The "No EQ" DSO Challenge!

[parallaxerr]

I've been doing some trial & error testing with DSS and ST. Every "correct DSS settings for ST" thread I read suggests turning off RGB Background Calibration and Per Channel Background Calibration.

BUT, if I turn both of these calibration methods off, I seem to lose data in the developed image in ST. Pictures attached show the difference. Any ideas? I assume the orange glow to the non-corrected image is light pollution but as you can see there is less detail in M31, which further processing does not seem to be able to bring out.

[The Admiral]

31 minutes ago, alacant said:

Hi. I feel that you have less control over AutoDev than Dev. For me, the best way is to autodev first just to see what's there. Then after Wipe has done its gradient magic, use the Develop slider a bit at a time -a bit like seeing the print emerge in the old days of wet darkroom prints-. Just to the right of the slider there's a home-in- button which gets you a good approximatrion without overstretching. There's also dark anomaliy control and a chance to change rgb l values, something else you don't get with AutoDev. That way you have more control over the second stretch than by AutoDev without a mask. HTH.

**Î've a feeling we're gonna get thrown off this thread soon as I think we may have gone off topic. Me certainly.

Your workflow is the one I normally adopt, and I normally up the dark anomaly slider for wipe and develop. Just thought I'd give the Auto-Dev a go as Ivo seemed to extol its benefits.

Not sure why this isn't pertinent to No Eq, as I used an Alt-Az mount. Or were your asterisks left over from a previous post?

Ian

[The Admiral]

34 minutes ago, parallaxerr said:

I've been doing some trial & error testing with DSS and ST. Every "correct DSS settings for ST" thread I read suggests turning off RGB Background Calibration and Per Channel Background Calibration.

BUT, if I turn both of these calibration methods off, I seem to lose data in the developed image in ST. Pictures attached show the difference. Any ideas? I assume the orange glow to the non-corrected image is light pollution but as you can see there is less detail in M31, which further processing does not seem to be able to bring out.

Yes, the orange glow is light pollution, that's what I get. The purpose of WIPE is to remove that and to get rid of any gradients etc, but in order for wipe to work properly you need to crop the picture to get rid of the stacking artefacts which you can see around the edges (i.e. where field rotation is evident after stacking).

Then, after WIPE, you need to redo the global stretch, either by clicking Auto-Development, or Development and adjusting parameters yourself. I shouldn't think you'll be losing data through those DSS settings. By not cropping the image before WIPE you are getting a background and a gradient, which may be masking the target details. See what happens if you crop.

Ian

[Nigel G]

Ian,Its looking good, there's a variety of colours in there, it might be a touch over developed, have you tried the filter module in ST, it will help with removing noise.

Open filter, select reject, zoom in to noisy part and click on a colour pixel you want removed, this starts to remove the noise, the more pixels you click on it keeps removing. careful not to over do it though.

I use auto dev up to the wipe stage too. I also use Max RGB in the colour module to try and help with balancing the colours, It seems to help.

I had a look at that layering different exposures link. It looks good but I think we with alt-az mounts might struggle a bit with having to crop and the field rotation thing. I think it will be a lot of work trying to line up the images.

Nige. 

[parallaxerr]

1 hour ago, The Admiral said:

but in order for wipe to work properly you need to crop the picture to get rid of the stacking artefacts which you can see around the edges

Hi Ian, neither of those images have been wiped, just auto developed. This lead me to think there was less info in the one with no calibration.

HOWEVER, light bulb moment! I had previously NOT been re-stratching after wiping, because with colour calibrated images from DSS ended up with mega amounts of noise which washed out the detail. BUT, having just re-stretched a non-colour calibrated image, the detail came back   Thanks!!!

Still very noisy but the colours look much better without having been adjusted, so I think I'm making progress. Just need to work out where to go from here...

 

Edited October 13, 2016 by parallaxerr

[SteveNickolls]

2 hours ago, alacant said:

**Î've a feeling we're gonna get thrown off this thread soon as I think we may have gone off topic. Me certainly.

I would hope not-no one has said anything up front about matters as far as I know. It has become a very popular thread though hasn't it?

If it wasn't to pigeon hole us Alt-Az'ers more I'd ask for a separate Alt-Az Imaging section in SGL to keep the particular issues together and available for others to find and participate in. What this thread has done is to act as a focal point for a growing a body of like minded individuals who are up for experimenting with equipment and software and having a place to post their successes and issues, and importantly, discuss. If the posts were split up across SGL then I'd be asking for a place of our own. We are posting images and most importantly detailing our settings etc. so others can learn from them. Using StarTools for Alt-Az work is different from using EQ gear as we are touching on important issues around light pollution, the length and number of light frames, the point of using dark frames and the issues surrounding using and applying software to Alt-Az data. If it wasn't for Alt-Az imaging a number of people would never have taken the practical steps to get into astro-photography and be put off by the common but misconceived  view that you can't image with Alt-Az gear and so...

