First mono camera: ASI294 vs ASI183 + filters suggestions - Forums

Hello,

I've been shooting DSLR for deep-sky objects for about 3 months and I'm starting to see that the costly upgrades also have limits, on top of making the editing quite complicated. So, I'm looking to get my first mono camera and was wondering if someone had recommendations.

My purpose is to get a solid starting gear that will allow me to evolve and be satisfied with it for quite some time. I'm still exploring the skies and possibilities, but I believe wide fields are more my interest (and budget haha) over "tiny" deep-sky objects. Interested in nebulae and supernovas only, not planetary, nor star clusters. Also, I'm trying to keep my current scope for a while, since these things are pretty expensive.

Here's my current setup:

Main scope: Explore Scientific AR 102 (102mm aperture, f/6.5, 663 focal length)
Main camera: Nikon D850
Autoguiding scope: William Optics 50mm f/4
Autoguiding camera: ZWO ASI290-mm mini
Current mount: HEQ-5

Regarding cameras:
With a bit of online study, I believe the two best choices for my budget would be the ZWO ASI183MM or ZWO ASI294MM (both pro and cooled versions). I'm a bit conflicted, since the ASI294 looks like it has better specs/more recent, but it has has less MP than the ASI183. Being used to my Nikon D850 with 45MP, the lower resolution bothers me.

ASI183

Resolution: 20.18MP (5496x3672)
Pixel size: 2.4µm
Sensor size: 1" 13.2x8.8mm
Sensor diagonal: 15.9mm
QE: 84%
ADC: 12 bit
Cooling: 45 below ambient

ASI294:

Resolution: 11.7M/47MP (4144x2822/8288x5644)
Pixel size: 4.6/2.3µm
Sensor size: 4/3" 19.1X13.0mm
Sensor diagonal: 23.2mm
QE: 90%
ADC: 14/12 bit
Cooling: 35 below ambient

Regarding filters:
I fell in love with the Hubble palette processing, so I was going for HSO filters. I saw the ZWO 7nm HSO kits with different sizes (1.25", 31mm, 36mm). Since the difference of price isn't so huge, I'd assume I'd be better off buying the 36mm for potential future scope upgrades?

Also, would it be worth going for individual filters and go for a more expensive / lower nanometer H-alpha, for more details?

Let me know what you think!

Thank you

Have the 183MM in combination with Astronomik 6nm HSO filters and astronomik LRGB deepsky. Your FL is almost at the end of the spectrum for the 183 and the 294 is for me the logical next upgrade. The 294 will give you a slightly wider FOV compared to the 183.

For futureproofing indeed larger filters would be better if you ever consider even larger sensor sizes.

CS

FYI - the ASI294MM has 2 modes, the published spec (4.63um pixels, 14bit ADC) now called "bin2" and the driver-unlocked "bin1" mode in the latest drivers (2.3um pixels, 12 bit ADC) - which turns it into basically a bigger ASI183MM:

Unlocked Bin1: 12bit ADC, 2.3um pixel size, 47 megapixels, 8288*5644 resolution, 14k full well capacity.
Bin2: 14bit ADC, 4.6um pixel size, 11.7 megapixels, 4144*2822 resolution, 66k full well capacity.
(source: https://astronomy-imaging-camera.com/product/asi294mm-pro)

I'd go for the 294 and I would probably run it "bin2" even, 1.5"/px is OK for my seeing. Don't focus on "empty" megapixels, see what your sky can actually deliver in terms of details with your seeing. https://astronomy.tools/calculators/ccd_suitability

If you want large pixels (for the FL) and *more* pixels, you should look for a physically bigger chip like the 2600

I have the 183MM, great camera. But far better suited for small focal lengths because of it's tiny tiny pixels.
I use mine for 250-400mm scopes. And it suits your 660mm a bit less. That's why I went for the 183MM for mine. (but sometimes wish I didn't)

