Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Hardware requirements for near real-time EAA?

  • Please log in to reply
25 replies to this topic

#1 Hsewalia

Hsewalia

    Sputnik

  • -----
  • topic starter
  • Posts: 38
  • Joined: 13 Mar 2019

Posted 29 May 2020 - 05:57 PM

Hello everyone,
I’ve been considering getting into EAA for some time now but what really interests me is the idea of true “near real-time” EAA.
Is this even possible?
Is so, what equipment would I need?

Thanks,
Hsewalia

#2 astrohamp

astrohamp

    Vostok 1

  • -----
  • Posts: 146
  • Joined: 01 Jan 2020
  • Loc: Massachusetts

Posted 29 May 2020 - 06:29 PM

You might peruse the Night Vision (NV) threads.  Else a fast telescope, sensitive camera, and speedy computer processing.



#3 GazingOli

GazingOli

    Sputnik

  • -----
  • Posts: 35
  • Joined: 13 Oct 2019
  • Loc: Stuttgart GERMANY

Posted 30 May 2020 - 06:00 AM

... and aperture...



#4 alphatripleplus

alphatripleplus

    World Controller

  • *****
  • Moderators
  • Posts: 112,553
  • Joined: 09 Mar 2012
  • Loc: Georgia

Posted 30 May 2020 - 07:43 AM

If by "near real time" you mean a  few seconds, you can certainly take short sub-exposures of a few seconds and see the view "evolve" in real time as more and more subs are added to the stack every few seconds. That is what a lot of us like to do as the stack gradually shows a better view over time. 

 

If you are interested in something closer to a near "instantaneous" view, then a NV device may be what you are looking for.


  • ShaulaB and DSO_Viewer like this

#5 Hsewalia

Hsewalia

    Sputnik

  • -----
  • topic starter
  • Posts: 38
  • Joined: 13 Mar 2019

Posted 30 May 2020 - 09:37 AM

Yes. I’m interested in the short exposure real time stacking.
Is there a limit or sweet-spot as to how short exposures can be?
Can I go as short as say, 2 seconds?

#6 alphatripleplus

alphatripleplus

    World Controller

  • *****
  • Moderators
  • Posts: 112,553
  • Joined: 09 Mar 2012
  • Loc: Georgia

Posted 30 May 2020 - 10:13 AM

With a fast scope, and low read noise camera, you can typically stack sub-exposures of a few seconds, and with a mono camera the sub-exposures that you are stacking can be shorter than with a colour camera. So 2 sec subs are possible, depending on how fast the scope, the camera (sensitivity and read noise) and the target. However, if the overall system is too slow, you will find that better results will be obtained by stacking somewhat longer subs. For example, I usually use 5sec exposures with a sensitive mono camera and f/4 system, so 2sec is pushing it. If you look at what most people are doing with colour cameras, they are typically using longer than 2 sec sub-exposures. Of course, if you have a f/2 hyperstar system, 2 secs is probably fine.

 

Check the image gallery for details on the sub-exposures that people are using with their set-ups.

 

There are tools in SharpCap, for example, for estimating an optimal sub-exposure for a given optical system, but there are several other factors at play - sky brightness, sensor read noise, sensor pixel size, sensor quantum efficiency,  etc. The range of sub-exposures we see in EAA typically ranges from a few seconds up to a few tens of seconds. 



#7 Picheta

Picheta

    Sputnik

  • -----
  • Posts: 25
  • Joined: 28 Apr 2020

Posted 30 May 2020 - 11:19 AM

Hello Hsewalia !!! I am new too and I am studying which camera to get as I have never done EAA. Due to the opinions of users, I am considering buying either the 183 mc way or the 385 mc way for an alt / az frame, for this reason I am interested in short exposures and for what many people on this site tell me, I will use the software sharcap. What type of mount do you have? What optical tube do you use?

#8 Hsewalia

Hsewalia

    Sputnik

  • -----
  • topic starter
  • Posts: 38
  • Joined: 13 Mar 2019

Posted 30 May 2020 - 11:41 AM

Thanks Guys. This is precisely the sort of info I was looking for!
I have a Nexstar 8se with .63 focal reducer so f/6.3.
I have the Alt-Az mount it came with which I was able to get 13-second exposures before tracking degrades.
I don’t have an astro cam so that’s what I’m hoping to get first.
I don’t really want to exceed 13-second exposures so I’m not looking to change the EQ mount...just need to figure out the best settings for my given system and which camera would be appropriate.

