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        <InvestmentEarningsOrLossesAmt>-3278583</InvestmentEarningsOrLossesAmt>
        <AdministrativeExpensesAmt>93731</AdministrativeExpensesAmt>
        <EndYearBalanceAmt>30718750</EndYearBalanceAmt>
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        <BeginningYearBalanceAmt>27582910</BeginningYearBalanceAmt>
        <ContributionsAmt>3500000</ContributionsAmt>
        <InvestmentEarningsOrLossesAmt>2660684</InvestmentEarningsOrLossesAmt>
        <AdministrativeExpensesAmt>72074</AdministrativeExpensesAmt>
        <EndYearBalanceAmt>33671520</EndYearBalanceAmt>
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        <AdministrativeExpensesAmt>74348</AdministrativeExpensesAmt>
        <EndYearBalanceAmt>27582910</EndYearBalanceAmt>
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        <BeginningYearBalanceAmt>21493670</BeginningYearBalanceAmt>
        <ContributionsAmt>644390</ContributionsAmt>
        <InvestmentEarningsOrLossesAmt>3026659</InvestmentEarningsOrLossesAmt>
        <AdministrativeExpensesAmt>80102</AdministrativeExpensesAmt>
        <EndYearBalanceAmt>25084617</EndYearBalanceAmt>
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        <BeginningYearBalanceAmt>28452867</BeginningYearBalanceAmt>
        <InvestmentEarningsOrLossesAmt>-1462158</InvestmentEarningsOrLossesAmt>
        <GrantsOrScholarshipsAmt>5400000</GrantsOrScholarshipsAmt>
        <AdministrativeExpensesAmt>97039</AdministrativeExpensesAmt>
        <EndYearBalanceAmt>21493670</EndYearBalanceAmt>
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      <PrmnntEndowmentBalanceEOYPct>0.00000</PrmnntEndowmentBalanceEOYPct>
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      <TotalBookValueOtherAssetsAmt>13542420</TotalBookValueOtherAssetsAmt>
      <FootnoteTextInd>X</FootnoteTextInd>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>PART V, LINE 4:</FormAndLineReferenceDesc>
        <ExplanationTxt>THE ENDOWMENT FUNDS ARE USED FOR SUPPORT OF LOWELL OBSERVATORY AND FOR REINVESTMENT.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>PART X, LINE 2:</FormAndLineReferenceDesc>
        <ExplanationTxt>THE FOLLOWING DISCLOSURE IS RELATED TO THE COMBINED FINANCIAL STATEMENTS OF THE LOWELL OBSERVATORY, TRUST U/W OF PERCIVAL LOWELL, AND THE LOWELL OBSERVATORY FOUNDATION: THE OBSERVATORY, THE FOUNDATION, AND THE TRUST ARE EXEMPT FROM INCOME TAXES UNDER BOTH INTERNAL REVENUE CODE (IRC) SECTION 501(C)(3) AND ARIZONA INCOME TAX LAWS. THE OBSERVATORY IS CLASSIFIED AS OTHER THAN A PRIVATE FOUNDATION UNDER IRC SECTION 509(A)(1). THE FOUNDATION AND THE TRUST ARE EACH CLASSIFIED AS OTHER THAN A PRIVATE FOUNDATION UNDER IRC SECTION 509(A)(3) AS A SUPPORTING ORGANIZATION OF THE OBSERVATORY. INCOME FROM CERTAIN ACTIVITIES NOT DIRECTLY RELATED TO THE ORGANIZATION'S TAX-EXEMPT PURPOSE, HOWEVER, MAY BE SUBJECT TO TAXATION AS UNRELATED BUSINESS TAXABLE INCOME (UBTI). FROM TIME TO TIME, THE ORGANIZATION MAY BE SUBJECT TO PENALTIES AND INTEREST ASSESSED BY VARIOUS TAXING AUTHORITIES, WHICH ARE CLASSIFIED AS GENERAL AND ADMINISTRATIVE EXPENSES IF THEY OCCUR.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>SCHEDULE D, PART V, LINE 1C, COLUMN A</FormAndLineReferenceDesc>
        <ExplanationTxt>CALCULATION OF CURRENT YEAR INVESTMENT GAINS/(LOSSES): NET UNREALIZED LOSSES: -3,822,365 NET REALIZED GAINS: 159,236 INTEREST INCOME: 7,148 DIVIDEND INCOME: 376,146 MISCELLANEOUS INCOME: 1,252 NET INVESTMENT LOSS: -3,278,583</ExplanationTxt>
