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Old 20-12-2015, 09:35 AM
N1 (Mirko)
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Horsehead & Homunculus

Tahmoor, 20 December 2015, 3.00-4.30 AEDT

No cloud
Transparency 8/10
Seeing 6-7/10

10" f/5 GSO dobsonian
Got up out of bed for this, so dark adaptation was as good as it gets.

IC 434/ B33 Horsehead Nebula, Orion
First observation where I can comfortably say that I saw it. 16mm ES 68° with Astronomik H-Beta filter attached, giving 78x and 3.2mm of exit pupil diameter. Found the general area from memory (not difficult) but because I had not remembered the exact position of B33 relative to the foreground stars, there was absolutely no doubt of its visibility when I saw it. Tube nudging improved view but was not essential.

B33 was not visible without the H Beta, however the Flame Nebula (NGC 2024) was seen very well with its branching dark lane a notable feature.

NGC 3372, specifically the Homunculus Nebula, Carina
The two spheres were seen surprisingly well given the less-than-perfect seeing. Pentax XO5, giving 250x and 1mm of exit pupil diameter. A surpirising amount of detail in the greater Carina Nebula even at this small exit pupil.

This was worth getting up for.
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Old 21-12-2015, 12:49 PM
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Paddy (Patrick)
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Very impressive to see the Horsehead in a 10" scope - well done!!
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Old 02-02-2016, 06:21 AM
N1 (Mirko)
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Dunedin, 1 & 2 February 2016, 22.30 - 1.30 NZDT, about 40km west of the city.

No cloud
Transparency 8/10 in light westerlies. Altitude about 500m.
Seeing 6/10

8" f/6 GSO dobsonian
2.4" FS60C f/5.9

IC 434/ B33 Horsehead Nebula, Orion
Detected as a dark notch in IC 434 sans filter using the 8" while in search mode with OTA moving. So it is possible. 25mm Carl Zeiss PL. Exit pupil 4.2mm. Best view through H beta was obtained with a 32mm TV PL at 5.3mm exit pupil, B33's orientation remaining just beyond reach. However the part of IC 434 immediately to the north of B33 was visibly brighter. So that's something to take home. Patrick, the limits imposed by B33 appear to be related to its angular size. Maintain a large exit pupil and even smaller apertures should show it (I'm confident of that now) - until the magnification used is too low. The 32 PL provides 37x in my 8", which is not that much and the lowest power I've used on this object yet. The Horsehead is of a decent size.

N3372 Eta Carinae Nebula & N3532 Football Cluster
24 Pan & FS60C at 4.1mm exit pupil provided the most epic view of the night with both these objects in the same field. After spending much time looking at marginal shades of dark grey, I looked at this vista and found myself just about launched into space.

Large Magellanic Cloud & Tarantula Nebula
28 Edmund RKE & FS60C is a unique experience. With the OTA being small, the entire telescope disappears behind the "floating eyepiece" when used in straight tru mode. The result is a seamless transition between the image and the surrounding sky. The LMC magnified right next to the Milky Way in the same view!

Messier 42 Orion Nebula
Interesting side observation using the 8" with twilight still in progress: the 13mm TV PL smoothie appears to outperform the 13T6 Nag on Trapezium F. The star was immediately and steadily visible in the PL, took a bit more effort in the Nagler.

Last edited by N1; 02-02-2016 at 06:53 AM.
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Old 06-02-2016, 07:22 PM
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Great obs! The Homunculus is a very unique object. Unlike any other nebula I can think of, it appears sharply defined with hard edged detail much like a solar system onject rather than the soft detail typically found in nebulosity.

Interesting obs between the Plossl and Nagler, perhaps the fewer elements in the plossl result in less light scatter offering a subtly cleaner view?
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Old 08-02-2016, 09:26 AM
N1 (Mirko)
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Quote:
Originally Posted by pgc hunter View Post
Great obs! The Homunculus is a very unique object. Unlike any other nebula I can think of, it appears sharply defined with hard edged detail much like a solar system onject rather than the soft detail typically found in nebulosity.

Interesting obs between the Plossl and Nagler, perhaps the fewer elements in the plossl result in less light scatter offering a subtly cleaner view?
Yes the Homunculus is certainly unique. Perhaps the most foreign looking visual target.

