Newbie advise for Planetary Imaging...

[Fox]

Dear Planetary image experts:

Well, I’ve decided to have go at planetary imaging. As someone who has NO experience in AP at all, I seek your expertise as a newbie, and have some questions I hope you can advise me on. As you can see from my signature, I have a Televue NP127is (f/5.2) as my main scope, and Meade LXD75 mount (yeah, the LXD75 isn’t so great, I know). I don't have a DSLR, although from what I can tell, the optimum equipment nowadays is via a dedicated planetary colour webcam (eg. ZWO series) and stack images. So, three questions to begin with:

1) Choice of webcam. I have my eye on the ZWO’s, either:
(i) ASI 120MC (about $220)
(ii) ASI 120MC-S (usb 3.0) (about $320)
(iii) ASI 224MC (usb 3.0) (about $420).

The 120MC seems ideal (up to 30 FPS) for the entry level newbie, and only $220. On the other hand, the 120MC-S for only $100 extra allows USB 3.0 for faster data transfer and up to say 60 FPS, thus potentially giving better resolution. As a third option, for an extra $200, the 224MC has this ‘low noise’ ability, allowing extensive short exposure stacking for more potential for deep sky images via a webcam. I am leaning towards to 120MC-S (for $320), but is the 224MC better in the long run ? ie. more multipurpose potential just in case I get the AP bug and would like to have a go at deep sky down the track...

2) From what I understand, with the NP127is, the optimum focal ratio should be around f/20. I therefore need say a 4x barlow to get this. Should I get the TV 4x Powermate ($490) to give f/21, or would a good 5x barlow (a lot cheaper than a Powermate) (ie. f/26) be “close enough” and quite acceptable ?

3) I don’t have a PC laptop at all (always been an Apple desktop owner). I’m quite happy to get a basic PC laptop with USB 3.0 for out in the field data acquisition for the webcam. I figure I can just transfer to my iMac and then use PC emulation from thereon to do the stacking, image manipulation etc. Is a PC laptop the most sensible way to go ?

I guess that’ll do for now in terms of just getting the equipment right. Am I on the right track at all...? All advice is welcome...

Cheers
Fox

[Fox]

PS: this is when I really miss having Bintel in Melbourne...

[Camelopardalis]

Regardless of scope, go for the 224. It’s just soooo much more sensitive with low noise. If you stick with the “small” scope, you’ll need all the sensitivity you can get. Give it a go.

What you will find is that the weather conditions, notably “seeing” affect the results you get.

Depending on your expectations, you may find you want larger aperture to get the results you desire.

[Fox]

Thanks ‘Dunk’, such info is invaluable for me. What do you think of f/20 vs f/26, is it essentially inconsequential overall? Eventually I intend to get a better mount, and yeah I also know an 8inch SCT or larger is the better way to go, albeit I can have fun with what I have at present. Fox

[Camelopardalis]

I wouldn't get too caught up with an expensive powermate just yet.

Planetary sensors typically have small sensors, so you will want to practice reliably getting the target on the chip before substantially increasing the focal length...as it gets proportionately harder!

[Fox]

Great advice, one step at a time, I like that approach and thinking. I’ll go with the webcam and laptop only, plus my existing 2.5x Powermate to learn the ropes first. Cheers Fox

[Camelopardalis]

Yeah there's plenty of time in the run-up to opposition to get in some practice...weather permitting :thumbsup:

[xelasnave]

I dont know if you are interested in the Moon but I think that is a good place to start.
Firstly it is easy to get on the sensor and you can learn how the gear works.
The stacking software is the same or similar I think ...registax I recall is what I used way back.
And we all want to jump in the deep end but you could get put off taking on the complexity.
I think of it like moto cross...many want to jump on a large capacity bike when the best approach is to start on a 125 cc and make sure you can ride it to the limit before you go to the next level.
And with most things getting the most from what you have is very satisfying.
I wish you luck and hope you can get some results that you are happy to share here.
Alex

[Fox]

Hi Alex, yes definitely will shooting the moon for starters.

