This so far is the most illusive: the Ursa Minor Dwarf galaxy (UGC 9749, PGC 54074). In the full version here https://i.ibb.co/8Dxtn4W/ursa-minor-dwarf.jpg it's shown as a bit more dense with stars in the centre.
Not a spectacular capture, yet for me it is
Due to the virtually absent surface brightness, this galaxy was only discovered in 1955 during the Palomar Sky Survey. It is a satellite galaxy of our Milky Way and is located about 215,000 light-years away.
It was explored with the Hubble in 1999 and the galaxy is around the same age as the Milky Way. It originated in the typical way of this type of system where the star formation of all stars took place at the same time. This happened about 14 billion years ago and lasted about 2 billion years.
Since there has been virtually no active star formation since then, there is also no gas and dust present, which explains the virtually absent surface brightness.
A total of 5 hours of data and more data is not really useful. The Bortle 6/7 is making that kinda impossible. I have tried recordings of 600 sec, but that only works with narrowband recordings.
Noise reduction was useless since the the tiny stars also disappeared and they give that little bit of shape to what is there.
However, the colors have been strengthened as an extra indication and for the rest I had to stretch quite a bit.
But it is visible (kind of) so mission accomplished
Also, it is more visible on monitors than on mobile devices.
Over at astroforum.nl there was some discussion how to "proof" that I captured it and not stars of the Milkyway, that it wasn't a kind of wishful thinking.
Someone took my capture and made a "heatmap" of it and that shows indeed the exact place of the most dense part of the galaxy.
- Surface_Plot_of_ursa-minor-dwarf_FFcor_1pxMedian_Max_Mean_dens.jpg (270.72 KiB) Viewed 1831 times
It is consistent with my own in indication I made.
- ursa-minor-dwarf-outline-sm.jpg (99.17 KiB) Viewed 1831 times
And this is the full capture. Most of the bright(er) stars are part of the Milkyway. The stars of the UMi Dwarf here in my capture are ranging between MAG 17 and MAG 21. For a bit bigger version, see the link at the start of this topic.
Bortle 6/7
Meade LX200 8" f/10 ACF OTA
Ioptron CEM25EC mount (no guiding)
Baader Neydymium Skyglow filter
Zwo ASI071MC Pro camera
Captured with SharpCap Pro @ -10 Celsius / White balance R50 B50
60 x 300sec / Gain 90 / Offset 4
20 x darks, 50 x flats and 50 x dark flats
Stacked with DeepSkyStacker
Edited with Siril and Photoshop
Siril: Background Extraction and Histogram
Photoshop: Curves, Levels, Camera Raw Filter (blacks, color saturation, clarity, sharpening)
