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Going mono + heads up for cheapskates

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#51 pippo

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Posted 13 January 2013 - 08:39 AM

Did you use in this example only the analog-gain or also the digital one?

#52 PiotrM

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Posted 13 January 2013 - 08:40 AM

Thats my friend website. He only changed the gain at 820 hex.

#53 pippo

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Posted 13 January 2013 - 09:00 AM

I did not perform a systematic study on this, but I think that, in order to optimize the signal/noise ratio, the following is probably the best strategy:

1) use the x2 digital gain (80 hex register) + the x1.2 reference_potential (2C register) and tune the analog gain to cover the histogram
2) if the 12dB analog gain is not sufficient, use the 820 register to increase the analog_gain beyond the 12dB limit

Will be useful to report systematic tests on these strategies

#54 pippo

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Posted 18 January 2013 - 06:04 AM

Good news,
I contacted Edelmann, Torsten the author of Firecapture.
He reacted very rapidly in a very effective manner: he has implemented the modification of the 3 registers in the beta version build #37.

You can download the code here:

http://firecapture.w...s.de/betas.html

A big thanks to Torsten for his code and his availability to our community!

To manipulate the 3 registers, there are new controls into the GUI under the additional controls (right-click or left-click on the gamma control to open the popup).

You should see:

1) "Gain2x". This controls the digital-gain. Namely which are the bits not considered in the 10bit to 8-bit conversion. The button puts F8 in the register 80 of the sensor. This corresponds to an increase x2 of the signal (independently of the actual value of the analog-gain).

2) "SignalBoost". This controls the reference potential of the AD converter. The button puts 00 in the 2C register of the sensor. This corresponds to an increase x1.2 of the signal (independently of the actual value of the analog-gain).

3) "GainBoost". This sets the analog-gain beyond the 12dB standard limit. It puts 7F in the 820 register of the camera. This corresponds to a 24dB gain level. For the moment the intermediate values of the analog-gain between 40 and 7F are not implemented. If you need these you should use Flycap2 as described above.
Notice that the off-state of this third button (of just this one) does not work, i.e. it does not restore back the standard level of the analog-gain. However, to restore the standard values, you have just to move the standard control of the gain.


On Jupiter (with average turbulence) at f/27 (with a Mak Intes 703 + barlow, Astrotech Voyager manual AZ mount, I have to manually follow the planet! No space for a bigger mount on my balcony) with very short exposition time, no IR filter, and the 3 new buttons activated:

FPS=61
Shutter=4.998ms

I have the following:

Histogramm(min)=0
Histogramm(max)=178
Histogramm=69%
Noise(avg.deviation)=27.09

Not bad (the histogram)!

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#55 chboss

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Posted 20 January 2013 - 04:53 AM

Great stuff I have been using this camera since September... nice for such a cheap piece of equipment. ;)

regards
Chris

#56 pippo

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Posted 20 January 2013 - 06:49 AM

The performances/price ratio is close to infinity! I am considering to buy a second one...

#57 zAmbonii

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Posted 20 January 2013 - 01:16 PM

I had put aside the MV after my first couple of times out because of the gain issue. I need to give it a try again to see if I can get better results! Now if the weather will cooperate some, I would be able to do so.

#58 pippo

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Posted 21 January 2013 - 01:56 AM

I have both the spc900nc and the Firefly and I did some comparative test. Without the register manipulation on planets, the low-light performances of the Firefly are competitive with those of the spc900nc only if the two cameras are used without the IR filter.

However the situation is radically changed with the 3-register manipulation. Indeed with the three button activated, the covered histogram is amplified by a factor of 4.8. The performances of the Firefly become by far superior with respect to those of the spc900nc (in term of the signal/noise ratio for a given shutter time).

I suggest you to always activate the "Gain2x" and "SignalBoost" buttons, and to play with the standard gain-control to cover 60-80% of the histogram. Just in the case that the maximum gain is not sufficient to cover the histogram, the third button "GainBoost" should be used.


#59 Mark Swift

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Posted 23 January 2013 - 06:39 PM

Hello Pippo,

Mark here off the French forum site :-)

Okay, so I've tried the latest Firecapture Beta... I'm some what confused though. Using FlyCap2, I get great result, little noise and a very bright image! Using Firecapture beta however, my results are not so good, the image is darker and there is a lot of noise (If I use the dark frame feature I lose a lot of detail!).

Do you know what causes this?

Question, if we are running x64, do we need to install the x32 version, or will the x64 version work with the new Flycapture beta?

Mark

P.S. Ignore me, I failed to take into account the night mode in firecapture and the effect it had on illumination in the dark, ha ha! :o

#60 pippo

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Posted 24 January 2013 - 01:55 AM

Dear Mark,
could you be more specific?

