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Myriad of questions, any all help wanted. (Mini PC, 1600MM Pro, SharpCap)

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#1 CrossAerialPhotography

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Posted 23 January 2019 - 11:11 PM

Alright, so I am hoping that I am able to keep this on topic but I have questions ranging from camera settings to equipment so here we go...

 

I will start out with equipment. Right now, my batteries suck. I know I need to go to something like a 100ah battery and all that, BUT I had an idea. Right now, the issue with power comes from my laptop. It's eating 65w of power and makes up 80% of my power consumption. So I figured, instead of getting a massive heavy battery, what if I minimized the laptop with a mini PC. I know this question gets asked a bunch and I've read alot of the post. What I dont understand is the setup stuff. Like when you are in the field, you hook everything up to the PC, power it on and all that. But from there, I hear about 20 different ways to connect to the device. All I care about is being able to PA in SharpCap, and setting up APT. What is the easiest way to do that? 

 

 

Next, I have just purchased a 1600mm Pro. Firstly, I FREAKING LOVE IT. Man it's so much "easier" than a DSLR in some manners, but I dont understand some things. The biggest thing is gain and offsets. I pretty much have everything at default or zero, but I was wondering what is correct? Im keeping my binning at 1x1 but I dont know with gain what to do and neither with offset. On that same vein, how do yall handle cooling in the cold? I am worried about going below 32*F due to condensation forming and all that, ice on a camera scares me! So is there any rules to cooling or do you pretty much just let it cool to as cold as possible relative to ambient? I know John Rista has show benefits to going really cold. 

 

 

And now, polar alignment. Right now, I am using a 3D printed setup of rings to hold a SMC 200mm F4 lens to a ASI120MM. It is pretty solid (5min subs on my AVX with my setup) but I want something better. The whole setup, plastic or metal, just seems janky to me. I feel like if you mounted a guide scope in the same manner as you do the main scope, it would be much more solid. The only thing I worry about is alignment. Right now, my guidescope isnt really aligned to the same point as the imaging train, how much of an issue is that? But before commenting on that, I need to speak about SharpCap.

 

In sharpcap, I have issues alot with either the alignment star jumping around or not being able to pickup stars despite them being clearly visible in the image. The first issue is really annoying. I can be aligning have my error approaching zero and be off by only a few seconds, then suddenly, it switches to a new star and says poor and be off my several minutes. I am assuming this due to user/equipment error. The only point of error I can think of is the lens. Maybe it's not letting in enough light and so sharpcap freaks out when losing a star due to seeing or something like that and changes the error. I dont know this tho.

 

 

 

Any and all help is appreciated! Thanks! 



#2 ks__observer

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Posted 23 January 2019 - 11:35 PM

Re gain setting:

As everyone on here knows, unity gain is magic (joke...).

Actually for starting out unity gain is probably best combo read noise and dynamic range.

For exposure range:

https://www.cloudyni...d-maybe-qhy163/

 

For PA you usually don't have to stress about being crazy accurate:

http://celestialwond...xErrorCalc.html

 

Sharpcap is great.

 

Re temp:

Summer i usually set it to 0C and winter -10C.


Edited by ks__observer, 23 January 2019 - 11:38 PM.


#3 CrossAerialPhotography

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Posted 23 January 2019 - 11:48 PM

Re gain setting:

As everyone on here knows, unity gain is magic (joke...).

Actually for starting out unity gain is probably best combo read noise and dynamic range.

For exposure range:

https://www.cloudyni...d-maybe-qhy163/

 

For PA you usually don't have to stress about being crazy accurate:

http://celestialwond...xErrorCalc.html

 

Sharpcap is great.

 

Re temp:

Summer i usually set it to 0C and winter -10C.

Ive read that first link before but I really dont get it. Im in a Orange/Yellow Zone and my scope is F/5.4 which would put me at around 2.5 min subs at a gain of zero. That just seems insanely low. I see so many more images at 5-7min. If this was the most 'efficient' way to image, why dont more people do it? 

 

As for the second, I dont know some of the data I would need to enter. 



#4 james7ca

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Posted 24 January 2019 - 01:01 AM

If you want to use some kind of wireless remote access on a mini PC I'd suggest reading this post:

 

  https://www.cloudyni...-3#entry7754612

 

In this case, you only need your laptop turned on while you are making changes to the setup on the mini PC, so one battery charge on the laptop should last several nights. It also means you don't need a display for the mini PC which will save a lot of battery power while in the field.



