As we know all ASI cameras enable us small settings to adjust through ASCOM camera driver such as Gain and Offset. In this short article, we will show you a few test images of how cameras setting affects your captured image. For this test, we used ASI1600MM-Cool and ASI071MC-Cool, two very popular ZWO DSO cameras.
ASI ASCOM camera driver interface is very simple. In this case, we tested only predefined settings values for Gain and Offset. We have three options; highest dynamic range (G: 0 O: 10), unit gain (G: 139 O: 21) and lowest read noise (G: 300 O: 50). Which setting is the best for DSO imaging?
ASI1600 camera setting test
The first test we made with a 30-cm f4 telescope on G53F Friction Drive Mount was used, ASI1600MM-Cool and L filter. We point telescope on very popular target M1, the Crab Nebula in the constellation of Taurus. We captured three images with the highest dynamic range, unit gain, and lowest read noise settings. All three images were exposed 200-seconds at -20°C and bias, dark and flat not used. As we see lowest read noise settings give us very saturated images (stars and nebula). The reason for this is very low full well (bellow 1K) at this gain and offset values. Unit gain gives us a much better result. We have saturated only brighter/bigger stars. From our point of view, the best result gives us the highest dynamic range. Gain and offset values for this preset give us full well 20K. We got not saturated stars, good background patterns and also very good SNR. If we exposure too long the sky glow will cover the read noise and there is no big difference with low read noise (LRN) and high read noise (HDR) camera settings.
Short exposures with HDR and LRN camera settings on same objects give us much more interesting results. Both images were exposed 10 x 10-seconds at -20°C and bias, dark and flat not used. On this case we see LRN image have less noise and higher SNR.
Another test images were exposed 20 x 5-seconds at -20°C and bias, dark and flat not used. LRN image has less noise and higher SNR.
For the final test, we compared 1 x 1-seconds exposure image at -20°C and bias, dark and flat not used. The result is very similar. LRN image has less noise and higher SNR.
ASI071 camera setting test
We also made a test with a 135-mm f2.8 lens, ASI071MC-Cool and L filter (2″ IR-UV CUT ). We point telescope on a very popular Virgo Cluster (cluster of galaxies). Also in this test, we captured three images with the highest dynamic range, unit gain, and lowest read noise settings. All three images were exposed at 200-seconds at -20°C and bias, dark and flat not used. As we see lowest read noise settings give us very saturated stars, especially in R in G channel. At these values we have full well the only 3K. Unit gain has similar issues, but yes with lees saturated stars. Also in this test, we think the best result gives us the highest dynamic range with full well only 46K.
Short conclusion
Our visually conclusions are, highest HDR settings give better result at longer exposures. We have got not saturated stars, good SNR and also very good or same read noise pattern like images with LRN values. But if you preferred shorter exposures due your “lucky imaging technique” or mount track limit we prefer LRN settings.
Would LRN be the best to use for very faint objects like maybe Thor’s Helment?
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Yes, I think so.
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What I mean Sam is if I use the presets, will these adjust the Gain automatically or do I still need to adjust gain manually
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Usually, only use the automatical gain will be great for users. Thoes three gain settings is very typical.
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I have just got the ASI 1600 MM Pro
I noticed that in addition to the three settings (HDR, LRN and UG) there is a slider tho control the gain. I thought these settings would set the gain automatically. Do I also have to adjust the gain slider or do i just chose one of the three presets?
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You can adjust the gain slider manually as you wish.
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Thanks what I meant was, when I select one of the presets, does this automatically adjust the gain or do I still need to adjust the gain manually in addition to checking one of te pre sets. In other words, I assume that the HDR setting automatically adjusts the gain to 0 to enable a full well capacity, and the unity gain adjusts the gain to unity etc.. am I right ?
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When you select a preset and press set, program will auto adjust the gain.
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Thanks for posting this information. I find it very useful. I’m really impressed with my results with gain setting at zero. I’d like to try the LRN setting for galaxies at some point.
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You are welcome!
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Hi,
I just bought a 1600MM-Pro and noticed the driver doens’t include offset any more. Does this affect the way I should use the camera? If so, how?
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Hi Michael. Yes, we set a static value for offest, much easy for users. Because someone doesn’t understand offest and usually set a wrong value in photography.
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Thanks for the reply. In the test, you tried different combinations of gain and offset. Now the offset is fixed and hidden, would that affect the outcome of the test above or change the outcomes?
