ZWO/Player One IMX 585 Sensor Image Showcase

[PeterC65]

2 hours ago, Trippelforge said:

 

I have been digging into spectrum ranges due to learning that modified DSLRs list out various options. I also noticed the IMX585 seems to cut off prior to falling into the UV range (via it's website graph). Another user in a post said:

 I don't see anything in the player one listing directly addressing that question. Any idea on the answer if the question is important?

Both the Player One and the ZWO cameras have AR coated windows meaning they let through all wavelengths. They both use the IMX585 sensor so I would expect their QE curves (wavelength response curves) to be identical, but the camera specs show some small differences which may be caused by different window materials.

QE curves differ mostly from sensor to sensor and those for the IMX585 are fairly typical.

Neither Player One nor ZWO seem to specify QE below 400nm, so in the UV band, but they are both sensitive in the IR band. At 400nm the blue response is falling but the red and green responses are rising so without a spec it is hard to know what the UV response will be. Have you seen something that specifies the response below 400nm? I'd be interested to know what it might be.

I've recently bought an Astronomik L2 filter to cut the IR band. I've yet to try it but expect it to reduce star bloat. I also have an IR pass filter, also yet to be tried, as I understand that IR imaging of the Moon and planets can reduce atmospheric distortion.

 

[Trippelforge]

12 minutes ago, PeterC65 said:

Both the Player One and the ZWO cameras have AR coated windows meaning they let through all wavelengths. They both use the IMX585 sensor so I would expect their QE curves (wavelength response curves) to be identical, but the camera specs show some small differences which may be caused by different window materials.

QE curves differ mostly from sensor to sensor and those for the IMX585 are fairly typical.

Neither Player One nor ZWO seem to specify QE below 400nm, so in the UV band, but they are both sensitive in the IR band. At 400nm the blue response is falling but the red and green responses are rising so without a spec it is hard to know what the UV response will be. Have you seen something that specifies the response below 400nm? I'd be interested to know what it might be.

I've recently bought an Astronomik L2 filter to cut the IR band. I've yet to try it but expect it to reduce star bloat. I also have an IR pass filter, also yet to be tried, as I understand that IR imaging of the Moon and planets can reduce atmospheric distortion.

 

I just looked at their posted graph and noticed that's where it stopped. I did notice as you said that the red and green were still rising when they had hit the 400 limit though. But I obviously don't really know how that works (figured it was a cut off point). When imaging DSO's what is the reasoning behind blocking the IR band? Is it just not needed for certain targets / causes actually degradation of final images? 

[happy-kat]

I have a very sensitive IR camera and if I don't block IR, focus is not as good. If I want IR then I change filter and block everything else.

Edit: to clarify this is my findings with a ZWO462MC

Edited November 10, 2022 by happy-kat

[Trippelforge]

21 minutes ago, happy-kat said:

I have a very sensitive IR camera and if I don't block IR, focus is not as good. If I want IR then I change filter and block everything else.

Thank you that clears it up. Do you have the IMX585 chip? I am now curious if it would have focus issues without a filter. 

[happy-kat]

I'm interested in following this camera but I've edited my comment to clarify that I'd referenced a different camera with just an AR window. 

[PeterC65]

3 hours ago, Trippelforge said:

I just looked at their posted graph and noticed that's where it stopped. I did notice as you said that the red and green were still rising when they had hit the 400 limit though. But I obviously don't really know how that works (figured it was a cut off point). When imaging DSO's what is the reasoning behind blocking the IR band? Is it just not needed for certain targets / causes actually degradation of final images? 

I'm still figuring this stuff out myself, but as I understand it, with refractor telescopes the focus position depends on the wavelength of the light and the wider the range of wavelengths the wider the focus range. So when using a camera, which is sensitive across a wider range of wavelengths than the eye, the lack of focus at extremes of wavelength can be noticeable. A UV / IR cut filter limits the range of wavelengths thereby limiting the extent of chromatic aberration and star bloat. Personally, I haven't noticed star bloat so far, and I've not been using a filter. I've bought the L2 filter to check how much difference it makes. There is a case for not cutting the IR since it is more light which usually improves the image, provided it is in focus.

