Tonight there was the opportunity for a full nights imaging again. I have quite a lot of data of Flaming Star and Horsehead gathered over the last couple of Months so wanted something a different target and something to give an easy feel good image! Off to our neighbouring galaxy Andromeda then, never fails to impress. I’ve selected to start the night with M31 Andromeda Galaxy, followed by M45 Pleiades for the majority of the night.
One thing to mention, I’ve left the l-Enhance filter in place, although both of these targets are really Wideband I have seen some good images using this filter of both of these subjects, admittedly in the case of M31 to add to unfiltered already collected data but I thought what the hell.
Another change tonight is I have dropped down from 1600 ISO to 800 ISO. Decided on this approach as I have obtained some figures that appear to show the sweet spot in terms of unity gain is 800. I am also hoping with less sensitivity I am hoping gives me more dynamic range, therefore I have extended the exposures from 120 seconds to 300 seconds, probably finally stretching the legs of my HEQ5 mount and guiding set up.
I took Darks before the nights imaging session at dusk, consequently there is not an accurate match on temperature. Darks are about 2-3 degrees warmer than the Lights, during the nights imaging we got to -2.
One issue that I note here to aide my own memory, is that I automated both captures in NINA with a Slew and Rotate – I really wanted to try and get a specific framing of both objects. Unfortunately this means tomorrow when I do my flats I will only be able to use Flats with the last target as the rotation change between targets mean any dust spots in the optical path that Flats are designed to remove will not be aligned to the first target, Live and learn!
I am trying to offset this by use of dithering – I am dithering every 2 of my 5 minute exposures.
M45 Capturing in N.I.N.A
Results
M31 – Andromeda Galaxy
It so high in my sky right now early in the evening it was just too good an opportunity to miss. Ideally especially with such a minor phase of Moon I should have removed the l-enhance filter, but I decided that I did not want to take the image train apart (being a little lazy) and have any issues with autofocus etc in N.I.N.A. so lets say I am experimenting here.
29 5m Subs totalling 2h25m integration time, I used a master Bias for ISO 800 I collected only a few months ago, I also captured 12 5m Darks for a total of 1h of Dark Integration. As mentioned above No Flats! Due to the Flats only being appropriate for the M45 imaging session because of the Rotation.
M31 – Andromeda, Stacked and stretched
The following starless version was created after passing the stretched image above through Starnet++.
M31 Starless
Generating a Star mask based on selecting the highlights of the Stacked and Stretched image and then controlling the opacity of this new star layer on the Starless image to control the star bloat. My final image is as follows:-
M31 Final
I am pleased overall with this image, as a reminder this is taken with the l-enhance filter which is really designed for Emission Nebula not wideband objects such as Andromeda. I think you can see the effect on this by the more conspicuous Hydrogen areas (shown as the speckled red areas in the galaxy lanes). I have seen other Astrophotographer combine this sort of image with a wide field image to bring out these red areas.
Also No Flats available so there is definitely some room for addition data without the filter on a moonless dark night, flats on the next trip out to Andromeda!
M45 – Pleiades
Second image of the night gave me 5h 16m after a few images were rejected. Along with these 63 5 minute subs, I have 30 flats and 12 5m Darks. ISO 800 used throughout.
M45 Final
The framing and rotation of this was deliberate, I’m an avid follower of Nico Carver (NebulaPhotos) and his youtube channel. I saw his framing of this subject which I thought was a more artistic shot that the usual Pleiades shots I have seen. This is not in the same league, a darker sky, less moon and removal of the -Enhance filter would improve.
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