M-47, Open Star Cluster in Puppis; plus star clusters NGC 2423 and NGC 2425

Not much imaging going on in New York lately!

Mostly snow! On the few clear nights it's cold: for example -18F a few days
ago - not counting wind chill.

However, I did get a chance to take a few images last week. I'm working on
completing my collection of Messier Objects and most that I don't have are
so large that they require a small scope for imaging.

The attached is a 10-minute exposure with a Canon Rebel DSLR thru a Brandon
80mm triplet. However it a crop of the full field. The scope has a lot of
field curvature and I have been unable to find a corrector that will work
with its 1.25-inch focuser.

For those with fast internet connections, here is a large full rez version:
www.kopernik.org/images/archive/m47.jpg

George N

George Normandin wrote:
Not much imaging going on in New York lately!

Mostly snow! On the few clear nights it's cold: for example -18F a few days
ago - not counting wind chill.

However, I did get a chance to take a few images last week. I'm working on
completing my collection of Messier Objects and most that I don't have are
so large that they require a small scope for imaging.

The attached is a 10-minute exposure with a Canon Rebel DSLR thru a Brandon
80mm triplet. However it a crop of the full field. The scope has a lot of
field curvature and I have been unable to find a corrector that will work
with its 1.25-inch focuser.

For those with fast internet connections, here is a large full rez version:
www.kopernik.org/images/archive/m47.jpg

George N

Full image looks good. A little cropping and the curved field would
vanish. I know, I hate to crop out one star. Actually it's not all
that bad. I've got a lot of eyepieces that would do worse on that size
field.

I remember the first time in the early 60's when I went after M47 in my
10" F/5. It was easy in the finder but when I looked in the eyepiece I
didn't see it. Figuring the finder was off I panned around and ran into
NGC 2423. It looked so much like M47 in my old 2.4" refractor I
thought it was it. But looking in the finder I saw it faintly right on
the cross hairs. I finally realized I'd seen 47 after all but didn't
recognize it as a cluster.

I think 2423 is in the Herschell 400. I know 47 is which never made any
sense why they included it and left out 2425. Of the 3, it was my
favorite, and most challenging as well.

I do like the full image even with the curved field.

Rick
--
Correct domain name is arvig and it is net not com. Prefix is correct.
Third character is a zero rather than a capital "Oh".

Very nice picture George. Apart from the edges of the field stars look good,
the scope has good colour correction.

Stefan

"George Normandin" schrieb im Newsbeitrag
...
Not much imaging going on in New York lately!

Mostly snow! On the few clear nights it's cold: for example -18F a few
days ago - not counting wind chill.

However, I did get a chance to take a few images last week. I'm working on
completing my collection of Messier Objects and most that I don't have are
so large that they require a small scope for imaging.

The attached is a 10-minute exposure with a Canon Rebel DSLR thru a
Brandon 80mm triplet. However it a crop of the full field. The scope has a
lot of field curvature and I have been unable to find a corrector that
will work with its 1.25-inch focuser.

For those with fast internet connections, here is a large full rez
version: www.kopernik.org/images/archive/m47.jpg

George N

"Stefan Lilge" wrote

....
Very nice picture George. Apart from the edges of the field stars look
good, the scope has good colour correction.


Stefan,

Those old Brandon 80mm's have Roland Christen made triplet lenses. When
sold back in the 1980's they were optimised for visual and film, not CCD or
digital. We have two of them. One is the "finder" on the RC20 and the second
will go onto the Astro-Physics refractor as soon as we get around to it.
They came with a special Barlow lens to screw into the diagonal to
correct the field curvature. However that also extends the focal length.
I've looked into purchasing a corrector, but so far I've not found one for a
1.25-inch focuser. The owner of VERNONscope has looked thru his "junk pile"
of old parts for a 2-inch focuser, but he has been unable to find one. So I
guess I'll have to live with the fuzzy corner stars, or longer exposures.

George N