Imaging with the Samyang 135mm f2

[AstroNebulee]

21 hours ago, beamer3.6m said:

The Plaides from Bortle 4 skies in Yorkshire.

30 x 180s lights

30 x flats

60 x bias

Unmodded 1100d

AZ-GTI (EQ and tracked)

Samyang 135

Stacked in Siril and processed in Lightroom.

Not brilliant but getting better

Nice image. Try using Starnett ++2 (free) on your siril stretched image to remove the stars, then you can work on the starless image a bit and then do a small stretch on your unstretched stacked image to bring out the stars a little and gently blend back in with your starless image. Not sure how to do this in light room but in photoshop just paste your starless image on top of the slightly stretched stacked image and choose screen in the blending modes and move the opacity slider to taste. 

Lee 

[beamer3.6m]

Can you clarify what you mean by stretched and unstretched images as I'm confused.

I stack in siril... do some simple processing and deal with the histogram then save it... do I remove the stars then in starnett++??

Then process the removed stars image in photoshop...

I'm confused

Edited October 4, 2022 by beamer3.6m

[powerlord]

deal with the historgram - is the stretching bit. i.e. stretching the histogram.

yeh, usually you'd stack, stretch aka deal with histogram a bit, and save as a 16 bit tiff file.

you can then use startnet2++ (there is a windows gui now), and remove stars.

you can get the stars back later in PS by subtracting (layer blend mode) the starless image from the one with stars in it.

you can then edit your starless image wherever and should find it much easier to see any nebulosity and tweak details out of it.

you might wanna have a look at my quick tutorial I did last week - it's for APP and affinity, but it will show the stars process, etc.  -its pretty rough but you'll get the idea

 

[beamer3.6m]

Thank you... I will check out your vid

 

[beamer3.6m]

I had a play and managed to produce a 'more natural' look I think...

[AstroNebulee]

5 hours ago, beamer3.6m said:

I had a play and managed to produce a 'more natural' look I think...

Definitely much better this time, you have made great progress 👍

[Phillyo]

Another image with the SY135. 7 and a half hours of data on this with the Risingcam IMX571 through the Antlia 5nm ALP-T filter. I've remove the stars to show the structure of the nebula a bit more but a fairly nasty gradient has appeared so I need to take care of that. 

Phil

[powerlord]

you did well to get the ellusive squid in 7.5 hours. very nice. 

a scattering of stars does wonders to hide noise and gradients. I use affinity photo and James Ritsons star eater macro at 1px usually

👍

[Phillyo]

1 hour ago, powerlord said:

you did well to get the ellusive squid in 7.5 hours. very nice. 

a scattering of stars does wonders to hide noise and gradients. I use affinity photo and James Ritsons star eater macro at 1px usually

👍

With stars  I wanted to show more details in the nebula without the stars, but you're right it does hide it lol

[janewastro]

Hi all,

I'm looking for options to mount my Samyang 135mm and ASI533MC Pro to a dovetail. I've heard the ring for the William Optics Red Cat fits well on this lens. Are these the correct rings and do they support the camera and lens well on the dovetail? Are any additional rings needed to support the weight or will just the one suffice? I'm considering getting the ZWO Camera Ring as well to support the weight better, but this will have to wait until a later date. 

 

Edited October 8, 2022 by janewastro

[Phillyo]

Just curious, people that are using this lens with an APS-C size sensor (ASI2600, QHY268, Risingcam IMX571 etc), how bad is the vignetting you're getting from your light frames?

[powerlord]

I don't get much. I don't even get much with my FF 6D on it.

 

@janewastro you might want  to see if you have a friend that can 3d print something for you especially if you plan to use an EAF with it. I use modified versions of this:

https://www.thingiverse.com/thing:4667525

I have 4: One on my SY135, a canon 300mm, a redcat and a spare for mounting pretty much any lens.

 

stu

[Phillyo]

I'm wondering if I'm getting dew forming on the sensor which is causing the vignetting issue. It's quite severe, even with flats it's still quite visible. Here's a stretched stacked image from last night (no calibration frames). This was during a full moon too. 

[Phillyo]

And this is no moon, but also maybe no dew? Again, no calibration frames just stacked data. Very very different!!

[powerlord]

hmm doesn't look like dew - stars are sharp. what's weirder is the difference and you saying it doesn't calibrate out though. could it be reflective light and background light ? I take it you use the lens hood ? maybe try a longer cylinder extending a bit out of cardboard ?

But I never image without dew heaters tbh - summer or winter my scopes and finders all have em.

[Phillyo]

1 minute ago, powerlord said:

hmm doesn't look like dew - stars are sharp. what's weirder is the difference and you saying it doesn't calibrate out though. could it be reflective light and background light ? I take it you use the lens hood ? maybe try a longer cylinder extending a bit out of cardboard ?

But I never image without dew heaters tbh - summer or winter my scopes and finders all have em.

