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Auto guiding with a very sensitive IR guide camera, like the IMX462m

Acquisition Guiding Seeing Conditions Deep Sky
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AstroShed avatar
AstroShed avatar
Looking for people opinions, I have read that guiding in IR can help with poor seeing and cut through the turbulence somewhat, and with the newer 462m sensor cameras, (I have just got the Touptek variant) which is basically an upgraded 290m sensor, they are super sensitive in the IR end of the spectrum, so with a good 850nm IR pass filter am going to try this out.
Just wondering is anyone does this or has at least tried it out..
Thankks for reading.
Tony Gondola avatar
Tony Gondola avatar
I have and it made a huge difference in my RMS error getting me down into 0.2" RMS range on most nights. Going IR is possibly the easiest way to improve guiding performance.
AstroShed avatar
AstroShed avatar
Tony Gondola:
I have and it made a huge difference in my RMS error getting me down into 0.2" RMS range on most nights. Going IR is possibly the easiest way to improve guiding performance.

Great,
That sounds promising, can you tell me what camera you use and which IR pass filter, if you don’t mind..👍🏻
Tony Gondola avatar
Tony Gondola avatar
AstroShed:
Tony Gondola:
I have and it made a huge difference in my RMS error getting me down into 0.2" RMS range on most nights. Going IR is possibly the easiest way to improve guiding performance.

Great,
That sounds promising, can you tell me what camera you use and which IR pass filter, if you don’t mind..👍🏻

Sure, the camera is an uncooled ZWO 585 MC. The filter is from SVBony.
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Dunk avatar
Dunk avatar
Tony Gondola avatar
Tony Gondola avatar
It's interesting that he didn't see much of a difference as that hasn't been my experience. I wonder if the small aperture and focal length of the guide scope he used made a difference in the response? It might have just been less sensitive to seeing in the first place.
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V avatar
V avatar
I've been using IR for the last year or so, with my ASI120MM Mini I saw my RMS go from .8ish to 0.3-.4 typically. Pairs excellently when you also image in NIR, the reduction on guiding and seeing compounds, and you get incredibly sharp results.
Samuel Warfel avatar
Samuel Warfel avatar
AstroShed:
Looking for people opinions, I have read that guiding in IR can help with poor seeing and cut through the turbulence somewhat, and with the newer 462m sensor cameras, (I have just got the Touptek variant) which is basically an upgraded 290m sensor, they are super sensitive in the IR end of the spectrum, so with a good 850nm IR pass filter am going to try this out.
Just wondering is anyone does this or has at least tried it out..
Thankks for reading.

Think this would be worth doing with a ZWO ASI220mm mini? Or do I need increased sensitivity?  Looks to be about 60% around 800nm.
I’m also not finding an 865nm SVBONY filter, what’s the model number? I just see the one in the 600nms
Raúl Hussein avatar
Raúl Hussein avatar
AstroShed:
Looking for people opinions, I have read that guiding in IR can help with poor seeing and cut through the turbulence somewhat, and with the newer 462m sensor cameras, (I have just got the Touptek variant) which is basically an upgraded 290m sensor, they are super sensitive in the IR end of the spectrum, so with a good 850nm IR pass filter am going to try this out.
Just wondering is anyone does this or has at least tried it out..
Thankks for reading.



It is a good approach and it is not necessary to be in NIR, with a high-pass filter near 600nm it gives good results and there are different options, also many cameras have their best performance in that region of the spectrum (eliminating blue and green is a good strategy).

I think that its usefulness also depends on other factors such as resolution, speed of the guiding optics and the region of the sky. There are not many stars in F7+ high-resolution galaxy season and all the light possible is necessary. I have suffered this.
AstroShed avatar
AstroShed avatar
Thanks all, some interesting and positive posts here, I will be trying it out soon with my new Touptek 462m guide camera and the ZWO 850nm IR pass filter, on my skywatcher Evoguide 50 ED guide scope @ 242mm fl, 2.4”/pixel, It will be guiding my Esprit 100 with QHY268m or OSC cameras @ 1.41”/pixel.
AstroShed avatar
AstroShed avatar
Samuel Warfel:
AstroShed:
Looking for people opinions, I have read that guiding in IR can help with poor seeing and cut through the turbulence somewhat, and with the newer 462m sensor cameras, (I have just got the Touptek variant) which is basically an upgraded 290m sensor, they are super sensitive in the IR end of the spectrum, so with a good 850nm IR pass filter am going to try this out.
Just wondering is anyone does this or has at least tried it out..
Thankks for reading.

