4.7 inch Frac VS 6 inch SCT

[Mamsoth]

Hi everyone, just have a quick question regarding the best scope to use for planetary/Lunar imaging. I'm currently using a 120mm Celestron Omni Refractor and was thinking about getting a Celestron C6 SCT and was wondering if anyone could comment as to whether the C6 will outperform the frac.

Thanks and clear skies

Matt

[brianb]

Not much difference .... why not go up to the C8 tube, it'll still be lighter & easier for a mount to manage than the frac, and the extra aperture does help!

If buying an SCT for the first time, don't forget to budget for a dew shield of some sort. And you WILL need a focuser addon of some sort for imaging - the standard focuser is rather coarse as well as being prone to "mirror flop".

[nightfisher]

If buying an SCT for the first time, don't forget to budget for a dew shield of some sort. And you WILL need a focuser addon of some sort for imaging - the standard focuser is rather coarse as well as being prone to "mirror flop".

what would you suggest as a focuser ad on

[paraman]

If buying an SCT for the first time, don't forget to budget for a dew shield of some sort. And you WILL need a focuser addon of some sort for imaging - the standard focuser is rather coarse as well as being prone to "mirror flop".

what would you suggest as a focuser ad on

I bought one of these for my cpc800, there probably are better ones but there is the question of even more additional cost.

Antares Antares dual-speed Crayford focuser for SCTs

[Mamsoth]

Not much difference .... why not go up to the C8 tube, ".

I've only got a maximum budget of about £400 so I'm looking for a second hander, if I'm lucky enough to come across a C8 for £400 or less I'll certainly be snapping it up!!!

[russ]

Not much difference .... why not go up to the C8 tube, it'll still be lighter & easier for a mount to manage than the frac, and the extra aperture does help!

If buying an SCT for the first time, don't forget to budget for a dew shield of some sort. And you WILL need a focuser addon of some sort for imaging - the standard focuser is rather coarse as well as being prone to "mirror flop".

Depending on the dew in your area, i would allow for more than just a dew shield. If your area is prone to dew, the last thing the dew shield will help with is the dew. The corrector will be gone in minutes, with or without the dew shield. Better to allow for some active anti-dew solution such as heat tapes and a controller.

This is the draw back to the SCT. Great scope but needs a fair few accessories to work well.

[Trevor-Austin]

I bought one of these for my cpc800, there probably are better ones but there is the question of even more additional cost.

Antares Antares dual-speed Crayford focuser for SCTs

That's just scopesnskies trading as a different name isn't it? Why have 2 identical sites and different trading names? Confused!

[John]

I owned a C8 for a while and heartily agree with Russ with regards to dew prevention - I used a heated dew band which was generally OK on it's own but I did need a dew shield as well on really bad nights.

I managed to pick up a 10 year old C8-plus on a fork mount in very nice nick for £350 a couple of years back - it had a bit of mirror shift but was optically very nice - fantastic views of Saturn on the best nights with an 8mm Tele Vue plossl

[brianb]

If your area is prone to dew, the last thing the dew shield will help with is the dew. The corrector will be gone in minutes, with or without the dew shield.

A dew shield made to extend twice as long as its diameter and made of a good insulating material (camping mat is good) will not be a complete solution but will help a lot. In my experience a heater tape on its own is little use; with a good dew shield, you can turn the power on the heater tape way down - saving power tank capacity - and still avoid the dew. In really bad conditions, without a heater tape but with a good dew shield, you'll get a couple of hours more than you would without it.

Commercial dew shields are usually (a) too short and ( made of material which is not very good insulator. AstroZap dew shields are too short but are at least nicely lined with insulating flocking material, they're more effective than most, but not as good as a "home brew".

[russ]

A dew shield made to extend twice as long as its diameter and made of a good insulating material (camping mat is good) will not be a complete solution but will help a lot.

I think that really depends on individual locations. I found the dew shield, regardless of type, materiel or dimensions, failed to help very much at all. Only adding a few minutes at best. The only way i could successfully use an SCT was the combination of the shield and heat tape.

But 15miles down the road, Rob used his SCT with only a dew shield and then only for light scatter prevention. Rarely had any dew.

[Mamsoth]

If buying an SCT for the first time, don't forget to budget for a dew shield of some sort. And you WILL need a focuser addon of some sort for imaging - the standard focuser is rather coarse as well as being prone to "mirror flop".

Basically I'm after a scope whos sole job will be Lunar/Planetary imaging, the SCT route sounds like it will end up being too expensive with all the extra accessories needed. Does anyone have any ideas then for a good Lunar/planetary imaging scope for around £400 (secondhand if necessary and only the OTA as I already have an EQ3-2 Mount).

[brianb]

Does anyone have any ideas then for a good Lunar/planetary imaging scope for around £400 (secondhand if necessary).

Skywatcher Explorer 150PL EQ3-2 with motor drive. Plus a 2.5x Powermate.