One question about laptops, given USB 3.0, is there any minimum chipset I need to get so there’s no problem with webcam data acquisition ie. will those bargain basement $250 PC laptops listed at JB HiFi be okay, or should I aim higher? I’d hate to find that I’m not addressing the minimum specs for PC laptop properly.

Fox

[xelasnave]

I dont know but I asked specifically for usb 3 and was told it was usb 3 by the salesman and I found out only yesterday that I may have been sold usb 2.
I am so mad about it I have not been game to make sure that it is a 2 or a 3...my GZO works but ....I am fighting an impulse to go to the store and destroy the salesman and the shop...in otherwords a touchy subject at the moment...I am putting off confirming exactly what I have until I settle down...I am a calm person but when I find I have been lied to I simply lose it...I am happy I am 750 klms away ...

In any event I am not the guy to ask as I know nothing, but be careful and double check before you buy and when you buy.

alex

[sharkbite]

chipset will not likely have much bearing for data aquisition...
I have a "craptop" that runs a dual core brazos (read: not even enough grunt for a good tablet)

What is more relevant is disk speed....i replaced the HDD with a solid state drive, prior to which the avi capture fps was a joke
Plugging my 224 into the usb3 port now works like a bewdy for planetary avi - up to 60 fps.

For long exposure (DSO) work a HDD will be fine as there is not that much data coming from the camera

I don't do any stacking or image processing on this pc - i have to copy the files off
and let my desktop do the hard work.

If you want one machine to do the lot - a $250 special ain't going to cut it

[raymo]

Alex,
I think the piece of plastic in the socket that only allows you to insert the USB plug the right way up is blue as standard with USB 3, instead of the original black.
raymo

[xelasnave]

Yes I know and its not blue I had worked that out when buying a back up drive....and I should have bought my lap top from the same place..Casino Country IT...the slightly higher prices has come back again and again in service and help..really great shop...but I bought the lap top in Sydney at Harvey Norman at North Ryde.

I am fighting my anger.
If I go and confront the store and the salesman I know they won't do anything and start with excuses etc and at that point I will go off...As I said I am a calm person but when I lose it you may as well start counting the bodies...I know what I am capable of and I have come so close to overstepping the line it frightens me.
I chased a guy to the doors at the police station and I was so lucky he got to safety before I got my hands on him...

Its not nice but I have to keep away from situations that can escalate.

Another grand for another lap top and give the current lap top to my daughter is better than going getting locked up...

I am already seeing the bright side because she said she would like a lap top...

Alex

[xelasnave]

The bright side is this is onlt the second time in my life I have been conned.
The first time it was almost worth it.
This guy outside the office greeted me like we were old friends and I thought I knew him but could not place him. You get that in real estate with so many faces in your life.
Anyways he chats away, it was just before xmas, and he says I,m off to get some beer only $x a carton ..do you want me to get you one..sure and gave him the cash...never saw him again but I thought what a good act it was worth my loss to see a really good con man at work.

I thought he was good to con me.

Maybe the salesman made a mistake so I will leave it there...by the time I get back I may see him...Or write a letter to Harvey and vent...I would sue them but I have no evidence ...still I could make them suffer.


Alex

[sharkbite]

Alex - under Australian consumer law- you can demand a refund and they must comply. There is no need to get jiggy wid them.

https://www.accc.gov.au/consumers/consumer-rights-guarantees/consumer-guarantees#consumer-guarantees-on-products-and-services

specifically:

Products must also:

match descriptions made by the salesperson, on packaging and labels, and in promotions or advertising.

match any demonstration model or sample you asked for

be fit for the purpose the business told you it would be fit for and for any purpose that you made known to the business before purchasing..


In other words - if the salesperson said it was USB3 and it is not - they must refund the money.

I'd ring them up and ask nicely...
and have the ACCC website ready to quote from.


Having said that - i would find it strange if a modern lappie does not have at least one USB3 port - especially one costing a Gorilla.
What model of lappie is it?

