It's time to go Mono. Help please?

[JamesF]

I'm no genius.  I've just always been happy with maths

Mind you, I've been trying to get my head around Fourier Transforms of late having never done them at school and it's really hard work.

James

[Davey-T]

Thanks James

Only got as far as quadratic equations then had to leave to work down the pit to support my mother and six siblings 

Anything useful that I did learn has been long forgotten.

Did read something a while ago that gave a reasonably lucid explanation of FFT but can't remember where it was now.

Dave

[riklaunim]

ICX445 is good, but that Skyris price is kind of kill it There is either cheaper PGR Chameleon/Atik GP or other sensors like the much faster and bigger IMX174 or incoming cheaper but slower IMX249. Aside of that IDS/PGR have E2V CMOS sensors cameras that are quite cheap, the sensor is quite big (but pixels aren't small so not many).

So if you don't want IMX174 imaging killer (Grashopper 3, Basler, ZWO upcoming camera), then cheaper upcoming IMX249 (PGR) could be an option, or currently available e2v based cameras (IDS, PGR Blackfly...) or ICX445.

[Luke]

One thing I intend to check out before getting a new camera is, is there any real benefit to getting a cooled camera? I see the iNova cameras have cooling (SCS Astro stock these, I am not sure who else does).

It doesn't seem obvious that cooling is really needed for solar, but then again, noise seems to be the wall I constantly hit when using deconvolution, but I don't know if cooling would help out there. I don't e.g. know whether the noise is more to do with the decon than noise in the capture

Sorry, Iain, I am not helping   I will try to make up for that by suggesting, forget the DMK41, it's an old camera for new camera money in my view. Faster frame rate can only help in my view - though for me about 50 to 60FPS is about as fast as I could use with my 'dark' Quark (close to 0.3A?) as it needs a relatively long exposure time. I never feel like I have too many frames. Just my opinion, it obviously is a very capable proven solar camera so of course the frame rate is okay. The DMK41 was an obvious choice a while back and many great imagers had one or still have one, so it's no surprise you see so many good images. I shall go into hiding now as the DMK41 was getting much love above!

[Stardust]

Hadn't realised buying a camera was such a mine field.

Ethernet sounds like it has it's own set of problems.

Might stick with my cam until I can see some blackfly images to compare with mine,

I know it should be better but by how much ?

[Stardust]

Which camera would people recommend for my scopes on lunar and solar. Mainly a meade 127 triplet a tv 85 both around f7. The pronto does well and have the option of a zs66 and tal100rs. Quark for solar and barlowwd up for high resoltion lunar work. I'm thinking of a blackfly but would go to a flea if justified. I see the blackfly comes in different flavours so assume they will be best one for me.

[riklaunim]

Cooling isn't necessary unless you put the camera in full sunlight and it gets very hot

Might stick with my cam until I can see some blackfly images to compare with mine,

Which model of Blackfly?

Which camera would people recommend for my scopes on lunar and solar

The same as mentioned before - depends on your budget.

[Stardust]

I was looking at the ones offered on the astrograph.net web site icx693 icx692 ev76 the flea is icx618 can't afford a grasshoper

[riklaunim]

ICX693 is more planetary, ICX692 more lunar/solar (relatively slow even with ROI - so not a speed champion on planets), the e2v can do both, but can be more noisy on max/very high gain or when very hot And any e2v camera must have a switch for rolling shutter, as global shutter on those sensors is very bad.

[DrRobin]

Hi Iain,

Only just seen this thread and seeing that I have been mentioned several times I think I should offer my two pence worth.  I bought a DMK41 a couple of years ago, Alexandra and everyone else who was any good used one, so that was good enough for me.  That was until earlier this year, I bought a ASI120MM for mono planets, tried it on my Lunt, not really expecting it to work well, but was surprised.  There are more Newton rings with the ASI120MM than with a DMK41, but as I push up the magnification with a barlow my DMK41 shows some rings.

