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Secondary Holder - Astrosystems Newtonian Secondary Mirror Holders

Astrosystems Newtonian Secondary Mirror Holders

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    Newtonian Secondary Holders

    AstroSystems is the largest supplier of secondary holders and spiders to the astronomical community.   There are no tools needed to adjust holders of 2.6" or larger in minor axis size; they come standard with thumbscrews. 

    Holders from 2.1" and smaller are supplied with a hex key that gives positive seating in the hex screw even in the dark. 

    All sizes feature our innovative four screw/two-axis adjustment that greatly simplifies collimation.   With a four screw adjustment, each screw is centered between the spider vanes, making collimation adjustments a snap. 

    Two nuts with nylon washers position the holder laterally and also allow easy adjustment of the rotation. 

    The secondary mirror is held securely yet safely against the front lip of the aluminum bezel with polyester batting.  Available in 19 sizes, ranging from 1.3" to 7.0".  Use the link below for dimensions, exact weight and sizing.

    1.3" to 1.5"  

    These have a #10 mounting stud and a 3/16" to 3/8" bushing to fit 3/8" spiders.  The smaller diameter mounting stud reduces the weight by 30%.  They utilize set screws for adjustment and the hex key is supplied.

    1.8" to 2.75"  

    These have a 1/4" mounting stud and a 1/4" to 3/8" bushing to fit both 1/4" and 3/8" spiders.  The smaller diameter mounting stud reduces the weight by 30%.  The 1.8" to 2.1" utilize set screws for adjustment and the proper size hex key is supplied.  The 2.5 to 2.75" have thumbscrews for easy, no tools collimation.

    3.0" to 3.5"

    These have a 3/8" mounting stud and have thumbscrews for easy, no tools collimation.  Shown at center in the above photo.  

    4.0" to 4.5"

    These larger holders have a proportionately thicker shell for proper support of  thicker, heavier secondaries and a 3/8" mounting stud.  They utilize 1" long thumbscrews for easy, no tools collimation.  Shown at right in the above photo.


    Dimensions and sizing of secondary holders

    Installation and Operation Instructions (pdf)


    Our Guarantee Our products are manufactured with the highest quality materials.  Years of testing, and high standards of production have produced the best possible products in the industry.  If a product has not  met with the customer's expectation, with prior approval, they can return the product directly to us for repair or replacement (our discretion).  We have no minimums on any of our products, so you can stock just what is comfortable for you and your store.  We fully guarantee our products for one year from the purchase date, longer on some products.  Our policy is to treat our dealers and their customers as we wish to be treated.  If an item does not live up to your expectation, please give us an opportunity to make it right.

    We work very hard to ensure that we offer the absolute best prices online.  If you find another online store that offers a lower price then us within six months of your purchase date please let us know and we will refund your original payment for the difference.  We want you to feel confident that you are getting the absolute best price for the product you are ordering.  If you find that our own website has a lower price for the same item you have ordered within six months of your purchase date will refund the difference as well.

    To request your partial refund simply e-mail us a link to the same product on our website, or on our competitors website within six months from the date of your order and we will process the credit accordingly.

    Our 100% Price Guarantee has some limitations:

    • You must purchase the item from our website before requesting your Price Match Guarantee
    • Promotions such as rebates and buy one, get one free offers are not eligible
    • The item must be in stock on the competitors website
    • The competitor must be an online store, they may not have a retail location
    • The website can not be a discounter or auction website (ie; eBay, overstock, etc..)
    • The competitor must be an Authorized Retailer of the product in question
    • The Price Match Guarantee includes the item price and the shipping charges, it excludes sales tax

    Customer Reviews

    Based on 2 reviews
    David Pfeiffer
    Great product fast shipping

    Item was perfect. Communication and attention to detail with this order were great.
    I’ll definitely buy from Skygaze in the future.

    Thomas Clarke
    Purchase Newtonian Secondary Mirror Holder

    Good product. Fast delivery.


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