Hiding in plain sight…..

[NGC 1502]

Galaxy NGC 404 must be one of the easiest galaxies to find. It lies immediately north of Mirach, Beta Andromeda. With my 10” Dob at 44x it wasn’t so easy to spot, almost drowned by the glare of bright Mirach. Raising the power using my N11mm for 109x darkened the sky background sufficiently. The galaxy was then easy to see.

Back indoors I checked my Burnham’s Vol 1, page 113. I was shocked to read that NGC 404 is 12th mag!!  I thought surely it’s not that dim, being so easy to see from my town back yard.  An online search said 10th mag which must be nearer the truth.

”Mirach’s Ghost”…..hiding in plain sight😊

Ed.

[josefk]

...and a fabulous object due to it's magical location! IMHO.

Uranometria has it with a visual magnitude of 10.3 and a surface brightness of 12.9.

Cheers

[John]

It's a very nice galaxy to spot once you have had a peek at the M31, M32, M110 trio 🙂

I would say around 10th mag as well. I'm sure I've spotted it with 4 inch scopes. 

[SwiMatt]

2 hours ago, josefk said:

Uranometria has it with a visual magnitude of 10.3 and a surface brightness of 12.9.

That surface brightness sounds a bit too low 😅 Stellarium reports 24 mag/arcsec^2! 

[josefk]

20 minutes ago, SwiMatt said:

That surface brightness sounds a bit too low 😅 Stellarium reports 24 mag/arcsec^2! 

I think SB values can be all over the place in different sources due a little bit to discrepancies in the basic visual magnitude being used but more importantly due a lot to discrepancies in the object size used in the calculation.

I'm a bit fussy about references so in my own notes i have elected to use Uranometria DSFG as THE reference source (rightly or wrongly). It is know to be wrong in places but i like the singularity of it as a source. I sleep well at night 🤣

BTW 12.9 in DSFG would be MSAM and 12.9 + 8.89 = 21.79 MPSAS (brighter than the 24 MPSAS in Stellarium in fact). Though i quoted MSAM I actually use MPSAS myself because it is meaningful (to me) as a value you can compare to a sky reading without mental arithmetic... 

 

[SwiMatt]

18 minutes ago, josefk said:

I think SB values can be all over the place in different sources due a little bit to discrepancies in the basic visual magnitude being used but more importantly due a lot to discrepancies in the object size used in the calculation.

I'm a bit fussy about references so in my own notes i have elected to use Uranometria DSFG as THE reference source (rightly or wrongly). It is know to be wrong in places but i like the singularity of it as a source. I sleep well at night 🤣

BTW 12.9 in DSFG would be MSAM and 12.9 + 8.89 = 21.79 MPSAS (brighter than the 24 MPSAS in Stellarium in fact). Though i quoted MSAM I actually use MPSAS myself because it is meaningful (to me) as a value you can compare to a sky reading without mental arithmetic... 

 

Thanks @josefk! I just misunderstood the units in which you reported the surface brightness as I also always use MPSAS for comparison reasons. My bad!

[John]

I can just about see NGC 404 with my 85mm refractor tonight. It's very faint - practically an averted vision object, but definitely there as a faint glow in the right place. 

I'm finding a 7mm eyepiece (86x) is working the best on this challenge.

 

Edited September 12 by John