Faint galaxies/24"

[jetstream]

Can I bore everyone with another report?

The sky was good with structure in the MW and with M8 etc easily naked eye down south. I wanted to pursue Draco after seeing a nice galaxy near the Catseye nebula.  This scope seems to do well so far on galaxies so I put a few into the Sky Commander to see what I could get.

First a triple set consisting of NGC 6419 @ 15.5 mag, .95 arcmin, NGC 6420 15.5 mag, .45 arcmin and NGC 6422 15.1 mag .56 arc min. All three were bagged with NGC 6420 flicking in and out of averted vision. I was using the Nikon HW 14mm, good for this but not that good. Next time an ortho comes out, these galaxies sit in a triangle of 3 mag 8 stars for reference.

I had a failure on the NGC 6456 group with it being 15.7 mag and .34 arc min. At least I'm defining the limits so to speak.

Over to a great planetary- the Magic Carpet nebula- NGC 7027- what color! a very bright green in the 14mm HW with a hint of asymmetry at this lowish mag- next time more power goes on it.Man is it bright,small but bright. After galaxy observing a bit more relaxed sky cruising is nice so over to M24, a special favorite and what do you know? B93 and B92, 2 beautiful dark nebs stood in stark contrast to all those stars.

One last view...I picked M101 to finish the night- hey- who put all those faint galaxies near it?! I must have chosen not to see them before lol! Seriously though NGC 5485 @ 12.2 mag 1.6 arc min very easy and the faint NGC 5484 15.6 mag .34 arc min bounced in and out of averted with NGC 5486 held in direct at 14 mag and ,49 arcmin. NGC 5473 and NGC 5477 were there too along with the always bright NGC 5474.

So anyway, that was my night, time for bed. The scope used was the 24" with 20mm lunt HDC and the Nikon 17/14mm HW. Filters were the Lumicon UHC and OIII.

[John]

Very interesting report with your new big gun Gerry

From my back yard my 12 inch gets me down to mag 14.7 (thats the best so far) so it sounds like you are getting a full mag fainter with double the aperture and your darker-than-mine skies. And I suspect there is a wee bit more to come from your 24 incher !

 

[Piero]

Great report, Gerry! 

I also think that the cannon can go deeper. Any plan for Docter+VIP?

[jetstream]

Yes, the Docter and orthos will be used as well as the 10mm BCO which is a good copy. I was out in the sun yesterday and had issues dark adapting- it took me much longer than normal. These computer screens don't help and neither does the Sky Commander 's green screen...

The Nikon HW/barlow at 14mm is acceptable but not optimum and the 10mm BCO will go a hair deeper than the Docter as tested in the 15" .  One thing is for certain, the size of the galaxy impacts its viewability and much higher mag is needed, where the f4 allows for a nice increase here. I have an excellent copy of the 7mm KK ortho for 357x. This one got me the central star in the ring nicely in the 15".

As far as magnitude limits what are the thoughts about point sources vs extended objects vs limiting magnitude?

Moore has a more conservative rating for point sources as shown in the chart.

"

Limiting Magnitude

Aperture (inches)	Aperture (mm)	Limiting Magnitude (method 1)	Limiting Magnitude (method 2)
1/4	6	7.5	6.3
.31	8	8.2	6.9
2	50.8	12.2	11.0
3	76.2	13.1	11.8
4	101.6	13.7	12.5
5	127.0	14.2	12.9
6	152.4	14.6	13.3
8	203.2	15.2	14.0
10	254.0	15.7	14.5
11	279.4	15.9	14.7
12	304.8	16.1	14.8
14	355.6	16.4	15.2
16	406.4	16.7	15.5
17	431.8	16.8	15.6
18	457.2	17.0	15.7
20	508.0	17.2	16.0
22	558.8	17.4	16.2
24	609.6	17.6	16.4
30	762.0	18.1	16.8
32	812.8	18.2	17.0

Edited June 28, 2019 by jetstream

[Stu]

Keep them coming Gerry! Great to have you posting regularly again.

I'm sure there is plenty more to come. I wonder if it is worth using some neutral density film over the Skycommander display if it is too bright?

[jetstream]

1 minute ago, Stu said:

Keep them coming Gerry! Great to have you posting regularly again.

