Morning Messiers, TV76, 8/28/2004

Date: Saturday early morning, 28-Aug-2004
Location: Backyard, Palm Springs, California
Equipment: Tele Vue 76 (3" f/6.3) refractor

I always like to visit (or rather revisit) the Messier catalog with a
new telescope. I've had the Tele Vue 76 since February and only have a
few M objects i've not yet seen from home. Having a very small window
of darkness early this morning between moonset and twilight i got up
about 3:45am and went out in the backyard with the TV76. Skies don't
seem as dark as they had been earlier in the week and there is still
some glow over the mountains to the WSW from the recently set moon.

Started with the open clusters in Auriga... M38 with NGC 1907 just to
its south, M36 smaller and coarser, and M37 nice like a bit of spilled
sugar. M38 and M36 just fit in the same 30x field with the 16mm
Nagler. Also SW of M38 is a cute little asterism of stars i've seen
referred to as the Dolphin.

From the open clusters moved over to Taurus and M1. Not at all bright
but plainly visible with averted vision. Will be better later in the
season when it's higher in the sky. Surprisingly using the UHC filter
the view doesn't really improve.

Last two M objects were galaxies... M77 in Cetus is compact and
bright. There are also quite a few other galaxies nearby but i didn't
bother trying to find any of them considering the mediocre sky
conditions. The only failure of the night was M74 in Pisces. It's just
not there. I did check M33 almost directly overhead in Triangulum.
Large and quite bright actually.

So to sum up my Messier survey with the TV76 from home i've only
failed to see 5 objects, all galaxies... M74, M91, M98, M108 and M109.
All of them are visible from darksky sites with the TV76, but so far 5
are out of reach from my backyard.


-Florian
Stargazing.com

Interesting post. I, too, went out at 4:15am from my home in NoCal and had
about the same results. Spent many minutes looking at M1 with a variety of
eps (80-200x on my 8" SCT), with and without a UHC filter. It was there
with direct vision (8" aperture helps), but not very impressive. I thought
maybe perhaps it was moisture in the air, although I could see a diffraction
ring on most 3rd mag stars. Guess looking through ~2.5x the air you would
at transit is the big culprit. You'd certainly think by 4am there would be
calm air and as dark a surburban sky as you're going to get!

On Sat, 28 Aug 2004 19:20:49 GMT, "Florian"
wrote:

Date: Saturday early morning, 28-Aug-2004
Location: Backyard, Palm Springs, California
Equipment: Tele Vue 76 (3" f/6.3) refractor

I always like to visit (or rather revisit) the Messier catalog with a
new telescope. I've had the Tele Vue 76 since February and only have a
few M objects i've not yet seen from home. Having a very small window
of darkness early this morning between moonset and twilight i got up
about 3:45am and went out in the backyard with the TV76. Skies don't
seem as dark as they had been earlier in the week and there is still
some glow over the mountains to the WSW from the recently set moon.

Started with the open clusters in Auriga... M38 with NGC 1907 just to
its south, M36 smaller and coarser, and M37 nice like a bit of spilled
sugar. M38 and M36 just fit in the same 30x field with the 16mm
Nagler. Also SW of M38 is a cute little asterism of stars i've seen
referred to as the Dolphin.

From the open clusters moved over to Taurus and M1. Not at all bright
but plainly visible with averted vision. Will be better later in the
season when it's higher in the sky. Surprisingly using the UHC filter
the view doesn't really improve.

Last two M objects were galaxies... M77 in Cetus is compact and
bright. There are also quite a few other galaxies nearby but i didn't
bother trying to find any of them considering the mediocre sky
conditions. The only failure of the night was M74 in Pisces. It's just
not there. I did check M33 almost directly overhead in Triangulum.
Large and quite bright actually.

So to sum up my Messier survey with the TV76 from home i've only
failed to see 5 objects, all galaxies... M74, M91, M98, M108 and M109.
All of them are visible from darksky sites with the TV76, but so far 5
are out of reach from my backyard.

Nice report, contrasing dark with regular skies.

This is what has always bugged me about Messier object brightness
estimations. I've always found M-76 to be readily visible, even
offering detail (some) in an 8" scope under mediocre skies.
But, M-74 has always appeared to be more difficult to me,
yet some guides mention M-76 as dim.
-Rich

This is what has always bugged me about Messier object brightness
estimations. I've always found M-76 to be readily visible, even
offering detail (some) in an 8" scope under mediocre skies.
But, M-74 has always appeared to be more difficult to me,
yet some guides mention M-76 as dim.


Hi Rich,

This is my log entry from July 18 for M76...

This is one of the faintest Messier objects and can be difficult=20
from the city. Checking the field at 30x with the 16mm Nagler i=20
didn't see anything. Switching to 48x with the 10mm Radian i can=20
just see the planetary as just barely brighter than the background=20
skyglow. The surprise was when i put the UHC filter on the=20
Radian... Wow! The neb just popped into view! The filter made=20
such a difference in contrast that what was before a marginal=20
object became bright and very easy. I'm not a huge fan of filters=20
but once in a while they can do impressive things!

I didn't try the UHC filter for M74 this morning as it shouln't really
make a difference for a galaxy.=20

-Florian

On Sun, 29 Aug 2004 03:25:13 GMT, "Florian"
wrote:

This is what has always bugged me about Messier object brightness
estimations. I've always found M-76 to be readily visible, even
offering detail (some) in an 8" scope under mediocre skies.
But, M-74 has always appeared to be more difficult to me,
yet some guides mention M-76 as dim.


Hi Rich,

This is my log entry from July 18 for M76...

This is one of the faintest Messier objects and can be difficult
from the city. Checking the field at 30x with the 16mm Nagler i
didn't see anything. Switching to 48x with the 10mm Radian i can
just see the planetary as just barely brighter than the background
skyglow. The surprise was when i put the UHC filter on the
Radian... Wow! The neb just popped into view! The filter made
such a difference in contrast that what was before a marginal
object became bright and very easy. I'm not a huge fan of filters
but once in a while they can do impressive things!

True. I remember seeing good detail in the Veil Nebula in an 11"
from light polluted skies, but only with a UHC or O3.

Richard wrote in message . ..

I've always found M-76 to be readily visible, even
offering detail (some) in an 8" scope under mediocre skies.
But, M-74 has always appeared to be more difficult to me,
yet some guides mention M-76 as dim.

Yes, I agree with all that. The only case where M76 might be
harder to detect than M74 is if you're using very low power,
in which case M76 will be hard to distinguish from a star.

As with all other planetary nebulae, the faintness of M76 is
often exaggerated by people who use photographic rather than
visual magnitudes. Planetary nebulae are always easier to see
than the photographic magnitudes suggest because they emit a
very large portion of their light near the peak sensitivity
of the human eye.

But even using visual magnitudes, M76 is *still* one of the
faintest Messier objects in terms of total (integrated)
brightness. But it is also exceedingly small, giving it one
of the highest surface brightnesses of any Messier object.
So as you say, M76 is quite easy to see in an 8" scope even
under quite severe light pollution -- and even shows nice
structure. An 8" scope pulls in enough light so that M76
is easy with direct vision, just like a mag 11 star.

With a small scope, the story's different. There, the total
light of M76 is none too bright to start with, and serious
light pollution can make it invisible for exactly the same
reason that mag 11 stars become invisible.

M74, on the other hand, has both low integrated brightness
and low surface brightness. The low surface brightness makes
it a real challenge under light pollution regardless of how
big your scope is.

- Tony Flanders