Thought I'd try out the moon images to set the filter balances. I tried a difference image between LUNAR_SCIENCE (CL1,UV3) and 0.8*(CL1,IR1) and get the attached, the white spots are interesting and show more detail than just the brightness.

A linear scaling doesn't get a flat difference over the moon surface and adding an offset just falls out into a constant, I'm guessing there's some non-linearity I'm missing...

I swapped out the WAC red channel for a NIR and the blue for Violet and get the attached image that shows the rings up. I saw some mention of the reflective material identification in the Porco paper but not much. Is there a reference for what each material might give off?

Thanks


Adam

Thankyou for sending a reference, in the end I tracked it down to me being a byte off so the upper word for each pixel was for the pixel before.

Once I got it working I don't see the noise that you have so I think the underlying image is clean.

Thanks again.


Adam

I'm perhaps asking too soon but I'm seeing the artifacts on the attached image of about code 500 and 0. I tried all the endian-ness and signed-ness but this is the least bad of them.

I was just wondering if anyone else had made the same mistake as me?

Many thanks


Adam

This image is from the label file https://pds-imaging.jpl.nasa.gov/w10n/cassi...592133518_1.LBL
and is named N1592133518_1.IMG
the vicar header is below and there is only one segment per line:
{'LBLSIZE': '3216', 'FORMAT': 'HALF', 'TYPE': 'IMAGE', 'BUFSIZ': '20480', 'DIM': '3', 'EOL': '0', 'RECSIZE': '536', 'ORG': 'BSQ', 'NL': '256', 'NS': '256', 'NB': '1', 'N1': '256', 'N2': '256', 'N3': '1', 'N4': '0', 'NBB': '24', 'NLB': '1', 'HOST': 'MAC-OSX', 'INTFMT': 'HIGH', 'REALFMT': 'IEEE', 'BHOST': 'SUN-SOLR', 'BINTFMT': 'HIGH', 'BREALFMT': 'IEEE', 'BLTYPE': 'CAS-ISS4', 'PROPERTY': 'COMPRESSION', 'ANTIBLOOMING_STATE_FLAG': 'OFF', 'CALIBRATION_LAMP_STATE_FLAG': 'N/A', 'DELAYED_READOUT_FLAG': 'NO', 'DETECTOR_TEMPERATURE': '-89.3184', 'EXPOSURE_DURATION': '40.0', 'FILTER_NAME': '(CL1,CL2)', 'FILTER_TEMPERATURE': '0.248629', 'FLIGHT_SOFTWARE_VERSION_ID': '1.4', 'GAIN_MODE_ID': '29 ELECTRONS PER DN', 'INSTRUMENT_DATA_RATE': '365.568', 'INSTRUMENT_MODE_ID': 'SUM4', 'LIGHT_FLOOD_STATE_FLAG': 'ON', 'METHOD_DESC': 'ISSPT2.6.6;Saturn-Rings;ISS_072RI_SPKHRLPDF001_PRIME_2', 'OPTICS_TEMPERATURE': '(0.627499,1.90571)', 'PREPARE_CYCLE_INDEX': '0', 'READOUT_CYCLE_INDEX': '13', 'SENSOR_HEAD_ELEC_TEMPERATURE': '2.34917', 'SHUTTER_MODE_ID': 'NACONLY', 'SHUTTER_STATE_ID': 'ENABLED', 'BIAS_STRIP_MEAN': '145.571', 'DARK_STRIP_MEAN': '97.561', 'DATA_CONVERSION_TYPE': '12BIT', 'MISSING_LINES': '0', 'COMMAND_FILE_NAME': 'trigger_6676_2.ioi', 'COMMAND_SEQUENCE_NUMBER': '6676', 'ELECTRONICS_BIAS': '112', 'ORDER_NUMBER': '66', 'PARALLEL_CLOCK_VOLTAGE_INDEX': '9', 'DATA_SET_ID': 'CO-S-ISSNA/ISSWA-2-EDR-V1.0', 'DESCRIPTION': 'N/A', 'IMAGE_MID_TIME': '2008-166T10:40:49.626Z', 'IMAGE_NUMBER': '1592133518', 'IMAGE_OBSERVATION_TYPE': 'SCIENCE', 'IMAGE_TIME': '2008-166T10:40:49.646Z', 'INSTRUMENT_HOST_NAME': 'CASSINI ORBITER', 'INSTRUMENT_ID': 'ISSNA', 'INSTRUMENT_NAME': 'IMAGING SCIENCE SUBSYSTEM NARROW ANGLE', 'MISSION_NAME': 'CASSINI-HUYGENS', 'MISSION_PHASE_NAME': 'TOUR', 'OBSERVATION_ID': 'ISS_072RI_SPKHRLPDF001_PRIME', 'PRODUCT_CREATION_TIME': '2008-167T02:39:52.000', 'PRODUCT_ID': '1_N1592133518.118', 'PRODUCT_VERSION_TYPE': 'FINAL', 'SEQUENCE_ID': 'S41', 'SEQUENCE_NUMBER': '1004', 'SEQUENCE_TITLE': '--', 'SPACECRAFT_CLOCK_CNT_PARTITION': '1', 'SPACECRAFT_CLOCK_START_COUNT': '1592133518.108', 'SPACECRAFT_CLOCK_STOP_COUNT': '1592133518.118', 'START_TIME': '2008-166T10:40:49.606Z', 'STOP_TIME': '2008-166T10:40:49.646Z', 'TARGET_DESC': 'Saturn-Rings', 'TARGET_LIST': 'N/A', 'TARGET_NAME': 'SATURN', 'EARTH_RECEIVED_START_TIME': '2008-166T23:12:32.754Z', 'EARTH_RECEIVED_STOP_TIME': '2008-166T23:12:35.797Z', 'EXPECTED_PACKETS': '64', 'MISSING_PACKET_FLAG': 'NO', 'RECEIVED_PACKETS': '46', 'SOFTWARE_VERSION_ID': 'ISS 11.00 05-24-2006', 'TELEMETRY_FORMAT_ID': 'S&ER5', 'EXPECTED_MAXIMUM': '(3.95186,69.7116)', 'INST_CMPRS_PARAM': '(N/A,N/A,N/A,N/A)', 'INST_CMPRS_RATE': '(6.95652,4.85864)', 'INST_CMPRS_RATIO': '3.2931', 'INST_CMPRS_TYPE': 'LOSSLESS', 'VALID_MAXIMUM': '(6250,4095)', 'TASK': 'COPY', 'USER': 'diehl', 'DAT_TIM': 'Mon Mar 16 16:39:55 2009'}

