ASTRO: Quick and dirty test of Baader Emission Line filters at long focal length on Crab

I had a brief opening in the clouds last night so I tried the 18" f/12.6
classical cass with the Cm10 (KAF3200ME) and Focal reducer (f/7.2 final)
with my set of Baader emission line filters. I have been working my way
through a few different optical systems using them. This is the first time
for me to use them over 3000mm focal length.

I took some images of the Crab nebula: 3 x 20 minutes of Halpha, 2 x 20
minutes of [SII] and [OIII]. The seeing was not all that hot.

The image scale works out to be 0.42"/pixel before resampling so I need
pretty darned good seeing to get a sharp image using this setup.

I plan to work on this over the coming weeks and when I can get good seeing
maybe get some nice final image.

The Baaders are working fine I'd say. I just need good seeing and more
exposure time..

That looks very promising. 0.42"/pixel is very challenging indeed, that's
why I am quite happy to image at a smaller scale. There are some good nights
of course where a longer focal length would give me more detail, but on an
average night I wouldn't gain a lot.

Stefan

"Richard Crisp" schrieb im Newsbeitrag
. ..
I had a brief opening in the clouds last night so I tried the 18" f/12.6
classical cass with the Cm10 (KAF3200ME) and Focal reducer (f/7.2 final)
with my set of Baader emission line filters. I have been working my way
through a few different optical systems using them. This is the first time
for me to use them over 3000mm focal length.

I took some images of the Crab nebula: 3 x 20 minutes of Halpha, 2 x 20
minutes of [SII] and [OIII]. The seeing was not all that hot.

The image scale works out to be 0.42"/pixel before resampling so I need
pretty darned good seeing to get a sharp image using this setup.

I plan to work on this over the coming weeks and when I can get good
seeing maybe get some nice final image.

The Baaders are working fine I'd say. I just need good seeing and more
exposure time..

I will probably shoot 2x2 binned next time. I need to make a library of
darks for that binning anyway....


"Stefan Lilge" wrote in message
...
That looks very promising. 0.42"/pixel is very challenging indeed, that's
why I am quite happy to image at a smaller scale. There are some good
nights of course where a longer focal length would give me more detail,
but on an average night I wouldn't gain a lot.

Stefan

"Richard Crisp" schrieb im Newsbeitrag
. ..
I had a brief opening in the clouds last night so I tried the 18" f/12.6
classical cass with the Cm10 (KAF3200ME) and Focal reducer (f/7.2 final)
with my set of Baader emission line filters. I have been working my way
through a few different optical systems using them. This is the first time
for me to use them over 3000mm focal length.

I took some images of the Crab nebula: 3 x 20 minutes of Halpha, 2 x 20
minutes of [SII] and [OIII]. The seeing was not all that hot.

The image scale works out to be 0.42"/pixel before resampling so I need
pretty darned good seeing to get a sharp image using this setup.

I plan to work on this over the coming weeks and when I can get good
seeing maybe get some nice final image.

The Baaders are working fine I'd say. I just need good seeing and more
exposure time..

Looks great, what mount?


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

"john" wrote in message
m...
Looks great, what mount?


ap1200gto

the scope is big and heavy: 18" f/12.6 classical cassegrain

the 1200 is right at its limit i'd say




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

Richard Crisp wrote:

"john" wrote in message
m...

Looks great, what mount?



ap1200gto

the scope is big and heavy: 18" f/12.6 classical cassegrain

the 1200 is right at its limit i'd say




AP now has the 3600 coming out at 250 lb tube weight and through the
axis cabling. It should carry your next and bigger scope well.

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".

"Rick Johnson" wrote in message
...


Richard Crisp wrote:

"john" wrote in message
m...

Looks great, what mount?



ap1200gto

the scope is big and heavy: 18" f/12.6 classical cassegrain

the 1200 is right at its limit i'd say




AP now has the 3600 coming out at 250 lb tube weight and through the axis
cabling. It should carry your next and bigger scope well.

I should buy one for my observatory I plan to build

that and a 24"

"Richard Crisp" wrote
....
I had a brief opening in the clouds last night so I tried the 18" f/12.6
classical cass with the Cm10 (KAF3200ME) and Focal reducer (f/7.2 final)
with my set of Baader emission line filters. I have been working my way
through a few different optical systems using them.......

Richard,

First: Great image!!

What is the concern with different focal lengths on the filters? Is there
some effect from the angle of the in coming light cone?

What's your opinion on the Baader filter set?

George N