Galaxy Challenge

glenc (Glen) · #1 30-08-2006, 01:07 PM

Sir John Herschel searched the southern sky from Cape Town between 1834 and 1838. The faintest southern galaxies that he found with his 18.5" telescope are listed below.

There are 24 galaxies in the list, all south of dec -30 deg.
NGC 88 has the faintest mag.

How many can you see?
A 10" might show some of them, a 12.5" should show all of them.

NGC Const Vmag
31 Phe 14.1
87 Phe 14.4
88 Phe 14.7
159 Phe 14.0
427 Scl 14.2
549 Scl 14.6
572 Scl 14.2
644 Phe 14.1
698 For 14.0
727 For 14.1
729 For 14.1
754 Eri 14.2
1660 Cae 14.0
1669 Dor 14.0
1998 Pic 14.3
2200 Pup 14.2
2883 Pyx 14.4
5108 Cen 14.2
7178 PsA 14.0
7278 Tuc 14.5
7299 Gru 14.1
7355 Gru 14.3
7657 Tuc 14.1
7658 Gru 14.3

glenc (Glen) · #2 31-08-2006, 01:24 AM

Here is an image of NGC 88, John Herschel's faintest galaxy.

http://www.ngcic.org/dss/n/0/n0088.jpg

Thanks to Bob Erdmann at ngcic.org and the DSS.

ballaratdragons (Ken) · #3 31-08-2006, 01:45 AM

they are ALL at mag 14's

Thanks for the list Glen. I have copy/pasted it

A searching I will go, a searching I will go, hi-ho the Dairy-o, a searching I will go!

glenc (Glen) · #4 31-08-2006, 02:07 AM

Have fun. Its cloudy up here.

astroron (Ron) · #5 31-08-2006, 10:54 AM

I have printed of the list and will give it a go in the next few weeks, clouds and rain at the moment plus moon getting brighter every night.
I have images of most of those galaxies ,and what I dont have will get of the deep sky survey or the net.
A good project for the 16"

glenc (Glen) · #6 10-09-2006, 03:50 AM

William Herschel calculated that a new speculum mirror absorbed 33% of the light and hence it reflected 67%.[1] Aluminium mirrors reflect 89% of the visible light.[2] This means Herschel's 18.3” had the same magnitude limit as a 15.5'' aluminium mirror assuming there was no secondary in Herschel’s telescope. So todays 16" should show all the faintest Herschel objects but may not resolve as well.

[1] The History of the Telescope. King p. 137.

[2] King p. 382.

astroron (Ron) · #7 10-09-2006, 02:13 PM

Quote:

Originally Posted by glenc

William Herschel calculated that a new speculum mirror absorbed 33% of the light and hence it reflected 67%.[1] Aluminium mirrors reflect 89% of the visible light.[2] This means Herschel's 18.3” had the same magnitude limit as a 15.5'' aluminium mirror assuming there was no secondary in Herschel’s telescope. So todays 16" should show all the faintest Herschel objects but may not resolve as well.

[1] The History of the Telescope. King p. 137.

[2] King p. 382.

We will also give them a try in Peter Robbins 30" (robbo"s 30) on the 23rd this month at Cambroon Weather permitting.

Argonavis (William) · #8 10-09-2006, 07:18 PM

Quote:

Originally Posted by astroron

We will also give them a try in Peter Robbins 30" (robbo"s 30) on the 23rd this month at Cambroon Weather permitting.

You will get them all then, Ron - if at first it doesn't work, try a bigger telescope!!

astroron (Ron) · #9 11-09-2006, 12:50 PM

Quote:

Originally Posted by Argonavis

You will get them all then, Ron - if at first it doesn't work, try a bigger telescope!!

Bill you could give it a go with your scope and then we could have a a 16"_25"_ and 30" confirmation

glenc (Glen) · #10 16-09-2006, 03:17 PM

Did anyone see any mag 14 galaxies last night?

astroron (Ron) · #11 17-09-2006, 11:51 AM

Hi Glen, I observed on Tuesday Ngc's 31,87/88,159, I tried for the Grus objects earlyer in the night but the seeing was not the best.
I hope to do some constructive observing this next week and will make a proper report, weather permitting, it has been lousy for the last few days

CoombellKid · #12 17-09-2006, 04:50 PM

I've managed to nab a few mag 14 galaxies in Fornax a couple of years ago
with my 8" here in CoomBell. The only way I could really differentiate them
from the surrounding stars, they diddn't appear to be point sources of light
like the surounding stars were. Most more or less appered fuzzy (star like)
dots.

