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GavStar

Globulars and galaxies

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Posted (edited)

After a good start to the year with several clear nights, the past few weeks have been quite cloudy for me. So when I saw some clear skies this evening I pounced, particularly as there was no moon.

Spring is galaxy season, not a favourite of mine since my LP back garden is not very well suited to showing galaxies.

However, I thought I would have an explore this evening to see what I was missing - quite a lot as it turned out.

I was also pleased to see that some globulars are now coming out to play - some of my favourite DSOs. 

However, I started with Orion, since soon it will disappear until winter. There’s a particularly annoying neighbours tree that blocks a decent part of my south west view, so I set up initially at the back of my garden to get the right angle for Orion. But it moved too quick for me and so I had a look at a few nebulae nearby. As is currently usual for me, I had my phone ready to make a visual record of the observations. 

I stuck to my C11 (with NV monoculars) all evening with the aim of getting some decent image scale on the globs and galaxies.

So first a recent favourite, the monkeyhead. The head filled the fov of the c11 and gave some nice detail.

Then onto the jellyfish which had nice definition.

I tried moving the setup to the front of the garden to get a view round the other side of the annoying tree. Was looking good but by the time I had re set up, a combination of a sole big cloud and time meant that I just missed Orion.

So onto galaxies. First up to get going, my fave set of galaxies m81 and m82. Glorious as always. I managed to get some decent image scale on m82.

Then onto the Leo triplet which just squeezed all onto the fov with the 55mm plossl. Nice set of three, the leo.

Then some new ones for me. Stu has been telling me about the markarian chain. I centred on m86 and went to had a look. A nice lot of galaxies visible but I think these would be more impressive in a big DOB.

So two other galaxies that were recommended to me where the sombrero and the needle galaxies. Both looked great with a bit of image scale. Liked these a lot.

Then to finish up, the globs. I’ve missed these so it’s great to see them reappearing earlier in the evening. The NV resolves m13, m5 and m3 really well going right to the core. I’ve been looking forward to viewing these again and they definitely  didn’t disappoint. I think I even saw the propeller in m13.

It was pretty murky skies in my bit of SW London tonight, but I was pleased with what I saw tonight. Not my usual mix of objects but lots of fun.

 

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Edited by GavStar
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nice report mate and I have enjoyed viewing your images..... Globular clusters are beautiful! They are deffinataly my favourite in the DSO category! From my very limited knowledge I know there some of the oldest stars in the universe but do you know or does anyone else know what makes them 'globular' ? Why are they so tightly packed ? I've only ever seen them in other people's pictures or on tv and I can't wait to hunt some down myself! 

Thanks for sharing

Nathan 

 

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Great report and nice to see the images to go along with it.  Thanks for sharing!

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Fantastic report and images. You covered a lot in one session. Great detail on each object. I was out last night but struggled with a few those on your list. 

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Posted (edited)

Great report , certainly was the night for galaxies and globulars,

Nick.

Edited by cotterless45

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Terrific images of an excellent session. Thanks for posting them !...:happy11:

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Awesome images Gavin! M82 is lovely, excellent detail in there, and I love that dust lane in the Needle.

Makarians Chain probably better with a wider fov to fit more in, and a darker sky.

Presumably these are with the S9? Really nice

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Posted (edited)

Nice one again! You did well to get the dust lanes in the needle and the sombrero. The c11 is performing almost on a par with my 20" from good skies on those galaxies.

:) 

Which filter did you use for the Galaxies?

I think the problem with markarians chain is that the background is too washed out. I think Galaxies will be better with more mag and a blacker background, did you get improvements by turning the gain down?

Alan

Edited by alanjgreen
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The images with NV are just stunning. I love all the galaxy shots. So cool!

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6 hours ago, Stu said:

Awesome images Gavin! M82 is lovely, excellent detail in there, and I love that dust lane in the Needle.

Makarians Chain probably better with a wider fov to fit more in, and a darker sky.

Presumably these are with the S9? Really nice

Thanks Stu, yes first go with the Samsung S9. Initial impressions are good, especially for someone that can only point and click!

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Posted (edited)
8 hours ago, alanjgreen said:

Nice one again! You did well to get the dust lanes in the needle and the sombrero. The c11 is performing almost on a par with my 20" from good skies on those galaxies.

:) 

Which filter did you use for the Galaxies?

I think the problem with markarians chain is that the background is too washed out. I think Galaxies will be better with more mag and a blacker background, did you get improvements by turning the gain down?

Alan

Alan, you make some interesting points.

I'm using the Baader 685 filter for galaxies and globs (PeterW's recommendation) and it works well imo. Don't see the need to go for a 640 or 610 one. Although not as remarkable as a 6nm on emission nebula, it makes galaxies much more interesting for me from my garden.

