asi183 Move from DSLR to a dedicated CMOS camera..

[etunar]

I have been doing this for many years using  a star adventurer with a canon 6d  and different lenses upto 200mm from dark sky locations.

I wanted to get proper scope and EQ mount for a while but I didn’t think it was worth it shooting from the cloudy UK and I didn’t realise bortle 5 skies were good enough for it. After realising I was wrong I bought a HEQ5 and WO zs61. (I wanted a relatively small scope to begin with). 
 

next thing I want to get is a dedicated astro camera. And of course going mono makes the most sense. Coming from a landscape photography world, bigger sensor is always better. However this is where I get lost a bit. According to the ccd calculator on astronomy tools website asi183mm pro is the best match for my scope (1.38 arc sec / pixel). Next option would be asi1600mm pro with a resolution of 2.18arc sec / pixel. However I’m slightly worried about this microlensing/reflection issue. Using a relatively wide scope, I may not be able to avoid bright stars all the time. And I know it would bug me if it happened.

i know zwo released new cameras recently but asi6200 is way out of my budget. 
 

I can probably justify the cost of asi2600 (also 2.15 arc sec/pixel) . I know it’s an OSC and not mono, but the specs seem promising and I know few people mentioned the possibility of using this with narrowband filters. It’s still a relatively new camera so not a whole lot of information on it unfortunately but everyone who had one seems to like it. It would be interesting to compare this setup with a asi1600 for example. 
 

- So is the asi183 really the best choice? Or slight under sampling is not an issue?

- asi1600 vs asi2600? 
 

- I assume it’s still a big jump to go from a full frame dslr to a set point cooled OSC with a smaller sensor? 

[endless-sky]

Even if you would be slightly undersampled, you could use dithering (which also benefits to reduce noise) and then drizzle integration (if you use PixInsight) which basically doubles your resolution.

Coming from a full frame, what would worry me is also the field of view (how much or how little of the frame the object you are trying to capture would take up).

Lastly, I would definitely go with monochrome. I won't go into much details, as I don't want to start a war between mono and color, but from what I read the mono version of the same camera model is pretty much always better. Plus you can do narrow band more efficiently.

Good luck with your choice and clear skies!

[MartinB]

There is so much to think about and some of the questions you are posing will generate conflicting views!  If you are prepared to fund the additional cost of a motorised filter wheel and filters then my personal view is that mono is a more effective and flexible way to image.  That opinion is based not just on theory but also practical experience of using both types of camera.  

With regard to pixel size and sampling rate, my experience is that my seeing conditions rarely let me get close to the theoretical sampling rate of my ASI 1600.  Obviously seeing is site dependent but on good deep sky imaging nights, with a  transparent sky my stars are twinkling! I think the optimum sampling rates people bandy about are ideal for cloud cuckoo land!  I have been absolutely delighted with my ASI 1600 and use it with a 200mm lens and a Tak FSQ106.  Here is an example with the 200mm lens (sampling rate 3.92 arc secs/ pixel) 

I think a ZS61 and an ASI 1600 MM Pro would be an outstanding combination.  

[ollypenrice]

^^ Sound as a pound. Let's not forget how many APODS and Pictures of the Day have been shot with the Kodak 11 meg and Tak 106 at 3.5 arcseconds per pixel.

Olly

[etunar]

7 hours ago, endlessky said:

Even if you would be slightly undersampled, you could use dithering (which also benefits to reduce noise) and then drizzle integration (if you use PixInsight) which basically doubles your resolution.

Coming from a full frame, what would worry me is also the field of view (how much or how little of the frame the object you are trying to capture would take up).

Lastly, I would definitely go with monochrome. I won't go into much details, as I don't want to start a war between mono and color, but from what I read the mono version of the same camera model is pretty much always better. Plus you can do narrow band more efficiently.

Good luck with your choice and clear skies!

I checked the field of view on astronomy tools website - I think the smaller field of view can actually be a bonus with extra reach - although until I try I will never know.

