Hi Astro Community,
I recently bought the ToupTek CMOS ATR3CMOS09000KPA (IMX533) camera. These are the same camera rebranded as RisingCam, Altair, Omegon, and others. I am looking for assistance interpreting the data to find unity gain.
The manufacturer claims unity gain is at 300 but never responded when I asked if that was in High-Gain-Mode (HGM) or not. The user manual states the gain ratio is 3.05. I am assuming this is a multiplier?
Looking at the data below, it looks to me the Unity Gain is probably close to what ToupTek says—300, but the data doesn't clarify in what mode. So, one might assume in "normal" mode (I.E. without checking the boxes for HGM or HFW).
So if that is the case, and if the gain ratio is indeed a multiplier of 3.05, then perhaps unity gain is 100 when in High-Conversion-Gain (HGM).
In other words . . . gain set to 100 in HCG Mode X 3.05 (gain ratio) = New Gain of 305— close to what the manufacturer recommends. My conclusion is that unity gain is 300 without HGM engaged . . . and 100 with HGM engaged.
Thoughts?
Data follows . . .
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I'd use SharpCap sensor analysis tool to derive the actual camera parameters whether in High Gain mode or otherwise.
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andrea tasselli:
I'd use SharpCap sensor analysis tool to derive the actual camera parameters whether in High Gain mode or otherwise.
Thannks Andrea,
I thought it a good idea, so I gave it a shot. Unfortunately, SharpCap wouldn't recognize my camera. I Googled if SharpCap works with ToupTek and this is what I found . . .
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Tommy Mastro:
andrea tasselli:
I'd use SharpCap sensor analysis tool to derive the actual camera parameters whether in High Gain mode or otherwise.
Thannks Andrea,
I thought it a good idea, so I gave it a shot. Unfortunately, SharpCap wouldn't recognize my camera. I Googled if SharpCap works with ToupTek and this is what I found . . .
That's sad news. You could try the ASCOM driver but not sure the results would be dependable.
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andrea tasselli:
Tommy Mastro:
andrea tasselli:
I'd use SharpCap sensor analysis tool to derive the actual camera parameters whether in High Gain mode or otherwise.
Thannks Andrea,
I thought it a good idea, so I gave it a shot. Unfortunately, SharpCap wouldn't recognize my camera. I Googled if SharpCap works with ToupTek and this is what I found . . .
That's sad news. You could try the ASCOM driver but not sure the results would be dependable.
No luck with the ASCOM driver. I am attempting the DirectShow driver, which shows the camera in the camera list but will not connect to it. I keep getting an error message.
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If you have PI you can use the script BasicCCDParameters to evaluate the performance hence the gain at any point and it only requires darks, bias and flats. Isn't all automated as in Sharpcap but at least gives you a potential validation of your basic assumptions.
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There are discussions around the internet, bottom line:
No HCG: unity gain ~ 300 (actually somewhere between 301 and 309)
HCG: unity gain close to 100
I use 101 with HCG and works great.
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There are discussions around the internet, bottom line:
No HCG: unity gain ~ 300 (actually somewhere between 301 and 309)
HCG: unity gain close to 100
I use 101 with HCG and works great
Thanks Dkamen.
I'm starting to agree with the web voices as well, but I read a lot of conflicting info. I emailed tech support of the manufacturer (ToupTek) and hope to hear back soon.
I will keep everyone posted.
In the meanwhile, I'll be shooting at gain 100 in HGM and low noise mode (LNM or Ultra Mode in NINA). At least I know the affect of Low noise mode because it was included in the manufacturer's sensor analysis.
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Considering the Gain ratio of 3.05... do you think that LCG Gain 305 = HCG Gain 100 ?
I use HCG Gain 100 with my duoband filter and LCG Gain 100 for broadband.
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Marc V:
Considering the Gain ratio of 3.05... do you think that LCG Gain 305 = HCG Gain 100 ?
I use HCG Gain 100 with my duoband filter and LCG Gain 100 for broadband.
Hi Marc - from what I'm reading, I would still use HGM with broadband - or choose gain 300 in LGM for broadband.
Instead, I would use different exposure times to compensate for the different filters/targets. But I'm no expert so take my advice with a grain of salt!
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There are discussions around the internet, bottom line:
No HCG: unity gain ~ 300 (actually somewhere between 301 and 309)
HCG: unity gain close to 100
I use 101 with HCG and works great.
That's a good guideline, what offset are you using?
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Milen Markov:
There are discussions around the internet, bottom line:
No HCG: unity gain ~ 300 (actually somewhere between 301 and 309)
HCG: unity gain close to 100
I use 101 with HCG and works great.
That's a good guideline, what offset are you using?
50. It is a little pitched, could have used 10 on most occasions but it does no harm and with offset it is better to be safe than sorry. 50 means the same darks work with all my scopes, from the reduced Newt which is f/4.9 to the Mak which is f/12.
Cheers,
D.
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Milen Markov:
There are discussions around the internet, bottom line:
No HCG: unity gain ~ 300 (actually somewhere between 301 and 309)
HCG: unity gain close to 100
I use 101 with HCG and works great.
That's a good guideline, what offset are you using?
50. It is a little pitched, could have used 10 on most occasions but it does no harm and with offset it is better to be safe than sorry. 50 means the same darks work with all my scopes, from the reduced Newt which is f/4.9 to the Mak which is f/12.
Cheers,
D.
Hi again! I asked the manufacturer and he recommended an offset of 400... It seemed strange to me, so I'm looking for more information...
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Offset only becomes a problem if you set it too low, so you can't go wrong with 400.
400 would work for higher than unity gain (it would also work for unity) so it gives you more flexibility.
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I calculated my offset to be around 325, so not too far off. Offset is easy to figure out. Just Google how to set offset. There is a procedure for it that takes 3 minutes.
An accurate unity gain is a little more difficult to figure out IMHO.
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