I agree that the Markarians photo is washed out. I'm still learning, but in my experience the photos either come out bit washed out grey or dark blue. I much prefer the aesthetics of the blue photos even though they may show a bit less detail. With the Samsung in pro mode, I had a play with the iso and exposure time settings. Iso can be varied from 50 to 800 and using the upper end of this range resulted in the grey photos, lower end blue. Most of the shots above were with the iso set at 50 or 100. I found the best combo was low iso and long (10s which is the max for the Samsung) exposure (I guess that's a bit obvious, but I've never adjusted these settings before). I think in future, I will use maximum exposure and maximum iso and then gradually bring the iso down until I get the look I like.

In terms of gain on the NV, for visual I generally find full gain too much (sparkling scintillated look), so I usually turn this down to around half to get close to the "normal" eyepiece look. If I start turning it down more than half, then the detail starts disappearing quite quickly, so its a bit of a balancing act depending on the object.  I tried increasing the magnification on the galaxies last night but found that much more than 60x started impacting on the detail and sharpness due to the increase in effective f-ratio.

For taking phone photos, last night I found using full gain and then adjusting the iso down low to give the best outcome, but in due course, I will compare with half gain and iso turned up a bit, to see which gives the better look and detail. Some of the photos above do have an annoying circle around 2/3rd out - I'm not sure what this is or how I can reduce/remove it. I will try my refractor next time to see if its something to do with the SCT.

Here’s a like for like grey vs blue monkeyhead. I’d be interested in people’s views on what they prefer?

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Edited by GavStar
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3 minutes ago, GavStar said:

Some of the photos above do have an annoying circle around 2/3rd out - I'm not sure what this is or how I can reduce/remove it.

That is possibly some form of vignetting. I would have thought all the other components in your optical train would have larger field stops than the NV so am not sure of the cause. Reflection of some sort?

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3 minutes ago, Stu said:

That is possibly some form of vignetting. I would have thought all the other components in your optical train would have larger field stops than the NV so am not sure of the cause. Reflection of some sort?

It does look like vignetting but really can’t understand why (I wasn’t using a reducer). Maybe some reflection somewhere exaggerated by all the tech. If it’s not there with the refractor (don’t think I noticed it before) that will help. It also didn’t seem to be there with the Ha filter and appeared with the 685...

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Great report!!!

Impressive pictures too, really great to see the dust clouds in the galaxies.

Globulars..... you've got to love them!

 

 

 

 

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More great NV observing Gavin!

Your views are similar to my 15" under dark skies generally - the Needle galaxy is very similar and using the binos on these bright ones can carve out the dust lane better, same goes for NGC 3628, the Hamburger galaxy etc. I believe this is only because you are hunting combinations to use with your NV and once you have them all figured out the views will be at least as good mine- and most likely better from truly dark skies ( I would bet on it).

M13 etc look similar if I use low power, the advantage the scope has is the easy ability to up the mag and massage the FOV with different eyepieces. Once again I believe that once your combos are nailed down you will out compete conventional scopes. The 15" excels on these clusters however and with the Binotron 27's give 3D visual images, quite a sight. I forgot to mention M82- my image brightness is the same as in your large image but with a bit more and sharper detail in the center section.

Question- does the speed factor remain the same for point source objects as extended ones? ie can you up the image scale on M13 and maintain the star's apparent brightness? I can't wait to see how this NV works from dark skies.

Great pioneering work Gavin, thanks for sharing this.

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Really enjoyable reading and great shots, Gavin! Thanks for sharing! 

It is cloudy and snowing over here, but glad to know that the sky was clear in some part of the UK and you got a chance to have a great session.

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Posted (edited)
5 hours ago, jetstream said:

Question- does the speed factor remain the same for point source objects as extended ones? ie can you up the image scale on M13 and maintain the star's apparent brightness? I can't wait to see how this NV works from dark skies.

Gerry, many thanks for the comparison comments - really useful. With point sources you can decrease the speed and hence get more image scale. So for these cluster pics I was working at about f8 (90x) when For nebulae I generally need to keep at f5 or below.

This was the first proper go I’ve had with NV on clusters so I haven’t tested how much I can push the f ratio up. I’ve heard that some in the US go up to f24 which would be a magnification of 250x on my c11. This seems a bit much but I will give it a go. 

Due to the importance of the f ratio, it seems with NV you need more scopes than eyepieces to get the range of image scale!! 😉

Edited by GavStar
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6 hours ago, GavStar said:

it seems with NV you need more scopes than eyepieces to get the range of image scale!! 😉

Thats kind of what I was thinking, but can barlows work with these things? Last night the trans was poor and my views suffered tremendously. Is NV as affected by trans as much as conventional viewing Gavin?

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1 hour ago, jetstream said:

Thats kind of what I was thinking, but can barlows work with these things? Last night the trans was poor and my views suffered tremendously. Is NV as affected by trans as much as conventional viewing Gavin?

No need for barlows, just use a smaller focal length eyepiece which do the same thing more easily. Eg for 250x on my sct I can use the 11mm delite. For even more magnification I could use say a 7mm delite but I think the f ratio would be too high.

Good transparency is useful for NV but imo the NV can help a bit to reduce the impact (in my experience in London). 

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