ASTRO: NGC 4565

I have quite a lot of data waiting to be processed from the first half of
May, but most of it is either not really good or has some problems that make
it difficult to process. In this case I had one night of NGC 4565 at f/6.4
where focus did shift and compromised image detail, the other night I used
my new Baader Steeltrack OAZ, which allowed me to lock down the main mirror
properly, which prevents focus shift. The focuser between the focal reducer
and the camera gives a focal ratio of f/5.7, so the image had a much larger
field than the first one.

Taken from the middle of Berlin with a 10" Meade ARC at f/5.7 and f/6.4 on a
G11 mount, SXV-H9 camera, 44x5 minutes. Colour will follow.

The picture can also be found at
http://ccd-astronomy.de/temp/4565-23x5u21x5smallgut.jpg

Stefan

Stefan Lilge wrote:

I have quite a lot of data waiting to be processed from the first half of
May, but most of it is either not really good or has some problems that make
it difficult to process. In this case I had one night of NGC 4565 at f/6.4
where focus did shift and compromised image detail, the other night I used
my new Baader Steeltrack OAZ, which allowed me to lock down the main mirror
properly, which prevents focus shift. The focuser between the focal reducer
and the camera gives a focal ratio of f/5.7, so the image had a much larger
field than the first one.

Taken from the middle of Berlin with a 10" Meade ARC at f/5.7 and f/6.4 on a
G11 mount, SXV-H9 camera, 44x5 minutes. Colour will follow.

The picture can also be found at
http://ccd-astronomy.de/temp/4565-23x5u21x5smallgut.jpg

Stefan

I'm surprised the mirror lock on your scope didn't hold the mirror for
you. It works fine on my much heavier 14" mirror. Is it engaging?
Mine arrived DOA but found some web page on how to remove the knob and
get inside to fix it. I still have a lot of focus change due to
temperature and had to go to a temperature compensating focuser to solve
it. Otherwise it was refocus every 10 minutes.

Looking through my inventory of your images this appears your best 4565
to date so the new scope is working for you. Though the 8" allowed all
of 4562 to be seen rather than just its nose. Awaiting color.

I wanted to get color data to go with my mono version of this guy.
Weather never cooperated. So little dark sky left hardly worth imaging
for the next couple months. Has to be even worse for you!

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".

Now here is the colour version of my NGC 4565 shot. COlour is spurious here
because I only have 3x5 minutes each for green and blue and 6x2 minutes for
red. Red has shorter subexposures because it was taken in a different night
with a faster focal ratio and a brighter sky. An additional problem were
wild gradients in the green and blue channel, so I had to be choose a
"sublime" setting for colour in order not to show the noise, gradients etc
too obviously.

The picture can also be found at
http://ccd-astronomy.de/temp/4565colourgut.jpg

Stefan


"Stefan Lilge" schrieb im Newsbeitrag
...
I have quite a lot of data waiting to be processed from the first half of
May, but most of it is either not really good or has some problems that
make
it difficult to process. In this case I had one night of NGC 4565 at f/6.4
where focus did shift and compromised image detail, the other night I used
my new Baader Steeltrack OAZ, which allowed me to lock down the main
mirror
properly, which prevents focus shift. The focuser between the focal
reducer
and the camera gives a focal ratio of f/5.7, so the image had a much
larger
field than the first one.

Taken from the middle of Berlin with a 10" Meade ARC at f/5.7 and f/6.4 on
a
G11 mount, SXV-H9 camera, 44x5 minutes. Colour will follow.

The picture can also be found at
http://ccd-astronomy.de/temp/4565-23x5u21x5smallgut.jpg

Stefan

Very nice Stefan!


John N. Gretchen III
N5JNG NCS304
http://www.tisd.net/~jng3

Rick, the mirror was only locked in one of the two nights. When it was
locked I didn't have any focus shift. Actually with the mirror lock on I
seem to have less problems with focus shift with the 10" ACF scope than I
had with my C8, in spite of the C8's smaller mirror.
Actually it took one of your earlier postings to get me to really tighten
the mirror down. The manual just says that you should turn the focus lock
"until it feels tight". That of course is not a very precise statement, so I
stopped when the focus lock started turning noticeably harder than in the
beginning. Of course you have to turn it until it can't be turned any more,
but I didn't dare to try that at first, as I don't have a clue how the
mirror lock works (might damage the mirror if tightened too strong).

Stefan

"Rick Johnson" schrieb im Newsbeitrag
...


Stefan Lilge wrote:

I have quite a lot of data waiting to be processed from the first half of
May, but most of it is either not really good or has some problems that
make it difficult to process. In this case I had one night of NGC 4565 at
f/6.4 where focus did shift and compromised image detail, the other night
I used my new Baader Steeltrack OAZ, which allowed me to lock down the
main mirror properly, which prevents focus shift. The focuser between the
focal reducer and the camera gives a focal ratio of f/5.7, so the image
had a much larger field than the first one.

Taken from the middle of Berlin with a 10" Meade ARC at f/5.7 and f/6.4
on a G11 mount, SXV-H9 camera, 44x5 minutes. Colour will follow.

The picture can also be found at
http://ccd-astronomy.de/temp/4565-23x5u21x5smallgut.jpg

Stefan

I'm surprised the mirror lock on your scope didn't hold the mirror for
you. It works fine on my much heavier 14" mirror. Is it engaging? Mine
arrived DOA but found some web page on how to remove the knob and get
inside to fix it. I still have a lot of focus change due to temperature
and had to go to a temperature compensating focuser to solve it.
Otherwise it was refocus every 10 minutes.

Looking through my inventory of your images this appears your best 4565 to
date so the new scope is working for you. Though the 8" allowed all of
4562 to be seen rather than just its nose. Awaiting color.

I wanted to get color data to go with my mono version of this guy. Weather
never cooperated. So little dark sky left hardly worth imaging for the
next couple months. Has to be even worse for you!

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".