Pick me a camera?

[jetstream]

I have a 90mm SV f7  triplet apo and want to image DSO like nebula. Mount is AZEQ6. What camera would be good for this scope?

[vlaiv]

Budget, mono + filters vs OSC preference?

[jetstream]

2 minutes ago, vlaiv said:

Budget, mono + filters vs OSC preference?

I want the potential for good success and with a buy once cry once strategy.I'm thinking mono with filters and the budget can accomodate a goodly amount. I forgot this Vlaiv- do I need flattener? This might be wrong one eventhough listed for my scope.

"Focal Reducer/Field Flattener for SVR90T Apochromat

This reducer/flattener is optimized for our SVR90T triplet lens. The flattener threads into the Feather Touch or Stellarvue 2.5” focuser. The 0.8X focal reduction converts the 90mm f-6 to f-5.6 and reduces the focal length to 504 mm.

This reducer flattener has a standard 42 mm filter thread. Standard 2" filters can be added to the reducer/flattener when imaging. The backfocus of the unit is 55 mm. Since a DSLR with t-ring has a 55 mm backfocus, thread it into the cameras t-ring and then screw it to the focuser as shown below."

[vlaiv]

29 minutes ago, jetstream said:

I forgot this Vlaiv- do I need flattener? This might be wrong one eventhough listed for my scope.

If you use larger chip then yes, you want flattener - with or without reduction. These scopes have curved focal plane and sensor is of course flat - which means that odds are, corners are going to be out of focus and show bloated and astigmatic stars on larger sensors (smaller sensors will be enough in focus for this not to happen).

Only problem that I see with said reducer flattener is back focus. Sensor needs to be mounted 55mm from back thread of flattener. This does not leave much room for all accessories like filter wheel, rotator, OAG if you plan to use any of them (well, you do plan to use filter wheel but that will use up only 20-30mm of optical path - so you are good there unless you need OAG and or rotator).

Btw there is no such thing as standard 42mm filter thread - there is T2 thread which is 42mm and there is 2" or M48 thread and 1.25" or M28 thread which are filter threads

This seems to be very good camera:

https://www.firstlightoptics.com/zwo-cameras/zwo-asi-2600mm-pro-usb-30-cooled-mono-camera.html

But its relatively new and there is not much feedback on it - so others might step here with relevant information.

You'll also need filters of course - probably 36mm unmounted with that sensor size, and suitable filter wheel.

[jetstream]

37 minutes ago, vlaiv said:

This seems to be very good camera:

Thanks Vlaiv I had no idea they were so expensive!

If we were to pick a cheaper one?

[vlaiv]

3 minutes ago, jetstream said:

Thanks Vlaiv I had no idea they were so expensive!

If we were to pick a cheaper one?

That is why I asked about your budget.

With 4/3 sensor - you can use 1.25" filters - so that reduces cost as well.

There are three popular choices for 4/3 sensor:

https://www.firstlightoptics.com/zwo-cameras/zwo-asi-294mm-pro-usb-30-cooled-mono-camera.html

https://www.firstlightoptics.com/zwo-cameras/zwo-asi1600mm-pro-usb-3-mono-camera.html

https://www.firstlightoptics.com/atik-cameras/atik-383l-plus.html

I personally have ASI1600mm camera and I'm happy with it, although some people report having microlensing issues with it. It seems to depend on F/ratio of the system and optical components and their spacing (filters, flatteners and such).

ASI294 is a bit better - a bit larger, better QE, no issues with microlenses - but it is a bit more expensive.

KAF8300 is old CCD technology that requires really long exposures - but is otherwise as capable in producing excellent images.

If that is still expensive, then you are only left with this option:

https://www.firstlightoptics.com/zwo-cameras/zwo-asi-183mm-pro-usb-3-cooled-mono-camera.html

but that is only 16mm diagonal.

It also has rather small pixels so you'll need to bin your data after acquisition - that is really not big issue once you get used to it. I do it all the time on my long focal length scope and ASI1600.

And those would be really all sensible options. I would personally advise you not to go with non cooled models as cooling is essential for proper calibration.

[jetstream]

4 hours ago, vlaiv said:

There are three popular choices for 4/3 sensor:

Thanks Vlaiv!

[The Lazy Astronomer]

I don't have much experience, and can't comment on the performance of Vlaiv's other suggestions, but I'm really enjoying my 294MM. I have seen others in agreement that it is a good upgrade from the 1600MM.

Plus, you have the option of 2 different 'modes': the small pixel mode which unlocks the subpixel architecture for 2.31um pixels, or the 2x2 (hardware binned) mode for 4.63um pixels. My understanding of this is that it essentially allows you to choose between 2 different pixel sizes so you can choose whichever is the better is the better match for your setup with regard to sampling rate*.

 

*I probably don't know what I'm talking about, so if Vlaiv comes back and says that's all nonsense, he's definitely right 😀

[vlaiv]

10 hours ago, The Lazy Astronomer said:

I don't have much experience, and can't comment on the performance of Vlaiv's other suggestions, but I'm really enjoying my 294MM. I have seen others in agreement that it is a good upgrade from the 1600MM.

Plus, you have the option of 2 different 'modes': the small pixel mode which unlocks the subpixel architecture for 2.31um pixels, or the 2x2 (hardware binned) mode for 4.63um pixels. My understanding of this is that it essentially allows you to choose between 2 different pixel sizes so you can choose whichever is the better is the better match for your setup with regard to sampling rate*.

