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Auroras, Cocoons, Horseheads and Deer...


Ships and Stars
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Hello all,

Typing this up while it's still fresh in my mind,  very late here. Out tonight with the 300p flextube and the trusty 15x70 Apollos on the edge of the Eastern Glens in NE Scotland. The big dob was left at home, van is in for repairs

Slow to start, nearly quit before any successes, freezing cold and gusting to 30+mph at 300m elevation, quite a shock stepping out of a warm car into the elements, but things really picked up as the night progressed. 

Around 8-9pm the moon was still ablaze, so I messed around with the binoviewers a bit, chasing the Cocoon again (determined if nothing else!). I had a possible patchy glow to the left of M39, but it was still 20.45 sqm in what should have been up to 21.75 according the LP map. The binoviewers went back in the car for the night, and I reverted to single EP viewing. Despite very clear rural skies, the Owl and M108 were extremely faint - not a good sign. I'd even cleaned the primary and secondary mirrors on the 300p today and they were absolutely spotless, along with a careful collimation on site.

Back in the car for a quick coffee and the 20mm APM - next up was Andromeda, M32 and M110 - now these were looking excellent! Conditions improving - perhaps a bit of high cloud was lurking earlier and the distant lights of Montrose were dimming slightly as the evening progressed (Montrose is a VERY bright town for its size, but then again, it's extremely dark everywhere else in the vicinity).

But wait, what's that glow on the northern horizon? Distant LP? Nope - aurora! I spent some time watching it pulse and ebb faintly, then a big spike of light went up like a searchlight. Then another, with a low hanging curtain of light slowly drifting NNW. This went on for a bit until I resumed my obsession with the IC 5146, the Cocoon Nebula. I've really struggled with this one, until a trip over a month ago to really dark skies where I was sure I saw it with filtered 15x70s (Astronomik UHC on one side and Nebustar II on the other). But then that sensation of doubt began slowly creeping in the past few weeks. Did I see M39 and mistake it for the Cocoon? If I can't see it clearly in a scope, then I've no chance with binoculars, right?

So I went for the 300p with 17.5mm Morpheus/Hb filter and worked over the area. I chased the dark lane to the left of M39 and think I had some mottled nebulosity towards the end, but it was nothing to shout about - very faint. Going for a larger exit pupil, I swapped to a budget Revelation 25mm plossl... and success! A nice sub-circular undulating patch of nebulosity. Experimenting with a 32mm plossl, it became even brighter, so this tells me my eyes were doing well with an exit pupil of 6.51mm! Good news there.

There was only one thing left to do now - get the 15x70s back out and see if I could repeat my earlier claim of having seen it. Hmmm.

Up past Deneb and the NAN with the bins, there was M39 with the two bright stars above (Azelfage mag 4.65 and n2 Cyg mag 4.4). Clear as day to the left of M39 was a dark lane which had a short spur running south. The dark lane narrowed and clearly ran through a patch of stars (9-10-ish mag apparently according to Stellarium) then the dark lane took a slight curve and became fainter until voila, a clear circular patch of nebulosity with three mag 7 stars immediately to the left. I couldn't believe it! It was clearer though the binoculars that it was in the scope! No doubt about it, I dare say the Cocoon was easy to spot with the filtered binoculars and the dark lane stood out sharply. I replaced the UHC on one side with the Hb and while it was still easy to find again, it lacked the punch. So I'm not totally convinced an Hb filter is the way to go for the Cocoon, I may try the Morpheus with the Nebustar next time, but I was satisfied at last with the Cocoon. Now I know where it's at for sure, I'll have a bash with the 20" soon. 

Then it was Orion and... the Horsehead. After admiring M42/43 for a little bit, I got down to business with the 17.5/Hb combo. Mmmm, not much below Alnitak and no decent sign of the Flame Nebula, so I went off to view some other areas for awhile, then swapped the 25mm plossl in.

The Horsehead was visible with averted vision and in and out direct vision as a dark notch, but void of detail - still, I'll take it. Swapping again to the 32mm, it was that little bit more prominent with the larger exit pupil. Good stuff! The 300p doesn't compare to the 20" on the really faint stuff like the HH, but it holds its own and offers a lot of aperture for the money. A truly transportable dob capable of some good DSO results. 

