Adreneline

Sadly that is not the Great Pyramid of Giza - it's the local Methodist Chapel  

Looking NNE over the Lincolnshire Wolds.

Adrian

Looking NNE over the Lincolnshire Wolds on 21st June 2022. 

Canon 6D + Samyang 85mm manual lens at f2 , 2 second exposure.

Adrian

1 hour ago, Paul Holdsworth said:

I would guess it's the new noise exterminator script that I've not used correctly though I have to say I'm impressed with its noise reduction capabilities.......of course it could be star reduction that's caused it.

Hello Paul.

I think it unlikely that the new NoiseX has done this - I only used it through the trial period but didn't notice anything odd going on.

For what it is worth I tend to perform whatever initial noise reduction is required (my preference is nearly always MLT with an L mask - four layers) and then make a clone of the noise reduced image. I strip the stars from the original and process that to the extent I think is right for the target. With the clone I use EZ Soft Stretch on the image followed by MMT to reduce the stars a tad and then strip the stars out using Starnet2 to combine back with the (now starless but fully processed) original. When combining back I usually just do a straight addition in PixelMath although I was recently given this formula ~(~starless*~stars) which produces slightly 'dimmer' stars compared with a straight addition; modifying to this ~(~starless*~(1.2*stars)) will up the star brightness a tad.

I have found putting stars back is a real challenge - it is loads more difficult that just whipping them out with StarXterminator or Starnet2 that is for sure!

I hope this helps/is of interest.

Adrian

Hi Paul,

This is a target I keep meaning to have a go at - great framing and colours, and no evidence of halos but there is something a little tricky going on with the stars.

You don't make any mention of the processing processes so not sure what might have introduced these sort of artefacts.

I have seen Topaz DeNoise do strange things like this but not sure if that applies here.

HTH

Adrian

For those who might be interested this is the APP screen upon completion of the mosaic from the four master frames:

A slight rotation and a small crop to arrive at the image shown above.

I used the ASIair SkyAtlas to plan the image - nothing technical - just lined the panes up by eye

Adrian

2 hours ago, juno16 said:

Beautiful mosaic Adrian!

This is a very rich area and I am very fond of Ha (monochrome) images. I guess that it somewhat reminds me of my old b&w film processing days.

The starless is nice, but the stars in your first image are very tastefully done and to me add quite a bit to the overall view. 

Very nice work!

Thanks Jim. Considering it was not astro-dark it worked pretty well really - even without astro-dark the skies here are pretty dark fortunately. I tried a new approach to adding stars back (thanks to @Rodd) and it has worked really well. AstroPixelProcessor makes assembling mosaics so easy - some experimentation was required to home in on the optimum values but in the end the star field looked really good across the whole image.

I cannot begin to imagine doing the above with a film camera.

1 hour ago, geeklee said:

That's a cracker Adrian.  Excellent processing with the weak and strong nebulosity flowing together so well alongside the excellent star control.  The starless one is so good - for a change enjoyed viewing the image in its entirety as big as you can - brilliant depth throughout.

Thank you Lee. It's turned out better than I expected. It needed a few runs in APP to get the stars sorted at the overlaps but in the end it has worked pretty well. Also tried a new approach to assembling the finished image from the component parts (see PM).

I think it might be a few weeks before I can add anymore Ha or OIII - the OIII might spoil it  so might be best left as is.

Adrian

Taken over two nights of none-astro-darkness this is a four pane mosaic of the Sadr region taken with the Samyang 135mm + ASI183MM; in total it comprises 60 x 300s subs.

Each pane was processed in APP and then the mosaic compiled from the separate masters, again using APP.

Processed in PI.

I think the starless version helps to see the structure more clearly.

The trouble is knowing where to stop! This project might grow to encompass more of the surrounding nebula.

Thanks for looking.

Adrian

8 hours ago, Rodd said:

~(~Starless*~starsonly)

This works rather well - just tried it on one of my images - thanks for the heads-up Rodd.

Glad you've made your way to the starless universe! Enjoy!

Adrian

9 minutes ago, Rodd said:

I will definitely see if I can find the starless tools.  I don';t really want to buy it though.  How much is it?  I will look for it in the process console.  I know it is not in my tools--you know you "list all" and then all the tools appear and you choose one--curves, historgram, TGV  etc.  Its not in that list.

I purchased StarXterminator just before the new StarNet2 came out - wouldn't you know it!! Both are very effective but again both can give slightly different results - it all depends on the image.

Starnet and StarNet2 install as part of the PI installation - there is no additional cost.

(As an aside StarXterminator has now been joined by NoiseXterminator which seems to be generating a lot of interest on the PI front.)

13 minutes ago, Rodd said:

All the things you say about the image were very carefully striven for, so it pleases me to see someone has noticed.

There is so much subjectivity when looking at images - your own and images produced by others. We should all strive to get the best result from the data we have and in my opinion your image is up there with the best. Can it be improved? We should always like to think so  - otherwise what's the point?

