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Is there consensus on 1.25 filters on the ASI1600 for focal ratios down to F4? (and other questions)

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#1 WonderMellon

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Posted 14 September 2016 - 12:51 PM

I see quite a few people using the ASI1600 camera now and am just about ready to hop on the bandwagon.  So far my experience has been with Canon cameras and I am interested in moving into mono imaging with a cooled camera.  Has there been a consensus on how the 1.25 filters work with or without vignetting?

 

My main scope is that AstroTech imaging Newtonian at F4, but I also have a C9.25 at F10 / F7 and the AT65EDQ at F6.5.  Can anyone confirm if the 1.25 filters will work OK for these setups?

 

 

If the 1.25 filters are OK, is it worth getting the Kit version with the ZWO filter wheel and LRGB filters?  Are the filters of sufficient quality?  I hear a lot of people talking about Baader/Astrodons and I am not sure how these compare.

 

Finally, what is the best way to find out which, and how many, spacers I need?  I use the TOAG for each of the setups above.  I shouldn't need any spacers for the AT65, but the coma correct (Baader Mk III) for the Newtonian and the focal reducer for the Cat will need specific spacing.

 

 

Sorry for all the questions and thanks for any help provided.

 

 

 



#2 telfish

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Posted 14 September 2016 - 01:07 PM

I use the Baader 1.25 filters with my APO. They have a wider cutoff in UV which helps control star bloat in the blue channel when using a refractor. At F7.5 just a little vignetting.

 

Have not used them yet with my Newt at F3.9.



#3 Gucky

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Posted 14 September 2016 - 01:49 PM

I bought 36 mm filters, wildcatting the next ASI might be about APS-C size and I could still use them.



#4 Ladyhawke

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Posted 14 September 2016 - 01:50 PM

I use Astrodon LRGB and Narrowband and have also used Optolong LRGB with great sucess on my ASI 1600 mono



#5 WonderMellon

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Posted 14 September 2016 - 02:07 PM

Telfish,  Vignetting at F7.5?  I thought there was supposed to be no vignetting down to F5 and possibly good at F4.

 

Peter, Are you using the ZWO electronic filter wheel and the 36mm fit?  If not, which filter wheel are you using?

 

Sam, what filter wheel are you using? 

 

 

It looks like the XAGYL ($250) at 19mm and the ZWO ($199) at 20mm are the thinnest 1.25 filter wheels.



#6 noisy

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Posted 14 September 2016 - 02:35 PM

I get vignetting on my asi1600 at f/6.25, the ZWO mini-EFW and 1.25" filters. It's not much though (didn't measure it, but it wasn't obvious in images, only flats). I've been meaning to try it with the EOS adapter and a much faster lens but haven't yet.



#7 Jon Rista

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Posted 14 September 2016 - 02:51 PM

I have not experienced any real issues with vignetting with 1.25" filters at f/4:

 

Ia7C03j.jpg

 

However, I should note that I carefully constructed my imaging train to get the filters as close as possible to the sensor. I used a custom PreciseParts adapter to connect my filter wheel directly to the camera, which allowed me to get the filters less than 14mm from the sensor. If I had not done that, I would have had an extra 11mm of extension in there, putting the filters almost 24mm from the sensor. This distance from filter to sensor matters, and will affect how much you vignette. There is actually a formula that allows you to calculate the right distance...I don't have it handy at the moment. 

 

Anyway, if you want to use the smaller filters, just make sure you get the filter as close to the sensor as possible. PreciseParts adapters, and a thinner FW (the SX is 29mm thick, the Atik EFW2 is 22mm thick, the ZWO miniEFW is 20mm thick, and the Xagyl are 19mm thick), will get your filters close enough to not be a problem, even if you use 1.25" ones.



#8 Dan Finnerty

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Posted 14 September 2016 - 03:20 PM

Page 16 of the ASI 1600 manual states "Here are the steps to show you how to connect mono 1600 and our EFWmini to your scopes. Benefiting from the short back focus design, 1.25” filter can support up to F5 scope without vignetting and 31mm filter can support up to F2 scope without vignetting."

 

I went for a set of Optolong 31mm RLGB filters. Just installed them last night.



#9 Gucky

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Posted 14 September 2016 - 03:29 PM

I'm using the starlight express usb filter wheel with 7 astronomik filters. 



#10 WonderMellon

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Posted 14 September 2016 - 05:29 PM

Thanks everyone, there is some good stuff here


Jon, how do I order the precise parts adapter? I don't see a way to get it on their calculator

#11 telfish

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Posted 14 September 2016 - 05:50 PM

Telfish,  Vignetting at F7.5?  I thought there was supposed to be no vignetting down to F5 and possibly good at F4.