I am definitely not afraid of monochrome, it's just the some of the common problems of the panasonic sensor on asi1600 - although it may be a case of you hear the problems more than the positive feedback. And also how does 4-5 year old 12 bit monochrome sensor compare with a newer 16 bit colour sensor.

 

6 hours ago, MartinB said:

There is so much to think about and some of the questions you are posing will generate conflicting views!  If you are prepared to fund the additional cost of a motorised filter wheel and filters then my personal view is that mono is a more effective and flexible way to image.  That opinion is based not just on theory but also practical experience of using both types of camera.  

With regard to pixel size and sampling rate, my experience is that my seeing conditions rarely let me get close to the theoretical sampling rate of my ASI 1600.  Obviously seeing is site dependent but on good deep sky imaging nights, with a  transparent sky my stars are twinkling! I think the optimum sampling rates people bandy about are ideal for cloud cuckoo land!  I have been absolutely delighted with my ASI 1600 and use it with a 200mm lens and a Tak FSQ106.  Here is an example with the 200mm lens (sampling rate 3.92 arc secs/ pixel) 

I think a ZS61 and an ASI 1600 MM Pro would be an outstanding combination.  

I think the cost of 1600mm pro with filter wheel and filters (not astrodon/chroma) is roughly the same as asi2600, so the costs work out similar in that aspect.

edit: oh and that's a stunning image btw. I'm always amazed what you can photograph at such a wide angle.

Edited June 26, 2020 by etunar

[RichardHurst]

Hi Mate, This is a question I've been trying to answer myself and to be honest I still can't decide to go Mono or OSC. I'm not sure we get enough clear nights here in the UK for me to have the patience of going Mono but I'm still deciding 

[etunar]

On 03/07/2020 at 13:29, RichardHurst said:

Hi Mate, This is a question I've been trying to answer myself and to be honest I still can't decide to go Mono or OSC. I'm not sure we get enough clear nights here in the UK for me to have the patience of going Mono but I'm still deciding 

indeed. Everytime I read about cameras I change my mind.

[Stub Mandrel]

I agonised for over a year.

I don't regret going for the ASI1600MM.

 

[DaveS]

This is one I did back in May-June, 24 hours in total mostly under Nautical Dark using the SHO palette.

This could NOT have been done in OSC.

[MartinB]

On 03/07/2020 at 13:29, RichardHurst said:

Hi Mate, This is a question I've been trying to answer myself and to be honest I still can't decide to go Mono or OSC. I'm not sure we get enough clear nights here in the UK for me to have the patience of going Mono but I'm still deciding 

In my experience, having done a fair bit of imaging with both types of camera, mono cameras gather data more effeciently (require less time to achieve a given SNR), and are more flexible than osc.  The main issue is one of expence.   

[etunar]

4 hours ago, MartinB said:

In my experience, having done a fair bit of imaging with both types of camera, mono cameras gather data more effeciently (require less time to achieve a given SNR), and are more flexible than osc.  The main issue is one of expence.   

I do get that if you have the same sensor in mono vs osc, mono will be more efficient/faster. What makes my decision difficult is how does a 4-5 year old sensor from asi1600 compare with the newer technology sensor from asi2600 with higher QE, larger well depth, 16 bit etc..  cost wise the initial outlay is roughly the same between the two (I'm ignoring astrodon/chroma filters for the time being).

 

[david_taurus83]

Have you considered a KAF8300? If I was in the market now for a mono setup and a sensor of similar size to the ASI1600 I'd gladly snap up one of these old CCD's. Check out Adams pics @tooth_dr

 

[etunar]

2 hours ago, david_taurus83 said:

Have you considered a KAF8300? If I was in the market now for a mono setup and a sensor of similar size to the ASI1600 I'd gladly snap up one of these old CCD's. Check out Adams pics @tooth_dr

 

I thought about CCD, but I was a bit intimidated by very long exposure times (20-30min) people tend to use for subs.

[david_taurus83]

7 minutes ago, etunar said:

I thought about CCD, but I was a bit intimidated by very long exposure times (20-30min) people tend to use for subs.

