[tilbrook@rbe.ne (Justin Tilbrook)]

Hi,
Here’s another image of Eta, please disregard the star images. Although I’ve got closer to the correct spacing for the coma corrector it’s still not producing the sharp round images I would like.
The BINTEL corrector is actually designed for F/4.5 but they say it will work at 3.5 to 6.0, I have my doubts.
What correctors do others use for an 8” f/4 astrograph??
To the image.
This time I have more data, 40 minutes in total, would have liked more but the cloud rolled in. I managed to preserve star colour this time, needed to get quite heavy handed to bring out the red in the nebula. My canon 1100D is not modified, so doesn’t register in the red very well.
I’ve been using a lot of the tips you guys have supplied and I think I’m improving?
Maybe the weather will be kind on the weekend so I can get more data.
Equipement.
Telescope 8” f/4 astrograph – HEQ pro 5 mount – Orion mini guider.
Camera. Canon 1100D – BINTEL 2” coma corrector.
8 x 5 minute subs – 7 x 5 minute darks – 7 flats – 7 bias, at ISO 400.
Median stack in DSS.
Processed in Photoshop.
Cheers,
Justin.