TS/Skywatcher Coma corrector questions

[PeterWar]

I've been thinking of buying a coma corrector to use my widefield eyepieces in my f 4.6 scope.

 

The original idea was to buy a Paracorr type 2, that could also be used on my future f 3 - f 3.5 scope, I'm now leaning towards alternatives due to the following reasons:

 

-I don't want to loose any FOV due to the 1.15X barlow effects of the Paracorr

-I can't focus some of my eyepieces in my current scope due to lack of OUT focus, so I want to minimize any barlow effect so that my CC effectively adds some OUT focus

-I think I will lean to a feather touch focuser with SIPS installed in my future f 3 scope so no need to buy a paracorr now.

 

 

Due to this reasons, I'm leaning towards the TS/Skywatcher coma correctors. I also like that they act as a 0.9X focal reducers, so I presume I would get a bigger TFOV, that would be very nice to have.

 

Does anyone have experience with this type of coma corrector? do they screw in eyepieces like the Baader MPCC? or can they be easily used on multiple eyepieces in an easy way?

 

Many thanks in advance!

[cs1cjc]

I can recommend the GSO/Altair Astro/ AstroTech model for such a scope.  It does however act as a 1.1X barlow and takes a little setting up.

[rl]

You don't say what eyepieces you are using but I'd beware of trading one set of aberrations for another if you speed the system up with the 0.9* multiplication factor...you will lose coma in the primary image but may well introduce extra off-axis problems in the eyepiece. f/4 is a harsh test that only televue and a few others really pass...

RL

[PeterWar]

Than

You don't say what eyepieces you are using but I'd beware of trading one set of aberrations for another if you speed the system up with the 0.9* multiplication factor...you will lose coma in the primary image but may well introduce extra off-axis problems in the eyepiece. f/4 is a harsh test that only televue and a few others really pass...

RL

I think I have the eyepiece front well covered with the following eyepieces:

 

3mm TeleVue Radian

4mm Fujiyama HD ortho

5mm Pentax XW

6mm TeleVue Delos

11mm ES 82º

17mm Nikon NAV HW with EiC 14

31mm Nagler

31mm Nagler Type 5

[PeterWar]

bump

[gooseholla]

You have a high quality set of eyepiece so I don't think the coma corrector will add any problems off axis. I've not had any experience of them or any coma corrector but they seem easy enough to use and setup. I believe it comes in two parts, a coma corrector and tube. The tube has a standard filter thread for the coma corrector to screw into allowing multiple eyepieces to slip in and out like a normal focuser barrel. Not sure this version screws into the eyepieces itself?

The tube will add a bit of height to the eyepiece holder on the focuser so it may well allow some eyepieces to focus.

0.9x focal reducer will change the focal length of the scope according to the description. So multiply the focal ratio by 0.9 and you'll see you'll actually get an increase in magnification it seems? e.g. f/5 becomes f/4.5, etc.

For £100 it may be worth a punt - especially as most reputable astronomy shops will take it back if it doesn't meet expectations.

John