The pixel size of the 294MM is better suited for your scope.
You also get a larger field of view, which helps a lot too! (the 183mm can be a bit limiting in it's field of view)

With astrophotography, megapixels don't do much.. pixel size is far more important.
you want them to be small enough to get the details, but large enough to gather as much light as possible.. all while dealing with the seeing conditions of where you are. No point in throwing millions of pixels on a bit of detail if you can't gather light fast enough, or if the seeing conditions won't allow for more detail.

the 183MM pixels are so tiny, that it sometimes takes me ages to gather enough signal to noise..I see people uploading great images after only 2-3 hours of exposures. And here I am, collecting 20+ hours on some targets.

This will be easier with the 294 because of the pixel size and the read noise. This helps deal with the aperture F6.5 of your scope.

You could always find ways to up the resolution of the 294. Dithering+drizzle for example.
And some other benefits of course, the 14bit helps too for that little bit of extra dynamic range.

so… the 294MM is probably better for you.

As for filters.
It depends.. it is kinda a "you get what you pay for" thing with filters.. I'm not familiar with the ZWO ones. So I don't know how they stack up against other brands like optolong or Baader or others.. Maybe look at reviews and such to see how the ZWO narrowband filters hold up.

either way, 7nm filters are a good way to start with narrowband imaging. And yes, you could buy filters that are large enough to future proof yourself for any upgrades you might want to do. So it is probably not a bad idea to go for 36mm to cover you for an APS-C size camera. You will in the end also want to upgrade your filters though (that's the nature of astrophotography) to a 3nm set.. But still.. it is then already better to have the 36mm filterwheel instead of having to upgrade things again.

Thank you all, that's very helpful. I'll stick with the 294 + 36mm filters.

Gear + connection wise
I'm trying to figure out if I'll have everything in hand to get started:

- The 294 comes with a "M42-M48 adapter", is this a 2" adapter for in-between telescope and camera?
- Field flatteners: from my understanding, they are made specifically for a particular scope. Which means, they are none available for my cheap telescope, correct?
- Are "extender" synonyms for spacers? Used to create sufficient distance for the backfocus?
- Considering that: 1) I can currently achieve correct focus with my DSLR and still have plenty of "zoom space" available on the telescope (pardon my lack of vocabulary!) 2) My gear is /I am too cheap to have a flattener right now 3) I only intend to add a filter wheel in between scope and camera // does this mean I won't need an extender?

What I'm assuming the simple setup would look like:

Refractor telescope
M48 to M42 adapter (maybe?)
Filter wheel
AS294 camera

Software wise
I am currently using a remote shutter/timer for the DSLR camera, not capturing pictures through software control yet. I'm also using PHD2 for autoguiding, which is working fine and hopefully I can keep using it, while starting to work with an image capture software.

To control the 294, I'm assuming I'll need something like Astro Photography Tool (APT)? Do you have any suggestions for other software, or would you recommend this one?

More confusion to come

Thanks again!

Thank you all, that's very helpful. I'll stick with the 294 + 36mm filters.

Gear + connection wise
I'm trying to figure out if I'll have everything in hand to get started:

- The 294 comes with a "M42-M48 adapter", is this a 2" adapter for in-between telescope and camera?
- Field flatteners: from my understanding, they are made specifically for a particular scope. Which means, they are none available for my cheap telescope, correct?
- Are "extender" synonyms for spacers? Used to create sufficient distance for the backfocus?
- Considering that: 1) I can currently achieve correct focus with my DSLR and still have plenty of "zoom space" available on the telescope (pardon my lack of vocabulary!) 2) My gear is /I am too cheap to have a flattener right now 3) I only intend to add a filter wheel in between scope and camera // does this mean I won't need an extender?