      </SupplementalInformationDetail>
    </IRS990ScheduleD>
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      <CompBsdNetEarnsRltdOrgsInd>0</CompBsdNetEarnsRltdOrgsInd>
      <AnyNonFixedPaymentsInd>0</AnyNonFixedPaymentsInd>
      <InitialContractExceptionInd>0</InitialContractExceptionInd>
      <RltdOrgOfficerTrstKeyEmplGrp>
        <PersonNm>LABRUZZO ANNE</PersonNm>
        <TitleTxt>CHIEF FINANCIAL OFFICER</TitleTxt>
        <BaseCompensationFilingOrgAmt>0</BaseCompensationFilingOrgAmt>
        <CompensationBasedOnRltdOrgsAmt>156024</CompensationBasedOnRltdOrgsAmt>
        <BonusFilingOrganizationAmount>0</BonusFilingOrganizationAmount>
        <BonusRelatedOrganizationsAmt>0</BonusRelatedOrganizationsAmt>
        <OtherCompensationFilingOrgAmt>0</OtherCompensationFilingOrgAmt>
        <OtherCompensationRltdOrgsAmt>0</OtherCompensationRltdOrgsAmt>
        <DeferredCompensationFlngOrgAmt>0</DeferredCompensationFlngOrgAmt>
        <DeferredCompRltdOrgsAmt>8200</DeferredCompRltdOrgsAmt>
        <NontaxableBenefitsFilingOrgAmt>0</NontaxableBenefitsFilingOrgAmt>
        <NontaxableBenefitsRltdOrgsAmt>13643</NontaxableBenefitsRltdOrgsAmt>
        <TotalCompensationFilingOrgAmt>0</TotalCompensationFilingOrgAmt>
        <TotalCompensationRltdOrgsAmt>177867</TotalCompensationRltdOrgsAmt>
        <CompReportPrior990FilingOrgAmt>0</CompReportPrior990FilingOrgAmt>
        <CompReportPrior990RltdOrgsAmt>0</CompReportPrior990RltdOrgsAmt>
      </RltdOrgOfficerTrstKeyEmplGrp>
    </IRS990ScheduleJ>
    <IRS990ScheduleM documentId="RetDoc1042900001">
      <SecuritiesPubliclyTradedGrp>
        <NonCashCheckboxInd>X</NonCashCheckboxInd>
        <ContributionCnt>2</ContributionCnt>
        <NoncashContributionsRptF990Amt>179253</NoncashContributionsRptF990Amt>
        <MethodOfDeterminingRevenuesTxt>TRANSACTION VALUE</MethodOfDeterminingRevenuesTxt>
      </SecuritiesPubliclyTradedGrp>
      <AnyPropertyThatMustBeHeldInd>0</AnyPropertyThatMustBeHeldInd>
      <ReviewProcessUnusualNCGiftsInd>0</ReviewProcessUnusualNCGiftsInd>
      <ThirdPartiesUsedInd>1</ThirdPartiesUsedInd>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>PART I, COLUMN (B):</FormAndLineReferenceDesc>
        <ExplanationTxt>THE AMOUNT IN COLUMN B REPRESENTS THE NUMBER OF INSTANCES THAT A DONATION OCCURRED.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>PART I, LINE 32B:</FormAndLineReferenceDesc>
        <ExplanationTxt>PUBLICLY TRADED SECURITIES ARE DEPOSITED INTO AN INVESTMENT ACCOUNT OWNED BY THE OBSERVATORY. THE SECURITIES ARE SOLD BY A BROKER SHORTLY AFTER.</ExplanationTxt>
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    </IRS990ScheduleM>
    <IRS990ScheduleO documentId="RetDoc1044400001">
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PART VI, SECTION A, LINE 7A</FormAndLineReferenceDesc>
        <ExplanationTxt>THE SOLE TRUSTEE IS RESPONSIBLE FOR NAMING THE SUCCESSOR TRUSTEE.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PART VI, SECTION A, LINE 8A</FormAndLineReferenceDesc>
        <ExplanationTxt>THE SOLE TRUSTEE WILL RECORD ACTIONS UNDERTAKEN FROM TIME TO TIME AS NEEDED.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PART VI, SECTION A, LINE 8B</FormAndLineReferenceDesc>
        <ExplanationTxt>THERE ARE NO COMMITTEES WITH AUTHORITY TO ACT ON BEHALF OF THE SOLE TRUSTEE/GOVERNING BODY.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PART VI, SECTION B, LINE 11B</FormAndLineReferenceDesc>
