23 replies to this topic

[Keith Rivich]

I have a bit of a dilemma. With the full moon firmly ensconced in the middle of the month we now have two dark moon periods each month. At the beginning and end of each month. Looks like I am going to have to pull a Julius Caesar and jack with the calendar! Nah, folks might get upset. So I will just title this next challenge Feb 2.0! 

 

For those not familiar with my challenges each month I present three DSO's for your consideration. An easy object targeted for beginners, a not so easy object for mid to larger scopes from good skies and a difficult challenge that may have you seeking out a 20" scope. Except for the easy object I have either never looked at the more difficult objects or its been so long I don't remember observing. So they are new for me to. 

 

Here we go.

 

Easy

 

Hyades 

Open Cluster

Taurus

04 26 54

15 52 00

Mag .5

Size 5.5°

# Stars  ~380

 

Amazing this naked eye cluster never received a formal NGC or Messier number. Anchored by ruddy Aldebaran the Hyades is a nice V shaped group of stars easily seen in any sky. Binoculars or a wide field scope reveal dozens of extra stars. Bonus: See if you can see the open cluster NGC 1647 (mag 6, 200 stars) just outside the open part of the V. Would probably be a showplace cluster if not for being in the shadow of the Hyades. 

 

**************************************************************************************************************

 

Not So Easy

 

UGCA 150 (MCG -1-24-1)

Galaxy

Hydra

09 10 49

-08 53 30

Mag 11.5

Size  5.3' x 1'

 

I want to say I have looked at this galaxy but I'll be darned if I can remember when or where. Anyway, I would normally call this a pretty easy observation but this edge on (33° tilt) galaxy has a bright ~9th magnitude star sitting right on its western edge which will complicate the view. Looks fun. Don't think I am going soft on you with this one. The difficult object will make up for this (evil laugh).

 

 

*********************************************************************************************************

 

Difficult 

 

AGC 754

Galaxy Cluster

Hydra

09 08 48

-09 38 00

Megastar shows this as Mag10: 15.2  Not sure precisely what this means, maybe someone can interpret. 

Size 50'

Number of galaxies: An astounding 92!

 

This cluster lies just 1° SW of the above UGCA 150. Should be easy to find. But will it be easy to see? The DSS image is astounding with the number of galaxies (this is actually two clusters in the middle of a merger) with quite a few members in the 14th to 15th mag range. Should be visible in a 10" or larger from dark skies. Many are rather small so they should have pretty high surface brightness. Many of the galaxies don't have magnitudes listed but quite a few look to be around 15 to 16th mag. Probably will need an 18" scope to bag these. 

 

 

 

As always good luck and let us know what you see!

[bphaneuf]

Alright Keith.  Game on.

[oldphotonm]

Now I just need the GD clouds to cooperate and GTF away!

[Keith Rivich]

Now I just need the GD clouds to cooperate and GTF away!

What you talking about? Clouds aren't allowed in New Mexico! 

[sgottlieb]

I'll start things off with a couple of observations of UGCA 150.  The first was made with my former 18" Starmaster from my 'local' site in February 2006. I didn't record an SQM reading, but it's often in the 21.3 range

 

This unusual galaxy is a nice edge-on oriented SW-NE, at least 2.0'x0.4'.  A 9th magnitude star (HD 78953) is strikingly superimposed just SW of center and detracts from viewing.  Still, the galaxy was easily seen as a fairly faint streak extending mostly to the NE of the star!  A 13" pair of mag 14/15 stars is superimposed on the northeast extension.  UGCA 150 is located 19' ESE of mag 5.5 20 Hydrae.

 

The second observation was made 12 years later with my current 24-inch from a darker site in southern reaches of the Diablo Range.  Again my SQM-L readings were around 21.3 early on, but after midnight were above 21.5. And there was interesting structure...

 

UGCA 150 presented a fascinating view at 200x.  The galaxy is situated just following mag 9.0 HD 78953 with the star pinned barely off the west end of the nucleus.  The core is very elongated, appearing like a bar.  The long extensions (edge-on with a dust lane) are oriented SW-NE and extend up to 4'x0.6'. The appearance is asymmetrical, with the northeast end twisting slightly towards the north near the tip.  The southwest end is very diffuse and appears to spread out more to the south, seemingly twisting in reverse from the northeast end and creating a subtle "integral sign" effect.  Two mag 13.5/14.5 stars (perhaps slightly fainter) are attached on the following side of the northeast extension.

 

I'm guessing UGCA 150 will be visible in a 10", depending on the observer, site, etc.

