Imaging with the Samyang 135mm f2

[Chefgage]

Heart and Soul Nebula's in Ha.

Star adventurer pro
ASIAIR pro
Samyang 135mm lens
Canon 200D modified
Astronomik Ha filter (12nm)
ZWO ASI120mm mini guide scope

ISO 800
EXP 300s
Lights 24
Darks 15
Flats 40
Bias 40

Moon percentage 89%
Half way through image session moon angular distance 70° 40' 08.3" 

Total exposure time 2 hr 

[Hallingskies]

Sh2-273, Atik 460, Baader 7um Ha filter, f2.8. 10 x 600s under a full moon...

Edited March 5, 2021 by Hallingskies
samyang 135 f number added

[Chefgage]

I have just re-processed the heart and soul nebula's I posted one before the last post above.  De-cropped and then re-processed. Same capture information.

 

[geeklee]

A few OSC images taken on and off during February 2021.  All with Samyang 135 (@ F2), ASI533 and UVIR filter. Most can click through for slightly bigger versions.

M44 (42 minutes)

Virgo Galaxy Cluster - 2 panel mosaic (85 minutes per panel)

A very small M101 (70 minutes)

M42 and M43 (102 minutes)

A very cloudy (wrong sort of cloud though) Orion - 4 panel mosaic (15 minutes per panel)

Clear skies

Edited March 8, 2021 by geeklee

[Mark1489]

I’ve been waiting a long time to get my samyang out again, I finally had an opportunity last month on the Pleiades. I’ve started autoguiding my star adventurer due to so many problems with periodic error, I wish I’d decided that earlier! 
73 x 90s at f/2.8, ISO 400

Nikon D5600a

Bortle 4 sky

Edited March 8, 2021 by Mark1489

[Chefgage]

9 hours ago, Mark1489 said:

I’ve been waiting a long time to get my samyang out again, I finally had an opportunity last month on the Pleiades. I’ve started autoguiding my star adventurer due to so many problems with periodic error, I wish I’d decided that earlier! 
73 x 90s at f/2.8, ISO 400

Nikon D5600a

Bortle 4 sky

Very nice image. There was a few targets I was determined to get this winter. I managed the others but not the Pleiades. Whenever it was clear skies there was always a fullish moon. Coupled with my bortle 8 skies makes this difficult. I did however have a session on it regardless of the full moon. Processing wise I managed to tease out some nebula but the overall image came out poor. Never mind I will try again

[Knight of Clear Skies]

A couple of recent Samyang images.

Stars of Cygnus, I wasn't sure what I wanted to image so I just framed up some dark nebulae in Cygnus. Turns out the emission nebula is the Tulip.

Just a ten-second snap of M31, surprised how much of the galaxy it caught at f2. Reason I was taking such short exposures was to make this animation, I didn't want to blur out the tree too much.

[Mark1489]

12 hours ago, Chefgage said:

Very nice image. There was a few targets I was determined to get this winter. I managed the others but not the Pleiades. Whenever it was clear skies there was always a fullish moon. Coupled with my bortle 8 skies makes this difficult. I did however have a session on it regardless of the full moon. Processing wise I managed to tease out some nebula but the overall image came out poor. Never mind I will try again

Thank you! I can relate with those clear skies and full moons! Keep at it and get as many photons as you can, you’ll get the image you want if you just go flat out with the total integration time I’m sure! 

[Chefgage]

18 minutes ago, Mark1489 said:

Thank you! I can relate with those clear skies and full moons! Keep at it and get as many photons as you can, you’ll get the image you want if you just go flat out with the total integration time I’m sure! 

I seem to find myself always doing sessions in Ha due to the moon as I know I will get a good image that way. With work the next morning most times, I seem to be getting only about 2 hours worth of RGB when the moon is away in those rare occasions. I need to start getting data from multiple nights or find a way to persuade the clouds to go away at the weekend. Anyone know how to bribe clouds???

Edited March 9, 2021 by Chefgage

[Hallingskies]

Sh2-273 in HaRGB, 10 x 600s each channel, Samyang 135mm @f2.8, Atik 460/EFW2... 

[desmcm]

Thanks to everyone who has posted in this thread so far, as it has all been very helpful in putting together my rig. I thought it might be helpful to others to share some of my (limited) experience so far, and to ask for comments on whether the performance of my 135 is in keeping with what one might typically expect.

First a few words on the rig:

- I opted for a Redcat 51 mounting ring as suggested by many others. This seems to hold the lens nice and snug and my preliminary assessment is that it is a good choice.

