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Talk me out of future-proofing myself with filters

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#1 DRK73

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Posted 11 March 2021 - 02:46 PM

For my 294mm, I've got a single 1.25" H-alpha filter. I've been hesitant to get any more 1.25" filters because I know that 31mm is likely a better size given my expected use of the camera (which I've had for well over a month now and not taken out as I complete projects I'd started with my asi533...)...

 

But...I'm also aware in the back of my mind that the asi2600mm exists and am thinking that THAT sounds like a nice camera, indeed, and so would be best looking at 36mm filters.

 

But 36mm are overkill on the 294mm, so what to do? What to do?...



#2 TxStars

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Posted 11 March 2021 - 02:54 PM

"future-proofing"

Buy some good 2" filters and EFW and be done with it..  LoL  

There is almost always something you will "Need" to buy.


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#3 endless-sky

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Posted 11 March 2021 - 02:54 PM

If you plan on buying a different camera in the future that would benefit from larger filters, I would "buy once, cry once". If money is an issue, you could always buy one filter at a time.

 

I definitely wouldn't want to pay the price twice for different size filters, if I had in mind to upgrade my camera in the near future.


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#4 Stelios

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Posted 11 March 2021 - 03:06 PM

How do you figure 31mm is a better size? Given your scopes, 1.25" is just fine if you are using a ZWO 8-pos FW (see this calculator).

 

The FW used by the 2600MM is different than the one for the 294MM (in both cases talking about 36mm filters). Although you would be able to keep the same filters, you will need to purchase a new filter wheel.

 

In general, future-proofing is a losing proposition unless the future you are talking about will take place within a year or so. Further out, and you have no real idea as to what will be available. And you can usually sell the equipment (filters) you no longer want. If the equipment is relatively inexpensive (such as ZWO filters) you will lose a very small amount. If you are investing in Astrodon or Chroma... then you may want to "future proof."

 

I strongly suspect your best approach is to continue getting 1.25" filters. 


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#5 DRK73

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Posted 11 March 2021 - 03:23 PM

How do you figure 31mm is a better size? Given your scopes, 1.25" is just fine if you are using a ZWO 8-pos FW (see this calculator).

 

The FW used by the 2600MM is different than the one for the 294MM (in both cases talking about 36mm filters). Although you would be able to keep the same filters, you will need to purchase a new filter wheel.

 

In general, future-proofing is a losing proposition unless the future you are talking about will take place within a year or so. Further out, and you have no real idea as to what will be available. And you can usually sell the equipment (filters) you no longer want. If the equipment is relatively inexpensive (such as ZWO filters) you will lose a very small amount. If you are investing in Astrodon or Chroma... then you may want to "future proof."

 

I strongly suspect your best approach is to continue getting 1.25" filters. 

 

I used Astronomy.Tools. And - am an idiot. 1.25" is slightly larger than 31mm.

 

Thank you, Stelios, for the smack in the face that I needed! 



#6 imtl

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Posted 11 March 2021 - 03:26 PM

In a year's time or two years, there will be another new camera, and other filters, and another new scope and more and more and more and...

 

Don't fall into the pit of chasing technology the minute something new comes out. Unless you have the money.

 

People are rushing now to buy the ASI2600mm pro partly because a lot of us were waiting for a cooled APS-C mono cmos for years. It's hyped. But getting a bigger sensor comes with it's own challenges. If you have a system that can support it then great. The bigger the sensor the harder it is for the system. Filter size is only one parameter. Vignetting is the least important problem because you can fix it by going larger. With filters, adapters etc. But getting you FOV flat with pinpoint stars and no aberrations, that's the challenge. And that is way more difficult than filter size. 

 

I do not recommend following a "future proofing" path. Or as Stelios put it, if your "future" is only a year away, worry about now.

 

**This is more general comment than aimed towards Dan (OP)


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#7 imtl

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Posted 11 March 2021 - 03:27 PM

I used Astronomy.Tools. And - am an idiot. 1.25" is slightly larger than 31mm.

 

Thank you, Stelios, for the smack in the face that I needed! 

1.25" that is not the clear aperture. The 1.25" clear aperture is smaller than the 31mm.


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#8 DRK73

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Posted 11 March 2021 - 03:29 PM

1.25" that is not the clear aperture. The 1.25" clear aperture is smaller than the 31mm.

Doesn't change the fact that I needed my face smacked. Also shows that I was obsessing over numbers without taking a step back to understand what they meant. So again, I needed a good smacking. 