Adrian

19 hours ago, Rodd said:

Very disappointed.  I do not understand it.

To be honest Rodd I don't really understand why you are disappointed. To my eyes this is an excellent image of a very difficult target. The main subject is well defined with a very pleasing amount of colour - not overstated but sufficient to reveal an extraordinary level of detail. As you pointed out to me on my recent M13 image backgrounds are tricky things and all the more so when the background itself contains nebulosity which again to my eyes looks controlled and well balanced withe star of the show - NGC6888.

As stated above I now use Starnet/StarXterminator as a matter of course in PI for processing nebula images; doing so provides a much greater degree of control over processing of the stars and the nebula. I know others say putting the stars back is a simple matter but that has not always been my experience if you want to avoid them looking 'stuck on'. Personally I never just put the processed 'star only' image back with PixelMath. Experimentation is best to find a method that works best for the image you are working on - in my opinion there is no single solution. I tend to use a duplicate which I process complete, taking lots of care not to overprocess and then use star reduction on that image and maybe MMT. I then remove the stars and blend those back using PixelMath and a 'lighten' formula or sometimes a 'screen' formula.

Adrian

It is an interesting question but even if it is recorded by the sensor your eyes won't see it anyway unless we map the UV/IR to a colour range our eyes can see. I know my eyes can't see in the infrared range nor the ultra violet - maybe some folks are more fortunate - or unfortunate - depending on how you look at it! I don't believe eyes are like ears - my son can clearly hear bats - I just hear tinnitus  

This is the third and final version of my experimenting with L+osc data on M13.

The first version was 3hrs of Lum from the ASI1600; the second version was Lum + 30 mins of osc from a Canon M6 MkII; this is the Lum + 30 mins osc from a Canon 6D.

The 6D has offered more colour content but with less definition; combined with the Lum data however I think overall the 6D has delivered a more pleasing end result.

Processed in PI using the GHS script to try to preserve star size and maximise colour; I've not used any star reduction processes/scripts.

Thanks for looking.

As always C&C are welcome.

Adrian

20 minutes ago, Astro Noodles said:

Is the correct procedure to process the images first and then stick them together, or do you stick them together and then process the resulting mosaic image?

I have no experience of doing this in ImageJ but I have done a lot of mosaics in AstroPixelProcessor.

I've tried both approaches in APP and have found the best results are obtained by stacking, registering and integrating the individual panes and performing any light pollution correction and then combining the individual panes into the finished mosaic. APP does an amazing job of not only registering the individual panes (even from different camera/optics combinations) but also blending the background of the individual panes seemlessly.

P.S. This is the approach recommended in the Sara Wager tutorials using APP.

13 minutes ago, woldsman said:

Thanks! Do you use a guide camera? Just wondering where it would go. Having the EAF mounted below on the dovetail would free up a perch for a guide scope on top. 

10 minutes ago, Adreneline said:

No. Fortunately I don’t need to guide with the CEM25-EC. Mounting the EAF below the Samyang would allow a small guide-scope to piggyback above I suppose. 

2 minutes ago, woldsman said:

Thanks! Do you use a guide camera? Just wondering where it would go. Having the EAF mounted below on the dovetail would free up a perch for a guide scope on top. 

No. Fortunately I don’t need to guide with the CEM25-EC. Mounting the EAF below the Samyang would allow a small guide-scope to piggyback above I suppose. 

Rarely imaged Sh2-150 and Sh2-145 in Cepheus.

Really happy with the corner star shapes. 

15 minutes ago, woldsman said:

Hi, Things have moved on for me. I’ve a new scope and am happy with its manual focus. So am thinking of redeploying the EAF to the Samyang 135 widefield rig. Could I ask where you sourced the belt drive and the red attachment that you put on the Samyang focus ring? 

The EAF (or similar) is essential for the Samyang 135. I bought my belts and HTD gears from Motionco.co.uk . The red ring was 3D printed from an existing design intended for a RedCat 51. Prior to the red gear ring I used a section from a second belt which I attached to the lens using a double sided tape purchased off Amazon - that arrangement worked really well considering it was so simple. You don’t need to cover the whole circumference - just enough for the drive belt to engage to ensure good registration. I tried using the drive belt alone on the focuser ring but unless you employ excessive tension the drive belt will slip or ‘process’ and you won’t get repeatability in absolute focus position from the EAF.

HTH

Adrian

2 hours ago, Tom33 said:

would it be better to upgrade the focuser as well as fitting me EAF.

I use an EAF on all three of my OTAs (RedCat, 6"RC and Samyang 135mm) - they are perfect for my needs allowing fine focus control and repeatability.

I used to own an ED80 and used it with a SW dc motor focus unit, initially with the stock focuser. The problem was the drawer tube kept slipping so I could not go back to a focus position with any degree of repeatability. In the end I swapped the stock focus unit for a Baader Diamond SteelTrack (BDS) and never looked back. There are times I wish I'd never sold the ED80 - with hindsight it was a great scope.

Good luck.