        <ExplanationTxt>THE FORM 990 DRAFT WILL BE FIRST REVIEWED BY THE CHIEF FINANCIAL OFFICER (CFO) FOR THE OBSERVATORY FOR ACCURACY. ONCE IT HAS BEEN DEEMED ACCURATE BY THE CFO, IT WILL BE FORWARDED TO THE SOLE TRUSTEE AND AUDIT COMMITTEE FOR THEIR REVIEW AND COMMENTS. AFTER ANY QUESTIONS AND COMMENTS HAVE BEEN ADDRESSED, THE 990 WILL BE APPROVED AND A FINAL COPY WILL BE SIGNED BY THE SOLE TRUSTEE.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PART VI, SECTION C, LINE 19</FormAndLineReferenceDesc>
        <ExplanationTxt>THE TRUST IS GOVERNED BY THE WILL OF PERCIVAL LOWELL AND EXISTS EXCLUSIVELY FOR THE BENEFIT OF LOWELL OBSERVATORY. WHEN REQUESTED, DOCUMENTS REGARDING THE TRUST ARE PROVIDED BY THE LOWELL OBSERVATORY BUSINESS OFFICE. THE 990 IS ALSO AVAILABLE ON CHARITY NAVIGATOR AND GUIDESTAR.</ExplanationTxt>
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          <BusinessNameLine1Txt>LOWELL OBSERVATORY</BusinessNameLine1Txt>
        </DisregardedEntityName>
        <USAddress>
          <AddressLine1Txt>1400 W MARS HILL ROAD</AddressLine1Txt>
          <CityNm>FLAGSTAFF</CityNm>
          <StateAbbreviationCd>AZ</StateAbbreviationCd>
          <ZIPCd>86001</ZIPCd>
        </USAddress>
        <EIN>860098918</EIN>
        <PrimaryActivitiesTxt>ASTRONOMICAL RESEARCH AND EDUCATION</PrimaryActivitiesTxt>
        <LegalDomicileStateCd>AZ</LegalDomicileStateCd>
        <ExemptCodeSectionTxt>501(C)(3)</ExemptCodeSectionTxt>
        <PublicCharityStatusTxt>LINE 7</PublicCharityStatusTxt>
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          <BusinessNameLine1Txt>TRUST UW OF PERCIVAL LOWELL</BusinessNameLine1Txt>
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        <ControlledOrganizationInd>1</ControlledOrganizationInd>
      </IdRelatedTaxExemptOrgGrp>
      <IdRelatedTaxExemptOrgGrp>
        <DisregardedEntityName>
          <BusinessNameLine1Txt>LOWELL OBSERVATORY FOUNDATION</BusinessNameLine1Txt>
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        <USAddress>
          <AddressLine1Txt>1400 W MARS HILL ROAD</AddressLine1Txt>
          <CityNm>FLAGSTAFF</CityNm>
          <StateAbbreviationCd>AZ</StateAbbreviationCd>
          <ZIPCd>86001</ZIPCd>
        </USAddress>
        <EIN>472052113</EIN>
        <PrimaryActivitiesTxt>FOUNDATION F/B/O LOWELL OBSERVATORY</PrimaryActivitiesTxt>
        <LegalDomicileStateCd>AZ</LegalDomicileStateCd>
        <ExemptCodeSectionTxt>501(C)(3)</ExemptCodeSectionTxt>
        <PublicCharityStatusTxt>LINE 12B, II</PublicCharityStatusTxt>
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      <GiftGrntCapContriFromOthOrgInd>1</GiftGrntCapContriFromOthOrgInd>
      <LoansOrGuaranteesToOtherOrgInd>1</LoansOrGuaranteesToOtherOrgInd>
      <LoansOrGuaranteesFromOthOrgInd>0</LoansOrGuaranteesFromOthOrgInd>
      <DivRelatedOrganizationInd>0</DivRelatedOrganizationInd>
      <AssetSaleToOtherOrgInd>0</AssetSaleToOtherOrgInd>
      <AssetPurchaseFromOtherOrgInd>0</AssetPurchaseFromOtherOrgInd>
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      <RentalOfFacilitiesToOthOrgInd>0</RentalOfFacilitiesToOthOrgInd>
      <RentalOfFcltsFromOthOrgInd>0</RentalOfFcltsFromOthOrgInd>
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      <ReimbursementPaidToOtherOrgInd>1</ReimbursementPaidToOtherOrgInd>
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          <BusinessNameLine1Txt>LOWELL OBSERVATORY</BusinessNameLine1Txt>
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        <MethodOfAmountDeterminationTxt>END OF YEAR BALANCE</MethodOfAmountDeterminationTxt>
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</Return>
