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Danjc

First Mono image the soul nebula with new version and now Flats help

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Posted (edited)

After purchasing my ASI183MM-Pro a few months ago this weekend was the first time I have gone out and had a go at actually capturing something. So a new camera as well as the mount having a new puck, saddle with everything re configured on a losmandy plate oh and it was also the first run out since I had belt modded the HEQ5 it was going to be an interesting night...…..

After getting everything working/sorted on the Sunday night I did manage about 45 min on the pacman.

last night I could just focus on capturing data so decided on the Soul nebula.... 24 300s lights in Ha. I have a slight bit of amp glow on the RHS but I reckon this is because my previously taken dark library was at unity gain (111) but I shot last night at unity gain (120) all the same temp and length, other calibration frames included flats and dark flats.

@Adam J I defiantly made the right choice going mono, Cheers 👍🏻

 

Feedback and criticism welcome.

1464899254_SoulNeb.thumb.jpg.191aa7a1e88b70d92430d11b53bfcfa9.jpg

Edited by Danjc
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8 hours ago, Danjc said:

After purchasing my ASI183MM-Pro a few months ago this weekend was the first time I have gone out and had a go at actually capturing something. So a new camera as well as the mount having a new puck, saddle with everything re configured on a losmandy plate oh and it was also the first run out since I had belt modded the HEQ5 it was going to be an interesting night...…..

After getting everything working/sorted on the Sunday night I did manage about 45 min on the pacman.

last night I could just focus on capturing data so decided on the Soul nebula.... 24 300s lights in Ha. I have a slight bit of amp glow on the RHS but I reckon this is because my previously taken dark library was at unity gain (111) but I shot last night at unity gain (120) all the same temp and length, other calibration frames included flats and dark flats.

@Adam J I defiantly made the right choice going mono, Cheers 👍🏻

 

Feedback and criticism welcome.

1464899254_SoulNeb.thumb.jpg.191aa7a1e88b70d92430d11b53bfcfa9.jpg

Firstly you are welcome. Have you used flat frames? I would say that you have got either over correcting flats or the darks at different settings to the lights are causing you issues. You really do need everything at perfectly matched settings. 

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Yes flats used, I going to run off a new batch of darks later as I reckon this may be the problem. 

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User error on my part as having a think I also used previous dark flats which I forgot to retake which wouldn’t have had the Ha filter in the train and obvious slightly different exposure times to my on the night flats. This accompanied with darks & dark flats @ unity gain (111) opposed to on the night unity gain (120) is not going to help........🤦🏻‍♂️

Fortunately my scope is all still setup as it was on the night as I just carefully carried it in the garage so I may just just get away with retaking my dark flats !

The excitement of getting under the stars after a few months away has clearly got the better of me 😁 but hey ho it’s all part of it and I’m just happy I have everything working with a setup I’m now content with.....for now 🤔 hmmm 

 

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2 hours ago, Danjc said:

Yes flats used, I going to run off a new batch of darks later as I reckon this may be the problem. 

If you used flats then you must calibrate them with Dark flats as opposed to bias or they will over correct on CMOS chips, giving this type of effect. Don't use Bias at all with CMOS. 

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1 minute ago, Danjc said:

User error on my part as having a think I also used previous dark flats which I forgot to retake which wouldn’t have had the Ha filter in the train and obvious slightly different exposure times to my on the night flats. This accompanied with darks & dark flats @ unity gain (111) opposed to on the night unity gain (120) is not going to help........🤦🏻‍♂️

Fortunately my scope is all still setup as it was on the night as I just carefully carried it in the garage so I may just just get away with retaking my dark flats !

The excitement of getting under the stars after a few months away has clearly got the better of me 😁 but hey ho it’s all part of it and I’m just happy I have everything working with a setup I’m now content with.....for now 🤔 hmmm 

 

Yes that would cause the problem, retake dark flats and darks with the correct settings and I bet that you will see a big improvement. 

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Dark flats and darks re done and I went with a less is more approach in Startools.

First image is the new version, second the original.

Again feedback more than welcome.1127092127_soulnebula.thumb.jpg.086d1dc44fceab802cb7af8fbbedf17e.jpg

 

2135967688_SoulNeb.thumb.jpg.7a90f2d275b0d4ec4eebf4935a3e064b.jpg

 

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What stacking program did you use? The background seems very uneven. How did you take your flats? 

Can you post the stacked, unstretched file. 

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13 minutes ago, geordie85 said:

What stacking program did you use? The background seems very uneven. How did you take your flats? 

Can you post the stacked, unstretched file. 

