ZWO/Player One IMX 585 Sensor Image Showcase

[Trippelforge]

19 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.

There is no way something dedicated was made for my scope. So finding one myself is going to be a task for sure. How did you match something generic up that you had a good feeling would work? 

 

[PeterC65]

1 minute ago, Trippelforge said:

There is no way something dedicated was made for my scope. So finding one myself is going to be a task for sure. How did you match something generic up that you had a good feeling would work? 

 

I asked FLO (First Light Optics) whether the StellaMira reducer would work with my scope. To be fair, they weren't sure but thought it probably would. FLO offer a 30 day return service so I just gave it a try. I've just noticed that they say it isn't suitable for the Sky-Watcher 72ED because of a lack of inward focus which is interesting as that's exactly the issue I have with my Photoline 72.

[Trippelforge]

2 hours ago, PeterC65 said:

I asked FLO (First Light Optics) whether the StellaMira reducer would work with my scope. To be fair, they weren't sure but thought it probably would. FLO offer a 30 day return service so I just gave it a try. I've just noticed that they say it isn't suitable for the Sky-Watcher 72ED because of a lack of inward focus which is interesting as that's exactly the issue I have with my Photoline 72.

 

I currently am almost out of back focus somehow and all I have on my scope is a DSLR. So does that mean that a focal reducer will actually help me out in this case?

[PeterC65]

14 minutes ago, Trippelforge said:

 

I currently am almost out of back focus somehow and all I have on my scope is a DSLR. So does that mean that a focal reducer will actually help me out in this case?

Not necessarily. In my experience adding lens based optical components just changes the focus point. It's probably possible to say in what way but I can never work it out.

[Adam J]

On 15/11/2022 at 15:51, PeterC65 said:

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.

That fits with what i am seeing. If your using any filters on the camera side of the corrector it will be even worse as you need to add backfocus to accommodate them. The only other solution is to change out the focuser for a lower profile one or shorten the tube. 

[Trippelforge]

13 hours ago, Adam J said:

That fits with what i am seeing. If your using any filters on the camera side of the corrector it will be even worse as you need to add backfocus to accommodate them. The only other solution is to change out the focuser for a lower profile one or shorten the tube. 

Back focus is extending the focuser "tube" correct? Sounds like I dumb question but I am almost out of it. I have nothing connected though but a DSLR. I keep noticing so many people talking about needing spacers so I just wanted to make sure. That raises the question, if I only use a dedicated camera will that make it better or worse?

[Adam J]

9 minutes ago, Trippelforge said:

Back focus is extending the focuser "tube" correct? Sounds like I dumb question but I am almost out of it. I have nothing connected though but a DSLR. I keep noticing so many people talking about needing spacers so I just wanted to make sure. That raises the question, if I only use a dedicated camera will that make it better or worse?

Increasing the back focus means that you need more distance (so spacers) between the rear surface of the corrector (camera side surface) and the camera sensor. This will however result in the focus tube itself (located scope side of the corrector) moving inwards and so reducing the outward focus travel.  So more spacers on the camera side as required may mean you cant reach focus if there is not sufficient inwards focus travel available in the focuser, which is the case above. 

Adam

[Trippelforge]

1 hour ago, Adam J said:

Increasing the back focus means that you need more distance (so spacers) between the rear surface of the corrector (camera side surface) and the camera sensor. This will however result in the focus tube itself (located scope side of the corrector) moving inwards and so reducing the outward focus travel.  So more spacers on the camera side as required may mean you cant reach focus if there is not sufficient inwards focus travel available in the focuser, which is the case above. 

Adam

So if I am extending my tube and hitting the limit while focusing, I would need to put in spacers to "extend" the tube farther. This explains without any spacers why I only have about an inch of extension left. 

[PeterC65]

15 hours ago, Adam J said:

That fits with what i am seeing. If your using any filters on the camera side of the corrector it will be even worse as you need to add backfocus to accommodate them. The only other solution is to change out the focuser for a lower profile one or shorten the tube. 

I am using filters, all Astronomik which are 1mm thick. Does that mean I need to add another 1mm of back focus, so 56mm between the reducer and the camera sensor rather than the specified (without a filter) 55mm?

I've tested the reducer with 54mm of back focus this afternoon and I can still achieve focus but with only 1mm of margin. I can unscrew the 2" clamp from the Photoline 72 and the clamp assembly measures 38mm so I'm looking for a way to replace the clamp with a shorter one. Maybe the Baader Ultrashort clamp plus an M63 / M68 adapter.

[Adam J]

5 minutes ago, PeterC65 said:

I am using filters, all Astronomik which are 1mm thick. Does that mean I need to add another 1mm of back focus, so 56mm between the reducer and the camera sensor rather than the specified (without a filter) 55mm?

I've tested the reducer with 54mm of back focus this afternoon and I can still achieve focus but with only 1mm of margin. I can unscrew the 2" clamp from the Photoline 72 and the clamp assembly measures 38mm so I'm looking for a way to replace the clamp with a shorter one. Maybe the Baader Ultrashort clamp plus an M63 / M68 adapter.

