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Observing >> Deep Sky Observing

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David E
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How deep have you gone?
      #5784667 - 04/07/13 08:04 PM Attachment (63 downloads)

Those of you with monster dobs, I'm wondering how dim a galaxy you've managed to see, in terms of listed magnitude? I noticed a small galaxy on a POSS II image (see below, boxed in red) about 2/3º east of the Ghost Of Jupiter in Hydra. I couldn't identify it at first, it has no NGC or IC number. It turns out to be face-on spiral galaxy PGC030760, shown at magnitude 14 in StarryNight Pro. The brightest stars in the grouping just above it are magnitudes 10.5 to 11.5, (the star immediately to its upper left is magnitude 11.6) so I would think this galaxy would be possible as a visual target in a big enough scope. Has anyone nabbed this one, or willing to give it a try?

Edited by David E (04/07/13 08:05 PM)


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IVM
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Reged: 01/07/08

Loc: Western New York
Re: How deep have you gone? new [Re: David E]
      #5784693 - 04/07/13 08:16 PM

I haven't seen this one, but mag 14 does not require a monster Dob. My 16" goes to mag 16 on galaxies reliably enough from a good enough site (where it is delivered in a small car) and occasionally to mag 17. That said, I suspect that those mag 17 galaxies that I recorded were not measured accurately (although the data were from NED). And generally the listed magnitudes this faint are photographic, so they are perhaps 1 magnitude fainter than in the visual band. Your magnitude 14 is probably calculated visual (NED gives photographic mag 15 for this galaxy).

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Akarsh Simha
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Reged: 03/27/07

Loc: Austin, TX, USA
Re: How deep have you gone? new [Re: IVM]
      #5785103 - 04/08/13 12:10 AM

I think some part of PGC is accessible by not-so-big dobs. This object seems to have high surface brightness, but is tiny. If it really is 14th magnitude, it should be easy to spot. The key reason for not spotting UGC and PGC galaxies is usually insufficient magnification, in my opinion.

From Bortle 2 skies, with my 18", it is fairly common to "stumble" upon galaxies that are not NGC/IC at higher powers.


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David E
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Re: How deep have you gone? new [Re: Akarsh Simha]
      #5785297 - 04/08/13 05:16 AM Attachment (24 downloads)

Re-reading April's S&T, Sue French's column has a couple of dim PGC galaxies in it, but not this one. So I would think this one is a good visual target as well. It certainly has some interesting features.

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Starman1
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Re: How deep have you gone? new [Re: David E]
      #5786380 - 04/08/13 04:47 PM

V magnitude 16.0 so far on galaxy integrated magnitudes, though there are a lot of brighter ones in my list that I have not yet observed. The problem is my list roughly stops at mag. 16.5 for galaxies. I will have to compile a much larger list to reach fainter magnitudes. And then there is the problem of inexact magnitudes as the galaxies get fainter.

V magnitude 16.5 on planetaries, so far.

Stellar magnitude 17.3, roughly in NGC 206.

All of the above with a 12.5" in skies of magnitude 21.5-21.7.

Try the Uppsala Galaxy Catalog (UGC). There are some brighter ones there hardly ever mentioned in observing reports.


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Tony Flanders
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Re: How deep have you gone? new [Re: Starman1]
      #5787404 - 04/09/13 05:34 AM

Quote:

Try the Uppsala Galaxy Catalog (UGC). There are some brighter ones there hardly ever mentioned in observing reports.




Wow, now there would be a project for a truly hard-core deep-sky observer: attempt the entire UGC. Sort of like doing the NGC, but on steroids.


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Keith Rivich
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Reged: 06/17/11

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Re: How deep have you gone? new [Re: Tony Flanders]
      #5795111 - 04/12/13 05:55 PM

Myself (18" and 25") and Larry M. (36") played around with this exact challenge a few years ago. We had a very good night: crisp, clear and steady. Most of the galaxies we looked at were ledas and macs with a few ugc and pgc's thrown in.
Long story short...
I was able to see into the mid 18's on "high" surface brightness galaxies. In the 36" we managed upper 18's. A few low 19's we tried went unseen.
Curious side note. In my 18" I was able to reach mid 17's only after first looking at the galaxies in the bigger scopes. Using only the 18" I was able to see high 16's. I guess it helps to know what one should expect to see!


