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The clouds that never arrived


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I've noticed that views through my dob haven't been quite as sharp in recent sessions. A quick check showed that my secondary needed collimating. As I've never done this before I was a bit nervous but a quiet Sunday afternoon gave me time to do it. I found it quite straightforward to do in the end. A star test was all that I needed to confirm that I had every aligned correctly but the forecast looked bleak. I still put the scope out to cool just in case!

Come 9:30pm, I could see Venus shining through in a clear patch of sky so out I went. I spent a long time observing Venus, trying to pick out any variations in the surface brightness. There seemed to be an elongated darker area running down one side. I'm not totally confident in this observation but it was a good challenge to try and find some detail in Venus. The only filter used was a Neodymium.

Dusk had properly settled and I moved positions so I could observe Jupiter. Lots of thin cloud overhead but nice and clear around Jupiter. First look at Jupiter at 180x immediately showed the benefits of the freshly collimated dob and what looked to be some very steady skies. All four moons stretched out with two either side of the big planet. I could see multiple belts running around the planet. More detail than I could process/describe with the views staying steady long enough for prolonged study. There were two large distinct bumps (festoons?) coming off the NEB. The Neodymium filter was again helpful. I tried magnifications up to 240x but the best views were around 180x.

A look around at the sky and everything looked clear so I continued on. I started to roam using my APM HDC 20mm and happened upon M25 in Sagittarius. Once again, I felt the benefits of collimation with the open cluster looking lovely and sharp. I enjoyed picking up the variations in the colours of the stars. I cruised over to M24 and just go lost with the great expanse of the star cloud. This is definitely an area of the sky that I'd like to explore with a nice wide field scope one day. The little open cluster, M18, looked tiny by comparison. My journey continued onward to the Omega nebula. The swan within the nebula was visible without filters but glowed through beautifully using a UHC filter. This is a real favourite of mine.

Antares was now quite well placed so I moved away from Sagittarius for now. With the time around midnight, things were getting a bit damp giving a perfect opportunity to try out my new dew heaters as well as the home made finder dew shield. Dew had brought a premature end to a few sessions recently so I was looking forward to seeing if my anti-dew setup would keep my observing longer. With Antares and it's distinctive red colour in the eyepiece, I star hopped my way to M80. The globular cluster was bright but smaller than I remembered and benefited from some magnification. Back to Antares and across to M4. The much bigger glob was more challenging and revealed lots of stars as my eye tuned into it. Lots of stars could be resolved. Whilst it's a fairly loose glob, it's character is very distinctively a glob. I've never managed M4 from my garden before so I was pleased with this. The dew on the Telrad was gone, the eyepiece and finder were both dew free too. Everything working well!

Saturn was now well risen, by current standards, so I decided to return to some planetary viewing. First look and there was the Cassini Division, clear as day. Everything sharp and well defined. Banding could be seen on the planet itself too. Magnifications went from 180x all the way up to 300x! The moons Rhea and Titan were easily seen. As time went on, I also saw Tethys and Dione as two much small points of light below the rings. There was a distinctly dark band wrapping around the planet itself. By far and way the best views of Saturn I've ever had. Such a special planet to observe. I was transfixed and returned to it several times!

A nervous look at the sky for clouds and still nothing. I got the binoculars out now and scanned around Sagittarius some more. I checked to see if M6 or M7 were high enough to be seen but no luck. The 20mm HDC was returned to the focuser and, moving away from Saturn, I arrived at another big glob, M22. Brighter than M4, I thought there were similar in size but M22 was more densely populated. Increasing the magnification again resolved lots of stars As I moved around a bright red star caught my eye. I was able to identify it as VX Sagittarii. It was really pretty shade of red and just jumped out as I passed it. The little open cluster, M21, proved a useful reference point for my observations of M20, the Trifid Nebula. An H-Beta filter can be used on the Trifid so I was pleased to finally give my H-Beta a try. Comparing the views with an OIII, I felt that I was picking up more nebulosity with the OIII and didn't see any dark lanes with either. However, these were not dark site observations so contrast was not as high as I would have liked. With the OIII still in, I finally got my first look at the Lagoon, M8, in the dob! It was a summer favourite last year and it's still a favourite now! Unfiltered, it's two bright stars embedded in a bright nebula with a small cluster next to it. Add an OIII or, my preferred filter, a UHC and the whole thing becomes set in nebulosity. This is such an impressive sight from my surburban skies (mag 19.5 or so according to ClearOutside). I'm super keen to see this under some nice dark skies!

