Imaging with the Samyang 135mm f2

[vlaiv]

48 minutes ago, barbulo said:

Is it a good idea to 3D print them?

I've printed aperture mask for Samyang lens (although 85mm version) that uses filter thread.

If you can print fine pitch (like 0.75) - then I see why not. I simply use 0.12mm layer height and design a bit more tolerance into the part and it works.

Sometimes it needs to be screwed in all the way few times to "clean up" the thread, but after that it's rather smooth.

[barbulo]

7 minutes ago, vlaiv said:

I've printed aperture mask for Samyang lens (although 85mm version) that uses filter thread.

Thank you very much @vlaiv. Did you print the thread? How did you designed it?

[powerlord]

I use solidworks which has threads as standard. I'd imagine others have similar ? As vlaiv says, print at 0.1 slow with PLA and should come out fine - be careful first few times you screw it into something to ensure it doesn't cross thread, and the aluminium will cut the 3d thread and make a clean thread which is easier to thread next time.

 

[vlaiv]

1 minute ago, barbulo said:

Thank you very much @vlaiv. Did you print the thread? How did you designed it?

I design threads in FreeCad by doing following:

Create sketch that is in plane perpendicular to threads. Sketch should contain metric profile - it just depends if you want to do internal or external thread and if you want to apply additive or subtractive operation.

Both can be designed with both - but it will impact your profile.

Say you want to do internal thread with subtractive method - then you will use nut thread profile - which means tooth top will be 1/8th of a pitch. You will add some tolerance to both major and minor diameter (I use +0.1mm per radius, or 0.2mm per diameter).

Once you've created profile (which is trapezoid with 60 degree sides - have a look here: https://en.wikipedia.org/wiki/ISO_metric_screw_thread, I don't bother with rounded bits as tolerance takes care of that) - you use subtractive helix on geometry that you already prepared (which is just some cylindrical shape).

There are a few youtube tutorials on how to do threads - both in freecad and fusion 360 - maybe have a look at those?

[Petrol]

On 03/10/2022 at 09:37, 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

Did you use a clip in filter on your 1100d to take this image?
Reason I ask is I have a modded 600d with the Samyang 135 attached and whiltst I'm in a bortle 5 area in Lancashire, I can't expose for 180 s because the image blows out over exposed.
I also have a RASA 8 with a ASI294MC OSC but that has a ZWO dual narrowband filter in it. Whilst it has a narrower FOV, I'm guessing the filter is taking most of the light pollution out because I can take 300s images with that no problem.
I'd love to get the 600d working properly with the Samyang because I want to take some widefield images on a second rig I'm building
Pete

[Elp]

180s at f2 or f3 unfiltered sounds like a lot, you're only going to pick up light pollution if it's also present around you. Any nearby light even if it's not hitting the lens will illuminate around your field of view. The 135mm lens is also quite curved so any light hitting it at an angle will make it worse.

[barbulo]

Wide-field rig almost finished. Waiting for the Samyang-to-M48 adapter from FLO to connect the 294+EFW. Some printed parts and some bits and bobs from the hardware store.

[Phillyo]

Another image with the SY135. More details can be found in the Deep Sky Imaging page.

About 14 hours of data, Risingcam IMX571, SY135, 60s exposures, EQ6-R Pro, L-Pro UV/IR filter. NINA and Pixinsight for software.

The bright glow is Mars....*facepalm*. I didn't even realise it was there until too late, but it is what it is.

Phil

[Laurin Dave]

Two panel mosaic of the lower part of Orion..  3hrs per panel, Samyang at f2.8, ASI2600mc, 300sec subs, Gain 0 Offset 76. Processed in Pixinsight and Photoshop.  Sharpened with Blur Exterminator and Noise reduced with Noise Exterminator, gradient minimised using Normalise Scale Gradient in Pixinsight.

Dave

Edited December 21, 2022 by Laurin Dave

[geeklee]

12 minutes ago, Laurin Dave said:

Two panel mosaic of the lower part of Orion..

Fantastic Dave.  Lovely dust & Ha of Barnards loop alongside some super detail throughout (for what must be ~12"PP in the presented image?).   

[beamer3.6m]

I previously purchased the Samyang 135mm (Canon mount) and I used it once and it worked well...

Unfortunately however, due to a multitude of reasons, I need to move this lens along... it is effectively brand new, fully boxed and comes with the lens pouch/bag and also a 3d printed bhatinov mask which I made.