I'm running through the images to figure out what's what and I'm stuck when I get to image N1875522952_1 in the extended_extended set.

The image is taken at spacecraft clock 11875522951.118 (the .LBL file suggests this is 08/06/2017at 09:26 however SPICE suggests 07/06/2017 09:28, I'm using this) and I tried loading the following positional kernels which I picked out as the latest versions of PE,SK and SCPSE types of SPK kernels with .LBL date spans that cover the spacecraft clock time:
170619AP_PE_17166_17258.bsp
170619AP_SK_17166_17258.bsp
200128RU_SCPSE_17126_17158.bsp

When I try to get the position (spice.spkpos('Cassini', et, 'J2000', 'NONE', 'SATURN')) I get the following message suggesting I'm not loading the right position kernels.

================================================================================

Toolkit version: CSPICE66

SPICE(SPKINSUFFDATA) --

Insufficient ephemeris data has been loaded to compute the position of -82 (CASSINI) relative to 699 (SATURN) at the ephemeris epoch 2017 JUN 07 09:28:08.127.

spkpos_c --> SPKPOS --> SPKEZP --> SPKGPS

================================================================================

What SPK kernels would you expect for this time point?

Just for completeness the other kernels I'm using are (though I probably only need LSK and SCLK for this query):
LSK (leap seconds) : naif0012.tls.pc
SCLK (spacecraft clock) : cas00172.tsc
PCK (planetary constants) : cpck15Dec2017.tpc
FK (reference frames) : cas_v39.tf
IK (instrument geometry) : cas_iss_v10.ti [Imaging Sub System only]

Many thanks


Adam

Awesome, thanks.

I see SPICE kernels in two different places:

https://naif.jpl.nasa.gov/pub/naif/CASSINI/kernels/
https://naif.jpl.nasa.gov/pub/naif/pds/data...cosp_1000/data/

They don't match up, does anyone know which would be the recommended set to look at?

Many thanks

The top edge of the second image looks a little bit off, it makes me think there's some close in phase noise. I feel like just a bit of offset makes the image less clear.

JNCE_2016287_02C10029_V01 and JNCE_2016346_03C00111_V01

Feel like I should be cross correlating the framelets to line them up better.

first elements in pds-imaging.jpl.nasa.gov/data/juno/JNOJNC_0003 ... ORBIT_03 distances (*1e6)

