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#1 Starman1

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Posted 19 February 2013 - 03:12 PM

Every now and then, but not all the time, I like to see just how deep my 12.5" can see. Over the years, I've run into many challenges, but the following are some I've pursued this year. Only #13 has eluded me this last year. I've seen to H1, but not H2 or I. Yet.

If you have some of your own, post them here and we'll see just where this thread goes.

Some challenges for the 12.5", with some a LOT easier than others:

1) The horizontal branch of M14--seeing hundreds of stars across the cluster. HB=mag.17.1
2) Seeing individual stars in NGC206 in M31. There are 6 superimposed stars in the Milky Way. If you see a dozen or more, you're picking up stars in M31. Mags 17.03-17.55
3) Seeing the spiral arms in M81
4) Seeing the spiral arms in NGC2403
5) Seeing the spiral arms in NGC7331
6) Seeing white swirls inside the Great Red Spot on Jupiter
7) Seeing albedo markings on Ganymede
8) Seeing shadows of the festoons on the edge of an EQ Band on Jupiter
9) Seeing 6 distinct galaxies in Hickson 92, aka "Stephan's Qunitet"
10) Seeing IC4617 on the outskirts of M13
11) Seeing IC1296 on the outskirts of M57
12) Seeing the central star in M57
13) Seeing the G-H1-H2, and I stars in the Trapezium
14) Seeing the jet in M87
15) Seeing the "fingers" protruding from NGC5195 (companion of M51)

My hope is to add to this list to provide some year-round challenges for 10-12"+ apertures.

#2 deepskydarrell

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Posted 20 February 2013 - 01:12 AM

Thanks Don, for the start of a fantastic Challenge List. I've only had my refigured mirror since September and the weather up here has been dismal as usual, but these are the types of things I'd like to test on. After 10 years of pushing the envelope with my old optics I'm pretty much overwhelmed by all the sights that I want to revisit with my new eyes.

Would the Draco Dwarf meet the criteria?

Darrell.

#3 hbanich

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Posted 20 February 2013 - 02:41 AM

A few challenge objects off the top of my head and in no particular order. All with my 28 inch f/4 Newtonian unless otherwise noted:

1. Einstein's Cross. So far I've seen three of the lensed images and the lensing galaxy.
2. Hickson 50. My best so far is three Hickson 50 galaxies.
3. Stars with NGC 604.
4. The second central star within M57.
5. Knots within M87's jet.
6. IC 4277 near M51. This is a bugger!
7. The southern arc in Cassiopeia A. No luck yet, but the northern arc is really cool.
8. Abell 85. No luck yet.
9. HH 399 in the Trifid Nebula. No luck yet.
10. A small but photographically bright HII region at the end of M51's bridge. No luck yet.

#4 Starman1

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Posted 20 February 2013 - 10:10 AM

Would the Draco Dwarf meet the criteria?

Darrell.

At almost the same size as M33 and 5 magnitudes fainter overall, the SB of this galaxy is going to be quite low.
It would be interesting to see what scopes can see it.

#5 JakeSaloranta

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Posted 20 February 2013 - 11:20 AM

Would the Draco Dwarf meet the criteria?


I think UGC 10822 is going to be faint no matter the aperture. It can be seen with giant binoculars, small refractors and anything above that.

/Jake

#6 Astrojensen

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Posted 20 February 2013 - 11:43 AM

I think UGC 10822 is going to be faint no matter the aperture. It can be seen with giant binoculars, small refractors and anything above that.


IF there's no light pollution, no Moon and the atmosphere has been purged of any haze by a hurricane or something like that, AND you're at 10,000 feet altitude... ;)

But yes, I've heard of visual sightings. I've yet to see anything but stars in the region. The UMi dwarf is no better. They do have the advantage of passing right overhead here.