Now here is the interesting bit, the Newton rings on my ASI120 are closer together but the edges are softer than on my DMK41 and as such, letting the image drift around a bit on the frame usually sorts out most of them.  Since doing a proper side by side comparison test I haven't used my DMK41.  Even with my Quark where Newton rings are a real problem with both cameras, my ASI120MM is still easier to deal with, captures faster and will run in 16 bit (12 bit actually), so it is still my camera of choice.

I bought a ASI120MM-S when they were first released to beta testers.  It is faster and slightly more expensive than the standard ASI120MM, but apart from that there is no difference.  Given the samll price difference and if you have USB3.0 I would go for the -S model.  I will keep both, my night time rig on the planets can use a ROI to get 60 fps on USB2.0 and I haven't fitted a USB3.0 card to the obs PC yet.  I will keep on using the -S for solar and keep the DMK41 as a door stop, sorry I meant for mono imaging, just don't know what at the mo.

I haven't any personal experience of the PGR cameras, but I did look long and hard at one and then after courting opinion on here went for the ASI120MM, but remember that was for the planets and not for solar Ha.  I think there are better camers for solar Ha than the CMOS based ASI/QHY, but they represent great value for money and I think you will be pleased.  If however, your budget and laptop will support something bigger with more pixels and a CCD then go for it, it will probably give better results with less issues in your Lunt.

I hope that helps?

Robin

Robin

[Iainp]

Hi all, I'm ready to buy!

Robin, thanks for your info too. Apologies; I only just spotted your post now. So:

Leaving aside the DMK debate...it seems the ASI 120MM would be a good value for money option, but I don't need to worry about price too much, as long as I don't go too far over the £500 mark.  And getting full disc imaging is not such a priority either. Which kind of suggests that the ICX range would be a good, safe bet? 

Ok, but which one. Thanks to Rik for v detailed information.  Rik, I'm assuming by saying that, compared to the ICX445, the Skyris 'kills it', , you mean that the price of the Skyris is too high, rather than it kills the 445 by being so much better than it!   "The ICX445, then, would be fine it seems, and it's on Astronet at £309, which is well within budget. I'm assuming I'm looking at the right one: (on Astrograph.net) 

Point Grey Chameleon USB 2.0 Camera (ICX445 Mono) 3.75µm

And the other one mentioned is the ICX692:

Point Grey Blackfly GigE Camera (ICX692 Mono) 4.08µm

Which, confusingly, is also at £309! 

So, credit card in hand, do I go for the ICX445? As I say, I'm happy to go up to £500+ but can't go all the way to the next level, eg IMX 174 at nearly a grand.  If the 445 does a good job, it's very reasonable price-wise, and by not breaking the bank this time round, I'm closer to being able to DS the Lunt, and I can always sell the 445 and upgrade in future.  If I get a couple of positve responses I'll go for it! Thanks as always for the help, Iain 

[Stardust]

Have you talked to Rupert at Astrograph, he is extremely  helpful for which camera would be most suited to your scope. I've just fitted a gigE card to my pc, couldn't have been easier and went with an EV2 Blackfly on his recomemdation. Waiting for a gigE switch and cables to hook it all up.

[Iainp]

Thanks, I'll call him tomorrow 

[Iainp]

  I contacted Rupert at Astrograph (Thanks for the suggestion David).  What a top guy! He gave very detailed advice by email then spent a long time on the phone walking me through the options. His suggestion is  the Point Grey Blackfly GigE (EV76 Mono) 5.3 and it's well within budget at £325.  The only problem is that it turns out my laptop will only give 15 fps with this camera.   I'm now wondering if the Skyris 618 would be better, as I can get 120 fps with this using my existing USB3 connection.  It's a more expensive camera but presumably the increased frame rate would be a big advantage? I'll put this question to Rupert too, but any thoughts in the meantime? Thanks. 

