M65-66, Arp 16-317

[jthommes]

Here is an image of a Messier spiral pair, M65 and M66. The galaxy M66 is one of a few objects that gets two Arp designations. One is Arp 16 (detached segments class, "Large concentration at end of S arm"); and one is Arp 317 (groups of galaxies class, The Leo Triplet along with M65 and NGC 3628). One can see the southern arm M66/Arp16 has an asymmetric concentration; but I also see that M66 has a faint extended northern arm.

This image field also has several background galaxies that are all at a fairly large distance and three quasars with significant redshift. The quasar SDSS J112045.15+130405.2 has a redshift of 1.6950 with a light travel time of 9.835 billion light years. M66 and M65 distance estimates (by redshift estimate) are 48 and 53 million light years, respectively. Redshift independent estimates are a bit less at 30.6 and 40.3 million light years.

Image and details can be accessed at the link below (or by clicking on the M65 and M66 thumbnail crop below). The annotated image (which shows many of the galaxies and info) also has a link below but it can also be accessed from the main image webpage as well. Full size image can also be accessed from the image webpage and has an image scale of 0.58 arcsec/pixel.

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    M65 and M66, Arp 16

Annotated Image:
M65 and M66, Arp 16 Annotated

Scope: Celestron 9.25 Edge HD 235 mm at f/7
Camera: ASI294MM (Baader L RGB filters)
Location: DAA Observatory, Shelter Valley, CA

[Juno16]

Wow, what a beautiful image Jim!

The quasars are resolved very well!

As always, the annotated version is much appreciated!

[helicon]

Great image Jim!

[messier 111]

really nice image , thx .

[Jockinireland]

Fantastic image Jim. Can I ask how you are annotating - in Pixinsight? If so, what catalogue do you use to show up the Quasars as you have done - with light travel time. I've tried using a using a txt file downloaded from the Pixinsight forum as a custom catalog and while it works and indeed shows up the quasars (as below) it gives only minimal information. Also, how do you get the distances on those PGC galaxies.

Thanks for your help.

David.

[MariusD69]

Amazing image! Very well done, Jim!!

[Gordon]

Congratulations Jim on having your image selected as todays TSS APOD!!


app.php/article/5-17-2021-tss-astrophot ... of-the-day

[helicon]

Congrats Jim on winning the APOD for today!

[Makuser]

Hello Jim. A beautiful image of M65 and M66. Nice cores, dark dust lanes, and sparkly spiral arm details on these galaxies. Thanks for putting up this wonderful capture Jim, and congratulations on winning the TSS APOD Award today.

[Thefatkitty]

Well deserved APOD Jim; that is fantastic! As well, the info is appreciated too

All the best,

[Graeme1858]

Nice Leo doublet Jim. And thanks for the quasar information.

Congratulations on the APOD.

Regards

Graeme

[STEVE333]

Very nice internal details and colors Jim. The stars are as round as I've seen in some time. Looks like you have your observatory setup dialed in well.

Steve

[Ylem]

That's awesome Jim, and congratulations

[Michael131313]

Thanks Jim for the great image and the excellent information too.

[starfield]

Thanks, Jim. Great shot and congratulations on the APOD.

A quick question on your gain settings. I noticed you bumped the gain on your Lum channel to 140. How do you know when to push the gain and then how do you determine how much? I'm still new to the world of LRGB and curious how folks arrive at different gain settings.

[XCalRocketMan]

Awesome shot - a 2-fer! Very nice, and congrats on the TSS APOD.

[jthommes]

Thanks for the kind comments and the congrats folks. They are much appreciated. Sorry it took so long to get back and acknowledge the comments - its been a busy few days.

Fantastic image Jim. Can I ask how you are annotating - in Pixinsight? If so, what catalogue do you use to show up the Quasars as you have done - with light travel time. I've tried using a using a txt file downloaded from the Pixinsight forum as a custom catalog and while it works and indeed shows up the quasars (as below) it gives only minimal information. Also, how do you get the distances on those PGC galaxies.

Thanks for your help.

David.

Thanks David, I use PixInsight to annotate grid, bright stars, and some PGC galaxies. I merge all these in Affinity Photo (A sort of Photoshop look alike). More detailed info comes from Simbad and NED; and other graphics and text I do in Affinity Photo.

A colleague of mine from another forum is working on some software that takes a Vizier download and creates PI annotations with more info. For example, He is focusing on a Quasar Database for PI that allows one to include RMag and z for quasars and also includes the cosmological calculation for Light Travel Time in the PI annotation. I am helping him test it, When its ready, I will encourage him to share it.

As for some of the other object info on galaxies, I get it from NED and manually annotate the image in Affinity Photo (text, ellipses, leader lines, etc.)

Very nice internal details and colors Jim. The stars are as round as I've seen in some time. Looks like you have your observatory setup dialed in well.

Steve

Thanks Steve. I have been doing a lot of work with my Edge 9.25 at f/7 (1644 mm FL) and the CMOS cameras this galaxy season. That's what I have been "dialing in". With my ASI294, I am at 0.55 arcsec/pix native image scale. If I use the unlock mode on the ASI294, I am at 0.275 - but with 4x file sizes.

Thanks, Jim. Great shot and congratulations on the APOD.

A quick question on your gain settings. I noticed you bumped the gain on your Lum channel to 140. How do you know when to push the gain and then how do you determine how much? I'm still new to the world of LRGB and curious how folks arrive at different gain settings.

Thanks Steve, Truth be told, I think I confused the settings here between the ASI 294 (at gain = 121) and the ASI 1600 (gain = 139 or 140). The little extra gain didn't hurt / maybe was helpful. I wasn't going to throw away 4 hours of subs just because I missed the gain setting by 19 points . Having said that though, I have been exploring an exposure spreadsheet for CMOS cameras that is geared toward ZWO. It interesting and it tries to optimize noise and dynamic range of your integrated stack and recommends sub frame exposure and quantity if you input sky brightness and sky noise as well as optical train size / speed and filter used.

[jon.s]

Beautiful capture and congrats on the APOD!