Needle Galaxy and NGC 4562

[umasscrew39]

Finally got my new desktop to process the ASI2600 frames.

• 3 hours total integration
  120s subs
  L-Pro filter
  C11" EdgeHD @ f/7

  

  Needle Galaxy_2.jpg (196.09 KiB) Viewed 2103 times

[turfpit]

Cool ...

Dave

[Menno555]

It was already on my to-do list ... but now even more
Great capture

[oopfan]

Hi Bruce,

Very nice!

Can you run a quick check for me? If you saved individual frames, can you sample your sky background with FITS Liberator (or whatever software is convenient)?

Thanks,
Brian

[umasscrew39]

Thanks much gents. I may reprocess this as this was a quickie as I was just so anxious to try the new computer last night. I think I can get it better.

Brian- I did save individual fits frames but not sure how to get the info you want. Can you explain more?

Bruce

[oopfan]

Sure, I regularly use three programs: FITS Liberator, Siril, and KStars. They are all free. Do you have one of them installed?

The default action when you open a FITS file with either FITS Liberator or KStars is by giving you a cursor that you hover over the image. A readout of ADU counts is given. Opening a file with Siril requires you to draw a selection box on a part of the image devoid of stars and nebulae, then you right-click and select "Statistics". You want the "Mean" value. FITS Liberator and KStars don't allow you to draw a selection box so I recommend computing the mean pixel value in your head as you move the cursor back and forth across a dark portion of your image. Don't worry about accuracy.

Brian

[umasscrew39]

Hi Brian

Sorry but I am totally lost. I have FITS Liberator 3 and opened it up. No cursor- just the hand tool and when I hover it over the image behind the grid nothing happens. Only see the image RA and DEC px values changing.

[oopfan]

Great! Do you see something like this?

FITS Lib.jpg (10.89 KiB) Viewed 2078 times

Swirl your cursor around an area on the image that is devoid of stars. Watch the readout that I highlighted in red. What is the average value? No precision required.

Thanks,
Brian

[umasscrew39]

ahh....OK

Number fluctuates in the low 500s (e.g., 510-540)

[oopfan]

Wow that is impressively low for a 120s exposure at f/7. Do you know your Bortle class?

Brian

PS:

Ah, I see your L-Pro filter is cutting out a lot of the light pollution. Never mind!

https://www.highpointscientific.com/opt ... d-lpro-200

Do you have issues with color balancing?