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Uranium235

Imaging with the Samyang 135mm f2

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Thanks Adrian, and thanks for your help.

Carole 

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One more image:

Bit of a struggle to image and process from Bortle 8 and the London Pollution and sky glow, but no choice ATM

IC405 and IC410 + IC417

Atik460EX and Samyang 135mm F2.8
Ha 17 x 600
Ha 4 x 900
Oiii 13 x 300 Binned x 2
Sii 13 x 300 Binned x 2
RGB 7 x 150 each
Total 6h 32mins Taken over 2 evenings

Combined as RHa, GOiii, BSii

spacer.png

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Carole, which brand of filters are you using?

So if you are almost in center of London and you call it as Bortle 8, then from my yard can i call it Bortle 7 although the LP map said it is Bortle 8/9?

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16 hours ago, carastro said:

One more image:

Bit of a struggle to image and process from Bortle 8 and the London Pollution and sky glow, but no choice ATM

IC405 and IC410 + IC417

Atik460EX and Samyang 135mm F2.8
Ha 17 x 600
Ha 4 x 900
Oiii 13 x 300 Binned x 2
Sii 13 x 300 Binned x 2
RGB 7 x 150 each
Total 6h 32mins Taken over 2 evenings

Combined as RHa, GOiii, BSii

spacer.png

That's a stunning looking image!

After seeing both pictured in Astronomy Now, I really wanted to have a go at them myself, but regrettably they're slipping from my viewing window for this season.  However, the fact that you've used a 135mm lens indicates these are quite large, and maybe not really suited for telescopes, unless they have a very wide field of view ?

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1 hour ago, Erling G-P said:

That's a stunning looking image!

After seeing both pictured in Astronomy Now, I really wanted to have a go at them myself, but regrettably they're slipping from my viewing window for this season.  However, the fact that you've used a 135mm lens indicates these are quite large, and maybe not really suited for telescopes, unless they have a very wide field of view ?

This target need almost minimum 300mm if you use a small sensor such as ASI1600, but if smaller sensor then 200mm, otherwise if you want to use something like 300-400mm then something like APC-S or full frame will fit this target nicely.

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This is ~150 mins of Ha collected last night using the Samyang 135mm and ASI1600MM-Pro; gain 139, offset 50, exposures of 180s x 147. Calibrated and integrated in APP, processed in PI and finished in PS.

First successful attempt with the ZWO mini guide scope (finally got it focussed) and ASI120 mini combination providing guiding better than 0.5". ASIair set to dither every three frames but for reasons I don't understand it did nothing like that. Whatever the end result is not too bad.

Minimal cropping just to remove edge effects.

CED 214

870777528_CED214-Ha-gd_8820s_dc_ABE_HT_LHElevelsdfine2.thumb.png.69ad6717306add51c5f7bde191b9411d.png

Not sure when conditions will be right to grab some OIII so Ha will have to do for now.

Adrian

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My coloured version of the NAN and Pelican Nebulae:

 

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When i see people keep imaging with just standard gear and maybe not astro things and being fine with their results i feel like i should really slow down with my mind, i only keep looking at high quality results from people with amazing gear and expensive and feel like "I will never be good until i reach their levels", but i think i have to find kind of a connection between going higher and enjoying my moment as well, and i don't want to end up with just something i have now that it won't last long or get me far and keep using it forever because people are telling me never look far or high and stay where you are, i like to move and walk quick not slow, so if they asking me to slow down or stay where i am then for how long?

I used my Canon 135mm for the first time in February, and since that time i didn't do any imaging, and i still didn't process my data, not sure how they will be, and i feel like should i buy another 135mm lens at least from Samyang for example because people here are enjoying using it or not?!!!

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On 16/03/2020 at 09:08, Adreneline said:

The ASIair continues to perform faultlessly and has transformed an imaging session for me. There are a few things I'd change but the ease of focussing with a BM and the iPad pinch-zoom display is amazing; APP reported every sub with FWHM of ~1.25. Plate solving and mount syncronisation saves so much time and gaurantees repeatability in seconds

I had one of these lenses ages ago but had to sell it before I got a chance to use it. This thread (and in no small part your stunning images Adrian) have persuaded me to order another one, and I'm pondering the relative merits of the astrokraken/astrojolo mounting and manual focusing solutions, though my plan long terms is to go ASI air with the ZWO eaf.  I was therefore wondering where you sourced your belt drive and bits for the focuser - did you make them yourself or is it produced somewhere as I couldn't find it? I'm also encouraged to hear platesolving is ok as I was thinking images with that much going on might require a bio computer to solve! Did you use anything for solving before the asiair? I'm assuming my APT platesolving should work what do you think?

Thanks, Andy

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Posted (edited)
47 minutes ago, Notty said:

This thread (and in no small part your stunning images Adrian) have persuaded me to order another one

Thank you Andy - that's very kind of you. It is an excellent lens and every bit as good as my more expensive Canon 200mm.

47 minutes ago, Notty said:

I'm pondering the relative merits of the astrokraken/astrojolo mounting and manual focusing solutions, though my plan long terms is to go ASI air with the ZWO eaf.

