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Help with Plate Solving

dradford's picture
Joined: 2013-02-21


Hi All

I am a nebie having just started to use VShot.

I have been able to upload images with the Wizard and Quick load but cannot get the images to plate solve.

I took some images of R Car , and I am certian it is sitting directly in the middle of the field. I had to enter the RA/DEC fiquers manually into the Fits header as Image plus doesn't enter then automatically from Stellarium. I entereed the RA/DEC J2000 numbers as below at the time the shot was taken. I also chnged the time to UTC as it had entered local time.

I know there will be issues with the QHY10 colour camera and have uploaded a grey and green only file.

Fits header below

Any suggestions were I'm going wrong? Thankyou


Don Radford obs ID RDJA


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FITS Header of Image  634994826059683750.fts

Key Value Comment
SIMPLE T file does conform to FITS standard
BITPIX 16 number of bits per data pixel
NAXIS 2 number of data axes
NAXIS1 2610 length of data axis 1
NAXIS2 3894 length of data axis 2
EXTEND T FITS dataset may contain extensions
COMMENT FITS (Flexible Image Transport System) format is defined in 'Astronomy
COMMENT and Astrophysics', volume 376, page 359; bibcode: 2001A&A...376..359H
BZERO 32768 offset data range to that of unsigned short
BSCALE 1 default scaling factor
COMMENT and Astrophysics', volume 376, page 359; bibcode: 2001A&A...376..359H
COMMENT and Astrophysics', volume 376, page 359; bibcode: 2001A&A...376..359H
CREATOR ImagesPlus Camera Control Software created file
DATE-OBS 2013-03-21T09:53:36 [ISO 8601] UTC date/time of exposure start
DATE 21 03/13' / [old format] UTC date of exposure start
INSTRUME QHYCCD QHY10 S N' / Detector instrument name
OBJECT R Car Target object name
IMAGETYP Light Image Type
FILTER V Filter name
EXPOSURE 5.00000000000E+000 [sec] Duration of exposure
SET-TEMP -20. CCD target temperature in C
CCD-TEMP -20.457 CCD temperature in C
OFFSET 0 Camera Offset
XBIN 1 X Bin Mode
YBIN 1 Y Bin Mode
XPIXSIZE 6.05 X Pixel Size
YPIXSIZE 6.05 Y Pixel Size
APERTURE 0. Telescope aperture in mm
FOCALEN 0. Focal length in mm
OBJCTRA 16 44 42.60 [hms J2000] Target right ascension
OBJCTDEC -40 50 23.1 [dms +N J2000] Target declination
AIRMASS 1.34779496267E+000  
EPOCH 2000  
TELESCOP Meade Imageplus' / Telescope name
EGAIN 0.450  
LMAXADU 50000.000  
ALT-OBS 4.00000000000E+001 [metres] Altitude above mean sea level
LONG-OBS 1.52896000000E+002 [deg +E WGS84] Geodetic longitude
HISTORY File was processed by PinPoint 5.1.8 at 2013-03-22T00:10:05
EXPTIME 5.00000000000E+000 [sec] Duration of exposure
TIME-OBS 09:53:36 [old format] UTC time of exposure start
UT 09:53:36 [old format] UTC time of exposure start
TIMESYS UTC Default time system
RADECSYS FK5 Equatorial coordinate system
RA 16 44 42.60 [hms J2000] Target right ascension
DEC -40 50 23.1 [dms +N J2000] Target declination
CLRBAND R [J-C std] Std. color band of image or C=Color
HISTORY File was processed by PinPoint 5.1.8 at 2013-03-22T00:17:52
FWHM 9.50134776980E+000 [pixels] Mean Full-Width-Half-Max of image star

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I'd like to know too
uis01's picture
Joined: 2010-07-25

I'll admit that I never correctly deciphered what VPHOT needs to do a good plate solution for my telescope so I have beenn running all my images through before uploading them.  I'd also like to see some more detailed technical help posted about this.

Plate solving
HBB's picture
Joined: 2010-07-24

I use Pinpoint with Maxim and it requires Pixel scale so it needs your focal length of the telescope along with pixel size.  I notice that focal length is not given in your fits file.   

Barbara (HBB)

Plate Solving
TCB168's picture
Joined: 2010-07-26

You dont have to have the scope details in the fits header but you do need the RA and Dec.

You first have to work out the plate scale for your images. You can do this by uploading an image to and let it plate solve an image. It will then give you a plate scale. My current setup gives 1.56arcsec/pixel. Yours will be different but should be a number between about 0.5 and 5.

You then have to create your telescope in VPhot. Go to the 'admin' tab and click on "telescope setup".
From there you select "create new teslescope setup"

Enter a name and fill in the boxes. Once you have done this you can upload an image using your telescope setup and it should plate solve.

Good luck


Fixed Mine... Might Help With Yours
uis01's picture
Joined: 2010-07-25

I think I know what might really be wrong with this header because it was missing from my FITS headers also.  And when I added it in:  problem fixed.

This was the web page that helped me figure it out:

It turns out that Pinpoint needs the FITS header keywords CDELT1 and CDELT2 to contain the size of the CCD pixels (in arcseconds!) on the X (cdelt1) and Y (cdelt2) axes of the CCD.  Once I added those to my headers, Pinpoint in VPHOT was all green lights for me.  

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