Mars was just clearing the trees so I decided to revisit the Swan with the UHC filter and then pick up the Eagle (M16) to give it a bit more time to rise. I re-positioned everything, put the Neodymium filter in and started my observations of the red planet. My first though was that it's looking much bigger than my last observation a few weeks ago. I could see a polar ice cap and the definition to it's borders was much better than I've ever seen it. I also picked up a dark area close to the ice cap. As with Saturn, I was enjoying my best ever views of this planet. Magnification at 200x seemed the best. I lingered awhile but the reality of the alarm clock going off for work in a few hours was starting to play on my mind. So at 2:20am, I finally brought everything in. I noted the sky brightening with the first signs of dawn.

This has to be one of my best sessions to date. I wasn't expecting to get out at all but was treated to some to unforgettable planetary views as well as lovely tour of Sagittarius/Scorpius region of the sky. I felt nothing but happiness and contentment coming in afterwards. Not a cloud, literal or metaphorical, in the sky. 

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Nice write up Neil. I managed a very brief look at Jupiter, which showed great detail. Alas, clouds rolled in too quickly to end my very brief session. I did manage this image of Jupiter though that came out pretty well, taken approx 10:55pm, which shows how good the seeing was! :) 

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6 minutes ago, Knighty2112 said:

Nice write up Neil. I managed a very brief look at Jupiter, which showed great detail. Alas, clouds rolled in too quickly to end my very brief session. I did manage this image of Jupiter though that came out pretty well, taken approx 10:55pm, which shows how good the seeing was! :) 

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Great image, Gus! Those must be the festoons I was seeing. I also felt like I was seeing a thin band between the NEB and SEB which shows up on your image too. Thanks for sharing!

Edited by Littleguy80
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What a great session Neil, highly varied from planetary to deep sky! Lovely objects viewed and the 10” is obviously delivering in buckets :) Great stuff!

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33 minutes ago, Littleguy80 said:

Great image, Gus! Those must be the festoons I was seeing. I also felt like I was seeing a thin band between the NEB and SEB which shows up on your image too. Thanks for sharing!

Yes, even though the GRS was not on show, with the exceptionally good seeing last night festoons stood out very well, even to the eye alone, never mind any camera. As soon as I put my eye to the EP I could see straits away the se img was very good last night. Hoping for more nights like that to come! :) 

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23 minutes ago, Stu said:

What a great session Neil, highly varied from planetary to deep sky! Lovely objects viewed and the 10” is obviously delivering in buckets :) Great stuff!

Thanks Stu. Having spent quite a bit this year, it's really great to be out enjoying all the new gear. I'm sure the 10" is going to keep me happy for many years to come! 

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5 minutes ago, Littleguy80 said:

Thanks Stu. Having spent quite a bit this year, it's really great to be out enjoying all the new gear. I'm sure the 10" is going to keep me happy for many years to come! 

Excellent stuff. Yep, it’s a very capable scope so you can really push it to the limit to see what you can see!

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Fantastic report Neil. What a great observing session! Hopefully the telescope will hold secondary collimation for a long time. Well done on seeing M4 from your garden. I've never seen it from mine. I haven't looked at Mars this year yet but from your report and others I'm looking forward to it as I've never seen any surface detail before.

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25 minutes ago, David Levi said:

Fantastic report Neil. What a great observing session! Hopefully the telescope will hold secondary collimation for a long time. Well done on seeing M4 from your garden. I've never seen it from mine. I haven't looked at Mars this year yet but from your report and others I'm looking forward to it as I've never seen any surface detail before.

Thank you, David. Mars is well worth getting up for. Opposition isn’t far away now!

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Great report again Neil, sounds like a busy night. If the conditions are ok tomorrow night I may just have a bash at Saturn and Mars myself. Not seen Saturn yet so hoping that will be a real treat.

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12 hours ago, Ed in UK said:

Great report again Neil, sounds like a busy night. If the conditions are ok tomorrow night I may just have a bash at Saturn and Mars myself. Not seen Saturn yet so hoping that will be a real treat.

