Central region of M31 from before DSC

[RobertM]

I grabbed this just after the Crescent but only just got around to processing it.

Sky 90@f/4.5 unguided with SXV-H9 binned 1x1, 10 x 60s Astronomik Luminance filter.



Robert

[Fay]

I really like that, Robert, lot of good rabbits coming out of the hat today! Just nice.

[Daniel]

Lovely image, those stars are nice and round for 60s unguided and so nice to see M31 coming round again, I did a test shot of it a few nights ago myself through the SCT at F10, so only really got the core, but was great to get some of those brown dust lanes coming through with the Ha mod on the camera finally.

Does anyone know how to bring out that blue-ish bit around the edge I always see on the professional astro photo's?

[MarkS]

Another great image - I'm amazed at the detail you can get with just 10min of data.  I suppose that's due to imaging at F4.5 with a decent cooled camera ...

[Rocket Pooch]

was that before the collimation was fixed?

[RobertM]

Yes Chris, before the collimation was fixed, the stars have the same flare towards the bottom right as in the NGC6888 image. I only sorted it out on Saturday and there's been no chance to get out since.

About 60s was all I could do without maxing out on the core but it needs slightly longer for the arms.  I think it's quite a tricky target to get spot on and having a small ccd chip doesn't help because of the size.  I was thinking of a mosaic but to do it properly will require a minimum of 4-6 frames of each LRGB+Ha each of 60 mins = 20-30 hours of imaging - that's probably all the clear nights of autumn with current weather patterns

[Mike]

Great image Robert.

[Carole]

Lovely image Robert.
Well done.

Carole

[Rocket Pooch]

what was the adu reading of the core?

[RobertM]

ADU of the core was 57000

[Rocket Pooch]

ok, can you e-mail me to stacked sub FITS file, I'll use an AIP feature on it....

[RobertM]

sent...

[Rocket Pooch]

Hi,

This is one I took last year, with 16x4 minute subs, there's less noise because of the number of subs.  and yes I need to get some imaging in, I know, maybe in a few weeks time.

[Fay]

Chris, stop showing off!

[Rocket Pooch]

No I'm not, but John did point out I keep forgetting to post my processed images, like this:



But seriously, I have learned more about processing this year than last because of the weather so some of my old images seem better now.

[Fay]

Your'e getting cheeky!!!!! You know it is fantastic, a take your breath away moment.

[Rocket Pooch]

yes but I only seem to et 3 sessions like that a year, how anoying, maybe its time to buy a house in France.

[MarkS]

That's a stunning image Chris.

[RobertM]

None too shabby Chris - it's certainly thrown the gauntlet down for M31.  I assume it was with the HX916 ?

[Mike]

Great processing. Lovely detail.

[Rocket Pooch]

yes it was with the HX916 and ED80 last year from france, this year I would like to do a nice M33, M45 and also some dark nebula, but it needs to be clear when we get there.

[Mike]

There are loads of dark nebula out there that are very rarely imaged. Those two Observing Officers books I have lists hundreds of them and there are loads that would make interesting, if challenging, subjects.

[RobertM]

Mike, are those your books or the societys ?  I want to get myself a book that shows deep sky objects so I could plan observing sessions - any recommendations ?

[Fay]

I was testing last night. I got AstroArt to work guiding with SX but while the bubbles kept in the centre for a while, they suddenly went walkabout. I will have to read up a bit more on the settings, unless you have any tips, Chris.
The trouble with using the SX for guiding was, too many stars. It was difficult to not include other stars in the guiding rectangle.


I changed to PHD & modified webcam & it was easy to do......last night.

I flitted about, as I knew sky would not be good enough for an image. I did 4 min of M31, but centre really blown out. How did you keep your core in check, Chris?
Mark, I cannot work out how you got such a good Eagle when your guide star warning went off so many times  because of cloud. I always stop the guiding when this happens.

[Mike]

Mike, are those your books or the societys ?  I want to get myself a book that shows deep sky objects so I could plan observing sessions - any recommendations ?

They belong to the society. They are really good. There are two books and here are the details - http://www.willbell.com/HANDBOOK/nitesky.htm

[MarkS]

Fay,

If PhD loses the guide star for a few seconds at a time, it is not a disaster.  The mount will continue to track the sky as normal and when the guide star is "found" again, the guiding software will send the mount any small correction pulse it needs to bring it bang on target again.  The resulting subs are usually quite usable, as you noticed from my Eagle.

Talking about guiding, I've realised I probably need a longer focal length guidescope.  As an example, a 0.5 pixel guiding error in my 300mm guidescope translates into a 3 pixel error for the 1800mm imaging scope.   So I'm going to experiment with a 2x teleconverter on my 300mm telephoto lens which will give me 600mm focal length but, unfortunately, will also reduce me to an aperture of  F9 instead of F4.5

Mark

[Rocket Pooch]

I was testing last night. I got AstroArt to work guiding with SX but while the bubbles kept in the centre for a while, they suddenly went walkabout. I will have to read up a bit more on the settings, unless you have any tips, Chris.
The trouble with using the SX for guiding was, too many stars. It was difficult to not include other stars in the guiding rectangle.


I changed to PHD & modified webcam & it was easy to do......last night.

I flitted about, as I knew sky would not be good enough for an image. I did 4 min of M31, but centre really blown out. How did you keep your core in check, Chris?
Mark, I cannot work out how you got such a good Eagle when your guide star warning went off so many times  because of cloud. I always stop the guiding when this happens.

Fay,

You need to increase the telescope speed, its overcorrecting at the moment, also you might need to SWAP the XY.

Chris

[Fay]

Thanks Chris. As I alter these things, can you see the difference straight away, or do you have to wait a while for new instructions take effect?

[RobertM]

Mike, any chance I could borrow both of those books for a couple of weeks ?

[Mike]

As long as they are brought back by the next observing session on the 26th August that will be fine.

[RobertM]

Thanks Mike, when could I pick them up ?

[Rocket Pooch]

Thanks Chris. As I alter these things, can you see the difference straight away, or do you have to wait a while for new instructions take effect?

Yes a minute or so, but if the corrections are still too large you increase the value again, what you should end up with is the star being about the centre third of the 1 pixel ring, then your ok, if the guiding is reporting .20 in RA and DEC you should be ok.

Chris

[Fay]

Thanks Chris. I have been using the simulator today to get familiar with it

[Rocket Pooch]

if you can crack that then you will be able to use your sxd for guiding ok, but bin the camera 2x2