- The Astro Essentials M48 replacement plate was easy to install and seems well made.

- As I am using a ZWO filter drawer (21mm optical path length), and an ASI2600MC Pro (17.5 mm back spacing required), I decided to use an M48 extension tube to get me to the required 44mm. First attempt was to try the Astro Essentials extension tubes available from FLO. This turned out not to work particularly well as the female thread on the extension tubes were not deep enough to take the male M48 thread on the lens plate. A better option seems to be to use the TS M48 5mm extender (https://www.365astronomy.com/ts-optics-2-inch-extension-tube-with-double-sided-2-inch-filterthread-5mm-length). This gets me very close, within a 1mm, of the required back focus with everything nice and firmly attached.

First light was (surprise, surprise) the Orion complex as shown in the image: f2  21 x 120s lights, 50 flats, 50 dark flats, gain 100, -10C sensor temp. I am delighted with the result at f2, with perhaps the focus being a little soft.

Looking at the variation of the FWHM and eccentricity it is difficult to know whether the lens is performing to spec (me, the imager, most certainly is probably not) so constructive feedback welcome.

Thanks in advance,

Des

 

Edited March 18, 2021 by desmcm

[desmcm]

On 25/02/2021 at 14:46, Space Oddities said:

I have found on Aliexpress a very cheap mask, that seems less coarse than standard Bahtinov masks. You might have to pay some import duties (ships from China), but for that price, it might be worth considering!

 

Hi Pierre, BM finally arrived. I paid about £10 including shipping. It seems to work reasonably well, and the construction quality is reasonable for the price.

Attached is a comparison of its performance against one acquired from the very helpful Lucas at https://astrojolo.com. The star I believe is Polaris.

The  images were taken in quick succession, first the one from aliexpress, and then the one from astrojolo. The fact that the focus was a little bit off seems more evident in the latter, which will be my first choice going forward, but both seem to perform well.

 

[Richie092]

1 hour ago, desmcm said:

Thanks to everyone who has posted in this thread so far, as it has all been very helpful in putting together my rig. I thought it might be helpful to others to share some of my (limited) experience so far, and to ask for comments on whether the performance of my 135 is in keeping with what one might typically expect.

First a few words on the rig:

- I opted for a Redcat 51 mounting ring as suggested by many others. This seems to hold the lens nice and snug and my preliminary assessment is that it is a good choice.

- The Astro Essentials M48 replacement plate was easy to install and seems well made.

- As I am using a ZWO filter drawer (21mm optical path length), and an ASI2600MC Pro (17.5 mm back spacing required), I decided to use an M48 extension tube to get me to the required 44mm. First attempt was to try the Astro Essentials extension tubes available from FLO. This turned out not to work particularly well as the female thread on the extension tubes were not deep enough to take the male M48 thread on the lens plate. A better option seems to be to use the TS M48 5mm extender (https://www.365astronomy.com/ts-optics-2-inch-extension-tube-with-double-sided-2-inch-filterthread-5mm-length). This gets me very close, within a 1mm, of the required back focus with everything nice and firmly attached.

First light was (surprise, surprise) the Orion complex as shown in the image: f2  21 x 120s lights, 50 flats, 50 dark flats, gain 100, -10C sensor temp. I am delighted with the result at f2, with perhaps the focus being a little soft.

Looking at the variation of the FWHM and eccentricity it is difficult to know whether the lens is performing to spec (me, the imager, most certainly is probably not) so constructive feedback welcome.

Thanks in advance,

Des

 

Hi. I'm in the process of trying to get my 135 to the correct backfocus so whilst I can't help you at the moment could you please tell me what software you are using to analyse your images?

Ta

 

[desmcm]

19 minutes ago, Richie092 said:

Hi. I'm in the process of trying to get my 135 to the correct backfocus so whilst I can't help you at the moment could you please tell me what software you are using to analyse your images?

Ta

 

Pixinsight

Best, Des

[Richie092]

Thanks Des. Is that a script? Process?

 

[doubledoubleswifty]

On 02/03/2021 at 15:09, Richie092 said:

I bottled it and ordered from Amazon. It is sitting in front of me with the Atik EFW and 383l+ hanging off the back of it waiting for first light.

Hopefully get an hour tonight to see if I have the spacing right. M48 to M53 Adaptor 2mm -> Atik EFW2 22mm -> Atik 383L 17.5mm = (2 + 22 + 17.5) = 41.5mm (+/- 0.5mm) I may need to space it out a bit but will see.