What I'm assuming the simple setup would look like:
Refractor telescope
M48 to M42 adapter (maybe?)
Filter wheel
AS294 camera

Software wise
I am currently using a remote shutter/timer for the DSLR camera, not capturing pictures through software control yet. I'm also using PHD2 for autoguiding, which is working fine and hopefully I can keep using it, while starting to work with an image capture software.

To control the 294, I'm assuming I'll need something like Astro Photography Tool (APT)? Do you have any suggestions for other software, or would you recommend this one?

More confusion to come

Thanks again!

Depending on the connection of your telescope all adapters that come with the camera should be enough to connect everything. So if it’s an M48 connection on the scope your sorted.

For capture software I can highly recommend NINA. It can control all your gear and has a very good sequence planner. I don’t see that you have an auto focuser but if you plan on adding it NINA AF routine will help with that also.

CS Sean

I suggest to take a look at the ASIair for taking pictures. It's very easy to use and capable of all the things you need. A great tool for beginners and lazy people like me.

I did find this flattener: Explore Scientific ES MPCC Field Flattner
It's listed as one of the accessories/"frequently bought with;" for the 102 that you have. So.. I reckon it's good for it????

Or this one: Field flattener

Both are seem to have very little specs listed on the websites.
But would appear to be for the 102.. perhaps contact resellers or Explore Scientific to ask for the best advice.

Either way, both give you the threads (M42/M48) and stuff to mount the camera onto it.
And your camera and filterwheel should come with all the bits you need to do this.

Most flatteners will require 55mm back focus (or 56 with filters)
So you'll be looking to make something like this.

As for the software.

Yes you will need a way to run the camera. Both for the imaging and the cooling.
Loads of free and good options out there like Nina and APT.

Personally I'm a fan of the ASIAIR from ZWO.
Just a all in one solution for me, and takes out a lot of the hassle of drivers and other this, especially because it's very much plug and play when using ZWO gear. It also allows planning, polar alignment, guiding, video, etc, etc.. But.. this is a personal preference. And does come with a 300 dollar price tag.

The 294 is the better camera. As was mentioned, there are 2 modes: the default 11MP mode and the unlocked, 47MP one. The unlocked mode makes the 294 look a lot like a bigger sensor 183.

I think the 11MP mode is plenty. It is a native resolution of 4144*2822. Collect enough data and you can do a 2x drizzle integration to get you an image of 8288*5644. Here's an example of just such an image I did:

The Soul Nebula in SHO

There are a couple of things to note with your scope. The first is that it's an achromat. That's fine for visual, but can cause some bloating issues in imaging. Usually it can be seen in the blue channel. It _might_ not be as noticeable with a mono cam and filters since you are independently shooting each channel. For a flattener, you can use the Hotech 2" SCA.

Filters... you will notice definitive halos around brighter stars with the cheaper brand filters. If you're planning on upgrading your camera to an APS-C at some point, then it might be a wise choice to get the 36mm filters now. Otherwise, you don't need more than 31mm.

Thank you again everyone, that's really useful info.

For the field flattener, I'll go for the Hotech 2" SCA that Jonny suggested, since the Explore Scientific one didn't seem too appreciated and specific to their apochromatic / ED telescopes.

For distance control: I'll most likely take a look in the future for the ASIAIR, once I'll feel better after swallowing the first invoices

I'm currently using a laptop outdoors plugged to the mount/camera and I control the laptop through my desktop computer. I tried using the Quick Assist from Windows (TERRIBLE popups to accept on both sides) and ended up using Chrome Remote Desktop, which is way better since I can just pop in to check if it's still guiding (no popups!).

If you had to control your laptop by distance, would you recommend something else?

I'd really like to control via home network instead of going through Internet/streaming, but not too sure if they are easy solutions for that. Something that wouldn't involve having to get out and accept taking control over and so on.

Thank you again everyone, that's really useful info.

For the field flattener, I'll go for the Hotech 2" SCA that Jonny suggested, since the Explore Scientific one didn't seem too appreciated and specific to their apochromatic / ED telescopes.

