Coma corrector for 200P

[Astroblagger]

Hello im looking for some advice/help iv got a SW 200p and plan to use it for imaging with a dslr, can anyone suggest the correct one to get as i hear some people have difficulty achiving focus with a corrector in place?

[Black Knight]

I use the official Skywatcher item Coma Correctors, plus the M48 adapter. I haven't experienced any problems focussing. I know many other people use the Baader MPCC. No idea what focussing is like with that I'm afraid.

[Glider]

Black Knight, what focuser has your 200P got, low profile Crayford, rack and pinion?

[Astroblagger]

Do you have the sky blue SW 200p? with normal crayford focuser or is it the shortened focuser?

[Black Knight]

Black Knight, what focuser has your 200P got, low profile Crayford, rack and pinion?

Normal Crayford. With the sporty alloy wheels . The OTA has the Black Diamond finish.

Edited January 25, 2011 by Black Knight

[Glider]

I guess my old R&P wouldn't get enough in focus then?

Edited January 25, 2011 by Glider

[Black Knight]

TBH, I don't know. Without the Coma Corrector, I had to use the Direct Camera Connection or a Barlow to achieve focus. T-Rings and T-adapters didn't have enough in-focus on my Crayford. Does the R&P focuser have a direct camera connection, and if so, will the DSLR focus? If it does, then perhaps the SW CC will be OK.

Edited January 25, 2011 by Black Knight

[Glider]

That is interesting, it sounds like the corrector effectively gave you some more in focus.

[Black Knight]

Yeah, it did . I did take a bit of a gamble on it TBH. I assumed that SW wouldn't sell a CC designed for DSLRs if they hadn't tested it first . It comes with an adapter which replaces the "ring" (I don't know the correct term for this) on the focus tube i.e. the ring you drop the eyepiece adapter into. Maybe that makes a difference?

[Glider]

Cheers.

[Astroblagger]

can you post a pic of the focuser? just to be sure as its abit of money to waste if the coma corrector doesnt work.

[cs1cjc]

The Altair Astro coma corrector (same as the Astro-Tech, optical design by Roger Ceragioli, manufactured by GSO I understand) works well for me.

Altair Astro Photo Visual Coma Corrector and Field Flattener for Newtonian reflectors

Back focus should not be an issue - the coma corrector gives about 47mm additional out focus. The corrector screws on to a 2" filter, M48 thread. For photographic use, the Astro Engineering 2" to T-mount adaptor, AC493, gives the corrector just about the perfect spacing from the image plane.

Adaptors for telescopes

Edited January 26, 2011 by cs1cjc

[kotitonttu]

On 25/01/2011 at 21:44, Black Knight said:

I use the official Skywatcher item Coma Correctors, plus the M48 adapter. I haven't experienced any problems focussing. I know many other people use the Baader MPCC. No idea what focussing is like with that I'm afraid.

Was your focuser like this 

 

[alacant]

On 25/01/2011 at 20:41, Astroblagger said:

anyone suggest the correct one to get

Hi

200p?

Old, new, blue tube, black tube, Crayford, rack and pinion... This one just works. 

Does corner to corner over aps-c at a back focus of 75mm giving fl ~1090mm. Oh, don't forget to remove the visual attachment;)

Cheers

Edited August 16, 2021 by alacant