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                                                                    EXHIBIT 10.5

1998 NSO-1                                                     50,000 Shares

                               GALILEO CORPORATION
                             1991 Stock Option Plan
                      Nonstatutory Stock Option Certificate


         Galileo Corporation, Inc. (the "Company"), a Delaware corporation,
hereby grants to the person named below an option (the "Option") to purchase
shares of Common Stock, $.01 par value of the Company (the "Common Stock") under
and subject to the Company's 1991 Stock Option Plan (the "Plan") exercisable on
the following terms and conditions and those attached to this certificate:

Name of Optionholder:                                              W. Kip Speyer
Address:                                                     10361 Parkstone Way
                                                      Boca Raton, Florida  33498


Number of Shares:                                                         50,000
Option Price:                                                             $3.875
Date of Grant:                                                 December 31, 1998

Exercisability Schedule:On or after the Date of Grant as to 20,000 shares 
                        after September 30, 1999 as to 20,000 additional shares,
                        after September 30, 2000 as to 10,000 additional shares.

Expiration Date:                                               December 31, 2008

         Notwithstanding the foregoing, in the event of a Change in Control of
the Company (as defined in Section 3 of the attached terms and conditions), this
Option shall become exercisable as to all shares without regard to any deferred
exercise period.

         This Option shall not be treated as an Incentive Stock Option under
section 422 of the Internal Revenue Code of 1986, as amended (the "Code").

         By acceptance of this Option, the Optionholder agrees to the terms and
conditions hereof.


                                                     GALILEO CORPORATION


                                                     By: /s/ Josef W. Rokus 
                                                         ------------------
                                                         Vice President


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                            [Back of NSO Certificate]

                   GALILEO CORPORATION 1991 STOCK OPTION PLAN


                 NONSTATUTORY STOCK OPTION TERMS AND CONDITIONS


         1. PLAN INCORPORATED BY REFERENCE. This Option is issued under and
subject to the terms of the Plan and may be amended as provided in the Plan.
Capitalized terms used and not otherwise defined in this certificate have the
meanings given to them in the Plan. This certificate does not set forth all of
the terms and conditions of the Plan, which are incorporated herein by
reference. The Committee administers the Plan and its determinations regarding
the operation of the Plan are final and binding.
Copies of the Plan may be obtained upon written request without charge from the
Company.


         2. OPTION PRICE. The price to be paid for each share of Common Stock
issued upon exercise of the whole or any part of this Option is the Option Price
set forth on the first page of this certificate.


         3. EXERCISABILITY SCHEDULE. This Option may be exercised at any time
and from time to time for the number of shares and in accordance with the
exercisability schedule set forth on the first page of this certificate;
provided, however, that in the event of a Change in Control of the Company, this
Option shall become exercisable as to all shares without regard to any deferred
exercise period. For this purpose, "Change in Control" means a change in control
of the Company of a nature that would be required to be reported in response to
Item 6(e) of Schedule 14A of Regulation 14A under the Securities Exchange Act of
1934, as amended (the "Exchange Act"), whether or not the Company is in fact
required to comply therewith; provided that without limitation, a Change in
Control shall be deemed to have occurred if:


         (a) any "person" (as such term is used in Sections 13(d) and 14(d) of
the Exchange Act), other than the Company, any trustee or other fiduciary
holding securities under an employee benefit plan of the Company or a
corporation owned directly or indirectly by the shareholders of the Company in
substantially the same proportions as their ownership of stock of the Company,
is or becomes the "beneficial owner" (as defined in Rule 13d-3 under the
Exchange Act) directly or indirectly of securities of the Company representing
40% or more of the combined voting power of the Company's then outstanding
securities;


         (b) during any period of 24 consecutive months (not including any
period prior to the date of this Option), individuals who at the beginning of
such period constitute the Board of Directors of the Company and any new
director (other than a director designated by a person who has entered into an
agreement with the Company to effect a transaction described in subsections (a),
(c) or (d) of this Section 3) whose election by the Board of Directors of the
Company or nomination for election by the shareholders of the Company was
approved by a vote of at least two-thirds of the directors then still in office
who either were directors at the beginning of such period or whose election or
nomination for election was previously so approved cease for any reason to
constitute a majority thereof;


         (c) the shareholders of the Company approve a merger or consolidation
of the Company with any other corporation other than (i) a merger or
consolidation which would result in the voting securities of the Company
outstanding immediately prior thereto continuing to represent (either by
remaining outstanding or by being converted into voting securities of the
surviving entity) at least 50% of the combined voting securities of the Company
or such surviving entity outstanding immediately after such merger or
consolidation or (ii) a merger or consolidation effected to implement a
recapitalization of the Company (or similar transaction) in which no "person"
(as defined above) acquires 40% or more of the combined voting power of the
Company's then outstanding securities; or


         (d) the shareholders of the Company approve a plan of complete
liquidation of the Company or an agreement for the sale or disposition by the
Company of all or substantially all of the Company's assets.