We're looking pretty good out here tonight, This could be a nice lil challenge
to see what and if I can nab. Lynne has been having labour pains for the last
few hours, so it could be a long night.

regards,CS

Rob

astroron (Ron) · #13 18-09-2006, 05:33 PM

The scopes setup and ready to go, there is not a cloud in the sky, so I hope to try for some of the Herschel galaxies tonight

glenc (Glen) · #14 18-09-2006, 05:39 PM

Happy hunting Ron

CoombellKid · #15 18-09-2006, 06:31 PM

Since the missus is about to give birth I've taken the next 2 weeks off
work, we have lovely clear skies here tonight too!!

Was out for a lil bit last night but it turned sad noit long after twilight.
However I wasn't able to pull 7658 out of the sky, but the seeing was
not much good. Not intending on alot success with these objects just
curious.

G' Luck Ron!

regards,CS sunny days

Rob

astroron (Ron) · #16 18-09-2006, 10:24 PM

Just come as it has turned cloudy , I have bagged four tonight in Grus andTuc all quite difficult will give full report later.
I hope the weather clears up.

astroron (Ron) · #17 19-09-2006, 05:52 PM

Managed to get nine last night,before the mist rolled in for the night .
All set up for another try tonight. Report soon

astroron (Ron) · #18 20-09-2006, 05:41 PM

Herschel Galaxy Search report 18/09.06.
40CM f4.5 Truss Newtonian
Seeing 7-10 best 10 TRANS 6-10

Ngc7178. mag 14.0. An elongated elliptical smudge, makes a square with a 8th mag star and a 12.6 double star and a 12th mag star, by putting the 8th mag star out of the field makes it a bit easy er to observe.
Eypieces used 13mm Nagler,21mm teleview plus 2xBarlow.
09:40 ut

Ngc7278.Mag 14.5 is round Very faint very small, looks like a part of a double star,no other detail.
Black cloth over head to get maximum darkness.
A 7.6 star makes this a very difficult object to observe.
5mm Celestron XCel. 10:06 ut.

Ngc7299.Mag 14.1. In same field as Ngc7297, these two galaxies are round seperated by a 13.3 mag star. Ngc7297 is a bit brighter and clumpier but otherwise they are at about similar visibility.
13mm nagler 21mm teleview 2xBarlow. 10:45 ut.

Ngc7355.Mag 14.13.Just hinted at in 13 mm Nagler, no detail,given as non existent in the Rngc catalogue, but the Ngc/ic Project shows a small elongated galaxy .11:15 ut

Ngc7657. Mag 14.1.A small elongated galaxy In the same field as Ngc7650with Ngc 7650 at mag 13.4 the brighter of the two.
A 13,4 mag star is very close by
Averted vision was used to see this galaxy.
13mm nagler. 21mm Teleview 2xbarlow. 12:00 ut

Ngc31.Mag 14.1. a faint oval with 13 mag star north east. Ngc 28 which is star like makes an equatorial triangle. seeing poor.
13mm nagler 5mm X CEL, 13:50 ut.

Ngc87 Mag 14.4.Ngc88 Mag 14.7, these two galaxies are in a sort triangle shaped group of four with Ngc88 star like slightly of centre, just seen with moments of better seeing.
The other galaxies are Ngc89 and Ngc92, all seem to be round with Ngc92 at mag 12.7 the brightest.
13mm Nagler 2x barlow 5mm X CEL. 14:00 UT

Ngc159 Mag 14.0 Faint slightly elongated haze, makes a triangle with a 12.8 and 14.0 mag stars.Seeing poor 13mm Nagler 2x barlow. 14:20 ut

Ngc427. Mag 14.2 Small round galaxy with two 13 mag stars close by,no other detail as the seeing was deteriorating. 13 mm Nagler Close 15:00 ut

glenc (Glen) · #19 21-09-2006, 04:09 AM

Congratulations Ron. A nice report.

Did you look at:
http://www.ngcic.org/dss/n/0/n0088.jpg

astroron (Ron) · #20 21-09-2006, 10:25 AM

Thanks Glen, I observed another eight last night, plus reobserved some of the others, seeing was a bit better,part two report to follow
Ngc87 and Ngc 88 are part a group of four, as I see them Ngc's 87, 89, and 92 make up the triangle with 88 slightly off centre, they where much clearer last night and ngc 88 was seen quite clearly in moments of the best seeing.
I use the images from the NGC/IC project to checkl that I have the correct objects.

I observed this group with Bills (ARGO NAVIS) 25" on Saturday 23/09/06 and confirmed my observations