 

Steve

 

[sgottlieb]

I believe "Mag10: 15.2" for AGC 754 refers to the 10th brightest member being mag 15.2.

 

But, AGC 754 has a relatively prominent cD galaxy (PGC 25714), which is much brighter, and a slew of dim galaxies huddled nearby.  The blue magnitude of PGC 25714 is ~14.4, so the V mag should be in the mid-13s. I only took a quick look at PGC 25714 with my 18-inch on the same night I looked at UGCA 150, but didn't look around much to see what other members were visible. 

 

This galaxy is by far the brightest in the distant cluster AGC 754 (z = .055, ~780 Mly.)  At 257x it appeared faint, small, oval, 0.4'x0.3', low fairly even surface brightness with a broad, weak concentration.  With averted vision the halo occasionally increased in diameter.  With a careful look, an extremely faint companion popped into view as a small knot off the SW edge [40" between centers].

 

The companion turned out to be PGC 25712.  HyperLeda reports B = 16.36 and the V = 15.26 and it looks like a number of the member galaxies are similar in brightness.  By the way, MegaStar mislabels the cD galaxy as PGC 25712 and applies PGC 25714 to a companion 1' NW.

 

Steve

Edited by sgottlieb, 08 February 2025 - 01:51 PM.

[oldphotonm]

What you talking about? Clouds aren't allowed in New Mexico! 

They've sure been a PITA lately....

[Keith Rivich]

When I was looking at the RealSky overlay on Megastar I picked up on the two galaxies you mention. 

 

 

 

PGC25712 and PGC 25714 do seem be switched as 25712 is clearly the brighter galaxy. I'll have to bug Larry Mitchell about this. He's the person that outlined and oriented all the galaxies in Megastar. Emil (the creator) wrote a utility program so Larry could scan in the galaxies from a copy of the POSS plates at Rice University and add the correct size and outlines to each galaxy. I believe it took him several years to accomplish this for the entire sky. This is also where the MAC (Mitchell Anonymous Catalog) galaxies came from. They had no previous designations. But I digress.

 

Not labeled is the galaxy just to the SSW of 25712. It has a 2MASX designation with a B magnitude of 15 and R 14.5. PGC25712 has a B magnitude of 14.3 and R 13.3.  

[sgottlieb]

Larry did a fantastic job, didn't mean to sound critical.  This kind of confusion is almost unavoidable in such a densely packed region because the original PGC positions were sometimes imprecise.  The two links for PGC 25712 and 25714 above lead to their HyperLEDA pages and you can clearly see the correct IDs (main galaxy PGC 25714 and southwest companion PGC 25712).

 

You have the MACs turned off in your screenshot, but Larry called the southwest companion MAC 0908-0938B instead.

[Keith Rivich]

Larry did a fantastic job, didn't mean to sound critical.  This kind of confusion is almost unavoidable in such a densely packed region because the original PGC positions were sometimes imprecise.  The two links for PGC 25712 and 25714 above lead to their HyperLEDA pages and you can clearly see the correct IDs (main galaxy PGC 25714 and southwest companion PGC 25712).

 

You have the MACs turned off in your screenshot, but Larry called the southwest companion MAC 0908-0938B instead.

I poke fun at Larry all the time when I find a galaxy error in Megastar! I tell him he has to start over...

[balcon3]

Hi Keith, 

I was wondering if you would consider adding a fourth category to your monthly challenges. My main scope is a 4 inch f7.4 refractor. I am not a beginner, so the beginner objects are known to me. But the intermediate challenges seem to be directed towards people with 10 inches or so of aperture. I would be very interested in trying to find objects that are challenging for a 4-5 inch refractor, or up to a 6 inch reflector. I noticed that you do have a. 6 inch scope which I presume is a reflector. Any interest in adding a fourth challenge?

Thank you !

[Keith Rivich]

Hi Keith, 

I was wondering if you would consider adding a fourth category to your monthly challenges. My main scope is a 4 inch f7.4 refractor. I am not a beginner, so the beginner objects are known to me. But the intermediate challenges seem to be directed towards people with 10 inches or so of aperture. I would be very interested in trying to find objects that are challenging for a 4-5 inch refractor, or up to a 6 inch reflector. I noticed that you do have a. 6 inch scope which I presume is a reflector. Any interest in adding a fourth challenge?

Thank you !

I was thinking of getting rid of the easy as none of the beginners seem to be observing such objects. I get zero feedback. I can make the Easy a bit more challenging which should work of for the smaller scopes. 

[balcon3]

I was thinking of getting rid of the easy as none of the beginners seem to be observing such objects. I get zero feedback. I can make the Easy a bit more challenging which should work of for the smaller scopes. 

