raadoo

Even with bad guiding, it's got quite a lot of potential.

I went ahead and had a play in PI & PS. Nothing major, just a few quick edits but other than a noisy red channel, data looks good to me.

30 minutes ago, vlaiv said:

Bit depth is rather inconsequential for planetary imaging as most imaging happens at 8bits anyway, and you'll be hard pressed to get saturation at planetary speeds with 10bit if you decide to go with higher bit depth.

As far as pixel size is concerned, here is F/ratio - pixel size relationship for critical sampling case:

F_ratio = pixel_size * 2 / wavelength

where pixel size and wavelength are in same units (meters, millimeters, nanometers - choice is yours).

Take wavelength to be either exact wavelength - like 656nm for Ha solar or if using Ha filter for lunar for example, or ~500-520nm in general case - for full spectrum / color imaging.

From above equation, we have following F-ratios for given pixel sizes:

3µm gives F/11.5

1.4µm gives F/5.4

2.9µm gives F/11.1

Two additional bits give only x4 more levels (2^2 = 4).

I may be mistaken but it seems that all three cameras above are colour; so you’re right that it’s 4 times more gradations … per channel. 4*4*4 = 64.

Bit depth is probably not that important for planetary but for lunar I would always go for the most bits I can get. If nothing else, it gives one some added flexibility in post before things start to visibly posterize.

Not sure what the SV89 is - I'm assuming you mean the 205?

Like @AstroMuni said, it depends on what kind of telescope you plan on pairing with the camera. When it comes to planetary, it all starts with the aperture of your telescope (focal length actually doesn't really matter as much as one would think). Once you know the aperture of your telescope, then you can look at what kind of pixel size your camera of choice should have. The equation does change if you plan on using a Barlow, though.

But, of course, you can calculate it the other way around, starting with the cameras. This should be a useful exercise if you're planning a rig from the ground up and don't even have a telescope yet. I've put together a quick table outlining the differences between Svbony's planetary camera offerings (or what little info I could find) and some examples of telescopes that match. This is all assuming no intention of using a Barlow, by the way.

If I were you, I'd go for the 305, based on the ADC alone (12bit is 64 times more colour gradations than 10bit).

The 205 may seem appealing because it's got more pixels, but those 1.4μm pixels are tiny and the 15fps much too slow for lucky imaging.

I'm interested, as well.

AM5 just went up on TS’ website. Seems like that initial $2000 price tag is maybe just for the US as TS list it at €2845 for the full price, with a €210 discount for preorders.

10 minutes ago, vlaiv said:

All fair points.

How about comparing it to something like iOptron CEM40 with RA encoders then? No need to guide, so it saves some weight and although mount head is not quite 3.3Kg, more like 7.2Kg is that weight difference really significant in portable setup (given all other components and their weight)?

I'm approaching this from strictly performance / price ratio thing rather than anything else.

For some (I imagine most?) people, yes, you're right, losing the CEM40's extra 4kg in mount + 4.5kg counterweight aren't going to be worth another €1000. For those of us with medical conditions that impose weight limits, every gram is worth it. 

You were one of the nice people who helped me make a decision in moving on from my AZ-GTi and the CEM40 was on my shortlist because it's one of the lightest in its class, counterweight included. But for me there's no denying that those 2kg less (what I saved by moving to the RST-135) make this hobby that much more enjoyable and allows me to take the rig out any time, all the time (bloody weather permitting, of course).

To be clear: I fully agree with you. A CEM40 (or even a 26) is plenty mount for most. 

Just now, vlaiv said:

That makes perfect sense, guide exposures need to be <1s and yes, infrared is the way to go in order to beet the seeing, but even in that case, such mounts are really in 0.5-0.8" RMS territory and that is fine - but not £4000 fine (at least in my book)

The way I see it, we are fortunate to have such vast choice in terms of mounts to suit our individual needs:

• For those who value portability and (lack of) weight, the RST-135 is unbeatable and its price tag is fair (I'm one of them).
• For those who value capacity and precision at long focal lengths (and are fortunate to have skies with excellent seeing) their 4k could be much better spent on a CEM120EC (or a G11T, or an EQ8R Pro, etc.).

