Coma corrector

[Connor brad]

Hi I have a 8 inch f5 skywatcher explorer with a dual speed focuser I'm looking to buy a coma corrector but not the paracorr as that's way past me budget there's no way I'm paying that much money what's the second best coma corrector after the paracorr  that is a bit cheaper? although I got a 27mm panoptics, 18mm celestron xcel and 12mm bst starguider since I have a televue eyepiece is it only the paracorr that works on televue eyepieces or can I use any coma corrector with it? 

[Louis D]

I use the GSO/Revelation coma corrector with a 25mm spacer between the optics section and the eyepiece holder.  As long as all your eyepiece focus within about 5mm of the eyepiece shoulder, I've not found a need to tune the distance for each eyepiece.  For me, eliminating 95% of the coma is good enough.  It does require about 11mm of in focus, so it is similar to the Paracorr II.

The ES HR corrector requires about 35mm of in focus, so not all scopes are able to achieve focus with it.  Most reviews of it are positive aside from the very find threads to tune correction.

[Louis D]

16 minutes ago, Connor brad said:

although I got a 27mm panoptics, 18mm celestron xcel and 12mm bst starguider since I have a televue eyepiece is it only the paracorr that works on televue eyepieces or can I use any coma corrector with it? 

Yes, you can use any coma corrector with any telescope and any eyepiece.  However, if you had an f/4 or faster Dob, I would definitely recommend the Paracorr II.

[Connor brad]

54 minutes ago, Louis D said:

I use the GSO/Revelation coma corrector with a 25mm spacer between the optics section and the eyepiece holder.  As long as all your eyepiece focus within about 5mm of the eyepiece shoulder, I've not found a need to tune the distance for each eyepiece.  For me, eliminating 95% of the coma is good enough.  It does require about 11mm of in focus, so it is similar to the Paracorr II.

The ES HR corrector requires about 35mm of in focus, so not all scopes are able to achieve focus with it.  Most reviews of it are positive aside from the very find threads to tune correction.

Should the explore scientific coma corrector work in my scope? 

[Louis D]

2 hours ago, Connor brad said:

Should the explore scientific coma corrector work in my scope? 

When you have reached focus with your most inward focusing eyepiece, measure the distance the focuser tube has left to travel inward.  You'll need ~35mm of inward travel to reach focus with the ES as I said above.  My Dob's low profile focuser has only about 20mm of inward focuser travel left with most of my eyepieces, so it wouldn't work for me.

I'm assuming that since your scope claims to be optimized for photography, it has at least 55mm of back focus available for T-ring attachment of DSLRs:

                Also the tube length has been slightly shortened to optimize performance for prime-focus photography