Yeah I have dew heaters on the scope and finder, plus the lens has the hood on it too. It's really strange!

[janewastro]

56 minutes ago, powerlord said:

I don't get much. I don't even get much with my FF 6D on it.

 

@janewastro you might want  to see if you have a friend that can 3d print something for you especially if you plan to use an EAF with it. I use modified versions of this:

https://www.thingiverse.com/thing:4667525

I have 4: One on my SY135, a canon 300mm, a redcat and a spare for mounting pretty much any lens.

 

stu

Thanks for this! I am however looking for non-3D printed solutions as I have bought two previous 3D printed rings for this and both have failed quickly. I do see many people using them, but I don't have confidence in them anymore because of this. 

[Elp]

Best to use the rings designed for the application:

https://www.firstlightoptics.com/zwo-accessories/zwo-holder-ring-for-asi-cooled-cameras-78mm-diameters.html

The holes in the base are very odd though as they don't align with what I've attached it to very well, you'll need to source like I did some cap head screws, washers and nuts to attach to a dovetail bar. Mine is mounted directly onto a cheese plate so I can also put on some longer screws into the cheese plate acting as physical stops securing the camera/lens from moving forward or backward.

Edited October 9, 2022 by Elp

[Elp]

Another option is to get a ring holding the camera lens adaptor/filter drawer which I do with another lens/camera combo. It's slightly better this way as it holds nearer the centre of gravity of the assembly.

[janewastro]

42 minutes ago, Elp said:

Best to use the rings designed for the application:

https://www.firstlightoptics.com/zwo-accessories/zwo-holder-ring-for-asi-cooled-cameras-78mm-diameters.html

The holes in the base are very odd though as they don't align with what I've attached it to very well, you'll need to source like I did some cap head screws, washers and nuts to attach to a dovetail bar. Mine is mounted directly onto a cheese plate so I can also put on some longer screws into the cheese plate acting as physical stops securing the camera/lens from moving forward or backward.

Thank you! I was intending on getting one of these at some point to use with wider lenses so I might just go with this option. I was just unsure if it would result in some sort of stress/flexing between the camera and lens considering the ring would be away from the centre of gravity by a bit. Perhaps a combo between this and the WO ring could work to balance it out. 

[Elp]

As long as it's mounted to the dovetail or base plate securely it's fine using the ring just around the astro camera, but make doubly sure it's clamped tight. The Samyang 135 is a heavy lens for what it is, none of my other lenses are anywhere close to it's weight, not even their own 50mm or 14mm (which also is a large piece of glass).

[Spedz]

Took this over the weekend of the 7th and 8th during the full moon.  Wanted to test out how my Skytech triband filter would perform under those conditions.  Think I went a bit to aggressive on the star reduction in the processing, photoshop bit is still a massive struggle for me 😅

Best 80% of 7h40mins of lights totalling 6h27mins.  

Asto modded Canon 700D, Star Adventurer, Skytech Triband filter, Samyang 135mm.

Edited October 11, 2022 by Spedz

[AcapulcoRolf]

Saw first light with the new setup this past couple of weeks. Loving this lens

Just now waiting on the Astro Essentials Samyang Lens to M48 Adapter from FLO , but for now using the somewhat "wobbly" ZWO EOS Lens Adapter 

NGC 7822 The Cosmic Question Mark
Samyang 135mm @f/2.6
ZWO ASI294MM Pro
Celestron AVX
SII 68x180s 125/30
Ha 80x180s 125/30
OIII 60x180s 125/30

 

NGC7822 taken 14th/15th and 15th/16th October 2022 from my back garden

[Adreneline]

28 minutes ago, AcapulcoRolf said:

Saw first light with the new setup this past couple of weeks. Loving this lens

You should be delighted with that image. I love the subdued colours and the framing with the Little Rosette is perfect - you've managed to achieve some real depth in the centre of NGC7822.

I took a look close up and be careful with the noise reduction - it is introducing some unwanted artefacts.

What method did you use to reduce noise? This sort of thing call also arise with star removal.

I know you/I shouldn't pixel peep so hope you don't mind the comment.

Adrian

[AcapulcoRolf]

4 minutes ago, Adreneline said:

You should be delighted with that image. I love the subdued colours and the framing with the Little Rosette is perfect - you've managed to achieve some real depth in the centre of NGC7822.

I took a look close up and be careful with the noise reduction - it is introducing some unwanted artefacts.

What method did you use to reduce noise? This sort of thing call also arise with star removal.

I know you/I shouldn't pixel peep so hope you don't mind the comment.

Adrian

 

Hi Adrian

My image posted here has no doubt been munged by my iPad after I tweaked brightness/saturation/vibrance/contrast before uploading here so will no doubt suffer from compression on close inspection/pixel peep

As the image came out of Pixinsight untouched by iPad, noise reduction used was MLT and also SCNR

Original jpg export of xisf image direct from Pixinsight attached here as a reference