If I may be permitted an analogy: Mercedes make a G Class (off road) and an AMG GT Roadster for about the same price (130k) but they serve vastly different needs for different audiences and I venture to say it'd be unfair to compare them to each other based solely on price.

5 minutes ago, vlaiv said:

Out of interest, what are the stats on RST-135 - P2P periodic error and guide performance?

(given that it approaches in price to a serious mount).

Around 30" - but just like the Hobym (and one can only assume both the Sharpstar and ZWO) - it varies depending on load and where it's pointing in the sky. 

In terms of guide performance I've only had about 30min to play with (it's been cloudy over here for the past 5 weeks straight) but it's been around 0.9" RMS on a night of poor seeing (5" - 6" FWHM) and intermittent clouds. As others have stated, guide exposures must be kept under 1s - fortunately, I can do that with my ASI120MM Mini and OAG through an FRA400 with reducer, without trouble.

Both here and on CN there are RST-135 users who have been able to beat the periodic error even at 2000mm by employing a good guiding strategy (and hopefully future AM5 users will benefit from this as well):

• < 1s guide exposures
• a guide camera with big pixels and / or binning
• infrared (or even a simple red) filter

On 22/12/2021 at 02:30, Kon said:

I popped out with the dog and I noticed that there was a very large halo around the moon, much larger than what I have seen before. A combination of light haze and nearly freezing conditions have helped. It looks really symmetric. I grabbed a quick shot with my mobile.

It never ceases to amaze me how in our time we have this vast scientific knowledge, at our fingertips, to tap (sic!) into and explain phenomena such as this in a most rational manner both superficially and in great depth, while our ancestors from millennia ago would have only their imaginations to work with and come up with fantastical explanations of spirits and otherworldly creatures or omens of good or bad times to come.

6 hours ago, wimvb said:

That answers the question I had. If ZWO would drop support of other mounts, they could as well discontinue the ASIAir.

What also surprises me, is that this is the second harmonic drive mount I've come across within this last week.

https://www.aliexpress.com/item/1005003408574030.html

I knew Sharpstar were coming out with their own [first] harmonic drive mount, but I wasn't expecting it to be more expensive than Rainbow Astro's! At least Rainbow Robotics have 10 years experience with these kind of drives. Neither ZWO, nor Sharpstar can make such claims.

Probably the only positive that everyone can agree on is that we have more choice in regards to mounts now.

@Hogarth over on CN, someone from ZWO posted to confirm that it will support ASCOM and conversely that the ASIAir will continue to support third-party mounts.

Quick errata: Yannick (Cuiv, The Lazy Geek) had the Hobym Crux, which he sent back. Not the Rainbow Astro.

You lot will be death of my wallet! 😄

Early Christmas present from the missus came in the very red shape of an RST-135! 🥰 Guess she was well sick of my indecision. 😆

We all love a good setup shot, so here's mine after re-cabling, troubleshooting and general tinkering:

Early reports are that everything works as expected with 0 hiccups and 0 problems.

The little RST-135 may not be premium in some people's eyes but having fondled the thing in and out for the past 24h, it definitely feels premium to me.

With no use for counterweights (there's no backdrive with my setup), this whole setup ended up weighing 2kg less than my previous, AZ-GTi + Berlebach Report, setup, so definitely a win for both portability and my back! 🤘

Big thanks to all of you for the help and planting the seed of the RST-135 firmly in my head. It was undoubtedly the right choice for my needs.

Fundamentally, all data is flawed by one thing or another. Even the best data we can acquire from Earth is flawed by the atmosphere.

Personally, that helps me psychologically because it means my data is just slightly messier (sic!) than others'.

And even if it's not the best outcome in the world, it's your time, effort, knowledge, skill and passion that were poured into making it, so never let anyone say it's bad, especially not yourself!