[riklaunim]

100 mbit Ethernet causing the slower FPS? 15 FPS at full frame is still acceptable for moon/sun. That camera can use a smaller subframe and go faster (for planetary imaging). That will give you probably around 50-60 FPS on small frame (speeds around USB2). Only very bright planets like Mars or Venus in IR will be bright enough to use that 100-120 FPS from easily/efficiently. You could also try USB3 GigE adapter - if it's good it should work (faster than 100 mbit).

[Stardust]

With our seeing I think a higher frame rate is better. My qhy only gave 14fps at full frame rate. Whilst the video looked like good asi2 could only give me 70/1000 frames at times. The seeing was morphing the chromosphere so although looked sharp it was different sharp if that make sense. I could have used a smaller frame size but it's already a small chip. The blackfly covers a lot more area and dose a good job on the moonso very happy with it.

[Iainp]

Thanks very much for the advice.  The exact reason why it's only 15fps is rather compicated (for me). Rupert took me throught the settings on my computer to discover that it's the best I can get.  It's interesting that restricting the ROI will make such a difference to increasing the frame rate. If I can get 40+ pfs that seems very good? Then again, I do like the very fast frame rate of the Skyris .I have the 618  camera and it's really fast, just a shame that it's colour...

So, the debate continues. How important is the frame rate? Do I go for a excellent (and lower cost) camera which is not ideally suited to my laptop, or the more expense and (smaller chip?) but much faster Skyris??

[Iainp]

PS regarding: "You could also try USB3 GigE adapter - if it's good it should work" I think that's what Rupert was telling me wouldn't work on my computer. Can't remember the details, I was getting rather confused by then (which is not a reflection on Rupert's fantastic help and guidance, but on my minimal technical knowledge and IT incompetence....)

[Luke]

My thoughts on the Skyris 618 is I'd find the resolution, which I think is 640x480, a bit small for solar given your nice budget for a camera. The chip is a fair bit smaller than the Blackfly, looks like you would need about four tiles or more with the Skyris to capture the same area as the Blackfly gets in one hit. Also to keep in mind is that four tiles is possibly going to take four times as long to capture. Sometimes you run out of clear sky sooner than you'd like. Would the 618 really work out being faster?

The highest frame rate you can use will depend on your gear and how long the exposure time is. E.g. with my Quark I use an exposure time of about 40ms sometimes, that limits the max frame rate to about 30FPS, so a 120FPS camera would be largely wasted on me. Similar for lunar with my SCT, at the mo I love using a 1.6x or 2x Barlow and again that's nudging exposure time towards allowing a max frame rate of around 30FPS typically.

That's not quite true because I could increase gain to shorten the exposure time but I like to avoid gain if possible, it increases noise and although stacking helps to reduce the noise I'd rather avoid the increased noise in the first place if possible.

My single stack SolarMax 60, on the other hand, could take a much faster frame rate than 30FPS as the exposure time is only about 1ms at prime focus!

For me I like to get around 900 frames upwards if possible per solar movie capture. That's just about the number of frames that I typically find under my usual seeing (less than ideal) works quite well for me the way I process, fewer frames and I tend to hit noise earlier while sharpening, limiting how much detail I can get.  I record typically for about one minute so that means frame rate of around 15FPS keeps me fairly happy, but the more frames the merrier, especially if the seeing is not that great and you have to throw away a large percentage of the frames.

Now all this talk of fast mono cameras should not put anyone off if they have a camera that is supposedly not ideal for solar or have a tighter budget. David has taken some superb H-alpha pictures with a colour DSLR, mono is better but the best camera is the one you have.

If you can spoil yourself, for me mono camera around 30FPS ticks a lot of boxes. Faster can't harm if your gear can take advantage of it, but I would say think twice before going smaller as well as faster, 30FPS is no slouch already and I would probably rather have 15FPS than halve the height and width. That's just me anyway. Good luck deciding, I found it very tough picking a camera!
 