P.S. The EAF comes with an 'L' shaped bracket and a variety of couplers and will definitely fit on a BDS but it does leave the EAF sticking way out at the side of the OTA which made it really difficult to balance when used on my CEM25 mount.

I have the BDS+EAF on my 6" RC but chose not to use the direct shaft coupler - I prefer a piggy-back belt drive arrangement.

The BDS focus unit has a HTD compatible belt pulley built in! Very handy

HTH

43 minutes ago, Rodd said:

The background looks great!  And the stars look good too. The image looks very real, like it would through a big dob.

Thank you Rodd. I've always steered away from GCs in the past because in my opinion they are the hardest things to image and image well. My previous attempts have been dismal for a whole variety of reasons.

I'm hooked now! I think my L data is all good, it's the osc/RGB data that needs more time. I might have a go with the 6D in the coming nights just to see how it performs alongside the M6 - the big pixels should help and as the detail is in the L the lower resolution should not be limiting.

Thank you again for your feedback and comments.

Adrian

On 15/05/2022 at 13:17, Rodd said:

I do see some color mottling in the background.

Hi Rodd.

I've taken on board your comments about background and had another go at the image. As ever I've introduced another variable, namely the addition of my 7 x 120s iso1600 subs.

I hope you think the background has improved albeit at the expense of the stars - I probably should have left the 120s subs out.

I need to keep in mind this was never really intended to be an M13 imaging session - M13 was just convenient as part of the process of collimating my RC - a bonus so to speak.

It has certainly encouraged me to have a proper go at M13 once we get astro-darkness back in late July/early August.

Once again thank you for taking the time to give me your advice and feedback.

Adrian

1 hour ago, FranckiM06 said:

Wow, it is fantastic image and very sharp. Also your process is very good. Congratulations about your wonderful image. I have done the same with my small diameter  : 

https://www.astrobin.com/h11pew/?active=2021

Thank you Francki for the kind comments. I've only been at this AP game for six years and I have always thought that imaging GCs is the hardest thing of all - which in part is why it's taken me six years to post one - my previous efforts have been dismal in all respects  

Hopefully I can get some more colour when the dark nights return and improve the signal to noise issue. I might also try my 6D instead of the M6 as the larger pixels would gather more signal and be better suited to the RC.

Adrian

P.S. Your M13 is definitely better than my effort - your background is much cleaner (no mottling) and there is every bit as much definition and colour in the core - if not more! Excellent job.

Hello Steve,

I've been playing with my M13 osc data, this time incorporating the 7 x 120s subs at iso800 - dithered - with the 15 x 60s at iso800. Lack of astro dark, a Moon and clouds conspired to limit what I got but all I was wanting to do was try out the Canon M6 with the RC and see if the colour it collected was any good - if not next time I'll try my 6D instead.

Anyway! I did a comparison of NoiseX, MLT-NR and EZ-NR and this is what I found on the same stack of data (prior to NR I used BackgroundNeutralization and SCNR).

You need to accept that the total amount of integration time here is only 29 minutes so you can't expect too much from the integration - it is noisy! This was all about trying hardware and checking collimation and not about imaging M13 - M13 was just bright and conveniently placed.

I only tried the one setting of NoiseX (0.7). Personally I would not be too quick to dismiss it. As with all of these NR processes and plugins (irrespective of the parent application) the results will differ from stack to stack, target to target, and as with all of these things there is no magic bullet or setting that works on every image.

I get very frustrated by this smash and grab approach to imaging and processing these days; too many images show a marked lack of care and attention to detail - just get it out there. Everyone seems driven by a desire to get an image of a target with minimal integration time using the new low noise CMOS camera, throw the lot into their preferred application and with the press of as few buttons as possible get an amazing image. With AP it is the total challenge that matters and makes the hobby so enjoyable. Too many are too quick to dismiss new things - and I am old and entitled to the view  

Draw your own conclusions from the above.

Adrian

1 hour ago, teoria_del_big_bang said:

That's just brilliant, and I do think it looks better not glaring in blue.

I can't wait to get my RC6 up and running, plenty of time before we get astro darkness back.

Steve

Thank you Steve. You see too many images where colour seems to be everything - the more the better - but I think it often hides detail and structure and less is often more in the finished image.

The RC6 can be a challenge and it can be tempting to invest in all manner of expensive collimation devices - I have been tempted! In the end I just used a cheap laser eyepiece type thing to get it in the right ball park and then cast caution to stars and set about the secondary outside pointing at not too densely populated star field. I have to say I have taken it as a given that the primary was 'true' and upgraded the focuser to minimise droop. I've also used spacers to try to ensure there is minimal focuser extension. I think it has paid off. Non-astro dark is a perfect time to get these things sorted. Good luck!

Adrian

19 minutes ago, newbie alert said:

collimation looks spot on

Thank you.

This is a rather poor screenshot of the defocused stars - the rings are as close to concentric as I can get - I fear if I try any harder to get it perfect I will mess it up!

Adrian