I used DSS and I take my flats with a light box app on an ipad.

This should be the file.

 

Autosave001.fit

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17 minutes ago, Danjc said:

I used DSS and I take my flats with a light box app on an ipad.

This should be the file.

 

Autosave001.fit 19.25 MB · 1 download

Thanks

I had a very quick play in Photoshop with a couple curves and levels adjustments. You've got some nice data with very decent stars.

sgl soul.jpg

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10 minutes ago, geordie85 said:

Thanks

I had a very quick play in Photoshop with a couple curves and levels adjustments. You've got some nice data with very decent stars.

sgl soul.jpg

Thanks, that’s a huge difference and I was wondering why my image was not resembling anything like images I have seen online. I guess my processing needs lots of work and practice. 

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14 minutes ago, Danjc said:

Thanks, that’s a huge difference and I was wondering why my image was not resembling anything like images I have seen online. I guess my processing needs lots of work and practice. 

I tried the trial of Startools once and just couldn't even begin to work out how to use it. Have you tried watching any tutorial videos for using Startools? 

I was mainly curious about your image as I have the QHY version of your camera and my results were different. 

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I have watched a few and as we speak doing some research. I was beginning to think maybe Startools isn't for me but then again I also don't know how to use it properly as yet so cant blame the software. I have been mulling over a PS subscription for a while now and I shoud probably give the Pixinsight trial a go.

Out of interest how did your QHY results vary ?

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I have nicked your idea but used Gimp instead of PS which took a couple of minutes, not brilliant by any means but better than my Startools effort I reckon.

 

1687641832_soul.thumb.jpg.03b2a763488ae300198d2d0200fb958f.jpg

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10 minutes ago, Danjc said:

I have nicked your idea but used Gimp instead of PS which took a couple of minutes, not brilliant by any means but better than my Startools effort I reckon.

 

1687641832_soul.thumb.jpg.03b2a763488ae300198d2d0200fb958f.jpg

As they say processing is 50% of the hobby. Its a steep learning curve for sure, but your already making improvements.

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Hi Danjc,

The short version of what's going on; stacking artifacts. Crop them away. They are fairly obvious in the image you posted.

The long version; any StarTools tutorial or video will start by telling you to crop away stacking artefacts. The application itself will warn you about them too if they are detected (as it does with the dataset you posted). When you launch the Wipe module without cropping them away, you are effectively asking Wipe to create and subtract a light pollution model where those stacking artifacts are not being clipped (StarTools will virtually never clip your data unless you explicitly allow it to). In order to satisfy this, Wipe creates a model that locally backs off (e.g. locally subtracts no light pollution at all), causing local light pollution remnants around the edges where the stacking artefacts are located.

Tutorials can be found here, including a "Quick start" tutorial if you're in a hurry.

With regards to your dataset, it is fairly noisy (even when binned), which may make it hard(er) for AutoDev to lock onto the detail. A manual Develop will yield better/easier results in that case.

When/if using Wipe, use the Narrowband preset (as of v 1.5) for this H-alpha data. You may not need to use Wipe if your data is well calibrated and there are no obvious gradients and/or bias signals in your dataset. Your dataset is well calibrated, with nothing too obvious in terms of bias signal.

Autosave001(2).thumb.jpg.04d2d39438cdd42e59d38d882255c33d.jpg

You can get something like the above with a simple workflow like this;

--- Auto Develop

Default values, to see what we got.

We can see stacking artefacts (thin lines around all edges), noise, oversampling.

--- Bin

Converting oversampling into noise reduction.
Parameter [Scale] set to [(scale/noise reduction 50.00%)/(400.00%)/(+2.00 bits)]
Image size is 1374 x 918

--- Crop

Getting rid of stacking artefacts.
Parameter [X1] set to [7 pixels]
Parameter [Y1] set to [8 pixels]
Parameter [X2] set to [1369 pixels (-5)]
Parameter [Y2] set to [911 pixels (-7)]
Image size is 1362 x 903

--- Wipe

Optional, I'd say (see also comments/reasons above).

--- Develop

Final stretch. Choosing a manual Develop here, AutoDev will have trouble locking onto the finer, fainter detail to to overwhelming noise.
Parameter [Digital Development] set to [96.76 %]
Parameter [Dark Anomaly Filter] set to [20.0 pixels]

--- Deconvolution

Usually worth a try. Auto-generate star mask. Only very marginal improvement visible due to signal quality.

Parameter [Radius] set to [1.3 pixels]

--- Wavelet Sharpen

Default parameters. Using same mask that was auto-generated during Decon.

