Leo 1

Okay so I am working my through the LGGN pin from the Astro League. I have been researching this object because it is the most distant satellite galaxy of the Milky Way.

So Cosmic Challenge lists this as a challenge object for monster scopes, Sue French's lovely Deep Sky Wonders book doesn't list it nor does NSOG. I have found a few references on blogs, one Stephen Waldee makes me think this one might be doable. Also David Kneisly on CN has some positive results, but I think his sky is better then mine.

So anyone used a smaller scope on this with any luck? How does it compared to IC 10 and IC1613?

Preston,
I did barely see it with a 10" in 1989 and needed rocking of the telescope and averted vision to see it. More recently, with a 20", still faint. The last time I was out dark sky observing, it was the end of November 2013 (welcome to the East Coast weather patterns!) and IC-10 was seen with a 22": "Magnitude 10.4 but very spread out. The picture in S & T was helpful showing a right triangle leading right to it." Did not have as good luck with IC-1613: "Negative at all combinations of filters and tricks. Very spread out and thin. Can see the surrounding trapezoid asterism and other star patterns." With the last 2, I also used a Galaxy Contrast Enhancement filter from Omega Optical. Seems to help quite often and is one of three filters in a filter slide.

Leo I is upon us now and the others I would not even attempt till they are far higher. My 18" in mag 21.3 skies was just able to make out only the brighter sections of Ic10 and finder chart required but that is too low nowdays anyway. I can say that a view through a friend's 28" reviels Ic10 well but still not so obvious that it jumps out at you, you have to have a good idea of where it lies in the field. Ic 1613 is worse because there is not a concenrated section like Ic10. Both require good finder chart and very dark skies as well.

The Leo I problem is that it is next to a blazing hot Regulus so that poses some challenge if your scope is not well baffled maybe. I have no observations of any of these in smaller than my 18 so sorry on that point, cannot help. I will be trying for it again maybe next new moon. If you get a really dark night with Leo I straight up is the only hope in the sort of aperture you are discussing. Sky darkness is a big factor and move the scope and so on. If Regulus were not so darn near it would help as you could use wide enough field to maybe detect Leo I easier.

The smallest scope I've seen Leo 1 with is my 6" dob. What it requires is clean optics and clear sky. You don't want any light scatter. Look at images so you can be very sure of the star field and then be able to move Regulus out of the field.

How it compares to the other two galaxies you mention I've never considered. First of all I've never tried for IC 10 with my 6" but under a reasonably dark sky didn't find it too difficult with my 12.5" and easy with my 20". IC 1613 I can't ever recall trying for. Cetus from my location on the coast of SW Canada and looking across the ocean isn't the best constellation to be observing in.

Perhaps this article will inspire you. http://freescruz.com/~4cygni/astro-app/essays/Leo1.htm You will only know you won't succeed if you don't try or give up trying.

Bill

Preston,

smallest aperture with positive success was 4" on Leo I (UGC 5470). This was a very difficult observation - Leo I was visible as a bump out of the glow of Regulus. I observed with 18x (AP 5,5mm)

As it was said a perfect and dry sky with good transparency is absolutely necessary that the scatter around Regulus is as small as it can be.

IC 1613 and IC 10 are much easier with small aperture than Leo I. I could observe these two galaxies several times with 4" aperture class telescopes. I wrote down these observation in an own project "Local Group". Unfortunately it is in German but google translator may help.

Take a look at this thread.

http://www.deepskyforum.com/showthre...96-Leo-I-Dwarf

Preston,

Sorry for the late reply.