I'm hoping to get back what I paid out as I need to recoup this ideally do I'm looking for offers around the £350 mark... its currently around £440 on Amazon...

Please pm if interested. I will put it in the for sale section shortly but thought best to post here amongst the specific users.

[Petrol]

On 21/12/2022 at 18:45, Laurin Dave said:

Two panel mosaic of the lower part of Orion..  3hrs per panel, Samyang at f2.8, ASI2600mc, 300sec subs, Gain 0 Offset 76. Processed in Pixinsight and Photoshop.  Sharpened with Blur Exterminator and Noise reduced with Noise Exterminator, gradient minimised using Normalise Scale Gradient in Pixinsight.

Dave

What an awesome image especially with OSC. I can only dream of doing something like this. What are your skies like and what filter did you use?

Pete

[Laurin Dave]

11 hours ago, Petrol said:

What an awesome image especially with OSC. I can only dream of doing something like this. What are your skies like and what filter did you use?

Pete

Thank you, skies are Bortle 4-5, no filter used (except the UV/IR cut on the camera) 

[stevelup]

My first nebula attempt, and I have to say I'm amazed.

Heart and Soul - Canon EOS600D (astro-modded) with Optolong L-eNhance filter. Samyang Lens was stopped down one click to F2.8.

180 x 30 seconds at ISO 800

I'm really, really happy with this considering it's my first ever attempt

 

 

 

 

[AstroFin]

Very impressive first results @stevelup ! A lot of detail visible there. You have also nailed the focus and the stars are round, meaning you have accurate tracking.

I had another go at Orion, this time capturing 171x60s frames with my modified Canon 6D under Bortle 2 skies.

Full size image in my AstroBin!

[Laurin Dave]

6 minutes ago, AstroFin said:

Very impressive first results @stevelup ! A lot of detail visible there. You have also nailed the focus and the stars are round, meaning you have accurate tracking.

I had another go at Orion, this time capturing 171x60s frames with my modified Canon 6D under Bortle 2 skies.

Full size image in my AstroBin!

 

Wow!

[stevelup]

@AstroFin Cheers - it exceeded expectations for sure. 

The original image was quite noisy with what I understand to be 'walking noise' which I've now read up on and it looks like I can mitigate by dithering.

I don't think it's poor polar alignment or bad tracking because as you said, the stars are perfectly round.

Also, I'm interested to know what people think about 180 x 30 sec -vs- let's say 90 x 60 sec. Assuming the tracking and alignment are good, do the longer exposures actually help.

Part of me wants to capture the same target again with dithering to see what difference it makes, but I might just do a different target instead and come back to this one.

 

[aleixandrus]

Can't coment on dithering as I've just did yesterday my very first light with the samyang and my new setup but from my almost-zero experiencie, it is worth it. This is the result of a quick-and-dirty processing of that very first light without calibration frames but using dithering:

 

Some info:

• Equipment: EQ6-R + ASI183mm Pro + Samyang 135 + EAF + EFW + LRGB filters + NINA
• 16L, 3R, 3G, 3B @ f2.8 @ 120s each (50min total), dithering after each sub, no guiding, no sub rejection, no darks, no bias, no flats, no noise reduction, no nothing, in summary. Bortle 4-5 (probably 5+ nowadays).
• Editing: Stacking, background extraction and channel combination in PixInsight. Some color saturation increase. (Note: I barely know how to use PixInsight 😅)

To be fair, the image is (quite) a bit so-so but I'm quite happy everything worked somehow together as this was ther first time all equipment was plugged at a time. In fact I had some issues with power and cabling management and also with humidity and cold (my laptop freeze 3 times in 2 hours span). I also have to improve the logistic as I lost count of how many trips inside-outside house I did 😂 Oh god, I need an observatory ASAP!

 

[geeklee]

Great first result @stevelup  Thanks for sharing the wider view and the close ups 👍  You've snagged a bit of the Double Cluster in the top right of the first image too! Only feedback (1) Definitely dither if you can and (2) be careful pushing the image enough that the noise reduction can get too strong - it's always a balance - noise, detail, stretch (and many other things)

2 hours ago, AstroFin said:

Full size image in my AstroBin!

Nice one Tomi - Loads to enjoy in that frame!