Clear skies!
Thomas, Denmark

#7 LivingNDixie

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Posted 20 February 2013 - 12:28 PM

Thomas,
Not to nitpick but hurricanes actually don't purge the atmosphere of moisture after they pass. Been through a couple of hurricanes :(

But you are right dry skies with low humidity is good though :)

#8 nytecam

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Posted 20 February 2013 - 12:55 PM

A few challenge objects off the top of my head and in no particular order. All with my 28 inch f/4 Newtonian unless otherwise noted:

1. Einstein's Cross. So far I've seen three of the lensed images and the lensing galaxy.
2. Hickson 50. My best so far is three Hickson 50 galaxies.
3. Stars with NGC 604.
4. The second central star within M57.
5. Knots within M87's jet.
6. IC 4277 near M51. This is a bugger!
7. The southern arc in Cassiopeia A. No luck yet, but the northern arc is really cool.
8. Abell 85. No luck yet.
9. HH 399 in the Trifid Nebula. No luck yet.
10. A small but photographically bright HII region at the end of M51's bridge. No luck yet.

Wow Howard - what an impossible list but obvious worthy for 28" Dob :o

Just dug out my M51 brief shot from last April with edge-on gxy IC4277 @ m17.95 [circled] and unidentified brighter m17.3 gxy [square box], according to Sloan DSS, in immediate field. Good luck in your quest :bow:

Attached Files



#9 leviathan

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Posted 20 February 2013 - 01:07 PM

6, 7, 8, 12, 13 should be easy for 12". But 17-17.5m for that scope I think is impossible.

#10 JakeSaloranta

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Posted 20 February 2013 - 01:15 PM

IF there's no light pollution, no Moon and the atmosphere has been purged of any haze by a hurricane or something like that, AND you're at 10,000 feet altitude... ;)


I was hoping the light pollution part would come without saying but the others are so-so. I've seen both the Draco and Ursa Minor Dwarfs with a 4.3" Tal-1 refractor from Nokia, Finland less than 20 kilometers from the 3rd largest city in Finland - Tampere. No altitude and "plenty" of light pollution in the worst parts of the sky but still dark, SQM-L 21.30+ and NELM 7.0+ skies.

I also personally know that both of the dwarfs have been seen with even smaller apertures. These include observations at least by Jyri Lehtinen (with a 10 cm scope from NOT, La Palma, NELM ~8.0) and Steve Waldee from CA with a 8 cm scope. I also remember some guy from France(?) that saw them with a pair of giant binoculars. There's surely a thread of it here on CN / Google.

The fact that the objects rise ~70 deg above the horizon surely helps up here in the north.

/Jake

#11 Astrojensen

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Posted 20 February 2013 - 02:02 PM

The amount of moisture in the atmosphere above is sure going to be a huge factor in the visibility of these very difficult galaxies. I've got dark skies (SQM 21.7 is just ten minutes in car from my house), but my skies are often gray with haze.


Clear skies!
Thomas, Denmark

#12 JakeSaloranta

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Posted 20 February 2013 - 02:36 PM

The amount of moisture in the atmosphere above is sure going to be a huge factor in the visibility of these very difficult galaxies. I've got dark skies (SQM 21.7 is just ten minutes in car from my house), but my skies are often gray with haze.


Jeez, so fine you have to have "dark skies and relatively low humidity" to see it. Keep in mind that low humidity never occurs in here. My observation and sketch were made in April and the weather notes do not mention snow cover so with the breeze... humidity probably was as close to "low" (40-50%) as it ever can get in here.

The point was, that Draco Dwarf can be seen from less than pristine locations as well and even with smaller apertures.

/Jake

#13 Astrojensen

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Posted 20 February 2013 - 03:47 PM

My observation and sketch were made in April and the weather notes do not mention snow cover so with the breeze... humidity probably was as close to "low" (40-50%) as it ever can get in here.

The point was, that Draco Dwarf can be seen from less than pristine locations as well and even with smaller apertures.



I think haze might not always be associated with humid conditions near the ground (but probably most often is). I think your location might possibly have a lot lower moisture content in the upper atmosphere than here. I have, as mentioned, quite dark skies, but I've never seen the UMi or Draco dwarfs, even when looking for them with quite suitable gear, but perhaps I've not tried hard enough.

Do you have an idea of how much more difficult they are, compared to Coddington's Nebula, IC 2574? I've seen that one as a ghostly glow with one or two clumps in a 6" f/8 achromat at 40x, with a 30mm ES82 eyepiece. The clumps were easier with an 18mm ES82, 67x.

I've only had the ES eyepieces for a month and a half, but the 30mm on the 6" refractor is going to be my scope of choice on the next assault on the Draco and UMi dwarfs.

