Rosette

[Geoff45 (Geoff)]

Here's a pic of the Rosette nebula from about 6 weeks ago.

Details:

WO ZS110 Apo with 0.8 Focal Reducer
Canon 350D, unmodified
Autoguided with Orion Starshoot AG
6 x 10min @ 800ISO lights, calibrated with darks only
Losmandy GM8

A lot of work went into beating up the red in PS. I also need to fiddle with the so-called field flattener, because the corner stars are quite elongated. It's not the same all round because I cropped some of the left edge--nebula wasn't quite centered.
Geoff

[gbeal]

Nice shot Geoff.
How come the field flattener hasn't flattened the field?
Gary

[Geoff45 (Geoff)]

Originally Posted by gbeal

Nice shot Geoff.
How come the field flattener hasn't flattened the field?
Gary

Not entirely sure, but I was speaking to Iceman at the SPSP and he mentioned he had a similar problem, which he thinks he has fixed. It's a bit hard to explain without a picture or the object in hand, but basically there are three screws which if not tightened up correctly may set the distance between camera and FF slightly wrong. Haven't had a chance to retry.
Geoff

[gbeal]

I wondered that. While I thought the dedicated FF would be a fixed distance, the likes of my Baader MPCC needs about 56mm from rear to chip, and anything else makes a difference.
Gary

[Alchemy (Clive)]

remarkable amount of Ha recorded for a stock camera

[winensky]

Lovel image. Good range of colours. I was going to ask about the Ha too. It seems that the modded DSLRS are capable of picking up this region well and so provide a balanced spectrum. Am I correct in this or have I missed something being done in the processing?

Kind regards
Matt

[Geoff45 (Geoff)]

Originally Posted by winensky

Lovel image. Good range of colours. I was going to ask about the Ha too. It seems that the modded DSLRS are capable of picking up this region well and so provide a balanced spectrum. Am I correct in this or have I missed something being done in the processing?

Kind regards
Matt

Well I certainly bumped up the red in Photoshop, but there has to be something there to play with in the first place. Unmodified DSLRs do pick up H alpha--they are just not very good at it. I think they only record about 10% of the H alpha

[Phil]

Nice shot Geoff love the colour.
Phil