I used to shoot 900s Ha subs with my ASI1600 at unity gain so there's not much difference. I found this gave better cleaner results than say 300s subs with higher gain. Personally I prefer to shoot as long a sub as possible than say, lots of short ones. Its a pain to preprocess 1200 x 30s subs, trust me!

[etunar]

3 minutes ago, david_taurus83 said:

I used to shoot 900s Ha subs with my ASI1600 at unity gain so there's not much difference. I found this gave better cleaner results than say 300s subs with higher gain. Personally I prefer to shoot as long a sub as possible than say, lots of short ones. Its a pain to preprocess 1200 x 30s subs, trust me!

oh definitely.  I dont like doing short subs at all. too many files to manage as well. How come you have gone back to a 6D after asi1600 if you don't mind me asking?

[david_taurus83]

I processed some data someone took with a 6D and I was pleasantly surprised with how little noise it showed compared to my old 600D. So I had a grand idea and I bought a 6D with the intention of shooting RGB and mono at the same time with a dual rig. I got a bit carried away tbh lol.

The ASI1600 was great for narrowband. But I got a bit frustrated with LRGB as I could only ever seem to grab a few hours on one filter and then had to wait weeks for another filter. Maybe it was just bad luck with the weather. In the end I sold most of my gear and went with a small portable setup with the 6D. Built up again and just recently sold all again lol. Currently holding onto the 6D, 135mm F2 lens and a CEM25P.

I have this awful habit of slimming gear down to acceptable levels and watch as it mysteriously grows exponentially again over 6 months..🤔

 

[etunar]

13 hours ago, david_taurus83 said:

I processed some data someone took with a 6D and I was pleasantly surprised with how little noise it showed compared to my old 600D. So I had a grand idea and I bought a 6D with the intention of shooting RGB and mono at the same time with a dual rig. I got a bit carried away tbh lol.

The ASI1600 was great for narrowband. But I got a bit frustrated with LRGB as I could only ever seem to grab a few hours on one filter and then had to wait weeks for another filter. Maybe it was just bad luck with the weather. In the end I sold most of my gear and went with a small portable setup with the 6D. Built up again and just recently sold all again lol. Currently holding onto the 6D, 135mm F2 lens and a CEM25P.

I have this awful habit of slimming gear down to acceptable levels and watch as it mysteriously grows exponentially again over 6 months..🤔

 

Haha. I can relate to that. I love my combo of 6D, 135mm and star adventurer combo. It's a perfect travel setup i think with no laptops etc.. This is also one of the reasons why I'm more hesistant about buying an OSC - while it will definitely be an improvement over 6D, I am chuffed with what I can get from dark sky locations with it.

[MartinB]

17 hours ago, etunar said:

I do get that if you have the same sensor in mono vs osc, mono will be more efficient/faster. What makes my decision difficult is how does a 4-5 year old sensor from asi1600 compare with the newer technology sensor from asi2600 with higher QE, larger well depth, 16 bit etc..  cost wise the initial outlay is roughly the same between the two (I'm ignoring astrodon/chroma filters for the time being).

 

Well, I am currently considering getting another camera set up for my observatory to use with my Tak fsq.  It will almost certainly e anASI 1600mm.  If the asi2600 was available in mono I would definitely consider it, but no way will I go back to Osc.

Regarding exposure times the choice is yours!  I have been very satisfied with 300 sec subs for NB and my data indicates that, with my sky, I am above read noise threshold.  I might change to 600 secs because the large number of subs can be a pain (with simeis-147 I had 31 hours worth to contend with!).  With my ccd I need 30 min (1 hour would probably be better still) and this is a real pain, any wisp of cloud destroys the sub.  My ccd camera has a very high QE and, of course is 16bit, but none of this seems to make any difference when it comes to real world data, the asi is the better performer.  The main advantage of ccd is that you can do "proper" binning and use bias frames during calibration.  Being able to bin colour data when lrgb imaging at longer focal lengths is a big plus for ccd.