Filter advice for planetary and lunar

[Simon128D]

Hi all,
I am thinking of getting a filter or two to aid me in my planetary and lunar imaging. I use a CPC1100 with an ZWO ASI 290MC

I notice there are several IR pass filters that have different band passes, for eg 642, 742 and 807 being the most common. 
I don't seem to have the head on me to figure out which filter will work best for me. I mainly want to use an IR pass on Saturn, Jupiter, Mars and the Moon. 

Is there any one IR pass filter that does a great job on all objects?

Lastly, would I be correct in assuming that when imaging in IR the use of an ADC is not longer needed as you are only working with one wave length? 

Thanks
Simon

[Cosmic Geoff]

I doubt that it matters much which IR pass filter you use unless you have some advanced project in mind, rather than wanting to see what difference it makes.  I use the IR pass filter from ZWO (850nm) that costs about £25. The longer wavelength pass filters may give greater suppression of atmospheric disturbance.

Using an IR-pass filter should render the ADC  much less necessary (or unnecessary), but if you are using a UV-IR cut filter and an IR pass filter in turn, leaving the ADC in place saves you the bother of removing kit and refocusing.  In my case I just rotate the filter wheel.

[vlaiv]

It is a tradeoff.

Longer wavelengths are less disturbed by seeing.

Longer wavelengths offer less resolving power (800nm will have only half of resolution of say 400nm as there is linear dependence on max resolution vs wavelength).

Most sensors are less sensitive in longer wavelengths.

Bandpass also plays a part. Wider filters are less sharp then narrow band ones (all else being equal).

[Simon128D]

Thank you both for your input. That has been really helpful and making me unserdtand it a bit better. 
I did not stop to think or realise that longer wavelengths would have less resolution and vice versa. 
With that in mind and applying my own logic would somewhere in the middle be a good trade of? I was thinking of this filter. 
https://www.firstlightoptics.com/uv-ir-filters/ak_pp_742-ir_125.html

I typically get poor to average seeing at my location and with Saturn so slow I mainly want to have a chance at getting some good imagages and not have to battle with terrible atmospheric condtions. 

I do currently have an IR-Cut filter on the nose piece of the camera but surely I would remove that in place of the IR Pass when wanting to image in IR? 

[Cosmic Geoff]

6 minutes ago, Simon128D said:

I do currently have an IR-Cut filter on the nose piece of the camera but surely I would remove that in place of the IR Pass when wanting to image in IR? 

Definitely, yes.

I found that with an ASI224MC camera, using an IR-pass filter gave sharper images on Saturn, but with an ASI462MC  it fails to do so. 

[Kon]

I have 610, 685 and 742. I agree with what Vlaiv and Geoff said. I have not managed a good Saturn this apparition as I see a boiling effect even with the IR filters. My better IR image was from the 742 filter but I usually prefer the 610/685 as you can pull more details. See my post here for comparison with the two filters (you probably need to scroll down a bit to see the 685):

https://stargazerslounge.com/topic/412576-saturn-with-tethys-and-rhea-110823/

I have the 462mc which is quite sensitive to IR. 

If I were you, I would go for a 610 to 685 as it will have more resolving power especially with Jupiter higher this year. You may want to consider the Astromania set of filters (that's what I use in addition to the ZWO 742); you also get a nice UV and methane filter. They are currently on offer in Amazon:

https://www.amazon.co.uk/Astromania-1-25-Inch-Specialized-Planetary-Ultraviolet/dp/B07C3K7J16?th=1

I made a little review a while back:

https://stargazerslounge.com/topic/409518-astromania-filters-for-planetary-imaging-review/

 

[Simon128D]

Thank very much indeed Kon. 
Based on what you said there I will go with your advice. 

Am I correct in saying that I would be removing my IR-Cut filter and using the IR-Pass instead? I know this seems like a dumb a very obvious thing but I have seen conflicting posts in several places saying they use their IR pass along with their IR cut but that seems illogical to me!? 

[Simon128D]

Okay so I am thinking this might be the best option for me. Hoping this will be a nice match for my CPC1100 and ASI 290MC

https://www.firstlightoptics.com/uv-ir-filters/astronomik-proplanet-642-bp-ir-pass-filter.html

[Cosmic Geoff]

48 minutes ago, Simon128D said:

Am I correct in saying that I would be removing my IR-Cut filter and using the IR-Pass instead? I know this seems like a dumb a very obvious thing but I have seen conflicting posts in several places saying they use their IR pass along with their IR cut but that seems illogical to me!? 

You shouldn't believe everything you read online.  🙂 Cutting the IR with  visual pass filter and then adding a IR pass (and visual cut) filter is going to mean you don't pass much of anything.

The only reason I can think of for using two filters together is to suppress an unwanted pass-band.

[Kon]

1 hour ago, Simon128D said:

Am I correct in saying that I would be removing my IR-Cut filter and using the IR-Pass instead? I know this seems like a dumb a very obvious thing but I have seen conflicting posts in several places saying they use their IR pass along with their IR cut but that seems illogical to me!? 

Yes you need to remove the UV/IR cut filter and use your pass one.

Unless it was some confusion(?); for Venus you may want an IR cut only but no UV cut (Astronomik have this) and then stack it with a W47 filter. Bus as Geoff said you will not get IR through like this.

[Simon128D]

Thanks for your advice all. 
Filter arrived yesterday, now I just need a clear night.