I, for one, would be very happy with such an arrangement. I would give feedback.

[Pete W]

I, for one, would be very happy with such an arrangement. I would give feedback.

+1 on the modest-aperture challenge idea

[Herodotus]

AGC 754, intriguing. That'll be fun......

[Keith Rivich]

Ok folks, here is my first attempt at an intermediate challenge DSO for smaller scopes. Let me know if this work for you.

 

NGC 3521

Galaxy 

Leo

11 05 49

-00 02 15

Mag  9.3

Size  11' x 7.1'

 

I have looked at this amazing galaxy from TSP several times with the 25". I did note it was easily visible in my 4" finder, but I did not observe it with the smaller scope. The challenge is to see if you can detect the bubble that surrounds the core of the galaxy, particularly the brighter part of the bubble on the east side of the galaxy.

 

[bphaneuf]

AGC 754, intriguing. That'll be fun......

Oh it's on!   Now if only Monday's forecast holds....
 

Edited by bphaneuf, 11 February 2025 - 08:26 PM.

[Keith Rivich]

Oh it's on!   Now if only Monday's forecast holds....
 

I assume you will be using the 24"?

[bphaneuf]

That's afirm

[bphaneuf]

My widest FOV will be the 21mm Ethos at 0.69 degrees, or roughly PGC 25714 east to 25777, so I'll see what I can pull from that circle more or less centered on 25746

[bphaneuf]

Ooh.  Just looked at max elevation for Abell 754 and it never gets much above the trees at this latitude.  Extinction is going to be an issue, along with the light domes around the horizon.  And those guys are way out there on the order of 750 MLY.  Just managing my expectations here. 

[Keith Rivich]

Ooh.  Just looked at max elevation for Abell 754 and it never gets much above the trees at this latitude.  Extinction is going to be an issue, along with the light domes around the horizon.  And those guys are way out there on the order of 750 MLY.  Just managing my expectations here. 

When I picked this particular challenge object I had TSP in mind. Similar altitude as my club site but much darker skies. You going to TSP?

[bphaneuf]

When I picked this particular challenge object I had TSP in mind. Similar altitude as my club site but much darker skies. You going to TSP?

'fraid not
 

[Keith Rivich]

Weather and life in general finally cooperated and I was able to go out to our dark site for a couple of projects.

 

One was to install my newly rebuilt AZ drive gear box that had been giving me vibration problems. Success! The new drive is working flawlessly. I spent the first few hours tweaking the numbers to get the go-to and tracking working as well as possible. I'm close. Just need to burn a moonlit night and get things a little bit better. 

 

Secondly was to install my new Kendrick dew control. I got everything temporarily installed. Just need to go to my electronics store and get a few connectors. 

 

Thirdly was to take a shot at my Feb 2.0 challenge objects! 

 

The night was mediocre at best. SQML was 20.90 (a few tenths darker then we have been having) but the transparency was off quite a bit. Hardly any stars could be seen below ~20° and brilliant Venus all but obliterated the western skies with her wide casting glow. Humidity was off the charts by midnight. I swear I saw a school of fish swim by! 

 

Anyways, with my 25" f/5 scope:

 

UGCA150

 

Very nice galaxy! 

Was an easy star hop from 2nd mag Alphard. I stopped and took a look at NGC 2889 and NGC 2884 along the way. Both face on spirals. Very nice but lacking any detail in our skies. UGCA 150 sits right between an asterism of 5 stars in the 7th mag range that resemble the 5 pips on a die and 19 and 20 Hya (both 5.5 mag). A very easy finderscope field. The galaxy itself was an interesting slash with a bright 9th mag star invading its western edge. High magnification (650x) revealed several stars embedded that gave the galaxy a mottled appearance. I think I caught glimpses of the dark lane along its eastern edge but I wouldn't swear to it. All of its 5.3' x 1' was pretty much visible. 

 

There was another observer out with a 12" scope. Using my TelRad as a guide he was able to get the field in his scope. We could just barely detect the galaxy. If we hadn't seen it beforehand in the 25" we may have overlooked it in the 12". 

 

AGC 754

 

I didn't give this much of a chance but I did detect a few of the brighter galaxies in the cluster. A short little star hop from UGCA 150 the brightest galaxy in the cluster, PGC 25712, wasn't very difficult. Easily seen with my 13mm finder eyepiece. To its SW is the 15th mag galaxy PGC 25697 was just visible, looking like a fat star. Other galaxies would pop up in my averted vision like so much popcorn popping but when I tried to look at them they would disappear. Interesting experience to say the least. 

 

I'll give both of these another look at TSP.