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                                                                      EXHIBIT 10



                               GALILEO CORPORATION

                             1991 STOCK OPTION PLAN

SECTION 1.   Purpose

     The purpose of the Galileo Corporation 1991 Stock Option Plan (the "Plan")
is to attract and retain key employees and consultants, to provide an incentive
for them to assist the Company to achieve long-range performance goals and to
enable them to participate in the long-term growth of the Company.

SECTION 2.   Definitions

     "Affiliate" means any business entity in which the company owns directly or
indirectly 50% or more of the total combined voting power or has a significant
financial interest as determined by the Committee.

     "Award" means any Option or Stock Appreciation Right awarded under the
Plan.

     "Company" means Galileo Corporation.

     "Board" means the Board of Directors of the Company.

     "Code" means Internal Revenue Code of 1986, as amended from time to time.

     "Committee" means a committee of not fewer than three members of the Board
appointed by the Board to administer the Plan, each of whom is a "disinterested
person" as defined in Rule 16b-3 under Section 16(b).

     "Common Stock" or "Stock" means the Common Stock of the Company.

     "Designated Beneficiary" means the beneficiary designated by a Participant,
in a manner determined by the Committee, to receive amounts due or exercise
rights of the Participant in the event of the Participant's death. In the
absence of an effective designation by a Participant, Designated Beneficiary
shall mean the Participant's estate.

     "Fair Market Value" means, with respect to Common Stock or any other
property, the fair market value of such property as determined by the Committee
in good faith or in the manner established by the Committee from time to time.

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     "Incentive Stock Option" means an option to purchase shares of Common Stock
awarded to a Participant under Section 6 that is intended to meet the
requirements of Section 422 of the Code or any successor provision.

     "Non-qualified Stock Option" means an option to purchase shares of Common
Stock under Section 6 that is not intended to be an Incentive Stock Option.

     "Option" means an Incentive Stock Option or a Non-qualified Stock Option.

     "Participant" means a person selected by the Committee to receive an Award
under the Plan.

     "Reporting Person" means a person subject to Section 16 of the Securities
Exchange Act of 1934 or any successor provision.

     "Section 16(b)" means Section 16(b) of the Securities Exchange Act of 1934,
or any successor provision.

     "Stock Appreciation Right" or "SAR" means a right to receive any excess in
value of shares of Common Stock over the exercise price awarded to a Participant
under Section 7.

SECTION 3.   Administration

     The Plan shall be administered by the Committee. The Committee shall have
authority to adopt, alter and repeal such administrative rules, guidelines and
practices governing the operation of the Plan as it shall from time to time
consider advisable, and to interpret the provisions of the Plan. The Committee's
decisions shall be final and binding. To the extent permitted by applicable law,
the Committee may delegate to one or more executive officers of the Company the
power to make Awards to Participants who are not Reporting Persons and all
determinations under the Plan with respect thereto, provided that the Committee
shall fix the maximum amount of such Awards for the group and a maximum for any
one Participant.

     Subject to any disinterested administration requirements for exemptive
relief under Section 16(b) with respect to Awards to Reporting Persons, the
Board may also make Awards and exercise administrative authority under the Plan
to the same extent as the Committee.

SECTION 4.   Eligibility

     All employees, and in the case of Awards other than Incentive Stock
Options, consultants of the Company or any Affiliate capable of contributing
significantly to the 


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successful performance of the Company, other than any person who has irrevocably
elected not to be eligible, are eligible to be Participants in the Plan.

SECTION 5.   Stock Available for Awards

     (a) Subject to adjustment under subsection (b), Awards may be made under
the Plan for up to 550,000 shares of Common Stock. If any Award in respect to
shares of Common Stock expires or is terminated unexercised or is forfeited for
any reason, the shares subject to such Award, to the extent of such expiration,
termination or forfeiture, shall again be available for award under the Plan,
subject, however, in the case of Incentive Stock Options, to any limitation
required under the Code. Shares issued under the Plan may consist in whole or in
part of authorized but unissued shares or treasury shares.