As a way of demonstrating the interlinked nature of Alt-Az working I'm posting an image of M51 that I have been able with the help of this thread to better utilise software (DSS and StarTools) over seven months to improve the final image-

First my earlier attempt-

And the same data after tweaks to DSS started and discussed on the thread (and also for StarTools)-

The data used 115 forty second light exposures at ISO 1600 plus x50 dark and x50 bias frames. At that point I had not been using flat frames as part of my learning curve. I used my SkyWatcher Startravel 102mm refractor on the Synscan alt-Az mount and Canon 600D DSLR.

You can still see the effects of local light pollution in the more recent image.

Ad Astra Guys,

Steve

Edited October 13, 2016 by SteveNickolls

[The Admiral]

2 hours ago, parallaxerr said:

Just need to work out where to go from here...

Have a look at this Google Hangout where Ivo takes you through StarTools. It's a long presentation, with glitches, and if you can stay awake there's some useful stuff which'll help you.

Ian

[happy-kat]

It's cloudy night discussion.

When I eventually found the first image the second I think is better, it's slight but is better. Looks less muddied there's more clarity... Just.

Edit: that was looking on tablet, here on PC the difference is stronger. I would like to see te image with a wider background if possible

Edit Edit I cannot recall when I last had a clear evening combine with getting outside

Edited October 13, 2016 by happy-kat

[parallaxerr]

7 hours ago, The Admiral said:

Have a look at this Google Hangout where Ivo takes you through StarTools

Go to top of the class Ian, what a great video! Having the program writer explain what each of the filters/modules are actually doing really helps to understand what's going on. I watched the tutorial with Ivo whilst re-working my M31. It's obvious I have shed loads of noise which is hard to get rid of, more subs and clearer skies required.

It's easy to forget what it is you're processing and I have to remind myself I captured it in my back garden, so, for my first fully processed attempt, I'm very pleased with this. Final post of M31 with these (poor) subs! Thanks to everyone for the guidance

 

[The Admiral]

I think you've done very well with that Jon. I'd be happy with it if it was mine.

Ian

[SteveNickolls]

On 10/13/2016 at 12:07, Nigel G said:

"...It looks good but I think we with alt-az mounts might struggle a bit with having to crop and the field rotation thing. I think it will be a lot of work trying to line up the images."

Nige. 

I've downloaded a trial version of BYEOS Nige and one of the things you can do (p30-31 of the BYEOS manual) is overlay the current imaging session with an image from a previous session to align everything up (called 'Mask Framing in BYEOS'). I haven't tried this yet but it might be worth investigating? As an alternative I have used DSS to combine the images from two sessions and it is very forgiving.

Cheers,
Steve

Edited October 14, 2016 by SteveNickolls

[SteveNickolls]

I've been playing on StarTools again and come up with a potential way of getting an image with a background clear of light pollution. It will work in images where there are just stars. I follow the process in the HEAL section of the StarTools 1.3.5 Unofficial User Manual (p 83 onwards) but use the extracted stars as the final image. What do folks think?

Here's an image of NGC 1502 taken on 15th August earlier this year (x20 forty five second light frames at ISO 800 plus x50 dark, flat and bias frames stacked in DSS and processed in StarTools). I used the SkyWatcher Startravel 102mm refractor on a Synscan Alt-Az mount and Canon 600D DSLR.

Image processed without the new process showing remaining evidence of light pollution-

And using the new procedure for comparison-

Regards,
Steve

Edited October 14, 2016 by SteveNickolls

[happy-kat]

Really interesting comparing those. There is a much smoother background with the second image it's lost the mottling noise. Be really interesting to see if you can do this but say on m31 as that might be tricky with how m31 is.

Thank you for sharing.

[alacant]

59 minutes ago, SteveNickolls said:

Startravel 102mm

Great shot. Nice technique. Even better colour. Who needs an apo?!

[SteveNickolls]

48 minutes ago, alacant said:

Great shot. Nice technique. Even better colour. Who needs an apo?!

He,he thanks, I was wondering that myself.  Might see more in the classifieds.

 

Cheers,
Steve

[SteveNickolls]

1 hour ago, happy-kat said:

Really interesting comparing those. There is a much smoother background with the second image it's lost the mottling noise. Be really interesting to see if you can do this but say on m31 as that might be tricky with how m31 is.

Thank you for sharing.

Hi, I'm unsure how a galaxy also being in the image would respond but there's really only one way to see :-) I've just re-stacked the origianl frames and processed an image of M35 from the 16th January 2016 using the same method, again just a shot with stars and clusters.

Here's the original image (from x30 ten second light frames at ISO 1600 plus x40 dark frames) at the time I hadn't got to he point of taking flat frames or bias frames. All exposures using the SkyWatcher Startravel 102mm refractor and Canon 600D DSLR on the Synscan Alt-Az mount-

At the time I hadn't known how to remove the purple halos around the brighter stars.

And after the new procedure, the image has been cropped more in the latest attempt this afternoon-

The smaller cluster at the four o'clock position  is NGC 2158.

