Explore Scientific HR Variable Coma Corrector 2 inch

I have a 16" f/4.5 and a couple f/5 telescopes. For the longest time, I thought I never needed a coma corrector and felt that I could live without the correction. With my wide field eyepieces, I always had coma on the outer 30% of the field, if not more. I thought it was acceptable until I tried the Explore Scientific HR Coma Corrector.This coma corrector is rated for scopes down to F/3 (very fast scopes!) and it does an excellent job correcting coma. This will produce the same kind of "WOW" factor as going up in aperture-- the difference between corrected and uncorrected is just that big of an improvement. Stars became sharp pinpoints across the field and lost some of their bloat. The separation of double stars became much clearer and large star clusters took are a joy to observe. My observations vastly improved by adding this to my eyepiece kit.This will add some heft to your focuser, but it is worth it. The helical top makes it easy to adjust focus between eyepieces and it operates similarly to the more expensive Televue Paracorr with tunable top, but with finer focusing precision. This eyepiece is a joy to use with my Explore Scientific 100 degree eyepieces.

Great sturdy product. I compared the features to the GSO and Tele Vue Paracorr II models, and decided to give this one a shot. I did a little research beforehand and determined that I would need more in-focus to use this HRCC, so I bought 3 M6-1.0X60mm bolts to move my mirror up the tube of my Z12 Dob.I am now able to get all of my eyepieces to come to focus with and without the HRCC, but there is really no need to remove it since the HRCC yields the best DSO and planetary views I've ever seen with this scope. I can let Jupiter track from edge to edge of my 100° eyepieces and the image stays sharp. Coma is no longer noticeable once focus is achieved. I love the helical focusing, but it is easier with parfocal eyepieces. This is an accessory that I didn't think I needed at F/4.9, but I am REALLY enjoying the cleaner views.This product is highly recommended if you can accommodate its in-focus requirements and added weight.-Dan

One of the drawbacks of Newtonian telescopes with "faster" focal ratios is coma distortion. I have an f/4.5 Newtonian and quickly learned this fact when observing stars rather than planets and nebulae. Now, while most people recommend the Tele-Vue Paracorr coma corrector, I found that the Explore Scientific coma corrector appears to work perfectly well with the Explore Scientific eyepieces I already use regularly. Respectable optics as a more modest price than the higher end Tele-Vue optics presents an added bonus.

I would rate this excellent, and my Baader MPCC as fair. I'll take this item anytime, and you have the flexibility to use visually as well as photographically. Highly recommended.