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David E
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Re: How deep have you gone? new [Re: Keith Rivich]
      #5801516 - 04/15/13 09:04 PM

Quote:

Curious side note. In my 18" I was able to reach mid 17's only after first looking at the galaxies in the bigger scopes. Using only the 18" I was able to see high 16's. I guess it helps to know what one should expect to see!




I agree with that. I've experienced that same effect, finding dim objects in my 4" refractor only after I've seen it with my 8" Dob (albeit a lot dimmer). It happened that way with the little planetary in M46.


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azure1961p
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Re: How deep have you gone? new [Re: David E]
      #5801778 - 04/15/13 11:35 PM

With my 8" under mag 6.2v skys: 13.5v for a galaxy, not blue mag mind you. Farthest distance on a normal galaxy, about 300 million light years. Faintest star -15v.

Pete


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IVM
scholastic sledgehammer


Reged: 01/07/08

Loc: Western New York
Re: How deep have you gone? new [Re: azure1961p]
      #5802432 - 04/16/13 12:03 PM

These, Pete, are the magnitudes I reached with my 7" (a Meade Mak with UHTC coatings). Generally I would not expect to see a difference between 8 and 7 inches, and our comparison confirms this. Actually my numbers that I remember were 13.4 and 14.9 respectively.

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azure1961p
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Re: How deep have you gone? new [Re: IVM]
      #5803447 - 04/16/13 07:55 PM

Ha! Look at that!

You've got great eyes buddy!!

Pete


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GlennLeDrew
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Re: How deep have you gone? new [Re: azure1961p]
      #5806097 - 04/18/13 05:33 AM

At some point, atmospheric seeing will be the limiter to faint (read: small) galaxy detection. And in the main, such a 'contest' will favor those with a monster scope under a dark, steady sky.

But isn't this really just an academic exercise? I've never understood the 'thrill' of detecting a featureless smudgy dot of a distant galaxy, which is just one of thousands like it (in apparent brightness, morphology and size.) Unless it's about bragging rights.


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Starman1
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Re: How deep have you gone? new [Re: GlennLeDrew]
      #5806394 - 04/18/13 10:39 AM

Quote:

At some point, atmospheric seeing will be the limiter to faint (read: small) galaxy detection. And in the main, such a 'contest' will favor those with a monster scope under a dark, steady sky.

But isn't this really just an academic exercise? I've never understood the 'thrill' of detecting a featureless smudgy dot of a distant galaxy, which is just one of thousands like it (in apparent brightness, morphology and size.) Unless it's about bragging rights.



Not to mention the bias shifts toward ellipticals at great distances because they are typically the largest and brightest galaxies. If I'm looking at a galaxy at 500mly, I can almost guarantee it's an elliptical.

But the merit to ferreting these faint little suckers out is to learn the limits of the scope, learn the limits of your own eye, and to uncover associations and perhaps interactions between galaxies. And sometimes it's really cool to realize that there are more galaxies in the field of view than there are visible stars in the field of view (not counting the stars in galaxies themselves).

Picking up the distance spec is usually interesting, too, because it's fascinating to realize that when the light was emitted by that really faint little pfft that multicellular life on Earth was a relatively new thing.

Edited by Starman1 (04/18/13 10:41 AM)


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deepskydarrell
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Reged: 03/09/08

Loc: Abbotsford, BC Canada
Re: How deep have you gone? new [Re: David E]
      #5806534 - 04/18/13 12:27 PM

Quote:

I noticed a small galaxy on a POSS II image (see below, boxed in red) about 2/3º east of the Ghost Of Jupiter in Hydra. I couldn't identify it at first, it has no NGC or IC number. It turns out to be face-on spiral galaxy PGC030760, shown at magnitude 14 in StarryNight Pro. The brightest stars in the grouping just above it are magnitudes 10.5 to 11.5, (the star immediately to its upper left is magnitude 11.6) so I would think this galaxy would be possible as a visual target in a big enough scope. Has anyone nabbed this one, or willing to give it a try?




David, in your original image the five brightest field stars are shown in Uranometria so they're mag 9.75 or less. These stars make it easy to identify the galaxy and Urano lists the galaxy as MCG 3-27-14 at 10h 27'30.1" -18°48'37" with a mag of 13.3, size:0.7 X 0.5' surface brightness: 12.0

just for the record.

DSD.