Cheers,
Steve

[alacant]

47 minutes ago, SteveNickolls said:

remove the purple halos

We've a thread on the st forum about reducing the halos, not just in software. I found by accident that there are methods at the image acquisition stage too. On my modified canon the remaining filter is not enough to avoid the stars enlarging. The uv (or maybe it was the ir -tech stuff I don't understand) records as blue by the sensor. A filter will remove all the invisible radiation and in so doing all but remove the blue star halo. HTH.

[SteveNickolls]

24 minutes ago, alacant said:

We've a thread on the st forum about reducing the halos, not just in software. I found by accident that there are methods at the image acquisition stage too. On my modified canon the remaining filter is not enough to avoid the stars enlarging. The uv (or maybe it was the ir -tech stuff I don't understand) records as blue by the sensor. A filter will remove all the invisible radiation and in so doing all but remove the blue star halo. HTH.

Thanks for this alacant my camera has  standard uv filter on it when used for piggyback imaging is that what you mean? I'll take a look on the StarTools Forum too. I have tried removing the blue channel in the past and that can help.

Cheers,

Steve

[Nigel G]

4 hours ago, SteveNickolls said:

I've been playing on StarTools again and come up with a potential way of getting an image with a background clear of light pollution. It will work in images where there are just stars. I follow the process in the HEAL section of the StarTools 1.3.5 Unofficial User Manual (p 83 onwards) but use the extracted stars as the final image. What do folks think?

Here's an image of NGC 1502 taken on 15th August earlier this year (x20 forty five second light frames at ISO 800 plus x50 dark, flat and bias frames stacked in DSS and processed in StarTools). I used the SkyWatcher Startravel 102mm refractor on a Synscan Alt-Az mount and Canon 600D DSLR.

Image processed without the new process showing remaining evidence of light pollution-

And using the new procedure for comparison-

 

That's a vast difference in noise and clarity, nice  

The heal module is a great tool, removing stars to work on the background image, with dso's you just layer the stars back in after clearing the noise.

Priceless

Nige.

[alacant]

2 hours ago, SteveNickolls said:

is that what you mean?

Hi. No, not piggyback; in the telescope as you're imaging. It's a 2" filter you screw onto the nosepiece to which the camera is attached. I think uv is part of it but you also need to cut the ir, one stops the core of the star expanding, the other the blue halos. There's one filter which does both and controls the way the sensor sees the blue or uv or ir or some combination of them. I'm no expert so sorry can't be more specific, I'm away at the moment but there's a photo of it in the link I sent. HTH

Edited October 14, 2016 by alacant

[Nigel G]

Oh for a clear night sky, I sit here swirling and sipping a single malt thinking what I'd do for a whole night of clear sky's, the weather man says no clear sky's for the next 5 nights. I really hope he's wrong.

Doesn't he know we have lots of things to try....... I'm going to re process an image or 2 with the recent findings.

This will be my 3rd reprocessing, it is great to be able to go back and start again with anything from re stacking to final tweaking ( depending on weather you kept your sub's )

I hope your weather man is telling you better things.

Cheer's

Nige.

 

[alacant]

1 hour ago, SteveNickolls said:

6 minutes ago, Nigel G said:

no clear sky's for the next 5 nights

Could be worse; new moon. Pass the scotch...

[SteveNickolls]

1 hour ago, alacant said:

Hi. No, not piggyback; in the telescope as you're imaging. It's a 2" filter you screw onto the nosepiece to which the camera is attached. I think uv is part of it but you also need to cut the ir, one stops the core of the star expanding, the other the blue halos. There's one filter which does both and controls the way the sensor sees the blue or uv or ir or some combination of them. I'm no expert so sorry can't be more specific, I'm away at the moment but there's a photo of it in the link I sent. HTH

Thanks, I'll take a look at the filter. :-)

Cheers,
Steve

[SteveNickolls]

13 hours ago, Nigel G said:

Oh for a clear night sky, I sit here swirling and sipping a single malt thinking what I'd do for a whole night of clear sky's, the weather man says no clear sky's for the next 5 nights. I really hope he's wrong.

Doesn't he know we have lots of things to try....... I'm going to re process an image or 2 with the recent findings.

This will be my 3rd reprocessing, it is great to be able to go back and start again with anything from re stacking to final tweaking ( depending on weather you kept your sub's )

I hope your weather man is telling you better things.

Cheer's

Nige.

 

Hmm, the weather forecast here is pretty poor too, can only be consoled that it's a bright, full Moon. Plenty of old images to reprocess though. Can I ask which whisky you are sipping?

Cheers,

Steve

Edited October 15, 2016 by SteveNickolls

[Nigel G]

12 hours ago, SteveNickolls said:

Hmm, the weather forecast here is pretty poor too, can only be consoled that it's a bright, full Moon. Plenty of old images to reprocess though. Can I ask which whisky you are sipping?

Cheers,

Steve

Steve,  twas a Jura superstition I bought back from Scotland,  nearly empty now though

Very nice.

This image is s single shot single malt of around 15 years . No stacking or post processing just a drop of water to bring out the full flavour. 

I might have to sail back soon to get another one.  Well next summer anyway. 

Nige.