[markbakovic]

Alex: check the little USB logo (the pitchfork image) next to the port: USB 3.0 will have an "SS" in front of that logo, the plastic blocker isn't always blue. On some laptops you'll have a mix of 3.0/2.0 (the toshiba I'm typing this on has 2x 2.0 and 1x 3.0, so I have to mind which port I use for what). Also important is that USB 2.0 works fine with the default self-installed drivers that windows sets up but 3.0 invariably needs the actual chipset maker's drivers to work (otherwise it behaves as 2.0), which might require a manual install.

Fox: Bintel had pretty decent deals on ZWO cameras round the end of 2016 when we needed one for a summer project, round 190 for the 120MM-S (monochrome 3.0) from memory if you want to hold out for a sale. The high speed USB is definitely the way to go: on a bright enough target (eg Mars is bright enough at opposition from memory) the extra framerate is really good at freezing the atmosphere (what you want for lucky imaging planets). What I'm talking about isn't 60vs30fps, because the real strength of these cameras is their arbitrary ROI (region of interest) capability. You define a box of the sensor around your target and the camera only reads those pixels, which it can do much faster than polling the whole sensor. With good tracking and guiding you can get a nice tight ROI and 200fps is possible with the standard software (we saw 500+ with custom interface).

At that speed you see the higher order contributions to wavefront error from atmospheric seeing though, so a scope much bigger than yours will not always give you better images: on a 16" LX200 we could actually see the sag of the primary over its triangular support on a star image.

My suggestion would be: ZWO USB 3.0 camera of your choice, avoid barlows (altogether even, but especially new ones) and start on the moon (big=easy targeting, bright=max framerate) and your current scope. Use smaller ROIs to push up framerate on native prime focus magnification until you find the limits of the camera combating the seeing, then if your pixel scale calculation shows you should be able to see finer detail consider barlows, then if the light runs out buy a bigger lightbucket.

Big (amateur) reflecting telescopes have a hard time matching with extra photons what they lose to good refractors in PSF quality, and the bigger your aperture the more you "see the seeing": at a good site the isoplanatic patch or size-of-atmosphere-that-only-causes-image-motion (no ripples) is rarely bigger than 30cm, so even an 8" SCT is pushing it unless you live at Siding Spring. Plus all the far-apart elements don't do you any favours with scattered light on a bright object like a planet (for deep sky much less of a concern, then diameter wins the day) - smearing out details the aperture should mathematically resolve.

For reference: Last year we chucked our 120MM-S behind a very nice Tec 140 (f7) and pointed it at Saturn, albeit on a **** mount (I had to manually track the target with the controller, for 3+ hours) and doing ourselves no favours with a 3nm Ha filter. I think we managed about 80fps and it was quite blurry (~30 degrees elevation, terrible atmospheric dispersion if we didn't have the filter). Meanwhile next door said LX200 0.4m f10 flying Canon's super high ISO camera with no filter was about the same image quality, albeit with more pixels covered thanks to ~3m extra focal length. I never saw the other team's raw data but from the screen displays of each setup I wouldn't pick the big SCT over the refractor, I'd just point the thing straight up :)

[xelasnave]

Thanks Shark bite.
I know from legal days I would have them and its seems the new laws are a revamp of the old law.
Evidence could be the problem.
But first I will establish if it is not usb 3 maybe they were out of blue on my run.
The computer is a Lenevo.
Pretty little thing.
Anyways if the worst case I need to move on and not let it worry me.
I often tell people the greatest loss is the stewing over things...I have lost time to that and realise that is the real loss.
Thank you for your input.
Alex

[xelasnave]

Hi Mark.
I will look see but when I connected the external hard drive it said something like...things would run better with a usb 3...anyways I will check and may even take it to country IT for confirmation.
I am getting over it.
Thanks for your input.
Alex

[xelasnave]

Hi Mark.
There is no little ss I am afraid.
Alex

[Fox]

Thanks guys! Alex, that's really bad about your laptop. But if you specifically asked about UBS 3., then by law they must supply USB 3.0 ie. goods must match your specific description you asked for. Consumer affairs would be on your side, but it may now depend how long ago this all happened... i.e. whether or not its now worth pursuing.

