17 replies to this topic

[martinontheroad]

I find I am in need of a truly portable travel telescope. I have a 70mm and a 120mm refractor and an ASI294MC Pro to do the “heavy lifting” for me. I am wrestling over whether or not to order s Dwarf 3 now, or wait until the S30 Pro is announced (and delivered).

I have compared the telephoto optics and sensors of each smart scope, and THINK I’ve done a reasonable analysis. However, I am unable to see a clear “winner.”

Telephoto Optics
Dwarf 3: 150mm fl, 35mm aperture, f3.85, 4 or 5-element APO

S30 Pro: 150mm fl, 30mm aperture, f/5, 4-element APO

Slight nod to the Dwarf on aperture, but lens sharpness and correction is not accounted for

Sensors
Dwarf 3

Sensor: IMX678 Starvis 2
Frame size: 1/1.8” (8.86mm diag.)
Pixel Pitch: 2.0um
Resolution: 3840x2140, 8.3 Mpx
Well depth: 11.6 ke
Read noise: 2.43 - 0.42e
QE: 83%
ADC: 12-bit
SNR: 42dB
FOV: 2.93 x 1.65 deg or
2.75 arc-sec/px


Seestar S30 Pro
Sensor: IMX585 Starvis 2
Frame size: (12.85mm diag) 11.2x6.3 mm
Pixel pitch: 2.9um
Resolution: 3840x2140, 8.3 Mpx
Well depth: 47ke
Read noise: 0.8 e
QE: 91%
ADC: 12-bit
SNR: 88dB
FOV: 4.3 x 2.4 deg
3.99 arcsec/px

Sensor-wise, the advertised S30 Pro seems to have the upper hand: its IMX585C is a 50% larger sensor than the Dwarfs IMX678. The 585 sensor also has about 4x more full well capacity, and an additional 46db of SNR (88dB vs 42dB). Read noise, from what I could find, is about the same. The Dwarf 3’s sensor pixels are about 1/3 smaller, which (per Astronomy Tools) allears to be a better match for the focal length. The FOV of the Dwarf 3 is about 2.75 arc-sec/pixel, whilst that of the S30 Pro is 3.99 arc-sec/pixel.

In comparison, my Ha-modified T3i with my 150mm f/4 Sonnar lens has an FOV of 5.9 arc-sec/pixel. My ASI294MC, coupled with my AT70ED scope and 0.8x flattener/reducer, has an FOV of 2.78 arc-sec/pixel - an even match with the Dwarf 3.

I am attracted to the sensor capabilities of the IMX585, but am a bit concerned about the FOV per pixel. Would I come to regret that in the long term, or would I be better off with the better well depth of the 585 chip? I’d appreciate your thoughts.

Clear Skies to All!

Edited by martinontheroad, 11 June 2025 - 10:24 AM.

[Airstrike]

I waited 4-5 months after release for D3 to arrive at the door in the end got fed up with waiting ,i got money transfered and bought the S50 best decision i made , the resolve and detail is incredible on the S50 truly amazing bit of kit

 

Keep in mind S30 PRO is still being tinkered with behind closed doors , so although S30PRO is not on the shelves yet i personally would wait till its release , i feel ZWO has the upper hand to make its product leapfrog "if it already hasnt" the D3 with features and enhancements before its release which im sure they will to stay well in front of the competition

 

me personally
1 S30PRO still in the factory getting bigger and better as we speak

2 ZWO amzing products all round

3 Take my money ZWO    

Edited by Airstrike, 11 June 2025 - 02:58 AM.

[Astronotrip]

not sure you want a wider FoV... they have mosaic mode for that. 
With a wider field you will miss out on the small objects. 

 

I d go wih the Seestar S50 instead because of the bigger aperture and focal length, you ll get more light vs the 30mm and 35mm of the S30 and Dwarf3.

The S30 Pro will probably just be a sensor update so not sure it's really worth the wait...
In any case, if you go for a Seestar, here is $20 OFF (promo code jABm0lsgiM0JFao)

Edited by Astronotrip, 11 June 2025 - 01:43 PM.

[martinontheroad]

I already own 70mm and 120mm refractors paired with an ASI294MC Pro, so they can do the “heavy lifting” for me. I just can’t always take my full rig on family trips. I’d like something portable, a bit wider field for most nebular regions, with a sensor larger than 2MPx. The truly wide field camera on the Dwarf 3 is a plus for Milky Way imaging, too.

