Chasing a StarLink Satellite


Brent Boshart
 

First night out with my Mach2.  How is this for different - a StarLink satellite is a tight round dot and the stars are streaks... :)   The perpendicular movement at 00:24 is me making an adjustment with a gamepad - how fun is that?  Near the end of the video clip you can see the StarLink rotate. I'm looking forward to an ISS pass. 

https://www.youtube.com/watch?v=kDiPO-QuHPE


Christopher Erickson
 

Way cool!

-Christopher Erickson
Observatory Engineer
Summit Kinetics
Waikoloa, Hawaii


Virus-free. www.avg.com


On Mon, May 17, 2021 at 7:28 PM Brent Boshart <bboshart@...> wrote:
First night out with my Mach2.  How is this for different - a StarLink satellite is a tight round dot and the stars are streaks... :)   The perpendicular movement at 00:24 is me making an adjustment with a gamepad - how fun is that?  Near the end of the video clip you can see the StarLink rotate. I'm looking forward to an ISS pass. 

https://www.youtube.com/watch?v=kDiPO-QuHPE


Jeffc
 

> making an adjustment with a gamepad

How is the gamepad wired up?

Fwiw, I've been using APPC "remote" with a laptop.
When I need to do something at the mount (e.g. last night for some reason I had to "re-initialize / calibrate"), it is a bit awkward to "push the buttons on the control window"... sure the laptop is wifi and very portable, but it is awkward to look through the viewfinder while pushing a virtual button using the trackpad.

I do have an AP keypad, but i rarely use it as I'm mostly / always using APCC these days.

Having a simple gamepad at the mount would be useful when I occasionally need to move the scope to center an object in the viewfinder.

Btw, I have a celestron four button keypad with RJ12 connector.. I've wondered if I can plug this into the guide port, set the rate appropriately, and use it for minor moves.

-jeff


On Mon, May 17, 2021 at 10:28 PM Brent Boshart <bboshart@...> wrote:
First night out with my Mach2.  How is this for different - a StarLink satellite is a tight round dot and the stars are streaks... :)   The perpendicular movement at 00:24 is me making an adjustment with a gamepad - how fun is that?  Near the end of the video clip you can see the StarLink rotate. I'm looking forward to an ISS pass. 

https://www.youtube.com/watch?v=kDiPO-QuHPE


Brent Boshart
 
Edited

> How is the gamepad wired up?

The gamepad is not wired to the mount. It provides input to the software that calculates the satellite position.


Dean Jacobsen
 

Nice Brent!  It looks like you are making excellent progress on the project.
--
Dean Jacobsen
Astrobin Image Gallery - https://www.astrobin.com/users/deanjacobsen/


Karen Christen
 

That’s really fun.  It’s fascinating to see what folks can do with our equipment.  Thanks so much for sharing your video, Brent!

Karen

AP

 

From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Brent Boshart
Sent: Tuesday, May 18, 2021 12:28 AM
To: main@ap-gto.groups.io
Subject: [ap-gto] Chasing a StarLink Satellite

 

First night out with my Mach2.  How is this for different - a StarLink satellite is a tight round dot and the stars are streaks... :)   The perpendicular movement at 00:24 is me making an adjustment with a gamepad - how fun is that?  Near the end of the video clip you can see the StarLink rotate. I'm looking forward to an ISS pass. 

https://www.youtube.com/watch?v=kDiPO-QuHPE


--
Karen Christen
Astro-Physics


Roland Christen
 

WoW, super! Looks like the little satellite is dodging incoming missiles. Smile

Rolando


-----Original Message-----
From: Brent Boshart <bboshart@...>
To: main@ap-gto.groups.io
Sent: Tue, May 18, 2021 12:28 am
Subject: [ap-gto] Chasing a StarLink Satellite

First night out with my Mach2.  How is this for different - a StarLink satellite is a tight round dot and the stars are streaks... :)   The perpendicular movement at 00:24 is me making an adjustment with a gamepad - how fun is that?  Near the end of the video clip you can see the StarLink rotate. I'm looking forward to an ISS pass. 

https://www.youtube.com/watch?v=kDiPO-QuHPE

--
Roland Christen
Astro-Physics


Luca Marinelli
 

Hi Brent,

 

This is awesome! Was this with SkyTrack connected to the Mach2 via AP ASCOM driver or did you write a direct interface?

 

Really nice work!

 

Luca

 

From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Brent Boshart via groups.io
Sent: Tuesday, May 18, 2021 7:20 AM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Chasing a StarLink Satellite

 

[Edited Message Follows]

> How is the gamepad wired up?

The gamepad is not wired to the mount. It provides input to the software that calculates the satellite position.


Brent Boshart
 

> This is awesome! Was this with SkyTrack connected to the Mach2 via AP ASCOM driver or did you write a direct interface?

That is with a direct interface.  Unfortunately currently both the AP ASCOM driver and APCC have a limitation that makes this accurate of tracking not possible.  I use a loop that calculates difference between the satellite current position and the mount's position to make small adjustments to the satellite's rate of movement in order to keep it centered. Both the ASCOM driver and APCC poll the mount about once every second for its position instead of sending "real time" data when its requested - fine for most applications.  So if I am slewing at 3 deg/sec the position I get from ASCOM/APCC could be a full second old and off by 3 degrees.  My FOV in this video is only 1 degree.  You can see in the video it does not stay exactly centered, that is pointing error because I only did a one star sync for alignment. It would be nice to be able to use the APCC modelling.  According to the position data I receive comparing to the calculated satellite position, I am able to keep the satellite within 0.5 arcminutes of center, the rest is calibration/pointing error.


Ray Gralak
 

Hi Brent,

Actually, you can turn off the caching of RA/Dec in APCC, but the option is not available in the user interface. APCC comes with an application called Horizons, which can track moving celestial objects and artificial satellites. Horizons turns off APCC caching when it is connected to the mount.

-Ray

-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Brent Boshart
Sent: Tuesday, May 18, 2021 9:08 AM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Chasing a StarLink Satellite

This is awesome! Was this with SkyTrack connected to the Mach2 via AP ASCOM driver or did you write a direct
interface?

That is with a direct interface. Unfortunately currently both the AP ASCOM driver and APCC have a limitation that
makes this accurate of tracking not possible. I use a loop that calculates difference between the satellite current
position and the mount's position to make small adjustments to the satellite's rate of movement in order to keep it
centered. Both the ASCOM driver and APCC poll the mount about once every second for its position instead of
sending "real time" data when its requested - fine for most applications. So if I am slewing at 3 deg/sec the
position I get from ASCOM/APCC could be a full second old and off by 3 degrees. My FOV in this video is only 1
degree. You can see in the video it does not stay exactly centered, that is pointing error because I only did a one
star sync for alignment. It would be nice to be able to use the APCC modelling. According to the position data I
receive comparing to the calculated satellite position, I am able to keep the satellite within 0.5 arcminutes of center,
the rest is calibration/pointing error.