Distance
JNCR_2016345_03C00002_V01 1.4749159628193276
JNCR_2016345_03C00004_V01 1.4542690337823034
JNCR_2016345_03C00006_V01 1.433096928709612
JNCR_2016345_03C00008_V01 1.4120987115862533
JNCR_2016345_03C00010_V01 1.3909172905039227
JNCR_2016345_03C00012_V01 1.3691855981815069
JNCR_2016345_03C00014_V01 1.347621178250636
JNCR_2016345_03C00016_V01 1.3258587513481361
JNCR_2016345_03C00018_V01 1.3035162684580093
JNCR_2016345_03C00020_V01 1.281332622460322
JNCR_2016345_03C00022_V01 1.258932568679058
JNCR_2016345_03C00024_V01 1.2359197889265243
JNCR_2016345_03C00026_V01 1.213055075385369
JNCR_2016345_03C00028_V01 1.1899475527741066
JNCR_2016345_03M00003_V01 1.474567901189406
JNCR_2016345_03M00005_V01 1.4539189089308011
JNCR_2016345_03M00007_V01 1.4327428910711637
JNCR_2016345_03M00009_V01 1.411741356989429
JNCR_2016345_03M00011_V01 1.3905564343494536
JNCR_2016345_03M00013_V01 1.3688215557054952
JNCR_2016345_03M00015_V01 1.3472543814410143
JNCR_2016345_03M00017_V01 1.3254885364143894
JNCR_2016345_03M00019_V01 1.303143190126758
JNCR_2016345_03M00021_V01 1.2809550341508031
JNCR_2016345_03M00023_V01 1.2585506280431125
JNCR_2016345_03M00025_V01 1.2355339342131775
JNCR_2016345_03M00027_V01 1.2126652365486847
JNCR_2016345_03M00029_V01 1.189553484512732
JNCR_2016346_03C00030_V01 1.1661912642390564
JNCR_2016346_03C00032_V01 1.142569958698268
JNCR_2016346_03C00034_V01 1.1186770336070144
JNCR_2016346_03C00036_V01 1.0940900489924803
JNCR_2016346_03C00038_V01 1.0696176680119247
JNCR_2016346_03C00040_V01 1.0448411858717241
JNCR_2016346_03C00042_V01 1.0193164498691287
JNCR_2016346_03C00044_V01 0.9938807940272427
JNCR_2016346_03C00046_V01 0.9680960300454893
JNCR_2016346_03C00048_V01 0.9414980153906513
JNCR_2016346_03C00050_V01 0.914954042991846
JNCR_2016346_03C00052_V01 0.8880069755317854
JNCR_2016346_03C00054_V01 0.8601663083791415
JNCR_2016346_03C00056_V01 0.8323272173692047
JNCR_2016346_03C00058_V01 0.8040060556871191
JNCR_2016346_03C00060_V01 0.7746816622971828
JNCR_2016346_03C00062_V01 0.7452942366063703
JNCR_2016346_03C00064_V01 0.7153205627158753
JNCR_2016346_03C00066_V01 0.6841949702467771
JNCR_2016346_03C00068_V01 0.6529050339205971
JNCR_2016346_03C00070_V01 0.6208765966200915
JNCR_2016346_03C00072_V01 0.5874879058629068
JNCR_2016346_03C00074_V01 0.5537655188369682
JNCR_2016346_03C00076_V01 0.5184797286441235
JNCR_2016346_03C00078_V01 0.4826962078365891
JNCR_2016346_03C00080_V01 0.44571389822537527
JNCR_2016346_03C00082_V01 0.4066968543196093
JNCR_2016346_03C00084_V01 0.36676121751055313
JNCR_2016346_03C00086_V01 0.32502963200448337
JNCR_2016346_03C00088_V01 0.28046415051659923
JNCR_2016346_03C00090_V01 0.23421622415802842
JNCR_2016346_03C00092_V01 0.18534662412401262
JNCR_2016346_03C00094_V01 0.16306171187805069
JNCR_2016346_03C00099_V01 0.13625314711450223