When should I use unity gain?
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A proper offset value won’t cause any problem
so just forget offset with these Pro cameras
you can use unity gain in most cases
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Hi Sam! I have the ASI294pro and i am looking for the right gain/exposure values…. it would be very helpfull to have a tool (short program) like this: https://youtu.be/97vUB-5HfVE. It would be very nice, to have this for each of your camera.
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we provide 3 predefined setting and you can choose any one of them
https://astronomy-imaging-camera.com/photography/cooled-asi-camera-setting-in-ascom-driver/
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I need a spacer / adapter ring which will allow attachment of the ASI 071 to a Takahashi 106 in the F5 configuration. The Takahashi has a 48mm female thread. The spacer ring needs to have a make 48mm male thread and have an inside female thread to accommodate a 2″ filter. Is such an adapter available from ZWO?
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I think you may have to make one
https://astronomy-imaging-camera.com/products/accessories/customize-adapter-for-zwo-products/
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Hola. En primer lugar felicitarte por este gran trabajo. Tengo la cámara 1600 mmc y no consigo que la temperatura funcione con el maxim dl 5 pro. Que tengo que hacer?. Con SGP funciona correctamente.
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MDL 5.23 and up fixed this problem
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Sam –
Compliments to ZWO – not only are you creating great products, but you guys “get it” when it comes to software, drivers, and supporting the customer.
I have used other cameras in the past, and am quickly becoming a ZWO Fan. I just bought the ASI 1600MC cooled and can’t wait to get out and use it.
Your manual/guide that came with the camera is excellent as are your posts to support it.
Well done and keep up the great work!
Dave
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thank you so much
we are keep moving with your guys’ support
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hola buen dia. ayer me llego la camara zwo1600 monocroma., tengo el cd de instalacion pero me dijeron que es mejor si busco en el fabricante la actualizacion y lo bajo de ahi.. como podria hacer?? o tengo que instalar todos los componentes del cd? o solo algunos. gracias si me pueden ayudar
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you can download from our site
that’s the newest
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Have just moved across to mono camera from DSLR, and purchased from FLO in the UK, the bundle 2 kit with 31mm filters for f4/f5 Newtonians.
Obviously lots to learn, and I am currently setting up my Dark and Bias libraries.
This is an excellent article, and really opens my eyes to Gain/exposure choices.
Many thanks for this guide, and many thanks for changing my reality, with this excellent camera.
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Hoping you will have fun in DSO imaging!
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Hi Sam
This ‘instruction’ article is highly informative and very valuable for folks like me just setting up my 1600MC. More like this please!!!
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Thanks for this information, Sam.
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would the same exposure settings apply to the asi 1600 color, for the 10,5 and 1 second exposures ???
when using the astrolive software for mac, I only see the option to adjust gain, what offset is it using at gain 300 and is it adjustable ?
thx for posting this….
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you don’t need to adjust offset for live stacking
you need to use high gain for short exposure
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Thank you for this write up. Could you please clarify if these images are linear or streched in any way?
Thank you!
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Hi, thanks for sharing this kind of official evidence.
I am a user of a non-cooled asi178mc and I would like to know the correct values for long exposures (HDR) and shorter exposures with the “LRN” image technique in order to take advantage of my configuration.
Thank you
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just choose it in the ASCOM
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Thanks for sharing this “official” article. It’s good to read ZWO opinions in this matter.
Thans again. Best wishes,
Aleix Roig
PRADES, Tarragona (Catalunya-Spain)
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we will do more like this in the future
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This is all new to me so please forgive my newbie questions:
Can you explain the settings to me? In other words what is “gain” vs “offset”?
If I make “gain” adjustments in software capture program like Sharp Capture… I assume it is using the ASCOM driver to make those adjustments correct? I don’t have to make adjustments to the driver AND the software capture program.
Thank you
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gain and offset both are parameters for sensor
and there is no relationship between ASCOM and software like SharpCap
I suggest you can have a look at our software manual
https://astronomy-imaging-camera.com/manuals/ASICameras-software-Manual-Windows-EN.pdf
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I like the flexibility of Asi1600mm-c , It’s really game changer, I started using my own two week ago , usually I do unity gain with narrowband & It yeld good results at shorter exposures , I’m still learning & I will try LRN & HDR as i got clear sky
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thanks just try it
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