Reducers - Question

[Martin 2]

When taking pics manualy through the eye piece on the gps 8 would a focal reducer improve things or not (dso )

M2

[GordonCopestake]

The focal reducer usually just reduces the focal length from f/10 to f/6.3 (or f/3.3) this gives you a wider field of view. A lot of them are also field flatteners so you get sharper stars. When you say improve things do you mean the quality of the image or the ease of taking images?

[Martin 2]

I wondered if by shortening the focal lenght I would get more info on the ccd in the 40 secs that I hold the shutter open, I took 20 pics of m31 and stacked them in deepsky stacker but was dissapointed with the result, I know its not a lot of subs but when you are manualy taking each pic I wundered if it would be better with a reducer.

M2

[GordonCopestake]

The faster the scope the shorter your exposures can be but the larger the field of view...

One solution i use to good effect is set your camera to 30 seconds or whatever your light pollution will take then use a rubber band around the shutter release with a m10 nut. The shutter being held down takes a 30 second sub, then another... then another.... then another.... whist you are in doors nice and warm having a cuppa. I can take 70 subs using this method with my D70 quite happily before my battery runs out

[Kaptain Klevtsov]

Great tip Gordon, I'll try that one!

Captain Chaos

[Martin 2]

I already use the elastic band and nut method ( Its a bit hit and miss on my camera ) so I have ordered a remote for it.

its just that 20 stacked pics doesnt seem to show any more detail than 1 pic.

M2

[Kaptain Klevtsov]

Have you tried Registax Martin? I use this and it usually gets the job done. Won't work on an Alt. Az. type mount though.

Captain Chaos

[daz]

What ISO setting is the camera at Martin?

You may need to up it one or two stops

[MartinB]

Martin, you will struggle with the SCT at it's native F10 to get enough light. The other problem is you are imaging at 2000mm which is always going to be problematic. I have only ever once attempted to image with the NS8 at F10 on the Eskimo Neb because it is so small. the best I could manage was 20secs and even then I had to discard a lot of the subs because of excessive trailing The end result wasn't very good. Focal reducers are a big help. The Celestron F6.3 reducer works very well although you will probably get significant vignetting with an SLR - you will have to get some "flats" which is an art in itself. Avoid the Meade F3.3 reducer which is designed for CCDs with their smaller chips. The F3.3 is great with modded webcams such as the Atik 2HS.

[Martin 2]

I only have 3 settings for ISO on this camera, 100, 200and 400, Ive been trying 200 and 400 for dsi.

I,ll have to get a reducer I think and give that a whirl.

Thanks for the input guys, great help

M2