SharpCap Forums

Hi

I'm having this "strange" situation with plate solve.
I wanted to try calibrating the color (using livestack) of a previously captured FIT and encountered this problem.

Test camera 1 Deep sky
Load my FIT

Menu / Tools / Plate solve: ok
Livestack / Color calibration / Calibrate: not solved

Same error if I use the command in a sequence: MOUNT SOLVEANDSYNC
Same error using Hardware / select mount / none
but using Menu /tools /plate solve is ok


Please note that the FIT header already contains all the data previously saved by both SharpCap and Astap. I'm attaching the FIT header if it's helpful.



SIMPLE = T / C# FITS: 06/25/2025 00:15:14
BITPIX = -32 / Bits per entry
NAXIS = 3 / Number of dimensions
NAXIS1 = 3008 / length of x axis
NAXIS2 = 3008 / length of y axis
NAXIS3 = 3 / length of z axis (mostly colors)
OFFSET = 35 /
OBJECT = 'NGC4490' /
GAIN = 300 /
FILTER = 'IR' /
EQUINOX = 2025.4809781042552 /
OBJCTDEC= '+41 30 19.000' / Epoch : JNOW
RA = 187.964577317529 / Epoch : JNOW
DEC = 41.5054566291875 / Epoch : JNOW
BLKLEVEL= 35 /
FOCALLEN= 661.2 /
OBSLONG = 10.7661111111111 /
OBSLAT = 43.8861111111111 /
OBJCTRA = '12 31 51.000' / Epoch : JNOW
SUBEXP = 15 /
OBJCTALT= 40.1677453434302 /
PIERSIDE= 'EAST' /
CD2_2 = 0.000302886969 /
OBJCTAZ = 293.052899519503 /
AIRMASS = 1.547454902023025 / Pickerings formula from target elevation only.
EGAIN = 0.1021 / Electrons per ADU at true ADC bit depth
ADCBITS = 14 / Bit depth of camera sensor ADC in current mode
BIASADU = 1360 / ADU for bias level (no photons) at current sett
EGAINSAV= 0.02553 / Electrons per ADU at saved bit depth
RELGAIN = 30.419 / Multiplicative gain relative to minumum
RDNOISE = 1.25 / Read noise in electrons
INSTRUME= 'ZWO ASI533MC Pro' /
TELESCOP= 'ASTRO-PHYSICS 105 TRAVELER EDF'
CAMID = '2A34CD0303010900' /
CD2_1 = 0.000120162964 /
CROTA2 = 21.743793324418476 / Rotation of image (deg - up is east-of-north)
CD1_1 = 0.000302538567 /
EXTEND = T / Extensions are permitted
BZERO = 0 / physical_value = BZERO + BSCALE * array_value
BSCALE = 1 / physical_value = BZERO + BSCALE * array_value
ROWORDER= 'TOP-DOWN' /
XPIXSZ = 3.76 / microns, includes binning if any
YPIXSZ = 3.76 / microns, includes binning if any
XBINNING= 1 /
YBINNING= 1 /
COLORTYP= 'RGB' /
SWCREATE= 'SharpCap v4.1.13417.0, 64 bit' /
DATE-OBS= '2025-06-24T21:09:46'/ Date and time of the start of the observation.
CD1_2 = -0.000120801611 /
DATE-END= '2025-06-24T22:46:06'/ Date and time of the end of the observation.
JD_UTC = 2460851.421787762 / Julian Date at mid exposure
PLTSOLVD= 'Astrometric Solution by SharpCap SharpSolve 4.1.13417.0' /
CTYPE1 = 'RA---TAN' / Tangential projection of RA
CTYPE2 = 'DEC--TAN' / Tangential Projection of Declination
CUNIT1 = 'deg' /
CRPIX1 = 1504 / Reference Pixel X Co-ordinate
CRPIX2 = 1504 / Reference Pixel Y Co-ordinate
CRVAL1 = 187.65438079833984 / Reference Pixel RA (deg)
CRVAL2 = 41.64178466796875 / Reference Pixel Dec (deg)
CDELT1 = 0.000325806466 / X Pixel Size (deg)
CDELT2 = 0.000325806466 / Y Pixel Size (deg)
CROTA1 = 21.743793324418476 / Rotation of image (deg - up is east-of-north)
OBSERVER= 'Dott. Carlo Muccini'
DATE-AVG= '2025-06-24T22:07:22.4626583' / System Clock:Est. Frame Mid Point
FLAT = 'AP'
COMMENT 1 Written by ASTAP. www.hnsky.org
PEDESTAL= 2118 / Value added during calibration or stacking
CALSTAT = 'S'
ISSUES = ''
HISTORY 1 Stacking method SIGMA CLIP AVERAGE
HISTORY 2 Combined to colour image.
SET-TEMP= -5 / Average set temperature used for luminance.
LUM_EXP = 900 / Average luminance exposure time.
LUM_CNT = 6 / Luminance images combined.
LUM_DARK= 0 / Darks used for luminance.
LUM_FLAT= 0 / Flats used for luminance.
LUM_BIAS= 0 / Flat-darks used for luminance.
DATAMIN = 0 / Minimum data value
DATAMAX = 64187 / Maximum data value
CBLACK = 1714 / Black point used for displaying image.
CWHITE = 2270 / White point used for displaying the image.
END



Carlo

Hi Carlo,

looking at the various co-ordinates shown in the screenshot, I can see that the position being used for the attempt to plate solve in the calibration area is the same as the position shown in the 'Telescope.Net Simulator' on the right, which was disconnected at the time you posted the screenshot. However, the plate solve location for the image is totally different - 3 hours of RA and 50 degrees of declination different.

The way that the colour calibration gets the information about where to start its plate solving attempt is that first it asks the live stack if that has a set of co-ordinates recorded, and if not it asks the connected mount. The live stack takes it's internal set of co-ordinates from the mount co-ordinates at the first frame, so it seems likely that the Telescope.NET simulator was connected when you started the live stacking, which let the mount co-ordinates get stored at that point and then used later for the calibration.

In real sky use, this will not cause an issue, but it is here in the test camera or folder monitor camera with the simlated mount pointing in a completely different place to the actual location of the image.

I think the best bet here is to leave things the way they are, but if the plate solve inside calibration fails based on the calculated center co-ordinates, retry with a full sky search. That second phase would only kick in for the sort of situation you are in, so it won't affect real sky usage.

In the current version of SharpCap, just make sure the mount is disconnected and reset the stack - that should clear the internal cached set of co-ordinates, which means that if you then try to calibrate it will not be able to work out a center location, so it will do a whole sky search anyway.

cheers,

Robin

Thanks for the advice.
I confirm that without the simulator, Telescope.net, the color calibration works perfectly.

Carlo