SkyWatcher Cheshire Collimating Eyepiece

Further details

How to use a Cheshire Collimation Eyepiece
Remove the eyepiece or any other accessory from the focuser and rack the focuser all the way in towards the tube.

2.Insert the Collimation Eyepiece into the focuser far enough that the bottom edge of the barrel appears slightly larger than the outer edge of the secondary mirror when looking through the sight hole.

3.Rotate the eyepiece so that the cutout on the side of the barrel is towards an external light source. (If collimating at night, shine a flashlight through the cutout). Never point the cutout side of the eyepiece at or near the sun; serious and instant eye damage can result.

4.Look into the sight hole to determine if the secondary is positioned directly under the focuser tube. The center of the secondary mirror should be positioned directly under the intersection of the cross hairs. If the secondary is not centered in the cross hairs of the Collimation Eyepiece, it will need to be adjusted. This is usually done by rotating the threaded rod that holds the secondary holder. Additionally, the threaded rod can slide up and down through the spider for adjustments in the other axis. To adjust a stalk-type secondary holder, there is usually a center bolt that can be loosened to allow rotation of the secondary holder.

5.Next, you need to adjust the tilt of the secondary mirror so that the entire reflection of the primary mirror is visible in the secondary mirror. Use the three collimation screws located on the top of the secondary mirror holder to center the reflection of the primary mirror underneath the cross hairs of the Collimation Eyepiece.

6.Now that you can see the entire primary mirror reflected in the secondary mirror, you my notice that the reflection of the secondary mirror is not perfectly centered in the primary mirror (see figure 4). To correct this, you must adjust the primary mirror collimation screws located on the bottom of the primary mirror cell. Turn the collimation screws, one at a time, until the centerof the bright ring reflected in the secondary mirror is positioned in the center of the primary mirror. For added ease and accuracy, a small black dot can be placed in the center of the primary mirror and be used to align the primary. Simply adjust the mirror until the dot on the primary is centered in the middle of the bright ring. If the view seen through the focuser tube resembles that of figure 2, then your telescope is properly collimated and ready for observing. However, if the collimation is noticeably off, repeat steps 5 and 6 until aligned.

Delivery charge £5.95

Reviews

  Does the job  Nice tool to correctly adjust secondary mirror.  (08/04/2024) Michal -

  Easy to use and accurate  I'm new to reflectors and used this to collimate a 200mm. I thought the scope had good views but this tool showed the primary mirror to be slightly out. Easy to use and only took a few minutes to put the optics in perfect alignment. Amazingly quick and securely packaged delivery.  (23/03/2024) P - Kent

  Excellent addition  I didn’t think I needed this because I already had a laser collimator and cap but I also couldn’t quite work out why the view down the focusser never looked like the pictures. 5 mins with this sight tube and my secondary mirror is spot on again. I then used the laser collimator and cap. Perfect!  (07/02/2023) -

  Necessary   New to astronomy and reading about collimation was pretty daunting. However after buying this along with the Lazer collimator it's nothing to be worried about to be honest. Definitely a necessary tool. As others have mentioned super fast delivery from Harrison Telescopes  (13/11/2022) Steve - Snowdonia

  Easy enough   Easy enough to use and well it's just pretty much one of them items that are good to have and you only have to buy once . Recommended .  (19/10/2022) Sean - Guildford

  Easy to use collimator  Very nice piece of equipment at a very reasonable price. Website was easy to use and item was delivered quickly. However the task of using it would have been so much easier if it had come with operating instructions!  (20/09/2022) Christine - Wilstead

  Very useful for a newbie  Collimation was a totally new concept to me as a newbie to astronomy but this piece of kit made it so easy to adjust my mirrors. Nice and simple to purchase and not too expensive. Delivered really quickly. Very happy on all sides of the coin.  (02/05/2022) viragopaul - Hertfordshire

  Useful tool  It arrived sooner then expected, is well made and is more accurate than just a collimation cap alone.  (01/02/2021) Dan - Leyburn, N. Yorks.

  Collimating made easy  Bought thus to collimate my Celestron 130q as it was showing blurry images. Arrived promptly as expected and is a well made piece of equipment. It was easy to set up and use and within a few minutes my telescope was fully collimator. Excellent product and valuable tool for collimating.  (31/01/2021) Alan Darbyshire - Wigan

  Top quality quick service  I ordered this late afternoon to accurately collamate my new telescope and it came through the letterbox the next day. Quick service and value for money. Thank you  (28/06/2020) Dan -

  great  Super service delivered this great piece of kit quickly. No problems using it.  (28/06/2020) david uprichard - sussex

  Arrived on time as described  The cheshire collimator looked a quality piece of equipment and worked perfectly. The only issue i had was the lack of intructions on how to use it. I would have given 5 stars if you had included instructions.   (13/01/2020) mark - rutland
Our Reply: Thank you - a very good point we will publish some instructions

  good service from harrison telescopes ltd  I was very pleased with the service I received when I placed an on line order for a skywatcher cheshire collimating eyepiece from harrison telescopes it came by GPO post and arrived within 4 days. As for the collimating eye piece it is well made , have not used it so I cant rate it   (11/10/2019) gerry - bath

  Useful even if you have a laser collmator  I already own a laser collimator, and although it is great for alignment of the secondary mirror and general collimation, I find that with the cheshire I get a little more fine control over the process. I recommend the two in combination.   (09/08/2019) -

  Just the trick!  This has solved a few setting up problems and is great value and price on this site.   (17/05/2019) -

  Good quality tool  Collimated my 130mm Newtonian really well (after centre spotting the primary mirror)   (04/07/2018) PS - Maldon

  Skywatcher Cheshire  I needed 5 items, including this Cheshire. I'd not used Harrisons before, but they had everything I needed in stock and prices were good, so I placed a couple of orders. Got an email confirming orders sent same day, and everything arrived well packaged the day after order. Excellent service.   (18/03/2018) paul - UK

  Well made tool  I bough this with my 200p explorer, the quality is very good and it serves the purpose. For me i didn't get on with it though, with my glasses on and a 1000mm telescope i struggled a but to use it to it's full. That's not the collimators fault though so 4 stars. I personally prefer the laser   (09/02/2018) Martin - Yorkshire

  Perfect collimation tool  Solid and easy to use piece of equipment. Makes lining up the mirrors very straight forward in no time. Can’t recommend enough!   (05/01/2018) Forbes - Edinburgh

  Good item easy to use. Excellent customer service  Bought this at the same time as a skyliner 200p. It was on back order and sent with in the week as promised. All queries were answered promptly and courteously. Quality item backed up with quality service.   (04/11/2017) Rob Armstrong - Nottingham

  skywatcher collimating eyepiece indispencable   with the skywatcher collimating eyepiece I collimated my skywatcher EX150 in under 2mins better than the eyepiece cap with a pin hole in it I didn't think I would need a collimating tool until I bought this   (28/05/2017) j gregory - newcastle