M27 Dumbbell Nebula, Vixen 81s + Altair 183C

A place to share images that you have taken with SharpCap.
Forum rules
Please upload large images to photo sharing sites (flickr, etc) rather than trying to upload them as forum attachments.

Please share the equipment used and if possible camera settings to help others.
Post Reply
User avatar
turfpit
Posts: 869
Joined: Mon Feb 13, 2017 8:13 pm
Location: UK
Contact:

M27 Dumbbell Nebula, Vixen 81s + Altair 183C

Post by turfpit » Sun Jun 30, 2019 12:41 am

Living at 53°N, this image was captured when there was no astronomical darkness. The 1h 40m capture of lights took place between 00:40 and 02:20 on 29th June 2019. High res image here https://www.astrobin.com/full/412451/0/.

_M27-100x60s-.jpg
_M27-100x60s-.jpg (245.75 KiB) Viewed 545 times

Equipment: Celestron AVX, Vixen 81s, Altair 183C, Altair 1.0x flattener.
Preparation: 2 alignment + 4 calibration stars + All Star Polar Align. A Bahtinov Mask was used for focus.
Software: SharpCap, FITS Liberator, SiriL, GIMP.
Capture: RAW12, Black Level 30, Gain 200, Exposure 60s, unguided. Bortle 6 site.
Data: lights 100x60s, darks 60, bias 100, flats 100.
Processing: SiriL was used to calibrate, register and stack (best 90% based on FWHM) the frames and carry out crop, background extraction, colour calibration, colour saturation, remove green noise & histogram transformation. Minor edits and colour balance carried out in GIMP.
FITS Liberator was used to check that a bias frame at gain 200 & black level setting of 30 had a centralised histogram plus test frames to establish the exposure setting gave a reasonable histogram for capture.

M27-lights_00000.CameraSettings.txt
(568 Bytes) Downloaded 23 times
Dave

User avatar
turfpit
Posts: 869
Joined: Mon Feb 13, 2017 8:13 pm
Location: UK
Contact:

Re: M27 Dumbbell Nebula, Vixen 81s + Altair 183C

Post by turfpit » Sun Jun 30, 2019 12:48 am

The following screenshots demonstrate the preparation and capture steps I used for the M27 image. Hopefully these will prove useful to others.
Dave

1-focus-with-bahtinov-mask.JPG
1-focus-with-bahtinov-mask.JPG (51.24 KiB) Viewed 542 times

2-check-black-level-setting-for-gain200.JPG
2-check-black-level-setting-for-gain200.JPG (64.92 KiB) Viewed 542 times

3-test-frame-60s-exposure.JPG
3-test-frame-60s-exposure.JPG (58 KiB) Viewed 542 times

4-ready-to-capture.JPG
4-ready-to-capture.JPG (61.77 KiB) Viewed 542 times

5-capture-in-progress.JPG
5-capture-in-progress.JPG (56.87 KiB) Viewed 542 times

6-after-100-frames.JPG
6-after-100-frames.JPG (58.67 KiB) Viewed 542 times

7-dark-frame-capture.JPG
7-dark-frame-capture.JPG (54.29 KiB) Viewed 542 times

8-flat-frame-capture.JPG
8-flat-frame-capture.JPG (56.88 KiB) Viewed 542 times

User avatar
turfpit
Posts: 869
Joined: Mon Feb 13, 2017 8:13 pm
Location: UK
Contact:

Re: M27 Dumbbell Nebula, Vixen 81s + Altair 183C

Post by turfpit » Sun Jun 30, 2019 12:52 am

The following screenshots demonstrate the processing steps I used after the M27 capture. Hopefully these will prove useful to others.
Dave

9a-stack-loaded-in-Siril.JPG
9a-stack-loaded-in-Siril.JPG (59.62 KiB) Viewed 541 times

9b-M27-before-background-extraction.JPG
9b-M27-before-background-extraction.JPG (136.87 KiB) Viewed 541 times

9c-M27-after-background-extraction.JPG
9c-M27-after-background-extraction.JPG (135.02 KiB) Viewed 541 times

9d-after-colour-calibration.JPG
9d-after-colour-calibration.JPG (57.96 KiB) Viewed 541 times

9d-after-colour-calibration.JPG
9d-after-colour-calibration.JPG (57.96 KiB) Viewed 541 times

9e-after-green-noise-removal.JPG
9e-after-green-noise-removal.JPG (59.54 KiB) Viewed 541 times

User avatar
turfpit
Posts: 869
Joined: Mon Feb 13, 2017 8:13 pm
Location: UK
Contact:

Re: M27 Dumbbell Nebula, Vixen 81s + Altair 183C

Post by turfpit » Sun Jun 30, 2019 10:41 am

I was looking at the file store impact for this project.
  • A single RAW12 frame at 5440x3648 is 38Mb.
  • 100 lights + 100 flats + 100 bias + 60 darks = 360 images
  • 360 x 38Mb = 13,680Mb or ~13Gb
  • once the calibration frames are applied and debayered there are an additional 100 x 116Mb files
  • registration creates another 100 X 116Mb files
  • calibration + registration creates 200 x 116Mb = 23,000Mb or ~ 23Gb
  • the final processing folder totalled ~40Gb
In just under 3 hours of capture, ~13Gb of data was generated. The final processing folder was ~40Gb.

Dave

User avatar
turfpit
Posts: 869
Joined: Mon Feb 13, 2017 8:13 pm
Location: UK
Contact:

Re: M27 Dumbbell Nebula, Vixen 81s + Altair 183C

Post by turfpit » Mon Jul 01, 2019 11:41 am

I was looking back over my old images and found these M27 shots from November 2016, when I was just starting out. Things are moving in the right direction :D , Bahtinov mask - best 20 quid I ever spent :lol:

M27-1.jpg
M27-1.jpg (27.45 KiB) Viewed 497 times

M27 Dumbbell Nebula.PNG
M27 Dumbbell Nebula.PNG (116.63 KiB) Viewed 497 times

Dave

nexusjeep
Posts: 153
Joined: Thu Oct 18, 2018 3:01 pm

Re: M27 Dumbbell Nebula, Vixen 81s + Altair 183C

Post by nexusjeep » Tue Jul 02, 2019 9:11 am

Hi Dave,
Good shot I hate this time of year due to the non existent sunrise / sunset good image though I might have to get out and have a go at something using narrowband it's just so late in the evening / morning before you can potentially start capturing. So have been spending my time modifying the observatory, focuser, etc instead ready for mid August when things should start to improve. Sad that I now look forward to summer passing so that we get back to shorter days.

Cheers
Nick

User avatar
turfpit
Posts: 869
Joined: Mon Feb 13, 2017 8:13 pm
Location: UK
Contact:

Re: M27 Dumbbell Nebula, Vixen 81s + Altair 183C

Post by turfpit » Tue Jul 02, 2019 3:54 pm

Thanks Nick.

At the moment, my 'darkness' is from 00:15 - 02:15, hence the 1h 40m capture with a one shot colour camera. Don't forget the moon, this viewtopic.php?f=16&t=1693 was shot in daylight.

Dave

Post Reply

Who is online

Users browsing this forum: No registered users and 1 guest