PushTo direction

[Cyg]

Hello,

In the case of no-goto/manually driven mounts, like Dobson and smaller mounts, it would be very helpful to have a software push-to helper :
- from a capture, doing a platesolving
- from the platesolved stars and having set a target (coordinates/object name ?), display a vector in the direction to the target and a size of the distance relatively to the field of view to have an idea if the strenght to apply to the next move.

It could be close to the polar alignment tool but having any other targets/coordinates.

I suppose it would be easier in Alt / AZ coordinates than RA/Dec, even if on my personal case I am using an equatorial table.

I hope it will interest other users with manual setups,

Best regards,
Cyg aka Fabrice

[admin]

Hi,

thanks, yes, I think there was another similar suggestion recently of 'push to guidance', which I am intending to implement in the future.

cheers,

Robin

[PeterO]

Hi Fabrice,
I use stick-on accelerometers to determine declination and hour angles in order to push a telescope from pointing at visible reference stars to invisible target stars. Sometimes I use SharpCap blind plate solving to provide a reference when stars are not readily available as references. The blind plate-solving result is displayed by SharpCap so it can be entered manually into my app, which shows the real-time progression pushing towards the target. Positioning accuracies are within two arc minutes.

Blind plate solving is quite slow because it analyses the whole sky. However, PushTo systems can be set up to point telescopes to within a fraction of a square degree using a number of cheap and simple methods such as my gravity-referenced accelerometer method. I asked Robin whether there was a way to enter the approximate direction of the reference star into SharpCap to overcome the slowness of the blind plate solving. He provided some potential solutions, which I've copied below with his permission:

Copy of Robin's response below:

On the subject of 'PushTo', I have some ideas in that direction, but haven't had time to implement them yet.
The idea was to have a way to enter the target co-ordinates and then for SharpCap to repeatedly plate solve - possibly using 'blind' solving initially, but then using 'fast' local solving to update the co-ordinates frequently. That could then give you guidance on the remaining adjustment needed - something like "+0h14m RA, -0 30m Dec'

Another thing you can do right now to speed up plate solving is to use the 'Telescope Simulator .NET' mount that is built into ASCOM. From SharpCap's point of view, it looks like a real telescope mount, but it doesn't actually have any hardware. The trick is that you use the control panel (or the GOTO tool) in SharpCap to 'move' that mount to the vicinity of the co-ordinates of the real telescope in SharpCap. Then, when you do 'blind plate solving', it will start its search from the mount co-ordinates and should be a *lot* quicker.

In theory, a similar approach would be a way to integrate your ideas about pointer readouts - Someone with some programming skills could make a separate ASCOM driver a bit like the simulator one that comes with ASCOM that lets you type in the current readout co-ordinates, and SharpCap would consider that to be data coming from a GOTO mount.

[Tiago Ferreira]

I've been using the ascom with stellarium and couldn't live without it.
To do it only through sharpcap would be amazing

[anaximandros]

+1

[admin]

Hi folks,

I have been experimenting with this feature, and currently have a prototype that looks like this

Capture.JPG (112.91 KiB) Viewed 16475 times

Right now, I can only test with ASCOM sky simulator (I only got things working today and currently 100% cloud cover). It works, but isn't polished yet.

Since I'm not really someone who uses a push-to system, I'd be very interested in feedback on what information is shown and whether it is useful and presented in the right way...

I've included the required movement in RA and Dec, on a coloured background that shades from red (more than 5 degrees) through orange and yellow to green for small offsets (less than 0.01 degrees).

The total distance from the target is similarly shaded, that's a great circle distance from the current point to the target point in degrees of arc.

I have also included the movement required in horizontal co-ordinates (left/right/up/down), which may be more useful for those using a Dobsonian. The left and right here are in compass degrees, so when you are pointing to a target high in the sky (as in the screenshot) the compass movement in degrees may be larger than the actual distance to the target via the great circle calculation. It seems a bit weird, but I think it's the right choice - probably...

Any comments on this from people who are using PushTo on a regular basis are very welcome,

Robin

[Cyg]

Thank you very much Robin, that's very kind of you to have implemented this so quickly !

Indeed RA/Dec and horizontal/vertical moves are both interesting since the Dobson could be directly on the floor or sitting in an equatorial platform.
I personnally added some graduations in both axes of the Dobson, so the relative distance mentioned here should be easy to achieve manually in 1 try only, and not dependent from the camera sensor size or its rotation in the focuser.

I was looking at it on the interface from the latest delivery but could not find it, Tiago reported me that you are planning to add it to the next beta release, so it's great !

Best regards,
Fabrice

[admin]

Hi Fabrice,

thanks for the feedback - sounds promising.

I had intended to included it in the last release on Monday, but I forgot to remove the 'internal testing only' check from the code, so it does not appear in the menu of that version. Watch out for next Monday's update though

cheers,

Robin

[admin]

Hi,

just to let you know that this feature is now available to test in SharpCap 4.1.10652.

cheers,

Robin

[Cyg]

Dear Robin,

Thank you a lot for the delivery !
I tried it on the real sky, the feature is really what we need but I encountered some difficulties with the platesolving itself with very few success, as for the plate solve standalone feature.
I checked with SharpCap 4.0 and the plate solve was 100% successful with 100 of stars recognized but 0 or just a few on the v4.1, at the same time with the same conditions ?

Also one thing that could be annoying is the last successful result that is quickly replaced by another message mentionning that another acquistion is under progress.

Best regards,
Fabrice