NGC891 - side on galaxy

[SimonfromSussex]

Taken last night, about 10 each R/G/B 5min subs.

C925, 0.6 focal reducer and atik 314L.

I took a lum layer about two weeks ago and here is the layer result. However it was lower in the sky then, my focus was good but it looks slightly out of focus? I think the atmosphere has mushed the data a bit?

As always any advice greatly received.

Simon.

[Gina]

Nice

[SteveA]

Hi Simon,

Nice images..I have to say I prefer the rgb image!

As you say the luminace subs do seem to be suffering, though I would be tempted to say this looks more like a guiding issue..there's definately some strange shaped stars in there, which you don't have in the rgb.

NGC891 is sitting in a fairly rich star field and as I found myself last weekend whilst imaging this target (also with 5 mins subs), there's a tendancy for the forground stars to bloat. I ended up processing to reduce the size of these stars...

[SimonfromSussex]

Thanks Gina.

Thanks Steve, you might well be right on the guiding. Looking at my individual lum subs there are some that are not quite round.

I only have a set of basic RGB filters which don't help with the stars but I hope to upgrade soon as I think this will make a difference.

Have you posted your NGC891 pic? I'd love to have a look?

I ran them both through focus magic and I think this has tightened them a bit.

RGB:

LRGB:

[Gina]

Better

[SteveA]

Hi Simon,

I did post this in another thread....but probably easier t re-post here..

This is luminance only...20x300secs with my f4 newt and the Atik 314L.

I was hoping for some more subs this weekend....but it didn't happen!

Steve

[SimonfromSussex]

Cheers Steve, nice pic, that's really handy to compare.

You are right, there are five or six large stars in the for ground in mine that need toning down!

An f4 newt is my next upgrade, how are you finding the quattro?

Did you go steel or carbon fibre? If you went steel I'd be really interested to know how you think the eq6 handles the weight?

[michael.h.f.wilkinson]

First of all, very nice capture, proving SCTs can produce the goods on DSO photography. I think I have spotted another problem, which stems from the fact that the RGB and luminance images have been taken at different orientations. This means the luminance channel has been rotated which caused some kind of error akin to improper debayering. There seems to be a mesh-like pattern over the galaxy. I think this is the root of the problem, more so than focus and guiding problems.

[SteveA]

Cheers Steve, nice pic, that's really handy to compare.

You are right, there are five or six large stars in the for ground in mine that need toning down!

An f4 newt is my next upgrade, how are you finding the quattro?

Did you go steel or carbon fibre? If you went steel I'd be really interested to know how you think the eq6 handles the weight?

Hi Simon,

Well I love my quattro....I went the cf route principly because of the weight....but I also wanted a slightly faster setup

I upgraded to this from an earlier version of the SW 250 newtonian...f4.7 model with the steel OTA, light blue paint job.

The weight difference is significant, though having said that the EQ6Pro mount was I think coping reasonably well..I was running a piggyback ED80 on the old OTA for guiding and I was using x 4 counter weights to balance the lot...I'm not sure what the total weight of this was but adding in cameras etc I think it was fairly close to the max.

Since getting the quattro I've swithched to an OAG and so that plus the weight saving on the cf tube I'm back down to 3 weights.

I was a bit worried about colimation on the f4...but so far its been OK ..

It looks sexy too!

Steve

[SimonfromSussex]

That's really good to hear Steve, thank you. I bet it does look good!!!!

I was umming and arring over whether to go CF or not but from what you are saying I think it's probably worth the extra £.

With my C925 I only need two weights and obviously the eq6 handles that fine. I'm not sure I'd want to go up to four weights!!!

You read lots of people cautioning about the colimation so its also good to hear you have found it ok.

Cheers for the reply.

Simon.