Mark, a lot of what you said has gone over my head, but i hope to understand, one day. At this stage, I'm only planning to use the laptop for acquisition, albeit it may not be wise for to go too rock bottom in model and price.

Fox

[astro744]

The image of your quality telescope will be only as good as your 5x Barlow. Get the Powermate, you won't regret it. As to which one others may chime in with a recommendation. Either 4x or 5x but note the 5x can amplify up to 7.7x depending on distance to sensor. 2x or 2.5x is probably not enough.

See http://www.televue.com/engine/TV3b_page.asp?id=123&Tab=_app

Note if you go the DSLR path you need to get the T ring adaptor for the Poermate. There are three, one for 4x, one for 2x and one for 2.5 & 5x. This places the sensor at the correct distance for the desired amplification factor.

If I had an NP127 I would only consider a Powermate.

[xelasnave]

Thanks that used to be section 18 of the Sale of Goods Act...The law is in my side but one needs evidence..I was in law for part of my life and I realise although the law says one thing its not always all that easy to get up... I never lost a case and that comes from having all the ducks lined up... but I just had an idea for you.

Do you have a dslr? (Edit I notice you dont)

That would be a good place to start as you avoid a lap top.

One of the reasons I held back from auto guiding which I now have but yet to do notwithstanding having bought the gear ages ago...was to not have to have a lap top in the field and to keep things simple.

The advatange of a dslr for me was you put in on the scope and it works all by itself ..no leads no lap top take it inside to down load power is within...I still have yet to control the dslr via the lap top. ..various difficulties have held me back from getting it all working...the point of coming to my dark site last week was to have it all working...lap top solar panel battery inverter small genny new mount two new scopes plus guide scope and cam everything really.
but the cloud now the rain...so still to have a lap top as a central feature.

Anyways even if you need to buy a dslr that may be a good first step.

I dont know how good they would be for planetary but surely you could take short exposures and stack...at the present I set mine for 30 seconds for deep sky, because of poor polar align when in Sydney plus it runs without the lap top...I have a remote but it will do that without one really..anyways throw the switch and away she ticks..so maybe set a dslr on short exposure for planets...maybe you can use their video feature...
Just a thought as it would forestall the purchase of a lap top plus you may care to do some deep sky.

I started way back to do planets but I got tired of it very fast...you do the Moon, Saturn Jupiter and Venus (because of its cresent) but unless you just keep trying to improve you , well at least I did, turn quickly to deep sky cause there are many more objects within easy reach.And it is easier in my view.
What do you think?
Alex

[raymo]

Markbakovic, My new Acer laptop has 2 USB 3 sockets[blue] and 1 USB2.
The 2 and one of the 3s have the traditional trident logo, and the other
3 has the letters USB and a battery arranged vertically, with the letters being partially superimposed on the battery. This is the USB socket for charging USB devices when the laptop is turned off.
I have three Laptops,[one old Toshiba from the earliest days of USB 3],
and a tower PC, and all have blue USB 3 sockets, so I think I can be excused for thinking that the blue was the norm.
raymo

[markbakovic]

raymo: oh no i didn't mean "you're wrong"; blue is indeed the norm, but I have seen "stealth" usb 3.0 is all I meant.

Fox: I realise I might have overexplained somewhat (to put it mildly), but my point was: just get the camera and laptop if you need one and start imaging, don't worry about another scope or barlows, televue or otherwise, yet. Once you're getting results with your perfectly capable scope you'll understand much more about what you might do to to improve those results, ie what to upgrade to.

Magnification is not the factor which drives how much detail you image, the diffraction limit of your optical system is. The lucky imaging concept (high framerate video, reject all but the best frames) only approaches the diffraction limit in most cases as anything better than the seeing limit often looks "so much better", zooming in more is not necessarily going to yield a better quality image, just a worse one on more pixels. As others have mentioned the sensors on these cameras are tiny, so putting eg Mars on one with ~1m focal length is not the simplest task already.

