Filter size for imaging camera

[TareqPhoto]

Hi,

If i get one of those mono camera for imaging, and using a filter wheel, what size of filters should i get?

Does the size of filter depends on the wheel or the scope or the camera?

I am not sure which wheel i may get, but i will go with one that can take many filters at once [7 or 8 filters wheel]?

[steppenwolf]

This depends on the camera and the position of the filter wheel. We need more information, please - what mono camera are you considering?

[Scott]

what he said 

[TareqPhoto]

I am not sure but for now it is like 95% it will be ASI1600mm mono cooled one, not sure if i will go with QHY or something else, but i will try to kep my decision on ASI1600 mono.

 

[DaveS]

In that case if you go with the ZWO wheels then you can use 1.25" filters which are the cheapest.

I think they do 5 and 8 position (I know they do a 5-wheel as I have one myself).

Edit:

Here you are

https://www.firstlightoptics.com/filter-wheels/zwo-electronic-filter-wheel-efw-8-x-125-or-7-x-36mm.html

[TareqPhoto]

I was asking my question but wasn't clear, i was asking which filter to choose, 1.25" or 31mm or 36mm?

From another site it is about the scope i will use and not about which camera or which wheel, so i want to be sure what i am into.

[Scott]

You will also be needing a flattener. that's a big chip. I have no experience with this camera/filter wheel so will bow to the experience of others but I would have thought 2" filters might be needed. what scope are you using?

[TareqPhoto]

Now no scope for it, but in my future plan soon there is maybe Esprit ED80mm F/5, also maybe one of those PDS scopes [could be 130 or 200], but for now i can reply on my ST80 or my Canon lenses temporary, but that time if i buy ASI1600 i think i will be getting another scope, but i won't look for less than F5-F6 scopes.

[DaveS]

OK

The FLO site says that you can use a 'scope down to f/5 with no vignetting with 1.25" filters, and down to 3.something with 31mm. Even with the 1.25" I've used them down to f/4.4 with minimal vignetting that flats will correct anyway.

@Ginahas used them down to f/2.5 (If I remember correctly) with only slight vignetting which can be corrected with flats.

By all means buy 31mm, they're often the same price or only a little more than 1.25", but hey're a lot more fiddlyely to mount.

[TareqPhoto]

1 minute ago, DaveS said:

OK

The FLO site says that you can use a 'scope down to f/5 with no vignetting with 1.25" filters, and down to 3.something with 31mm. Even with the 1.25" I've used them down to f/4.4 with minimal vignetting that flats will correct anyway.

@Ginahas used them down to f/2.5 (If I remember correctly) with only slight vignetting which can be corrected with flats.

By all means buy 31mm, they're often the same price or only a little more than 1.25", but hey're a lot more fiddlyely to mount.

Great, this is what i was looking for, i thought if i will use F5 and faster then i must use 36mm only, but i asked also if i will use subs such as flat and bias but no reply to me, so only slight vignetting is the problem that can be corrected either by subs or processing or whatever, then i will save by going with 1.25" or 31mm, thank you very much!

[TareqPhoto]

Someone replied to me as i asked if vignetting is the only issue i will see with smaller filter, this is his reply:

"only"? Vignetting is an issue, and no, you can't fully solve it by process. Bias compensates for shutter noise. Flats do reduce vignetting, and of course you can always crop. But you won't be taking full advantage of your equipment. 

If you want to be as prepared for "anything" with the ASI1600MM-Cool, then get the EFW7 with 36mm filters. It only costs you $200 over the 1.25" mounted and only $100 over the 31mm unmounted. "

[Gina]

Maybe but 36mm NB filters are very much more expensive than 1.25" ones!!  This is where the main cost is.  If cost is irrelevant then get the very best, otherwise 1.25" filters are fine.  Only rarely will what you are imaging reach out as far as the corners of your sensor frame - DSOs look best with a certain amount of clear starfield around them.

[iapa]

12 hours ago, Scott said:

You will also be needing a flattener. that's a big chip. I have no experience with this camera/filter wheel so will bow to the experience of others but I would have thought 2" filters might be needed. what scope are you using?

