A selection of objects in Triangulum

[Martin Meredith]

As I was inputting the date on the mount last night I noticed it has been many weeks since my last session, way back in October. November here was the wettest on record. So when the sky cleared just before dusk it was too good an opportunity to miss in spite of the 50% moon. With no clear plan I just headed for Triangulum and looked at what I could find on the charts...

I used 15s subs throughout although the last two objects would have benefitted from longer subs (but I found field rotation to be a bit of an issue for longer subs in this part of the sky with my alt-az mount). No calibration frames. StarlightLive was the capture engine and Jocular used for everything else. Other details are on the images.

I always start with something obvious to check the I haven't made some silly mistake during 2-star alignment and the obvious thing in this constellation is M33. This is a little too large for my sensor but even so a lot of detail in the arms can be captured. 

 

The next 'object' is VV 338, an interacting(?) pair consisting of NGC 672 (the brighter of the two) and IC 1727. I observed this for quite a long time as more details were emerging with each sub. The IC galaxy has an interesting structure with several knots lined up along its central part, and a highly-disturbed outer part, resulting in a 'umbrella handle' hook at the top. On the DSS image there are many blue (presumably recent star-forming) regions. This would respond well to colour.

 

Sticking with the VV catalogue of interacting galaxies, here is a field with two such groups, VV 1034 being the group to the upper right with the face-on spiral, and VV 1035 the very close pair below-left of centre.

For VV 1034, the face on is NGC 974, type SABb, and to its right is type S0 NGC 969. It is well worth looking at the DSS image for these galaxies as the spiral in particular has a beautiful appearance which I have failed to capture, including some extremely graceful and thin arms.

For some reason my charts actually identify the very close pair sitting above these two galaxies as VV 1034 (one of these is NGC 970 while the other has a lesser denomination). 

VV 1035 is identified as NGC 978 but is clearly a pair of galaxies (listed as E/S0 and S0).

There are a few mag 18+ galaxies visible in-between the two VVs

 

 

 

Next, a quick look at a galaxy close to the VV groups that appeared to be interestingly flat on the charts and turned out to be so. This is NGC 973. (actual exposure is 9 x 15s = 2m15). This is reminiscent of NGC 891 with its central dust lane cutting the appearance into two. The galaxy below is IC 1815 and has a similar distance of around 240 MLYs, so I wonder if these are also interacting.

 

 

I can never resist looking at Arps. This is one of two Arps in Triangulum and I have to say it is one of the faintest I've observed, requiring a lot of stacking to pull out its peculiarity. This is actually a close pair of galaxies at 599 MLYs distance where the slightly brighter lower galaxy (mag 16.1) shows little distortion, but on close inspection the upper galaxy (mag 16.4) has its long arms drawn out by the interaction. Unlike the other images here (where N is up), I've rotated this to show the appearance as a back-to-front question mark. Again, this is very clear on the DSS image, and in fact the arms are blue along their entire length, something worth returning to on  a moon-free night with colour I think. 

 

 

 

I ended the chilly and relatively brief session seeking out a very distant object for a non-astronomical friend with whom I'd been chatting about distance scales in the universe. This is an unspectacular but nevertheless compelling object: a z > 4.5 quasar, corresponding to a distance of between 10 and 12.5 billion light years depending on the adopted model. It is listed as V mag 18.8 (which looks about right) but I had a hard time at first with this one (and I'd barely count it as an identification but it does just about rise above the noise floor) hence the longish stack. I guess some calibration would have helped...The more precise coordinates are 1h 34 21.6, +33° 7 55.9.

 

 

Thanks for looking!

Martin

[RobertI]

Nice session Martin, interesting selection of objects , I particularly like NGC973. Jocular seems to be working well. In recently gave a talk about EAA to my local astro club, and Jocular made it into the part about EAA software, including one of your YouTube videos! I thought it was a good example of how simple EAA can be with the right tools. 👍

[elpajare]

As always a good selection very well resolved. Congratulations

[AKB]

1 hour ago, RobertI said:

In recently gave a talk about EAA to my local astro club, and Jocular made it into the part about EAA software,

Ooh, I’m about to do the same.  Any possibility of sharing some of the presentation material?

Thanks

Tony

[RobertI]

39 minutes ago, AKB said:

Ooh, I’m about to do the same.  Any possibility of sharing some of the presentation material?

Thanks

Tony

Of course! I’ll pm you later. 🙂

[Martin Meredith]

Thanks everyone. Nice to see Jocular being promoted -- thank you!

Martin

[Mike JW]

Hi Martin,  Good selection of DSOs. I have visited these visually (not the quasar) but not with the camera (other than Arp 98). NGC 973 reminds me of near by NGC 891.

Below is my Arp 98 (C11/ultrastar at f5).

I shall put the quasar on my list - like a challenge.

Mike

[Martin Meredith]

Hi Mike

That's a great capture of Arp 98. I feel I should revisit this on a moonless night.

VV 1034  is another where it ought to be possible to tease out more detail. Here's the DSS image which shows the graceful arms.

Martin

[Mike JW]

Thanks Martin. There is just not enough clear skies to chase down all the many DSOs. I have noted your thought of teasing out more detail for VV1034. The crazy weather of late has seen me out there in 95% humidity skies, below freezing and thoroughly enjoying myself but of course paying the price of wrecked sleep patterns.

I desperately need some very clear nights to capture more of the low down Arps (a few are impossible for me), re-visit a few and pick off the remaining scattered Arps. Tally so far is around the 315 mark. Then I wish to complete the HIcksons and if I am in the region I pick up very distant NGC/IC galaxies.

Thanks as always for your postings, enthusiasm, interesting targets and encouragement.

Have fun

Mike

[Mike JW]

Hi Martin,

I managed to grab an hour clear skies last night before the moon rose and the inevitable cloud rolled in. I took the chance to look at two or your targets, NGC 970 and 978. I have not cleaned up the images. 

NGC 970 - is it a true interacting  pair or a line of site? It does look as if they are interacting (NED has very little info about it)

 

NGC 978

Edited December 15, 2019 by Mike JW