#5 ks__observer

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Posted 24 January 2019 - 01:27 AM

Ive read that first link before but I really dont get it. Im in a Orange/Yellow Zone and my scope is F/5.4 which would put me at around 2.5 min subs at a gain of zero. That just seems insanely low. I see so many more images at 5-7min. If this was the most 'efficient' way to image, why dont more people do it? 

 

As for the second, I dont know some of the data I would need to enter. 

Re exposure tables:

I think many experienced imagers use the tables as starting point and guide.

The lower the read noise the shorter the exposure time necessary to reach 95% best snr for sub.

The brighter the sky background the faster you will hit the 95% mark -- but 95% SNR from LP site will be less SNR than the SNR at a dark site (same idea for NB).


Edited by ks__observer, 24 January 2019 - 08:04 AM.


#6 CrossAerialPhotography

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Posted 24 January 2019 - 12:36 PM

If you want to use some kind of wireless remote access on a mini PC I'd suggest reading this post:

 

  https://www.cloudyni...-3#entry7754612

 

In this case, you only need your laptop turned on while you are making changes to the setup on the mini PC, so one battery charge on the laptop should last several nights. It also means you don't need a display for the mini PC which will save a lot of battery power while in the field.

So if not an existing network (IE, out in the field), you cant use teamviewer or the other programs because you are not on a network correct? I would probably just use a Ethernet cable instead of something wireless. 

 

Re exposure tables:

I think many experienced imagers use the tables as starting point and guide.

The lower the read noise the shorter the exposure time necessary to reach 95% best snr for sub.

The brighter the sky background the faster you will hit the 95% mark -- but 95% SNR from LP site will be less SNR than the SNR at a dark site (same idea for NB).

I think I would start where it recommends, but add a little bit of time to cut down on the number of subs because 20-30 light frames isnt so bad but 50 would be quite large. 



#7 Kevin Ross

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Posted 24 January 2019 - 01:22 PM

I *think* TeamViewer needs Internet access, even when you're connecting to a computer right next to you.

 

Use VNC or Remote Desktop, which will make a direct connection from your laptop to the scope computer. You need a network connection between the two, but no Internet is required.

 

Set the mini PC up so that it creates its own WiFi network (a hotspot), then from your laptop or tablet, you just connect to its WiFi.



#8 2ghouls

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Posted 24 January 2019 - 01:26 PM

My suggestions: 

 

  • Just get the big marine battery and a cheap rolling tool chest for it for transport. The cost of those two items will be lower than a good enough mini PC (with all accessories) and MUCH less hassle since you already have a laptop. I gave up on the mini PC concept because of unreliability, wireless dropouts, lag, slow solves, etc. etc.
  • I like gain 200, offset 50 for narrowband and gain 75 offset 15 for LRGB. But yes look at the tables linked as they probably know better. 
  • Definitely cool your camera! I've never had a frost problem. I am in the NE USA and use -15C all year round. Makes Dark libraries super easy.
  • Polar alignment: the closer you can get your guide star centered in the guide camera/ imaging camera the better. I've had issues when they are not close, but YMMV. I don't use SharpCap PA so I will let other answer that.


#9 Michael Harris

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Posted 24 January 2019 - 02:06 PM

Not sure if this helps but my guide scope (a little Orion 50mm guider) is mounted on an upside down Vixen style dovetail bar on top of my scope rings. The guide scope rings and bases are from ADM and are rock solid. I have never bothered to align the guide scope with the main scope, all you need is a visible guide star not less than 10 pixels or so from the edge of the guide chip. You can see what I have here. I bought the ADM set through high point scientific to replace the stalk-style mount that came with the guide scope.

 

imaging setup


#10 CrossAerialPhotography

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Posted 24 January 2019 - 06:23 PM

 

My suggestions: 

 

  • Just get the big marine battery and a cheap rolling tool chest for it for transport. The cost of those two items will be lower than a good enough mini PC (with all accessories) and MUCH less hassle since you already have a laptop. I gave up on the mini PC concept because of unreliability, wireless dropouts, lag, slow solves, etc. etc.
  • I like gain 200, offset 50 for narrowband and gain 75 offset 15 for LRGB. But yes look at the tables linked as they probably know better. 
  • Definitely cool your camera! I've never had a frost problem. I am in the NE USA and use -15C all year round. Makes Dark libraries super easy.
  • Polar alignment: the closer you can get your guide star centered in the guide camera/ imaging camera the better. I've had issues when they are not close, but YMMV. I don't use SharpCap PA so I will let other answer that.

