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M94 Croc's Eye Galaxy - LRGB stacks added to first post if anyone wants to try.


tooth_dr

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Here is my attempt at M94, all data collected on the 14th April 2020.

 

I have a dual rig consisting of the following:

Skywatcher 250PX 1200mm F4.7 with a QHY9 mono CCD, imaging at 0.93"/px

Skywatcher ED80 520mm F6.3 with an ATIK 383L+ mono CCD, imaging at 2.13"/px

 

I had the idea of collecting LUM with the 10" newt, and using the smaller 80mm refractor for RBG.

Data as follows -

Luminance: 45 x 300s

Red: 15 x 600s

Green: 9 x 600s

Blue: 8 x 600s

 

Data collected in SGPro, processed in APP and PS.

 

I would appreciate any feedback.  I couldn't get the colour as I wanted it, so it ended up a bit on the red side.  LRGB is still a dark art to me.  I have an issue with elongated stars pre-meridian in the 10" scope, which arent there post-flip.  I might post a thread about this and try to get it sorted.  There are also a few nasty reflections in different images I've taken, so I'll need to get that sorted out too.   You can see one along the bottom of this image.  My ED80 subs drift throughout the night - if I flick from the first to last image there is relative movement.  I use an OAG on the 10" so flexure is obviously playing a role here - but it doesnt seem to affect the less demanding imaging scale of the ED80 so I'm not too bothered.  I just really need to sort the pre-meridian stars in the 10".  

 

Thanks for looking

Adam.

 

M94-LRGB.thumb.jpg.31870d4c7a15133bf785fc34c75823b9.jpg

 

 

 

 

St-avg-9000.0s-LNMWC_1_3.0_none-x_1.0_LZ3-NS-full-qua-add-sc_BWMV_nor-AAD-RE-noMBB-Red.fits St-avg-5400.0s-LNMWC_1_3.0_none-x_1.0_LZ3-NS-full-qua-add-sc_BWMV_nor-AAD-RE-noMBB-Green.fits St-avg-4800.0s-LNMWC_1_3.0_none-x_1.0_LZ3-NS-full-qua-add-sc_BWMV_nor-AAD-RE-noMBB-Blue.fits St-avg-13500.0s-LNMWC_1_3.0_none-x_1.0_LZ3-NS-full-qua-add-sc_BWMV_nor-AAD-RE-noMBB-Luminance.fits

Edited by tooth_dr
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That is a tremendous image Adam!

Galaxies are my favourite objects indeed,and close up shots like these never fail to amaze me!Just looking at this image makes me wondering about all the  secrets this galaxy holds.

I also had this idea of combining frames from diffrent setups,but i never actually was sure if it would work.Did dss itself crop the frames and stacked them or you had diffrent stacking process because of the diffrence in focal lengths.

-Clear skies,David

 

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11 minutes ago, TheDadure said:

That is a tremendous image Adam!

Galaxies are my favourite objects indeed,and close up shots like these never fail to amaze me!Just looking at this image makes me wondering about all the  secrets this galaxy holds.

I also had this idea of combining frames from diffrent setups,but i never actually was sure if it would work.Did dss itself crop the frames and stacked them or you had diffrent stacking process because of the diffrence in focal lengths.

-Clear skies,David

 

Thanks David

I am really enjoying have a longer focal length to image with, and agree galaxies are incredible in every way!

When it came to processing, I used software called Astro Pixel Processor.  It will register different sized and scaled images to a reference image.  In this case I wanted to keep the scale of the bigger scope.  I loaded all my subs into the program, along with calibration data.  I chose to register my RGB subs (taken with the ED) to the best LUM sub.  So that LUM sub became the 'reference image' and so every other sub from both scopes was aligned to the stars in it.  It took a few runs of the stacking software, with a few adjustments of the settings, and in the end omitting darks from the QHY9 as these added black speckles everywhere, I was able to register the data, and produce four aligned stacks: L R G B.  It then all went downhill when I imported it to PS :D

 

HTH.

Adam

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5 minutes ago, tooth_dr said:

Thanks David

I am really enjoying have a longer focal length to image with, and agree galaxies are incredible in every way!

When it came to processing, I used software called Astro Pixel Processor.  It will register different sized and scaled images to a reference image.  In this case I wanted to keep the scale of the bigger scope.  I loaded all my subs into the program, along with calibration data.  I chose to register my RGB subs (taken with the ED) to the best LUM sub.  So that LUM sub became the 'reference image' and so every other sub from both scopes was aligned to the stars in it.  It took a few runs of the stacking software, with a few adjustments of the settings, and in the end omitting darks from the QHY9 as these added black speckles everywhere, I was able to register the data, and produce four aligned stacks: L R G B.  It then all went downhill when I imported it to PS :D

 

HTH.

Adam

Thanks for explaining it to me,i cannot believe i haven't heard about that program until now,guess i'll have to try this technique when the first chance apears

 

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You have the details in the spiral arms pretty good, and the processing is not overdone, I like that. Maybe you could tease out some detail closer to the core if you process another stack, aiming just at the core, and then blend the two versions together. I also find the colour a little towards magenta, maybe there are still some hidden colour data that could contribute. But averall a nice image of a not-so-easy target.

Ragnar

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I reworked my RGB data using some very good advice from Xiga on here.

Unfortunately once it came to processing and adding it to the LUM, I hadnt a guide to follow so it went downhill rapidly.  However I have managed to shift away from all my RGB images looking yellow.

This is what I now have, any advice on working with the Lum ie link to a good PS guide ,that would be appreciated.

 

Thanks again

Adam.