#9 Picheta

Picheta

    Sputnik

  • -----
  • Posts: 25
  • Joined: 28 Apr 2020

Posted 30 May 2020 - 12:12 PM


I also use the Celestron Nexstar 8 se !! I also use a 0.63 focal length reducer like you. I have been doing photography with a Nikon D3200 camera, but I want to see more objects and better, it is for this reason that EAA seems to me the perfect option to be able to enjoy even more. If you want we can exchange sensations and experiences, since we are in a similar situation. The following week I hope to have decided which camera I will finally choose.

#10 Terrybythe sea

Terrybythe sea

    Vostok 1

  • -----
  • Posts: 129
  • Joined: 13 Feb 2020
  • Loc: Gaspe Peninsula

Posted 30 May 2020 - 12:16 PM

I'm just getting into EAA myself, so I don't have any specific advice, but these are a few topics I've been readng and learning from:

 

https://www.cloudyni...or-the-eaa-noob

 

https://www.cloudyni...ragement-thread

 

https://www.cloudyni...a-for-beginners

 

If you search for "live stacking" you'll find a number of others as well.



#11 DSO_Viewer

DSO_Viewer

    Apollo

  • -----
  • Posts: 1,075
  • Joined: 03 Jan 2016

Posted 30 May 2020 - 12:54 PM

... and aperture...

no not aperture unless you are observing strictly star cluster or very small objects. Aperture allows for the making the focal ratio faster while maintaining the image scale. You really want the fastest focal ratio as possible and if the objects you plan to look at are small then aperture helps.

 

Steve



#12 JohnBear

JohnBear

    Messenger

  • *****
  • Posts: 477
  • Joined: 08 Jul 2017
  • Loc: Sandy, Utah

Posted 30 May 2020 - 03:21 PM

I too will be following this topic. I'm in the process of learning and preparing to use basic (reasonably affordable and effective) EAA/video astronomy later this summer on two of my telescopes. I'm hoping to narrow down the better options in terms of usable cameras and software.

 

About a year ago I was trying to view Jupiter with with my old Nextimage 5 camera and SharpCap, but it was quite frustrating trying to find the right combinations of setting to get anything more that a blank screen or a bright glob image. Then quite by accident I hit upon a combination of gain and other settings that showed a pretty decent view of Jupiter on my screen and was able to capture a decent screen shot.  

 

This year I hope to take a more methodical and informed approach that will be more productive.



#13 Rickster

Rickster

    Apollo

  • *****
  • Posts: 1,262
  • Joined: 09 Jun 2008
  • Loc: NC Kansas Bortle 3 SQM 21.8+

Posted 30 May 2020 - 10:55 PM

Yes.  Aperture.  smile.gif



#14 Jethro7

Jethro7

    Viking 1

  • *****
  • Posts: 725
  • Joined: 17 Dec 2018
  • Loc: N.W. Florida

Posted 30 May 2020 - 11:16 PM

Hello everyone,
I’ve been considering getting into EAA for some time now but what really interests me is the idea of true “near real-time” EAA.
Is this even possible?
Is so, what equipment would I need?

Thanks,
Hsewalia

Hello, Hsewalia,

I do NV Astronomy, it was a total game changer for me and is one of the best devices I have bought for Astronomy. It is viewing in real time and it let's me see Nebulae and Galaxies from my moderately light poluted backyard. You use it just like a eyepiece.It does have a down side it is very expensive. This is one area that you will get what you pay for and I dont see anyway around it. The better the photocathode tubes used in these devices the higher cost ,as the specs get better the more you can see and the cleaner the views become. I paid around $4300.00  for my PVS 14 with specs that are much better than average, I know of some that they paid much more for insane specs. Do I think it is worth it. If my PVS 14 disappeared  I would save up and buy another one in a heartbeat.

 

HAPPY SKIES AND KEEP LOOKING UP Jethro

 

P.S. if you go th NV route  " DONT BUY OFF OF EBAY OR AMAZON "

Go with a reputable Nightvison Dealer. And when you buy tell them you want Astronomy specs.


