288 replies to this topic

[bvalente]

I have been taking new flats every time because I think my FW isn't putting the filters in exactly the same spot every time. It seems my vignetting is slightly different between filters. But it's been a few months, so I am just going off memory haha.  

Dan - did you ever figure this out?

 

I am looking into my scope and it appears the filters are slightly misaligned to the chip, i can see the filter frame is causing vignetting

 

Thanks Brian

[jayta98]

I wanted to thank Thirteen and the rest of the members for this thread. I got a 1st gen 1600MC from a fellow member. It has been a learning curve for me. Im still learning specially coming from dslr. I did noticed the camera performs well with planetary as well. How does it compare to the 224MC? The reason i ask is because i also have a 224mc that i had always used as planetary camera. I do use the 224mc for guiding but if the 1600 can perform the same or better than 224mc then maybe i could sell it and get a mono camera. I do know the 1600 has a bigger chip and utilizes more bandwidth. What are your thoughts about this?

[Thirteen]

I use the 1600 mono camera for planetary. I think it's a very passable planetary camera. It doesn't have the ultimate speed as some other choices, but does a good job. It's not going to be as good as the 224 for planetary. I don't think there is any doubt about that, especially if you are talking about the OSC version of the 1600. I think the 224 will beat it out on sensitivity and noise characteristics.

The advantage the 1600 has is monster chip size for planetary work. This makes capturing moon vistas or all the Galilean moons in one frame possible. So, it has its pros also.

[jayta98]

I use the 1600 mono camera for planetary. I think it's a very passable planetary camera. It doesn't have the ultimate speed as some other choices, but does a good job. It's not going to be as good as the 224 for planetary. I don't think there is any doubt about that, especially if you are talking about the OSC version of the 1600. I think the 224 will beat it out on sensitivity and noise characteristics.

The advantage the 1600 has is monster chip size for planetary work. This makes capturing moon vistas or all the Galilean moons in one frame possible. So, it has its pros also.

What is OSC version?

[gundark]

OSC stands for "one-shot color", as opposed to a mono camera. 

[pyrasanth]

Excellent job on the write up Jason. 

 

One thing that people are not really mentioning that much is the need to have a really nice processing computer in order to deal with the data and the potential for getting smaller durations and stacking.  I know I am going to build myself a super desktop in order to be able to handle the processing.  The issue is not the memory storage because memory is cheap.  I think that my systems are getting taxed by the need for processing speed. 

I faced this problem when using quite large data sets. A full set of images can quickly reach hundreds of Mb of data and that takes time to crunch.

 

I now use an Asus dual processor workstation board fitted with 2 Xeon E5-2630 CPU with 64 Gb of ECC RAM and a set of SSD drives. This has made the problem at least bearable on the processing time it takes.

 

Pixinsight has improved its registration & calibration processes and that again has really helped speed up the initial processing. I think fast multi-threading or multiple cpu processing is the way to go. I now crunch data with 24 threads and even that is now fairly low end but I don't see myself really needing to throw more processing at the task- I just wait a bit longer. 

[calan]

I love reading these in-depth threads where John, Jason, and others are throwing around ADU's and e's and 20xRN's and etc etc.... but by the end of the last page I feel like the dog on the Simpsons... just staring at what I've read in complete ignorance.  

Eventually I'm going to read enough of this stuff that it's going to click, and I'll know how to actually figure out the best gain and exposure time for any given night, rather than maybe stumbling blindly into something that seems to work.  lol

Edited by calan, 30 April 2017 - 05:52 AM.

[Thirteen]

Don't fret about it. There are some of us that are handed a rule of thumb and can't just accept it without knowing "why?".

But, it doesn't need to be complicated.

Gain - like ISO on a DSLR, ZWO offers presets in the ASCOM driver. Just pick one and start firing away. Unity gain is a good middle ground starting point.

Exposure - the 20x Read noise deal is all about keeping a high enough background level so that the background noise is not a problem. On the other hand you want to keep exposure low so as not to clip stars. So aiming for a mean value between 1000-2000 DN on a 16bit readout is a good place to start. You can generally go lower but that is a "safe" level.


Once you get a feel for it, you can optimize based on experience or dig into the math. You can easily use the camera effectively without the math.

Edited by Thirteen, 30 April 2017 - 07:30 AM.

[calan]

Don't fret about it. There are some of us that are handed a rule of thumb and can't just accept it without knowing "why?".

But, it doesn't need to be complicated.

Gain - like ISO on a DSLR, ZWO offers presets in the ASCOM driver. Just pick one and start firing away. Unity gain is a good middle ground starting point.

Exposure - the 20x Read noise deal is all about keeping a high enough background level so that the background noise is not a problem. On the other hand you want to keep exposure low so as not to clip stars. So aiming for a mean value between 1000-2000 DN on a 16bit readout is a good place to start. You can generally go lower but that is a "safe" level.


Once you get a feel for it, you can optimize based on experience or dig into the math. You can easily use the camera effectively without the math.

Thanks Jason. I've learned a ton over the years from you, John, Hiten, and others in your posts here, but still feel like I've just scratched the surface as far as imaging goes (which I have). 

I get it for the most part; there are just a few gaping holes in my knowledge that need to be filled in to make things easier. I'll get there!

[WConde]

And my 50 frame master luminance flat

 

Dust donut land …  the perils of an open manual filter wheel …

 

Master Flat Lum - 250 Frame Bias Subtracted_STF.jpg

 

This flat is using a manual filter wheel with the 1.25” luminance filter as close as possible to the camera.  It literally is less than .5mm from the front of the camera.  I know this due to an unfortunate rubbing sound before I shimmed it forward .5mm.    It is obvious that the extreme corners are vignetted from the filter.  But, it seemed to calibrate OK.

Hi Jason,

I recently purchased this camera.  Thanks for the detailed walk-through.  It has been very helpful!  What is the ADU that you use for your flats?

 

Thanks!

[Thirteen]

Enjoy! I try to hit 10k to 15k (16bit readout) for my flats. Seems to work for me.

[upnorth joe]

hi this is my first post and i'm a greenhorn I have a150mm starseeker scope and looking at the asi 1600 cool color camara and like to here form you also I live in northen Michigan the hummity gets hi shuod I gat the defog ring

[Thirteen]

Hello Joe, welcome! I have used the camera now for 1.5years and have never had an issue with the window digging. I have the first generation camera and now there are on releasing v4 with the “pro” model. The new ones do have some enhancements in place to prevent condensation. I would say you are going to be OK with out it. Worst case, you can buy and add it later if you find it to be a problem.

Edited by Thirteen, 25 October 2017 - 06:31 AM.

[upnorth joe]

I have one more question for anyone living with snow in the winter is there a filter that cuts or dlock reflection of the snow or dose the skyglow fliter work? thank you joe 

 

ps got my 1600mc yesterday