84 replies to this topic

[Starman1]

I went out to a dark site (Bortle 3) with some friends who were interested in stargazing about a month ago for galaxy season with an 8" RC. I severely underestimated the difficulty for inexperienced observers in making out details in certain galaxies despite the extremely favorable conditions (I've been doing visual observation for about 15 years on and off). They could pretty much universally see M104's dust band and the face at the west end of Markarian's Chain (M84/86) with some time, but they described M51 as a featureless disc with two bright patches, and could not see the full length of the Needle (NGC 4565/Caldwell 38), describing it as circular. Meanwhile, I found the M106 field to be rich in nearby galaxies at 40x (and M106 itself to be surprisingly detailed, it's one of my new favorites!) and I could even make out the tails of NGC 3718.

 

Even globulars were a challenge for them, but most of them could at least see the mottled appearance of M13 at 125x, if not resolve it into individual stars. The good part is that most of my friends wanted to spend more time looking at the galaxies to see more detail, so as a side project I might try to compare their descriptions of different objects as we go out more often and they develop more observing experience.

You can ask them questions as they view.  I've found this to be pretty effective at getting them to Observe the object, not just glance at it:

 

Apparent Sz (visual impression): V.Large / Large / Medium / Small / V.Small/ Stellar / Other
Apparent Overall Brightness: Bright / EZ / Moderate / Faint / Very Faint / At Limit
Apparent Shape: Round / Round-Oval / Oval / Elong. / Very Elong. / Lenticular / Other

Nature/shape of core and nucleus?_
Superimposed stars?_
Edge definition Sharp? / Diffuse?  Varies from one side to the other?_
Brightness Gradient: Center barely brighter/a little brighter/much brighter?
Core % of visible galaxy?_

Features of note you can see?_
Comments on Field--any other galaxies? lots of stars or just a few?
Ease of visibility to you?__

By the time they answer the questions, you will have gotten a pretty detailed description, and it will be a LOT more than they saw when they first looked in.

The above is for galaxies.  other types of objects may have different questions.

Edited by Starman1, 11 May 2025 - 04:06 PM.

[ccate]

Starman1, thank you for the questions. Can you produce a few for open and globular clusters?

[Starman1]

Open and globular clusters:

 

Apparent Sz (visual impression): V.Large / Large / Medium / Small / V.Small  
Apparent Overall Brightness: Bright / EZ / Moderate / Faint / Very Faint 
Apparent Shape: Round / Round-Oval / Oval / Irregular / Other Familiar shape?

Apparent Density of stars.  Is there a condensed core?
Richness (# of stars): Rich / moderate / sparse
Detachment in field: Well detached / moderately detached / poorly detached from surrounding field
Range of Mags of stars:  Wide / moderate / narrow
Apparent brightness of members: Very bright / bright/ medium / Faint/ Very faint?
Nature/Shape of core if any?
Core % of visible Cluster?
Concentration in center?
Resolution of stars in cluster (i.e. are all stars seen or is there a haze of unresolved stars?)

Features of note, like any colored stars?
Comments on Field, like filled with stars, barren of stars, other clusters in field?
Ease of visibility at the magnification chosen?

[Brain&Force]

You can ask them questions as they view.  I've found this to be pretty effective at getting them to Observe the object, not just glance at it:

 

Apparent Sz (visual impression): V.Large / Large / Medium / Small / V.Small/ Stellar / Other
Apparent Overall Brightness: Bright / EZ / Moderate / Faint / Very Faint / At Limit
Apparent Shape: Round / Round-Oval / Oval / Elong. / Very Elong. / Lenticular / Other

Nature/shape of core and nucleus?_
Superimposed stars?_
Edge definition Sharp? / Diffuse?  Varies from one side to the other?_
Brightness Gradient: Center barely brighter/a little brighter/much brighter?
Core % of visible galaxy?_

Features of note you can see?_
Comments on Field--any other galaxies? lots of stars or just a few?
Ease of visibility to you?__

By the time they answer the questions, you will have gotten a pretty detailed description, and it will be a LOT more than they saw when they first looked in.

The above is for galaxies.  other types of objects may have different questions.

Thanks for coming up with this list - I might turn this into a printed sheet or even a Google form the next time we go out. (Well, if I can make a Google form in dark mode - it's one of the few things Google hasn't extended dark mode to natively)

[gnowellsct]

They're all easy to observe.

1. "I don't see anything." That's the easiest. It's a bad night or maybe your telescope is too small. Or maybe you have it pointed in the wrong place.

2. "I see a smudge with no particular shape or form." Now we're talking. This is the essence of galaxy observing.

3. If you see spiral structure and something like a clump to one side (star formation area) then you are looking at one of the great Messiers or one of a handful of other galaxies like NGC 6946. Or maybe 6939. I always get them confused because it's a package deal which includes a spiral galaxy and an open cluster.


Greg N

[Asbytec]

They're all easy to observe.

1. "I don't see anything." That's the easiest. It's a bad night or maybe your telescope is too small. Or maybe you have it pointed in the wrong place.

2. "I see a smudge with no particular shape or form." Now we're talking. This is the essence of galaxy observing.
 

Not seeing anything is easy, I suppose, if you know you're in the correct star field. NGC 891 is a good example in a 6" under my skies. It took a few minutes before I caught my first glimpse of the galaxy. Then another and likely some spurious sitings, as well. And so on. Put those genuine sightings together and you have an idea of what the galaxy looks like to you. Not necessarily an image. If all goes well, the non spurious sightings should resemble an image. We learn to discriminate between spurious sightings that don't make sense and actual sightings that make more sense.

 

Seeing a smudge is a starting point. Most of the time when I see a smudge, I wonder how I am going to make anything of it at all. After a reasonable period of time, I usually have a page of notes of several fleeting and not so fleeting sightings. It's often easy to see a stellar nucleus and a brighter core, and any mottling can be apparent. It normally takes a little work to determine the presence of a dust lane at the edge of the galaxy or a rare instance of a spiral arm in a modest aperture. Observe at the limit of your perception until you are sure there is nothing more to see. 

Edited by Asbytec, 13 May 2025 - 06:11 PM.

[itsjack]

Thanks for the host of good advice!

I'm considering trying to go for M51 at some point. How easily will I be able to detect it, and what detail will I see?

[JoeBlow]

Thanks for the host of good advice!

I'm considering trying to go for M51 at some point. How easily will I be able to detect it, and what detail will I see?

 

M51 should be very easy and bright in a 6" from the Northern Hemisphere. I've seen it before in an 8" from Australia, just a few degrees above the horizon. Both it and its companion galaxy were surprisingly bright and M51 had a mottled appearance. This was from a Bortle 3 site, but extremely close to the horizon and close to the light pollution dome of Sydney.

[itsjack]

Thanks Joe, Ursa Major is close to my zenith at the moment, so I assume it shouldn't be too hard to see.

I thought it may have been difficult because it was a face on spiral galaxy, and they tend to have low surface brightnesses. However, based on your advice and some other lists I've found, I don't think it will be very difficult.

[JoeBlow]

Thanks Joe, Ursa Major is close to my zenith at the moment, so I assume it shouldn't be too hard to see.

I thought it may have been difficult because it was a face on spiral galaxy, and they tend to have low surface brightnesses. However, based on your advice and some other lists I've found, I don't think it will be very difficult.

 

True, it's a face on spiral, but M51 has an unusually high surface brightness for its class. I say definitely go for it!