JNCR_2016346_03C00101_V01 0.11756522363165459
JNCR_2016346_03C00103_V01 0.1126320048233185
JNCR_2016346_03C00104_V01 0.1078072608199902
JNCR_2016346_03C00105_V01 0.10159556219787719
JNCR_2016346_03C00107_V01 0.08554410309594325
JNCR_2016346_03C00109_V01 0.07728393319740363
JNCR_2016346_03C00110_V01 0.07611334234562364
JNCR_2016346_03C00111_V01 0.07562709329795922
JNCR_2016346_03C00113_V01 0.07677904939741823
JNCR_2016346_03C00114_V01 0.07977995034288528
JNCR_2016346_03C00116_V01 0.08775202559754502
JNCR_2016346_03C00117_V01 0.09353508642276395
JNCR_2016346_03C00118_V01 0.10532699656020048
JNCR_2016346_03C00120_V01 0.11333557087096598
JNCR_2016346_03C00121_V01 0.11996486070527151
JNCR_2016346_03C00122_V01 0.13701459737163593
JNCR_2016346_03C00124_V01 0.15433758744021367
JNCR_2016346_03C00126_V01 0.16557303244056495
JNCR_2016346_03C00131_V01 0.19796182500155401
JNCR_2016346_03C00133_V01 0.24697405149025134
JNCR_2016346_03C00135_V01 0.2547492157259101
JNCR_2016346_03C00136_V01 0.2925490269964357
JNCR_2016346_03C00138_V01 0.33580497605848353
JNCR_2016346_03C00140_V01 0.37773203892274115
JNCR_2016346_03C00142_V01 0.4172199339771325
JNCR_2016346_03C00144_V01 0.4552089060272889
JNCR_2016346_03C00146_V01 0.4924935369415306
JNCR_2016346_03C00148_V01 0.5279726846401707
JNCR_2016346_03C00150_V01 0.56240278244829
JNCR_2016346_03M00031_V01 1.165794069594665
JNCR_2016346_03M00033_V01 1.1421667216261628
JNCR_2016346_03M00035_V01 1.1182692205285651
JNCR_2016346_03M00037_V01 1.0936774416414148
JNCR_2016346_03M00039_V01 1.0692007386974487
JNCR_2016346_03M00041_V01 1.044418319134217
JNCR_2016346_03M00043_V01 1.0188886196330889
JNCR_2016346_03M00045_V01 0.9934465113259777
JNCR_2016346_03M00047_V01 0.9676556780735772
JNCR_2016346_03M00049_V01 0.9410517549823207
JNCR_2016346_03M00051_V01 0.9145027155910714
JNCR_2016346_03M00053_V01 0.8875444582811646
JNCR_2016346_03M00055_V01 0.8596980850406111
JNCR_2016346_03M00057_V01 0.8318513144736257
JNCR_2016346_03M00059_V01 0.8035229258727051
JNCR_2016346_03M00061_V01 0.7741886760422414
JNCR_2016346_03M00063_V01 0.7447903792979518
JNCR_2016346_03M00065_V01 0.7148085930618021
JNCR_2016346_03M00067_V01 0.6836718404508733
JNCR_2016346_03M00069_V01 0.6523666453799356
JNCR_2016346_03M00071_V01 0.6203286938241885
JNCR_2016346_03M00073_V01 0.5869229741636646
JNCR_2016346_03M00075_V01 0.5531871673635312
JNCR_2016346_03M00077_V01 0.5178840441364595
JNCR_2016346_03M00079_V01 0.48207959175043824
JNCR_2016346_03M00081_V01 0.4450741692733699
JNCR_2016346_03M00083_V01 0.4060335919027028
JNCR_2016346_03M00085_V01 0.3660687365228705
JNCR_2016346_03M00087_V01 0.3243076858206185
JNCR_2016346_03M00089_V01 0.27893943183466036
JNCR_2016346_03M00091_V01 0.23260218791056403
JNCR_2016346_03M00093_V01 0.18364601984059728