The Flame Nebula was nicely visible as well this time, getting darker and darker as the moon went down - hit 21.03 sqm.

The Rosette was next, 20mm APM and OIII - it didn't pop like I thought it would, but the nebulosity was there, extending past the FOV. So once more, I grabbed the UHC/Nebustar bins and wow - what a nice view - the entire nebula was clearly visible, situated nicely within in the FOV, an excellent sight and another binocular surprise.

I will wind this report up, it's past 3am now. I packed everything up and ended with a quick trip through Auriga plus a few other areas, M108 and the Owl looking great at last, and one last look at the Cocoon and the Veil with the bins, excellent! A few other sights, but fatigue prevents me from rattling on any more ;) 

PS  a deer ran out on the way back, then as I moved forward, two more so I did a sudden near-panic stop with the dob base shifting around in the back seat. Oooof, close call. Taking off carefully again, a fourth deer jumped out at the last second. I was only doing 30-35mph instead of my normal 50+ through back roads, good thing, or I would have made contact for sure. Steady on driving back late at night! 👍  

Thanks for reading. Until next time...clear skies all

 

 

 

 

Edited by Ships and Stars
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3 hours ago, Kyle Allen said:

Nice report. Thanks for posting. 

 

3 hours ago, estwing said:

What a belter of a night and a great report!....well done.

 

1 hour ago, John said:

I enjoyed reading that - thanks for posting it :smiley:

 

Thanks all! @John - your advice on exit pupils last year or two are proving particularly valuable as of late. My fully adapted pupil is somewhere around 6mm, maybe a tick larger I'm hoping, so I need to really approach that for the really faint stuff - doesn't matter if it's an expensive EP or not, exit pupil is critical it seems.

I very nearly packed up early on when the moon was still up - glad I didn't. The wind settled down and the cloud that was expected never materialised so it worked well.

I've been getting readings much lower with the SQM than the LP map suggests. I know conditions change and readings go up and down, but the readings seem a lot brighter than I was expecting. 

I'm thinking about another late jaunt this evening if my energy holds up - I want to test a few other things now.

I think I was struggling with the 300p because of exit pupil, eyepieces and lack of 2" filters. A plossl in some cases gives too narrow a FOV to provide contrast with the surrounding sky (I run into this with the 10mm BCO vs the 9mm APM) and my wider EPs in the 1.25" range are too high mag/too small exit pupil, i.e. the Morpheus. I wish Baader made those in the 2" range. The 15x70s bins aren't brighter, but they offer contrast on low brightness extended objects by showing tons of the surrounding sky and I can locate new targets with more confidence. 

I'll perhaps consider taking the plunge on some 2" Hb and Nebustar filters and a wide field 24-28mm EP. Ouch! £££

On second thought - I might dust off my 2" 28mm SW LER eyepiece and the 2" 31mm Baader and carefully tape a 1.25" filter on top to test tonight 🤣 Or will that just be the same FOV as a 28mm 1.25" ep?

Hoping for another interesting night tonight - the scope is already in the car, that will spur me on.

Edited by Ships and Stars
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5 minutes ago, domstar said:

A great read. It makes me feel a bit guilty for staying in the warm last night when the sky was clear. M 108 really is a nightmare for me. I find it much more challenging than I think it should be.

M108 is a bit tricky at times even under fairly dark skies as last night confirmed - it often simply appears as a faint sliver that is slightly bloated in the centre unless conditions are right.  On a transparent night in the 20" it looks impressive, but other times it's just a small grey blip. Galaxies like aperture, dark transparent skies and they definitely dislike filters! I will use an OIII to enhance the Owl, but can fit M108 and the Owl into the FOV with the 20mm APM and no filter quite nicely. 

