Limerick Astronomy Club

Dave Lillis kindly loaned me his Meade 4000 series f/6.3 focal reducer/field flattner to try it out. With the LX200R 10" telescope and the Canon EOS 400D digital camera attached I found that the whole disc of the Moon was too big with this arrangement. I was not around last weekend when the Moon was up , so I tried focal reducer on Orion nebula.
First image is a photoshopped image from before Christmas without the focal reducer.


This second image is with the focal reducer. It is 180 second exposure and there is some star trailing, but the scope is not equatorially mounted. I think you can clearly see the difference the focal reducer makes to the field of view.

Hi Conn,
There is substantial difference in the size of the FOV there, worth thr effort I think. A pity about the moon not fitting in. One thing you might try is putting the focal reducer right onto the back of the scope and put the camera directly onto it, so removing the micro focuser from the system, this might help as the focal reducers power is a function of the focal reducer - camera spacing.

You need to work out the periodic error in the drives, doing that will eliminate most of the drive error. Alot of what you're seeing there isn't field rotation.

wow thats some difference.
Conn,
to beat the startrailing,
you could try taking a series of shorter shots
(say 5, 40sec ones) at a higher ISO
then stacking them.

Lads, Thanks for the kind supportive comments. Dave, I have yet to try out the focal reducer on a full Moon -- did not get that opportunity last weekend. May I hold on to the F/reducer till next full Moon please?

Yes, I will look at removing the micro focuser from the chain and see what difference that would make.

I thought that the periodic error could not be tackled unless the scope was permanently equatorially mounted?

Frank, as you can see from the image of Jupiter i posted tonight -- I have a fair idea of Registax processing avi files. But, I do not know how you manage a series of short exposure shots and get them to stack. Recently John O'Mahony suggested an observing session devoted to imaging --- Dave asked for specifics for such an event --- I think this is a good example of what we could try. Any comments John?

So, imagine a night on the hill where a demo of Saturn being imaged by web cam and Orion nebula imaged by digital camera and Registax then applied -- and maybe photoshopped? This would be an excellent use for the club laptop

I know that our members have heard this imaging procedure explained but I think if we had a few members actually involved in focussing the scope or managing the file creation etc the learning experience would be more real and might get some more to try their hand at it.

Tell you what, the 2 meetings in mid summer are open meetings, one can easily be turned into an image capture and registax processing talk, very easy, or use one of the talk slots between now and then if the speaker doesn't show. I can bring in the 4 inch refractor, webcam and using the club laptop I could work on a distant street light out the window and work from start to finish on it.
OR/AND
we can do an imaging night the next time we go up to the hill, people can bring their laptops, scopes and webcams. We can announce this at the meeting next week if this is what you want, just ask and I'll deliver.

I remember you did that not so long ago (just over a year or so)
I found it very helpful.
I like the idea of doing it up on the hill but power supply would be
a major issue.

Nice work Conn also thanks to Dave & Frank for tech analysis and tips

Conn Buckley wrote: I thought that the periodic error could not be tackled unless the scope was permanently equatorially mounted?.

ah yes, I forgot you don't use a polar wedge.