For distance control: I'll most likely take a look in the future for the ASIAIR, once I'll feel better after swallowing the first invoices I'm currently using a laptop outdoors plugged to the mount/camera and I control the laptop through my desktop computer. I tried using the Quick Assist from Windows (TERRIBLE popups to accept on both sides) and ended up using Chrome Remote Desktop, which is way better since I can just pop in to check if it's still guiding (no popups!).

If you had to control your laptop by distance, would you recommend something else?

I'd really like to control via home network instead of going through Internet/streaming, but not too sure if they are easy solutions for that. Something that wouldn't involve having to get out and accept taking control over and so on.

Not sure what version of Windows (assuming Windows) you're running on your laptop. If it's Windows 10 Pro, it has Remote Desktop built in. That's how I control my scope-side computer from inside the house. I've got a miniPC on the mount (a Beelink) with Windows 10 Pro on it. It runs NINA, PHD2, iOptron Commander, ASTAP, etc. I set my rig up at the end of my driveway, push one button to power things on, then polar align. At that point, I can go back into the house - or if it's a nice enough night, spend some time under the stars.

Thanks!

What would be the advantages/disadvantages of each? Like latency and performance wise, if there's a noticeable difference or if it's a personal preference.

Laptop + remote control to indoor desktop;
Mini PC + remote control to indoor desktop;
ASIAIR to indoor desktop;
Other scenario...?

294 ordered and waiting to get my hands on it!

Since I'm into deep sky imaging, I don't much care about the performance of my scope-side computer. As long as it can run NINA, ASTAP and PHD2, that's pretty much everything I need from it. I don't like leaving my laptop out at the scope. Not only does it use a lot more power, but it's got the keyboard, touchpad and screen that I'd rather not leave in the elements. Plus, it costs considerably more than the Beelink I use. I think I got the Beelink for $200 on Amazon. My laptop was considerably more expensive.

Thanks!

What would be the advantages/disadvantages of each? Like latency and performance wise, if there's a noticeable difference or if it's a personal preference.
Laptop + remote control to indoor desktop;
Mini PC + remote control to indoor desktop;
ASIAIR to indoor desktop;
Other scenario...?

294 ordered and waiting to get my hands on it!

I can only comment on the ASIAIR, as it's the only thing I've ever really used.

Because trying to set up drivers, Nina, phd2, sharpstar and all the other stuff.
On MacOS running a bootcamp windows... yea.. no.. that wasn't a succes.

ASIAIR has so far been very nice. Pretty much plug and play. I've had the Original ASIAIR, the ASIAIR Pro and now the ASIAIR Plus, and clearly more and more improvements are being made. Both in hardware and software.
The original one works, but is a bit slow (and limited features).
The Pro works great, a lot of features, but bad wifi (which can be fixed)

The PLUS fixes the main issue of the previous generation, which was the wifi connection. it's so much better and faster now. And far better range. So I'm very pleased. latency and performance have not been any issue. And I can comfortably look at my imaging session from inside on my iPad. Controlling is pretty much instant. And images take only a second or 2 to load.

ASIAIR is a bit of a personal preference. The main issue you will face would be that you're limiting yourself to ZWO products.
Personally I'm very happy with ZWO products, and it's not a bad product-line to be "stuck" in.. But, it's not for everyone.

And the ASIAIR does lack some..... let's call it.. "finer control" that you might be able to get with NINA or other software.
But, I will say that they have been improving this A LOT in the last months. With multi-star guiding, proper planning modes for multiple targets, more control on focussing, etc.

As for a mini PC/laptop.

Again, not a user of it, but have researched enough. (And might get one for a remote rig at my brothers place in a different country)
Basically you need enough to run the programs and storage for the images..that's about it. Imaging isn't that intensive on a computer if you only use it for imaging. (Obviously it's a different story if you also want to do stacking/processing on it)
most come with windows 10, which has Remote Desktop built in. So connecting to it from inside would be very easy.