Hopefully yours will turn up soon. What are you using it with?

It finally arrived today!

Ordered 20th of February.

Arrived 18th of March.

On quick inspection - no major problems seen 🙂

[Richie092]

7 minutes ago, doubledoubleswifty said:

It finally arrived today!

Ordered 20th of February.

Arrived 18th of March.

On quick inspection - no major problems seen 🙂

The gamble paid off. Well done.

[desmcm]

3 hours ago, Richie092 said:

Thanks Des. Is that a script? Process?

 

https://pixinsight.com

One of the most popular astrophotography programs for pre and post processing. For many people including myself it is a one-stop shop that does everything I need.

Steep learning curve, worth it in my opinion, supported by many excellent video channels on youtube.

Best, Des

[Richie092]

Sorry Des. I didn’t make my answer very clear

I have and use PI, the basics of it for now, I just didn’t know what script or process you used in it for that information. 

[desmcm]

9 minutes ago, Richie092 said:

Sorry Des. I didn’t make my answer very clear

I have and use PI, the basics of it for now, I just didn’t know what script or process you used in it for that information. 

Sorry...

Script -> Image Analysis -> FWHMEccentricity

Run this having first separated your RGB image - if that is what you have - into R,  G, B channels.

Then select the channel to view, press Measure and then Support for the contour maps.

The latter only works if it can find enough stars so need a sub of reasonable exposure length eg 120s.

Cheers, Des 

[Richie092]

Thanks Des. I think I finally have my spacing right and it looks like I might get an hour to test it this evening so that really helps. 

[Mark1489]

Hi everyone,

Does anyone have any experience running the Altair HyperCam 183c pro tec with the samyang? I’m looking to get this camera for a lower pixel scale. Obviously cooling another added benefit! Apologies if I’ve missed any posts on this thread who has this setup! 
 

Mark

[nephilim]

Another camera/ Samyang question i'm afraid.

I'm finally buying the last piece of gear for my AP set up on Friday, the camera & have been looking at buying is the Zwo Asi 533. As the time gets nearer to buying i've stupidly started looking at other options as well & my other choice maybe the ASI 294MC Pro, does anyone use the Samyang with the 294 & is it a good fit? Are there any advantages over the 533? I know the 533 has zero amp glow but this can be dealt with  calibration frames if I went for the 294. My main concern with the 294MC Pro is the severe under sampling @7.07 although the resolution  with the 533 is @5.74 "/pixel & has good results.  This will be my first dedicated CMOS camera hence the chopping & changing with thoughts.
I'm only looking at ZWO cameras as i'll be using the ASIAIR to control everything.

Thanks.

[Adreneline]

9 minutes ago, nephilim said:

does anyone use the Samyang with the 294 & is it a good fit?

I've just started using a ASI294MC-Pro with my Samyang 135mm and so far I've been pleased with the results.

That said I've been using it to try to image IFN where I am not so bothered about the undersampling - pixel peeping at the stars can be disappointing. I also wanted to be able to capture RGB stars etc. to combine with my RedCat NB imaging rig using a ASI1600MM-Pro.

I also bought the 294 because I also own a StellaLyra 6" RC (f9) and the larger pixel size and sensitivity is a good match.

You never know what you might buy in the future!

Adrian

P.S. This is my latest attempt at IFN - it is nothing to write home about or show on the Imaging forum but it will allow you to see how the stars look. The image is 51 x 120s exposures, gain 120, default offset, temp -20 degrees. There is only minimal edge cropping and my flats needs som work (I think). Two hours barely starts to show the IFN - I think another 20 might be required!

There is no guiding on this image - I'm relying on the CEM25-EC to perform well with a light very well balanced payload.

HTH

Edited March 23, 2021 by Adreneline
Clarification

[Magnum]

1 hour ago, Adreneline said:

I've just started using a ASI294MC-Pro with my Samyang 135mm and so far I've been pleased with the results.

That said I've been using it to try to image IFN where I am not so bothered about the undersampling - pixel peeping at the stars can be disappointing.

 

Are you sure you have the spacing correct ? and what f stop are you using as my copy of the lens seems to give perfect pinpoints into the corners using same size sensor, as long as I stop it down to f2.8.

Great image anyway, I tried this a couple of weeks ago but picked up no IFN at all, im in Bortle 5 but live right next to the motorway so never sure if the IFN is getting washed out even if I use a light pollution filter. or maybe I just need a huge number of hours on it.

Lee