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lcg vs hcg for narrowband imaging

ToupTek ATR3 CMOS 26000 KMA CMOS Narrowband
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Anderl avatar
Anderl avatar
Hello fellow astro friends, 

i am a new owner of an touptek 2600kma (imx571 mono) and searching for some tips to get the most out of it. 

If i am reading the sensor measurements right the only two useful modes to use are gain 100 lcg and maybe gain 100 together with hcg. 

I am plan on using the lcg for my luminance and rgb imaging, coming from an imx571 color i will probably just use the same exposure time for rgb and maybe a bit shorter for the luminance filter.

the thing i am unsure about is narrowband imaging. I will use 4.5 nm antlia filters. 
can or should i still use the lcg mode with the exposure time i used for my 3nm duo narrowband on osc or do i gain something by using hcg with shorter exposures?

cs
Andi
Brian Puhl avatar
Brian Puhl avatar
I run both a QHY and OGMA IMX571.   Both cameras stay in high gain mode 24/7.   YMMV.   I feel like folks try to make a science out of it, but I prefer to keep it simple.    I've had zero issues with running this route.
Pistachio_Enjoyer avatar
Pistachio_Enjoyer avatar
Risingcam IMX 571 mono owner here, I always image at HCG mode, with ultra mode enabled. I may experiment with LCG mode for HDR targets (i.e. Orion Nebula), but I have yet to see.
Alex Nicholas avatar
Alex Nicholas avatar
Brian Puhl:
I feel like folks try to make a science out of it, but I prefer to keep it simple.

I couldn't agree with this more. 
I see people running different gain and offset settings for LRGB vs Narrowband, and different settings again under dark skies or brighter skies... 

I run gain 100, offset 180, HCG, Ultra mode 100% of the time... I'll shoot 600s subs with narrowband and maximum of 300s with LRGB - but same gain and offset regardless of where I am, or what I'm shooting.
Werner Stumpferl avatar
Werner Stumpferl avatar
I use a QHY600M and QHY268M and I always run both in HighGainMode, Gain 56 Offset 10, Broadband and Lum with 150s and Narrowband with 300 or 600s. No issues.
patrice_so avatar
patrice_so avatar
Hi

User of the TS-Optics rebrand of that camera here. Just like @Brian Puhl , I like to keep it simple. Important is to make the most of the dynamic range without burning anything. So... 
- HCG mode on with ultra for everything except ... 
- LCG mode on with ultra and extended full well for very bright targets with broadband filters (i.e. LRGB filters for M42 and M45 where subs are also much shorter). 
That's it. 

You own a great came. Have fun with it !

CS

Patrice
Brian Puhl avatar
Brian Puhl avatar
On that note, I don't run extended full well, for some reason I'm having issues calibrating with it turned on.    

Anyone have a similar experience?
patrice_so avatar
patrice_so avatar
Brian Puhl:
On that note, I don't run extended full well, for some reason I'm having issues calibrating with it turned on.    

Anyone have a similar experience?

Indeed. Up to now, I looked at it from the perspective of my experience with my ASI294MC pro and concluded that I had a slight flat problem. However, looking at it after reading your message, it seems that I have an issue of flat over correction, in spite of having flats made according the usual rules (and I got picky on that because of the same ASI294MC pro...).  The problem is light, but real. 

Is your issue overcorrection @Brian Puhl ?
Brian Puhl avatar
Brian Puhl avatar
patrice_so:
Brian Puhl:
On that note, I don't run extended full well, for some reason I'm having issues calibrating with it turned on.    

Anyone have a similar experience?

Indeed. Up to now, I looked at it from the perspective of my experience with my ASI294MC pro and concluded that I had a slight flat problem. However, looking at it after reading your message, it seems that I have an issue of flat over correction, in spite of having flats made according the usual rules (and I got picky on that because of the same ASI294MC pro...).  The problem is light, but real. 

Is your issue overcorrection @Brian Puhl ?



No, I think mines at the bias level.   I'm getting faint grid patterns, if I remember correctly.   It's been a few months since I messed with it, so my memory is fuzzy.