I covered Leo I when I was writing Small Scope Sampler, hence it's in the first book, Celestial Sampler. Here's the text:
Next we'll move to the end of the Sickle's handle marked by Regulus, Leo's brightest star. The Local Group dwarf galaxy Leo I sits just 1/3º north of Regulus, and while Regulus makes Leo I easy to locate, its glare makes the galaxy difficult to see. Leo I is large, but it has a very low surface brightness and is a challenging target for any scope. It is thought to be the most distant of our Milky Way's known satellite galaxies.
To make the effort a bit easier, choose an eyepiece that will leave Regulus out of the field of view. With my refractor at 87x, Leo I is very faint, slightly blotchy, and has a few faint stars superimposed. The orientation appears to be east-northeast to west-southwest with dimensions of about 8' x 5.5'. When I observed this object with Lew Gramer at the Winter Star Party, Lew thought he could see more of the galaxy beyond the area I described. I tried to detect this for quite a while, finally conceding that it was just a "maybe" for me. If you have a lot of trouble spotting Leo I, console yourself with the thought that this dim galaxy wasn't even discovered until 1950.

Clear skies, Sue

Last night using 12" lightbridge dob and 8mm Delos in a ParaCorr Leo I was visible in mag 21.5 skies at meridian. At 1753mm focal length the 8mm Delos offers 219x with a 27' FOV so regulus could be 10' outside of the field with Leo I just a bit off of center.

The slightly blotchy large object elongated perhaps 1.3 or more along E-W had non-distinct edge definition but was unmistakably present with movement of the scope.

I would have to agree that to see this in 6" or less would require the best of transparency and very good eyes on a very dark sky. I may try that in my 18" this season as I have a 6.2" primary mask I use sometimes for planetary and seeing estimations. (One of the key 'official' seeing estimation scales for observatories is with 6" refractor). My eyes may not be able to see Leo I with 6" is my guess but I do know people who have 1/2 or better 'limited mag' and they may just be able to see it in 6" ideal conditions.

I was very impressed by the contrast in a Takahashi 5" that my friend owns. It might be worth trying to attempt it again from TSP if he is willing to let me look at Leo-I through his scope. I wouldn't be surprised if I did see it.

I think the key to these low surface brightness objects is good contrast and dark skies. Leo-I was fairly easy in my 18" from TSP skies.

Regards
Akarsh

Also, how much harder is Leo-II compared to Leo-I? Leo-I was definitely visible from the usual place I frequent for observing (which is not as dark as TSP, but you can still see the Gegenschein quite easily on the good nights), but I tried Leo-II for a long time and hardly saw it.

Are TSP skies likely to show me Leo-II with an 18"?

Regards
Akarsh

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Originally Posted by akarsh

Also, how much harder is Leo-II compared to Leo-I? Leo-I was definitely visible from the usual place I frequent for observing (which is not as dark as TSP, but you can still see the Gegenschein quite easily on the good nights), but I tried Leo-II for a long time and hardly saw it.

Are TSP skies likely to show me Leo-II with an 18"?

Regards
Akarsh

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Akarsh,

Leo II is going to be a lot tougher then Leo I. I went looking on the net and found a few sites where people have observed it, even with a C11 (with goto/ tracking). Also found a negative observation with someone using a C14. I say go for it and see what happens. Alvin Huey has a website with a nice PDF of local group galaxies.
http://www.faintfuzzies.com/Download...ngGuides2.html

Perhaps the C14 was not properly collimated and/or the sky was not really dark or seeing/transparency were bad it may have accounted for the negative observation. Need a sky darkness and transparency assessment along with aperture.

I remain highly sceptical of a 5" scope of even the finest quality to absolutely able to detect Leo I. As a minimum it should be verified by a fellow observer of similar or better deep sky threshold abilities. Although I have fairly good low light detection myself I know of several others who have at least a half mag better detection ability than myself (lucky sods!). Maybe those people could see it in a 5" scope, I doubt I could. Oh to have 'young eyes'.