That you consider the Draco dwarf possible under less than ideal skies is a great encouragement for me! :)


Clear skies!
Thomas, Denmark

#14 J Lowrey

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Posted 20 February 2013 - 03:52 PM

Howard,

Could you be more specific on where the knot in M51 is that you are talking about in your post.

Thanks

#15 David Knisely

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Posted 20 February 2013 - 04:00 PM


Would the Draco Dwarf meet the criteria?

Darrell.

At almost the same size as M33 and 5 magnitudes fainter overall, the SB of this galaxy is going to be quite low.
It would be interesting to see what scopes can see it.


If you mean 10th magnitude UGC 10822, that has been seen in some rather modest apertures (six inches for example). I even caught it one night at the Nebraska Star Party in my 9.25 inch SCT, which surprised me a bit. Clear skies to you.

#16 David Knisely

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Posted 20 February 2013 - 04:27 PM

Well, let's see...

1) The horizontal branch of M14--seeing hundreds of stars across the cluster. HB=mag.17.1

Humm... I see many stars in M14 in my 10 inch, but they are probably AGB stars mostly.

2) Seeing individual stars in NGC206 in M31. There are 6 superimposed stars in the Milky Way. If you see a dozen or more, you're picking up stars in M31. Mags 17.03-17.55

It looks granular in my 14 inch and there are a few stars there, but which are M31 stars and which are not I don't know about.

3) Seeing the spiral arms in M81

Been there. Done that (in an 8 inch f/7 no less).

4) Seeing the spiral arms in NGC2403

Lots of patchy detail in it in my 10 inch, but full arm structure is elusive.

5) Seeing the spiral arms in NGC7331

Done that (in a 10 inch this time).

6) Seeing white swirls inside the Great Red Spot on Jupiter

I don't know about "white swirls", but under good seeing, the interior of the red spot starts to show some arc-like inner detail in my 10 inch. In my 14 inch, the interior structure is unmistakable, although it isn't quite "white".

7) Seeing albedo markings on Ganymede

I have seen the "dot" in my 9.25 inch SCT, but much more required my 14 inch Newtonian.

8) Seeing shadows of the festoons on the edge of an EQ Band on Jupiter

You're kidding, right? :)

9) Seeing 6 distinct galaxies in Hickson 92, aka "Stephan's Qunitet"

Well, four with the 9.25 inch and five with my 14 inch (don't know which is the 6th galaxy unless you want to count the more distant NGC 7320C over four arc minutes to the northeast of NGC 7320).

10) Seeing IC4617 on the outskirts of M13

That one took a 12.5 inch Portaball at the Nebraska Star Party to do, as I failed using my 10 inch. In my 14 inch Newtonian, it was no problem last summer.

11) Seeing IC1296 on the outskirts of M57

I have done that with my 10 inch Newtonian, although I don't know about it being on the "outskirts" of the nebula.

12) Seeing the central star in M57

Did that one night from my driveway in my 9.25 inch SCT.

13) Seeing the G-H1-H2, and I stars in the Trapezium

Nope, not yet, but quite frankly, I haven't had a lot of interest in seeing them.

14) Seeing the jet in M87

Tried with my 14 inch but failed due to seeing. I will keep trying.

15) Seeing the "fingers" protruding from NGC5195 (companion of M51)

The "prongs" as I like to call them were not all that hard in my 10 inch one exceptionally dark night, but it does take a really good night to do it. I have had some halfway decent nights where they failed to show up well even in my 14 inch, other than as faint hints of something trailing off to the north of NGC 5195.

Keep those challenges coming! Clear skies to you.

#17 Astrojensen

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Posted 20 February 2013 - 04:40 PM

That's quite an impressive list of achievements!


Clear skies!
Thomas, Denmark

#18 tnakazon

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Posted 20 February 2013 - 05:50 PM

With my 3.9" Orion SkyScanner F/4 Newtonian, three difficult objects I've been able to pick-up with it were:


1) NGC 6822 or Barnard's Galaxy in Sagittarius (visual mag.=9.9, surface brightness=15.5)

2) NGC 4236 in Draco (visual mag.=9.9, surface brightness=15.2)

3) NGC 4145 in Canes Venatici (visual mag.=11.2, surface brightness=14.6)


All of these were observed under dark skies (green/blue zone).

Barnard's is probably visible with scopes of even smaller aperture, just as long as you have dark skies.

