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Thoughts On Chroma LoGlow?

Astrophotography DSO Imaging
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#1 gfstallin

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Posted 19 January 2025 - 06:57 PM

I have an early start on galaxy season, largely due to a tree beloved by people who hate astronomy and probably puppies. Some of these people include my wife and neighbors who are also close friends, so that healthiest of trees is staying. 

 

I'm in a Bortle 8/9 zone and eyeing integration times upwards of 40-50 hours per galaxy target at f/7 (C11 Edge) with my mono camera. Much of this will be luminance. 20 hours of luminance on M81 looks very promising. I'm looking for any edge I can get. I've come across the Chroma LoGlow filter and I was wondering what others think of it on broadband targets like galaxies? Is there a noticeable difference (improvement) between this and a "normal" luminance filter? 

 

I realize no filter is going to turn my location near Washington D.C. into a Bortle 1 paradise. I know the best filter for broadband is called "load observatory into flatbed truck and drive 5 hours to the mountains." Perhaps one day. For now, I'm looking to maximize what I have where I have it. I'm looking for even a small SNR increase. This isn't necessarily to reduce integration time. I have an observatory and image from a warm house while streaming movies so an additional 5 or 10 hours luminance isn't a big deal. I just would like the best data I can get going in that I can get from where I image. 

 

George 

 


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#2 andysea

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Posted 19 January 2025 - 07:11 PM

I can't provide any feedback on the filter itself but I am curious how you would integrate it in a monochrome imaging train. Would you put it in front of the filter wheel so that your LRGB data is all taken through that filter?



#3 Poynting

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Posted 19 January 2025 - 08:39 PM

Keep in mind that the Lo-Glow is 1.1mm thick, whereas the others are 3mm thick.


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#4 licho52

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Posted 19 January 2025 - 09:18 PM

There's no cure for LP in broadband luminance. Use L filter.



#5 gfstallin

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Posted 19 January 2025 - 09:59 PM

Keep in mind that the Lo-Glow is 1.1mm thick, whereas the others are 3mm thick.

This...I hadn't considered. My other filters (Antlia SHO 3nm and ZWO R,G,B) are actually 2mm thick, but I imagine this would represent a considerable focus change. I'm..OK on backfocus. I've gotten to a place mentally where I can accept that I'm not going to be at 146.05mm backfocus at all times per requirements for my reducer. My obsessive tendencies being what they are, I'll still probably chew on this though for a while.   

 

George



#6 gfstallin

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Posted 19 January 2025 - 10:38 PM

I can't provide any feedback on the filter itself but I am curious how you would integrate it in a monochrome imaging train. Would you put it in front of the filter wheel so that your LRGB data is all taken through that filter?

Andy, 

 

I would put this into the filter wheel in place of the L filter I normally use. This filter has the basic characteristics of all luminance filters, but with does not pass  parts of the spectrum specific to different types of lighting (mercury and sodium vapor). It is much less aggressive than a typical light pollution filter in terms of cutting anything other than UV and IR. 

 

George


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#7 Umasscrew39

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Posted 20 January 2025 - 10:01 AM

I use it as part of a complete set of Chroma LoGlowRGB filters on my C11" EdgeHD @ f/10 (I got rid of the reducer).   It works fine but is no magic bullet in my Bortle 7 sky.  Compared to the Optolong L-Pro filter that I have used in the past, it gives a better overall look, in my experience.     


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#8 dghent

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Posted 20 January 2025 - 10:26 AM

LP filters will be a frustrating experience. Much of the LP in the DC and NOVA area is broadband anyway. The cure for this is lots of data and patience with gradient removal tools. Filters are no magic bullet.
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#9 gfstallin

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Posted 20 January 2025 - 03:14 PM

LP filters will be a frustrating experience. Much of the LP in the DC and NOVA area is broadband anyway. The cure for this is lots of data and patience with gradient removal tools. Filters are no magic bullet.

Completely agreed. I had no intention of using an LP filter, at least not one that takes out such a large chunk of the visible spectrum as many LP filters. The Chroma LoGlow and Optolong L-Pro, which is broadly similar, both offer transmission graphs that are very similar to traditional luminance filters, only with dips at very specific bands related to specific types of light pollution. If this filter can increase SNR even in the slightest, then it might be worth it. 

 

I agree on the sources of light pollution in this area either being mostly or increasingly becoming largely broadband. I'm coming at this from a planetary imaging perspective where we do any little thing we can to squeeze out that extra 0.5% increase in detail. I've put ice packs on the back of OTAs, for example. I stuck a C9.25 in a commercial refrigerator because I didn't have time to acclimate outside. I check collimation and make necessary adjustments on both sides of the meridian so that miniscule changes in collimation due to mirror flop or other issues do not impact seeing. None of these tricks are magic bullets, especially since atmospheric seeing is 99% of the game, but they are things we can control to make the best of good luck when it shows up on screen. I've only been doing DSO imaging for about 15 months though, so I have a lot to learn. There are books every year written on every aspect of DSO imaging, so it should not have come as a surprise. There's a book a decade dedicated to planetary imaging lol.gif . In that vein, a miniscule but measurable increase in SNR might be worth it, sort of like the difference I noted in going from 7nm to 3nm SHO filters. It wasn't night and day; I had to really look, but it was enough that I'm not using 7nm filters at this time. If others' experience with this specific filter suggest that some positive difference is visible or not visible at all, that's useful data.

 

Basically, I'm trying to improve my luminance data. The answer might be there isn't a whole lot I can do, which I can live with. 

 

M81 Bin1-600-Luminance ONly

This is where I'm at right now. I have some gradients going on that I haven't been able to remove. Perhaps more hours of integration in luminance will help, and I'm almost definitely going to try that once I tackle R,G,B. I'm also becoming keenly aware that obsessive tendencies work extremely well in DSO imaging, though they can be problematic for moving on to the next filter. 

 

George



#10 Rasfahan

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Posted 20 January 2025 - 06:19 PM

I’ve done a lot of broadband imaging from LP. I‘ve started out using an Astronomik CLS which is similar to the NoGlow. I‘ve found it very difficult to get good colors when using it as an L replacement. Also, as you increase integration time in high Bortle, you‘ll see more and more complex gradients - I think PI MARS is then helpful. But what the gradient correction and noise reduction then leave is large-scale colour noise which will be the final limit of your imaging. Getting rid of it will require ever-increasing integration time, dozens and dozens of hours. No silver bullet, unfortunately.



#11 XM381

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Posted 20 January 2025 - 07:39 PM

I have a similar issue; a tree that I'm just certain is "unhealthy", but the wife isn't buying it.... that was until I sweetened the pot with new hardwood floors. She now has "concerns" of the risk of damaging the house in high winds and/or fire hazard. 

 

Although a little hard so see from my house, but I think your tree may be looking sickly too! 

 

Got nothing for you in regards to filters.

 

Good luck.


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#12 gfstallin

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Posted 20 January 2025 - 09:30 PM

I have a similar issue; a tree that I'm just certain is "unhealthy", but the wife isn't buying it.... that was until I sweetened the pot with new hardwood floors. She now has "concerns" of the risk of damaging the house in high winds and/or fire hazard.

 

Although a little hard so see from my house, but I think your tree may be looking sickly too! 

 

 

Good luck.

You see just perfectly. Things were looking up for a while when a beetle infested the tree. It was "distressed" according to an arborist. I thought it was a miracle. That tree would die so that I might live. Alas, what you never hear happening actually happened. The tree survived the infestation and the beetles...disappeared? Sigh....

 

George




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