M101 - Pinwheel Galaxy - WO Z73 AA183M

[Han Solo]

Hi,

This is my first real post and first real attempt at a galaxy. Up until now I have been experimenting with my equipment and particularly with my AA Hypercam 183M PRO TEC camera and trying to figure out gain and exposure lengths to try to minimise noise and the dreaded amp glow. I also know that I have not quite got the camera spacing right as I'm seeing some elongated stars around the image perimeter. Anyway I would really appreciate your feedback with this image. It is Luminance only. This is light frames only, I still have to capture darks, flats, bias etc...

• Capture Date - 25/04/2019
• 114 x 60s subs @ gain_100
• Stacked in DDS and processed in Photoshop

Equipment:

• William Optics Zenithstar 73
• Altair Hypercam 183M PRO TEC
• Skywatcher HEQ5 with belt mod
• TS Optics 60mm guide scope
• Altair GPCAM2 290M

 

Thanks for looking, James

 

[AKB]

Looks like a pretty darn good image of M101 to me!

[Star101]

Looks good to me too.

As you say, no darks applied . When you do, as long as you have DARKS at the same temperature and gain then Amp Glow should not be a problem. 

Not bad image for starters. 

Well done.

[Han Solo]

Thank you for your kind words, I’m really pleased with this so far and it amazes me how much detail can be pulled out of the data since the histogram was so far to the left it was unbelievable. 

I’m struggling to accept that all the data is contained within the left quadrant of the histogram as it goes against all my previous photographic experience (expose to the right). At lease noise is better under control in these subs over higher gain and longer exposure times with a more centralised data histogram.

Yes, my task for this evening is to capture the DARKS, FLATS & BIAS subs. Being the TEC version of the camera I shouldn’t have any difficulty in capturing these. I don’t know how people capture their DARKS at the time of shooting their LIGHTS. By the time my LIGHTS were finished I was ready for bed with work the next day. Obviously the camera is still on the telescope for the FLATS. I’ll post an updated ‘final’ image this evening.

Edited April 26, 2019 by Han Solo

[Han Solo]

Updated image processed with calibration frames. The background still has a bit of a gradient and amp glow which I’m struggling to get rid of. But it is much better with the calibration frames.

thoughts?

 

 

[tomato]

That’s a fine image, it’s way ahead of what I achieved imaging first time with a dedicated cooled Astro camera. I’m not sure if I have missed what level of dark sky you are imaging from but that level of noise in the background looks pretty usual to me for a couple of hours integration time for a Bortle 4/5 sky quality.

[Han Solo]

8 minutes ago, tomato said:

That’s a fine image, it’s way ahead of what I achieved imaging first time with a dedicated cooled Astro camera. I’m not sure if I have missed what level of dark sky you are imaging from but that level of noise in the background looks pretty usual to me for a couple of hours integration time for a Bortle 4/5 sky quality.

Hi tomato,

thank you very much for you encouragement. I live in a Bortle 5 location. I haven’t used a light pollution filter yet, do you think that will help with the noise levels?

James

[JeremyS]

Lovely images!

[tomato]

10 hours ago, Han Solo said:

Hi tomato,

thank you very much for you encouragement. I live in a Bortle 5 location. I haven’t used a light pollution filter yet, do you think that will help with the noise levels?

James

Hi James

I live in a Bortle 4 location and I rely on the software (APP and Startools) to deal with the light pollution, you can see the routines making a noticeable improvement to the background when applied. There are plug-ins available (e.g. Gradient Exterminator?) for Photoshop that will do the same job.

Steve

[FaDG]

11 hours ago, Han Solo said:

I haven’t used a light pollution filter yet, do you think that will help with the noise levels?

For galaxies and clusters not so much,  be happy with your Bortle 5 sky! 

It may help for nebulae, as it removes some of the light pollution letting the real signal pass undisturbed. 

Fabio

[FranckiM06]

It is very nice image but I prefer the first image. The last one, background is too dark and you erased most of details in the extensions ! 

Franck

[Adam J]

On 26/04/2019 at 21:33, Han Solo said:

Updated image processed with calibration frames. The background still has a bit of a gradient and amp glow which I’m struggling to get rid of. But it is much better with the calibration frames.

thoughts?

 

 

Not sure which calibration frames / which software you are using to stack, but some software has specific code to address the amp glow in the 183 and other software lacks this. APP for example has this feature.

[Han Solo]

18 hours ago, Adam J said:

Not sure which calibration frames / which software you are using to stack, but some software has specific code to address the amp glow in the 183 and other software lacks this. APP for example has this feature.

Hi Adam J,

i am using deep sky stacker at the moment and then processing in photoshop. When I took my Dark frames I didn’t take them in a dark room which I read may case issue with light leaking into the camera body. I’ll try again with a different set of darks. I will also look into the 183 amp glow code thing and see if deep sky stacker has it, otherwise I will look into APP as an option. Thank you for the info.

[Han Solo]

On 28/04/2019 at 00:49, FranckiM06 said:

It is very nice image but I prefer the first image. The last one, background is too dark and you erased most of details in the extensions ! 

Franck

Hi Franck,

Yes I agree, these were just quick processes and I think there is more detail in the data, however I'm not very proficient yet  Thank you for your feedback, its things like this which will help me to improve.

James