Imaging with the Samyang 135mm f2

[mcg_photogrpahy]

On 20/06/2019 at 11:35, Kaydubbed said:

Ah I use a ZWO set for now at 7nm  with my asi183mm and noticed my frames were soft in Ha detail on NGC7000 but I totally just blamed the poor transparency.  I should stop to F4 and see if I have improvements. I'm sure it will improve but k already regret that loss of light at F4!

Any update? I have the exact same camera/ filters and I'm about to get the 135mm

[Space Oddities]

This might be of interest if you want to use ZWO's EAF with the Samyang. Really nice mounting system!  

I will give it a try with a timing belt instead of the toothed gear. This way I could share this system between the RedCat and the Samyang, while having only 3 screws to remove.

Edited May 7, 2021 by Space Oddities

[geeklee]

42 minutes ago, Space Oddities said:

This might be of interest if you want to use ZWO's EAF with the Samyang. Really nice mounting system!  

Nice one Pierre, I've been reading your updates in the main post.  Gear to gear looks like a little backlash would be there but with the belts perhaps less, especially thinking about the fine focusing margins of the Samyang when wide open (or close).

Edited May 7, 2021 by geeklee

[Space Oddities]

Yes, I need to test this once I receive the other toothed gear. But so far it seems pretty tight and doesn't seem to be too much backlash...

Let's see, it's my first focus motor, so I'm not very familiar with this technology yet! I feel like a caveman discovering the joy of having a zippo...  

The timing belt might indeed be a cheap way to adapt this kit to the Samyang. I've found a seller on Amazon Germany that provides custom size belts, so that would be perfect. There is room to adjust the bracket's position laterally, which is perfect to adjust the tension of the belt, or distance from the toothed gear to the toothed ring.

[geeklee]

24 minutes ago, Space Oddities said:

Yes, I need to test this once I receive the other toothed gear. But so far it seems pretty tight and doesn't seem to be too much backlash...

Let's see, it's my first focus motor, so I'm not very familiar with this technology yet! I feel like a caveman discovering the joy of having a zippo...  

Most capture applications can compensate for backlash - either with "overshoot" type approach or calculating actual values.  Was just thinking out loud more than anything on whether there was much and if that would be a pain in applications trying to get into such a small focus zone.

I felt like autofocus was the last step to my RedCat being fully automated and it made such a difference.  Still contemplating ways to introduce this to the Samyang - having seen so many good ideas on here.  I'd already bookmarked a belt and pulley based on @Adreneline's previous Samyang system (and current RedCat one).

Edited May 7, 2021 by geeklee

[desmcm]

To mount the ZWO EAF I mostly followed the excellent design here:

https://www.thingiverse.com/thing:4761672

Big thanks to Dale. Please note that I found I had to scale everything up by 2% and then used electrical insulation tape to shim the focus ring. This may depend on the vagaries of the 3D printer used. Dale's design is particularly nice as it allows the belt tension to be adjusted easily by moving the EAF in or out.

All seems to work well with the ASI AIR - attached is the very first auto focus run. My back spacing currently is 27.3 + 17.5 mm (ASI2600MC) with infinity focus just to the left of the L (with an Optolong L Pro in place.). Should I add another 0.2mm? Please advise. Stars are not completely round in the corners, mainly bottom right. Tilt? Might be hard to tune out so probably best not to look!

Thanks to everyone for help along the way.

Des 

[geeklee]

2 hours ago, desmcm said:

Should I add another 0.2mm? Please advise.

I think at that marking (just shy of the L) I've seen even a 0.1mm spacer push it all the way to the end stop (to the right).  Although mine hard stops just after the L (on the right) and not at the infinity marking - not sure if this is normal!

That looks like a really nice setup Des.

[geeklee]

A little spring fun from the other night. Two pane mosaic of the Sadr region taken with 7nm Baader Ha @ ~F2.8.  Left side is 42 minutes, right side 30 minutes.

Edited May 7, 2021 by geeklee

[Adreneline]

12 hours ago, geeklee said:

A little spring fun from the other night. Two pane mosaic of the Sadr region taken with 7nm Baader Ha @ ~F2.8.  Left side is 42 minutes, right side 30 minutes.