[Trippelforge]

11 minutes ago, PeterC65 said:

I'm still figuring this stuff out myself, but as I understand it, with refractor telescopes the focus position depends on the wavelength of the light and the wider the range of wavelengths the wider the focus range. So when using a camera, which is sensitive across a wider range of wavelengths than the eye, the lack of focus at extremes of wavelength can be noticeable. A UV / IR cut filter limits the range of wavelengths thereby limiting the extent of chromatic aberration and star bloat. Personally, I haven't noticed star bloat so far, and I've not been using a filter. I've bought the L2 filter to check how much difference it makes. There is a case for not cutting the IR since it is more light which usually improves the image, provided it is in focus.

Thank you for explaining that, it makes sense. Quick question, how do people focus in on a particular wavelength? With just starting out my only association with focusing is simply using a bright star. 

So in your final opinion the Uranus - C hasn't been a bad camera? I planned on using it as a budget DSO for now. My stupid 500D has been having some sketchy problems. But so many people in the other forums keep trashing them and pushing me to start out without something at the 1k price point. I can't afford that though. lol

[PeterC65]

3 hours ago, Trippelforge said:

Thank you for explaining that, it makes sense. Quick question, how do people focus in on a particular wavelength? With just starting out my only association with focusing is simply using a bright star. 

So in your final opinion the Uranus - C hasn't been a bad camera? I planned on using it as a budget DSO for now. My stupid 500D has been having some sketchy problems. But so many people in the other forums keep trashing them and pushing me to start out without something at the 1k price point. I can't afford that though. lol

Bear in mind that I'm fairly new to astronomy but ...

You can use narrow band filters to select a particular wavelength and image only that one. This is how people use monochrome cameras I believe, using red green and blue filters to pick out those parts of the spectrum and sometimes narrow band filters to pick out particular emission lines. The seperate images then get combined, sometimes with false colour, in post processing.

You can use narrow band filters with colour cameras too to pick out the emission lines from a nebula for example. This is what I do with a UHC filter and an OIII filter.

Whatever range of wavelength you are collecting, the optimum focus point will be an average. Whether you can see blur in the imaged object will depend on the range of wavelengths being emitted and observed, and the degree of chromatic aberration in your scope. I've not found this to be a problem so far with no filter but a fairly nice refractor (an apocromatic with FPL53 glass).

I'm very happy with the Uranus-C. I would have probably felt the same about the ASI585. I'm glad I didn't go for an even bigger sensor as I think there would have been illumination issues and unless you pay four times the price there is nothing with such a low read noise. The next step up would be the IMX533 sensor, so the Saturn-C or ASI533, but the IMX533 sensor is only wider than the IMX585 in one dimension and not worth the extra cash I believe. Cooled cameras may be better for full on astrophotography with long exposures but they are much more expensive and I think it is diminishing returns.

I should add that I do EEVA and only take snapshots so I'm not after the n'th degree of perfection.

Edited November 10, 2022 by PeterC65

[Trippelforge]

15 hours ago, PeterC65 said:

Bear in mind that I'm fairly new to astronomy but ...

You can use narrow band filters to select a particular wavelength and image only that one. This is how people use monochrome cameras I believe, using red green and blue filters to pick out those parts of the spectrum and sometimes narrow band filters to pick out particular emission lines. The seperate images then get combined, sometimes with false colour, in post processing.

You can use narrow band filters with colour cameras too to pick out the emission lines from a nebula for example. This is what I do with a UHC filter and an OIII filter.

Whatever range of wavelength you are collecting, the optimum focus point will be an average. Whether you can see blur in the imaged object will depend on the range of wavelengths being emitted and observed, and the degree of chromatic aberration in your scope. I've not found this to be a problem so far with no filter but a fairly nice refractor (an apocromatic with FPL53 glass).

