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First Light : Edge HD 8 and Raspberry Pi 4 with Stellarmate OS - The Struggles and the learnings

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#1 tsk1979

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Posted 23 May 2020 - 08:07 PM

Buy refractor.

Buy a refractor...

 

This reply exists in every thread on any forum I have asked about the SCT imaging.

 

But I went anyways to the Edge HD8. With 600mm F/8 imaging under my belt, I decided that the next stop has to be 2000mm at F/10

And to punish myself further I also decided to whip up the Raspberry pi 4 solution and install Stellarmate OS

 

But before you get bored and stop reading this tale struggle and more, I have not decided to quit Astrophotography. I am going to try again in a couple of days (6pm-6am means I need to have a quite night in between)

And, one more thing. Before my tale, tell me what the hell does this picture mean?

If my collimation is out I should have a crooked donut. This one seems to be missing a piece. Bad seeing maybe?

Capture.JPG

 

The picture was taken not dead on (I wonder why I did that and took it from the side). I guess I was more concerned about who ate the donut

 

Okay lets get on with it. First and foremost my setup

setup.jpg

 

I installed stellarmate OS on a R-PI4, and control it through VNC. On paper, it means a killer astrophotography system. But its literally so, esp with stuff like SONY DSLRs etc.,


Edited by tsk1979, 23 May 2020 - 08:08 PM.


#2 tsk1979

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Posted 23 May 2020 - 08:25 PM

The night started young. Starting a little after six, I was at the site around 8pm. All the fishermen and picnickers were leaving and by ten it was just me and another imager socially distancing, happily collecting photons on a big refractor (The one you keep asking me to buy).

 

Though I had practiced at home, its another matter to actually setup at side and polar align. For a first time polar alignment with iPolar, I first found it very very frustrating. I spend over 20 minutes, and the **** crosshair kept moving away from the circle.

And then I realized what I was doing. I was setting one axis, lets say altitude, and then tightning it.

I figured out the trick. First loosen both altitude and azimuth. Get your cross-hair centered and then tighten stuff up. I guess next time it will be easier. 

 

I am glad I did this way. And guess what the only thing with which I did not struggle at all with was "Guiding". I was able to successfully guide for the first time ever

It started like this, and then magically within half a minute settled down to the second. Picture. I don't really know what all that means for EKOS internal guider, but I guess no up down means good?

 

Capture.JPG

 

Capture2.JPG

 

But I am getting ahead of myself. The biggest problem is "Where am I". And normally for 600mm, its very easy to figure out. But I had a trick up my sleeve. Plate solving. Yay.

 

Struggle number one. To plate solve you should be able to see stars. Our of focus telescopes, do not see any stars. And to focus reliably you have to point to a bright star. But how do you point to a bright star if you can't find it. You get the drift right. And guess what, my scope was on the other end of the focus limit. After lots of turns and doing a binary search algorithm with my fingers, I was finally able to focus reasonably.

 

And then came the next shocker. The **** thing would not plate solve. It would keeps saying error, error error... I tried fixing all things I did not need to fix (exposure, focus) and wasted an hour I guess on this.

And then I realized what was happening.

 

You know I the mount was asking me something else, but I was saying something else. I was worried about the where, but the question was when?

 

You see, Raspberry Pi running stellarmate OS needs something called DS3231, which is a real time clock. Otherwise it will lie to the mount on the when, and turn itself into a time machine. 

 

So every time I reconnected, I had to painfully set the time, and finally plate solve was happening. It was also 3am, and morning was approaching. And then I started imaging, and the application started randomly crashing. Something sony no like Stellarmate kind of stuff. I finally found a trick. "NATIVE" mode for images, and don't do too many previews and focus aid things

 

But i guess an entire night of setup taught me a few valuable things

 

  • SCTs are hard for beginners and intermediate imagers, but you should get one
  • Raspberry Pi systems are painful. But they are amazing too once you figure it out. Eg https://www.amazon.c...t/dp/B01M105UFC will make a lot of my problems go away. Get a R-Pi 4 + Stellarmate OS instead of going with solutions people love because you will get locked to a vendor
  • GEM45 is a very spectacular mount. But does make a TaK Tak Tak Tak periodic sound, which I need to ask iOptron about. And when the guiding is struggling to get it in line, you can literally hear the whirring. 
  • Don't give up, even if you have a Newtonian. 

 



#3 Hobby Astronomer

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Posted 23 May 2020 - 10:33 PM

Looks like you are having fun. Looks like you have a good start.

 

You have a nice scope and mount.

 

You need an OAG.

 

You might need a guide camera with LARGE PIXELS.

 

You might need to align the guidescope with the tube if you continue to use this.

 

Optional:

 

Tube rings

 

longer dovetail.

 

Keep the peep scope guider on and the cameral with sharp cap you can polar align.

 

Get the focal reducer since you can drizzle your images from F/7 to a larger size than F/10 and be within the limits of seeing.

 

Do you have an electronic focuser?

 

Have you automated this with Sequence Generator Pro?

 

Buy a laptop...Set up plate solving software.

 

.......

 

.......

