tbaehnck Posted June 11, 2014 Report Share Posted June 11, 2014 Hi Group, could anybody explain me what makes the difference between the two sync methods? When I uses maximdl and make a sync with platesolving (target coordinates are on JNow) and after taht I switch to sequence and made there a sync, I always have a difference. Is this caused by different epochs in sollving the image or something else? In maximdl I always use epoch JNow. Its not a problem because pointing an d tracking are working very well but I like to know whats going on there. Thanks and kind regards Thomas Link to comment Share on other sites More sharing options...
tbaehnck Posted June 16, 2014 Author Report Share Posted June 16, 2014 No Ideas? nobody? I thought I have read something in the old yahoo group but can't find it anymore Link to comment Share on other sites More sharing options...
si6pack Posted June 17, 2014 Report Share Posted June 17, 2014 The only thing I can contribute: I can confirm your observation. May be a little off topic: I investigated this phenomenom with respect to unguided tracking using MLPT...in one attempt I connected via MaximDL to TSX, in the other I connected via MaximDL to "Astrooptik Server Telescope" to receive the initial coordinates for MLPT plate solving in Sequence - result: no difference in tracking accuracy. I also tested different star catalogues as a basis for plate solving - no difference... Unfortunately the weather in southern Germany does not allow additional activities to investigate the underlying difference...in the morning perfectly clear, in the evening clouds are rolling in... Best, Christian Link to comment Share on other sites More sharing options...
tbaehnck Posted November 15, 2015 Author Report Share Posted November 15, 2015 Time runs by. Are there any news or ideas to the above problem? I still wondering why a sync in sequence still find an offset, also if I made a sync in maxim seconds before with the same frame. BR Thomas Link to comment Share on other sites More sharing options...
robertp Posted November 15, 2015 Report Share Posted November 15, 2015 Hello Thomas, your problem reminded me of a conversation I had with Philipp Keller in 2010 were I suspected, that tracking errors might have been related to either using different epochs in TheSky, Maxim, Autoslew and Sequence or by problems in the conversion. Here's a reply that Philipp sent me: "was ganz anderes, ich habe gerade festgestellt, daß MaximDL offensichtlich nicht richtig Current Epoch in 2000 umrechnet.wenn ich in Autoslew 9h, 50 Grad anpositioniere stimmen die Lokal-Koordinaten und Epoch2000 100% mit TheSky überein.MaximDL hat die gleichen JNow, aber 11Bogensekunden Differenz in J2000. Ergo rechnet Maxim anders in 2000 um als ich und TheSky.Das kann natürlich Auswirkungen auf Plate Solves haben. Ich muss der Sache weiter nachgehen.Man sollte jedenfalls keine Differenzen bei MaximDL Platesolves verwenden.Verwende ich den Sequencer umgehe ich das Problem vermutlich dadurch, daß ich selber in Epoch2000 umrechne und PinPoint solven lasse uns dann meine und Pinpoints Epoch2000 vergleiche. Sofern Pinpoint und ich die gleiche Auffassung von Epoch2000 haben sollte es also richtig sein." Basically Philipp indicates that the coordinates in J2000 and Jnow are identical in Autoslew and TheSky, Jnow is also identical in Maxim, but there is a deviation in J2000 in Maxim compared to Autoslew and TheSky. So it might make sense to do some tests with different epoch settings. In my fits-files that were platesolved by PinPoint under MaximDL, the coordinates in the fits-header seem to be J2000. Best regards, Robert Link to comment Share on other sites More sharing options...
tbaehnck Posted November 15, 2015 Author Report Share Posted November 15, 2015 Hi Robert, very interesting. I always use Jnow in Autoslew and also in MaximDL. and if I do a plate solve in Maxim and sync the image centre I check Jnow also. Do you now what Sequence is showing and using when syncing? BR Thomas Link to comment Share on other sites More sharing options...
robertp Posted November 15, 2015 Report Share Posted November 15, 2015 Hi Thomas, I don't know what Sequence is using when syncing. we would have to ask Philipp. I'm not sure if there is another way to find out. I think that Philipp mentioned that he uses Jnow in all places but I have to scan through my emails to verify that. clear skies, Robert Link to comment Share on other sites More sharing options...
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