JNCR_2016346_03M00095_V01 0.16133280775431164
JNCR_2016346_03M00100_V01 0.13453254658555008
JNCR_2016346_03M00102_V01 0.11590680065317674
JNCR_2016346_03M00106_V01 0.09934668091407667
JNCR_2016346_03M00108_V01 0.08393500196766686
JNCR_2016346_03M00115_V01 0.08100107411841447
JNCR_2016346_03M00119_V01 0.10768535645858862
JNCR_2016346_03M00123_V01 0.13873822972177044
JNCR_2016346_03M00125_V01 0.15606896605801074
JNCR_2016346_03M00127_V01 0.16729564335748212
JNCR_2016346_03M00132_V01 0.19964066999198055
JNCR_2016346_03M00134_V01 0.2485585937247511
JNCR_2016346_03M00137_V01 0.29405202377776174
JNCR_2016346_03M00139_V01 0.33652083987186676
JNCR_2016346_03M00141_V01 0.378414848080696
JNCR_2016346_03M00143_V01 0.4178767405847803
JNCR_2016346_03M00145_V01 0.4558409140118276
JNCR_2016346_03M00147_V01 0.4931068685535241
JNCR_2016346_03M00149_V01 0.5285654844800145
JNCR_2016346_03M00151_V01 0.5629791194301715
JNCR_2016346_03R00096_V01 0.14748613797475552
JNCR_2016346_03R00097_V01 0.1440213925262166
JNCR_2016346_03R00098_V01 0.14056038511346425
JNCR_2016346_03R00112_V01 0.07578346112862916
JNCR_2016346_03R00128_V01 0.16902926300647367
JNCR_2016346_03R00129_V01 0.1724656342471787
JNCR_2016346_03R00130_V01 0.1758954209927151
JNCR_2016347_03C00152_V01 0.7824134559147339
JNCR_2016347_03C00154_V01 0.8112195631929505
JNCR_2016347_03C00156_V01 0.8395178236038593
JNCR_2016347_03C00158_V01 0.8673390402986039
JNCR_2016347_03C00160_V01 0.8947094872451112
JNCR_2016347_03C00162_V01 0.9216551000589288
JNCR_2016347_03C00164_V01 0.9486419853843271
JNCR_2016347_03C00166_V01 0.9747931491747635
JNCR_2016347_03C00168_V01 1.0005793398456964
JNCR_2016347_03C00170_V01 1.026018510050173
JNCR_2016347_03C00172_V01 1.051124551096523
JNCR_2016347_03C00174_V01 1.0759141472704186
JNCR_2016347_03C00176_V01 1.1003973985817903
JNCR_2016347_03C00178_V01 1.1245910718049865
JNCR_2016347_03C00180_V01 1.1485020228105907
JNCR_2016347_03C00182_V01 1.1725436487611736
JNCR_2016347_03C00184_V01 1.1959205608674668
JNCR_2016347_03C00186_V01 1.219047583471167
JNCR_2016347_03C00188_V01 1.2419344515592095
JNCR_2016347_03C00190_V01 1.2645863578144523
JNCR_2016347_03C00192_V01 1.2870143376319843
JNCR_2016347_03C00194_V01 1.3092217379324087
JNCR_2016347_03C00196_V01 1.3312199262013584
JNCR_2016347_03C00198_V01 1.353010762400183
JNCR_2016347_03C00200_V01 1.3749692819343315
JNCR_2016347_03C00202_V01 1.3963669459657848
JNCR_2016347_03C00204_V01 1.417575972784607
JNCR_2016347_03C00206_V01 1.4386028647847846
JNCR_2016347_03C00208_V01 1.459453462158997
JNCR_2016347_03C00210_V01 1.4801315455961337
JNCR_2016347_03C00212_V01 1.5006421242940555
JNCR_2016347_03C00214_V01 1.5209890132147317
JNCR_2016347_03C00216_V01 1.5411761095253764
JNCR_2016347_03C00218_V01 1.5615450962412931
JNCR_2016347_03C00220_V01 1.5814223988183262