I get identical results with flycap2 (+register manipulation) and firecapture beta version (if identical settings are used in the two codes).

Could you verify that the settings are identical?

Is the gamma button switched off in firecapture (it increases a lot the noise)?


What do you mean by:

"my results are not so good, the image is darker and there is a lot of noise"

Are you referring to the action of the 3 additional buttons or the "image is darker" with respect to that of flycap2 already without the buttons activated?

Did you try the effect of each button individually?

Can you post a screenshot (with the histogram activated) that illustrates your problem.

#61 Mark Swift

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Posted 24 January 2013 - 05:48 AM

Hello Pippo,

All fixed now!

I've installed 2.4.2.8 x64 and x64 and can get the camera working in Firecapture and PHD (PHD requires you to pick WDM camera).

Does anyone have any experience getting PHD to work, i.e. exposure times etc? Is it better to use the ASCOM drivers here? http://pludov.free.f...om_firefly.html ? I'm not familiar with the software and would be grateful of any assistance, Firecapture on the other hand seems pretty straight forward!

I have 2 cameras and plan to use 1 for guiding and 1 for planetary...

Update: It seems the ASCOM drivers do not work correctly under Windows x64. I have FlyCapture x32 and x64 installed, but when trying to connect to the camera using ASCOM diagnostics I get an error:

Connect Failed...Could not load file or assembly 'FlyCapture2Managed_v100, Version=2.3.3.18, Culture=neutral, PublicKeyToken=76c6583b4a4585f4' or one of its dependencies. The system cannot find the file specified.

Can anyone do this successfully?

Mark


#62 pippo

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Posted 01 February 2013 - 03:07 AM

I post an other image of Jupiter + Europe taken with my un-drive alt-az (manual) mount on the 30th of Jan 2013 a mak intes 703 (7") at f/26.5 with a fair turbulence (pickering scale 5) and an IR filter

http://www.damianpea...m/pickering.htm

FPS=60
Shutter=16.15ms
FPS=3051 (off)
GainBoost=0 (off)
Brightness=140
Exposure=7
SignalBoost=0
Gain=935
Gain2x=0
Gamma=0 (off)
Histogramm(min)=0
Histogramm(max)=139
Histogramm=54%
Noise(avg.deviation)=11.07

Attached Files



#63 ourobouros2k2

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Posted 16 February 2013 - 07:50 PM

I almost pulled the trigger on this as a mono imager for use with my coronado pst, however after reading Piotr's review, it was evident that this camera is prone to newton's rings interference. My current Orion SSAG autoguider (QHY-5) has the same issue with newton's rings, and no amount of twisting the camera eliminates them and they are present no matter what power I use. I assumed it was due to the IR cut filter.

My question is, after removing the lens on the firefly that has the IR cut filter, is the newton rings interference still present and if so, does anyone know a viable workaround? Money is tight right now and I can't get the imager I want and this would be a great temporary solution while I save for an AS120MM or similar.

thanks,

#64 PiotrM

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Posted 16 February 2013 - 09:44 PM

It's related to Micron/Aptina sensors. Firefly and QHY5 use them. The rings are caused by the sensor cover glass which can't be removed. ASI is also Micron based... but those cover-based artifacts don't show up in every sensor of given type.

#65 ourobouros2k2

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Posted 17 February 2013 - 01:08 AM

Thanks for the clarification, it looks like I will pass on that one for the time being. I know the rings are on the SSAG and thusly will be on the firefly as well then.

thank you!
Andy

#66 pippo

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Posted 17 February 2013 - 04:56 PM

Here an other image of Jupiter + Europe +Ganimede's shadow with the Firefly on the 15th of February.
Mak 703 at f/26 from Paris

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#67 pippo

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Posted 19 February 2013 - 02:49 AM

Jupiter + Io's Shadow + Io, from Paris with the Intes 703 at f/26 and the Firefly on the 18th of Feb 2013:

This with IR-cut filter at at 20:15 UT (21:15 local time)

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#68 pippo

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Posted 19 February 2013 - 03:33 AM

Jupiter + Io's Shadow + Io, from Paris with the Intes 703 at f/26 and the Firefly on the 18th of Feb 2013:

This without IR-cut filter at at 20:31 UT (21:31 local time).

The image with IR-cut filter is more resolved (the Airy disk is bigger in the IR) and with the IR-cut filter the red spot exhibits more contrast (it is darker).

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#69 pippo

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Posted 20 February 2013 - 03:01 AM

Yesterday the turbulence was minimal so I tried to push the focal length to f/35 (with a televue barlow 3x, Intes 703 mak 7", IRcutoff filter and obviously the Firefly MV).


Here is the result without rescaling:

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#70 pippo

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Posted 20 February 2013 - 03:07 AM

And here the same rescaled at 80% to compare with the f/26 images.

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