Very nice Lee - another excellent  Ha image from the Samyang. Mine is now permanently attached to the ASI294MC complete with EAF belt drive and my ASIair-original ; it’s very light weight. I’m itching to try it alongside the RedCat+ASI1600MM narrowband rig. Just need a clear albeit short night!

[Adreneline]

My latest Samyang configuration. The 294 has an Astronomik L2 filter fitted in the 11mm spacer and the 135 focuses in the middle of the ‘L’.

Adrian

[geeklee]

6 hours ago, Adreneline said:

Mine is now permanently attached to the ASI294MC complete with EAF belt drive and my ASIair-original ; it’s very light weight. I’m itching to try it alongside the RedCat+ASI1600MM narrowband rig. Just need a clear albeit short night!

 

6 hours ago, Adreneline said:

My latest Samyang configuration.

Looks great Adrian - very solid setup.  With new moon coming up, hopefully you'll get a chance to try everything out.

[Adreneline]

28 minutes ago, geeklee said:

With new moon coming up, hopefully you'll get a chance to try everything out.

.... or there again, perhaps not!  

I'll be good and ready for the return of astro-darkness in late July that's for sure

Adrian

 

[Chefgage]

NGC 7000 North America Nebula

Capture information

Star Adventurer pro
ASIAIR Pro
Samyang 135mm lens (at F3)
Canon 200D (modified)
Astronomik Ha filter (12nm)
ZWO ASI120mm mini guidscope

ISO 800
EXP 300s
Lights 34
Darks 0
Flats 20
Bias 20

Moon percentage 21% Moon below horizon

Apologies, also posted in the deep sky section and star adventurer pro section.

[Rush]

Dear mates,

my  recent attempt with Samyang 135mm on Dolphin nebula with Optolong L- extreme filter  and a Sony A7 camera.

CS

Rush

Optolo-eXtreme

[geeklee]

It's been a while coming, but I've finally pulled together the various bits to add a ZWO EAF to my Samyang.  Thanks everyone for the inspiration and help on varied rigs and 3D printing!  

I currently have the Astrokraken rings, so I removed the top plate and designed a simple replacement that could hold the ZWO EAF with ability to raise it up for tensioning a belt.

Then a - hopefully - robust way to get the belt tensioned around the lens.  I've seen various designs and adapted a few ideas to create a two piece ring that would join with an M3 nut and bolt (rudimentary, I know).  This was for a GT2 belt but the HTD 3M one I did worked fine too.

The rig now looks like this.  Excuse the right hand dovetail - I need to rework this.

Here's the ZWO EAF mounted on the custom bracket (very solid):

Here's the belt and geared rings:

The gear meshing is good on the pulley and round the lower ring.  The upper ring is tricky as it has to match very closely to get good mesh.  Mainly I want to just keep the same distance as the pulley moves - a few earlier iterations of a half ring only proved a mistake.

Hopefully someone finds this as useful as I've found the ideas in this thread.

Testing it all out...and like a broken record as I have a similar image up above in the thread.... here's a 3 pane mosaic of the Sadr region during civil darkness in Ha (~F2.4).  Each pane is 30 minutes (10 x 180s).  I wasn't sure how to present it as vertical looks cool, but the below fits better... 

 

[Adreneline]

56 minutes ago, geeklee said:

The rig now looks like this.  Excuse the right hand dovetail - I need to rework this.

Looks really good to me. I find it interesting to see how people evolve their rigs. How easy do you find it to balance on the mount? I presume your Samyang weighs quite a bit more than the mini guide scope.

I have thoughts about using my Samyang RGB rig alongside my RedCat NB rig. So far I've found it very hard to get it perfectly balanced on the iOptron. The RedCat and Samyang as configured weigh nearly the same but I find it really tricky to balance in DEC.

Adrian

[geeklee]

9 hours ago, Adreneline said:

I find it interesting to see how people evolve their rigs. How easy do you find it to balance on the mount? I presume your Samyang weighs quite a bit more than the mini guide scope.