[Iainp]

Hi Luke, thanks as always for your detailed response! I'm pretty much ready to get the credit card out. 

 Rupert's reply is characteristically detailed too, and I'm copying it here with his permission. Also, it seems I got it wrong when I said the EV76 was 15fps .... 

  

1 - The FPS quoted for a camera is the maximum speed it can run at if the whole sensor is used to capture data. The FPS limit is basically a limit on the chips processing and how much data can be processed in one go. The 618 quotes 120FPS but it's only a 1/4" sensor of 648x488 pixels. The EV76 is more than 4x the area and 1280x1024 pixels. So you have 0.3MP vs 1.3MP. Crop the frame of the EV76 down to the size of the 618 and you will be seeing 120FPS if not more. Bear in mind that to achieve 120fps needs an exposure of 8ms (0.008s). That’s an exposure length more typical for solar imaging. Planets are too dim to get anything like this. IR imaging is not going to work either as a cameras QE (sensitivity) drops like a stone in the IR band so you need longer exposures. In any case even a camera with a global shutter can display artefacts when ran at very high speed so the general advice is avoid it.

2 - High frame rate is not something you can just have. The correct exposure is far more important than high frame rate. If the correct exposure means you need to expose for 0.1s (100ms) then you will only get 10FPS regardless of what the camera is advertised to do. Underexposing to get more frames just reduces dynamic range and contrast. Once detail is gone, you can't get it back. If long exposures mean more time is needed which brings about the possibility of motion blur caused by a planets rotation, then use something like WinJUPOS to derotate the capture.

3 - The idea behind high frame rate is twofold. Firstly it makes use of something called 'lucky imaging'. As I am sure you know, variable seeing means you get those periods of observing when everything's a bit soft then it briefly snaps into sharp focus. By capturing those 'moments' of clarity and separating them from the mush, we can reduce the effects of seeing. The second use of frames is that stacking them reduces noise and increases contrast. However it is bad to pursue high frame rate exclusively. Turning up the gain on a camera to permit a higher frame rate will add far more noise than stacking less frames. So frame rate is nice but if it comes down to more exposure length or more gain, opt for exposure.

4 - A better camera (regardless of the chipset) will have lower noise and better dynamic range. A chip does not a camera make. I'm not going to comment on the merits of certain brands but let's just say that some planetary cameras that are quite expensive are also considered quite poor. The EV76 chip mentioned does not shout out at you from looking at the specs (apart from the colour chip which has exceptional colour balance), but when used for imaging it produces results which just look 'right'.

5 - Using a 100Mbit connection with a GigE camera will limit the maximum frame rate, simply because it can only pass so much data. However the EV76 should get up to about 30fps via 100Mbit not 15fps as quoted. The Sony ICX692 (also 1.3MP) drops from 30 to 15 via 100Mbit. You can also improve speed by binning. If supported, binning pixels increase sensitivity but also reduces the data overhead. The effectiveness of this depends on the scopes resolution though. A big aperture and long focal length dictate bigger pixels to sample correctly. A 4µ pixel on a C11 with a 3x Barlow will just look soft. Binning to produce an 8µ pixel will look sharper and improve sensitivity. On a small scope it would just look 'blocky' (under sampled).

6 - USB3 to GigE adapters might work and might not. I have not tried one yet. I suppose for £20 its worth a punt. We have tested USB2 to GigE and although they claim to support jumbo frames up to 9K, they don't. Probably because USB2 is not as fast as Gigabit Ethernet. USB3 is a minefield and the speeds possible depend mainly on the PC hardware. It also can suffer from driver confusion. Our recommended cameras dedicate the USB3 bus to the camera exclusively. i.e. you cannot use the port for anything else.

