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Nexstar Hand Controller–WRONG COORDINATES

Celestron
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#1 mbolen

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Posted 15 February 2020 - 04:41 PM

Hello, I recently tried to image the Witch Head Nebula. My setup isn’t complicated—no computer for plate solving or guiding. I use the hand controller to polar align, and use Precise Go-to to center my object for shooting. I recently found that the location for NGC 1909 (Which Head Nebula) is not correct in the database. It points to the following location—RA: 05h 25’ 29” DEC: -08° 14’ 10”, while Witch Head is actually at this location: RA: 05h 05’ 53” DEC: -07° 05’ 14”. My question is how many other objects have the wrong coordinates? Is this a common occurrence? I haven’t had trouble with any other object. Is there a way to report the error? I wasted several clear nights before I figured this out!

#2 scopewizard

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Posted 15 February 2020 - 05:00 PM

Have you tried setting ngc 1909 instead .



#3 sg6

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Posted 15 February 2020 - 05:09 PM

The coordinates are I believe updated every year, even more often if I read Skysafari right - probably don't however.

Skysafari says: RA 05  07  51.64, Dec: -07 11 30.3, with an apparent date of 2020.1

 

The "standard" time to determine RA+Dec is the moment of the Spring Equinox.

Which this year is: Friday, 20 March 2020, 03:49 UTC

 

Changes are caused by our egg shaped orbit and precession. So basically each year things move and the Celestron is likely old data. A fairly common standard is 2000. So you are likely several years out of date.

 

I suppose if it has a reasonable size then where do you take the measurement at - center, left, right.

 

Need to stop assumng all that you read on the handset is utterly correct. Also who's data was used? Bet there are a few RA+Dec data sets around and likely all a little different.

 

Wiki says RA: 05 02 00 and Dec: -7 54 0

 

That is 3 and each different.


Edited by sg6, 15 February 2020 - 05:15 PM.


#4 mbolen

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Posted 15 February 2020 - 05:42 PM

A few things:
(1)The “Witch Head Nebula” wasn’t there, so I only used NGC 1909 to slew to it.
(2) My hand controller hasn’t been updated for a while, but I have been using this method for both observing and astrophotography for several years now and have never had an issue like this before. Further, I was able to successfully slew to a bunch of different objects that same night. Just not NGC 1909.
(3) After using the coordinates I found on telescopious.com, I was able to hit the target dead on.

Edited by mbolen, 15 February 2020 - 05:43 PM.


#5 dcollier

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Posted 15 February 2020 - 06:04 PM

http://simbad.u-stra...Ident=NGC 1909

 

This is the definitive source, also Celestron HCs Use JNow coordinates.  So precessed coordinates would be 05h 02' 59"  -7 52' 19" for today.   This also checks in Stellarium. 

 

         -Dave




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