Think this would be worth doing with a ZWO ASI220mm mini? Or do I need increased sensitivity?  Looks to be about 60% around 800nm.
I’m also not finding an 865nm SVBONY filter, what’s the model number? I just see the one in the 600nms

This is the ZWO filter I have got, if it helps.

https://www.aliexpress.com/item/4000922318515.html?src=google&pdp_npi=4%40dis!GBP!19.09!19.09!!!!!%40!10000011125214437!ppc!!!&src=google&albch=shopping&acnt=494-037-6276&isdl=y&slnk=&plac=&mtctp=&albbt=Google_7_shopping&aff_platform=google&aff_short_key=UneMJZVf&gclsrc=aw.ds&&albagn=888888&&ds_e_adid=&ds_e_matchtype=&ds_e_device=c&ds_e_network=x&ds_e_product_group_id=&ds_e_product_id=en4000922318515&ds_e_product_merchant_id=5356860590&ds_e_product_country=GB&ds_e_product_language=en&ds_e_product_channel=online&ds_e_product_store_id=&ds_url_v=2&albcp=17859500389&albag=&isSmbAutoCall=false&needSmbHouyi=false&gad_source=1&gbraid=0AAAAADznYb87_gVk7odLHTP1r_vpVm5Gh&gclid=EAIaIQobChMIyayTy7H8igMVw5hQBh25uR2nEAQYBCABEgJuFPD_BwE
Raúl Hussein avatar
Raúl Hussein avatar
AstroShed:
Thanks all, some interesting and positive posts here, I will be trying it out soon with my new Touptek 462m guide camera and the ZWO 850nm IR pass filter, on my skywatcher Evoguide 50 ED guide scope @ 242mm fl, 2.4”/pixel, It will be guiding my Esprit 100 with QHY268m or OSC cameras @ 1.41”/pixel.



In this context and in non-galaxy season (because this team would not be the most suitable for it) I find it viable.
Tony Gondola avatar
Tony Gondola avatar
Samuel Warfel:
AstroShed:
Looking for people opinions, I have read that guiding in IR can help with poor seeing and cut through the turbulence somewhat, and with the newer 462m sensor cameras, (I have just got the Touptek variant) which is basically an upgraded 290m sensor, they are super sensitive in the IR end of the spectrum, so with a good 850nm IR pass filter am going to try this out.
Just wondering is anyone does this or has at least tried it out..
Thankks for reading.

Think this would be worth doing with a ZWO ASI220mm mini? Or do I need increased sensitivity?  Looks to be about 60% around 800nm.
I’m also not finding an 865nm SVBONY filter, what’s the model number? I just see the one in the 600nms

It's the 685nm filter
Tony Gondola avatar
Tony Gondola avatar
You can also get good results with a simple 25A red filter. It's not as aggressive so it might help with cameras that have less sensitivity in the near IR.
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Scott Badger avatar
Scott Badger avatar
But does better guiding with a red/IR filter really improve your images? In my experience, so long as my guiding RMS is 25% (or less) of my seeing, then the fwhm of a 5 to 10 minute image will be the same as a 4 second image and better guiding isn't going to improve anything. For example, if seeing is 3" then total RMS less than 0.75" is just bragging rights…..

Cheers,
Scott
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Tony Gondola avatar
Tony Gondola avatar
Scott Badger:
But does better guiding with a red/IR filter really improve your images? In my experience, so long as my guiding RMS is 25% (or less) of my seeing, then the fwhm of a 5 to 10 minute image will be the same as a 4 second image and better guiding isn't going to improve anything. For example, if seeing is 3" then total RMS less than 0.75" is just bragging rights.....

Cheers,
Scott

I believe it does with a few caveats which may have to do with how I work. As you know, seeing is variable on short time scales. If you're making longer subs as in the 5 to 10 min range you mentioned, it probably won't make a huge difference but because all the variations in guiding error and seeing have all blended together. In my case, I typically shoot much shorter subs. lately, just 15 sec. What is see in my data is that there can be a substantial difference in fwhm from frame to frame. With so many frames you can remove the seeing bloated fwhm frames from the stack, resulting in a higher resolution image. You can beat the seeing to a certain degree. A lucky imaging concept really, just not as extream as used on the Moon or Planets because of limitations in DSO object brightness but, it still has an effect. Of course all of the above only applies to modern, low read noise CMOS cameras.
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Scott Badger avatar
Scott Badger avatar
Tony Gondola:
I believe it does with a few caveats which may have to do with how I work. As you know, seeing is variable on short time scales. If you're making longer subs as in the 5 to 10 min range you mentioned, it probably won't make a huge difference but because all the variations in guiding error and seeing have all blended together. In my case, I typically shoot much shorter subs. lately, just 15 sec. What is see in my data is that there can be a substantial difference in fwhm from frame to frame. With so many frames you can remove the seeing bloated fwhm frames from the stack, resulting in a higher resolution image. You can beat the seeing to a certain degree. A lucky imaging concept really, just not as extream as used on the Moon or Planets because of limitations in DSO object brightness but, it still has an effect. Of course all of the above only applies to modern, low read noise CMOS cameras.

