M46 - From Brightsky Observatory III.

[Astroman (Andrew Wall)]

Hi all,

Getting used to the new imaging setup and lastnight was the first time I had guiding working properly. Happy with the results, but annoyed I didn't check my focus better.

M46, Canon 1100D, 8" f/4 Astrograph. 20 x 300sec, ISO 400. Astronomik CLS filter and MPCC.

Larger, hires image.
http://www.astrobin.com/full/72049/0/

There is a little bit of cma still present, anyone know how to remove it? I am guessing spacers, but where do I get them from or should I put shims between the Camera adapter and the Corrector until the coma goes away?

[tilbrook@rbe.ne (Justin Tilbrook)]

Hi Andrew,

Not bad for challenging conditions, moon and light pollution.

I think your coma corrector is already at the correct spacing 55mm. The type 1 baader is best at F/L of 4.5 to F/6.

Here's the blurb about the type 3, I think this applies to the type 1 too.

To get the best astrophotos with a DSLR camera, the Baader MPCC Mark III Multi-Purpose Coma Corrector is ideal. For imaging with digital SLR cameras, only the MPCC MkIII is needed - additional spacer rings are not required. (You WILL need a T-ring for your particular camera model, of course). The MPCC MkIII is designed for a nominal 55mm distance from the mounting flange to the camera sensor (55mm is the standard flange-to-sensor distance for most DSLR cameras, measured from the front of the T-ring to the image plane). For use with CCD cameras, you may need one or more T-thread extension or "spacer" rings to achieve the correct distance between the MPCC MkIII and the camera's imaging sensor. (Orion carries a T-thread Spacer Ring Kit, sold separately).

Here's a link to setup with a DSLR.
http://www.baader-planetarium.com/pdf/mpcc_e.pdf
My type 3 still produces a little coma.

Cheers,

Justin.

[cometcatcher (Kevin)]

That's a good image. The coma is barely noticeable and the CLS filter really makes the nebula stand out.

[Astroman (Andrew Wall)]

Thanks Justin and Kevin.

I was surprised not more came out in the exposure time, most likely because of the moon and light pollution, really would like to get the camera modded and play around with Ha filters. Not as good as dedicated CCD but good for a bit of a play..

Thanks again guys.