#19 Starman1

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Posted 20 February 2013 - 06:00 PM

6, 7, 8, 12, 13 should be easy for 12". But 17-17.5m for that scope I think is impossible.

Well, not really. It depends on whether we are talking stars or DSOs.
With my 12.5", I've seen stars of magnitude 17.35, at the zenith, at high power, and under near-optimum conditions (mag.21.7 skies with near-perfect seeing).
Mag. 16.8 is visible nearly every time I observe--sometimes more than 80% of the time. Try downloading the magnitude chart around M57 for some really faint magnitudes:
http://www.astrochri.../page.php?pg=20

As for DSOs, I have a few observations logged that reach past magnitude 16, notably:
NGC4297
NGC6027C (In Seyfert's Sextet)
PK110-12.1 planetary
NGC3005

One of my favorite challenges, though not quite as dim, is the galaxy at the edge of Abell 70. Both galaxy and planetary visible without filter. An O-III makes the planetary stand out, but reduces the galaxy to merely a bright spot on the periphery of the nebula.

#20 Astrojensen

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Posted 20 February 2013 - 06:20 PM

With my 3.9" Orion SkyScanner F/4 Newtonian, three difficult objects I've been able to pick-up with it were:


1) NGC 6822 or Barnard's Galaxy in Sagittarius (visual mag.=9.9, surface brightness=15.5)

2) NGC 4236 in Draco (visual mag.=9.9, surface brightness=15.2)

3) NGC 4145 in Canes Venatici (visual mag.=11.2, surface brightness=14.6)


I've not seen NGC 6822 or 4145, but I've seen NGC 4236 a couple of times or three, with my 63mm Zeiss. Usually it's extremely hard and only visible as a very faint, slightly elongated glow (the bulge), but one time I saw it as a huge, very elongated object, one of the biggest near edge-on galaxies I've seen. Truly a fascinating object. That night I saw many, many objects like I've never seen them before or since. The sky was coming alive with galaxies and stuff.


Clear skies!
Thomas, Denmark

#21 Astrojensen

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Posted 20 February 2013 - 06:26 PM

Actually, given its huge size, NGC 4236 should be visible in 10x50 binoculars. I've yet to do this, though. Conditions must be superb.

I am slowly making a list of galaxies visible (or in some cases, theoretically visible, because I've yet to see them or even hear about observations) in a 10x50 or smaller binocular. It's getting pretty long already. There are some insane challenges on that list! I will of course not include everything. There must be a fair chance to see the object. If it is small, it must be pretty bright or if it is very faint, then it must be large.


Clear skies!
Thomas, Denmark

#22 Starman1

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Posted 20 February 2013 - 06:38 PM

[quote name="David Knisely"]Well, let's see...

1) The horizontal branch of M14--seeing hundreds of stars across the cluster. HB=mag.17.1

Humm... I see many stars in M14 in my 10 inch, but they are probably AGB stars mostly.
[/quote]
Agreed. But when you see literally hundreds of faint stars covering the globular from edge to edge, you know you've reached the HB of the globular.
[quote]
2) Seeing individual stars in NGC206 in M31. There are 6 superimposed stars in the Milky Way. If you see a dozen or more, you're picking up stars in M31. Mags 17.03-17.55

It looks granular in my 14 inch and there are a few stars there, but which are M31 stars and which are not I don't know about.
[/quote]
Use powers over 250X, and if you count more than 6 stars, you are seeing stars in M31. The supergiant O and A stars there are, on average, 2 full magnitudes brighter than most stars in M31, and put off prodigious energies. I and a friend have counted up to 15 stars.
[quote]
3) Seeing the spiral arms in M81

Been there. Done that (in an 8 inch f/7 no less).
[/quote]
Lucky fellow to see such dark skies. It takes me waiting for the galaxy to culminate and a really dark night. The "glow" of the spiral arms is usually there, but seeing the actual arms, I've found, is tough.
[quote]
4) Seeing the spiral arms in NGC2403

Lots of patchy detail in it in my 10 inch, but full arm structure is elusive.
[/quote]
Especially because they are tight in to the core because of our perspective. The oval glow of the arms is always there, but seeing the gaps between the arms and the core is tough.
[quote]
5) Seeing the spiral arms in NGC7331

