[Bolts_Tweed (Mark)]

Gday

Am I the only one with this problem???

I have found that if I shoot say 5 min RGB subs with the astrodon filters and I then shoot a luminosity image I cant get the half flux diameter down to anywhere near what I get in the RGB - I have reduced the exposure down to say 30 seconds as an experiment and still the 1/2FD is 60 to 75% or larger than the RGBs - Sry this is using an ST8300 and a AP130EDT or a Televue np101is so I am fairly confident with the optics performance.

After much experimentation I am at an end - I know I should email Don Goldman but I thought I would check if anyone has a similar experience.

In extreme frustration I am going to try turning the filter around next weekend just in case they are directional but I cant find any reference to cirectionality on Dons website.

Anyone have any ideas or similar experiences - I am looking forward to a LRGB image instead of HaRGB for a change. I am keen to have a crack at the IFN in Apus this weekend and Ha just isnt going to help too much.

Mark Bolton