JSP 1.25" EasyTester II Autocollimator for Dobsonian and Newtonian Telescopes
Availability: Item has been discontinued by the manufacturer
Contiguous US Customers:
All items we sell ship for free within the Contiguous US. Shipping will be via the cheapest shipping method which will vary depending on the items in your order. During checkout, you may also be shown other optional faster shipping choices.
US Customers in Hawaii and Alaska:
Free shipping applies to almost all products. A few large telescopes and mounts are excluded from this free shipping offer. For these items, please contact us to obtain a shipping quote before you check out using the online shopping cart.
International Customers:
Free shipping does not apply to international orders. During check-out, you will be presented with several shipping choices and costs. However, the export of some items may be restricted outside the US due to size or manufacturer restrictions.
The EASYTESTER II (by Jack Schmidling Productions) is an eyepiece-like device that allows the owner or user of any Newtonian / Dobsonian reflector telescope to quickly determine the current condition of the collimation and assist in correcting it if necessary.
Anyone who has ever purchased or built a telescope has experienced that uncertain feeling of not knowing whether those un-textbook-like images are the fault of the optics, faulty adjustments or just seeing conditions.
The EASYTESTER II is technically known as an autocollimator. It is "auto" in the sense that once perfect collimation is achieved, the reflected image goes dark and leaves no doubt. It consists of a small perforated mirror mounted in an eyepiece.
Using the JSP EasyTester II auto collimator
Just insert the EasyTester II into your telescope's 1.25" focuser. The drawing in the second photo above represents the view when looking through the autocollimator. The outer circle is the aperture at the end of the scope. The dot in the center of the auto collimator mirror is the reflection of the perforation at the eye end. The spot to the left represents the dot on the center of the primary in a slightly out of collimation system.
Adjustments to the secondary and primary mirror are made until the two spots line up or all of the reflected circles are concentric. When the precise point is reached, the AC mirror darkens and alignment is perfect.
If the primary mirror in your telescope does not have a central spot, it can be added with a marking pen. As it is blocked by the secondary, it has no effect on the image. The spot is not necessary for autocollimation but it greatly simplifies the rough alignment.
| Product Banner Type | discontinued |
|---|---|
| Free Shipping Graphic | Free US Shipping |
| Hide Found a better Shipped Price on Frontend? | No |
The EASYTESTER II (by Jack Schmidling Productions) is an eyepiece-like device that allows the owner or user of any Newtonian / Dobsonian reflector telescope to quickly determine the current condition of the collimation and assist in correcting it if necessary.
Anyone who has ever purchased or built a telescope has experienced that uncertain feeling of not knowing whether those un-textbook-like images are the fault of the optics, faulty adjustments or just seeing conditions.
The EASYTESTER II is technically known as an autocollimator. It is "auto" in the sense that once perfect collimation is achieved, the reflected image goes dark and leaves no doubt. It consists of a small perforated mirror mounted in an eyepiece.
Using the JSP EasyTester II auto collimator
Just insert the EasyTester II into your telescope's 1.25" focuser. The drawing in the second photo above represents the view when looking through the autocollimator. The outer circle is the aperture at the end of the scope. The dot in the center of the auto collimator mirror is the reflection of the perforation at the eye end. The spot to the left represents the dot on the center of the primary in a slightly out of collimation system.
Adjustments to the secondary and primary mirror are made until the two spots line up or all of the reflected circles are concentric. When the precise point is reached, the AC mirror darkens and alignment is perfect.
If the primary mirror in your telescope does not have a central spot, it can be added with a marking pen. As it is blocked by the secondary, it has no effect on the image. The spot is not necessary for autocollimation but it greatly simplifies the rough alignment.
| Product Banner Type | discontinued |
|---|---|
| Free Shipping Graphic | Free US Shipping |
| Hide Found a better Shipped Price on Frontend? | No |