Done that (in a 10 inch this time).
[/quote]
Yeah, this one is easier. First because of the passage near the zenith, and also because it's far enough away the spiral arms aren't spread out to invisibility. When you can see the 4 companions, the arms are usually there.
[quote]
6) Seeing white swirls inside the Great Red Spot on Jupiter

I don't know about "white swirls", but under good seeing, the interior of the red spot starts to show some arc-like inner detail in my 10 inch. In my 14 inch, the interior structure is unmistakable, although it isn't quite "white".
[/quote]
Agreed. I'm not exactly certain what atmospheric conditions have to pertain in order to see the salmon color of the GRS and see the swirls within as white. Normally, they are just slightly differing shades of gray. But when the color of the GRS is plain as day, the white swirls within (sometimes merely arcs) are visible at >300X.
[quote]
7) Seeing albedo markings on Ganymede

I have seen the "dot" in my 9.25 inch SCT, but much more required my 14 inch Newtonian.
[/quote]
This one depends so heavily on atmosphere, I am not certain of the minimum aperture necessary. I never saw Ganymede as a disk with variegated brightness until experiencing seeing conditions where the planet had no visible scintillation at all for 29 of 30 seconds, allowing me to go to 456X and see a sharply detailed planetary surface.
[quote]
8) Seeing shadows of the festoons on the edge of an EQ Band on Jupiter

You're kidding, right? :)
[/quote]
Nope. On the same night as mentioned, the gray-green festoons hung out above the ocher-colored EB and were lined with dark edges only on one side. I finally realized that that was because the shadows of the festoons were cast on the clouds below, making the edges of the festoons black on one side. Each festoon looked not just like the typical swirl or arc, but a mottled bunch of cloud, sort of like the center of M42.
It was an uncanny night. I never saw that before and haven't seen it since. Could be I was seeing a darkish chemical in the atmosphere on the downwind side of each festoon instead of a shadow, but the white storms in the depths of the ocher EB did not show that, and some of them were being torn apart and appeared streaked in the downwind direction.
[quote]
9) Seeing 6 distinct galaxies in Hickson 92, aka "Stephan's Qunitet"

Well, four with the 9.25 inch and five with my 14 inch (don't know which is the 6th galaxy unless you want to count the more distant NGC 7320C over four arc minutes to the northeast of NGC 7320).
[/quote]
I am counting 7320C because it is still close, even at 304X. The hardest thing is to split the cores of NGC7318A and B. 7320 is considered to not be a 'true' member of the group (being nearer) while 7320C IS considered a member. Go figure.
[quote]
10) Seeing IC4617 on the outskirts of M13

That one took a 12.5 inch Portaball at the Nebraska Star Party to do, as I failed using my 10 inch. In my 14 inch Newtonian, it was no problem last summer.
[/quote]
It took 12.5" for me to spot this. I looked for it, but never actually found it with my 8" SCT.
[quote]
11) Seeing IC1296 on the outskirts of M57

I have done that with my 10 inch Newtonian, although I don't know about it being on the "outskirts" of the nebula.
[/quote]
Bad choice of words. In same field of view and near the nebula would be a better choice of words. I first spotted it in my 8" SCT. I am not certain what the minimum aperture is.
Here is a GREAT picture:
http://www.starshado...y.cfm?imgID=154

[quote]
12) Seeing the central star in M57

Did that one night from my driveway in my 9.25 inch SCT.
[/quote]
You must have had superb seeing.
[quote]
13) Seeing the G-H1-H2, and I stars in the Trapezium

Nope, not yet, but quite frankly, I haven't had a lot of interest in seeing them.
[/quote]
Well, I've caught the G and H1, but have yet to catch H2 or I. I think it takes superb conditions.
[quote]
14) Seeing the jet in M87

Tried with my 14 inch but failed due to seeing. I will keep trying.
[/quote]
It took me 5 or 6 tries, and I've only seen it once in the 12.5". It was easy in a friend's 28"
[quote]
15) Seeing the "fingers" protruding from NGC5195 (companion of M51)

The "prongs" as I like to call them were not all that hard in my 10 inch one exceptionally dark night, but it does take a really good night to do it. I have had some halfway decent nights where they failed to show up well even in my 14 inch, other than as faint hints of something trailing off to the north of NGC 5195.
[/quote]
Yup. It has to be superbly dark and the galaxy near culmination for me. I'm more interested in seeing the 'arc' around the companion and the dark lane in the bridge.
[quote]
Keep those challenges coming! Clear skies to you. [/quote]
Most of the objects in the "Aintno" list are a little too faint for we mere mortals. I'm hoping we will compile a good list from posts in this thread.

