trifid nebula Re-processed - Trifid Nebula in Sagittarius ( Messier 20, NGC 6514 ) - new PhotometricColorCalibration tool
Recently Browsing 0 members
No registered users viewing this page.
Spent the last three nights imaging these three objects. Managed to get them all in the same frame of my ES 102mm FCD100 scope. Pretty happy with how it turned out. I would have liked to have grabbed a little more SII data. When I originally captured it, I thought I might only have two clear nights, so I imaged it as HA/OIII. Turns out there's almost no OIII. On the third night, clouds were supposed to roll in about 4am, cutting the imaging session short, but it stayed clear the whole night, and I got a full night of data with the exception that I got a late start due to technical issues when I first started imaging.
The ASI1600's halos are rearing their ugly heads on the two brightest stars. I tried to tone them down some by desaturating the colors around both stars...it worked a bit.
Another 15 hours and I could probably get rid of any remaining grain, but just don't have the clear nights to get it done. 15.8 hours total imaging time.
Celestron CGX Explore Scientific 102mm FCD100 ZWO ASI1600MM-C ZWO Filter Wheel with Astrodon 5nm filters ZWO ASI290MM Mini guide camera Stellarvue F50G guide scope
This is the first image i post here.
It has been taken in August/September from my backyard. It is one of my first image taken with my new Moravian G4-16000 CCD camera.
Taken with my TeleVue NP101is modified with a new focuser :
Modifications can be viewed here : http://www.poigetdigitalpics.com/photo-equipment3.html
SH2-171 in LHa - R(ha)GB :
Full resolution image in 4k x 4k at this link : http://www.poigetdigitalpics.com/G4-16000/sh2-171 New Version.htm
I've been spending some time processing over cloudy christmas and realised the thing I find most daunting, difficult and annoying is creating star masks. So my question is - is there a way of creating star masks (in Pixinsight preferably, but open to other ways!) which is (a) always accurate (b) relatively quick (c) repeatable?
I've worked through LVA tutorials and looked at David Ault's technique. I also have the Bracken book to go through. Main techniques seem to be:
1. Stretch extracted lightness, clip low, bring down highlights, then use Star Mask process - very inconsistent results I get with this approach
2. Similar to above, but use MMT/MLT to remove nebulosity to create support image, then use different star scale Star Masks to capture all stars and then use pixelmath to put them all onto one image - very time consuming I find, also lots of noise setting fiddling
I am very interested to see how people go about this and whether there are any neat tips and tricks to help the process! Thanks!
The Great Barred Spiral Galaxy ( NGC 1365 ) in the Constellation Fornax
( edit - star chart added )
The Great Barred Spiral Galaxy ( NGC 1365 ) - Chart ( please click/tap on image see larger and sharper version )
A full size ( 6200 x 4407px ) image can be downloaded from here.
Below the equator, not seen from much of the Northern hemisphere, NGC 1365 passes very nearly directly overhead an observer situated near Cape Town, as Sir John Herschel was in November of 1837 when he discovered this “remarkable nebula” that is numbered 2552 in his book of observations from the Cape.
Not called a “nebula” now, of course, this striking object is one of the nearest and most studied examples of a barred spiral ( SB ) galaxy that also has an active galactic nuclei resulting in its designation as a Seyfert galaxy.
At around 60 M light years from Earth, NGC 1365 is still seen to occupy a relatively large area ( 12 by 6 arc minutes ) due to its great size; at some 200,000 light years or so across, NGC 1365 is nearly twice as wide as the Milky Way and considerably wider than both the Sculptor and Andromeda galaxies.
This High Dynamic Range ( HDR ) image is built up from multiple exposures ranging from 4 to 240 seconds with the aim of capturing the faint detail in the spiral arms of the galaxy whilst also retaining colour in the brightest star ( the orange-red 7th magnitude giant, HD 22425 ). Also, scattered throughout the image, and somewhat more difficult to see, are numerous and far more distant galaxies.
The Great Barred Spiral Galaxy
New General Catalogue - NGC 1365
General Catalogue - GC 731
John Herschel ( Cape of Good Hope ) # 2552 - Nov 28, 29 1837
Principal Galaxy Catlogue - PCG 13179
RA (2000.0) 3h 33m 37.2 s
DEC (2000.0) -36 deg 8' 36.5"
10th magnitude Seyfert-type galaxy in the Fornaux cluster of galaxies
200 Kly diameter
60 Mly distance
Telescope: Orion Optics CT12 Newtonian ( mirror 300mm, fl 1200mm, f4 ).
Corrector: ASA 2" Coma Corrector Quattro 1.175x.
Effective Focal Length / Aperture : 1375mm f4.7
Mount: Skywatcher EQ8
Guiding: TSOAG9 Off-Axis-Guider, Starlight Xpress Lodestar X2, PHD2
Nikon D5300 (unmodified) (sensor 23.5 x 15.6mm, 6016x4016 3.9um pixels)
Blue Mountains, Australia
Moderate light pollution ( pale green zone on darksitefinder.com map )
Capture ( 3, 7 & 8 Dec 2018 )
7 sets of sub-images with exposure duration for each set doubling ( 4s to 240s ) all at unity gain ( ISO 250).
140 x 240s + 10 each @ 4s to 120s
total around 9.7 hrs
Processing ( Pixinsight )
Calibration: master bias, master flat , master dark
Integration in 7 sets
Image Plate Solution
Resolution ........ 0.586 arcsec/px ( full size image )
Rotation .......... -0.003 deg ( North is up )
Field of view ..... 58' 37" x 38' 55"
Image center ...... RA: 03 33 36 Dec: -36 08 27