Thank you, Ed. Saturn is an such an iconic planet. When I got my 130mm scope, my only criteria was that it could show me the rings on Saturn. I got the Cassini Division with it when the seeing was good. The little moons can be tricky. Lower magnifications (50x - 75x) seemed to be the key. I think @Stu taught me that one. It’s one of the very best sights in astronomy, in my opinion at least! I'm only now becoming aquainted with Mars myself :) 

Edited by Littleguy80
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8 hours ago, Ed in UK said:

Great report again Neil, sounds like a busy night. If the conditions are ok tomorrow night I may just have a bash at Saturn and Mars myself. Not seen Saturn yet so hoping that will be a real treat.

It will Ed, it will - one of the most breathtaking views out there, even just the disc and rings.  Then when you see more detail - stunning!

Doug.

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8 hours ago, Littleguy80 said:

Thank you, Ed. Saturn is an such an iconic planet. When I got my 130mm scope, my only criteria was that it could show me the rings on Saturn. I got the Cassini Division with it when the seeing was good. The little moons can be tricky. Lower magnifications (50x - 75x) seemed to be the key. I think @Stu taught me that one. It’s one of the very best sights in astronomy, in my opinion at least! I only now becoming aquatinted with Mars myself :) 

Ageed Neil! Last year, I managed four of Saturn's moons even when it was low in the sky.  Titan was quite easy, but the others generally required AV.  Mag was x85, x113, giving  lowish exit pupils which increased the contrast for such dim objects.

Doug.

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1 hour ago, cloudsweeper said:

Ageed Neil! Last year, I managed four of Saturn's moons even when it was low in the sky.  Titan was quite easy, but the others generally required AV.  Mag was x85, x113, giving  lowish exit pupils which increased the contrast for such dim objects.

Doug.

Sunday night I was lucky enough to have 4 moons in direct vision at 180x which tells you had good the seeing was! 

I’ve been doing lots of reading on the mechanics of observing recently. One interesting thing I’ve learnt is that contrast is actually fixed. Increasing magnification dims the object and the background sky by the same amount. The main way we change contrast is go somewhere where the background sky itself is darker. What we perceive as contrast changing is just the way our eye processes the image with the changing scale/illumination (mag/exit pupil). Well that’s my understanding at the very least ;) 

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2 hours ago, Littleguy80 said:

Sunday night I was lucky enough to have 4 moons in direct vision at 180x which tells you had good the seeing was! 

I’ve been doing lots of reading on the mechanics of observing recently. One interesting thing I’ve learnt is that contrast is actually fixed. Increasing magnification dims the object and the background sky by the same amount. The main way we change contrast is go somewhere where the background sky itself is darker. What we perceive as contrast changing is just the way our eye processes the image with the changing scale/illumination (mag/exit pupil). Well that’s my understanding at the very least ;) 

Four moons in DV - good going Neil!

Contrast etc. - a most interesting topic.  I believe there is a distinction to be made between extended and point sources.  The effective brightness of extended sources is perceived at best as the br. of the sky falls, but not so much that of the object.  At higher mag (lower exit pupil), both get dimmer.  But for point sources, br. depends on aperture, so remains constant, but again contrast increases as sky br. falls.  But (as far as I understand) there is also a limit to how low the exit pupil can go (i.e. mag increases) because (apart from other things) focusing gets more critical and seeing plays more of a part in it all.

The science behind what we do and see is all part of the pleasure isn't it!?

Doug.

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29 minutes ago, cloudsweeper said:

Four moons in DV - good going Neil!

Contrast etc. - a most interesting topic.  I believe there is a distinction to be made between extended and point sources.  The effective brightness of extended sources is perceived at best as the br. of the sky falls, but not so much that of the object.  At higher mag (lower exit pupil), both get dimmer.  But for point sources, br. depends on aperture, so remains constant, but again contrast increases as sky br. falls.  But (as far as I understand) there is also a limit to how low the exit pupil can go (i.e. mag increases) because (apart from other things) focusing gets more critical and seeing plays more of a part in it all.

The science behind what we do and see is all part of the pleasure isn't it!?

Doug.

It certainly is. I've barely scratched the surface of what there is to know. I figure the more I understand about how it all works the better choices I can make when viewing the more challenging objects. I've been set a challenge to see the Pleiades Bubble. It's likely to be a long term goal but cracking that will be a big step towards seeing some amazing but very faint targets! 

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13 minutes ago, Eastman said:

Great report and write up Nell.

That 10" is doing well, nice varied objects. That must have being a nice long night observing.

Thanks Gert. It’s really proving itself to be a great scope. I always find the time passes so quickly. An hour feels like 10 mins when I’m observing. 

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