#23 David Knisely

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Posted 20 February 2013 - 07:07 PM

Starman1 posted:

Quote:

8) Seeing shadows of the festoons on the edge of an EQ Band on Jupiter

You're kidding, right?



Nope. On the same night as mentioned, the gray-green festoons hung out above the ocher-colored EB and were lined with dark edges only on one side. I finally realized that that was because the shadows of the festoons were cast on the clouds below, making the edges of the festoons black on one side. Each festoon looked not just like the typical swirl or arc, but a mottled bunch of cloud, sort of like the center of M42.
It was an uncanny night. I never saw that before and haven't seen it since. Could be I was seeing a darkish chemical in the atmosphere on the downwind side of each festoon instead of a shadow, but the white storms in the depths of the ocher EB did not show that, and some of them were being torn apart and appeared streaked in the downwind direction.


I have to take a little issue with the idea of a cloud "shadow". There are small linear bluish/dark grey clouds or features that hug the main belts and festoons, but these are thought to be either "clearings" in the upper cloud deck or actual bluish clouds rather than shadows. With Jupiter, any shadows cast by higher clouds would tend to fall almost directly beneath them when near disk center, so from Earth, they would be difficult to impossible to see since the sun is always behind us when viewing Jupiter. Clear skies to you.

#24 tnakazon

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Posted 20 February 2013 - 07:27 PM

I've not seen NGC 6822 or 4145, but I've seen NGC 4236 a couple of times or three, with my 63mm Zeiss. Usually it's extremely hard and only visible as a very faint, slightly elongated glow (the bulge), but one time I saw it as a huge, very elongated object, one of the biggest near edge-on galaxies I've seen. Truly a fascinating object. That night I saw many, many objects like I've never seen them before or since. The sky was coming alive with galaxies and stuff.

Clear skies!
Thomas, Denmark

I saw NGC 4236 just once, at a Star Party in a green zone site. I remember the first time I tried looking for it - it was lower in the horizon and I thought I glimpsed it (the nucleus at least) but as it moved lower down the horizon, it literally disappeared from sight. Determined that I would see it with certainty the next night, I got my telescope set up a few hours earlier this time. Being higher up in the sky, I saw the breadth of the galaxy and yes, it was huge. I was really proud of that sighting because of the ridiculously low surface brightness of this galaxy.

NGC 6822 is lower down the horizon in the Northern Hemisphere, so I can see how it would be extremely difficult to spot from Denmark. I tried and failed to detect it at my orange zone site quite a few times. Only when I went to a blue zone site up in the mountains was I able to see it clearly. NGC 4145 should be relatively easy from your latitude since it would be directly overhead.

I go to Europe once or twice a year on vacation. Looking forward to visiting Denmark (and Copenhagen) soon.

#25 tnakazon

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Posted 20 February 2013 - 07:40 PM

Actually, given its huge size, NGC 4236 should be visible in 10x50 binoculars. I've yet to do this, though. Conditions must be superb.

I am slowly making a list of galaxies visible (or in some cases, theoretically visible, because I've yet to see them or even hear about observations) in a 10x50 or smaller binocular. It's getting pretty long already. There are some insane challenges on that list! I will of course not include everything. There must be a fair chance to see the object. If it is small, it must be pretty bright or if it is very faint, then it must be large.


Clear skies!
Thomas, Denmark

It's fun to try to push a small scope to the limits of its aperture's capabilities (especially with the help of darker skies). I've been doing this with my 3.9" Orion SkyScanner for over 2 years now, and even though I now own bigger 5" & 6" scopes, my 3.9" (100mm) is still my workhorse scope in seeking out new DSO's. My 4.5" Orion StarBlast and 3.1" Orion Short Tube 80 also gets some work in, as well as my 4" Celestron NexStar 102GT (GOTO achromat).

Yup, I always take size and surface brightness into consideration when looking for suitable galaxies as targets for my small scopes.

I've never star-gazed with binoculars, but I do use field glasses occasionally to help point my scope in the right location where the target DSO's are located.






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