 

Peter, Are you using the ZWO electronic filter wheel and the 36mm fit?  If not, which filter wheel are you using?

 

Sam, what filter wheel are you using? 

 

 

It looks like the XAGYL ($250) at 19mm and the ZWO ($199) at 20mm are the thinnest 1.25 filter wheels.

It's very slight. I am waiting on a new adapter that can get my filter wheel a fair bit closer to the camera.



#12 Jon Rista

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Posted 14 September 2016 - 06:08 PM

Thanks everyone, there is some good stuff here


Jon, how do I order the precise parts adapter? I don't see a way to get it on their calculator

What filter wheel do you have?



#13 Ladyhawke

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Posted 14 September 2016 - 06:41 PM

I use an Atik filter wheel, with f/4.9 WO Star 71 no vignetting. All my filters are 1.25"

Telfish,  Vignetting at F7.5?  I thought there was supposed to be no vignetting down to F5 and possibly good at F4.

 

Peter, Are you using the ZWO electronic filter wheel and the 36mm fit?  If not, which filter wheel are you using?

 

Sam, what filter wheel are you using? 

 

 

It looks like the XAGYL ($250) at 19mm and the ZWO ($199) at 20mm are the thinnest 1.25 filter wheels.



#14 NyxAither

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Posted 14 September 2016 - 06:47 PM

Here's my flat from my f/3.94 with the new ZWO 1.25 filters and their new EFW. You can see that it really isn't bad, and if I could get my optics straightened out it would be even better (only a ~10% loss at the corners, certainly less than 15%)!
 
Flat0990ms.JPG

Edited by NyxAither, 14 September 2016 - 06:48 PM.


#15 NyxAither

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Posted 14 September 2016 - 06:50 PM

Thanks everyone, there is some good stuff here


Jon, how do I order the precise parts adapter? I don't see a way to get it on their calculator

 

If you're getting the ZWO EFW then you don't need any adapters. The wheel and camera screw directly together, putting the filter ~10 mm from the sensor according to ZWO.


Edited by NyxAither, 14 September 2016 - 06:51 PM.


#16 dkeller_nc

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Posted 14 September 2016 - 06:57 PM

I use the ZWO ASI1600M camera with an Atik EFW2 wheel and 1.25" filters.  I currently use the adapter that ZWO ships with the camera, which is essentially an all-thread ring that allow connecting the M42 threads on the ZWO camera body to the M42 male thread on the the Atik wheel.  There is definitely vignetting with the set-up, most noticeably on the 4 corners of the frame.  Probably removable with flats, but I haven't bothered with calibration frames yet.

 

It's possible to remove the ring, reverse the filter wheel and screw the ZWO camera directly to it, though in my case that then requires an adapter for the Atik that will allow me to screw the field flattener into the filter wheel.  Atik does make several adapters for the EFW2 that allows a lot of different combinations, I just haven't ordered them yet.



#17 WonderMellon

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Posted 14 September 2016 - 08:52 PM

Ok, you guys have me just about ready to pull the trigger on the 1600, EFW and Filter set kit.  It looks like I will not need a special adapter for the filter wheel and the 1.25" filters should work with minimal vignetting at F4. 

 

It looks like you only save about $50 (3%) by getting the bundle.  Are the ZWO filters acceptable, or should I get an upgraded brand?  I'll admit I like the $148 of the ZWO LRGB filter set versus $379 for the Baader, 299 for IDAS and $475 for Astrodon; but if the upgrade saves a whole lot of headache, it may be worth it. 

 

I have the Telescop Express TOAG currently.  It connects directly to the Canon and then has 2 inch threads on the other side.  Will I need a different adapter for using it with the ASI?

 

Thanks for all the help so far, I appreciate all the information.



#18 telfish

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Posted 14 September 2016 - 09:10 PM

Is your Refractor a triplet? If yes then the zwo filters should be ok. If it's a doublet you could have issues with bloated stars in the blue and to a lesser extent the Luminance channels. Best reasonable alternative are the Baaders, if you are feeling flush then the Astrodon's



#19 WonderMellon

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Posted 14 September 2016 - 09:19 PM

The refractor is actually a quad; then there is the imaging newt (my main scope) and the C9.25 SCT.



#20 Jon Rista

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Posted 14 September 2016 - 09:20 PM

Ok, you guys have me just about ready to pull the trigger on the 1600, EFW and Filter set kit.  It looks like I will not need a special adapter for the filter wheel and the 1.25" filters should work with minimal vignetting at F4. 
 
