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ASI1600 + Samyang 135mm Imaging configuration detail


bdlbug

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I have been asked by a few forum members to detail how I built my imaging rig based around the Samyang 135mm f2 lens and ASI1600MM CMOS camera.
A number of people asked within the topics /images I posted last year of M31, Andromeda and Orions Belt / Sword and the topic recently reappeared thanks @StarManFlorida

 

For the specific imaging configuration that I used for these images and the components used are

  • ZWO ASI1600MC
  • ZWO Mini 5 position EFW fitted with Baader 1.25" LRGB+Ha(7nm) filters
  • ZWO EOS-T2 Lens adapter
  • ZWO Camera holder
  • ADM _losmandy_dovetail-2ADM Losmandy-type Universal Dovetail bars :7" imperial
  • ADM_Guidescope_Finderscope_Rings_100mmADM Guide scope Rings including the mounting block to equalize height of camera mounting

The component you might think looks like a dual ring saddle up front on the lens is a Microfocuser, as explained below, getting accurate fine focus by manually twisting the lens is impossible - possibly a better solution some other people have built is to use a belt drive with a ASCOM controlled focusing motor - but a delicate touch and very good focus can be achieved with this mechanism. If you want to investigate the motorised option then you can probably google 'widefield rigs' and see some good examples.
It does take a little bit of figuring out the best way to clamp the device onto the lens, and also, it will not fit from the front of the lens so remember to fit it at least onto the lens before yoy connect the lens to the EOS-T2 adapter - I of course worked this out the hard way.

The TeleFokus was created to solve an everyday problem of astro imaging. Focusing astro images precisely can be extremely difficult. The focusing mechanism of standard camera lenses is not really up to the task. A very fine movement of the focusing mechanism already changes focus by a larger amount than desired. Even if perfect focus is found it is often lost again because the focus cannot be locked. The TeleFocus can be fitted on most standard lenses and provides both a very fine focusing movement and also a focus lock.https://www.teleskop-express.de/shop/product_info.php/info/p3285_Microfocuser-and-focus-lock-fuer-camera-lenses-up-to-D-80mm.html

The ZWO components , within the red bar on image below, all fit together very well and result in the correct 44mm backfocus required by the camera lens - one point to note is that you have to remove the T2 extender that is factory fitted (at least it was on the camera when I bought it new) and screw the mini EFW directly onto the camera body, otherwise the backfocus will be wrong  once you fit the EOS-T2 adapter  on the opposite side of the EFW.

Additional Information
The camera requires an additional 12v power feed so the cooler operates effectively, that is the thick orange cable in image below - I use a 'lab' power supply as I have a fixed obsy with power feed, it can of course be supplied by a battery based PSU.
The link back to the laptop is via a 3m USB 3 cable
The ASI1600 has an integrated USB hub so I used the short link cable supplied with the EFW to link the EFW into the laptop USB network
Software
All controlled via ASCOM
APT used to control camera and drive imaging sessions
 Cartes du Ciel used to drive goto functionality of the software

I operate the camera at a set point temperature of -20degC


Hope this information helps you build your own rig

image.png.781baa1300bbfdcd760a3b6e5c756789.png

 

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Good explanation of this setup.

If anyone wants to add a motor focuser a simple way is with a SW motor, a timing belt and the smallest diameter toothed pulley available.
Make a simple bracket/plate that allows some tensioning and focusing is easy with either just the hand controller or via USB if needed.

In my setup I just use the hand controller.
The belt will tend to lock the focus with just the odd focus tweak at every session, getting an fwhm of 2 or under is  fairly easy.
Here is my lash-up. ?

atiksamyang2.jpg.9b5cb231136144bef000ce0e303e2489.jpg

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HI BDL...

Referring to your picture showing the ADM products.  I went to the ADM website and I believe that you are showing the ADM - VDUP7-V Series Universal Dovetail Bar. 7" long AND the VR100-V series docetail ring set. 100mm adjustable rings.   Would you please confirm this ?

 

Thank you...  Frank

 

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12 hours ago, wxsatuser said:

If anyone wants to add a motor focuser a simple way is with a SW motor, a timing belt and the smallest diameter toothed pulley available.
Make a simple bracket/plate that allows some tensioning and focusing is easy with either just the hand controller or via USB if needed.

I really like your solution using the SW motor. I use two on my ED80 and ZS71 with 3D printed mounts to attach them to the focussing unit.

I've gone for the manual assist approach with my Samyang 135mm and 85mm.

These units might not be as polished as the TS ones but they are half the price and although a little fiddly to setup initially they seem to do the business. I also find it quite easy to obtain FWHM readings below 2 on both the 135 and the 85. Search AstroKraken on the web to get the details of these and various other 3D printed accessories. As an aside customer service from Philippe is second to none!

Wide field setup:

IMG_8180.thumb.jpg.278c8349dba36aecf2e08f9cea0d2e00.jpg

85mm

IMG_8177.thumb.JPG.44d527a52690714c5b1fb1cd3eb30b0c.JPG

135mm

IMG_8178.thumb.jpg.8a6cba0a31643a07e64839a2178c65b6.jpg

The second Vixen bar allows me to mount the guide scope directly to the Samyang 185mm for those occasions when I want to use the 185mm alongside either the SW-ED80DS or the WO-ZS71.

Hope this is of interest.

Adrian

 

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2 hours ago, StarManFlorida said:

HI BDL...

Referring to your picture showing the ADM products.  I went to the ADM website and I believe that you are showing the ADM - VDUP7-V Series Universal Dovetail Bar. 7" long AND the VR100-V series docetail ring set. 100mm adjustable rings.   Would you please confirm this ? 

 

Thank you...  Frank

 

I bought the components from UK supplier and sponsor of this site, First Light Optics, FLO - these are the parts on their website and the part numbers are slightly different from your description as in they dont have 'V' but they are R-100, DUP7

https://www.firstlightoptics.com/adm-guide-rings/adm-guidescope-rings.html

image.png.5ceb6e59abc20d2dc3d357c956b284fc.png

https://www.firstlightoptics.com/dovetails-saddles-clamps/adm-losmandy-style-universal-dovetail-bars.html

image.png.2f004f7cb5eafdf80e3fb243282af956.png

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  • 1 month later...

This looks great. Currently I am using a Canon DSLR and Canon 400 5.6 L with my NEQ6 mount.

Either going to go with  a Scope (SW Esprit 100) or an ASI 1600MM Pro and filter wheel.

Cannot do both together.

Can anyone see any problems with using the ASI with the Canon 400mm and filter wheel? Focus, Field Flatness etc?

 

Thanks for any info :)

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  • 4 weeks later...

Hi guys, I have been looking for a secondhand Samyang135mm for the last 3 months and was not able to find any! :)

What their usual prices for a used ones?

I have found a boxing day deal for £320 new ... not sure if I should wait longer!!! :)

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