I tried (and subsequently sold) the AstroKraken solution. It works very well but I found it is a little fiddly to achieve a good level of focus. Without a doubt the Astrojolo (or the equivalent sold by FLO) is a must in my opinion as it pretty well totally solves the issue of droop and/or misalignment in the optical train. I have tried most of the EoS adapters and found the best one to be the ZWO solution but it is still not as good as the M42 screw solution offered by Astrojolo and others.

I have found the EAF to be excellent; I have found focus positions to be repeatable and it only takes a moment to refocus between filters (which I now change manually anyway). The belt and toothed pulley were both purchased from Motionco. I have to admit that I purchased a separate belt which I butchered so I could stick it to the focussing ring on the lens. I decided I would do this as I bought the Samyang purely for astro imaging; I decided a similar step was a step too far with the Canon which I also use on my dslr for regular photography.

47 minutes ago, Notty said:

I'm also encouraged to hear platesolving is ok

Plate solving with the ASIair is a dream, especially when linked to Sky Safari on the iPad. I have used plate solving with SGPro but not without some problems. I've never had plate solving on the ASIair fail; it typically takes just seconds to complete and sync the mount. I have no experience of using APT but by all accounts many people have used it very successfully.

I love using the Samyang 135mm - I love the wider fov and seeing these targets in their surrounding space.

If there is a downside to the lens it is that star shapes are not perfect at the extremes of the image (especially corners) but they are no worse than my Canon. By the time you have cropped of edge effects most of the dodgy stars have gone too!

Good luck!

P.S. I think @Ginasolution of using two 135mm in tandem looks a great idea - I would love have two 135's and two 1600's with a Ha and OIII filter capturing at the same time. That's what dreams are made of ;)  Dream on :(

 

Edited by Adreneline
Additional text
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Posted (edited)
1 hour ago, Adreneline said:

I love using the Samyang 135mm - I love the wider fov and seeing these targets in their surrounding space.

Agreed, I find these views convey the absolute immenseness(!?) of the universe way better than my ED80!

Thank you so much for the kit tips. I don't suppose you still have the specifications of the pulley and belt you ordered from motionco just so I'm primed when I can get the eaf?  I can't find anything on FLO which resembles the astrojolo kit, but maybe I'm searching wrong.

ASIair is an infuriating proposition to me at the moment.  I'd get it today if it supported any old ascom guide camera. I kind of get it that they want to tie you in to their kit, but what I can't forgive them for it not supporting their own 120mm which to me is their affordable guide camera. Unforgiveable!

1 hour ago, Adreneline said:

P.S. I think @Ginasolution of using two 135mm in tandem looks a great idea - I would love have two 135's and two 1600's with a Ha and OIII filter capturing at the same time. That's what dreams are made of ;)  Dream on :(

To be honest I'm seriously considering one day getting another 135 and paralleling my 1600mm for NB and my EOS6D for osc targets. There literally is no limit to how much money this hobby can take from me even at the budget end!

Edited by Notty

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Posted (edited)
31 minutes ago, Notty said:

I don't suppose you still have the specifications of the pulley and belt you ordered from motionco just so I'm primed when I can get the eaf?

I don't seem to have the order details anymore but you need to mount the EAF and then measure the length required to go round the lens and pulley you choose for your mounting arrangement. I'm pretty certain mine was the 3M HTD Timing Belt that is 375mm long - the B3M125.

31 minutes ago, Notty said:

not supporting their own 120mm

I was in the same position but then I used the 120MM on my ED80 and can also use it as an all sky camera - no real loss - and to be honest the 120MM being USB3 was a bit of a pain at times and has caused me probelms in the past with limits on cable length. All in the past! In the current grand scheme of things if that is the only infuriating thing then you're very lucky!

31 minutes ago, Notty said:

There literally is no limit to how much money this hobby .....

True!

 

Edited by Adreneline
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I know I've done IC1396 before but this is the best 3 hours of 6 hours of 180s exposures of Ha using the 135mm + ASI1600 (gain 139, offset 50 at -20 degrees) with guiding and dithering. Calibrated and integrated in APP followed by ABE and HistogramStretch in PixInsight and a minimal noise reduction contrast enhancement in Photoshop. I tried using MultiscaleLinearTransform with a mask in PixInsight to reduce noise and all it seemed to do was introduce lots of little black artefacts into the image.

208144758_IC1396-_10800s_2-session_dc_ABE-htlevels.thumb.png.89d1c7d53404cb0ccc4c06e73af29ab4.png

I'm not convinced that this image is that much better than the image I got with no guiding and no dithering!

I'm beginning to think guiding and dithering is not worth the effort with this light weight, wide field setup on my CEM25-EC.