I'm sure there is plenty more to come. I wonder if it is worth using some neutral density film over the Skycommander display if it is too bright?

Thanks Stu, the weather is finally co operating.

I must do something, including shutting it off if needed- maybe an orange film over it to turn red? Another no no for me is the computer screen with its polarized light- this wrecks my eyes for a very long time, as well as the LED TV.

 

[Stu]

7 minutes ago, jetstream said:

Thanks Stu, the weather is finally co operating.

I must do something, including shutting it off if needed- maybe an orange film over it to turn red? Another no no for me is the computer screen with its polarized light- this wrecks my eyes for a very long time, as well as the LED TV.

 

That's good news.

A bit of experimenting needed perhaps to see what works best. I assume you have dimmed it as far as it goes in the settings?

[estwing]

Lovely read Gerry....I feel the ap fever is upon me!

[jetstream]

15 minutes ago, Stu said:

That's good news.

A bit of experimenting needed perhaps to see what works best. I assume you have dimmed it as far as it goes in the settings?

yes, its on the lowest setting and I love this thing already. Even with all my ducks in a row I'm not so sure I'll exceed 16mag on an extended object by much... with the 15" I don't think I exceeded Moores magnitude in the chart on an extended object.

[jetstream]

6 minutes ago, estwing said:

Lovely read Gerry....I feel the ap fever is upon me!

Thanks Calvin!

Just curious for reference, how faint of galaxies can you guys go on dark sites?  Has anyone gone over 16mag on one?

[estwing]

15 occasionally...Mapstar has had success with higsons 55.

[jetstream]

10 minutes ago, estwing said:

15 occasionally...Mapstar has had success with higsons 55.

Thanks so much Calvin, the voice of experience means a lot. I just looked up Hickson on Vogels site- I can see where magnitudes get confusing- Vogel lists blue and red magnitudes and judging from the red I can see an opportunity for 4 of them-"a" and"b" should be do able here with luck, maybe more. Simbad lists UGC 6514 (Hickson 55) as 15.2 mag-maybe for the object as a whole.

If you guys have any suggestions for me pass them on will you? Thanks, Gerry

[estwing]

One of the best and challenging books for big dob owners is the peculiar galaxies book available from FLO. very interesting articles and gives descriptions from observers using 18,20,22,24 even 26 and bigger scopes.

I highly recommend it Gerry.

[estwing]

Yes mags do vary in different books,websites and even on sky safari!

[estwing]

You'll be in PGC territorys along with PALs!!!

[jetstream]

2 hours ago, estwing said:

One of the best and challenging books for big dob owners is the peculiar galaxies book available from FLO. very interesting articles and gives descriptions from observers using 18,20,22,24 even 26 and bigger scopes.

I highly recommend it Gerry.

Thanks Calvin, I'm going to get it. Tonight looks very good! Possibly better than the last couple of night, we'll see. Maybe I'll dust off the 10mm BCO and try Hickson 55 its nice and high.

[Littleguy80]

Fantastic report, Gerry. Your influence on me always shows through when I reach for the Orthos on fainter targets! 

The Interstellarum Deep Sky Guide is a great book and has a definite big scope bias. Lots of sketches of targets at very high power in big scopes. Examples of the cat’s eye and Hickson 55 below.

Edited June 29, 2019 by Littleguy80

[estwing]

Yeah....those D and E take some teasing 😳

[jetstream]

7 hours ago, Littleguy80 said:

The Interstellarum Deep Sky Guide

Thanks Neil, I need resources such as this- I'm a bit lacking in the info dept.. had a great night last night and the ortho worked! M57 central star easy with the 10mm BCO at 249x, among other things. Hickson 55 was behind the trees though unfortunately.

[jetstream]

7 hours ago, Littleguy80 said:

The Interstellarum Deep Sky Guide

Where did you buy it Neil, it seems very expensive here...

[estwing]

I got urano off FLO good details and the field guide is full of information. 

[estwing]

[estwing]

These are from the peculiar atlas

[jetstream]

1 minute ago, estwing said:

Thanks Calv- what red torch do you guys use at night?

[estwing]

Great notes at the bottom also..