I'm very happy with the Uranus-C. I would have probably felt the same about the ASI585. I'm glad I didn't go for an even bigger sensor as I think there would have been illumination issues and unless you pay four times the price there is nothing with such a low read noise. The next step up would be the IMX533 sensor, so the Saturn-C or ASI533, but the IMX533 sensor is only wider than the IMX585 in one dimension and not worth the extra cash I believe. Cooled cameras may be better for full on astrophotography with long exposures but they are much more expensive and I think it is diminishing returns.

I should add that I do EEVA and only take snapshots so I'm not after the n'th degree of perfection.

 

What does EEVA mean?

Thanks for explaining everything to me, I feel much more educated on the topic now. My main issue at this point is worrying about the FOV. I had no idea how small the Uranus-C was FOV wise until this morning when using the tool. So I have gone out now and started to research focal reducers to see if I can open that up a bit. 

 

[PeterC65]

1 minute ago, Trippelforge said:

 

What does EEVA mean?

Thanks for explaining everything to me, I feel much more educated on the topic now. My main issue at this point is worrying about the FOV. I had no idea how small the Uranus-C was FOV wise until this morning when using the tool. So I have gone out now and started to research focal reducers to see if I can open that up a bit. 

 

EEVA is Electronically Enhanced Visual Astronomy. It's sometimes called EAA, Electronically Assisted Astronomy. Another (older) name for it is Video Astronomy.

Basically, it means using a camera instead of an eyepiece but viewing the image live, or close to live. I think the older term Video Astronomy means live, whereas today it is possible to do live stacking, so the images are processed but close to live. By "close to live" I mean anything from sitting in front of the laptop watching as the 4s exposure frames arrive and are stacked (this is what I mostly do) through to letting the software stack frames for 15 minutes and then taking a look.

What EEVA isn't is collecting data for hours, sometimes over multiple sessions, then post processing it much later. That is AP, Astro Photography, which is my opinion is a different hobby. EEVA is much closer to visual only astronomy (just using your own eyes).

I've just read your other post about how useful more stacking can be, and I think you should decide whether you want results on the night (EEVA) or the next day (AP). The kit you need for each is quite a bit different (AP is more expensive!).

I like a wide field of view when I observe visually. The first astro camera I used for EEVA had a 5.6mm x 3.1mm sensor and this felt like I was looking through a keyhole compared with the DSLR that I also used (22.2mm x 14.7mm). The DSLR is a pain in the neck (too big, too heavy, has a physical shutter, only runs off its own batteries) so I wanted an astro camera with a sensor about the same size as the DSLR. At that size they have relatively high read noise and are expensive for the better ones and that's why I settled on the mid-sized Uranus-C (11.2mm x 6.3mm). It's field of view is double that of my first camera but half that of the DSLR. So, I also have a x0.6 Reducer / Field Flattener which solves the problem. I've only used it once so far but it produced a great view of M31 (I posted a snapshot in this thread, page 6 about 1/3 of the way down, on October 21). Focal Reducers only really work with refractors though (I believe - mine certainly doesn't work with my Newtonian).

Since I bought the Uranus-C I've also realised that the bigger the sensor the more area the scope needs to illuminate. Some scopes struggle to illuminate a full DSLR sensor, and you get darker corners in the image (vignetting), plus the scopes inherent edge deficiencies (aberrations of various types) are worse the further out from the centre of the illumination. If you think about it, most scopes are designed for visual use where at most they have to illuminate a 7mm diameter human eye, so asking them to illuminate and remain in focus across a 27mm diagonal DSLR sensor is pushing things.

[Ratlet]

5 hours ago, PeterC65 said:

EEVA is Electronically Enhanced Visual Astronomy. It's sometimes called EAA, Electronically Assisted Astronomy. Another (older) name for it is Video Astronomy.