[CraigR]

You glossed over the most important detail — 3.99 arcseconds/pixel for the S30 (and the upcoming S30 Pro) is worst-in-class and is arguably worst-everywhere. Images will be less detailed than literally every other scope.

 

At 2.75 arcseconds/pixel, the Dwarf 3 is not as good as the S50, but it has a larger FOV and a reasonable price.

 

If I were forced to make a decision today based on specs alone and not taking into account software and other things not immediately obvious from the spec sheet, I'd be looking at the Vespera II. It's basically the S50 with 4x the FOV and 3x the price. But since I don't have to make that decision today, I'm giving ZWO time to pick a direction for the S50 Pro and maybe announce an S70. The S30/S30 Pro isn't even on the list, let alone crossed off it.

[BlueMoon]

 

I am wrestling over whether or not to order s Dwarf 3 now, or wait until the S30 Pro is announced (and delivered).

With my naturally cynical nature, I tend to treat "pro" models as little more than the standard version with a few things added in that should have been in the standard version to begin with. Marketing depts love "pro" models. 

 

I'd go for the Dwarf. This based on a similar comparison between it and the S30/S50 models I made recently for myself in entering into the realm of "smart telescopes". The Dwarf checked the boxes for me. Cheers.

[Astronotrip]

You glossed over the most important detail — 3.99 arcseconds/pixel for the S30 (and the upcoming S30 Pro) is worst-in-class and is arguably worst-everywhere. Images will be less detailed than literally every other scope.

 

At 2.75 arcseconds/pixel, the Dwarf 3 is not as good as the S50, but it has a larger FOV and a reasonable price.

 

If I were forced to make a decision today based on specs alone and not taking into account software and other things not immediately obvious from the spec sheet, I'd be looking at the Vespera II. It's basically the S50 with 4x the FOV and 3x the price. But since I don't have to make that decision today, I'm giving ZWO time to pick a direction for the S50 Pro and maybe announce an S70. The S30/S30 Pro isn't even on the list, let alone crossed off it.

I d agree with that - and not because I own a Vespera 2

 

I took it with me to Tenerife a couple of time, fits in a regular backpack !

 

and I ve got a promo code as well here with Vaonis (because I m subscrived to a magazine they re partnered with) if you need, let me know, 10% off everything

[bradhaak]

building on what CraigR wrote.

 

I was a very early owner of the Dwarf 3. Mine was part of the first 100 unit shipment, and I was very disappointed. As you would expect, it is very slow to get enough light for a decent image, but if you give it enough time, the D3 can make beautiful images. 

 

The biggest problem was the software. No preferences were saved from session to session, and setting up to take a shot had to be done in a specific order, or you'd lose changes you'd already made. The app crashed a few times, too.

 

The end result was that I sold it to buy an S30. And, the S30 is great within it's own limitations. It's too small, also, but with it's lower pixel count it's not so noticeable. And it's the best grab-and-go scope I've ever had. I can throw it in my pack when I lead night hikes, and somewhere during a break, I can set it up and give a quick tour of the sky. But as slow as it is at its normal resolution, capturing a large shot with its very cool mosaic mode takes forever. And this is why I have zero interest in the S30 Pro. It's going to have the same aperture and focal length with four times as many pixels. It's very likely that it will be even slower than the Dwarf 3, and it's very likely that it will cost even more.

 

BTW - I borrowed a friend's Dwarf 3 to create a set of accessories for my Etsy store, and I found that the app has been hugely improved over the last six or seven months. It's not as simple as the Seestar app, but it exposes a lot more advanced choices. I ended up buying a second one, and am very happy with it. It will fill the role of a widefield grab-and-go scope, whether it's for a trip or even for nights at the club's dark site when I just don't feel like carrying something bigger.

 

So, the S30 is pretty good, but I don't see a reason for the existence of the S30 Pro except to compete with the Dwarf 3. And from what's been released, it doesn't bring much new to the game.

 

So that's my view. Why wait for the S30 Pro when you can buy a smaller scope today that has a slightly larger aperture and faster optics?

Edited by bradhaak, 11 June 2025 - 03:51 PM.

[eyeoftexas]

 

BTW - I borrowed a friend's Dwarf 3 to create a set of accessories for my Etsy store, and I found that the app has been hugely improved over the last six or seven months. It's not as simple as the Seestar app, but it exposes a lot more advanced choices. I ended up buying a second one, and am very happy with it. It will fill the role of a widefield grab-and-go scope, whether it's for a trip or even for nights at the club's dark site when I just don't feel like carrying something bigger.