[Fox]

Dear all, thanks for all the extra info and debate, and I intend to go for the webcam first up. Alex, from what I understand so far, whilst a DSLR can be used for planets and requires no PC, the heavier weight and lower frame rate makes them not as good as a dedicated telescope webcam when it come to planets. Fox

[Fox]

Fox here again with some laptop questions:...

1) to those of you who do planetary webcam work, is there any advantage to getting a laptop with a backlit screen ? i.e. keys light up in the dark. Would it be a big disadvantage if the laptop only had a non-lit screen ?

2) is 32GB storage enough, since I believe Windows 10 may take up about 20BG, leaving only ~10GB for user storage. Is that enough for the ZWO webcam software and Registax ? Should I really be looking at 64GB instead?

thanks
Fox

[sharkbite]

This is my Opinion and has the right to be challenged by the more experienced...

Backlit keys might be a disandvantage as the glow might wreck your night vision. When using sharpcap, i set the screen to "night mode" which makes
everything red. the glow from the screen is enough to see the keys. Not that you need to do much typing in sharpcap anyway.

Even 64gb is not a lot when capturing AVI.
I easily fill my 240gb SSD in around 2 hours of capture.

P.S. one thing using the 224 that i find harder than when using an SLR....
the SLR works just like an eyepiece when acquiring and focussing on a target, making this job a fair bit easier.

[Camelopardalis]

1) Backlit keys - irrelevant, besides ease of use (which may be very relevant!). Solar system objects are very bright compared with DSOs and consequently whether you image the planets/Moon from a dark site or the CBD, it is unlikely to make any difference....there is no dark adaptation involved, unlike DSOs.

2) Planetary imaging can gobble up disk space like it's going out of fashion...I can easily capture 100+GB in an evening without spending too much time getting eaten by the mozzies...

[Fox]

Thanks guys, looks like back lit keys are not preferred, and at least 64GB is the obvious way to go... Perhaps getting 2 x USB 3.0 ports and external hard drive drive is another option.
Cheers, Fox

[Camelopardalis]

You've got to choose what's best for you, if the backlit keyboard can be switched off for dark site visits, then why not? Even better if it lets you adjust the colour.

External drives can work...it all depends on resolution/frame rate that you intend to image at...to estimate, multiply the horizontal by the vertical (in pixels) to get the number of bytes required per frame, then multiply by the number of frames per second to get an idea of the throughput you'll need for any storage.

In reality, it's probably not as bad as the estimate, since when imaging Jupiter/Saturn/Mars you don't absolutely need a lot of dark pixels around them, so you can be "economical" if need be to keep your throughput under control.

[Fox]

Another quick question... with the webcam, with the typical exposures needed for planets, how big would a single typical .avi file be? And what about Deep Sky using the webcam, how large are these files typically? Thx, Fox

[sharkbite]

the 224 has a 1.2 Megapixel sensor....so roughly 1.2 Meg for photos ;-)
Since DSO exposures run at maybe 20 to 120 frames per HOUR.
this wouldn't fill even the tiniest of HDD

for .avi it is a bit more complicated...it depends on the colour depth
and fps which both influence the data rate....

i shoot using the 'RAW16' setting and with planetary i have had 'er up to 60fps.
This filled my 240G SSD in just over an hour....
Raw16 has the biggest uncompressed colour depth,
and the maximum fps is determined by how bright your target is
vs how much gain you have to apply to get a decent result.

I typically try to capture 4000-6000 frames for any planet -
although you start to get smudged details after a minute or so of captures.

[Fox]

Update: my ZWO camera is on back order. I just got an HP Pavilion x360 Intel Celeron 11.6 notebook, 2x 3.0 USB and 500GB HDD. Yeah, pretty low end but I reckon it will do, from all your posts it seems like that drive space is a consideration. Registax 6 installed.

