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EFW installation to ASI2600mm and scope

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#1 Distant

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Posted 18 May 2024 - 10:22 PM

This is my first setup and all the different thread types are still somewhat new to me, so please excuse the basic questions.

 

I have gotten a new 36mm x7 EFW from ZWO and struggling with proper installation to my ASI2600mm and Askar FRA400 scope.
This older thread is discussing at least the EFW-to-camera side, but it is not covering all my questions.

 

For starters, I assume these 2 methods are still up to date:

diagram2.jpg

 

 

Tried to follow method 1 first but it is not 100% identical, as demonstrated in the following setup:

installation1.jpg

 

Instead of the T2-M48 16.5mm as shown in the diagram, I am using an M42-M48 16.5mm adapter. This threads directly into the scope's conical M48 adapter. It all fits together but I wonder if this is correct?

 

 

Also, as by the aforementioned thread, it seems the recommended way would be method 2 (closer distance between filters and sensor, less risk of light leak and adapters coming loose …). In that case I would need to purchase an extra M42M-M48F 22.5mm extender but it seems to be worth it. However, I am wondering how to bolt the EFW to the camera directly after removing the tilt plate. On YouTube there are 2 methods, one is to leave one filter place open and perform the screwing through the empty filter space. The other method suggests to remove the whole filter carousel as this would be easier - but I also read other comments warning to remove the carousel.



#2 Dynan

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Posted 18 May 2024 - 10:54 PM

I removed the carousel and the installation went fine. The EFW works perfectly after a calibration.

 

EDIT: And you are correct in removing the useless tilt plate.


Edited by Dynan, 18 May 2024 - 10:56 PM.

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#3 idclimber

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Posted 18 May 2024 - 11:10 PM

The method you want to use is the one on the right. You remove the tilt plate and bolt the filter wheel directly to the camera. 


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#4 Distant

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Posted 18 May 2024 - 11:48 PM

Thanks for the quick feedback! Alright, I will definitely go for the method on the right.

 

Two more questions though:

 

1)

The 22.5 mm M42M-M48F adapter I'd need to connect EFW to scope is apparently not sold in my country. It will probably take a few weeks if ordering from abroad. In the meantime, could I use the adapters that came with my ASI2600mm?

adapters2.jpg

This adds up to more than 22.5mm obviously, but the scope I am using is a petzval design so my understanding is backfocus should not be an issue?

 

2)

In the ZWO forum a user posted that once he went with removing the tilt plate and bolted the EFW to the camera directly, he introduced light leakage. Apparently, newer EFW come with dark rings which I got as well. How would I align them properly to reduce the risk of light leakage? If screws are not being used (e.g. EFW-scope side), I guess it would make sense to turn them so they are covering the screw holes.



#5 Dynan

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Posted 19 May 2024 - 07:01 AM

I didn't use the fiber ring. I have no light leaks. YMMV.


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#6 idclimber

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Posted 19 May 2024 - 09:28 AM

Backspace is determined by the scope or reducer. You should be fine at that spacing. 


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#7 Distant

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Posted 01 June 2024 - 03:15 AM

Backspace is determined by the scope or reducer. You should be fine at that spacing. 

I was not fine using the 16.5 + 21 adapters. Then removed the 21 and only used the 16.5. This worked well. The FRA400 has a focus spacing scale of 1-5, and with the 16.5 adapter I was right at 2.6 on the scale, so pretty much in the middle.

 

Now, the 22.5 which I had ordered has been delivered and I am unsure if it is still needed. The 16.5 was supposed to be a temporary solution, to be replaced with the 22.5 just as by the official diagram of ZWO as shown in the opening post.

 

Here is a comparison of the 16.5 vs. the newly acquired 22.5

temp3.jpg

 

This is how it looks like now with the 16.5 attached right to the EFW:

temp2.jpg

 

Since the scope is Petzval design, I assume as long as I reach focus (which I do with the current setup), it should be fine - and I would like to keep it as it is, since the whole image train is a bit shorter now which has several advantages. Or am I missing something here and it would be better to follow the official solution, using the longer 22.5 adapter?




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