--- Wavelet De-Noise

Default parameters. Parameter [Grain Size] set to [8.0 pixels]

Hope this helps!

 

 

 

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I think the calibration files are out, creating dark central patches in the data which then have to be corrected in post processing. I would certainly stack a set without flats to see what the flats are doing.

Olly

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7 hours ago, jager945 said:

Hi Danjc,

The short version of what's going on; stacking artifacts. Crop them away. They are fairly obvious in the image you posted.

The long version; any StarTools tutorial or video will start by telling you to crop away stacking artefacts. The application itself will warn you about them too if they are detected (as it does with the dataset you posted). When you launch the Wipe module without cropping them away, you are effectively asking Wipe to create and subtract a light pollution model where those stacking artifacts are not being clipped (StarTools will virtually never clip your data unless you explicitly allow it to). In order to satisfy this, Wipe creates a model that locally backs off (e.g. locally subtracts no light pollution at all), causing local light pollution remnants around the edges where the stacking artefacts are located.

Tutorials can be found here, including a "Quick start" tutorial if you're in a hurry.

With regards to your dataset, it is fairly noisy (even when binned), which may make it hard(er) for AutoDev to lock onto the detail. A manual Develop will yield better/easier results in that case.

When/if using Wipe, use the Narrowband preset (as of v 1.5) for this H-alpha data. You may not need to use Wipe if your data is well calibrated and there are no obvious gradients and/or bias signals in your dataset. Your dataset is well calibrated, with nothing too obvious in terms of bias signal.

Autosave001(2).thumb.jpg.04d2d39438cdd42e59d38d882255c33d.jpg

You can get something like the above with a simple workflow like this;

--- Auto Develop

Default values, to see what we got.

We can see stacking artefacts (thin lines around all edges), noise, oversampling.

--- Bin

Converting oversampling into noise reduction.
Parameter [Scale] set to [(scale/noise reduction 50.00%)/(400.00%)/(+2.00 bits)]
Image size is 1374 x 918

--- Crop

Getting rid of stacking artefacts.
Parameter [X1] set to [7 pixels]
Parameter [Y1] set to [8 pixels]
Parameter [X2] set to [1369 pixels (-5)]
Parameter [Y2] set to [911 pixels (-7)]
Image size is 1362 x 903

--- Wipe

Optional, I'd say (see also comments/reasons above).

--- Develop

Final stretch. Choosing a manual Develop here, AutoDev will have trouble locking onto the finer, fainter detail to to overwhelming noise.
Parameter [Digital Development] set to [96.76 %]
Parameter [Dark Anomaly Filter] set to [20.0 pixels]

--- Deconvolution

Usually worth a try. Auto-generate star mask. Only very marginal improvement visible due to signal quality.

Parameter [Radius] set to [1.3 pixels]

--- Wavelet Sharpen

Default parameters. Using same mask that was auto-generated during Decon.

--- Wavelet De-Noise

Default parameters. Parameter [Grain Size] set to [8.0 pixels]

Hope this helps!

 

 

 

A big help thanks, I’m sure I’m just scratching the surface with startools and will persevere.  

3 hours ago, ollypenrice said:

I think the calibration files are out, creating dark central patches in the data which then have to be corrected in post processing. I would certainly stack a set without flats to see what the flats are doing.

Olly

I’m sure @david_taurus83 mentioned the same just not had chance yet but will give that a bash later, Cheers. 

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Posted (edited)

This image is without any flats.

 

 

Soul Neb no flats.jpg

Edited by Danjc

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looks better without flats. So its miss-calibrated flats.

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I don’t think the technique and old iPad I’m using help thinking about it. I noticed when taking the flats that when I rested the iPad on top of the ED80’s dew shield that the iPad had pressure spots in an around the places where the iPad touched the dew shield. As well as that I probably should place a piece of thin white A4 paper in there to as the screens are of a glossy/reflective nature. 

I used the flats aid in APT so just went with the auto generated flats plan it made for me. It’s obviously user error on my part and I’m finding the transition from DSLR to my asi183 throwing up a few unexpected differences but I have also learned a load from just my first image with help from you all so thanks for that 👍🏻

Any pointers on how I can improve would be appreciated. 

 

Dan. 

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Just now, david_taurus83 said:

Can you post up a single flat and the master flat generated by DSS?

No problem, I will pop them up when I’m back at the laptop. 

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My main gripe with APT is the histogram will only give you a minimum and maximum ADU value. When shooting flats we look for the mean value so they cant be done manually in APT. You kind of at the mercy of the Flats Aid.

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