Dwarf Galaxy IC10 in Cassiopeia

[Moonshane]

Hi all

I noticed this on my map last night and as I have no chance with the 6" I didn't bother looking. I am wondering if this would be observable visually with my 16" dob? Anyone ever seen it? It seems an interesting and very challenging object and unusual too.

Cheers

Shane

[michael.h.f.wilkinson]

I gather IC 10 is rated at mag 10.4, so I should be able to pick it up with my C8 on a clear dark night. According to some back-of-the-envelope calculations, it should be about half the surface brightness of M101. This is easy in the C8. Given that I got IC 342 with the C8 (difficult) and it has a lower surface brightness, the 16" should be OK provided the skies are very dark and clear.

Thans for the tip, I will check it out next time I get a chance.

[Moonshane]

cheers Michael

I'll give it a go from home when my 16" is usable. unfortunately there's a fair bit of LP at home and even M101 was out of reach of my 12" (unless it was just my poor observing skills last time I looked for it). When I look, I'll know I suppose. Looking on a few websites, suggests that for this type of galaxy a UHC or similar filter might help as there are bright Hii regions within the galaxy.

[michael.h.f.wilkinson]

cheers Michael

I'll give it a go from home when my 16" is usable. unfortunately there's a fair bit of LP at home and even M101 was out of reach of my 12" (unless it was just my poor observing skills last time I looked for it). When I look, I'll know I suppose. Looking on a few websites, suggests that for this type of galaxy a UHC or similar filter might help as there are bright Hii regions within the galaxy.

I think an LPR filter (rejecting only a few lines, rather than only accepting narrow bands) would be safer. UHC is usually too strict for galaxies (even starbursts) whereas LPR is less strict and rejects most LP effectively.

[acey]

I've never tried for this object, it sounds an interesting challenge. It was discovered visually by Swift using a 16" refractor; he described it as "a faint star involved in a very large, extremely faint nebulosity, extremely diffuse”.

IC 10 was included in Curtis's 1918 monograph, "Descriptions of 762 nebulae and clusters photographed with the Crossley reflector", described there as, "very patchy, with a number of nebulous condensations. Exceedingly faint."

The total magnitude is misleading; the large size means it is of very low surface brightness and the really important thing is sky darkness rather than aperture. But it has a number of HII regions, therefore a nebula filter might help.

I would say that IC 10 is probably only worth attempting if the sky is dark enough for M101 to be a very easy object. But anything's worth a go.

[Moonshane]

cheers Acey

I agree. one for a star party maybe, with lots of time and people to confirm what you think you are seeing!

[Austin]

IC 10 sounds like a challenge!! I will have to give it a go with my 12 inch as soon as the weather gives me a break!!

[michael.h.f.wilkinson]

I've never tried for this object, it sounds an interesting challenge. It was discovered visually by Swift using a 16" refractor; he described it as "a faint star involved in a very large, extremely faint nebulosity, extremely diffuse”.

IC 10 was included in Curtis's 1918 monograph, "Descriptions of 762 nebulae and clusters photographed with the Crossley reflector", described there as, "very patchy, with a number of nebulous condensations. Exceedingly faint."

The total magnitude is misleading; the large size means it is of very low surface brightness and the really important thing is sky darkness rather than aperture. But it has a number of HII regions, therefore a nebula filter might help.

Precisely, that is why I did a back-of-the-envelope calculation on surface brightness. I got M101 yesterday when the sky was not fully dark, from my back garden, so IC10 might be worth a shot of the clouds buzz off.