The second to last (R and B swapped) is really quite pleasing! 👏

Hi Daz,

I have the 178MC and it's an excellent performer if you're looking to do planetary, lunar and solar imaging.

For DSOs (nebulae, galaxies, globular clusters, etc.) however, I'd urge you to look at a cooled camera. The 178MC only comes as non-cooled and would yield significant thermal noise when pushed for long exposures.

If you want to stick with ZWO, the 183MC Pro is their least expensive cooled option and as luck would have it, I have one of those myself! It too is excellent, but not without its caveats (strong amp glow, needs a dew band if you live in high humidity locales, not the best QE or full well). Still, for 900 buckaroos, it's excellent value for the money.

I tried my hand at cleaning it up:

I intentionally didn't resort to either Topaz, Astronomy Tools Actions or any of the myriad of other add-ons one can employ with Photoshop and instead focussed on using just the default toolset. I also attached a screenshot of what the layers panel looks like, for reference.

The basic approach

Although noisy, the original image has some pretty clear separation between the Veil's nebulosity and the background. Initially, I thought this contrast may be stronger in the green channel, but it turns out to be fairly similar across all three colour channels.

As such, the approach here is to create a separation between background and nebulosity via a mask based on luminosity. So I grayscaled the original and used that as a layer mask to separate background from nebulosity. This mask needed further levels and a low powered Gaussian Blur to achieve the right level of separation.

Edits

With the background and nebulosity separated, I approached each of them in a different way, but using the same Adobe Camera Raw editor to keep it simple.

For the background I lowered the contrast and highlights, upped the shadows and blacks, desaturated slightly, lowered the texture, clarity and dehaze sliders all while adjusting the expoure slider to try and maintain the same black level as the original. I also ran a quick noise reduction while in the same ACR module. Essentially this step is about reducing detail in the background as the only detail to be found here is noise. One must be careful not to go hog wild on this, though - you're right that using a solid colour for the background would look off and certainly isn't in line with your (and mine) keep it natural philosophy.

For the nebulosity, I also resorted to ACR, but this time paying attention to just the Veil itself. So this time it was about increasing contrast, upping the highlights and lowering the shadows slightly, increasing saturation (slightly) in the reds, oranges, yellows and greens and reducing the saturation in aquas, blues, magentas and violets, increasing clarity and texture a smidge, all the while toggling the defaults (\) to make sure I'm keeping true to the original luminosity and colour.

I spent maybe 10min on this, so you can certainly expect even better results from taking the time but hopefully the way I approached it helps. It certainly doesn't help that I edited a compressed JPG 😆

A couple of weeks from now the Moon is going to occult M105:

And that got me thinking about what are some of the techniques that one could employ to image this phenomenon?

Clearly a single camera can't handle the fact that the Moon is just going to drown everything out. But what about having a lunar rig (Mak + planetary camera) do the Moon imaging while a DSO rig (Refractor + cooled DSO camera) chips away at M105 as it clears the Moon?

Could one then combine the two resulting images to [sort of] match reality?

Would even the best lunar glow / light pollution filters be able to cope with imaging a mag. 9 galaxy like M105 so close to the Moon?

Curious if anyone's tried anything like this before with and especially without success. 🤔

Looks like focus wasn't quite spot on coupled with guiding errors leading to the kind of polygonal look to the stars. The larger ones all show this kind of lopsidedness towards the top right.

With your setup especially (uncooled camera), you'll appreciate the kind of magic that calibration frames bring to the table. If not from a flatness of field point of view, then definitely in terms of getting rid of noise. Though you may very well already know this 😀

1 hour ago, vlaiv said:

I guess portability?

In that price range - GTD E.Fric is probably best option - except it is larger / heavier and can carry 30Kg.

Indeed, portability is key. On top of that, payloads over ~12kg photographic are not relevant to my use case (bad back, have my own weight limits to take into account).

1 hour ago, 900SL said:

Based on your list of requirements (which align pretty closely with mine), the Vixen. Although I'm oscillating between the SXD2 and SXP2 belt drive. 