Basically, it means using a camera instead of an eyepiece but viewing the image live, or close to live. I think the older term Video Astronomy means live, whereas today it is possible to do live stacking, so the images are processed but close to live. By "close to live" I mean anything from sitting in front of the laptop watching as the 4s exposure frames arrive and are stacked (this is what I mostly do) through to letting the software stack frames for 15 minutes and then taking a look.

What EEVA isn't is collecting data for hours, sometimes over multiple sessions, then post processing it much later. That is AP, Astro Photography, which is my opinion is a different hobby. EEVA is much closer to visual only astronomy (just using your own eyes).

I've just read your other post about how useful more stacking can be, and I think you should decide whether you want results on the night (EEVA) or the next day (AP). The kit you need for each is quite a bit different (AP is more expensive!).

I like a wide field of view when I observe visually. The first astro camera I used for EEVA had a 5.6mm x 3.1mm sensor and this felt like I was looking through a keyhole compared with the DSLR that I also used (22.2mm x 14.7mm). The DSLR is a pain in the neck (too big, too heavy, has a physical shutter, only runs off its own batteries) so I wanted an astro camera with a sensor about the same size as the DSLR. At that size they have relatively high read noise and are expensive for the better ones and that's why I settled on the mid-sized Uranus-C (11.2mm x 6.3mm). It's field of view is double that of my first camera but half that of the DSLR. So, I also have a x0.6 Reducer / Field Flattener which solves the problem. I've only used it once so far but it produced a great view of M31 (I posted a snapshot in this thread, page 6 about 1/3 of the way down, on October 21). Focal Reducers only really work with refractors though (I believe - mine certainly doesn't work with my Newtonian).

Since I bought the Uranus-C I've also realised that the bigger the sensor the more area the scope needs to illuminate. Some scopes struggle to illuminate a full DSLR sensor, and you get darker corners in the image (vignetting), plus the scopes inherent edge deficiencies (aberrations of various types) are worse the further out from the centre of the illumination. If you think about it, most scopes are designed for visual use where at most they have to illuminate a 7mm diameter human eye, so asking them to illuminate and remain in focus across a 27mm diagonal DSLR sensor is pushing things.

This is why sensors of this size are weapons imho.  You crop out the rubbish edges by default.  Get up and running with imagin on a newt and save £200 on a coma corrector and no fight with tilt and back spacing and the slow loss of the will to live?  Magic.

[MichaelBibby]

Can I use the Uranus-C as a guide camera with PHD2? Can anyone see any reasons why not? I just checked and the camera connects okay to PHD2, so I can't see any reason why not. I'm sure its sensitive enough too, and the small pixel size makes it ideal for that application (on a guidescope at focal length of 190mm, F4). If the weather wasn't so bad here I could try and see for myself but I am growing impatient of waiting to find out...

Also, would there be any problems with using two Uranus-c on one computer: one for guiding with PHD2 and one for imaging with Sharpcap? Might this itself create a problem?

Edit: there is no option for me to adjust the gain settings in the camera settings tab. I've downloaded the Ascom driver for my camera. Any ideas whats going on there? Is the camera not fully supported?

 

Edited November 14, 2022 by MichaelBibby

[bottletopburly]

In phd2 next to the box where you connect camera if you press that before connecting that brings up the driver if my memory serves me correct.

[Dark Raven]

4 hours ago, MichaelBibby said:

Can I use the Uranus-C as a guide camera with PHD2? Can anyone see any reasons why not?

Although certainly possible, the PH2 author recommends that mono camera be used for guiding. 

You can find his presentations on YT by searching for "bruce waddington phd2"

[MichaelBibby]

3 minutes ago, Dark Raven said:

Although certainly possible, the PH2 author recommends that mono camera be used for guiding. 

You can find his presentations on YT by searching for "bruce waddington phd2"

As I understand it the lack of sensitivity is the main issue of using colour camera's, as compared to mono camera's, for guiding, but many OSC these days are very sensitive, so maybe that conventional wisdom no longer applies?