If I have this right, and I hope so as this is what I bought

Back focus (distance between the glass and the camera sensor) for both the Skywatcher Field Flattener (for f6-f7 refractors) and  Skywatcher 0.9x Coma Corrector (for f4-f5 newtonian) is 55mm.

Both of these have M48 thread at the camera side, so you will need an M48 female to M42 male adapter to attach either to the filter wheel.

With the ASI1600 connected to the EFW minifilter wheel you have 26.5mm back focus, 6.5mm for the camera and 20mm for the filter wheel.

FLO sell M48 to M42 adapter FLO M48 to T2 adapter which adds 10mm to back focus, I haven't been able to find anything to fit the remaining 18.5mm

365Astronomy sell Adapter from M48 (2-inch filter thread) to T2 - Low Profile which has 3.5mm back focus which I bought and use with Baader VariLock 29 Lockable T-2 Extension Tube

so,

• ASI1600MM-C 6.5mm
• ZWO EFW mini 20mm
• M48-M42 adapter 3.5mm
• variable extension tube 20-29mm

will give you 50-59mm of back focus. Being adjustable if yo spend the time you can get it exactly right for you kit

 

 

[iapa]

12 hours ago, TareqPhoto said:

I am not sure but for now it is like 95% it will be ASI1600mm mono cooled one, not sure if i will go with QHY or something else, but i will try to kep my decision on ASI1600 mono.

 

FLO sell bundles with camera, filters and wheel

 

https://www.firstlightoptics.com/zwo-cameras.html

I made a big mistake and bought the mini bundle with LRGB. I should have spent that extra few pounds to get the LRGBHa set. <sigh>

Still, I was always intending to have two cameras and filter wheels...... where has SWMBO hidden that cheque book...

[TareqPhoto]

5 hours ago, Gina said:

Maybe but 36mm NB filters are very much more expensive than 1.25" ones!!  This is where the main cost is.  If cost is irrelevant then get the very best, otherwise 1.25" filters are fine.  Only rarely will what you are imaging reach out as far as the corners of your sensor frame - DSOs look best with a certain amount of clear starfield around them.

Yes i know it is very very expensive that is why i asked so i don't want to spend out then figuring out it wasn't necessary, 1.25" is already expensive but i must go with something, but that 36mm is really too too much, but i have to know when i should get 1.25" or when i should get 36mm instead so i don't end up wasting money on wrong size.

[TareqPhoto]

4 hours ago, iapa said:

If I have this right, and I hope so as this is what I bought

Back focus (distance between the glass and the camera sensor) for both the Skywatcher Field Flattener (for f6-f7 refractors) and  Skywatcher 0.9x Coma Corrector (for f4-f5 newtonian) is 55mm.

Both of these have M48 thread at the camera side, so you will need an M48 female to M42 male adapter to attach either to the filter wheel.

With the ASI1600 connected to the EFW minifilter wheel you have 26.5mm back focus, 6.5mm for the camera and 20mm for the filter wheel.

FLO sell M48 to M42 adapter FLO M48 to T2 adapter which adds 10mm to back focus, I haven't been able to find anything to fit the remaining 18.5mm

365Astronomy sell Adapter from M48 (2-inch filter thread) to T2 - Low Profile which has 3.5mm back focus which I bought and use with Baader VariLock 29 Lockable T-2 Extension Tube

so,

• ASI1600MM-C 6.5mm
• ZWO EFW mini 20mm
• M48-M42 adapter 3.5mm
• variable extension tube 20-29mm

will give you 50-59mm of back focus. Being adjustable if yo spend the time you can get it exactly right for you kit

 

 

So what are you trying to say? if i bought those adapters and tubes then i can use smaller size filters of 1.25"?

[TareqPhoto]

4 hours ago, iapa said:

FLO sell bundles with camera, filters and wheel

 

https://www.firstlightoptics.com/zwo-cameras.html

I made a big mistake and bought the mini bundle with LRGB. I should have spent that extra few pounds to get the LRGBHa set. <sigh>

Still, I was always intending to have two cameras and filter wheels...... where has SWMBO hidden that cheque book...

I like the bundle except the filters included, if the bundle including only the camera and that 8 filters wheel then i am sold, but i really don't want to buy those filters from ZWO, unless the filters are very cheap and the price isn't much so then i may get it and buy another filters as replacement without losing much, i found another site to order the camera and filter cheaper than FLO.