I'm likely to buy one in the new year and for similar reasons. Portability, good QA/QC, reliability, good guided performance, and the Starbook 10 go-to seems like a great system. 

Portability is the big thing for me. I prefer to drive to dark sky sites

 

I'm finding it quite difficult to consider the SXP2...

On 18/11/2021 at 13:38, simmo39 said:

Great review, I luv mine but due to injury haven't used it much as I should have. I have got the focal reducer but have not real had chance to test it. Will post a review when that happens.

When you get a chance to test the reducer, compare star shapes with and without it. I'm getting severely bloated stars with the reducer on; it could still be something different (i.e. dew / frost) but it'd be worth hearing from others with the FRA400.

46 minutes ago, Whirlwind said:

It doesn't have to be and it really depends on what you want.  All I can go on is from my own experience.  I went from a CG5 - Vixen SXD - Mach1GTO.  In hindsight I would have probably been better to have gone straight to the Mach1GTO based on what I wanted to achieve at the time.  Nevertheless the SXD (although not planned) still provides a very useful 'holiday' mount as it is much more portable than the Mach1 (so I still have it).  The Mach1 is probably my forever, but not in an observatory mount.  When I get my own house in the countryside, in dark skies etc (I wish) then I will plan for an observatory mount....lol  Although if your current mount is on its last legs than you may be pushed into that earlier decision anyway (it really depends on why you want to upgrade).  But I do take the point that you can't wait forever otherwise you will never get anything!

That's exactly the kind of experience I'm looking to learn from, thank you!

9 hours ago, Whirlwind said:

The question I would ask is whether you can wait and build up some funds if you want a 'long term' mount.  It will open up more (and better) options.   The only experience I have is with the original SXD (different software) but found it a wonderfully light weight portable mount.  There were some known software bugs originally but I never came across these.  However I understand the SXP2 is much superior to the SXD2 option these days.  You've already noted the RA-135E is out of budget but if you could wait 6/12 months would that become viable?  I always find the worst feeling is "if I'd only been a bit more patient" etc.  

It's a fair point and one I've personally made to others in the past as well. We do need to define a few parameters before moving forward with this thread:

• Long-term Mount: I'm thinking 3-5 years. Past that, I'd be looking at what I call a Forever Mount (e.g. 10Micron)
• We can always extend the idea of if I'd only been a bit more patient more and more. And with it, budget. But a line must be drawn. So I'll extend that waiting to your proposed 6 months and up the budget to under €4k.

That being said, I have very little knowledge of that market or what's reliable / flaky, so any recommendations and ideas are very welcome!

7 minutes ago, vlaiv said:

I vote iOptron.

Do consider using better tripod like Berlebach instead of stock steel tripod for better stability, but check from portability point of view if it will suit you. I added Berlebach Planet to my HEQ5 and it made a huge difference.

Btw - you don't need guiding for planetary imaging.

@vlaiv You're one of the people here whose experience with their iOptron swayed me towards the CEM40! 😃 

I've purposely only mentioned the head weight for each mount above as I've been well sold on Berlebachs ever since I got my Report - but am planning on using an Uni for the new mount.

I am aware that planetary doesn't need guiding - that would in fact be one of the worse things I could do for my lunar images! 😁

After many hours spent tweaking and playing around with my AZ-GTi for the past year or so, I'm ready to move up to a more long-term mount and plead the wisdom of this fine group for some considered recommendations.

Things I care about:

• Equatorial GoTo
• Imaging, guided for both DSOs and planetary
• Portable, so low weight is paramount*
• Minimum imaging payload of ~10kg**
• Good track record of reliability, both hardware and software
• I'll continue to be using my AAP for a while so software compatibility is important
• < €2.5K

I've got a shortlist which looks like this:

But I'm very open to other options, so please do recommend!

* In an ideal world, I'd go for the RST-135 in a heartbeat. But it's near twice my budget so it's a non-starter, sadly.

** A C8 equivalent is the heaviest I'll ever put on it. Not because I don't want to go heavier, but because my bad back would have words with me if I would dare huck a chonker around.