No so with 1mm thick filters you would need:

Standard corrector backspacing = 55mm (but can change based on focal length and design). 

Glass path correction = Glass thickness / 3 

So in your case it would be Corrector backspacing + Glass path correction = 55.33mm

But you may also have to include the camera window. So it could end up being something like 55.5mm all in all as spacers normally come in 0.5mm anyway. 

But to see so much distortion on such a small sensor you are quite a few mm out currently. 

Adam

Edited November 17, 2022 by Adam J

[vernmid]

Hi all,

Been having some fun with the ASI585MC, Evoguide 50ED and AZ GTI portable setup. 

Guiding with PHD2 Zwo mini guide scope and ASI120MM-S.

 

Managed to collect this data last night

M33 90 x 120s subs

NGC7000 30 x 120s subs

+ 10 x darks, 20 x bias and 20 x flats and a quick and dirty process in Siril. I will reprocess later but I was eager to have a quick look 🙂

Quite pleased with these for a first night out with all this kit! Also first time using Siril!

AZ GTI managed to achieve 1.5  arcsecond RMS which I was amazed ay 🙂

Just shows that the ASI585MC is actually quite capable for DSOs

Cheers

Vern

 

 

 

 

Edited November 19, 2022 by vernmid
Added photo of rig

[TerryD]

I just ordered this camera and I'm a newb.  I'm curious to learn what kind of light pollution some of you are getting these images through.  My backyard is B6.

[vernmid]

7 minutes ago, TerryD said:

I just ordered this camera and I'm a newb.  I'm curious to learn what kind of light pollution some of you are getting these images through.  My backyard is B6.

Hi Terry,

The above were from a Bottle 4. So pretty low light pollution. M33 was very high in the sky so out of the glowing lights of Southampton docks about 10 miles to the South!

Cheers

Vern

[MichaelBibby]

Up close and personal with the Sculpture Galaxy. Live stack of 54 lights (12 darks), at 65", gain 200, through a 150/750, guided shot in Bortal 3 sky. No post processing (except crop).

I used the Smart Histogram in SharpCap to determine exposure times, gain, offset, etc., but I think I'll try 90" or 120" at this gain next time. I really need to learn how to use the Smart Histogram function better...

 

And here with a bit of editing in Siril.

Edited November 24, 2022 by MichaelBibby

[MichaelBibby]

Helix Nebula. Livestack of 102 lights (no darks), at 65", gain 200, guided, 150/750. I didn't apply darks (hence the image isn't as clean as it otherwise would be) because the darks I captured last night introduce a weird colour cast into the image (also effected above image) and a checkboard (debayer pattern?), no idea why, maybe some light got in? New to all this, still so much to learn...

Edit: here is a version I made with my darks (and before I took out the satellite trail). It has less sensor pattern noise, but you can see the matrix patterning that my darks introduced.

 

 

Edited November 24, 2022 by MichaelBibby

[Trippelforge]

On 23/11/2022 at 18:26, MichaelBibby said:

Edit: here is a version I made with my darks (and before I took out the satellite trail). It has less sensor pattern noise, but you can see the matrix patterning that my darks introduced.

Wow that is pretty noticeable... why is it doing that? I hadn't seen any other examples with it being so bad. 

[vlaiv]

On 24/11/2022 at 01:26, MichaelBibby said:

Helix Nebula. Livestack of 102 lights (no darks), at 65", gain 200, guided, 150/750. I didn't apply darks (hence the image isn't as clean as it otherwise would be) because the darks I captured last night introduce a weird colour cast into the image (also effected above image) and a checkboard (debayer pattern?), no idea why, maybe some light got in? New to all this, still so much to learn...

Checkerboard pattern that you are seeing is not related to darks (at least not directly).

If you look at the image at 100% zoom level - it's gone:

It is there only when image is resized (to fit the screen for example) - if one is using some low quality interpolation resizing. With high quality interpolation resizing - it won't happen.

Here is example of the effect:

left is image viewed at 66% of original size, and right is image resampled to 66% of original size by using Lanczos interpolation.

I have noticed this effect before and I'm not 100% sure what is causing it - but my suspicion is that it is caused by linear debayering in combination with very slight rotation when aligning frames - just few degrees.

Look what happens to gaussian type noise when I rotate it by ~1 degree using bilinear interpolation (I adjusted contrast so it can be seen more easily):

Grid pattern emerges.

[Trippelforge]

9 minutes ago, vlaiv said:

I have noticed this effect before and I'm not 100% sure what is causing it - but my suspicion is that it is caused by linear debayering in combination with very slight rotation when aligning frames - just few degrees.

 

 

So is that being cause during the stacking process or raw camera output? I just wanted to check as I have been really close to pulling the trigger on the Uranus. 

[vlaiv]

3 minutes ago, Trippelforge said:

 

So is that being cause during the stacking process or raw camera output? I just wanted to check as I have been really close to pulling the trigger on the Uranus. 

Stacking process.

I believe that if data were to be stacked using Siril with say Lanczos interpolation for sub alignment - pattern would go away, but I'd be happier if someone actually confirmed that by doing it.

[Trippelforge]

2 minutes ago, vlaiv said:

Stacking process.

