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Thread: Large diffuse object 30 minutes from Sirius?

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    Default Large diffuse object 30 minutes from Sirius?



    I hate asking what seems to be a dumb question but can someone here tell me what is the name (or catalog designation) of the large amorphously shaped object, hollowed out in the middle very near to Serius? Since it fits easily inside the TFOV I roughly calculated as 55-minutes across I estimate Its size at maybe 20-minutes by 15-minutes. It appears as an opaque ragged cloud with large outflung tendrils. It stays completely inside the same 55 degree circle as Sirius is roughly centered in.

    Oddly, when I use IDENTIFY with my 6se scope that should single out the nearest such objects in order of proximity, the nearest nebula that comes up is the Orion Nebula, completely skipping over this one in the process.
    Last edited by LoneTree1941; 10-22-2019 at 05:19 PM.

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    Default Re: Large diffuse object 30 minutes from Sirius?

    The Seagull Nebula, IC 2177, perhaps?
    Mary


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    Default Re: Large diffuse object 30 minutes from Sirius?

    IC 2177 and NGC 2327 are possible.

    NGC 2327 and the Seagull Nebula IC 2177
    Scopes: Refractors: Orion ST80 (mods for white light solar), SV ED80 f7 Newtonians: Z12 f5 Catadioptrics: VMC110L, Intes MK66 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binocular Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker III, Vixen Porta II, Celestron CG5, Orion Sirius EQG

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    Default Re: Large diffuse object 30 minutes from Sirius?

    Hi and thanks Mary and not_Frit_Argelander
    Both NGG2327 and IC2177 are nowhere near enough to Sirius. (I checked their ra/dec and they are hours and degrees distant) The object in question is contained inh the FOV along with Sirius (with Sirius a little off center) through a 25mm eyepiece. That’s with my 1500 focal length (1560 with the star diagonal) 6” objective 6se scope. As far as I can tell the True Field Of View of that lens is a little less than 60 minutes. Judging by that the “nebula” is about 20’ by 10’ extending longitudinally out from but near to Sirius.

    At 04:30 (EST) the morning after I made the OP I went to my scope and centered on Sirius. The sky was as clear as it gets in the early morning before dawn (by a couple of hours) with all the ambient lighting and it was clearly visible, as before.

    I checked and anyone who checks a Star chart (Current epoch) with Sirius (Canis Major) marked and the Orion Nebula is straight above it on the same chart (but in Orion) illustrating how a nebula should be marked. You’ll see there’s no similar marking within a degree of Sirius.

    It would be great if someone with good visibility would check that out with their scope and verify.
    Last edited by LoneTree1941; 10-26-2019 at 04:43 AM.

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    Default Re: Large diffuse object 30 minutes from Sirius?

    What scope are you using? What eyepiece? I'm beginning to suspect it's an internal reflection problem with your equipment.....
    Scopes: Refractors: Orion ST80 (mods for white light solar), SV ED80 f7 Newtonians: Z12 f5 Catadioptrics: VMC110L, Intes MK66 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binocular Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker III, Vixen Porta II, Celestron CG5, Orion Sirius EQG

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    Default Re: Large diffuse object 30 minutes from Sirius?

    All that is already stated in my two previous posts
    Please go back and fully read.
    This object moves simultaneously with Sirius (in the eyepiece) so I know that it is not an artifact of the scope but is in fact there.

    It is a Celestron 6se GoTo scope and I set up on solar align and replace planets with stars and then objects come reliably into view during the night (including DSOs) so I know my setup is good.

    During the day, even in full daylight, Sirius (but not the object) is still visible as a bright point of light, centered in the field of view, and I can spot Venus and even Mercury (with some effort) likewise with GoTo even in daylight proving the settings.

    During a previous hazy night the object was not visible but I would expect any nebulous object to be washed out when conditions are poor.

    The problem is, for us right now Sirius does not rise above the horizon until 01:30 so it is inconvenient to check. But being a sometimes (but not always) nocturnal riser, and with my scope set up in front of a large window and inside, I can stroll in and look. Yes the window does open out of the way and does not impinge on the view.
    Last edited by LoneTree1941; 10-26-2019 at 02:40 PM.

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    Default Re: Large diffuse object 30 minutes from Sirius?

    But yes not_Fritz, Sirius is so bright that an internal reflection could develop I suppose. I change lenses but the tube remains the same.

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    Default Re: Large diffuse object 30 minutes from Sirius?

    An edit I made seems to have gotten lost.

    Near Sirius is NGC 2296 a 13th magnitude nebula about 52' away. NGC 2296

    In the opposite direction is Berk 25 an open cluster at about the same distance, a little further at 58'.

    That's it. I suspect that when you slightly offset Sirius from the center that you get an internal reflection in the OTA. Also, observing with the telescope indoors can introduce ghost images from ambient lights.

    I'd suggest that you make / buy a dew cap extension. Black matte construction paper is light and it is easy to fit around the front of your OTA. This would eliminate environmental stray light but not ghosting in the OTA from Sirius itself.
    Scopes: Refractors: Orion ST80 (mods for white light solar), SV ED80 f7 Newtonians: Z12 f5 Catadioptrics: VMC110L, Intes MK66 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binocular Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker III, Vixen Porta II, Celestron CG5, Orion Sirius EQG

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    Default Re: Large diffuse object 30 minutes from Sirius?

    Another thought ...

    Are you sure you are looking at Sirius? If you happened to look at Alnitak instead of Sirius, what you saw could be the Flame Nebula. I am not saying this is what you are seeing, but you could try to center on Alnitak and have a look at it, and check if it looks familiar. How dark are your skies (in Bortle scale)?
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    Default Re: Large diffuse object 30 minutes from Sirius?

    not_Fritz had it right in post#4; when I put on my dew shield and next observed it was still there but it changed shape considerably. It’s like i said in the opening line of the OP: “a dumb question...”
    Thanks for bearing with me!

 

 
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