M106 secondary arms / an ode to the Smart Histogram

[Menno555]

I am busy with gathering data of M106. I just love the looks and things going on in this galaxy Going to do a RGB + Ha/OIII.
Few days back it was clear but (of course) a 62% moon high in the sky. So I tried with the Optolong L-eNhance filter (Ha, Hb and OIII). And I don't use the Smart Histogram that much but under these circumstances it really can help a lot. And boy, did it ever.

It gave a solution of 536 seconds, Gain 175 and Offset/Brightness 20. Those 536 seconds (almost 9 minutes) were a challenge though with my unguided set-up. But I tried and a new record now for tracking only with my Ioptron CEM25EC mount
Managed to get 25 x 536 sec and much to my surprise I also started to see the secondary arms of M106 (jets of hot gas that are spewed out by the black hole in the center of M106). I am 100% sure that this wouldn't have shown up if I had used my own settings, so I dedicate this to the SharpCap Smart Histogram

All this with a Meade LX200 8" f/10 ACF and a Zwo ASI071MC Pro in Bortle 7/8 skies.
It is a work in progress but here the narrowband data gathered so far, processed roughly.

[timh]

That is really good Menno,

One of my favourite three galaxies. I am impressed with how well that L-enhance filter has done to make the Ha areas obvious and visible. During these occasional clear nights with the moon up I have tended to lay off RGB imaging of the galaxies and just hope that we get some clear dark nights later in the month - but of course you have to take what you are given.

In straight HA you can also easily see the counterpart opposite arm of ionized H as well as the one that you are indicating. I have some pictures with the HA image mixed back into the red channel of the RGB picture in which you can about see both Ha arms. I also found it quite cool since previously I had only become aware of them through looking at and reading about one of the Hubble pictures of the galaxy. The HA arms have the appearance of emerging from the centre but lying flat across the disc (gravity) before curling back out at the ends.

Tim

[Menno555]

Thanks Tim!
Yes, this filter works very well indeed. But aiming to sell it and get the L-Extreme. Did some searching and the L-Extreme looks to be better, especially for my skies. It is more narrow (7nm) and duo with Ha + OIII. I think that the combination with the multiband L-Pro works better.
For this dataset I will capture (way) more with the eNhance but also real RGB (using Baader Neodymium Skyglow filter for contrast): the primary arms are showing now but very faint. I think that's mostly because of the high Bortle here but will see what happens.

Menno

[timh]

Hi Menno,

Below illustrating an alternative approach - adding the HA to an RGB image rather than using a filter to subtract more of the rest of the spectrum and leave the HA behind. It is a powerful approach because it provides a much stronger HA signal but of course requires a mono camera as well.

The RGB frames - adding up to 3h or so - were accumulated gradually over half a dozen or so nights.

SW PDS200 Newtonian , 0.9X SW focal reducer/ flattener, F 4.5, Ioptron CEM70 mount - PHD2 guiding ASI120 mm camera and f ~ 160mm guidescope
Pegasus cube focus controller.

ASI 294 PRO MC camera at - 10 C
ASI 294 PRO MM camera at -10 C plus Optolong 7 nm HA filter

Frames captured in Sharpcap 3.2 and 4.0 and calibrated with matching master flats and darks also captured in Sharpcap (40 frames). No bias

290 X 40s frames at gain 124, 51 x 3 min frames of HA at gain 124. Preprocessed and processed in PixInsight.

The B & W picture is the (nearly) pure HA image obtained by subtracting the red channel of the RGB integrated image from the integrated HA image in an amount such that the stars are (nearly) cancelled out.

This HA only image does quite clearly show M106 with four arms rather than just the usual two as well as locate quite a few spots of high HA signal right out into the outer galaxy arms.

The other two images show the RGB image of the M106 region (with lots of background galaxies) both with and without the HA difference signal added into the red channel. I always think that the final result looks rather like the starship Enterprise wheeling away from a small chasing ship.

[Menno555]

Tim

That looks mighty fine indeed!
When I started a year ago with a color camera, I was told that although that works fine, somewhere in the future I would go for mono.
And I thought "Yeah sure, right" ... but now I understand what people ment

Menno

[timh]

Hi Menno,

An unfortunate fact of this hobby is that there is always more to desire . I am glad though that I didn't just replace one camera with the other because for most purposes the OSC is still my goto . i..e I don't see me bothering with an RGBL filter wheel for the mono because (imo) the OSC covers that space perfectly well while the mono enables L plus all the narrowband stuff.

TimH