I believe that if data were to be stacked using Siril with say Lanczos interpolation for sub alignment - pattern would go away, but I'd be happier if someone actually confirmed that by doing it.

Thank you!

[MichaelBibby]

Yes, it doesn't seem to be the camera causing it, it's the first time I've seen it. I only stack in Sharpcap at the moment, which I imagine is pretty rudimentary. Thanks for your knowledge @vlaiv.

[PeterC65]

I had my best session yet last night with the 72mm APO and Uranus-C (now replaced by Player One and working perfectly).

First up was M33, my usual starting point ...

then some more galaxies, NGC1023 ...

and M81 and M82, two of my favourites ...

M35 and its near neighbour NGC2158 looked great ...

and then the magnificent M42, first time for me since last Winter, and the first time with a camera. Wow, just WOW!

These were all live stacked on the night, no post processing other than a bit of cropping.

 

[PeterC65]

I hope others will post their IMX585 images here. Here are some from last night using the Explorer 150PDS instead of the Photoline 72 (72 mm APO) that is my usual choice for EEVA.

My conclusion is that for faint objects (everything other than the Moon, planets and maybe M42) I need to be using a fast scope, so not the Mak, and no Barlow with either the Photoline 72 or the Explorer 150PDS. Then if I want to observe small faint objects (small galaxies is my current thing) then I need to be using the longest possible FL scope that is still fast, so the Explorer 150PDS.

Interestingly this line of thought is the same as saying that aperture remains king, even for EEVA! Now where did I put my notes about which big Dob to buy ...

For now, with the Explorer 150PDS ...

M77, showing much more detail than with the refractor.

The close by NGC1055, again more detail but I can't now see M77 and NGC1055 together.

M74 which is just starting to reveal it's lovely spiral arms.

My current favourite 'big' galaxy, M33, showing more detail I think with the larger aperture.

The Horsehead Nebula is easier to pick out with the Explorer 150PDS but I can't also see the Flame Nebula in the same field of view, so here it is separately. I know it's the scope putting the points on the stars, but they do look nice.

All of these images were live stacked on the night, with no post processing other than a bit of cropping.

 

Edited December 9, 2022 by PeterC65

[MichaelBibby]

11 hours ago, PeterC65 said:

I hope others will post their IMX585 images here. Here are some from last night using the Explorer 150PDS instead of the Photoline 72 (72 mm APO) that is my usual choice for EEVA.

My conclusion is that for faint objects (everything other than the Moon, planets and maybe M42) I need to be using a fast scope, so not the Mak, and no Barlow with either the Photoline 72 or the Explorer 150PDS. Then if I want to observe small faint objects (small galaxies is my current thing) then I need to be using the longest possible FL scope that is still fast, so the Explorer 150PDS.

Interestingly this line of thought is the same as saying that aperture remains king, even for EEVA! Now where did I put my notes about which big Dob to buy ...

For now, with the Explorer 150PDS ...

M77, showing much more detail than with the refractor.

The close by NGC1055, again more detail but I can't now see M77 and NGC1055 together.

M74 which is just starting to reveal it's lovely spiral arms.

My current favourite 'big' galaxy, M33, showing more detail I think with the larger aperture.

The Horsehead Nebula is easier to pick out with the Explorer 150PDS but I can't also see the Flame Nebula in the same field of view, so here it is separately. I know it's the scope putting the points on the stars, but they do look nice.

All of these images were live stacked on the night, with no post processing other than a bit of cropping.

 

Nice, the glories of heaven have been veiled by clouds at my location for weeks. Love F5 Newts, would never use higher focal ratio, also love the idea of F4 Newts with coma corrector reducers which bring it closer to F3. I've noticed the RASA's are very popular, along with Hyperstars, I think both are at about F2.2. Fashion seems to favour faster scopes right now, which also reducers the need for guiding and long exposures.

Edited December 10, 2022 by MichaelBibby

[PeterC65]

4 hours ago, MichaelBibby said:

Nice, the glories of heaven have been veiled by clouds at my location for weeks. Love F5 Newts, would never use higher focal ratio, also love the idea of F4 Newts with coma corrector reducers which bring it closer to F3. I've noticed the RASA's are very popular, along with Hyperstars, I think both are at about F2.2. Fashion seems to favour faster scopes right now, which also reducers the need for guiding and long exposures.

I'm sticking to F5 / F6 for DSOs, but the Moon and planets benefit from a higher F number. The accepted wisdom (for the Moon and planets only) is that the F number should be 4 x sensor pixel size, so 11.6 in the case of the IMX585. A higher F number is viable for these targets as they are very bright and so don't need a fast scop, and because they benefit from higher resolution.

I added a x2.25 Barlow to the Explorer 150PDS last night to give me F11.25 and that seemed to work well (for the Moon and planets, I didn't observe anything else). The planets were still a blur when viewed live, but hopefully that will improve after post processing this afternoon. The Moon was quite a revelation though. I used an IR pass filter with the cameras colour balance set for auto correction and the view last night was as good as with an eyepiece when looking at Moon detail. The IR pass filter removed atmospheric wobble as advertised (it doesn't seem to work for the planets though).