[DrRobin]

Hi Iain,

15 fps is quite slow by modern standards. My DMK41 only outputs at 15fps maximum and if I ever use it now, I can't believe how long it takes to get 1,000 frames, my standard number these days. The only other thing I find is that the longer you are imaging one pane, the more likely it is that it won't stitch as the fast changing features can sometimes blur and cause problems.

My ASI120MM (USB2.0) will run at full frame in 8 bit at 30 fps. An ASI120MM-S (USB3.0) will run at 60 fps at full frame in 8 bit and 30 fps at full frame in 16 bit.

Is there a specific reason why your PC will only handle 15 fps? Is it the interface you are going through? Is it only USB1.0 or something?

There doesn't seem to be much point in getting a camera that runs faster than your PC will cope with unless of course you are going to upgrade your PC in the near future?

Robin

[DrRobin]

USB 1.1 gives speeds up to 12Mb/s

USB 2.0 gives speeds up to 480Mb/s

USB 3.0 is designed to run up to 5,000Mb/s

A 1280x1024 chip will produce 10Mb/frame. So USB 1.1 can do about 1fps, USB 2.0 can do 48fps and USB3.0 can do lots more. The only trouble isthis is based on the interface running flat out, which it never does, hence we get around 30fps on USB2.0 and then the camera chip is usually the limiting factor for USB 3.0 and limits to around 60 fps for a full frame.

USB 2.0 is fairly reliable but there are compatibility issues with USB 3.0. Some camera manufacturers maintain a list of host pc USB controllers that are known to work and if there are any issues, but many just have to suck it and see.

USB to GigE adaptors may also suffer from compatibility issues and if only have USB 2.0 then you are limited to around 30 fps.

I hope this helps,

Robin

[riklaunim]

Does your laptop have USB3 (there must be a reason why GigE on USB3 wouldn't work on this laptop)? If not then even Skyris won't give you full speed. I had the e2v EV* based camera on USB2 (and few others with ROI-speed feature) and the max framerate depends on the frame size - the smaller, the faster ICX618 is good for planets, small for moon/sun. If you don't have GigE or USB3 then pick a USB2 camera. If you have working USB3 then you can look at USB3 Point Grey/IDS Imaging/(Basler) cameras. There are also USB3 Ximea cameras, but software support is limited to Sharpcap at some beta-stage (but it worked for me some time ago).

And bad seeing doesn't need very high FPS. If the planet is bright enough (most of them isn't) you can choose between recording at max gain and shortest exposure (fast) or lower gain and longer exposure at slower FPS. The faster option will catch more frames but their signal-to-noise ratio will be lower and much more will have to be stacked. Slower FPS recording on lower gain will have higher SNR so less frames have to be stacked for the same effect. This can be tested on Mars and to some extent on Jupiter. In my case - I recorded Mars at ~60 FPS instead of > 100 FPS as it gave me better results (but some people found >100 FPS option better for their processing chain).

[Montana]

Can I ask why you are trying to buy a GigE camera? it is very old fashioned, my computer doesn't even have one and it is 2 years old. The way to go forward is USB3 and buy a better computer with a powered USB3 on it to go with it. You want a large chip and around 15-30fps is ample for the Sun.

Alexandra

[JamesF]

I wouldn't describe GigE as old-fashioned really, Alexandra.  Cameras using gigabit ethernet have been around for a while, sure, but gigabit ethernet itself is still a technology people are actively working with.  It's not the dead horse that FireWire appears to have become (at least in a domestic environment), for example.  In fact the impression I have is that  the likes of Point Grey are producing even larger ranges of GigE cameras these days.

That said, I'm really not convinced there's a benefit as far as increasing frame rates is concerned in using such a camera for astro-imaging unless your imaging computer has a gigabit ethernet network interface.  I think going directly to USB3 probably makes good sense in that case.  In my experience USB to ethernet conversion has always been a bit ropey and I'm struggling to convince myself that massively increasing the data rates is going to improve the situation.

James