 

M94-LRGB-2.thumb.jpg.cbb1ca2d8b70a63f361ec6efcbc30502.jpg

 

 

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14 hours ago, tooth_dr said:

It is very blue now 😂

Adam, i had a look at the data and i think i know where things went awry. When you calibrate the stars in APP, the default 'Red-Blue' setting doesn't work for this image. It produces way more Blue stars than Red. So you just need to move the slider over towards Red, then you will see the graph change such that the upper-right quadrant of the bottom graph becomes much more densely populated than the lower-left quadrant. 

I had a quick go at your data. I used a setting of 0.25 for the Red-Blue slider to calibrate the stars. Then into PS for the rest. I only had to use a small amount of NR on the Lum (about 40% of Noel's Space Noise Reduction). Really enjoyed processing this, so thanks for sharing. 

ps - I didn't focus on the stars too much. With this dual-rig setup, i think you are going to find that the stars will be the hardest part to get right, as they are completely different sizes due to the large difference in FL. 

1031025159_AdamsM94v1.thumb.jpg.c39498bb5f4a1d8d11433caca6bf2719.jpg

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1 hour ago, Xiga said:

Adam, i had a look at the data and i think i know where things went awry. When you calibrate the stars in APP, the default 'Red-Blue' setting doesn't work for this image. It produces way more Blue stars than Red. So you just need to move the slider over towards Red, then you will see the graph change such that the upper-right quadrant of the bottom graph becomes much more densely populated than the lower-left quadrant. 

I had a quick go at your data. I used a setting of 0.25 for the Red-Blue slider to calibrate the stars. Then into PS for the rest. I only had to use a small amount of NR on the Lum (about 40% of Noel's Space Noise Reduction). Really enjoyed processing this, so thanks for sharing. 

ps - I didn't focus on the stars too much. With this dual-rig setup, i think you are going to find that the stars will be the hardest part to get right, as they are completely different sizes due to the large difference in FL. 

1031025159_AdamsM94v1.thumb.jpg.c39498bb5f4a1d8d11433caca6bf2719.jpg

Thanks Ciarán. I’ll try this again. That’s some difference. 

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Very nice image. I'm surprised that your camera didn't pick up the Ha signal near the core. It is very strong in my data.

On 23/04/2020 at 22:53, tooth_dr said:

I have an issue with elongated stars pre-meridian in the 10" scope, which arent there post-flip

My guess is that this is a balance issue. The scope may be West heavy pre-flip and East heavy post-flip, ie you have to adjust the counter weights slightly outward.

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1 hour ago, wimvb said:

Very nice image. I'm surprised that your camera didn't pick up the Ha signal near the core. It is very strong in my data.

My guess is that this is a balance issue. The scope may be West heavy pre-flip and East heavy post-flip, ie you have to adjust the counter weights slightly outward.

Thanks Wim.  It could be a balance issue, I hadnt thought of that.  I have it quite well balanced, with no preference to east or west.  Would there be a way of checking the orientation of the elongation to see if it was drift due to balance/tracking, rather than a focuser issue?

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If the elongation is along RA, it's tracking/balance. With most mounts (generally not the high end models, and maybe not belt driven either) having the scope slightly East heavy, keeps the gear engaged and improves tracking. But East heavy before a flip becomes West heavy after, and vice versa.

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59 minutes ago, wimvb said:

 

If the elongation is along RA, it's tracking/balance.

 

Thanks again Wim.  I’ll have a look at doing that! Not sure how to chart the RA/DEC lines on the images that I see others doing.

Edited by tooth_dr
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4 minutes ago, wimvb said:

But unfortunately, not a quick fix. Since the elongated stars are only before the flip, why don't you just stack those subs, to isolate the problem? Or post a single sub.

I’ll post a single sub shortly cheers!  

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@wimvb

Here are a selection of single subs taken pre-meridian flip, any feedback would be appreciated.

I have checked collimation at the different positions.  I used my Tak collimating eyepiece, and the collimation doesnt change no matter where the scope is pointed.  The focuser is 180 degrees to relative to the ground which got me thinking that was the problem.  I have a Mesu e200, so balancing is critical, and with a dual rig and two very different scopes it could be an issue, but I'm would say I was confident that it's accurately balanced in all three axis.

 

 

Ha_M106FriendsHa_600sec_.jpg

Lum_m64_300sec_.jpg

Lum_m94_300sec_.jpg

Lum_ngc3344_120sec_.jpg

Lum_ngc4565_300sec_.jpg

Lum_m101_300sec_.jpg

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I think those satellite trails are an indication. They wiggle somewhat in the same direction as your star elongation, because the wiggle has a saw tooth shape. It seems to me that you have a vibration. A guide log may tell you more. Also, check for satellite trails in any post-flip subs. Do they show that same wiggle?

Edited by wimvb
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Btw, I'm working on your image. I'm having a bit trouble with the colour, but the L is a pleasure to work with. You've got great detail. Here's what i got so far.

tootdr_m94_L.thumb.jpg.b131eca3480ef0ce730e0cf8ec305830.jpg

(click on the image to view full size)

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I can post logs guys, all PHD2 stuff is stored on the observatory PC, and I'm almost in bed, I'll post logs tomorrow that relate to the images.

I havent noticed satellites trails like that before I started using the 10" scope (but I've also changed mounts too so thats two variables changed.

Are they the same pre and post flip - in short yes it appears so!  I found this image of M94, and it's post-flip, and the satellite is wobbly.

 

 

 

 

Lum_m94_300sec_1x1_-20C_250PX_0052-St.jpg

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