First try out of focal reducer lens supplied by bert

[5ash]

Bert kindly supplied me with a 13,5 cm focal length achromatic lens to use as a focal reducer with my Lx90. Tried different positions for lens but found best spot to be 3-4 cm inside the visual back. Took pics with 350d with moon in the sky of "the Ghost of Jupiter"( stacking 30sx2+60sx2+90sx2) ," Eta caina nebula (stacking 60sx2+90sx2)" & 'The Sombrero Galaxy M104 (stacking 60sX2+90sx3)". All were at iso 1600 ,dark and flat subtracted in astromix and cropped and resampled in photoshop. M104 was filtered in neat image. I am still experimenting and am only using medium jpeg captures. I realise all the problems with jpegs and will start taking raws when i am satisfied with the equipment.
philip

[ving]

not too shabby :)

i know that it is of little consequence but i am used to the sombrero up the other way... the poor mexican is standing on his head :)

yeah i know, i am weird :screwy:

[avandonk]

Ash that looks like a focal reduction of 0.4. Could be a bit ambitious. Thats why the outer stars are bloated.

The formula for focal reduction is (F - D)/F , where F is the focal length of the FR and D is the distance from FR lens to sensor. I would try it as close to the sensor as possible. This should result in a FR of 0.6 to 0.7. The other thing is to use a longer focal length lens. For your Canon 350D (all EOS) the distance between the sensor and bayonet flange front is 44mm.

Bert

[5ash]

Bert I first tried to put the lens in the tube of the t-adapter and this resulted in abberations looking like extreme coma.Have attached pic of omega centuari in that configuration it looks interesting ! will experiment further with your advice .
philip