Latency and performance is then pretty much relying on your wifi/connection.

There is a forum thread here: About mini PC's

And I would probably prefer a mini PC over a laptop, just because they can deal with the elements a bit better. Rather than delicate screens and touch screens. + cheaper to replace if one does break down.. Obviously though, if you're on a budget and you have a spare laptop laying around, that can still be an option.

@Steven De Vet: that's super helpful again, thank you. Out of curiosity, if one was not completely satisfied with the ASIAIR software they provide: Could they use NINA in combination with the ASIAIR device? Or can the ASIAIR device only be used with their own ASIAIR software?

Financially wise, the ASIAIR isn't that expensive versus a mini PC. So that's probably in my future upgrades.

Well... here we go, just received the 294 and got questions for basic setup already! I'm not gonna be using an off axis guider.

Telescope
M42 adapter for telescope (I took it out of an off axis guider box)
M48 female to M42 male Extender 16.5mm
[insert black hole here]
M42-M42 adapter (male to male)
Filter wheel
Camera (connect directly to FW looks like?)

Their diagram shows a T2 extender 11mm, that I didn't get in the boxes (and not shown on the list of what's included online). They also gave me a M42 female to M42 male (21mm). So it leaves me with a male end no matter what, whichever extender I choose and whether I combine both or not.

I'm assuming the missing link is a M42-M42 female to female, maybe being that M42-M42 extender (or T2) 11mm shown on diagrams?

Is this a usual piece to have to buy it on the side, or am I wrong on how to connect?

Thanks again!

You did get the 11mm… it's that black ring on your camera (labeled 7 in your image). Unscrew that. Then, you screw the camera directly into the filter wheel. Your image train should look like this:

Scope -> Hotech -> M42-m48 adapter (the bottom one in your image circled in red on the right side) -> 16mm extender ring (same circle on the right side)-> 11mm extender ring (on your camera) -> T2-T2 adapter -> EFW (take off that whatever it is on the right side in your image)-> 294

Thank you so much! You're a rage saver.

I'm assuming you meant the piece no 3 on the previous picture for the 16.5mm extender, instead of the right piece in the circle. This piece was something else and photo was not really representative of that (1.25" T nose piece I believe they call it?)

T2 are synonyms to M42?

Hopefully the picture below looks right to you! Really really hope so haha

Ahh... I didn't see that 16.5mm adapter already on the Hotech in your first image.

This looks exactly right.

This looks exactly right.

Then I shall sleep well tonight!

Next step will be researching about backfocus and I believe I'm good to go for software learning after. One should hope anyways.

Thanks again and have a great night

Your research on back focus should be pretty short, since you've got it set properly according to the Hotech specs.

Back focus can mean a few things, but typically when it is being discussed for astrophotography, people want to know "how far behind my flattener/reducer do I need to put my camera's sensor?"

Unfortunately, the answer is "it depends". A number of manufacturers use 55mm. This is why cameras from ZWO come with the spacers to get you 55mm. It's a standard from the days of DSLRs and T-mounted lenses. However, not all manufacturers follow this principle. For example, the William Optics 6AIII I have on my GT81 specifies a distance of 62.1mm. The same 6AIII strapped onto the back of a GT71 requires 64.1mm. Frustrating, right? Oh, and if you've got a filter in the light path, well you need to add 1/3 the thickness of the filter to your back focus requirements. In other words, if your particular setup says the sensor needs to be 55mm behind the flattener, and you put a 3mm thick filter in there, then you actually need to be 56mm back. Why? Because the filter causes the light to refract just a little bit and changes the distance. You can even do the math to prove it to yourself if you're bored and remember your trigonometry

@Steven De Vet: that's super helpful again, thank you. Out of curiosity, if one was not completely satisfied with the ASIAIR software they provide: Could they use NINA in combination with the ASIAIR device? Or can the ASIAIR device only be used with their own ASIAIR software?