         This Option may be exercised only for the purchase of whole shares and
may not be exercised as to any shares after the Expiration Date.


         4. METHOD OF EXERCISE. To exercise this Option, the Optionholder must
deliver written notice of exercise to the Company specifying the number of
shares with respect to which the Option is being exercised accompanied by
payment of the Option Price for such shares in cash, by certified check or in
such other form, including shares of Common Stock valued at their Fair Market
Value on the date of delivery, as the Committee may approve. Promptly following
such notice, the Company will deliver to the Optionholder a certificate
representing the number of shares for which the Option is being exercised.


         5. RIGHTS AS A STOCKHOLDER OR EMPLOYEE. The Optionholder has no rights
in shares as to which the Option has not been exercised and payment made as
provided above. The Optionholder has no rights to continued employment by the
Company or its Affiliates by virtue of the grant of this Option.


         6. RECAPITALIZATION, MERGERS, ETC. As provided in the Plan, in the
event of corporate transactions affecting the Company's outstanding Common
Stock, the Committee will equitably adjust the number and kind of shares subject
to this Option and the exercise price hereunder or make provision for a cash
payment. If such transaction involves a consolidation or merger of the Company
with another entity, the sale or exchange of all or substantially all of the
assets of the Company or a reorganization or liquidation of the Company, then in
lieu of the foregoing, the Committee may upon written notice to the Optionholder
provide that this Option shall terminate on a date not less than 20 days after
the date of such notice unless theretofore exercised. In connection with such
notice, the Committee may in its discretion accelerate or waive any deferred
exercise period.


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         7. OPTION NOT TRANSFERABLE. Except as otherwise permitted by the
Committee, this Option is not transferable by the Optionholder otherwise than by
will or the laws of descent and distribution, and is exercisable during the
Optionholder's lifetime only by the Optionholder. The naming of a Designated
Beneficiary does not constitute a transfer.


         8. EXERCISE OF OPTION AFTER TERMINATION OF EMPLOYMENT. If the
Optionholder's status as an employee of the Company or an Affiliate is
terminated for any reason other than by disability or death, the Optionholder
may exercise the rights which were available to the Optionholder at the time of
such termination only within three months from the date of termination. If such
status is terminated as a result of disability, such rights may be exercised
only within twelve months from the date of termination. Upon the death of the
Optionholder, his or her Designated Beneficiary shall in lieu of any other
rights hereunder have the right, at any time within twelve months after the date
of death, to exercise in whole or in part any rights that were available to the
Optionholder at the time of death. Notwithstanding the foregoing, no rights
under this Option may be exercised after the Expiration Date.


         9. COMPLIANCE WITH SECURITIES LAWS. As a condition to the
Optionholder's right to purchase shares of Common Stock hereunder, the Company
may, in its discretion, require that (a) the shares of Common Stock reserved for
issue upon the exercise of this Option shall have been duly listed, upon
official notice of issuance, upon any national securities exchange or automated
quotation system on which the Company's Common Stock may then be listed or
quoted, (b) either (i) a registration statement under the Securities Act of 1933
with respect to the shares shall be in effect, or (ii) in the opinion of counsel
for the Company, the proposed purchase shall be exempt from registration under
that Act and the Optionholder shall have made such undertakings and agreements
with the Company as the Company may reasonably require, and (c) such other
actions, if any, as counsel for the Company shall consider necessary to comply
with any law applicable to the issue of such shares by the Company shall have
been taken by the Company or the Optionholder, or both. The certificates
representing the shares purchased under this Option may contain such legends as
counsel for the Company considers necessary to comply with any applicable law.


         10. PAYMENT OF TAXES. The Optionholder must pay to the Company, or make
provision satisfactory to the Company for payment of, any taxes required by law
to be withheld with respect to the exercise of this Option. The Committee may,
in its discretion, require any other Federal or state taxes imposed on the sale
of the shares to be paid by the Optionholder. In the Committee's discretion,
such tax obligations may be paid in whole or in part in shares of Common Stock,
including shares retained from the exercise of this Option, valued at their Fair
Market Value on the date of delivery. The Company and its Affiliates may, to the
extent permitted by law, deduct any such tax obligations from any payment of any
kind otherwise due to the Optionholder.


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