 

........

 

I use the same scope you do. Love it.

 

HA



#4 tsk1979

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Posted 23 May 2020 - 10:42 PM

Thanks!

 

But I found out just now that my brand new OTA has a small deformation on the inside of the tube, hence my weird collimation star. Its still within the 30 day return. I have contacted highpoint scientific 



#5 Hobby Astronomer

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Posted 23 May 2020 - 10:51 PM

The 8 Edge is a great sized scope and use the F/7 reducer to choke it down. I have the 11 and the 8. Field of view is wider on the 8 and if you drizzle you can get more out of it most of the time than the 11.



#6 TelescopeGreg

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Posted 23 May 2020 - 10:53 PM

I am glad I did this way. And guess what the only thing with which I did not struggle at all with was "Guiding". I was able to successfully guide for the first time ever

It started like this, and then magically within half a minute settled down to the second. Picture. I don't really know what all that means for EKOS internal guider, but I guess no up down means good?

"No up and down" is good, but look carefully.  It looks better because the vertical scale changed!  Not that it was horrible before, but it's not perfect either.  At that focal length, you probably need to do a bit better in order to get really good images, but that it's working at all is a clear accomplishment.  So, for a first night out, I'd call that the success.  Work on the guideing parameters (run the Guiding Assistant), and check the overall scope balance.

 

To the "where am I pointed" problem, I ditched my "finder" scope, since with its magnification sitting on top of such a blunt object, "finding" anything was near impossible (as you have seen).  I got a "Telrad" finder, and it saved a significant crop of hair that would have otherwise littered the ground.  That said, plate solving is a much better solution, and your Pi is quite capable of doing it.  I use ASTAP on mine.  Just takes seconds.  A note, my camera doesn't support remote USB control, so I use my guider for plate solving, after first very carefully aligning it to the main scope.  The only issue with this is that I have to disconnect the plate solver once the scope is aimed, in order for the guide software to connect to the same camera.

 

I'm using a Raspberry Pi 4B with Astroberry on it, but your problem with Time is common to any computer that doesn't have a battery-backed clock.  You can set the time manually, as you did, or you can let the Pi connect to the Internet via its WiFi interface.  This can be your cell phone in Hotspot mode.  Alternatively, I vaguely recall that there is a way to have the Pi get its time and location from the mount, which may have the battery-backed RTC.  Or just get the time module; they're really cheap.  I have one on my "saved for later" list, just waiting for another order to throw it in with (for free shipping).

 

You're doing great!  Keep it up!



#7 khobar

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Posted 23 May 2020 - 10:53 PM

Do yourself a favor and add a GPS module, either a GPIO or USB (I use the GPIO option to keep a USB port open). 

 

And have you used the Ekos polar alignment routine?



#8 tsk1979

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Posted 23 May 2020 - 11:36 PM

"No up and down" is good, but look carefully.  It looks better because the vertical scale changed!  Not that it was horrible before, but it's not perfect either.  At that focal length, you probably need to do a bit better in order to get really good images, but that it's working at all is a clear accomplishment.  So, for a first night out, I'd call that the success.  Work on the guideing parameters (run the Guiding Assistant), and check the overall scope balance.

 

To the "where am I pointed" problem, I ditched my "finder" scope, since with its magnification sitting on top of such a blunt object, "finding" anything was near impossible (as you have seen).  I got a "Telrad" finder, and it saved a significant crop of hair that would have otherwise littered the ground.  That said, plate solving is a much better solution, and your Pi is quite capable of doing it.  I use ASTAP on mine.  Just takes seconds.  A note, my camera doesn't support remote USB control, so I use my guider for plate solving, after first very carefully aligning it to the main scope.  The only issue with this is that I have to disconnect the plate solver once the scope is aimed, in order for the guide software to connect to the same camera.

 

I'm using a Raspberry Pi 4B with Astroberry on it, but your problem with Time is common to any computer that doesn't have a battery-backed clock.  You can set the time manually, as you did, or you can let the Pi connect to the Internet via its WiFi interface.  This can be your cell phone in Hotspot mode.  Alternatively, I vaguely recall that there is a way to have the Pi get its time and location from the mount, which may have the battery-backed RTC.  Or just get the time module; they're really cheap.  I have one on my "saved for later" list, just waiting for another order to throw it in with (for free shipping).

 

You're doing great!  Keep it up!

 

Yes, I plan to get the time module which connects to GPIO. But if hotspot mode works, that is good too. But sometimes places I am at have no cell phone network, so I guess GPIO is the perfect accessory. Its about 7$ I think!

Do yourself a favor and add a GPS module, either a GPIO or USB (I use the GPIO option to keep a USB port open). 

 

And have you used the Ekos polar alignment routine?

My mount has GPS attacked. The problem was with time. I guess a GPIO RTC module will work.

 

For polar alignment I use the ioptron software on the laptop (iOptron iPolar camera)

Polar alignment was very good with + and O mating perfectly

 

 

But I guess I have to return the OTA to highpointscientifc.com and get a replacement.


Edited by tsk1979, 23 May 2020 - 11:36 PM.



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