Contents of pds-imaging.jpl.nasa.gov/data/juno/JNOJNC_0002

I'm looking at post number 81 in this thread from Gerald and I don't understand the goal of the operation. I see color banding referred to, I'm assuming this is the post decompanded quantization artifacts? Is this from an operation referred to elsewhere?

Many Thanks.

The closer (and so more polar) JNCE_2016240_01C06159_V01 along with JNCE_2016240_01C06151_V01 which has a fun bonus moon in there!

Thanks guys, apparently I'm a goose. I hard coded the inter frame delay from that P8 image I was looking at before (my code is only a couple hundred lines long so it's a bit bare bones) and this one is different by 8ms.

How are peoples' inter frame delays looking?

In the attached images for JNCE_2016239_01C06109_V01 I added the recommended 1ms inter frame delay (right) and also tried 10ms (left) that got it looking better but not perfect. It's probably not right adding this accumulating delay and seems more likely to be some offset between the three colours instead which is why I ask.

I did see jitter mentioned but I tried a couple of images and the error seems similar between them so it does seem systematic.

Just having alook to see what's in the dataset for P1, putting this here for anyone else who's 23 apojoves behind the curve too. Pulled all the LBL files from pds-imaging and used the spacecraft clock to figure out J2000 frame position. Looking along the X axis (because this one's pretty flat) the Juno locations (divided by 1e6) for each LBL file are marked by dots coloured by spacecraft time.

Just to note, it's under https://pds-imaging.jpl.nasa.gov/data/juno/...PITER/ORBIT_01/ where ORBIT_00 is a bundle of very similar positions.

Interesting, [1,1.23,2.66] I actually dropped my 0.95 so I think you nailed it.

mcaplinger, sorry I didn't spot your name on the technical report, that was pretty lazy of me! Congratulations on such a successful piece of hardware, as an electronics guy it's the camera itself that's got me interested, I've been very impressed.

The RDR data set says "For planetary targets, these values are then scaled such that a white surface at the solar distance at the time of imaging and with the commanded exposure time would have a pixel value of 10,000 data numbers.", so I'm assuming the blue already got scaled before I got to it. I probably ought to use the EDR data set if I want to actually know how it got scaled.

Regarding sRGB, it seems sensible to me that you can scale the linear raw IMG which is what I'm doing but should I be trasforming to sRGB at some point?

Sounds like I'm miles off for some reason. I used the RDR product assuming it had already been decompanded, I recall I have a range to 4kish so it has certainly been through something.