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deepskydarrell
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Reged: 03/09/08

Loc: Abbotsford, BC Canada
Re: How deep have you gone? new [Re: GlennLeDrew]
      #5806608 - 04/18/13 12:55 PM

Quote:

But isn't this really just an academic exercise? I've never understood the 'thrill' of detecting a featureless smudgy dot of a distant galaxy, which is just one of thousands like it (in apparent brightness, morphology and size.) Unless it's about bragging rights.




Understanding the Thrill of finding featureless fuzzy dots: I guess a fellow with larger aperture trying to explain this to a fine fellow with binos would be a bit like a guy from Ottawa trying to explain to a guy from British Columbia the value of the french language. Either way they just can't understand it. Maybe if I really learned french I'd understand that value? Perhaps actually experiencing it, or immersed in it makes the difference? Could the same be true of finding faint fuzzies?

DSD.


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Smithfr2000
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Reged: 09/12/09

Loc: Nantes - France
Re: How deep have you gone? new [Re: deepskydarrell]
      #5806910 - 04/18/13 03:22 PM

Quote:

Understanding the Thrill of finding featureless fuzzy dots: I guess a fellow with larger aperture trying to explain this to a fine fellow with binos would be a bit like a guy from Ottawa trying to explain to a guy from British Columbia the value of the french language. Either way they just can't understand it. Maybe if I really learned french I'd understand that value? Perhaps actually experiencing it, or immersed in it makes the difference? Could the same be true of finding faint fuzzies?

DSD.




Essaie alors d'imaginer un compte rendu d'observation de petites galaxies écrit en français.

Then, try to imagine a faint fuzzies observation report written in french

Edited by Smithfr2000 (04/18/13 03:23 PM)


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deepskydarrell
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Reged: 03/09/08

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Re: How deep have you gone? new [Re: Smithfr2000]
      #5807002 - 04/18/13 03:53 PM

Thanks Smithfr,

I caught half of that. It's amazing how many of our words have a common root. Many western Canadians have dificulty in understanding the need for our official national bilingualism. Some may even think it's crazy, perhaps like collecting faint galaxies. But some of us really enjoy collecting them.

DSD.


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Bill Barlow
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Re: How deep have you gone? new [Re: Starman1]
      #5807704 - 04/18/13 08:55 PM

I agree, Don. It puts into perspective how large and vast the Universe is when you look at a seemingly small/faint patch of light hundreds of millions of light years away. I have seen faint galaxies in my C14 from a yellow zone about 400-450 MLY away. One that comes to mind is Copelands Septet.

I have been seeing how many of the Hickson Compact Galaxy Groups that I can find/see in this C14. I use an altaz mount (UA Unistar Deluxe on a giant Meade tripod) with no go-to..a S+T Pocket Sky Atlas, finder charts and a SV 10x60 finder scope and a handheld pair of 10x50 binoculars to help with the star hops. So far in the last year or so, I have seen about 25 of them. It is a lot of fun and rewarding when I can finally find them and see some of the faint light from these distant cosmic islands.

Bill


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azure1961p
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Re: How deep have you gone? new [Re: deepskydarrell]
      #5809875 - 04/20/13 12:10 AM

Quote:

Quote:

But isn't this really just an academic exercise? I've never understood the 'thrill' of detecting a featureless smudgy dot of a distant galaxy, which is just one of thousands like it (in apparent brightness, morphology and size.) Unless it's about bragging rights.




Understanding the Thrill of finding featureless fuzzy dots: I guess a fellow with larger aperture trying to explain this to a fine fellow with binos would be a bit like.




That doesn't pose a point really. You could compare a 50" reflector to a 50mm finder scope and some things don't matter. The perception of threshold fuzzy dot like galaxies is enjoyed with binos (if not more) than huge aperture. The magnitudes are fainter obviously but not the relative detection threshold of the eye brain. Every aperture has tiny fuzzy galaxies at the threshold. More with huge aperture but not enough to make the experience particularly exclusive in this sense.

Pete


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Bill Weir
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Re: How deep have you gone? new [Re: azure1961p]
      #5811042 - 04/20/13 02:30 PM

Is this about deepest furthest object or about how far has one pushed their eyes? For me I guess my response should be posted in the Planetary forum as there are two. The first is Mercury naked eye with the Sun still above the horizon and the second is seeing Venus as a crescent naked eye. Both were extremely difficult observations and on both occasions involved about a week of preparation and attempts. As has been suggested each persons' deep could and should depend on the aperture available, sky conditions, location etc, etc.... On my occasions they involved about 2-3mm of aperture.

They were both very fun chases.

Bill


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