It looks like you only save about $50 (3%) by getting the bundle.  Are the ZWO filters acceptable, or should I get an upgraded brand?  I'll admit I like the $148 of the ZWO LRGB filter set versus $379 for the Baader, 299 for IDAS and $475 for Astrodon; but if the upgrade saves a whole lot of headache, it may be worth it. 
 
I have the Telescop Express TOAG currently.  It connects directly to the Canon and then has 2 inch threads on the other side.  Will I need a different adapter for using it with the ASI?
 
Thanks for all the help so far, I appreciate all the information.


Are you getting the ZWO filter wheel? IF so, then you do NOT need an adapter. The miniEFW screws onto the ASI1600 at it's minimum backfocus by default.

#21 WonderMellon

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Posted 14 September 2016 - 09:31 PM

Jon,

  Unless an issue jumps to the forefront, I am planning on getting  the ASI1600MM-C, ZWO EFW and ZWO filter bundle. 

 

It sounds like that will give me a well illuminated field, Cooled mono performance and few, if any, filter issues.  It sounds like the only thing missing is the H-Alpha, but ZWO has mentioned they plan to roll that filter out in October.

 

It sill need to work out spacer distances and a connection from the ZWO EFW to the TS TOAG.  I am hoping that if I take out the EOS adapter, the filter wheel will screw directly into the OAG, but I doubt it is that easy.



#22 rockstarbill

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Posted 14 September 2016 - 09:31 PM

Ok, you guys have me just about ready to pull the trigger on the 1600, EFW and Filter set kit. It looks like I will not need a special adapter for the filter wheel and the 1.25" filters should work with minimal vignetting at F4.

It looks like you only save about $50 (3%) by getting the bundle. Are the ZWO filters acceptable, or should I get an upgraded brand? I'll admit I like the $148 of the ZWO LRGB filter set versus $379 for the Baader, 299 for IDAS and $475 for Astrodon; but if the upgrade saves a whole lot of headache, it may be worth it.

I have the Telescop Express TOAG currently. It connects directly to the Canon and then has 2 inch threads on the other side. Will I need a different adapter for using it with the ASI?

Thanks for all the help so far, I appreciate all the information.

Are you getting the ZWO filter wheel? IF so, then you do NOT need an adapter. The miniEFW screws onto the ASI1600 at it's minimum backfocus by default.

Once you remove the black adapter that comes threaded on.

#23 TimN

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Posted 14 September 2016 - 09:38 PM

I have the XAGYL filter wheel and you don't need an adapter with that one either. The 11mm adapter that comes with the camera unscrews allowing the camera to screw directly into the filter wheel.

 

I can't comment on the ZWO filters as I got Baaders. I've only taken 3 images and although they seem OK, I would feel better recommending them if I had more use. I haven't had a problem with vignetting but at f7.5 that's not a surprise.



#24 Jon Rista

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Posted 14 September 2016 - 11:17 PM

Jon,
  Unless an issue jumps to the forefront, I am planning on getting  the ASI1600MM-C, ZWO EFW and ZWO filter bundle. 
 
It sounds like that will give me a well illuminated field, Cooled mono performance and few, if any, filter issues.  It sounds like the only thing missing is the H-Alpha, but ZWO has mentioned they plan to roll that filter out in October.
 
It sill need to work out spacer distances and a connection from the ZWO EFW to the TS TOAG.  I am hoping that if I take out the EOS adapter, the filter wheel will screw directly into the OAG, but I doubt it is that easy.


I don't think you will have any issue with vignetting. ZWO designed their own FW to get the filters down to 10mm from the sensor. That is better than I can do even with a zero-backfocus adapter (which I've ordered from PP). I think the closest I can get is ~13mm.

I would not worry about vignetting at all for f/4 or slower if you get the ZWO kit.

#25 WonderMellon

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Posted 15 September 2016 - 07:29 AM

Ok, sounds like the ZWO camera and Filter wheel are the way to go.  I will probably get the kit with their filters as well.

 

Does anyone know if I need to get a different adapter for the TS TOAG?  My camera side has an EOS adapter on it now, but it appears that the OAG itself is threaded if I remove the adapter.  I haven't taken it apart to play with it yet.

 

Also, any recommendation on spacers for the Baader Mk III coma corrector as well as SCT T-Ring replacement?  I plan to call OPT this afternoon.  They have been helpful in spacer calculations in the past, but if someone here knows the correct ones, I can check the math.

 

Thanks again for all the help.




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