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Brilliant, a quite full on report. Great that you got a chance to get out Robert and with the good conditions currently along the east side. Interesting description for elements of aurora early on and for approaching observing the Cocoon. A large exit pupil and if combined with comfortable eye relief, applied to filtered observing is a revelation for revealing clarity within faint diffuse nebulae; within optimum conditions. The SQM is such a useful and informative tool for gaining an accurate account for registering sky brightness at a specific time and place. First account this season I think for the Horsehead and Flame, well I'm Iooking forward to that to. The Horse Head can be so fickle, requiring experimentation when it comes to determine exit pupil and best most 'contrasting' view. Great conditions here to in Newcastle, but with the current lockdown circumstance was reluctant to go anywhere, beyond the backyard again. 2" HB filter will be very useful.

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Thanks Iain @scarp15 I was very happy (and relieved) to have seen the Cocoon again with the binoculars, thought I was being overly optimistic on my trip to Glenshee last new moon when I spotted it the first time. 

I'm still pretty amazed with the bins on that and the Rosette! Maybe I can pick up a hint of Barnard's Loop with them under ideal conditions? Worth a shot I suppose. I'll ponder a 2" Nebustar or a 2" Hb, can't afford both at the moment, tempted to go for the Nebustar and then an Hb when one comes up secondhand (rare though!). It's a hard call, the Nebustar works so well. 

Just happy to get some observing in, hoping the NE doesn't go to full lockdown soon, I can't keep up with the restrictions anymore it's changed so much! 

Hope you get a break soon, I won't have the big dob out again until mid December most likely.

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1 hour ago, Ships and Stars said:

Thanks Iain @scarp15 I was very happy (and relieved) to have seen the Cocoon again with the binoculars, thought I was being overly optimistic on my trip to Glenshee last new moon when I spotted it the first time. 

I'm still pretty amazed with the bins on that and the Rosette! Maybe I can pick up a hint of Barnard's Loop with them under ideal conditions? Worth a shot I suppose. I'll ponder a 2" Nebustar or a 2" Hb, can't afford both at the moment, tempted to go for the Nebustar and then an Hb when one comes up secondhand (rare though!). It's a hard call, the Nebustar works so well. 

Just happy to get some observing in, hoping the NE doesn't go to full lockdown soon, I can't keep up with the restrictions anymore it's changed so much! 

Hope you get a break soon, I won't have the big dob out again until mid December most likely.

Yes definitely worth a shot, I think filtered you will be successful. A wide field binocular view and with relaxed two eye observing will present, if you were somewhere like at GlenShee and within good transparency some success. I like your detailed account for tackling the Cocoon, will inspire me to explore it again next year. Barnard's Loop is of course challenging to but not unreasonable applying the same approach; practice, patience and experimenting. Large exit pupil, wide field of view and H-beta filter. 

Depending on the level of restrictions imposed which yes can be confusing, will be hoping for getting out in December. Haven't even been able to visit my aging parents since March, at least by this time next year, circumstances should be more normal perhaps.

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@scarp15 sorry to hear that about visiting your parents! That's a long time indeed. I haven't kept up with restrictions in England, so hope I haven't wound anyone up with observing reports if people are stuck at home. I've had a lot of bad weather here lately, so trying to make up for it while I can! I was wondering why there weren't many new observing reports...assumed it was weather related, certainly has been here.

I didn't realise Hb filter was the way to go on Barnard's Loop? Thank you! Saved me some frustration there! I had no clue on filters for that to be honest. 

Hopefully we will all have some luck here soon.

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2 hours ago, Ships and Stars said:

@scarp15 sorry to hear that about visiting your parents! That's a long time indeed. I haven't kept up with restrictions in England, so hope I haven't wound anyone up with observing reports if people are stuck at home. I've had a lot of bad weather here lately, so trying to make up for it while I can! I was wondering why there weren't many new observing reports...assumed it was weather related, certainly has been here.

I didn't realise Hb filter was the way to go on Barnard's Loop? Thank you! Saved me some frustration there! I had no clue on filters for that to be honest. 

Hopefully we will all have some luck here soon.

Thanks Robert, they live in Lancashire, sisters been keeping an eye on them. Definitely welcome all of your reports, circumstances aren't joined up across the nations, so can be a bit confusing. England's current lockdown before going back to a tier system finishes on the second. Weather related is still a typical factor. Yes HB filter - 2" for Barnard's Loop, even so it's very subtle and of course check up on Mel Bartels sketches.

