M27 Narrowband

4 years 1 month ago - 4 years 1 month ago #104741 by Bruno
M27 Narrowband was created by Bruno
Got this last Saturday night.

It is a narrowband image using Ha, O111 and S11 filters and combining both HOS and SHO palette images together in Photoshop. Image captured with SX-H16 CCD camera on a Celestron 11" telescope. Combined exposures 2.5hrs. Used 0.63 reducer and OAG guiding with Lodestar camera.

John

www.flickr.com/photos/89666413@N04/21035...m-72157632096781703/

John
IAS

We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard, because that goal will serve to organize and measure the best of our energies and skills
The following user(s) said Thank You: dave_lillis, johnomahony, Kinch

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4 years 1 month ago #104743 by michael_murphy
Replied by michael_murphy on topic M27 Narrowband
Hi John,

I got a 404 on the link.

Michael.

IFAS Chairperson.

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4 years 1 month ago - 4 years 1 month ago #104745 by Bruno
Replied by Bruno on topic M27 Narrowband
Sorry Michael, I changed permissions try again
Thanks
John

www.flickr.com/photos/89666413@N04/21035...m-72157632096781703/

John
IAS

We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard, because that goal will serve to organize and measure the best of our energies and skills
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4 years 1 month ago - 4 years 1 month ago #104747 by Kinch
Replied by Kinch on topic M27 Narrowband
Hi John,

I am sure you had great fun with the narrow band. One can put things together any which way to make a picture that pleases. Just wondering though about HOS and SHO combined. I must admit I have never tried that.

Did you try HSHO? That is what I use a lot now.

At that focal length tracking and focus are always going to be critical and indeed difficult - so you did a great job. How long did you do on the subs? Do you have to refocus between subs? For me, I use 20 min subs and generally (not always) have to refocus between each shot.....but that is with a refractor.

Is this a crop of the full image or is this the real FoV? (I am not sure what your combination will give exactly).

Hope to hear more details from you......

Brendan.

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4 years 1 month ago #104778 by Bruno
Replied by Bruno on topic M27 Narrowband
Yes Brendan, I had great fun with the different combinations. My problem was that I did not get enough S11 data and I need to get more as soon as the sky cooperates. At present there is 15 X 600sec subs. I focused using FWHM checking with MaximDL and a lakeside focuser. I think you are right to keep checking focus. I did not focus between each shot but it held fairly stable throughout the evening. The carbon fibre tube probably helped.

The Image is cropped from 2048X2048 to 1883X1455 to get rid of some residual vignette and improve framing. The FOV before cropping was 29 X 29 arc min and the image scale is 0.86 arcsec/pixel.

When I get more S11, I will do a HSHO and have some more fun.

John

John
IAS

We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard, because that goal will serve to organize and measure the best of our energies and skills

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4 years 1 month ago #104781 by Kinch
Replied by Kinch on topic M27 Narrowband
Hi John,

With the Carbon Fibre tube you are most definitely at an advantage over me on having to re-focus or not. The Tak that I use is renowned for having to be continuously refocused through the night.


On the guiding (at 0.86 arcsec/pixel) you have a job there on long (NB) exposures. I use PHD2 (free) - what are you using? (It works in tandem with Sequence Generator Pro - which is my capture programme).

Brendan.

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4 years 1 month ago #104789 by Bruno
Replied by Bruno on topic M27 Narrowband
Brendan, the benefits of a Tak like yours would more than compensate for any refocus issues :-) Some day Santa might be good to me. I think your attention to focusing applies to any scope and I should give it even more attention particularly between long exposure shots and filter changes.

I use MaximDL for capture and for guiding and find it does the guiding job well. I use a Losmandy G11 mount and a Lodestar original guide camera in an OAG set up. I have used PHD and had no complaints apart from usual guiding frustrations until you get the settings adjusted for the conditions. Whenever I use it I find that the dithering routine works well with Maxim.

John

John
IAS

We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard, because that goal will serve to organize and measure the best of our energies and skills
The following user(s) said Thank You: Kinch

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