Re plossl, I do suspect it has a bit more throughput as it contains a lot less glass. The image generally looked very clean in both and the view in the 13T6 is still spectacular.
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Old 12-02-2016, 11:23 AM
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Tinderboxsky (Steve)
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IC 434 and B33 in Orion

Following Mirko’s observations and comments using an 8” dob I focused on IC434 with my 140mm refractor at the Ben Lomond Star Party last Saturday night to see what was possible.

Ben Lomond provided clear, dark skies at an altitude of approx 1500 metres
Transparency - 8/10
Seeing - 9/10
Vixen NA140SS with 20mm eyepiece giving 40X with 3.5 mm exit pupil.

Initially, nothing was visible given the dominating glare of Zeta Orion. However, moving Zeta Orion just outside the FOV reduced the glare and made a significant difference.

A faint elongated brighter area, too faint to even be described as a haze, was clearly visible. The position of this brighter area corresponded closely to the location of the brighter eastern side of the emission region. The observation did not require averted vision, nor nudging of the scope. Two other observers sharing the scope at the time had no trouble seeing the same brighter area.

We were content with this observation, noting that there was no prospect of seeing any detail or structure. The Horsehead was clearly out of reach at this aperture.

Cheers

Steve.
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Old 12-02-2016, 12:44 PM
N1 (Mirko)
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Interesting report Steve, and a great scope too. Was this without a filter? I use a 1.25" Astronomik H beta. Impressive, IC434 in direct vision. You were most of the way there. 40x should be enough to see the notch (but not which way he is looking).

What eyepiece did you use? I found modern Abbe orthos ideal for dealing with Alnitak's glare at low power. They might also have a slight edge when it comes to transmission.

Ben Lomond looks like my kind of terrain
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Old 12-02-2016, 01:08 PM
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Thanks for your comments Mirko. Yes, I may have been closer to seeing the notch as you describe it than I thought. With the rush of people wanting to observe I did not have the luxury of some quite time to myself to explore further. Hopefully there will be another opportunity.
I don't have any filters, so none on the night. Eyepiece was a Vixen NLP20. I am still exploring a choice of eyepieces for the NA140.
Yes, Ben Lomond was a good choice for the star party. It is the highest accessible altitude available in Tassie with accommodation. We bunked down in the Northern Tasmanian Alpine Club Lodge. The area is marginally above the snow line with old, underdeveloped ski runs. The ski season is short and fickle.

Steve.
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Old 16-08-2020, 09:55 AM
Tropo-Bob (Bob)
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I had my 80mm triplet out early this morning and after a quick tour of 47 Tuc and a few nebulae (Crab, Orion & M78), I decided to see if I could locate some guide stars for the Horsehead Nebula.

I have previously seen the Flame, but never the Horsehead Nebula. Initially, I could not see the Flame with the 80mm. However, as I overcame my mistakes in identifying guide stars, I became better, light adapted and realised that the slight annoying haze that I was seeing was not light cloud, but actually Nebula.

I did not see the Horsehead and I did not have time to set up a more substantial scope, as dawn was approaching.

I will try again tomorrow morning with my Vixen 140mm. I am feeling hopeful, as the Moon will also be less of an issue (below 10%?) and I now know exactly where to look.
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Old 17-08-2020, 06:07 AM
Tropo-Bob (Bob)
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Well, I have accomplished something that I really never thought I would. I found the Horsehead Nebula with my 140mm Vixen, without the aid of a filter. However, I did place a towel over my head to keep out stray light.

I was setting the scope up at 4.20am, before Moonrise. The next part of the plan to use my Panoptic Eps fell apart because the belt star Zeta was in the field of view. I made good progress with a 18mm Radian, before changing to a 15mm Delite (53x). I had thought this would be too high a magnification and too low a size for the exit pupil (2.6mm), but it was the most useful EP.

Other things were also different than I imagined. I had heard the nebula described as a bar with a notch in it. For me, the illuminated background nebula was triangular in shape and varied in luminosity to an extent that it made finding the silhouette difficult. I felt it was like trying to find something that was camouflaged. My first reaction on finding it, was that the head was upside down. I have read that is a common reaction so I felt this verified my sighting. I tried to see which way the ‘head’ was facing. Ha, that was an impossible task.

The brighter, background nebula was an interesting object in itself. After describing it as a triangle, I found traces of it much further away from the Horsehead than I anticipated. However, the thing that was really strange was that I saw it as very light-pink in colour. This does not make sense, as I could barely see it, so how I see it well enough to see its colour? Its large size perhaps, or some stray light from sodium street lights, or was it just the very beginnings of dawn?