Me too.  My AZ EQ6 is quite stiff so I don't get that lovely easy to balance RA/DEC I see where a few mm makes the difference  This setup is actually better as it's heavier overall which makes it easier to balance in RA.  For DEC - it's balanced in two directions.  It sits horizontal by default with scope pointing up (of course) and it's slid to the right significantly as you allude to above.  The blue bit of tape in the top image is a marker for the right hand clamp in the saddle so the Samyang part ends up just off centre to the left.  Then turn the DEC so the scope points to the left or right and balance by sliding the dovetails along their individual clamps.  

I could probably look at moving the clamps towards the centre of the bar more... 🤔

Weighing in at 4.2kg it's far within the AZEQ6 capabilities that I don't worry too much esp with the imaging scale being high.

9 hours ago, Adreneline said:

I have thoughts about using my Samyang RGB rig alongside my RedCat NB rig. So far I've found it very hard to get it perfectly balanced on the iOptron. The RedCat and Samyang as configured weigh nearly the same but I find it really tricky to balance in DEC.

Same here 🙂  I've had it hooked up on the bench like this.  Your mount must be one where those few mm make the noticeable difference.  Is it one particular DEC axis it struggles with?

Edited June 2, 2021 by geeklee

[Adreneline]

1 hour ago, geeklee said:

Is it one particular DEC axis it struggles with?

Not really. The slightest movement across the DEC axis in either of the orthogonal directions and it's winging its way off. The CEM25 is extremely free-moving and it is quite difficult to incrementally slide the rigs in the Vixen clamps. I've used the tape approach too - but it doesn't help that I keep tinkering and modifying  

[Spongey]

A little update on my Samyang adventures! After almost a whole month of rain we've had some clear skies so I was able to get out and take some Ha data on IC1396. Losing astro-dark last week isn't ideal but I have found that narrowband in nautical dark / astro twilight is still acceptable (particularly towards the middle of the night). This is 3 hours from the other night:

The framing isn't the best but I was only aiming for the central target. I've included the full frame to show people what can be expected with this camera/lens combo!

[geeklee]

2 hours ago, Spongey said:

The framing isn't the best but I was only aiming for the central target. I've included the full frame to show people what can be expected with this camera/lens combo!

Great image @Spongey What a fantastic FOV with that camera and the quality of stars for such a view is excellent.

[nephilim]

On 01/06/2021 at 22:55, geeklee said:

It's been a while coming, but I've finally pulled together the various bits to add a ZWO EAF to my Samyang.  Thanks everyone for the inspiration and help on varied rigs and 3D printing!  

I currently have the Astrokraken rings, so I removed the top plate and designed a simple replacement that could hold the ZWO EAF with ability to raise it up for tensioning a belt.

Then a - hopefully - robust way to get the belt tensioned around the lens.  I've seen various designs and adapted a few ideas to create a two piece ring that would join with an M3 nut and bolt (rudimentary, I know).  This was for a GT2 belt but the HTD 3M one I did worked fine too.

The rig now looks like this.  Excuse the right hand dovetail - I need to rework this.

Here's the ZWO EAF mounted on the custom bracket (very solid):

Here's the belt and geared rings:

The gear meshing is good on the pulley and round the lower ring.  The upper ring is tricky as it has to match very closely to get good mesh.  Mainly I want to just keep the same distance as the pulley moves - a few earlier iterations of a half ring only proved a mistake.

Hopefully someone finds this as useful as I've found the ideas in this thread.

Testing it all out...and like a broken record as I have a similar image up above in the thread.... here's a 3 pane mosaic of the Sadr region during civil darkness in Ha (~F2.4).  Each pane is 30 minutes (10 x 180s).  I wasn't sure how to present it as vertical looks cool, but the below fits better... 