Edited by Jethro7, 30 May 2020 - 11:42 PM.


#15 Dohko

Dohko

    Lift Off

  • -----
  • Posts: 3
  • Joined: 20 May 2020

Posted 31 May 2020 - 05:47 AM

To start in EAA low-medium-high cost, which cameras would be the most appropriate? forgive English, I use a translator. My telescope is a 2000/500 with GOTO, I have a laptop, synscan wifi tablet ... but I do not know which initiation or advanced camera is the most appropriate for this telescope. thanks in advance and i join this post to learn.

 

 

saludos



#16 roelb

roelb

    Surveyor 1

  • *****
  • Posts: 1,518
  • Joined: 21 Dec 2013
  • Loc: Belgium, Antwerp

Posted 31 May 2020 - 07:40 PM

See here for what can be done with a 6 SE + ZWO ASI290MM and short exposures:

https://www.cloudyni...-6-se-asi290mm/

 

and some images with a Evo 8 + ZWO ASI533MC-Pro:

https://www.cloudyni...iew_style=large



#17 glancey

glancey

    Explorer 1

  • -----
  • Posts: 57
  • Joined: 05 Jun 2019
  • Loc: Santa Ana, CA, USA

Posted 01 June 2020 - 09:51 AM

All the comments here have been on the imaging train - scope, reducers, cameras. Necessary, yes. But let's not forget that for EAA,  it's your computing power that can make or break the real-time experience. In fact the fastest scopes and cameras are for naught if you don't take into account the latency inherent in actually viewing your images. Just try focusing on an underpowered CPU and flaky network connection.

 

Most imaging cameras will deliver 4K, but how far are you willing to drop down your frame dimensions to a more manageable size due to slow processing power?



#18 Hsewalia

Hsewalia

    Sputnik

  • -----
  • topic starter
  • Posts: 38
  • Joined: 13 Mar 2019

Posted 01 June 2020 - 10:26 AM

That’s a great point. 
Are there any recommendations on laptop hardware specs for “fast” high resolution EAA?

For example, being able to stack 10-megapixel images every 6 - 8 seconds?

Also, most newer astro cams are USB3 so I assume file transfer time is negligible? (Provided of course that the laptop has USB3 ports as well).

 



#19 alphatripleplus

alphatripleplus

    World Controller

  • *****
  • Moderators
  • Posts: 112,553
  • Joined: 09 Mar 2012
  • Loc: Georgia

Posted 01 June 2020 - 10:51 AM

I am using a 2 megapixel camera (ASI290MM mini) with a 10+year old Dell Windows 7 Pro laptop with 4MEG RAM and Intel Core Duo T9600 @ 2.80GHZ processors and USB2 - not exactly great specs. I can live stack 1 sec subs all day night long in ASILive or SharpCap on my laptop with this set up with no latency. Now, if I had a 20 megapixel camera, it might be a different story.



#20 Rickster

Rickster

    Apollo

  • *****
  • Posts: 1,262
  • Joined: 09 Jun 2008
  • Loc: NC Kansas Bortle 3 SQM 21.8+

Posted 01 June 2020 - 11:09 AM

I use a 50ft active USB2 cable.  I haven't had problems transferring images from an ASI183 at the same time as an ASI290, using 1 second sub exposures (and sometimes shorter).  The cameras have buffers to support this, and Sharpcap is amazingly efficient.  Plus, if you do have trouble, most cameras support in camera binning to reduce file size.



#21 Noah4x4

Noah4x4

    Soyuz

  • *****
  • Posts: 3,550
  • Joined: 07 Apr 2016
  • Loc: Colchester UK

Posted 02 June 2020 - 09:57 AM

I am using a 2 megapixel camera (ASI290MM mini) with a 10+year old Dell Windows 7 Pro laptop with 4MEG RAM and Intel Core Duo T9600 @ 2.80GHZ processors and USB2 - not exactly great specs. I can live stack 1 sec subs all day night long in ASILive or SharpCap on my laptop with this set up with no latency. Now, if I had a 20 megapixel camera, it might be a different story.

Absolutely right!