[Dark Raven]

Maybe not cost-effective, but certainly doable. Especially with short focal lengths where you have a large field of view and rich starfield. With a long focal length and Off-Axis Guiding that sensitivity difference might play a crucial difference.

There is a "new" train of thought that guiding is becoming redundant altogether.

 

[MichaelBibby]

16 minutes ago, Dark Raven said:

Maybe not cost-effective, but certainly doable. Especially with short focal lengths where you have a large field of view and rich starfield. With a long focal length and Off-Axis Guiding that sensitivity difference might play a crucial difference.

There is a "new" train of thought that guiding is becoming redundant altogether.

 

Yes, thats what I was basically testing with my current setup: what can be done achieved using a sensitive, low noise OSC and reasonably fast optics (F5) without guiding. I've been pretty happy with the results, but of course, I suffer from the same obsessive neurosis as pretty much everyone else here and so have quickly moved on to guiding. In the future, I would like to get a 8" Quattro with a focal reducer to image at about 3.5 or so and really pull the light in (not interested in the ultra fast RASA 8, I like my Newtonians! and I probably wont be able to afford a SCT with a hyperstar anytime soon).

[Trippelforge]

On 11/11/2022 at 09:28, PeterC65 said:

EEVA is Electronically Enhanced Visual Astronomy. It's sometimes called EAA, Electronically Assisted Astronomy. Another (older) name for it is Video Astronomy.

Basically, it means using a camera instead of an eyepiece but viewing the image live, or close to live. I think the older term Video Astronomy means live, whereas today it is possible to do live stacking, so the images are processed but close to live. By "close to live" I mean anything from sitting in front of the laptop watching as the 4s exposure frames arrive and are stacked (this is what I mostly do) through to letting the software stack frames for 15 minutes and then taking a look.

What EEVA isn't is collecting data for hours, sometimes over multiple sessions, then post processing it much later. That is AP, Astro Photography, which is my opinion is a different hobby. EEVA is much closer to visual only astronomy (just using your own eyes).

I've just read your other post about how useful more stacking can be, and I think you should decide whether you want results on the night (EEVA) or the next day (AP). The kit you need for each is quite a bit different (AP is more expensive!).

I like a wide field of view when I observe visually. The first astro camera I used for EEVA had a 5.6mm x 3.1mm sensor and this felt like I was looking through a keyhole compared with the DSLR that I also used (22.2mm x 14.7mm). The DSLR is a pain in the neck (too big, too heavy, has a physical shutter, only runs off its own batteries) so I wanted an astro camera with a sensor about the same size as the DSLR. At that size they have relatively high read noise and are expensive for the better ones and that's why I settled on the mid-sized Uranus-C (11.2mm x 6.3mm). It's field of view is double that of my first camera but half that of the DSLR. So, I also have a x0.6 Reducer / Field Flattener which solves the problem. I've only used it once so far but it produced a great view of M31 (I posted a snapshot in this thread, page 6 about 1/3 of the way down, on October 21). Focal Reducers only really work with refractors though (I believe - mine certainly doesn't work with my Newtonian).

Since I bought the Uranus-C I've also realised that the bigger the sensor the more area the scope needs to illuminate. Some scopes struggle to illuminate a full DSLR sensor, and you get darker corners in the image (vignetting), plus the scopes inherent edge deficiencies (aberrations of various types) are worse the further out from the centre of the illumination. If you think about it, most scopes are designed for visual use where at most they have to illuminate a 7mm diameter human eye, so asking them to illuminate and remain in focus across a 27mm diagonal DSLR sensor is pushing things.

 

I ran everything through the AP tool and was pretty shocked at how much FOV I was losing with the Uranus-C. I then tossed on a reducer and saw how much I could get back, although making sure I buy the correct one has been a bit confusing. I asked around and it seems I just need to make sure it matches my scope specifications. Although many of the manufacturers are telling people that they won't work with anything besides their own scopes. 

Regardless I am solely doing AP, and targeting DSO's. I also am using a refractor (80mm) so it seems I am lined up in regards to a flattener / reducer. I have gotten SO MANY opinions across various forums on if I should or shouldn't pick up a Uranus-C. 