     (b) In the event that the Committee determines that any stock dividend,
extraordinary cash dividend, creation of a class of equity securities,
recapitalization, reorganization, merger, consolidation, split-up, spin-off,
combination, exchange of shares, warrants or rights offering to purchase Common
Stock at a price substantially below market value, or other similar transaction
affects the Common Stock such that an adjustment is required in order to
preserve the benefits or potential benefits intended to be made available under
the Plan, then the Committee, subject, in the case of Incentive Stock Options,
to any limitation required under the Code, shall equitably adjust any or all of
(i) the number and kind of shares in respect of which Awards may be made under
the Plan, (ii) the number and kind of shares subject to outstanding Awards, and
(iii) the exercise price with respect to any of the foregoing, and if considered
appropriate, the Committee may make provision for a cash payment with respect to
an outstanding Award, provided that the number of shares subject to any Award
shall always be a whole number.

     (c) The maximum number of shares of Common Stock subject to Options and
Stock Appreciation Rights that may be granted to any Participant in the
aggregate in any fiscal year of the Company shall not exceed 100,000, subject to
adjustment under subsection (b).

SECTION 6.   Stock Options

     (a) Subject to the provision of the Plan, the Committee may award Incentive
Stock Options and Non-qualified Stock Options and determine the number of shares
to be covered by each Option, the option price therefor and the conditions and
limitations applicable to the exercise of the Option. The terms and conditions
of Incentive Stock Options shall be subject to and comply with Section 422 of
the Code, or any successor provision, and any regulations thereunder. 

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     (b) The Committee shall establish the option price at the time each Option
is awarded, which price shall be not less than 100% of the Fair Market Value of
the Common Stock on the date of award.

     (c) Each Option shall be exercisable at such times and subject to such
terms and conditions as the Committee may specify in the applicable Award or
thereafter. The Committee may impose such conditions with respect to the
exercise of Options including conditions relating to applicable federal or state
securities laws, as it considers necessary or advisable.

     (d) No shares shall be delivered pursuant to any exercise of an Option
until payment in full of the option price therefor is received by the Company.
Such payment may be in whole or part in cash or, to the extent permitted by the
Committee at or after the award of an Option upon the delivery of shares of
Common Stock owned by the optionee valued at their Fair Market Value on the date
of delivery, or such other lawful consideration as the Committee may determine.

     (e) The Committee may provide for the automatic award of an Option upon the
delivery of shares to the Company in payment of an Option for up to the number
of shares so delivered.

SECTION 7.   Stock Appreciation Rights

     (a) Subject to the provisions of the Plan, the Committee may award SARs in
tandem with an Option (at or after the award of the Option), or alone and
unrelated to an Option. SARs in tandem with an Option shall terminate to the
extent that the related Option is exercised, and the related Option shall
terminate to the extent that the tandem SARs are exercised. SARs shall have an
exercise price of not less than 100% of the Fair Market Value of the Common
Stock on the date of award, or in the case of SARs in tandem with Options, the
exercise price of the related Option.

     (b) An SAR related to an Option that can only be exercised during limited
periods following a change in control of the Company may entitle the Participant
to receive an amount based upon the highest price paid or offered for Common
Stock in any transaction relating to the change in control or paid during the
thirty-day period immediately preceding the occurrence of the change control in
any transaction reported in the stock market in which the Common Stock is
normally traded.

SECTION 8.  General Provisions Applicable to Awards

     (a) Reporting Person Limitations. Notwithstanding any other provision of
the Plan, to the extent required to qualify for the exemption provided by Rule
16b-3 under Section 16(b), any Option or SAR issued under the Plan to a
Reporting Person shall not be 


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transferable other than by will or the laws of descent and distribution and
shall be exercisable during the Participant's lifetime only by the Participant
or the Participant's guardian or legal representative.