 

*I probably don't know what I'm talking about, so if Vlaiv comes back and says that's all nonsense, he's definitely right 😀

You are quite right - that is one of advantages of 294MM. In fact, I would advocate to shoot at 2.31µm and then bin later in software as that gives you more options like x3 bin if 4.63µm pixels are too small and go for 6.93µm instead.

[Jonny_H]

Hi all, sorry to hijack but I am also going through this predicament at present. Cannot decide which camera to go for although have isolated down to a few potential candidates.

My current setup is a SW 150PDS, HEQ5 Pro using a 400d unmodified dslr. Slowly building out my kit with a guides scope and camera coming soon (probably 50ed with asi120mm).

I would like a one shot cooled colour camera and have been looking at the following 3:

ASI183MC PRO

ASI533MC PRO

ASI294MC PRO

All seem to, on paper at least, fit the bill with my setup although the 183 probably falls just outside of some 'recommended' parameters.

Any comments or other suggestions welcome 🙂

Thanks,

Jon

[vlaiv]

3 hours ago, Jonny_H said:

Hi all, sorry to hijack but I am also going through this predicament at present. Cannot decide which camera to go for although have isolated down to a few potential candidates.

My current setup is a SW 150PDS, HEQ5 Pro using a 400d unmodified dslr. Slowly building out my kit with a guides scope and camera coming soon (probably 50ed with asi120mm).

I would like a one shot cooled colour camera and have been looking at the following 3:

ASI183MC PRO

ASI533MC PRO

ASI294MC PRO

All seem to, on paper at least, fit the bill with my setup although the 183 probably falls just outside of some 'recommended' parameters.

Any comments or other suggestions welcome 🙂

Thanks,

Jon

Out of those three, I would personally pick 294.

It is gives most value for your money as it is the largest sensor of the three and not much more expensive than the other two.

[Jonny_H]

Thanks vlaiv.

From what I can see the 533 wins over noise reduction and zero amp glow or at least claims to. Are any of these really an 'issue' with the 294? Everything else - the 533 seems to be either on par or give the 294 a run for its money.

I have a lot of thinking to do but good speaking to people who have actually got, tried and testes these cams. All well and good looking at the stats on paper but as with everything it is the performance when out in the field is the key!

Thanks,

Jon

[vlaiv]

1 hour ago, Jonny_H said:

Thanks vlaiv.

From what I can see the 533 wins over noise reduction and zero amp glow or at least claims to. Are any of these really an 'issue' with the 294? Everything else - the 533 seems to be either on par or give the 294 a run for its money.

I have a lot of thinking to do but good speaking to people who have actually got, tried and testes these cams. All well and good looking at the stats on paper but as with everything it is the performance when out in the field is the key!

Thanks,

Jon

Some people had issues with calibration of 294 - but I think it was mostly down to doing "automated" capture rather than selecting good capture values (mostly flat calibration was the issue).

I think there are a lot of happy 294 users.

For me amp glow was never an issue with cooled cameras as it calibrates out nicely with proper dark frames.

[Jonny_H]

1 hour ago, vlaiv said:

Some people had issues with calibration of 294 - but I think it was mostly down to doing "automated" capture rather than selecting good capture values (mostly flat calibration was the issue).

I think there are a lot of happy 294 users.

For me amp glow was never an issue with cooled cameras as it calibrates out nicely with proper dark frames.

OK that's useful to know - thank you. I guess the other advantage over the 533 is that with the 533 I will most likely need a reducer for a bigger fov to capture some targets.

Appreciate that with the likes of Andromeda I would need a reducer even with the 294 with my focal length!?:

Well - looks like I will be driving myself mad for the foreseeable deciding between these two! 😜

@Jetstream - apologies again for hijacking your thread.

 

Thanks,

Jon

[rickwayne]

Well, you don't have to bin with a 183. But they are pretty small pixels. The "sweet spot" for that sensor is a fairly fast, fairly wide-field scope like my SV-70. It's certainly a worthwhile camera. The price was one reason I went with it over the 1600.

I have a Stellarvue flattener/reducer with a 55mm back focus, and am using it with an OAG and filter wheel. It just barely works, but it works. I have to get the pickoff stalk in just the right position and there's no room for a helical focuser for the OAG, so I have to focus the guide cam like porcupines make love: very, very carefully. But once it's set up, it works great.

The 183 sensors have crazy amp glow. Absurdly so. Scaling darks is not an option, I absolutely have to have a set for each exact combination of temperature, exposure time, and gain. (That's a big reason I only use two combinations!) With  that caveat, the glow calibrates out and great images can be obtained. Even I can do some acceptable ones (check my astrobin for examples).

[vlaiv]

2 hours ago, Jonny_H said:

Appreciate that with the likes of Andromeda I would need a reducer even with the 294 with my focal length!?:

There is a neat trick that you can use to make same result as if having twice as short focal length scope.

You image 4 panels to cover the target. Each panel you image for only 1/4 of the time. Say you wanted to image for 4h total - then you spend 1h on each panel.

Next you stack each panel and stitch whole image together and you bin your image in the end x2.

That will produce the same result as if you were using scope with twice shorter focal length and same F/ratio as you already have - only difference will be in overlap between panels - so you'll use about 5-10% of width and height. Other drawback is that it is a bit more involved to process than single panel image.