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  #21  
Old 23-02-2018, 07:19 PM
astro744
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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_p...d=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.
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  #22  
Old 23-02-2018, 07:37 PM
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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

Last edited by xelasnave; 23-02-2018 at 08:05 PM.
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  #23  
Old 24-02-2018, 10:35 AM
raymo
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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
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  #24  
Old 24-02-2018, 08:52 PM
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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.
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  #25  
Old 25-02-2018, 10:22 AM
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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
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  #26  
Old 28-02-2018, 08:58 PM
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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
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  #27  
Old 01-03-2018, 01:27 PM
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Quote:
Originally Posted by Fox View Post
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

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.
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  #28  
Old 01-03-2018, 03:23 PM
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Quote:
Originally Posted by Fox View Post
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
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...
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  #29  
Old 01-03-2018, 04:37 PM
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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
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  #30  
Old 01-03-2018, 05:42 PM
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Quote:
Originally Posted by Fox View Post
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
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.
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  #31  
Old 02-03-2018, 01:29 PM
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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
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  #32  
Old 02-03-2018, 02:21 PM
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Quote:
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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
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.
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  #33  
Old 05-03-2018, 08:24 AM
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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
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  #34  
Old 05-03-2018, 10:31 AM
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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
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  #35  
Old 05-03-2018, 12:14 PM
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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.
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  #36  
Old 05-03-2018, 12:41 PM
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Quote:
Originally Posted by Fox View Post
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
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.
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  #37  
Old 05-03-2018, 01:40 PM
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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.... 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
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  #38  
Old 05-03-2018, 02:09 PM
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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.
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  #39  
Old 05-03-2018, 02:46 PM
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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!
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