#9 imtl

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Posted 11 March 2021 - 03:42 PM

Doesn't change the fact that I needed my face smacked. Also shows that I was obsessing over numbers without taking a step back to understand what they meant. So again, I needed a good smacking.


slaphappy.gif


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#10 Stelios

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Posted 11 March 2021 - 04:00 PM

Doesn't change the fact that I needed my face smacked. Also shows that I was obsessing over numbers without taking a step back to understand what they meant. So again, I needed a good smacking. 

1.25" filters are usually between 27 and 28mm clear aperture. They are also mounted. 

 

The key thing to recall is that the sensor to filter distance on the 7 and 8 pos FW's by ZWO is 10mm, but that on the new ASI2600MM and new 7-pos custom-matched FW, it is longer (not sure how much). 

 

Whatever you buy, if you can't afford Chroma or Astrodon, I recommend stretching for Astronomik if you can. In particular their Deep Sky RGB are superb.


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#11 CarolinaBanker

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Posted 11 March 2021 - 04:19 PM

Get a cheap UHC for visual, the Hydrogen beta isn’t as useful as not everything emits in that spectrum. Here’s an interesting article https://www.prairiea...common-nebulae/

#12 imtl

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Posted 11 March 2021 - 04:27 PM

Get a cheap UHC for visual, the Hydrogen beta isn’t as useful as not everything emits in that spectrum. Here’s an interesting article https://www.prairiea...common-nebulae/

He is asking about imaging filters. Not for visual.



#13 Der_Pit

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Posted 12 March 2021 - 06:17 AM

1.25" filters are usually between 27 and 28mm clear aperture. They are also mounted.

Actually less.  The filter thread is 1.125x42tpi, that is 28.57mm outer diameter and usually leaves about 26mm.  The (unmounted) 31mm wheels usally have (also) a thread for the 1.25" filters, so that limits their clear aperture to 28mm.
 

The key thing to recall is that the sensor to filter distance on the 7 and 8 pos FW's by ZWO is 10mm, but that on the new ASI2600MM and new 7-pos custom-matched FW, it is longer (not sure how much).

Removing the tilt plate, with the bolt-on wheel you end up with ~22.5mm.  Depends a bit on the filters.

Edit: Stupid me tongue2.gif .  Also there it's the cutout of the wheel that limits the aperture, so the relevant distance would be around 20mm....
 

Whatever you buy, if you can't afford Chroma or Astrodon, I recommend stretching for Astronomik if you can. In particular their Deep Sky RGB are superb.

+1 on the Astronomiks.  I use the 31mm ones with my 1600.  I had considered Antlias for the 2600, but found no reason not to take the Astronomiks again (they are only ordered though, don't have them yet).

For a refractor, I'd take Chroma over AD because of the higher blue cutoff.

 

And for the TO:  Yes, I'd (strongly) suggest to go for the 36mm.  We'll see how long you can withstand to buy the 2600 grin.gif  (I couldn't)


Edited by Der_Pit, 12 March 2021 - 06:20 AM.

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#14 TareqPhoto

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Posted 15 March 2021 - 06:55 AM

This is a good topic, because i also got QHY294M and i don't know which size of filter to buy [at least 1 or 2 filters only], either 36mm or 2" or 50mm, and it is all about future proofing, but i think from the comments here i should go with minimum smallest filter size it can allow and never worry about future, there might be new things coming so i should care about future in the future.



#15 psugrue

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Posted 15 March 2021 - 11:28 AM

As I think you know, there is no "Right" answer to this. I just went through the same thing. First I went Astrodon because although I am 97% sure the ZWO or whatever would be functionally equivalent from my perspective, I know that 3% doubt would nag at me. "Oh look there is a slight halo. Would I have got that with the Astrodons?" Ahhhh! Then I went 36mm 5 um on the NB and a set of 4 36mm RGBL. Slammed that all in a 7 spot ZWO wheel. This for me is an outrageous amount of money that I can barely justify so the 3 um or the 2 inch were out of the question. I also did not like the idea of spending money on 1.25 and then having to sell them down the road to upgrade. I also like to use my D5 mk ii as well as ZWO cameras. And finally I think that if we are going to see major advancements in tech over the next few years, cameras are the thing that are going to be twice as good and half the price so we are going to want  to upgrade. Will that mean bigger sensors? Maybe.

 

Just remember, these are good first world problems to have.

 

Cheers,

 

Patrick   


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