Obviously though you have been happy with the Uranus-C, I always felt like as a budget option it would be a nice upgrade over my old 500D, but a lot of people are kind of scoffing at the idea. So once again I got stuck... new DSLR, 1k+ AP camera... ugh

[PeterC65]

On 14/11/2022 at 13:46, Trippelforge said:

Obviously though you have been happy with the Uranus-C, I always felt like as a budget option it would be a nice upgrade over my old 500D, but a lot of people are kind of scoffing at the idea. So once again I got stuck... new DSLR, 1k+ AP camera... ugh

All I can say is that my Uranus-C is way better than my Canon EOS 1100D DSLR, both in terms of image quality and ease of use, and with the x0.6 focal reducer on my 72mm refractor the field of view is very similar.

[Adam J]

On 14/11/2022 at 06:45, MichaelBibby said:

As I understand it the lack of sensitivity is the main issue of using colour camera's, as compared to mono camera's, for guiding, but many OSC these days are very sensitive, so maybe that conventional wisdom no longer applies?

No its the Bayer matrix interfering with the sub pixel estimation of star position nothing to do with sensitivity. 

Adam

[Adam J]

55 minutes ago, PeterC65 said:

All I can say is that my Uranus-C is way better than my Canon EOS 1100D DSLR, both in terms of image quality and ease of use, and with the x0.6 focal reducer on my 72mm refractor the field of view is very similar.

How is the chromatic aberration with that x0.6 reducer? A common issue with cheap reducers below 0.8x?

Adam

[Trippelforge]

55 minutes ago, PeterC65 said:

All I can say is that my Uranus-C is way better than my Canon EOS 1100D DSLR, both in terms of image quality and ease of use, and with the x0.6 focal reducer on my 72mm refractor the field of view is very similar.

Your Canon obviously is a step up from my 500D, I think I might go ahead and give the Uranus a shot. Thank you!

[PeterC65]

Just now, Adam J said:

How is the chromatic aberration with that x0.6 reducer? A common issue with cheap reducers below 0.8x?

Adam

I've not noticed any CA. You can see for yourself earlier in this thread where I posted images of M31 and M45 using the x0.6 reducer (1/3 of the way down page 6).

My refractor is a TS Optics Photoline 72 and I couldn't find a dedicated reducer for it so bought the generic one from StellaMira (FLO). I was specifically looking to increase the field of view so wanted x0.6 rather than the more usual x0.8 or even x1.0.

[Adam J]

3 minutes ago, PeterC65 said:

I've not noticed any CA. You can see for yourself earlier in this thread where I posted images of M31 and M45 using the x0.6 reducer (1/3 of the way down page 6).

My refractor is a TS Optics Photoline 72 and I couldn't find a dedicated reducer for it so bought the generic one from StellaMira (FLO). I was specifically looking to increase the field of view so wanted x0.6 rather than the more usual x0.8 or even x1.0.

Honestly, I would say that some of the stars are slightly bloated and that you need another 1mm or so additional back focus as you have not fully eliminated the field curvature looking at M31. However, those TS 72mm (and WO 73) doublets do tend to produce slightly larger stars anyway so it may be more the scope than it is the reducer. But I guess that is why people pay for triplets. 

Adam

[PeterC65]

7 minutes ago, Adam J said:

Honestly, I would say that some of the stars are slightly bloated and that you need another 1mm or so additional back focus as you have not fully eliminated the field curvature looking at M31. However, those TS 72mm (and WO 73) doublets do tend to produce slightly larger stars anyway so it may be more the scope than it is the reducer. But I guess that is why people pay for triplets. 

Adam

That's interesting! In order to achieve focus I had to set the back focus to 53mm rather than the 55mm specified for the reducer. Doing that gives me 4mm of focus adjustment. I am planning to try 54mm of back focus to see if I can get closer to the specified 55 mm and still achieve focus.