 

I have a 16 megapixel resolution camera and it spluttered using a 7th Generation I5 with 4Gb RAM. It runs in true real time with a 8th generation i7 with 16Gb RAM. 

 

Much depends on the tasks. If you simply capture subs for later post processing you need less computing ooomph. But if live stacking 48mb short exposures at 1 second intervals, whilst simultaneously transmitting 4k UHD screen data to a computer indoors using Windows Remote Desktop/wireless you need loads of processing power and RAM.



#22 Rickster

Rickster

    Apollo

  • *****
  • Posts: 1,262
  • Joined: 09 Jun 2008
  • Loc: NC Kansas Bortle 3 SQM 21.8+

Posted 02 June 2020 - 10:41 AM

Absolutely right!

 

I have a 16 megapixel resolution camera and it spluttered using a 7th Generation I5 with 4Gb RAM. It runs in true real time with a 8th generation i7 with 16Gb RAM. 

 

Much depends on the tasks. If you simply capture subs for later post processing you need less computing ooomph. But if live stacking 48mb short exposures at 1 second intervals, whilst simultaneously transmitting 4k UHD screen data to a computer indoors using Windows Remote Desktop/wireless you need loads of processing power and RAM.

Just to be clear.  I don't simply capture subs for later processing.  I live stack.  I do not post process.  Don't have the time for that.  I have not had a problem live stacking ASI183 one second subs via a USB2 cable.  But then, I never had a problem using a wedge either.



#23 Rickster

Rickster

    Apollo

  • *****
  • Posts: 1,262
  • Joined: 09 Jun 2008
  • Loc: NC Kansas Bortle 3 SQM 21.8+

Posted 02 June 2020 - 11:51 AM

I suppose that I should add that I am running a 12 core Xeon workstation with 96GB of RAM and 2 Quadro4000 graphics cards feeding 4 monitors.  It is a data processing beast designed for 3D drafting and animation.  I don't how much help, if any, that it provides when I run 3 cameras through a single USB 2 cable, but it definitely isn't the weak link.



#24 Hsewalia

Hsewalia

    Sputnik

  • -----
  • topic starter
  • Posts: 38
  • Joined: 13 Mar 2019

Posted 03 June 2020 - 04:56 PM

Ok so from what I gathered, a relatively high end computer will be needed to process >10Mpixel shots at a high rate (say, 1 shot every 2 seconds)

Couple other questions I had:
1. Since I am shooting very short exposures (under 5 sec), is it worth spending extra for a cooled camera? Would thermal noise be significant in such short exposures?

2. For such short exposures as well, is there any need upgrading from my basic Alt-Az Nexstar GOTO mount?

#25 Rickster

Rickster

    Apollo

  • *****
  • Posts: 1,262
  • Joined: 09 Jun 2008
  • Loc: NC Kansas Bortle 3 SQM 21.8+

Posted 03 June 2020 - 07:05 PM

1.  Probably, if you have clearance for the cooled camera with your Nexstar.  Trying to read your mind here.  It is true that thermal noise accumulates as the exposure increases, and therefore, shorter exposures mean less thermal noise.  But, signal increases with time as well, and therefore, shorter exposures mean less signal.  Since the most important parameter is signal to noise ratio, the impact of exposure length isn't a significant factor in this decision.  That is, a cooled camera will give you improved signal to noise ratio at all exposure lengths.  The main advantage of a cooled camera is that it makes using darks practical, since your darks and lights should be taken at the same temperature.  Some people use darks and some don't.  Also, keep in mind that if you are getting a color camera, colored noise is much more obnoxious than mono (gray) noise.

 

2.  Probably not worth changing mounts, at least for now.  Short EAA exposures make Alt/Az workable.  Most folks here use Alt/Az mounts, despite the fact that changing to an Eq mount would solve many problems such as cord wrap, clearance issues, balance issues, field rotation, focal reducers, dew on the SCT corrector plate, etc.  OTH, Alt/Az is much easier to transport and set up.  I ran one for a while.  Lured by how compact they are.  Now it gathers dust.   But you may as well start out with your Nexstar since you already have it.  You will find lots of help and discussion here regarding how to make them work for EAA (because it takes a lot of discussion and help to get one working well for EAA).


Edited by Rickster, 03 June 2020 - 07:06 PM.



CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics