EAA newbie question

[Franklin]

Looking into enhancing my visual astronomy due to light pollution and have picked up a camera for EAA, not astrophotography.

It's an Altair Astro Hypercam 183c (fan-cooled version) and was wanting some advice on laptop requirements. My current laptop is just a basic Lenovo "notepad" type and from what I've been reading online will probably be too slow for live stacking with this 20mp USB3 camera. I'm going to get a better laptop which I will use just for EAA with this camera and my budget is no more than £300. I pretty much know zero about computers so would welcome any recommendations from all you experienced old hands, thanks.

Edited May 6, 2023 by Franklin

[PeterC65]

I managed live stacking (via SharpCap) with my 12mp Uranus-C camera using a 10 year old laptop initially. Bear in mind that while the image size is large you are probably taking exposures of at least 4s when live stacking DSOs so the data rate may not be that high. Also be aware that USB3 can be rather unreliable unless you have very short cable runs with not much in the way of hubs in between. I have a 5m cable run to my scope outside and that's enough to limit me to USB2. This isn't a problem though for EAA of DSOs, it's only an issue when capturing lots of frames of the Moon and Planets, and with them you can't use live stacking anyway.

The main reason for needing a powerful laptop for EAA is for plate solving. My old laptop took minutes to plate solve, the new one takes a few seconds. I plate solve almost every time I slew to a new object, partly to centre the object and partly to check that I'm looking at the object I think I'm looking at. When it was taking minutes to plate solve this was a problem.

I upgraded my laptop to a new Dell i7 based model with a solid state drive. It is much faster (orders of magnitude). It is also the main house computer so I was able to spend £1000 on it (shortly after it arrived, I dropped it on the concrete outside one night when I got tangled in the 5m USB cable - fortunately it survived).

I think the solid state drive is an advantage as it is much faster than a hard disc drive for storing the large files from a camera. A downside though is that an SSD usually has a smaller capacity than a HDD and capture files can be massive. I can easily collect 30GB of data during a single session, and I'm not doing AP.

Another thing to consider is the screen size and resolution, and support for a second monitor. My new laptop is 16", down from 17" which now seems to be the preserve of very expensive gaming laptops. It does however support a 4K external monitor and that is what I use for EAA. So I have SharpCap running on the laptop screen and the image on a second 27" 4K monitor. Getting the second monitor is one of the best EAA decisions I have made.

 

Edited May 6, 2023 by PeterC65

[Cosmic Geoff]

1 hour ago, Franklin said:

I'm going to get a better laptop which I will use just for EAA with this camera and my budget is no more than £300. I pretty much know zero about computers so would welcome any recommendations from all you experienced old hands, thanks.

If budget is limited, note that pallet-loads of refurbished business laptops are available on Ebay for far less than the cost of a new one, so you should be able to find something suitable.  I bought a Dell Vostro, about 6 years old, with  Win10, 7th gen. i5 processor, 8GB memory and  256GB SSD for a trivial sum and use it for EAA and planetary imaging. It plate-solves quickly too.

I suggest you don't buy anything below this spec, and in particular avoid older machines with hard drive, as these are power hogs.

I note in passing that you can buy a new Win 10 laptop for £100 or less (!) but the performance is what you'd expect considering that a new  laptop can cost up to £4000. So avoid the cheapies.

[Franklin]

Yes, i5 and 8GB seems to be the minimum recommended and I've just been looking at refurbished examples for around £200, the Lenovo Thinkpad 8GB looks quite rugged as well.

[Franklin]

On 06/05/2023 at 09:35, PeterC65 said:

The main reason for needing a powerful laptop for EAA is for plate solving.

I'm really taking baby steps at the moment and to be honest I'm already overwhelmed, I don't even know what plate solving is, what it's for or how you would go about it and why. I thought I could just replace the telescope eyepiece with a camera and view what it's pointed at on the laptop screen. Be good to get a working set up though because I'm very impressed with the images others are posting on here. I've been following your progress @PeterC65 in EAA and it's both fascinating and incredible, when compared to the DSO views I get visually from my light polluted garden the views you are getting with EAA are spectacular.

Currently, I'm playing around hooking up the camera and adjusting gain and exposure settings just to get a feel of what they do and this is all in the daytime. The camera is an Altair Hypercam 183C and is connected to the scope which is an SD81s via a flip-mirror, no filters, reducers or flatteners at the moment, just the camera and scope. I have the free version of Sharpcap 4.0 and AltairCapture software on the laptop. AltairCapture seems a little less intimidating than Sharpcap for me at the moment, so whilst I'm just getting used to all this stuff I've been using that.

[PeterC65]

47 minutes ago, Franklin said:

I'm really taking baby steps at the moment and to be honest I'm already overwhelmed, I don't even know what plate solving is, what it's for or how you would go about it and why. I thought I could just replace the telescope eyepiece with a camera and view what it's pointed at on the laptop screen. Be good to get a working set up though because I'm very impressed with the images others are posting on here. I've been following your progress @PeterC65 in EAA and it's both fascinating and incredible, when compared to the DSO views I get visually from my light polluted garden the views you are getting with EAA are spectacular.

Currently, I'm playing around hooking up the camera and adjusting gain and exposure settings just to get a feel of what they do and this is all in the daytime. The camera is an Altair Hypercam 183C and is connected to the scope which is an SD81s via a flip-mirror, no filters, reducers or flatteners at the moment, just the camera and scope. I have the free version of Sharpcap 4.0 and AltairCapture software on the laptop. AltairCapture seems a little less intimidating than Sharpcap for me at the moment, so whilst I'm just getting used to all this stuff I've been using that.

I followed the same path as you. No filters, Barlows or reducers initially, just the camera and the scope. I don't have a flip mirror and did struggle with finding targets initially but then I was using a camera with a much smaller sensor than yours. I think it's worth learning to point and focus the scope using the camera rather than an eyepiece. Getting the focus exactly right seems to be very important when using a camera and I now use Bahtinov masks for this.

While you're testing the kit in daylight I recommend you record the infinity focus position and then set this when you use the kit at night. That way you can be sure you will see some stars in the camera image. The gain and exposure will need to be quite different at night and you may just see a black screen initially which can be rather frustrating. At least if you know you are in focus you can point at something bright and then work out how to set the camera settings. I'd recommend bright stars rather than the Moon.

I started with an Altair camera and used AltairCapture initially. It's OK but SharpCap does so much more, particularly the Pro version which you need in order to do plate solving. This costs £12 per year but its well worth it and the support from Robin Glover is exceptional. I switched to SharpCap as I didn't want to learn about more than one software package, and I spent two whole days reading the manual, but it was worth it.

Plate solving is a software process whereby the software takes a snapshot of what you are seeing with the camera then compares it with a database of the sky to calculate the exact position to which the scope is pointing. Having got this information it can then re-sync the mount, correcting for any alignment error, or annotate the camera image to show you what objects are in the field of view, or just outside. I use it to check that I am looking at what I think I'm looking at.

I use Stellarium to control the mount when doing EAA. I get Stellarium to slew to a selected object, then I usually do a plate solve and mount re-sync. This should bring the object into the centre of the field of view. Sometimes the object is obvious, sometimes I use the image annotation to tell me what's what. This process is very useful for objects that are too faint to see in a single frame and when I can't obviously identify the stars I'm seeing from the camera against Stellarium.

SharpCap uses one of a number of third party plate solving packages which you need to download and install, but once that's done the process is seamless. You just click a button on SharpCap and its all done for you, including the mount re-sync if you want. SharpCap is very well written and documented and guides you though the plate solving tool installation process. The plate solving databases are large (several GB) and downloading these is what took the time when I installed it. It was well worth the effort though.

 

[Franklin]

15 minutes ago, PeterC65 said:

Plate solving is a software process whereby the software takes a snapshot of what you are seeing with the camera then compares it with a database of the sky to calculate the exact position to which the scope is pointing. Having got this information it can then re-sync the mount, correcting for any alignment error, or annotate the camera image to show you what objects are in the field of view, or just outside. I use it to check that I am looking at what I think I'm looking at.

I use Stellarium to control the mount when doing EAA. I get Stellarium to slew to a selected object, then I usually do a plate solve and mount re-sync. This should bring the object into the centre of the field of view. Sometimes the object is obvious, sometimes I use the image annotation to tell me what's what. This process is very useful for objects that are too faint to see in a single frame and when I can't obviously identify the stars I'm seeing from the camera against Stellarium.

Thanks Peter.

I think initially, whilst finding my feet with all this techy stuff, I will be just testing out my set up on some of the brighter "showpiece" DSO's and I've been finding and observing these objects for decades. So I'm planning on just using an EQ mount with RA tracking only, no Goto or guiding, trying to keep it as simple as possible at the start. I think I'm pretty much ready to give it a go and I'm planning on using the Vixen AP powered by USB powerbank along with the SD81s just with flip-mirror and camera. The eyepiece and camera are not parfocal in the flip-mirror so I've got a 30mm T2 extension tube to get the sensor out further, that way I can focus through the eyepiece and know that I'll be nearly there. Zooming in on a star on screen and relying on my eyes to get focus, like with the DSLR live view, though the dual speed helps a lot. I will have to get a focusing mask at some point as you suggest. The camera runs off the laptops USBconnection, so at the moment this is a very simple and portable EAA set up, I have a Celestron Lithium powertank to support the laptop battery. The only filters I have are a Neodymium and UHC-S which I can experiment with and they will have to go on the nose of the flip-mirror for starters but that may cause reflections? I read somewhere that filters are recommended to be as close to the sensor as possible. Once I get to grips with the capture side of things i.e. live-stacking for viewing and snapshots for keeping a record, I will put the camera on the SD115s which will be carried on the SXD2, this mount has the StarBook Ten Goto controller with it's own virtual planetarium and object database. It does have an ST4 port, presumably for autoguiding, so maybe this could be hooked up in some way to perform plate solving tasks once I'm more confident in using it all and am going after fainter and deeper targets.

I'm sticking with the Altair Capture software to begin with as it seems to have a much simpler user interface, which is what I need as all the functions available in Sharpcap are just way over my head at present. I'm not intending on using any calibration frames or post-processing, just want to get used to adjusting the gain and exposure and view the targets on screen with live stacking and then take a snapshot for my records.

Any recommendations on exposure and gain settings in Altair Capture for typical brighter Messier objects would be appreciated, though I think the best thing to do is to just get out there and experiment. Just panning my scope around the garden and viewing flowers on the laptop screen tells me that this set up will work well and once I get to grips with the live stacking and exposure/gain settings, I'm looking forward to punching through the heavy light pollution with my scopes.

[PeterC65]

15 minutes ago, Franklin said:

The only filters I have are a Neodymium and UHC-S which I can experiment with and they will have to go on the nose of the flip-mirror for starters but that may cause reflections? I read somewhere that filters are recommended to be as close to the sensor as possible.

I've always used filter wheels for my filters which places them close to the camera nose but not that close. I've not had any problems with reflections. I doubt the Neodymium filter will be much use for EAA but the UHC filter will be useful for nebulae just as it is when used for visual.

19 minutes ago, Franklin said:

It does have an ST4 port, presumably for autoguiding, so maybe this could be hooked up in some way to perform plate solving tasks once I'm more confident in using it all and am going after fainter and deeper targets.

Plate solving just uses the camera image and standard mount control. SharpCap can control the mount via its ASCOM drivers. ST4 isn't required. I've never used any kind of guiding.

21 minutes ago, Franklin said:

I'm sticking with the Altair Capture software to begin with as it seems to have a much simpler user interface, which is what I need as all the functions available in Sharpcap are just way over my head at present.

SharpCap does seem rather daunting at first, hence why I read the manual, but it does have a lot of useful features that are not available in AltairCapture.

23 minutes ago, Franklin said:

I'm not intending on using any calibration frames or post-processing, just want to get used to adjusting the gain and exposure and view the targets on screen with live stacking and then take a snapshot for my records.

I've only very recently started using dark frames and still don't use flat frames. You may see some amp glow with your camera which it's possible to reduce by using dark frames. My first camera suffered from amp glow but it's not a major problem for EAA even without calibrating it out.

I rarely do any post processing. I've tried capturing a stack and post stacking but usually SharpCap does a better job on the night and so I just tweak the best snapshot of the live stack from the night. The Moon and Planets need frame captures and post processing though. I've stopped using EAA for the Planets, but I can get good views of the Moon with an IR Pass filter.

29 minutes ago, Franklin said:

Any recommendations on exposure and gain settings in Altair Capture for typical brighter Messier objects would be appreciated, though I think the best thing to do is to just get out there and experiment.

The exposure and gain are very camera dependant. The gain is also software dependant (different software has different measures of gain). So it's hard to give advice. I tested lots of different gain / exposure combinations, checking each one carefully by comparing live stack snapshots side by side. I now use one setting (gain 400, exposure 4s) for all DSOs. I seem to use a relatively short exposure compared to others doing EAA but that's because I want the experience to be close to real time and to watch the live stack improving.

 

 

[PeterC65]

There is a guy in the USA, Curtis, who is posting a series of YouTube videos introducing various aspects of EAA. They are well worth watching and provide useful advice. The most recent one is about the choice of software and laptop (here).