 

 

Interesting.  From reading many of your past comments it seemed that you ditched your D3 because of the time it took to take a decent shot.  But now the improvements of the app have overcame that problem?  Would you now recommend the D3?

Edited by eyeoftexas, 11 June 2025 - 09:42 PM.

[bradhaak]

Interesting.  From reading many of your past comments it seemed that you ditched your D3 because of the time it took to take a decent shot.  But now the improvements of the app have overcame that problem?  Would you now recommend the D3?

Mostly true.

 

In this thread, I'm recommending it over the S30 Pro because the S30 Pro is going to be even slower. Same size sensor, smaller aperture, and slower focal length ratio, aren't a winning combination. But most of my statements about the slow acquisition times were in comparison with the Seestar S30. If you want to see something fast, the S30 is much better. If you use the full mosaic mode with the S30, it and the Dwarf 3 take very similar times. That was my main speed criticism and is still true. Of course, I'm starting to acquire data from Rho Ophiuchi on my Vespera 2, and that's probably going to take at least thirty hours of data (maybe more) so it's all relative.

 

Also, I was very critical of the app. It was completely modal, meaning that if you took things out of sequence when setting up a shot, or if you went back to change a setting, everything you'd done later was lost. It was also somewhat crashy and did crash a number of times. But based on a number of nights using the loaner, those complaints are no longer true. Also it's internal stacking/stretching/enhancement has greatly improved.

 

And most of the new features that were promised for introduction weren't present, months after release. Mosaic mode still isn't there, but with its huge FOV, that's a detail that I don't really care about. The rest of them are there and work as intended.

 

Finally, the one I had was from the very first production run of around a hundred units. Based on recent experiences, I now know that it never did work completely right.

 

Is it still very slow acquiring data? Yes, it is. But if you go back and read my posts, I always said that with sufficient time you could get a good image with it especially if you processed from the FITS subs. But a sufficient time was often excessive. Still true, but manageable if the other issues have been resolved, which for the most part, they have.

 

IOW - the speed or lack thereof is inherent. But the rest of the issues that made me sell it are resolved, including the early quality issues. When it shipped, it wasn't even close to ready for prime time. Now it is. And if you check my Sig, you'll see that I brought it back to the flock. B&H had them in stock and ready to ship, so I took a flier on it. so far, so good.

 

But I'll stand behind everything I said about it in its early days. It was true then, and some of the underlying things are still true. But a 4K sensor in a scope that small is a lot of fun if the scope and the software actually work as intended. They didn't then, but I think that unlike last September, now they do.

[eyeoftexas]

Good to hear.  I also grabbed one of the first D3 but have been turned off by the app.  I understand the concept of giving the user many choices and such, which probably comes from its original birth (D1) as a camera, not a smart telescope, but it can be very frustrating if there are large gaps in the times you use it, trying to remember where everything is and setting up a shot.  If there is a chance of setting up a scope to capture an image, I turn first to the S50.

[Starlancer]

The dwarf has better optics then the current S30, ZWO will have to improve the S30pro's optics by a substantial amount, especially with the larger sensor.  (I would have much rather seen a S50 with the 585 sensor.  

 

As for the app, if you have setup a scope with an ASIair then the Dwarf is no more difficult, it's actually easier.  I don't find the app confusing, yes there are more options but if you run the default Astro setting you will get decent images, it works well in either Alt-az mode or EQ mode.  I will almost always use EQ mode and hardly have any subs that need to be tossed.  Alignment is very easy and just following the app instructions works perfectly for alignment.  

 

The Seestar is a bit easier but once you get past that initial phase of learning I feel like the extra options with the Dwarf are very beneficial.  

 

I would hope that the S30pro also comes with software that allows more options similar to an ASIair.

 

Is the dwarf perfect?  Nope, Wifi is OK but if you use a mesh system the dwarf and the controlling device have to be on the same node.  The atlas could be improved, it's OK and works fine, but I don't like that it tends to jump to an object even if you want to center on an empty area (It's a minor gripe) and also when you enter the atlas after starting a run the atlas should show the current position you are at in the sky, but it always defaults to the same location in the sky (Hard to explain without seeing it).  Neither is a deal breaker and just a couple interface gripes.