As seeing deteriorates it usually becomes more variable as well, so you're right that the variation in short exposures increases while longer exposures not so much, but at 15 second exposures, how much effect is guiding having anyhow other than preventing drift over multiple exposures?

Cheers,
Scott
Tony Gondola avatar
Tony Gondola avatar
Scott Badger:
Tony Gondola:
I believe it does with a few caveats which may have to do with how I work. As you know, seeing is variable on short time scales. If you're making longer subs as in the 5 to 10 min range you mentioned, it probably won't make a huge difference but because all the variations in guiding error and seeing have all blended together. In my case, I typically shoot much shorter subs. lately, just 15 sec. What is see in my data is that there can be a substantial difference in fwhm from frame to frame. With so many frames you can remove the seeing bloated fwhm frames from the stack, resulting in a higher resolution image. You can beat the seeing to a certain degree. A lucky imaging concept really, just not as extream as used on the Moon or Planets because of limitations in DSO object brightness but, it still has an effect. Of course all of the above only applies to modern, low read noise CMOS cameras.

As seeing deteriorates it usually becomes more variable as well, so you're right that the variation in short exposures increases while longer exposures not so much, but at 15 second exposures, how much effect is guiding having anyhow other than preventing drift over multiple exposures?

Cheers,
Scott

I can't tell you in detail because I haven't made the study but I can tell you what I've observed. In NINA, as I watch the frames come in and am tightly zoomed in so I can see what the stars are doing at the pixel level, I can see the variation caused not only by seeing but also by guiding. If guiding starts to degrade to lets say 0.6" or if the RMS error of one axis is much greater than the other, you can certainly see the effect on the roundness of the star images. I'm shooting at an image scale of 0.66" per pixel, 150mm aperture and 900mm FL.

I think the degree to which guiding and for that matter, seeing variation effects the image, very much depends on imaging scale and focal length. I would agree that guiding better than 0.3" RMS would be wasted if your shooting at 400mm with a 60mm aperture. That said, if a person's guiding can be improved to a noticeable degree with a $12.00 filter (25A), why not do it?
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Ashraf AbuSara avatar
Ashraf AbuSara avatar
I'll give this a try with my E160ED. Going to get the PlayerOne Ceres 426m and combine it with IR pass filter and see if it works with my OAG and the HAE69c. I'd imagine at f/3.3 I should still get enough light despite the filter.
Scott Badger avatar
Scott Badger avatar
Tony Gondola:
I can't tell you in detail because I haven't made the study but I can tell you what I've observed. In NINA, as I watch the frames come in and am tightly zoomed in so I can see what the stars are doing at the pixel level, I can see the variation caused not only by seeing but also by guiding. If guiding starts to degrade to lets say 0.6" or if the RMS error of one axis is much greater than the other, you can certainly see the effect on the roundness of the star images. I'm shooting at an image scale of 0.66" per pixel, 150mm aperture and 900mm FL.

At what seeing do your stars bloat at 0.6" RMS? For me it would need to be better than 2.5". If DEC and RA RMS are significantly different, though, roundness can be affected even at lower total RMS.
That said, if a person's guiding can be improved to a noticeable degree with a $12.00 filter (25A), why not do it?

Can't argue with that! : )

Cheers,
Scott
Tony Gondola avatar
Tony Gondola avatar
Scott Badger:
Tony Gondola:
I can't tell you in detail because I haven't made the study but I can tell you what I've observed. In NINA, as I watch the frames come in and am tightly zoomed in so I can see what the stars are doing at the pixel level, I can see the variation caused not only by seeing but also by guiding. If guiding starts to degrade to lets say 0.6" or if the RMS error of one axis is much greater than the other, you can certainly see the effect on the roundness of the star images. I'm shooting at an image scale of 0.66" per pixel, 150mm aperture and 900mm FL.

At what seeing do your stars bloat at 0.6" RMS? For me it would need to be better than 2.5". If DEC and RA RMS are significantly different, though, roundness can be affected even at lower total RMS.
That said, if a person's guiding can be improved to a noticeable degree with a $12.00 filter (25A), why not do it?

Can't argue with that! : )

Cheers,
Scott

When I get some time I'll try to collect data on this so I can present it a little more coherently!
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AstroShed avatar
AstroShed avatar
All really interesting stuff, thanks for the input all. 👍🏻