Anyone have any good advice on scaling the RGB to give the closest to true color? I tried these two [0.487, 0.408, 0.172] [0.444, 0.341, 0.155] from Brian's flow and I get a strong orange hue. I also tried the coefficients [0.51, 0.63, 1.0] from Gerald's slides and it comes out pretty blue looking. I tried a few and felt like [1,1,0.95] seemed close but I've only seen artistically processed images from Junocam processing that look so different to pictures of Jupiter, I simply don't know any more!

Many Thanks

Tried doing color, seems to work. The KD tree was way too slow so I just idiot histogrammed it. I probably need a hit count pass to clean it a bit but it'll do for now. Thanks for the help.

Took a while. It wasn't light travel time because the error introduced is too small. It was that I tried hand fitting the limb which gave a timing error which gave an angle offset from the spacecraft spin. So doing a limb search got the timing to line up. I scaled everything by its dot product to the Jupiter vector so it ended up on a plane. I dropped the extra dimension by taking the first row as one basis vector and then taking a column as another vector, made it orthonormal then projected everyting onto those vectors. It gave the first picture and I did a KD nearest neigbour search to rasterize it, second image. I kind of like the projection to a plane as I feel it makes it more like a real single camera, at least it'll behave just like a pinhole camera.

The projection to an imaginary Juno centered sphere is nice because it doesn't need any spice ray projections so takes no time and as I'm unprojecting it from the same point of view the Jupiter mapping bit isn't actually doing anything (other than some super serious finding of errors!). I feel the sphere project -> plane -> dimension reduction can easily be made into a single stage so you wouldn't actually have to do the imaginary sphere thing (Though honesty it's not that bad as it is). That should get it way faster than what I have so then a super simple pipeline can use all the hard work that went into the SPICE kernels to make nicely stitched pictures. I'm sure the nearest neighbour search can be improved on too because the data has structure so you always know which direction will get you closer, anyone know of an implementation of such a thing?

Update: I think my issue is that the transform doesn't do light stuff which I was assuming. So the first has apparent position and the second doesn't. I've tried shifting everything by the difference between the corrected and uncorrected limb to get it equivalent to the apparent poisition but not luck yet :-/
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I've been looking at this pretty carefully and I'm not seeing my error, when I map this back to the juno location it comes out evenly spaced (so I'm mapping back to the same spot) but there's a gap. So the result from one branch is being mapped a little bit off the other. If someone could give me a hint that would be great. I used the LT method thinking it would match method wise but I tried a few and it makes very little difference.

Thanks for any help.

I tried the limbpt function (below), not that I really understand the half plane thing, hence stuffing the same z vector in that the example code has. It kind of lines up, I added the points it returns as red and the view is from the underside, I'm assuming that the difference is from the non-roundness of the planet.

limbRet = spice.limbpt('TANGENT/ELLIPSOID','JUPITER',et0,'IAU_JUPITER','LT+S','CENTER','JUNO',[0.0,0.0,0.1],0.01,100,1e-4,1e-6,100)

Thanks mcaplinger, I've changed it to the following, with the terrible frac in there to line the sphere thing up with the visible edge, I think you can tell what I'm up to from the plot now.

[jupiterPos, jupiterLt] = spice.spkpos('JUPITER', et0, 'IAU_JUPITER', 'NONE', 'JUNO')
pos = frac*direction*jupiterDistance/np.linalg.norm(direction)
rotationMatrix = spice.pxfrm2('JUNO_JUNOCAM','IAU_JUPITER',et, et-jupiterLt*frac)
pos = spice.mxv(rotationMatrix, pos)
pos -= jupiterPos

I've reasoned that the first pos assignment gets where it should be in the camera frame, the rotation does all the light time magic and the subtraction gets the resulting vector translated to Jupiter. It seems to work but it would be comforting if someone could say if this is nonsense that worked by chance. My use of the word "magic" gives an idea of my proficiency in these things.

I switched to the juno_sc_rec_170831_170902_v01.bc kernel like you said and I had to add 10ms to get the edge to line up which agrees with what you said earlier.

Brian, I see your code uses limbpt to find the limb, is that the easiest way do you think?

Many thanks


Adam