[Adam J]

ASI1600mmc is ok with 1.25 mounted so long as you get the ZWO filter wheel. Now as for the QHY163m I have seen evidence that 1.25 inch filters will work but also that they are more marginal than with the ASI as the camera has ever so slightly more back focus. 

[iapa]

1 hour ago, TareqPhoto said:

I like the bundle except the filters included, if the bundle including only the camera and that 8 filters wheel then i am sold, but i really don't want to buy those filters from ZWO, unless the filters are very cheap and the price isn't much so then i may get it and buy another filters as replacement without losing much, i found another site to order the camera and filter cheaper than FLO.

The filters in the bundles are manufactured specifically for the ASI1600 camera with their filter wheels.

TBH not sure what is different, may be thickness, but if they are made specific to the camera/efw then, personally, I'd not look at others.

[TareqPhoto]

2 hours ago, iapa said:

The filters in the bundles are manufactured specifically for the ASI1600 camera with their filter wheels.

TBH not sure what is different, may be thickness, but if they are made specific to the camera/efw then, personally, I'd not look at others.

Maybe, but Astrodon are filters to look at, it is like they are the Swiss knife of filters, so i won't look for anything less, and those LRGB price isn't very expensive, $475 for 1.25" and $525 for 31mm ones, i know this sounds so expensive, but i can tell it is like i buy 4 filters at once, so each is slightly over $100, not a bad price for LRGB together, so i can go with that one, but the more expensive filters are the Ha/OIII/SII each alone, the cheapest is $330 for Astrodon, so i am not worry about LRGB and i prefer it from Astrodon, but i don't want to buy the bundle if i will buy filters else where, and i know almost all those filters from different brands will do the job just fine, but i look at the best brand of the filters which is Astrodon from what i read.

The price is almost high even if i choose from ZWO or Baader or whatever brand, all those filters are almost like $100-500 for one filter according to the size, the camera and the wheel price are known and the option is fixed, but filters is vary by sizes, so i can't tell or decide if i want the smallest one or the largest one, if you tell me i should go with 1.25" and i will be fine without much issue then i will be happy and go with that, but if the issue is very bad or can't be solved then i better not waste money on wrong ones then, it will be like i pay less and have issues later to deal with, then i may pay again to eliminate those issues by other tools, for now 1.25" and 31mm are more affordable regardless expensive, but 36mm is really too much, and i really don't know if i just want to have luxury items so that i want Astrodon, i am sure another brands will do good job, but i feel jealous when others using either expensive mount or expensive scope or even expensive filters, by those i only can afford expensive filters.

[SonnyE]

On 6/1/2017 at 10:00, TareqPhoto said:

Maybe, but Astrodon are filters to look at, it is like they are the Swiss knife of filters, so i won't look for anything less, and those LRGB price isn't very expensive, $475 for 1.25" and $525 for 31mm ones, i know this sounds so expensive, but i can tell it is like i buy 4 filters at once, so each is slightly over $100, not a bad price for LRGB together, so i can go with that one, but the more expensive filters are the Ha/OIII/SII each alone, the cheapest is $330 for Astrodon, so i am not worry about LRGB and i prefer it from Astrodon, but i don't want to buy the bundle if i will buy filters else where, and i know almost all those filters from different brands will do the job just fine, but i look at the best brand of the filters which is Astrodon from what i read.

The price is almost high even if i choose from ZWO or Baader or whatever brand, all those filters are almost like $100-500 for one filter according to the size, the camera and the wheel price are known and the option is fixed, but filters is vary by sizes, so i can't tell or decide if i want the smallest one or the largest one, if you tell me i should go with 1.25" and i will be fine without much issue then i will be happy and go with that, but if the issue is very bad or can't be solved then i better not waste money on wrong ones then, it will be like i pay less and have issues later to deal with, then i may pay again to eliminate those issues by other tools, for now 1.25" and 31mm are more affordable regardless expensive, but 36mm is really too much, and i really don't know if i just want to have luxury items so that i want Astrodon, i am sure another brands will do good job, but i feel jealous when others using either expensive mount or expensive scope or even expensive filters, by those i only can afford expensive filters.

If cost is not an object, then I would get the bigger filters.