I would like to try seeing it again with the appropriate filter, but it is somewhat expensive and I do not need it to view anything else. If someone has one and is kind enough to temporarily loan it to me, please send me a PM.
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Old 17-08-2020, 07:59 AM
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Fabulous result Bob. Persistence and patience has paid off. Great report and thanks for sharing your experience.
You have inspired me to have another try myself. I have not been in a position to try since my report in Feb 2016.
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Old 17-08-2020, 08:47 AM
N1 (Mirko)
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Great outcome, go the 140
Can't wait to point my (yet to be built ) 127 iStar doublet RFT at it.
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Old 18-08-2020, 09:07 AM
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I tried to view the Horsehead again today with what is my light-bucket for this refractorholic: My 8” Edge SCT. It started well, the Flame Nebula was more obvious than yesterday. In contrast, the stars do not look as crisp as yesterday. This confused me a little and as the Horsehead is an extremely marginal object for me to view, I decided to check an image on the computer re the guide stars. Ha, ha, no night vision after that and whilst waiting for it to come good, I could see the faint start of dawn. I had not allowed myself enough time for the task.

Before I had gone inside though, I did note that the surrounding nebula did not appear to have the pinkish colouring, which I observed yesterday. I used approximately the same magnification as yesterday (57 verse 53x), and with my 35mm Panoptic, I also had roughly the same sized field of view. Next time, I really need to use an EQ mount, which will make things a little simpler.

I have been doing this in the morning, because here, it is too difficult in the evening. The morning sky is darker (less houselights polluting the sky) and besides, Orion is in only in the evening during our Tropical Wet Season, when there are often lots of friendly mosquitoes keeping me company.
I can see myself going at 3.00am to a nearby darker site in about 2 or 3 months to observe this a little better. That will be when Orion is overhead.

I have searched a number of images to guide my efforts and selected one that is less overexposed than most. The original which is available at:https://www.reddit.com/r/Astronomy/c...sehead_nebula/
. After this morning season, I have flipped this photo so that its directions are consistent with the view in my scopes, which all have star diagonals. I have then reduced the image to the region of the Horsehead and show the guide stars, which I use. I see 3 stars above the Horsehead that I have not noticed when using the scope. I will attempt to find these, providing they are not too faint. The attached images are still a lot, lot brighter than what I see with the scope.

Thanks for the replies and good luck with your efforts guys. I hope this information helps.
Attached Thumbnails
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Old 18-08-2020, 01:07 PM
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mental4astro (Alexander)
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I have found the Horsie to be a temperamental beast.

Unless transparency is good to excellent it can be very difficult and even impossible to spot it, regardless of aperture and dark sky.

This has been my experience with my 17.5". I have had nights when the Horsie was very easy to see without the use of filters. I've also had nights when it was totally invisible.

Below is my sketch of it with the 17.5" dob. The sketch covers a 2° field of view showing both the Flame and Horsehead. This particular night gave a good view of it. I was also able to make out the crook of the Horse's neck, giving a little more of the horsie appearance seen in photos.

Seeing the Horeshead can be described as an exercise of seeing black on black. The nebulosity the dark pillar obscures is dark in itself. The dark pillar itself is a small back notch that's been cut into this tenuous nebulosity.

One tip I have before attempting to view the Horsehead is gauging the quality of transparency with how much of the LMC I can see. The easier it is to make out the various structural elements of the LMC (the bar, halo, & the Tarantula neb), the better the transparency is and the better chance of seeing the Horsehead. If you are able to make out mottled structures around the Tarantula naked eye, conditions are really good!
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Old 19-08-2020, 02:33 PM
Tropo-Bob (Bob)
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That is a magnificent sketch Alex. It even correctly shows all the faint guide stars, which I have been using.

I tried for a bit of Tak magic on the Horsehead this morning with my 100mm fluorite. I felt close, but no cigar. It was a great morning though with the Andromeda Galaxy being visible to the naked eye. I can never see it like that in the evening, and only on some mornings. The Orion Nebula and Andromeda both looked fabulous, but the air was unsteady and Mars looked fairly ordinary.

Last edited by Tropo-Bob; 19-08-2020 at 02:44 PM.
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