     (b) Documentation. Each Award under the Plan shall be evidenced by a
writing delivered to the Participant specifying the terms and conditions thereof
and containing such other terms and conditions not inconsistent with the
provisions of the Plan as the Committee considers necessary or advisable to
achieve the purposes of the Plan or comply with applicable tax and regulatory
laws and accounting principles.

     (c) Committee Discretion. Each type of Award may be made alone or in
addition to or in relation to any other type of Award. The terms of each type of
Award need not be identical, and the Committee need not treat Participants
uniformly. Except as otherwise provided by the Plan or a particular Award, any
determination with respect to an Award may be made by the Committee at the time
of Award or at any time thereafter.

     (d) Settlement. The Committee shall determine whether Awards are settled in
whole or in part in cash, Common Stock, other securities of the Company, Awards
or other property. The Committee may permit a Participant to defer all or any
portion of a payment under the Plan.

     (e) Cash Awards. In the discretion of the Committee, any Award under the
Plan may provide cash payments to the Participant in lieu of or in addition to
an Award.

     (f) Termination of Employment. The Committee shall determine the effect on
an Award of the disability, death, retirement or other termination of employment
of a Participant and the extent to which, and the period during which, the
Participant's legal representative, guardian, or Designated Beneficiary may
receive payment of an Award or exercise rights thereunder.

     (g) Change in Control. In order to preserve a Participant's right under an
Award in the event of a change in control of the Company, the Committee in its
discretion may, at the time an Award is made or at any time thereafter, take one
or more of the following actions: (i) provide for the acceleration of any time
period relating to the exercise or realization of the Award, (ii) provide for
the purchase of the Award upon the Participant's request for an amount of cash
or other property that could have been received upon the exercise or realization
of the Award had the Award been currently exercisable or payable, (iii) adjust
the terms of the Award in a manner determined by the Committee to reflect the
change in control, (iv) cause the Award to be assumed, or new rights substituted
therefor, by another entity, or (v) make such other provision as the Committee
may consider equitable and in the best interests of the Company.


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     (h) Withholding. The Participant shall pay to the Company, or make
provision satisfactory to the Committee for payment of, any taxes required by
law to be withheld in respect of Awards under the Plan no later than the date of
the event creating the tax liability. 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 Award creating the tax obligation, 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 participant.

     (i) Amendment of Award. The Committee may amend, modify or terminate any
outstanding Award, including substituting therefor another Award of the same or
a different type, changing the date of exercise or realization and converting an
Incentive Stock Option to a Non-qualified Stock Option, provided that the
Participant's consent to such action shall be required unless the Committee
determines that the action, taking into account any related action, would not
materially and adversely affect the Participant.

SECTION 9.   Miscellaneous.

     (a) No Right To Employment. No persons shall have any claim or right to be
granted an Award, and the grant of an Award shall not be construed as giving a
Participant the right to continued employment. The Company expressly reserves
the right at any time to dismiss a Participant free from any liability or claim
under the Plan, except as expressly provided in the applicable Award.

     (b) No Rights As Shareholder. Subject to the provisions of the applicable
Award, no Participant or Designated Beneficiary shall have any rights as a
shareholder with respect to any shares of Common Stock to be distributed or
acquired under the Plan until he or she becomes the holder thereof.

     (c) Effective Date. Subject to the approval of the shareholders of the
Company, the Plan shall be effective on October 23, 1991. Awards may be made
before, but expressly subject to, such approval.

     (d) Amendment of Plan. The Board may amend, suspend or terminate the Plan
or any portion thereof at any time, provided that no amendment shall be made
without shareholder approval if such approval is necessary to comply with any
applicable tax or regulatory requirement, including any requirement for
exemptive relief under Section 16(b).

     (e) Governing Law. The provisions of the Plan shall be governed and
interpreted in accordance with the laws of Massachusetts.



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