My reason is I can remove my DSO camera, and screw on my DSLR. But while the DSO camera works fine with my 1.25" filters, my DSLR gets horrible Vignetting, and coma through the smaller filters. (Sensor size differences)

Too large a filter can 'future proof' your choices now. Where too small a filter choice now, might not work well in the future if a different (larger) sensor should be chosen. Make sense?

I refer to that as my 'Buy once, cry once' Philosophy. As opposed to a buy wrong, cry all night long mistake.

The bottom line is, you have to please yourself, as you will be living with your choices.

[spillage]

I see that if you replace the 1.25 filters lrgb and haos with baader one this will on be an extra £100. How do the baader ones fair compared to the zwo ones.

[TareqPhoto]

I think i am going with 31mm at the end, i gonna buy a mono camera so it will be fine with smaller sizes filters, i don't see myself going with DSLR for my DSO imaging, and if i will use a DSLR then i simple buy a cheaper brands larger size, it is not worthy i use Astrodon with DSLR anyway so i must buy larger, a mono camera it will be my main imaging camera, later when i modify my DSLR then i can think about larger filters cheaper options.

[SonnyE]

12 hours ago, TareqPhoto said:

I think i am going with 31mm at the end, i gonna buy a mono camera so it will be fine with smaller sizes filters, i don't see myself going with DSLR for my DSO imaging, and if i will use a DSLR then i simple buy a cheaper brands larger size, it is not worthy i use Astrodon with DSLR anyway so i must buy larger, a mono camera it will be my main imaging camera, later when i modify my DSLR then i can think about larger filters cheaper options.

Makes sense. Have fun.

It is very rare indeed I change cameras. Just wanted to point out about the pinch effect.

[ollypenrice]

On 16/06/2017 at 07:42, SonnyE said:

If cost is not an object, then I would get the bigger filters.

My reason is I can remove my DSO camera, and screw on my DSLR. But while the DSO camera works fine with my 1.25" filters, my DSLR gets horrible Vignetting, and coma through the smaller filters. (Sensor size differences)

Too large a filter can 'future proof' your choices now. Where too small a filter choice now, might not work well in the future if a different (larger) sensor should be chosen. Make sense?

I refer to that as my 'Buy once, cry once' Philosophy. As opposed to a buy wrong, cry all night long mistake.

The bottom line is, you have to please yourself, as you will be living with your choices.

The coma you are seeing is not from the filters but the optics. Clearly your scope, as it stands, is not delivering a flat enough field for your DSLR chip and having bigger filters wouldn't change that.

How horrible is your vignetting? We get a fall off in one of our rigs from 23000 ADU in the centre to about 18,500 ADU in the corners. That's a lot, but flats correct it.

Filter size also has a bearing on how many filters will fit in your wheel.

On 31/05/2017 at 23:18, TareqPhoto said:

Great, this is what i was looking for, i thought if i will use F5 and faster then i must use 36mm only, but i asked also if i will use subs such as flat and bias but no reply to me, so only slight vignetting is the problem that can be corrected either by subs or processing or whatever, then i will save by going with 1.25" or 31mm, thank you very much!

You will always need flats. They are very important. If you intend to use flats then you will also need a master bias to use as a dark for your flats. Since shooting a set of bias is so easy you might as well do it. I would use my master bias as a dark for my flats and also as a dark for my lights. I don't find full length darks very helpful on low noise chips but not having tried this camera I can't predict how it will behave. You might need full length darks (same as your lights) to remove the amp glow. Maybe a user will come in on this.

13 hours ago, TareqPhoto said:

I think i am going with 31mm at the end, i gonna buy a mono camera so it will be fine with smaller sizes filters, i don't see myself going with DSLR for my DSO imaging, and if i will use a DSLR then i simple buy a cheaper brands larger size, it is not worthy i use Astrodon with DSLR anyway so i must buy larger, a mono camera it will be my main imaging camera, later when i modify my DSLR then i can think about larger filters cheaper options.

Why would you shoot through filters with a DSLR? You could shoot Ha but you'd find it very frustrating after using Ha in a mono camera. 

You say you found a cheaper supplier than FLO but did you find a more reliable dealer or one with a better returns policy? I very much doubt it. I never, never buy astro equipment on price.

Olly