Automated calibration run will not plate solve

[Paul Haese]

OK maybe I am going something wrong. I am used to just hitting the run button on AAG Tpoint Mapper so something seems a miss in SkyX

Now to explain. I have the camera at 0 degrees orientation and it is directed connected in the SkyX. I have the dome directly connected in the SkyX too.

I setup the parameters for 6-8 points in tpoint add on. I centred a bright star (Canopus) and map that first point and then press the run button in acquire pointing samples. It takes the frame, downloads but cannot plate solve. I think I have the plate scale right or close to it. What else could be wrong?

[Logieberra]

Paul, have you synchronized the mount? After homing, I usually Sync just there. Take a photo. Click the centre of photo. Linked photo writing should display on photo. In Telescope tab, select Synchronize on Linked Photo. Go into automated Tpoint mapping after that.

That's my best guess...

[frolinmod]

For some reason a lot of people stumble over image link at first. I did too, yet today I have no idea why that was. It just plain works great, so why did I ever have any problems with it? I dunno!

If you use the regular image link you can be way off on the scale or not even know it. Works great so long as you're within a few fields of view. The All-Sky image link requires you to know the exact plate scale for best results. Yes, it has a mode in which it will accept a range, but if you really want it to work reliably you'd better know the exact scale. It's not as flexible in that regard as the regular image link. I don't mind that trade off considering that it doesn't need to know the RA/DEC at all or even be anywhere close.

Also note that Tools->Image Link vs. Automated Calibration image link use two different default sets of parameters. The first is default.sxt and the second is AutoPointingRun.sxt.

Due to catalog capriciousness, please don't expect to get a successful image link pointed directly at a super bright star like Canopus. There aren't usually a lot of stars in the catalogs adjacent to super bright stars. Please point at least a little off from the star.

If you don't already have UCAC4, please get it. UCAC3 will do in a pinch, but UCAC4 is really good. NOMAD is usually a waste of time.

[Paul Haese]

Thanks guys. Not synchronised the mount. I will look that up. The Sky6 with AAG Tpoint Mapper I never had to synchronise the mount. I will let you know how it goes.

[frolinmod]

Here's a good post concerning when it's a good time to do what by John Brooks over on the SB forums:

http://www.bisque.com/sc/forums/p/20352/88960.aspx#88960

[gregbradley]

Man this is not a user friendly feature. It works eventually. I have often had trouble with it.

Firstly it won't plate solve unless the image is saved. So that save images box has to be checked.

Secondly when working out the image scale that is for 1x1 binning. If you are using 2x2 or 3x3 then you multiply your image scale. So the image scale entered is for the binning you have set your camera to.

Lastly you need to have the north position angle pretty close. I use CCDsoft. So I do a plate solve in CCDsoft first and then take the north angle off the result and enter it.

Camera has to be connected in the camera tab I am pretty sure.

Otherwise its a matter of having enough stars in the field (not usually a problem).

When it works it feels simple but getting there is too hard. It needs to be simplified in my opinion.

Greg.

[cfranks]

Paul,

Try TSX Menu Telescope/TPoint Add On/Calibration Run/Automated Calibration and at the bottom Take and Image Link Photo. I have never had this fail and it returns with the Image Scale and Position Angle.

Charles

[frolinmod]

Nope. Just click on the icon Frank mentioned earlier before running the calibration. If you'd like CCDSoft to control the camera (as I used to do all the time before the camera add on became more fully featured), set TheSkyX to use "CCDSoft's Camera" as the camera. I never do plate solves from CCDSoft anymore, that's very clunky!

[White Rabbit]

Are you using "All sky image link" for automated pointing runs? If not and your scope is more a few fields of view off of where it's supposed to the standard image link won't work. I leave "known image scale" unchecked as it seems to work better for me.

[Logieberra]

Paul, with the homing feature of the SB mounts, you only need Sync once. But, should you make any mechanical changes to the mount during polar alignment etc, you'll lose that Sync and will need to do another. If you ever want to clear Syncs, go into Bisque TCS under Sync History and delete them.

Re Image Linking, the standard linking never fails for me. Allsky is a different story. You must know the image scale for Allsky to do its thing. That's the only limitation. Also, because you're permanently mounted in an observatory, I wouldn't even bother with Allsky because standard linking just works so well.

Better add the UCAC4 database as well. Frolimond/Ernie can expand on that.

[gregbradley]

I have done both mainly because using Sky X would fail. Once I had that first plate solve with the north angle it worked.

Thanks for that. I installed the latest daily build and update about 2 weeks ago. Now it won't connect cameras and cannot detect my FLI filter wheel where it could before.

Any suggestions?

Greg.

[PRejto]

Hi Greg,

I suggest that you contact Richard Wright at SB re FLI problem. He is currently quite active on the forum and just answered a similar question regarding FLI (in regards to a current MAC daily build). Your problem might be related to recent changes in both recent daily builds.

Peter

[gregbradley]

Thanks Peter.

I'll have a look at the forum.

Greg.

[Paul Haese]

OK I have SkyX, camera, dome and scope co-operating and plate solving. Doing PA, on my third Run and Ernie you are right it does work. It is very elegant compared to Sky6 with Tpoint mapper. All that was the problem was the sync, did that on Canopus and away it went. Very close to the pole now and just trying to get it to no more adjustments.

[PRejto]

Hi Paul,

When you get "close" it gets tougher to see the improvement because you are making such tiny mechanical adjustments. You might want to photographically measure your movements. To do altitude you can just slew the scope the required # of arcsec away (in the opposite direction), then physically adjust mount until the star is re-centered. I just use a star on the meridian.

Azi is a bit more complicated: (from Patrick Wallace)

"Pick a star on the meridian and as low in the sky as possible. The azimuth adjustment will move the star on the camera in the east-west direction by an angle equal to the adjustment. Note that:
If you have to use a star higher in the sky, the movement on the camera will be smaller by the factor cos(altitude).

If you're not on the meridian the star won't move east-west, but the distance on the camera will be the same."

Thus: if your measurement star is at 40 degrees (altitude) and you need to move azimuth by 1 arcmin: cos(40) x 1 arcmin = .766 arcmin.

I find these methods work so well that I can adjust the mount in a non-iterative process.

Peter