Astronomic ProPlanet 642 IR Pass Filter for Lunar Imaging - Does it make a difference?

[neil phillips]

50 minutes ago, Lockie said:

It could be dithered out like someone mentioned, and I can test that at some point by stacking a very short run of 100 frames which would literally take a second or so, as apposed to thousands of frames which takes close to a minute.

if a 1 second run which wouldn't allow time for tracking errors to kick in shows the Bayer pattern, I guess we can be pretty sure the above images were dithered by tracking errors from much longer runs. 

I hope that makes sense? 

I will add Chris go was referring to jupiter with hes observations. I think i may have wrongly assumed it would also apply to lunar imaging. Good idea on the test. My best results with large optics was with a IR 685. So this is very good news. Good work Chris

[Chris]

1 minute ago, neil phillips said:

I will add Chris go was referring to jupiter with hes observations. I think i may have wrongly assumed it would also apply to lunar imaging. Good idea on the test. My best results with large optics was with a IR 685. So this is very good news. Good work Chris

Thanks Neil, I just had the thought to go check the individual frames from my AVI files and there isn't any Bayer to dither out! I don't know why I didn't think to check sooner? hehe

 So the difference isn't dithering, but I'm not sure it's a planetary verses Lunar either? After all they are both captured via AVI footage in a very similar fashion....I might be missing something? 

Maybe Chris Go, had very different capture settings? I used RGB24.  

[neil phillips]

36 minutes ago, Lockie said:

That's a fine image from the Capricorn 70mm achro  Yeah perhaps it was bad wording on my part regarding larger aperture and the 850nm filter, although I also read that longer IR wavelengths can soften image detail so maybe the 742 would be the better compromise? 

As Craig suggests it appears softened. After a few tests. i have concluded its not needed. Your losing more than you are gaining. The softened appearance is even worse on already soft optics like my EVO 120

[neil phillips]

10 minutes ago, Lockie said:

Thanks Neil, I just had the thought to go check the individual frames from my AVI files and there isn't any Bayer to dither out! I don't know why I didn't think to check sooner? hehe

 So the difference isn't dithering, but I'm not sure it's a planetary verses Lunar either? After all they are both captured via AVI footage in a very similar fashion....I might be missing something? 

Maybe Chris Go, had very different capture settings? I used RGB24.  

Surely RAW is the better option

[Chris]

35 minutes ago, neil phillips said:

Surely RAW is the better option

I think RAW8 would be about the same, RAW16 would be better for all out image quality (a lot more shades of grey of course, but I don't remember seeing that option). For testing a filter, RGB24 seemed simpler and reduces steps in processing hence reduces sources of error (I think) I think RGB24 takes care of debaying etc and gives you an image with less fuss. 

Oh wait! Maybe I should shoot some footage in RAW8 and see if it leaves the Bayer pattern!? That could well be the difference with Chris Go's experience of the camera. No problem with RGB24 of course. 

Edited April 29, 2021 by Lockie

[neil phillips]

32 minutes ago, Lockie said:

I think RAW8 would be about the same, RAW16 would be better for all out image quality (a lot more shades of grey of course, but I don't remember seeing that option). For testing a filter, RGB24 seemed simpler and reduces steps in processing hence reduces sources of error (I think) I think RGB24 takes care of debaying etc and gives you an image with less fuss. 

Oh wait! Maybe I should shoot some footage in RAW8 and see if it leaves the Bayer pattern!? That could well be the difference with Chris Go's experience of the camera. No problem with RGB24 of course. 

Fair enough. At some point i will try and get IR 685 and see what transpires. But i am very pleased you are finding these results. It seems the chip maybe more versatile than i first thought. Which is great news Chris

[jetstream]

2 hours ago, CraigT82 said:

The thing is that the longer the wavelength the worse your scope's resolving power is.  Radius of airy disc = 1.22λ/D.

So at 850nm your scope is only resolving fine details twice as large as if you were using a blue filter (at 425nm ish). This is why people say it softens the detail... it doesn't so much soften the detail as not capture it at all! 

Good explanation Craig, I was enlightened on this a little while back.

[happy-kat]

Thought I would tack on a test I did yesterday, daytime use of 150 lens inside and no filter gain 100 the camera was collecting enough light to make an image of what I saw by eye (nothing analysed) the 742 filter surprisingly only needed 240ms to create an image. The same image with the IR/UV blocking filter needed 60ms, less again with no filter.

[Ags]

Why would 850nm be "overkill" which makes it sound like too much of a good thing?