 

Also the Dwarf3 is incredibly small, I can carry everything I need in the one bag that come with it.  The dwarf, a small tripod, an extra battery for all night imaging, cables, solar filter in a bag about 10x6x8, amazingly tiny and light!  The S30 alone is near the same size if that is important to you.

 

I did own an S30 and currently an S50, the S30 just had inferior optics with bad stars in the corner, the S50 is much better, not alone to the aperture but just better optics probably due to a small field of view.  

 

I know many people don't expect amazing optics with a cheap smart scope and I'm not expecting Astro-Physics optics but at least a decent star across the frame.  

 

This is a shot from my Dwarf3 in B7 skies about 3 hours of time, I think that's a pretty nice result for a device that small.

 

 

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[martinontheroad]

Many thanks for all the responses. I can see there are many D3 folks on CN! You all are pushing me with sage advice e and experience towards the D3.

One aspect no one has touched on is the difference in Full Well Depth between the D3 and advertised S30 Pro. The 585 is physically larger and significantly more sensitive sensor. I’ve not used a D3 or any camera with a 585 sensor. Does the 585 convey a significant better capability over the 678 sensor in the D3?

[eyeoftexas]

Many thanks for all the responses. I can see there are many D3 folks on CN! You all are pushing me with sage advice e and experience towards the D3.

A very good reason to go with the D3 is you can get it now.  No telling when the S30 Pro will become available. By then, you’ll know if you’re happy with the D3 or need to sell it to get the Pro.  Good luck.  

Edited by eyeoftexas, 12 June 2025 - 10:16 AM.

[bradhaak]

One thing that occurred to me as I read what others (and myself) have written over the last six months, is the different targets of the S30, and the Dwarf 3. And because of the software, this will almost certainly apply to the S30 Pro, too.

 

The S30 and S50 (and probably the Pro versions) are very simple and suitable for beginners with no previous exposure to serious cameras or to astrophotography. They make no assumptions about user knowledge and make all of the exposure and imaging decisions for the user. Heck, they even decide which, if any, filter to use. You can override this, but you have to stop the image, change the filter setting, and then restart the image after losing whatever data you've already collected.

 

The Dwarf 3 is a much more customizable system. You have control of shutter speed, gain, etc. This is more advanced and lets the user play around and eventually figure out how to get the best results for their location and tastes. But, DwarfLab has also introduced the Auto-Parameter feature with the goal (I'd assume) of making the scope more accessible to beginners.

 

The D3s Auto-Parameter will probably evolve into something similar to the standard interface of the Seestar app, but I haven't seen or heard of any work to put an advanced mode into the Seestar UI. So I feel that saying the Dwarf 3 UI is more suitable for sophisticated users is completely true. But it looks like moves are being made to make the Dwarf UI suitable for both types of user.

 

Please note, I'm not saying one approach is superior to the other, because that depends on what the individual user is looking for.

[marvindj]

One thing that occurred to me as I read what others (and myself) have written over the last six months, is the different targets of the S30, and the Dwarf 3. And because of the software, this will almost certainly apply to the S30 Pro, too.

 

The S30 and S50 (and probably the Pro versions) are very simple and suitable for beginners with no previous exposure to serious cameras or to astrophotography. They make no assumptions about user knowledge and make all of the exposure and imaging decisions for the user. Heck, they even decide which, if any, filter to use. You can override this, but you have to stop the image, change the filter setting, and then restart the image after losing whatever data you've already collected.

 

The Dwarf 3 is a much more customizable system. You have control of shutter speed, gain, etc. This is more advanced and lets the user play around and eventually figure out how to get the best results for their location and tastes. But, DwarfLab has also introduced the Auto-Parameter feature with the goal (I'd assume) of making the scope more accessible to beginners.

 

The D3s Auto-Parameter will probably evolve into something similar to the standard interface of the Seestar app, but I haven't seen or heard of any work to put an advanced mode into the Seestar UI. So I feel that saying the Dwarf 3 UI is more suitable for sophisticated users is completely true. But it looks like moves are being made to make the Dwarf UI suitable for both types of user.

 

Please note, I'm not saying one approach is superior to the other, because that depends on what the individual user is looking for.

seestar_alp provides far more configurable capabilities with the Seestars.

[bradhaak]

That's true, but seestar_alp isn't from ZWO, and many (most?) users aren't interested in using a third-party app with a device that was purchased because it's all-in-one  config.

[martinontheroad]

Many thanks to all of you for your input. It helped to solidify my decision. I’ve ordered a D3 which should arrive sometime this week. Apologies in advance for the clouds….