 

Thats a really smart little set up mate. I've been looking at the EAF as a future purchase although not for a while yet. Ive been wondering how i'd mount it though as i'm using the Evoguide ED50 as my guide scope & dont intend changing that, so my only other option will be dual side by side mounting with the Samyang & 533 on one side & the Evoguide on the other but i'm pretty loathe to spend £217 on a blooming ADM Losmandy Type D base plate, but I dont see any other option.
I've still to even get started with my first session yet if you can believe that . I was furloughed for over a year & very much looking at potential redundancy but thankfully i've kept my job (out of over 25 staff members only myself & one other kept our jobs, although we are both managers. Anyway work slowly started back up again a couple of months ago & its been non stop since. That will all start to get back to its normal pace soon & i'll finally be able to get up & running but its been very frustrating after spending all those months saving & slowly buying gear only to finally have it but no time to actually use it (The photos show how far i've got so cable managements is next on the cards). It'll be happening very soon though 😃
Btw your image of the Sadr Region is stunning 

[Space Oddities]

You could use the cheaper dual plate from TS Optics, There should be enough room for an EAF between the lens and the Evoguide: https://www.teleskop-express.de/shop/product_info.php/language/en/info/p8315_TS-Optics-Parallelbefestigung---Doppelbefestigung-fuer-Teleskope--Tele-und-Leitfernrohre.html

 

[geeklee]

11 hours ago, nephilim said:

The photos show how far i've got so cable managements is next on the cards). It'll be happening very soon though 😃

That sounds like a very challenging time during those months, waiting to hear what would happen at work.  On the kit side, with a few cables that looks ready to go.  With a Bahtinov mask, you should be fine with the occasional check - focus seems to hold well.  It's tricky at the moment - testing things out means staying up late and if there's any troubleshooting - that can be tough as the early hours come round (speaking from experience!)

11 hours ago, nephilim said:

but i'm pretty loathe to spend £217 on a blooming ADM Losmandy Type D base plate, but I dont see any other option.

I was lucky to pick mine up second hand on SGL a while back.  It's the vixen only one I have in the photo, so less cost than the dual one - which you shouldn't need with vixen dovetails only.  I had intended it for another project but changed my mind... was just about to try and sell it on, when I put the Samyang on it.

Good dual option from @Space Oddities above. 

There's also an all in one solution above by @desmcm although it requires 3D printed parts + other bits (all described on the link provided).  I'm still thinking about switching to this 🙄 😁

[nephilim]

16 hours ago, Space Oddities said:

You could use the cheaper dual plate from TS Optics, There should be enough room for an EAF between the lens and the Evoguide: https://www.teleskop-express.de/shop/product_info.php/language/en/info/p8315_TS-Optics-Parallelbefestigung---Doppelbefestigung-fuer-Teleskope--Tele-und-Leitfernrohre.html

 

@Space Oddities That looks a far more reasonable option price wise, thanks for the link 🙂

[nephilim]

7 hours ago, geeklee said:

That sounds like a very challenging time during those months, waiting to hear what would happen at work.  On the kit side, with a few cables that looks ready to go.  With a Bahtinov mask, you should be fine with the occasional check - focus seems to hold well.  It's tricky at the moment - testing things out means staying up late and if there's any troubleshooting - that can be tough as the early hours come round (speaking from experience!)

I was lucky to pick mine up second hand on SGL a while back.  It's the vixen only one I have in the photo, so less cost than the dual one - which you shouldn't need with vixen dovetails only.  I had intended it for another project but changed my mind... was just about to try and sell it on, when I put the Samyang on it.

Good dual option from @Space Oddities above. 

There's also an all in one solution above by @desmcm although it requires 3D printed parts + other bits (all described on the link provided).  I'm still thinking about switching to this 🙄 😁

@geeklee Yes, it was a bit of a tough time especially as I like my job which is a rare thing these days but now that worry is out of the way I can make a start on the AP (once work has eased off a bit as theres a lot of things to catch up with after been closed down for over a year)
I think i'll go with the TS Optics Dual plate that @Space Oddities kindly linked above as it looks ideal for my set up & at a really good price. I bought a dedicated Bahtinov mask for the 135 as part of a package with the Samyang mounting kit which is why I can put off buying the EAF for a while (I'll probably wait until winter for that.

As you mentioned, its harder now with the lighter nights but it has one advantage for me. It'll give me plenty of time (on warmer summer nights) for getting everything working, ironing out any issues & getting a good efficient routine sorted for setting up quickly when those cold winter nights come around as from past experience I know theres nothing worse than having to try & sort out problems in sub zero conditions. Thanks for your input 🙂