 

-Yeah I just really dont want to lug that thing up and down 3 flights of stairs. 

-Perfect! Ill try those!

-I do cool it, I just wasnt sure if there was a 'too cold'

 

Not sure if this helps but my guide scope (a little Orion 50mm guider) is mounted on an upside down Vixen style dovetail bar on top of my scope rings. The guide scope rings and bases are from ADM and are rock solid. I have never bothered to align the guide scope with the main scope, all you need is a visible guide star not less than 10 pixels or so from the edge of the guide chip. You can see what I have here. I bought the ADM set through high point scientific to replace the stalk-style mount that came with the guide scope.

 

I like that! Seems solid. Do you have any issues with sharpcap? 



#11 Michael Harris

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Posted 24 January 2019 - 06:57 PM

-Yeah I just really dont want to lug that thing up and down 3 flights of stairs. 

-Perfect! Ill try those!

-I do cool it, I just wasnt sure if there was a 'too cold'

 

I like that! Seems solid. Do you have any issues with sharpcap? 

I haven’t used SharpCap but I have never seen a bad review on this forum for it. I use the PoleMaster and like it, but that and SharpCap don’t have Mac versions so I minimize my Windows laptop use. Plate solving for polar alignment definitely sounds good though.



#12 james7ca

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Posted 24 January 2019 - 10:28 PM

As for using remote access software over WiFi, there is a lot of confusing or misleading or just plain incorrect information shared on the internet about this topic.

 

First, Windows 10 no longer offers any built-in or easy to use process to create an ad hoc or point-to-point wireless network between two computers. So, the only way you can wirelessly connect two computers (without the internet) is to:

 

A.) Create a local WiFi network using a WiFi router or access point (add another piece of hardware).

 

B.) Use a third-party solution like Connectify.

 

C.) Or,  attempt a poorly documented and complex process in order to try and "force" Windows 10 to create an ad hoc or point-to-point network (the latter used to be fairly straightforward under earlier version of Windows, but AFAIK that is no longer true under Windows 10).

 

However, there is a choice that I'll call little "d" that I documented in my previous link (using Microsoft's Wireless Display feature), but YMMV in terms of reliability and performance and I probably wouldn't recommend the Wireless Display solution unless you are unhappy with options A, B, or C.

 

Second, a WiFi hotspot is NOT really the same thing as an ad hoc or point-to-point wireless network connection. A hotspot simply allows you to share an existing internet connection. However, if you want to use remote access software over WiFi you'll either need a connection to the internet or attempt options A, B, C as outlined above (or the substitute little "d").

 

Third, TeamView will work without an internet connection, but without the internet you'll still need some form of network to allow the remote client to communicate with the host (the PC you're wanting to control). So, for wireless access back to options A, B, or C.

 

All that said, Windows 10 itself, being the complex and somewhat archaic software that it is, MAY offer some other options that I'm not aware of to support ad hoc or point-to-point wireless networking. Thus, if anyone knows of a relatively simple and built-in method I'd sure like to know how that is done. Note, I already know about some of the third-party solutions (Connectify, et. al.) and there are a few procedures on the internet which claim to show how to setup ad hoc networking under Windows 10, but YMMV. Here is one link which makes such claims (with the setup procedure for Windows 10, note this appears to be a much easier process than what was given on Microsoft's own support pages, so maybe things have changed in the last year or two):

 

  https://www.lifewire...-network-818272

 

All in all, if you want wireless networking you may just want to use a separate WiFi access point (option A, above, even when mobile and in the field). In fact, if you want 5GHz networking (to avoid problems with USB3 interference) then this may be your only good option.


Edited by james7ca, 24 January 2019 - 11:13 PM.


#13 CCDer

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Posted 25 January 2019 - 01:09 AM

As for mini PC's, I've had a host of problems with the newer low power ones when temps approach zero Celsius. If you're planning to use equipment at those temps you'll need to take special care selecting a PC that does low temps. Alternately, you could put it inside a box but you should monitor it in advance at low temp to see how heat gets controlled/retained. New software is out there that runs on Raspberry PI's and PI's are good to at least zero Fahrenheit. And VNC works on both.




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