Object of the Week November 17, 2013 - The two Tadpoles of IC 410 in Auriga

Simeis 129 and 130, part of IC 410

Auriga

RA 05 23 08
Dec +33 28 40

Type: Dense Globules in Emission Nebula

Despite being not listed in either the Messier catalog or the NGC, IC 410 is a very conspicuous and bright emission nebula in Auriga. With UHC or OIII filter, it is distinctly visible from my suburban backyard using my small 4.5" reflector as a faint smudge. With larger telescopes, it is an interesting object with a horseshoe shape plus internal dark and bright structure and a central cluster of new stars.

The Tadpoles in IC 410 are so-called globules, which may be the birthplace of new stars. These globules are eroded by the radiation of the central star cluster similar to the Pillars in M16. The side of the globules that faces the cluster is excited and is visible as a bright rim.

http://www.reinervogel.net/exotic/images/IC410.jpg

Despite there are many beautiful pictures of these tadpoles, as for instance by Richard Crisp here as narrow band image, I did not find any observing reports of them when I tried to observe them for the first time about 6 years ago. In February 2008, I finally succeeded in observing them at the first try. In the meantime, they even made it into Sue French's Deep Sky Wonder column in Sky and Telescope (01/2010, p65), where I found out that they even bear designations of their own, Simeis 129 and 130.

http://www.reinervogel.net/exotic/im...410tadpole.jpg

The brighter of the two globules, bearing the name Simeis 130 and being the left one in the close-up left, is relatively easy and well within reach of a 12". It reacts well to filters and in particular to the UHC filter, appearing as a small extended brighter patch with a superimposed group of three very faint stars.

The second tadpole (upper right, Simeis 129) is more difficult, partly also due to the star superimposed on the bright rim of the globule, but well within reach of my 22" using filtering.


My first observation in 2008 was with my 22" under pretty murky skies, maybe mag 5.5 at the city border of Freiburg, Germany. Nevertheless, the brighter one of the globules could be observed easily with UHC using averted vision. The OIII and H beta filters were not as helpful as UHC. Since then, I have revisited IC 410 and the Tadpoles numerous times, but not for the past two years. It's therefore on my list as well for the next clear nights.

Reiner,

I tried both globules with my 16" a few years ago. With 140x (AP 2,9mm) + UHC both were visible. I noted a very good response on a UHC filter with a distinct blinking effect. SE tadpole was much easier than the NW and was visible as a round, diffuse patch of light. I could only pick up the central bodies of the globules, not the fainter extensions.

I was just going through my notes looking for inspiration for my next OOTW and came across two observations of IC 410 I'd forgotten about with my 28 inch f4:

"Lots of nebulosity seen at 105x and the OIII filter, I was surprised how much I could see even though the 3rd quarter Moon rose during the observation. I was looking for the Tadpoles but not sure I saw them but i did see two definite streaks. 20.96 SQM"

"I saw the Tadpoles pretty easily with the OIII at 105x and added them on my January 17 2009 sketch (the first observation above). 21.80 SQM but partly cloudy"

And here's the rough sketch:

Attachment 978 Attachment 979

Dang it, I wish I had checked in on DSF prior to going out last Sat night (it was very nice night).
This looks like a fun one with the 18".
I just checked and my astrophoto of flaming star as well as IC410 just catches these two in far upper left here
http://astrospotter.zenfolio.com/p69...dd87e#he9dd87e

Great object duo Reiner along with a very nice write-up! Thanks!

I took the chance last night to re-observe the tadpoles with my 22". Conditions were so-so with a thin high cloud layer and a limiting magnitude below 6.0. I therefore only tried the brighter one of the two.

Visibility depended considerably on the exit pupil. With my 13 mm Nagler (exit pupil 2.9 mm), the core of the brighter globule was well visible as a faint round patch superimposed on one of a group of faint stars using either OIII or UHC filtering. No tail was visible. With my 7 mm Nagler (ep 1.6 mm), which I routinely use for such small objects, it became very difficult to resolve this round patch from the stars and the background nebulosity of IC 410.

Today's APOD offers a beautiful image of Reiners OOTW.....

http://apod.nasa.gov/apod/ap140109.html

Hi

I picked this object from OOTW (so, thank you, Reiner), and observed it last night. I hadn't read the other observation reports, and I'm glad to know that I was looking at the right thing, because I was under the impression that the tails would be visible given that they are so bright in the photographs. Of course, I should know by now that it doesn't correlate with observability. I could see both globules, but no tails.

The nebula itself is beautiful with the dark "hole" more prominent in OIII than in UHC per my observations. My favorite power was about 100x for the entire nebulosity, and about 150x for the tadpoles. OIII performed better in my experience.

Observation was with 18" f/4.5 Obsession under Bortle 2-ish skies.

Regards
Akarsh