ZWO ASI 533MM-Pro Cooled Mono Camera

[Hans Joakim]

Actually, I think the Uranus-C is a very nice camera for the RASA:

 

Similarly for relatively short focal length refractors; I ordered one for my 3-in 480mm apo.

[Adam J]

1 hour ago, Hans Joakim said:

Actually, I think the Uranus-C is a very nice camera for the RASA:

 

Similarly for relatively short focal length refractors; I ordered one for my 3-in 480mm apo.

You might be right in the case of an OSC. Spot size on the RASA 8 is a minimum of 3um in green but quite allot larger in Red as would be for HA and Blue. I strongly suspect that you would still be seeing limited most of the time at 1.5um sampling though. I do notice that my Esprit 100 images look significantly sharper than what i tend to see posted from a RASA 8.

Either way its possible to over think such things, the result speaks for itself. 

Adam  

[900SL]

21 hours ago, FLO said:

I see where you are coming from, modern sensors are less dependent on cooling, but demand for cooled cameras remains significantly higher than uncooled. 

HTH, 

Steve 

Particularly here in Saudi  

[vlaiv]

2 hours ago, Hans Joakim said:

Actually, I think the Uranus-C is a very nice camera for the RASA:

No, RASA does not have diffraction limited optics and you really want between 4 and 5 um pixel size for it to properly sample its images.

In above spot diagram, you can see that sharpest part is 550nm in center - and it has spot diagram of 3.6um.

Add seeing and mount tracking to that and you'll easily have FWHM of say 4" in RASA8 images - and that corresponds to about 2.5"/px or ~4.85um pixel size.

[Adam J]

1 hour ago, vlaiv said:

No, RASA does not have diffraction limited optics and you really want between 4 and 5 um pixel size for it to properly sample its images.

In above spot diagram, you can see that sharpest part is 550nm in center - and it has spot diagram of 3.6um.

Add seeing and mount tracking to that and you'll easily have FWHM of say 4" in RASA8 images - and that corresponds to about 2.5"/px or ~4.85um pixel size.

But as the camera is an OSC do we not effectively consider it as sampling (by your reckoning) x2 the pixel size? If so that would make the effective pixel size 5.8um? That being the biggest problem with the suitability calculator?

Adam

[vlaiv]

41 minutes ago, Adam J said:

But as the camera is an OSC do we not effectively consider it as sampling (by your reckoning) x2 the pixel size? If so that would make the effective pixel size 5.8um? That being the biggest problem with the suitability calculator?

Adam

We do - almost no one is using OSC at x2 pixel size.

It really does not matter in this case, I just wanted to point out that RASA8 is in no way capable of producing 1.5"/px image at that actual resolution.

That is something we often don't consider - spot diagrams.

I've seen some telescopes that come with RMS figures for their spot diagrams and that is probably the best we can do in determining possible resolution of the system (combined with guiding RMS and seeing FWHM).

[tomato]

Uncooled versions of the latest CMOS cameras do make technical sense but that has to overcome the manufacturer’s commercial intent. I doubt it costs ZWO £400 to fit a Peltier cooler to the camera so it’s in their interest to keep pushing them out. Cars don’t really need electric windows, reversing cameras or even alloy wheels, but that’s what the majority of customers want and will pay for them.

I believe the latest Dyson vacuum cleaner will give you a dynamic bar chart of the dust particle size distribution that it is collecting, every time I hoover the house I wish I had one of those.☺️

[FLO]

I understand ZWO's decision to include a proper cooler.

The camera is designed for today's market. A market in which the majority of astronomers want a cooled camera. Will tomorrow's astronomers still want cooling? Perhaps not. But that is then and this is now. 

Steve

[scotty38]

11 hours ago, tomato said:

I believe the latest Dyson vacuum cleaner will give you a dynamic bar chart of the dust particle size distribution that it is collecting, every time I Dyson the house I wish I had one of those.☺️

Fixed that for you 🤣🤣🤣

[FLO]

11 hours ago, tomato said:

... every time I hoover the house I wish I had one of those.☺️

 

29 minutes ago, scotty38 said:

Fixed that for you 🤣🤣🤣

James M. Spangler invented the first commercially successful vacuum cleaner and was awarded the patent.  William H. Hoover was so impressed he purchased Spangler's company and patent. 

So, strictly speaking, we 'spangle' the carpet 😁

... I'll get my coat. 

Steve

[Craney]

9 minutes ago, FLO said:

So, strictly speaking, we 'spangle' the carpet 😁

 

If I had 'spangled' the carpet as a kid, I would have got a clip around the ear......  and made to Hoover it !!!

[jacko61]

18 minutes ago, Craney said:

 

If I had 'spangled' the carpet as a kid, I would have got a clip around the ear......  and made to Hoover it !!!

Things I wish we still had.

Graeme

[tomato]

1 hour ago, scotty38 said:

Fixed that for you 🤣🤣🤣

I actually use a Dyson but it’s one of those terribly dated mains powered models. Funny though, the trailing lead never seems to bother me as much as the darn thing running out of juice before I’ve finished.