30 minutes ago, aleixandrus said:

I also have to improve the logistic as I lost count of how many trips inside-outside house I did

Excellent first light Alejandro.  I think a lot of us can sympathise with the logistics part - especially when you're starting out.  Don't worry, every trip out will reduce the number required next time! 😊

Edited December 27, 2022 by geeklee

[aleixandrus]

Thanks @geeklee! I got the mount one month ago and (as expected) it was rainy every single day and more rain is expected in the next 15 days at least. Yesterday I view a crearing in the sky so I jumped, unprepared at all, outside the house without a plan in mind... It was a miracle everything worked!

By the way... A general question: How long can you make the subs without guiding? With the EQ6-R I tested 120s ok for my standards but those at 240s were terrible (I may had messed up things), which is a bit dissapointed as I also achieved 120s with my StarAdventurer...

Edited December 27, 2022 by aleixandrus

[geeklee]

3 hours ago, aleixandrus said:

By the way... A general question: How long can you make the subs without guiding? With the EQ6-R I tested 120s ok for my standards but those at 240s were terrible (I may had messed up things), which is a bit dissapointed as I also achieved 120s with my StarAdventurer...

Perhaps you have a very good Star Adventurer and an average EQ6-R .  I'm not sure what the EQ6-R is capable of for unguided subs at this focal length with the small pixels of the 183MM (it might be worth you starting a new topic for this if you want a better answer).  I'm fairly sure my own AZEQ6 would struggle at 240s unguided.

For F2.8 with the Samyang on the ASI183 (unity gain), you likely don't need to expose LRGB for as long as 120s - certainly not on Luminance.

[Paul2019]

 

M45 between and through the clouds 30 x 120s subs. No time for flats because of the rain! Came out to the kit soaked. 
 

processed in pixinsight but only lightly as most of the tools I use didn’t like my data. 
 

still nice to get back out for a bit, really struggled recently with the weather 

[ollypenrice]

BLUR XTERMINATOR QUESTiON.

Has anyone tried BlurXT deconvolution on Samyang data? I only have a single sub so far and it doesn't produce a workable improvement, though it seems to be trying to do so. I think it might work on a stack. If you have a stack but don't have BlurXT (which needs Pixinsight as well) and would like to try it, Dropbox me the linear stack and I'll run it and send it back. PM me. The holy grail would be that it would fix corners with the lens wide open.

While we're on BlurXT, there's a PI script available here. https://www.skypixels.at/pixinsight_scripts.html  It installs in Script - Render and allows you to derive a PSF for you image and insert it manually into BlurXT instead of using the auto PSF. Some say this improves the result.

Olly

[Laurin Dave]

20 minutes ago, ollypenrice said:

BLUR XTERMINATOR QUESTiON.

Has anyone tried BlurXT deconvolution on Samyang data? I only have a single sub so far and it doesn't produce a workable improvement, though it seems to be trying to do so. I think it might work on a stack. If you have a stack but don't have BlurXT (which needs Pixinsight as well) and would like to try it, Dropbox me the linear stack and I'll run it and send it back. PM me. The holy grail would be that it would fix corners with the lens wide open.

While we're on BlurXT, there's a PI script available here. https://www.skypixels.at/pixinsight_scripts.html  It installs in Script - Render and allows you to derive a PSF for you image and insert it manually into BlurXT instead of using the auto PSF. Some say this improves the result.

Olly

Ive done a bit Olly, first attempt posted in this thread on 21st ..  it was on a stack of 2 hrs or so..   seemed to do a good job with the corner stars although I have subsequently noticed that it can turn stars with coma into edge on spirals! Also it seems to remove the colour from the stars, I suspect because the colour is in the halo and that is massively reduced by BXT..   I’m going to experiment as to whether it’s best to extract luminance,  BXT that,  then recombine with separately processed using star removal RGB 

Dave 

Edited December 29, 2022 by Laurin Dave

[ollypenrice]

1 hour ago, Laurin Dave said:

Ive done a bit Olly, first attempt posted in this thread on 21st ..  it was on a stack of 2 hrs or so..   seemed to do a good job with the corner stars although I have subsequently noticed that it can turn stars with coma into edge on spirals! Also it seems to remove the colour from the stars, I suspect because the colour is in the halo and that is massively reduced by BXT..   I’m going to experiment as to whether it’s best to extract luminance,  BXT that,  then recombine with separately processed using star removal RGB 

Dave 

The L extraction is a good idea. I tried something similar with partial success. (Placed a Blux image on top of the standard in blend mode luminance.)

Olly