M35 - 24/03/2007

Image taken last night.
12" f/6.3, ST8, 30 x 20sec exposures



Regards,

One of my favourite clusters Michael,
How did you find using the F6.3 reducer ? how did the tracking work out with it

A beautiful image,Michael, of one of the most marvellous binocular sights in the sky.

Sue French describes it thus:
"The cluster is only about 150 million years old.
While gazing at M35 you might be stepping on stones older than that." (From "Celestial Sampler".S&T book.)

My own impressions, in binoculars from a truly dark sky, show the two bright stars Mu and Eta Geminorum seeming to hang in the foreground and a string of stars loop back to M35, which seems to lie at the bottomless depths of infinity.

There is something about that area that puzzles me.

When I was young (20years ago) the stars Mu and Eta Geminorum were known as "Tejat Prior" and "Tejat Posterior" .(I still have atlases with those names in.)

In modern atlases the Tejat names are gone,Mu Geminorum has no name and Eta Geminorum is called "Propus".

Does anybody know why those two star names have changed in the last two decades?

Peter.

One of my favourite clusters Michael,
How did you find using the F6.3 reducer ? how did the tracking work out with it

Dave,
I used the 6.3 reducer directly before the camera i.e. between the WO focuser and the camera rather than on the back of the SCT. Centre of image was fine but the flatness drops off towards the outer edges.
Image was unguided.

Michael - its a nice image.

One thing that strikes me though is that the stars seem lop-sided - they seem brighter to the lower right (4 O'Clock position). It almost looks like it could be tracking but I'm not so sure. Fainter stars look good.

Could it be the position of the reducer? I don't know what the best location is for a reducer.

Dave

I think it is the reducer Dave. The stars did seem a bit strange alright - some appear fine whilst others seem to almost have a slight elongation to them. I will look at the camera again today and see if the main chip can be centered relative to the optical path. I'll also place the reduce directly on the back of the OTA and we'll see if it makes any difference.

Cheers,