why does zwo asi1600mm pro packs come with 2 different filter sizes

[Edward Dewolf]

So I was looking at the asi1600mm pro and noticed it also comes in packs containing a filter wheel and filters.  Bit the filters come in 2 sizes: 31mm or 36mm.  31mm is 1.25".  But what is the 36mm size for?  Why are there 2 options?  is the 1.25" not latching the size of the camera chip?  Will it not generate a full image?  Can anyone explain?  36mm is too small for 2" right?

Can anyone explain why there are 2 sizes and how I would limit myself going for one or the other?
 

Thx!!

 

Edward

[blinky]

I think the 36mm are for things like fast newts - I went for the unmounted filters for use with my F4 newt to avoid vignetting

[Edward Dewolf]

I have a F5 newt, skywatcher 150/750 DPS, .... would that require the 36mm ones?

[Viktiste]

I just ordered a ZWO asi1600mm pro pack with 31mm filters (but with a 80mm refractor). This is what James at FLO said when I asked about the filter size:

 "You can get away with the 1.25" filters if they are mounted very close to the camera - you'd need the camera mounted next to the filterwheel. It's not a problem, but should you want to rearrange things and move the filters to a different part of the system you may find the 1.25" aren't enough. With my Esprit and 1600mm I went for the 31mm set to give me that flexibility in positioning and to make sure there was no chance for vignetting.."

 

Edited September 1, 2019 by Viktiste

[blinky]

12 hours ago, Edward Dewolf said:

I have a F5 newt, skywatcher 150/750 DPS, .... would that require the 36mm ones?

I think it was for f4 and below so you should be fine, I don’t think even at f4 there is too much vignetting.

[jimjam11]

The 1.25 filters are easier to install in the filter wheel but they are not recommended below f5.

31mm filters are noj standard and slightly fiddly to install but they are rated to f2.

36mm is another standard size so I guess it would be usable in other filter wheels/systems...

[Adam J]

On 31/08/2019 at 20:03, Edward Dewolf said:

I have a F5 newt, skywatcher 150/750 DPS, .... would that require the 36mm ones?

No 1.25 inch mounted will do fine for F5

[Adam J]

38 minutes ago, jimjam11 said:

The 1.25 filters are easier to install in the filter wheel but they are not recommended below f5.

31mm filters are noj standard and slightly fiddly to install but they are rated to f2.

36mm is another standard size so I guess it would be usable in other filter wheels/systems...

1.25 inch will work fine down to F4