Slewing to a target


#1

This might be a really stupid question, but I haven’t found how to actually select a target and slew to it using SGP.
There are forums and videos showing how to plate solve, set up mosaics etc etc, but no where to show how, of even if it is possible to actually enter a target, and slew to it initially.
Can this be done? Or do I still need to use Catres Du Ciel?
Thanks.


#2

I recorded some videos that show how to set it SGP and a sequence, in this case using Astroplanner. Hope these help:

http://www.digitalastrophotography.co.uk/Astrophotography/Videos.html

Alternatively you can type in target coordinates or more usefully, pull in any image, plate solve it and click the option that uses the platesolve center as the sequence target.


#3

There’s several different ways to get to a target. Open the target settings dialogue (gear icon next to target in the Sequencer window).

From there you can enter coordinates and “slew to” the target. This does not use plate solving and will only get you close to your target. The option to “center now” uses plate solving and will get the target coordinates dead center. Another option is to find an example image of the target you are looking for on astrobin or flickr, copy the url and paste it into the reference data spot. This will import the coordinates with the image (if that info is available with the image) into your target location. Then you can center now (using plate solve) or slew now.

Finally, the best option is to use the Framing and Mosaic Wizard add-on to plan your imaging target.

If all you want to do is push a button and slew your mount to the general vicinity of an intended target then yes, use cartes du ciel or another planetarium program. But that doesn’t get you dead center on your target like plate solving will. Remember that SGP is an image capture program, not a planetarium. SGP’s tools are intended to automatically get you dead center on your target, but not to work like a planetarium or like your mount hand control.


#4

Hi Buzz, and pardon me Willgriff21 for slipping in here.

Buzz,
I want to compliment you on your well done and informative videos. Bravo! Seeing the steps go a long way in clearing up confusion.

There is a question/comment on your “Powering On” video. I understand your setup is mobile so you must calibrate PHD2 before your image session. What I noted was that you manually force a guide star selection at the start of the process. While my understanding from comments from this or the PHD forum was that PHD would select a star on its own as long as it was looping, my experience was most times this was not true. I’m curious what caused you to take your approach.

Thanks,

Mark


#5

Hi Mark - I was calibrating PHD2 each night to be on the safe side as I could never be sure the alignment of the camera would be identical to the prior session (my field flattener rotation fixing tends to slip)

I often start a sequence at dusk to start imaging later on when the subject rises over 40 degrees and I guess, like some others, I found it comforting to achieve approximate focus and know the guider was working before walking away. In the early days I would also manually slew and center and wait for the subject to reach sufficient altitude.

SGP is a different beast and from the start it has proved to be an order of magnitude more reliable. Now that Beta 3 has the PHD autostart working for all eventualities, my next session will trust SGP to start PHD2 cycling, select the guide star, calibrate and start the sequence for me. In the latest versions of SGP, PHD2 just needs to be connected to camera / mount, it does not need to be looping for SGP to run with it.

The only thing you may have to watch out for is the star selection choosing a double star, which may confuse things.

I should really do another video with everything automated. That would show the full intelligence of the system.

Hope that helps.
Chris


#6

Hi Chris

Let me also congratulate you on your excellent videos. Are these widely publicised? If not, they should be! IMHO they ought to be included as a link in the User Contributions section on the SGPro Support page. You might want to consider a YouTube channel for ease of access.

Regards
John


#7

Current versions of PHD2 make a concerted effort to avoid selecting double stars. If you ever do see this happen, please save the image (File => Save Image) and your phd2 debug log and post a message on the phd2 forum so we can investigate.

Thanks,
Andy


#8

No problem Andy, I have not witnessed it myself, I was being cautious and just imagined it would be tricky to guide with when there was seeing too.

I spoke to soon - I unexpectedly have a clear night and tried doing another video showing PHD auto-starting.
I had problems with a timed sequence startup which appear to relate to PHD communications. I have put the details in a separate thread with log files in dropbox etc. As PHD never got to start cycling / calibrating, it did not produce a log file.


#9

Thanks very much for these informative instruction videos. It really cleared up a few confusing issues for me.


#10

Thank you all for your comments. Some very useful information and videos
Apologies for not replying, I’ve been away. I look forward to trying to get my head around if when I get back :slight_smile:


www.mainsequencesoftware.com