Financially wise, the ASIAIR isn't that expensive versus a mini PC. So that's probably in my future upgrades.

Glad I can help. And no. The ASIAIR is the only the ASIAIR.
It's ZWO and I'm afraid that it can't be used in any other way really.

You can't upload NINA onto it. And can't use camera's/focusers that aren't ZWO. It's one of the downsides.
Maybe look on YouTube, loads of videos around that show how asiair works and is set up. To see if it's something for you.

Either way, congrats on the setup. Looks great, and glad you got the hang of the back focus.

So TECHNICALLY, the field flattener specs is what determines the back focus required, unless... something from the telescopes specs changes that?

For example, the William Optics 6AIII I have on my GT81 specifies a distance of 62.1mm. The same 6AIII strapped onto the back of a GT71 requires 64.1mm.

By curiosity, what's the reason of that difference between your GT71 and GT81 scopes that creates that gap? How did you come to these specific measurements?

For the thickness of each element of my setup I could find online:

M42 adapter for telescope --> doesn't count since it's threaded inside next piece
16.5mm extender
11mm extender
T2-T2 adapter --> 2mm (!)
EFW --> 20mm
ASI 294 --> 6.5mm

= total of 56mm

(!) The T2-T2 adapter length was from info I found online and what I could see with a ruler. Maybe a tad less than 2mm, but it didn't look like as small as 1mm.

With what you said regarding filter affecting the back focus length required: the thickness of the filters are 2mm. So, about +0.67mm

So... wouldn't that bring me to closer to 57mm instead of 55? Would this affect much?

So TECHNICALLY, the field flattener specs is what determines the back focus required, unless... something from the telescopes specs changes that?
For example, the William Optics 6AIII I have on my GT81 specifies a distance of 62.1mm. The same 6AIII strapped onto the back of a GT71 requires 64.1mm.

By curiosity, what's the reason of that difference between your GT71 and GT81 scopes that creates that gap? How did you come to these specific measurements?

For the thickness of each element of my setup I could find online:
M42 adapter for telescope --> doesn't count since it's threaded inside next piece
16.5mm extender
11mm extender
T2-T2 adapter --> 2mm (!)
EFW --> 20mm
ASI 294 --> 6.5mm

= total of 56mm

(!) The T2-T2 adapter length was from info I found online and what I could see with a ruler. Maybe a tad less than 2mm, but it didn't look like as small as 1mm.

With what you said regarding filter affecting the back focus length required: the thickness of the filters are 2mm. So, about +0.67mm

So... wouldn't that bring me to closer to 57mm instead of 55? Would this affect much?

To answer the first part of your post, the determination is made by William Optics. They are using the same glass on two different aperture scopes. If you go to the WO page for the 6AIII, you'll see the chart showing the required back focus distance for the scopes (there are 4 I think that use the 6AIII).

You're adding that 0.67 to the wrong side of the equation. The spacers/adapters/EFW/etc you have add up to 56mm. The back focus requirement of the Hotech flattener is 55mm. It is to THAT side you need to put the 0.67mm. So:

Hotech + 2mm thick filter = 55.67mm distance required
16.5mm extender + 11mm extender + 2mm T2 adapter + 20mm EFW + 6.5mm camera = 56mm of distance you can achieve

You're likely not going to notice that 0.33mm difference. If you do? Well, they sell shims and spacers

You're likely not going to notice that 0.33mm difference. If you do? Well, they sell shims and spacers

Give me a couple years and I'll get back to you on that

I gave a try to APT and then NINA, but I'm so glad you suggested NINA. I'm mostly just exploring the software, but was very impressed that everything worked fine on the first try for mount connection + camera connection + autoguide AND on top of that, logical layout/easy to understand and navigate. Was expecting a fight and the door slammed right open... already can take some pictures!

O so happy and grateful of everyone's help

Thank you all!