Adrian

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For WO RedCat 51 owners, I just noticed the lens ring can also carry the Samyang 135mm. It's relatively convenient to use, though one disadvantage is that you cannot change the aperture (the collar is too large and covers the aperture ring). But you can set it up before mounting the lens, and probably don't need to change it anyway :) 

The diameter of the ring is 69mm, and 70mm for the lens, which is sufficient to hold the lens securely. It's also super easy to add an accessory (autoguider, focuser) on top of the ring, with the handle or a finder shoe.

image.png.34b0ad562be105392913fca495ac6f2d.png

 

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Posted (edited)
On 03/04/2020 at 17:46, Notty said:

ASIair is an infuriating proposition to me at the moment.  I'd get it today if it supported any old ascom guide camera. I kind of get it that they want to tie you in to their kit, but what I can't forgive them for it not supporting their own 120mm which to me is their affordable guide camera. Unforgiveable!

Alas, the reason behind that is not marketing strategy but bad design years ago! 

It all boils down to the ASI120 USB driver not being 100% compatible with the specs (mainly buffer size, which I assume they forced to decrease overhead and increase frame rate at the time). 

Hence it is not well supported (or at all) by all OS versions , and specifically by INDY on Linux, which is what ASIAIR is built upon, being just a Raspberry PI V3b with INDY and custom software and an Android App

So, they corrected things on the USB3 version, and now just can stick with this one. 

Edited by FaDG
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Also the ASI120 mini version, despite being USB2, is compatible with the ASIAIR. As FaDG said, it seems to be the very first version of the ASI120 that has compatibility issue, which has been resolved in ulterior versions of the camera.

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6 hours ago, Space Oddities said:

Also the ASI120 mini version, despite being USB2, is compatible with the ASIAIR. As FaDG said, it seems to be the very first version of the ASI120 that has compatibility issue, which has been resolved in ulterior versions of the camera.

Thanks, I just noticed this also, subtle difference between 120 and 120 mini, which I hadn't picked up. I forgive them (I'm sure they're very grateful 😜)

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Another Samyang image, this is with the 1100D and Ha filter.

863102016_IC1396Hav11small.thumb.JPG.def576c61208e6771a40b2c62889aef5.JPG

50 minutes of data in total (2 minute subs), took far more but had to ditch a load due to poor tracking.

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Unexpectedly I managed to add some OIII (30 x 180s used - 70 x 180s rejected 😭) to my Ha (60 x 180s) image - I need to try and get another 30 x 180s of OIII to balance things up. It would be nice to add some SII but I don't have a 2" SII filter!

This is pure HOO:

IC1396-HOO.thumb.jpg.9deedcd645528946964abfec6a350f0b.jpg

Thanks for looking.

Adrian

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Hello everyone

 

I finally managed to setup my rig and i would like to hear your inputs about the aberrations i see.

First of all, i have a qhy183m directly attached to a qhycfw3s-sr and an Astro Essentials Samyang to m48 adapter.

I have carefully set up the distance to 44.67mm (taking into account the optical thickness of the filters) and everything seems to be fine mechanically.

I have also made a support ring for the camera, the screws simply touch the camera, i don't want to induce tilt myself by tightening them.

Below there are some pictures of the rig, the focus point and two aberration inspector pics...

 

20200326-104327.jpg

IMG-20200419-120544.jpg

east-stack-mosaic.jpg

west-stack-mosaic.jpg

 

What are your thoughts?

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3 minutes ago, StamosP said:

Hello everyone

 

I finally managed to setup my rig and i would like to hear your inputs about the aberrations i see.

First of all, i have a qhy183m directly attached to a qhycfw3s-sr and an Astro Essentials Samyang to m48 adapter.

I have carefully set up the distance to 44.67mm (taking into account the optical thickness of the filters) and everything seems to be fine mechanically.

I have also made a support ring for the camera, the screws simply touch the camera, i don't want to induce tilt myself by tightening them.

Below there are some pictures of the rig, the focus point and two aberration inspector pics...

 

20200326-104327.jpg

IMG-20200419-120544.jpg

east-stack-mosaic.jpg

west-stack-mosaic.jpg

 

What are your thoughts?

Almost there, as i still can see that kind of coma or whatever you call in few crop frames, but you are almost there as if you take a super wide it won't be shown so clearly until someone zoom in heavily.

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Thanks for your input Tareq

The thing is, the aberrations in the corners are spacing related, tilt or this is a case of decentered optics?

I would appreciate any thought on this...

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Posted (edited)
On 19/04/2020 at 11:03, StamosP said:

IMG-20200419-120544.jpg

I can't help but feel that if this is your infinity focus position then the spacing is incorrect - probably by a fraction of a millmetre. When my stars are in focus the centre mark is right in the middle of the base of the 'L' mark which in my understanding is where it should be. Modern lenses will focus "beyond infinity" so you should not be looking to align the centre mark beyond the 'L' toward the infinity mark either. It took lots of trial and error for me to find the correct spacing and even then inserting/removing a 0.15mm spacer would throw the whole thing out.

Even once I achieved the correct spacing the star shapes in the extreme corners were not perfect compared with the centre of the image; I guess it all comes down to just how good the optics are in your particular lens. Astrophotography makes demands on focussing that are never/rarely required in regular everyday photography.

Good luck.

 

Edited by Adreneline
Clarification
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