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Great report, shows that aperture isn’t everything for these nebulae!. Many of those nebulae you’re after are of the galactic hydrogen variety so a hydrogen beta filter would be the way to go.
 

Trust the SQM, those online maps look nice but have not been locally calibrated. You’ll find nights vary a bit, practice checking the Bortle descriptions to narrow things down, seeing you’re lucky to have dark skies not too far away.

Peter

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4 hours ago, PeterW said:

Great report, shows that aperture isn’t everything for these nebulae!. Many of those nebulae you’re after are of the galactic hydrogen variety so a hydrogen beta filter would be the way to go.
 

Trust the SQM, those online maps look nice but have not been locally calibrated. You’ll find nights vary a bit, practice checking the Bortle descriptions to narrow things down, seeing you’re lucky to have dark skies not too far away.

Peter

Thanks Peter! it feels like the Hb filter can be a bit too restrictive for the 15x70s aperture but it is always worth testing on different nights. It does of course work better in the 12" dob as long as I have a decent sized exit pupil with an EP in the 25-32mm range. In the f4 20" dob, the Hb really works and can hoover up the dark stuff nicely.

The Nebustar lets though the Hb and OIII wavelengths fully from what I understand (I'm no real expert on filters!) and it really seems to shine on the 15x70s with a quality UHC on the other side. I'm tempted to buy another 1.25" Nebustar someday, but I also need a 2" Hb and a 2" Nebustar...

Indeed, the LP map is a good rough guide, but since I've had the SQM-L meter, I've noticed a wide range of readings from the same spots on different clear nights with no moon. I was surprised it only went up to 21.03 at this spot, should have been much darker, but perhaps the aurora was bumping things up a bit? The town of Montrose in the distance does pump out a lot of light, there is some heavy industry on the edge of town that is always lit up to the max. I think the mass rollout of cheap, ultra-bright LED lights and the relentless march of 'progress' have meant that readings from even 5 years ago may be permanently brighter now unfortunately. The only place I have been able to approach the readings indicated by the LP map are deep in the Cairngorms, miles away from the nearest homes and roads (a consistent 21.85 one night!). 

I'm finding anything over 21.00 with good transparency can yield great results for visual. Anything over 21.50 with excellent transparency is a sight to behold.

The 15x70s with filters have really impressed me lately for their size and aperture, can't believe the views with those. As a result, I finally brought my 20/40x100mm Quantum 5.1s (the older ones) up to speed by making filter threads for both the 20x and 40x eyepiece sets as no other 1.25" EPs will come to focus without machining off the bases a considerable amount. Yesterday, I also ordered a nice fork mount from TS Optics to mount it properly and have a way to lock it steadily when viewing objects at higher altitudes. I can't wait until the next new moon in December as I have yet to use these under dark skies since I bought them in March! 

Hoping to report back some successes next new moon, weather willing. 👍

Edited by Ships and Stars
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H-beta filter(s) ought to work Robert with your 15x70's, which I expect would be around 4.5mm exit pupil. Admittedly a small, wide field refractor in which you can experiment with exit pupil can yield outcomes when a H-beta is applied. At least I have used a 76mm f6.3 refractor to view the California, previously had a 70mm refractor and that would have worked to. Concerning the northern section of Barnard's Loop, I have used my 85mm refractor and applied a 5.8mm exit pupil to cruise along the curvature someway south. This was at a dark sky area along the England Scotland border.  

As Peter mentions and as you know, the online sky brightness readings are to used as a very broad reference. Areas I tend to go to are meant to be up to 21.85, realistically a very good night, perhaps by early morning is usually measured as 21.3-4, the exception being near the border at Carter Bar, which I anticipate will reach 21.6 - 21.7 mag. 

You mentioned in your report concerning deer and abruptly coming into view across a road. A good point that probably needs to be more widely shared for anyone venturing into backcountry on dark sky trips. There is a road section close approaching my most often used site, adjacent to forestry, a particular spot on the road is a frequently used trail for roe deer and I take extra care, having encountered quite few passing by.   