I have just pulled out my Celestial Sampler book (a must have for everyone frankly, well done Sue!). Sue states her Leo I observation above as a 'maybe' and I do trust Sue by the way as an 'honest' observer. What was missing is the aperture of her refractor. I suspect it was in the 5" range? I am sure she has stated that numerous times but I don't recall. Thanks

Quote:

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Originally Posted by Marko

I have just pulled out my Celestial Sampler book (a must have for everyone frankly, well done Sue!). Sue states her Leo I observation above as a 'maybe' and I do trust Sue by the way as an 'honest' observer. What was missing is the aperture of her refractor. I suspect it was in the 5" range? I am sure she has stated that numerous times but I don't recall. Thanks

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On the C11 the guy was Stephen Waldee, who claimed he saw it. The negative was Jay Reynolds Freeman. The Waldee guy has an extensive blog.
http://freescruz.com/~4cygni/astro-app/essays/Leo1.htm

I observed Leo 1 last week using a 12"F5 Dobson. The satellite galaxy was easily visible using averted Vision, even the Elongation was evident.

The sketch:
http://www.licht-stimmungen.de/01_su...1_03_2014.html

I haven't seen Leo 1 yet, but I've suspected IC 10 in my 63mm Zeiss Telemator and seen it without any difficulty at all in a 6" f/8 achromat at 40x. In my 12" f/5 Lightbridge, I can begin to see mottling. IC 1613 has remained completely invisible to me.


Clear skies!
Thomas, Denmark

I have yet to see Leo I myself. It is on my list for my forthcoming visit to a very dark site (Lysos) in three weeks time. IC10 I have suspected on an extremely clear and transparent night at another dark site back in 2009, with my old 12" dob. But IC1613 I have managed to observe, with three different scopes. First time it was with my old 12" in an ultra-clear night in September 2009, it was just a barely perceptible brightening of the sky that seemed to move when the scope was moved. It was too ill-defined, and it took me a long time to persuade myself that I have seen it. My second time was with a 6" achromat from the very dark skies of Lysos, in August 2013. Again, it was nothing more than the most subtle brightening above the sky glow, and it was 70% averted vision - 30% direct glimpses. Best sighting though was with my 18" in October 2013 again from the dark site at Lysos. IC1613 had a defined shape and even its brightness profile showed some variation, as can be seen in the attached drawing (it was fainter than the sketch implies, but it would be impossible to record with lower contrast!). I believe that IC1613 is possible even in a 4" scope, as Steve O Meara describes in his Caldwell objects book, but it will require perseverence and a great night. 12 or more inches are definitely much more useful for this object...

Attachment 1156

I've seen both IC10 and Leo-I with my 18" from reasonable (Bortle 2 ~ 3) skies. While Leo-I was difficult the last time I observed (when I failed in observing Leo-II), but was "obvious" at TSP, the way I recall it. Of course, these things are subjective, so my "obvious" was probably compared to my expectations back then, which have thereafter changed rendering the current view "difficult". But it was definitely there.

That was the 105mm protoype of the AP Traveler, which is what pretty much everything in Celestial Sampler was done with unless otherwise stated. Thanks for the kind words, Sue

Quote:

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Originally Posted by Marko

I have just pulled out my Celestial Sampler book (a must have for everyone frankly, well done Sue!). Sue states her Leo I observation above as a 'maybe' and I do trust Sue by the way as an 'honest' observer. What was missing is the aperture of her refractor. I suspect it was in the 5" range? I am sure she has stated that numerous times but I don't recall. Thanks

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I've seen it with my old 12", with good transparency, very good seeing (rare to have good transparency AND good seeing here!) and a naked eye limiting magnitude of 6.0:

UGC 5470 (Leo 1), galaxy in Leo - Next to, and just north of, Regulus this is easy to find but not so easy to see. It is very dim oval glow, barely seen against the sky. 12” f/5 Dob 101x, 190x. 6th April 2011

I have tried this one, but no luck yet. I guess I need to spend some time with it. Transparency is typically not the best around here, though last night it was good. I just forgot it as I was checking out the four NGC's around 4860 in Leo's hindquarters.