Next question, what image enhancing software should I be loooking at. I cringe at the idea of getting full on Photoshop, although I may have a very old PC version somewhere. Cheers, Fox

[xelasnave]

Maybe get an external hard drive.
I picked up 2 terrabytes for $80 I think.

You may get a surprise how fast you use up disk space..

However its great to hear you are making steps in the right direction.

Thanks for sharing your progress.
Alex

[Camelopardalis]

Fox, I've captured with several machines over the past few years and found the specs to be largely irrelevant so long as it has USB 3 and fast enough storage. SD cards and any internal "MMC" storage generally isn't fast enough, or large enough, to be useful.

Even a USB 3 hard disk like Alex suggests is a better way to go when you outgrow the internal storage.

[sil]

I'm going to bet that laptop will be poor choice with the camera you chose. HDD will be a problem and likely the cpu too. Being HP it'll probably come preinstalled with a bunch of crap that is always running in the background and wanting to phone home and basically hogging the cpu which will interrupt disk access, with a HDD instead of SSD it will be a factor even if you buy an external SSD to record to (which you should anyway, its never efficient to record to the same device the operating system is running from).

Software: capture with FireCapture or SharpCap
preprocess video with PIPP
Image stack and enhance with registax or AutoStakkert2

All free and will get you final images. Grab GIMP as Photoshop alternative if you think thats what you need.

[Fox]

Thanks Alex and Dunk, I can always add external disc space if and when needed.

Sil, such conflicting advice - I cross my fingers that I haven’t done my cash for nothing....:question: I am a complete novice, if the CPU and/or HDD are not good enough during webcam acquisition, will there be obvious hiccups and symptoms that will tell me? Will it stall or give error messages during acquisition? I realise that when it comes to processing after acquisition, the laptop may be a bit on the low end, but if that happens my backup will be to simply transfer the data to my big iMac and run from there, ie. Windows emulation. I have no intention in using the laptop for anything else at all, no Office, videos, browsing, music, email, apps, messaging at all, nothin, zilch...! I have a massive bias against MS, Windows and PC’s in general. I get the idea that over time they can just accumulate crap from anywhere which plays havoc on performance... so I’m very very wary of never exposing the system to anything other than what I really need... But thanks for the opinion and advice all the same, it’s all valuable to me....

Cheers, Fox

[Merlin66]

Just an observation on newer USB3 and USB2 ports.
My laptop runs great with the USB3, but I also have a camera (DMK51) which will only run at fast frame on USB2.
When I plug it into the USB3 I get 7.5 fps (normally 15 fps) but guess what...when plugged into the USB2 I get exactly the same result - 7.5 fps

The supplier thinks it's something in the BIOS....
Another suggestion was to disable the USB by looking for "USB3 XHCI" in the BIOS and remove it.
I haven't tried that - yet.

[Camelopardalis]

Later versions of USB have become less reliant on the CPU.

Pretty much any recent CPU will get you going. Last time Mars was around I was using an 11” Lenovo with an Atom chip, 2GB memory and USB 2.0. Hence my previous reference to getting creative with the ROI (region of interest) to keep the throughput and consumption under control ;) but note that the CPU and RAM weren’t limiting capture, only the storage. You don’t need to be capturing large slices of black sky unnecessarily.

If your disk can’t keep up (unlikely, if it’s internal) then you’ll just drop frames...SharpCap has a counter for this at the bottom of the screen. To minimise this, I capture in 8-bit SER format, as it’s basically just a raw data stream from the camera. There is practically no overhead in writing it out, and since I typically capture thousands of frames at a time, I’m not going to lose any sleep over a couple of hundred dropped ones.

I’m not saying this should be your approach - it’s up to you to find your own way - I mention it in case anyone finds it useful, as someone who enjoys planetary imaging myself (and I don’t profess to be an expert!), I encourage you to experiment and see what works well with your kit. The Moon is around a lot of the month and is always a good target to practice on.

IMO the bigger challenges are getting the darn things on the chip...and the biggie we can’t control, the weather!