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Our club dark site is a little over 21, but as  you say, transparency is key. >21.5 in the U.K. will be pretty rare. LED depending on colour warmth can be erroneously measured with satellites and SQM. It’s sad the people have started over using LED, an opportunity missed to make things cheaper and better for everyone L

When you have binoculars your filter collection can start to breed like rabbits! I am enjoying my tripod mounted angled 70mm and waiting to see what dark skies will let it deliver with them. Fully stable two eyed views make the faint stars pop into view, aperture just changes image scale for a constant exit pupil. There seems a recognition that binoculars can hold their own against “the big stuff” (dobs), picking up some pretty dim nebulae.

Smaller kit certainly is easier to fit in a flat, but the costs of two eyed views certainly do not scale linearly!

 

PEter

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“I've been getting readings much lower with the SQM than the LP map suggests. I know conditions change and readings go up and down, but the readings seem a lot brighter than I was expecting.”

I have several hundred readings now from two sites with my sqm-l, and the best readings from each match quite closely to the lightpollutionmap.info modeled values.

I have regressed a model from each site and find that sun altitude above -18 degs below, same sun alt squared, moon alt, moon phase, are all significant factors in estimating darkness to expect. But I like you have been disappointedly flummoxed that lately my readings have been rather brighter than expectedgtomy dark site, 21.8. On a hunch I added “angular proximity to MW” as a factor to my model, and the variation was explained! Essentially in the summer months you’re pointing the meter at zenith to the MW and it makes a big difference!

My best formula for my 21.8 location based on data so far is

SQ = 21.949 + 0.2436 x sunalt - 0.0697 x sunalt^2 - 1.9336 x moonphase - 0.0330 x moonalt + 0.005657 x MW_prox_to_zenith [alts and MW prox in degrees and phase in space 0-1.000. And where sunalt is no. degs above -18 and zero below, similarly moonalt is actual moonalt but zero below -10 degs]
 

 

Edited by Captain Magenta
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10 hours ago, Captain Magenta said:

SQ = 21.949 + 0.2436 x sunalt - 0.0697 x sunalt^2 - 1.9336 x moonphase - 0.0330 x moonalt + 0.005657 x MW_prox_to_zenith [alts and MW prox in degrees and phase in space 0-1.000. And where sunalt is no. degs above -18 and zero below, similarly moonalt is actual moonalt but zero below -10 degs]

Fascinating stuff Magnus! I’ve been thinking of building a diy SQ meter and if i do i’d really like to try out your equation to see if it predicts my readings. One question though, what about transparency? Doesn’t moisture/dust in the air greatly affect SQ by bouncing back local light pollution?

Mark

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1 hour ago, markse68 said:

Fascinating stuff Magnus! I’ve been thinking of building a diy SQ meter and if i do i’d really like to try out your equation to see if it predicts my readings. One question though, what about transparency? Doesn’t moisture/dust in the air greatly affect SQ by bouncing back local light pollution?

Mark

Isn't that where the value of this will formula shines through? 

The formula tells you what the brightness should be on a given night.  And the difference between that and an actual reading is a measure of transparency?

Edited by globular
typo
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6 minutes ago, globular said:

It's that where the value of this will formula shines through? 

The formula tells you what the brightness should be on a given night.  And the difference between that and an actual reading is a measure of transparency?

I was just thinking that Glob- I guess that’s what it would tell you yes :)

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The formula calibrated by regression from actual readings will naturally already have 'average' transparency built in... so it may need adjustment to allow for this.... or accept that matching the formula will give you average transparency and bettering it will be above average.

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1 hour ago, markse68 said:

Fascinating stuff Magnus! I’ve been thinking of building a diy SQ meter and if i do i’d really like to try out your equation to see if it predicts my readings. One question though, what about transparency? Doesn’t moisture/dust in the air greatly affect SQ by bouncing back local light pollution?

Mark

I can calculate the variables in the equation, sun alt, moon alt, moon phase, proximity to MW etc, but things like transparency airglow and light cloud veil are difficult to estimateor see, so they will contribute to the final errors in the regression.

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