]

7 hours ago, Peco4321 said:

That's an amazing picture, simply breathtaking. What camera are you using. 

Thanks!   I had to do an awful lot of PP  - you can still see plenty of red dots in there -  I couldn't get them all :-)  I'm using a Sony A6000 unmodded (mirrorless APS-C 24mpix) and a baader corrector and neodyuim filter.   I'm pleased!

[wimvb]

6 hours ago, Stub Mandrel said:

I had to stack 50 subs of that website and do a stretch before I could read it...!

Blair MacDonald had an article in the Canadian astronomy society's periodical about this. It's available online, and easier to read.

[Stub Mandrel]

1 hour ago, wimvb said:

Blair MacDonald had an article in the Canadian astronomy society's periodical about this. It's available online, and easier to read.

http://adsabs.harvard.edu/full/2011JRASC.105...34M

[johnfosteruk]

Posted in the wrong thread

Edited April 6, 2017 by johnfosteruk

[bobro]

Somehow the Moon always seems to be out when it's time to test something......this time my Raspberry PI/Lin_guider dual axis autoguiding config has been replaced by PHD2 running on the image capture laptop. The main reason for this was to simpify the setup with the laptop now running guiding and image capture. It also makes for a simpler battery powered dual axis guided setup : camera battery, RA motor battery (PP3) and laptop battery. The laptop is actually an eebook, but seems to handle guiding and image capture without issue. The eebook very long battery life of 8-10 hours is excellent, though it will be reduced a bit due to driving the DEC motor and the Arduino.

The first image (Jupiter - below) with the new setup is 14 subs each of 180 seconds, 100ISO due to the Moon. Guiding seemed to work ok - not much different from Lin_guider except for guiding corrections issued less frequently. This could be an issue when the wind gets up a bit.

Looking forward to a better imaging test when there isn't a moon!

[Stub Mandrel]

6 hours ago, bobro said:

The first image (Jupiter - below) with the new setup is 14 subs each of 180 seconds,

Cripes, I image Jupiter at 30fps!

[bobro]

4 hours ago, Stub Mandrel said:

Cripes, I image Jupiter at 30fps!

Must get an upgrade for my camera! 

[bobro]

Anyone know why the global Sky-Watcher site shows the EQ3 with a steel tube tripod http://www.skywatcher.com/product/eq3-synscan/ , yet (in the UK at least), it is sold with the aluminium tripod that doesn't seem great for stability?

[Nigel G]

4 hours ago, bobro said:

Anyone know why the global Sky-Watcher site shows the EQ3 with a steel tube tripod http://www.skywatcher.com/product/eq3-synscan/ , yet (in the UK at least), it is sold with the aluminium tripod that doesn't seem great for stability?

No idea, it looks like all the outlets sell with the aluminium tripod.although it specifies the stainless steel type. 

[Stub Mandrel]

The Evostar 90 on EQ3-2 seems to come with a steel tripod

[Peco4321]

Had a great night on Saturday finding 3 new objects for me, M3, M53 and The Blackeye Galaxy. I managed to image all 3 to varying degrees of success, my focus was out on both global clusters unfortunately so stacking produced pretty rubbish results although a single sub of 30 seconds with a passing satellite is quite pleasing. 

Blackeye galaxy was a bit better so here's 20 x 30 secs ISO 800, 10 x bias stackedypp in DSS and stretched a bit in GIMP. One of these days I'll get data over an hour!!