Function sdssname_radec, ra_sdss, dec_sdss

;+

;NAME:

;     sdssname_radec

;PURPOSE:

;     get SDSS name from RA and DEC for SDSS  PhotoObj position

;INPUT:

;     ra_sdss  ---  RA for SDSS  PhotoObj position in Unit:degree

;     dec_sdss ---  DEC for SDSS  PhotoObj position in Unit:degree

;OUTPUT:

;     sdssname

;REVISION HISTORY:

;     Originla by DL.Wang,Oct-16-2008

;-

if n_elements(ra_sdss) ne  n_elements(dec_sdss) then begin

   print,'please check the number of RA and DEC!!'

   return,-1

endif

num=n_elements(ra_sdss)

sdssname=strarr(num)

for i=0L,num-1 do begin

    ra=sixty(ra_sdss[i]/15.0)

    dec=sixty(dec_sdss[i])

    index=where(dec[0] ge 0,count)

    if count gt 0 then sign='+' else sign='-'

             radec=string(ra[0],format='(I2.2)')+string(ra[1],format='(I2.2)')+strmid(string(ra[2]),strpos(string(ra[2]),'.')-2,2)+'.'+strmid(string(ra[2]),strpos(string(ra[2]),'.')+1,2)+sign+string(dec[0],format='(I2.2)')+string(dec[1],format='(I2.2)')+strmid(string(dec[2]),strpos(string(dec[2]),'.')-2,2)+'.'+strmid(string(dec[2]),strpos(string(dec[2]),'.')+1,1)

    

    sdssname[i]='SDSS J'+strjoin(strsplit(radec,' ',/extract),'0')

endfor

return,sdssname

End