March 19, 2015 – The Baader Moon and Skyglow Filter and the Crabby Astronomer

The same day as the Levenhuk/Baader solar filter arrived, another filter arrived, too:  The Baader Moon and Skyglow Filter.  Suh-weet!  So, between the sun and the night sky, it was really a very full and enjoyable day and night of observing.

The M&SG is, in one sense, a weaker version of the Orion Ultrablock filter I got a few weeks ago.  With my insane Manhattan light pollution, why would I ever want something weaker?  Well, there’s a few reasons, and to understand that, we have to review again and understand what each of the filters does.  I already discussed the general landscape of filters in my post about the Ultrablock filter last month.

All filters block certain amounts and wavelengths of light, with the result that the overall view is dimmer to a greater or lesser extent.  The Ultrablock, a narrowband LPR filter, definitely does remove a significant amount of light from your view, and has an overall dimming effect.  Although the Orion Nebula itself really pops into view, the stars themselves are dimmed slightly.  The Ultrablock works by making the background sky darker while it is also making the object darker as well – but just not as much.  This is particularly noticeable on the dimmest of the four stars in the Trapezium.  However, because it is acting more on the background than the object, overall contrast is increased, making the detail really come out.

On the other hand, the M&SG is a broadband LPR filter, and is not supposed to have that overall dimming effect at all.  It is supposed to pass as much light as possible, while dimming just the two main light pollution bands from streetlights – the sodium and mercury vapor bands.  All the other wavelengths are supposed to pass through freely, and thus the reason it’s called broadband.  As opposed to a standard broadband LPR filter, the M&SG is also supposed to reduce the glow from the moon as well, as the moon definitely has the tendency to drown out faint objects when it’s up.

Another of the special things about the M&SG as opposed to other broadband LPR filters is that it is supposed to be able to increase the contrast on the planets and the moon.  I haven’t really heard of that ability with other broadband LPRs; and more to the point, the Baader is supposed to be particularly adept at doing this.  Not only other people’s reviews on Cloudy Nights, but also the claims at the various websites themselves is that the Baader is supposed to really make the features on Jupiter pop, especially the GRS.  And I’m all about popping those solar system objects.

So, time to get out under the sky and do a little compare and contrast.

The M&SG arrived the same day as the solar filter arrived, so I left the telescope out after having observed the sun that afternoon.  Since it was definitely spring-like temperatures – well, almost spring-like, anyway – the scope was plenty cooled down for the evening’s observing that night.  Although the seeing wasn’t THAT great, it seemed like it was extra clear out for some reason.  The stars were really shining a bit more brightly that night – great transparency.

I had bought the M&SG partly because people said it really improved your ability to see detail on Jupiter and the moon, but also because it’s in my blood not to be able to pass up a really good deal on something I really want to try out.  I got it for literally half price at an eBay auction.  Although the earth’s moon wasn’t out, the Jupiter calculators were showing that there would be both a shadow transit of Io and a GRS transit at the same time, so I definitely wanted to get out and see both of those.

I first used my 10mm Sirius Plossl to get 154x.  My 8mm TeleVue Plossl was just a touch too much power at 193x, so I backed off back to the 10mm. Things up Jupiter’s way were looking decent until I screwed on the M&SG.  Well, those people who said it improved the views of Jupiter weren’t just whistling Dixie.

The GRS just popped right in view.  I mean, I had seen the GRS before a couple of times, but just barely.  I had seen it more as an absence than as a presence – a gap in the equatorial band where I knew the GRS had to be, and just a little something there seen with averted vision as the seeing steadied.  This time, I actually saw a nice big oval there for the first time.  It was unmistakably there – no averted vision or anything.   The equatorial bands, always easy to see, looked more defined.  And Io’s shadow was a very well-defined inky black dot.  Really gorgeous stuff all around.

Jupiter was fun and all, but I wanted to see what the filter could do against light pollution – the world’s worst light pollution.  Apparently, not much.  I put the 32mm Plossl in and tried it on the Double Cluster, that showstopping showpiece of the sky.  I couldn’t see any difference.  It’s a great object, er, objects, so there’s a lot going on there.  But I suppose that the LP here in The Big Apple is so overpowering that a broadband filter really can’t have that much of an effect.  After all, broadband LPR filters are always written up as being for use in “mild” LP.  Well, what I got sure ain’t mild, that’s for sure.  And so, I didn’t really see any difference with the filter as opposed to without on any of the open clusters I tried.

This week, I took a gander at M3 and M53, a couple of spring season globular clusters rising in the east and reaching about 45 degrees above the horizon just after 11pm.  M3 is relatively bright at magnitude 6.3, while M53 is fairly dim – at least in Manhattan – at 7.7.  I waited until after 11 so I could get the best views, both so they could be relatively high in the sky, and so that the light pollution would start to go away, as this is when people start going to sleep and turning out their lights for the night.

Neither object was overly impressive, but they weren’t too hard to find – the goto was particularly accurate last night.  Both looked like faint out-of-focus blobs, even when they were in focus, which I made sure they were; obviously, M3 was a good bit brighter than M53.  In fact, M53, although definitely there, was only really visible when the telescope was slewing towards it, or, once there, through averted vision.

I tried the M&SG on M3, the brighter one, first.  I first used the 15mm Paradigm, 103x, with and without.  Then, because a wise astronomer has said that one of the best ways to deal with LP is to spread it out and make it dimmer by magnifying it, and because one of the things you’re supposed to do with globs anyway is to magnify them to see if you can resolve the stars, I went for the 8mm TeleVue, 193x, with and without.  Regardless of the magnification, I could see no difference.  I tried it on the dimmer M53, hoping that the filter would make it pop out a little more from the light-polluted background.  Still nuthin’.

Maybe the M&SG works better on DSOs out in the country where the LP is much less, but it sure ain’t working on them in the City.  Still, for it’s work on Jupiter alone, it’s a keeper.  Next week, I’ll try it out on the moon.

After the experimenting with the new filter, I wanted to continue my testing and see what the “old” filter could do.  I decided to use the Ultrablock to try for my latest nemesis, the Crab Nebula (M1) to see if I could see it for the first time. I’ve always wanted to see it – after all, it is the first one on Messier’s list.  And it’s a famous one even beyond the list.  The Crab is the remnants of a supernova that Chinese astronomers observed in 1054.  It’s listed as being magnitude 8.4, and it’s riding very high in the sky just after dark, thus avoiding the dimming effects of the atmosphere as much as possible, so it should be visible even from Manhattan.  But is it?

The 8.4 is what’s called integrated magnitude; that means they collected all the light from the object and acted as if they shrunk the object down to the pinpoint size of a star.  An object gets dimmer as it gets larger, because you spread that same amount of light out over a larger area.  Sure, I could see 8th magnitude stars no problem, but the surface brightness of an object like the Crab is much less than the quoted number because of this spreading effect.  In the Crab’s case, the light is being spread out from a point source to an object that’s 6 minutes long by 4 minutes wide.  Stellarium lists this surface brightness as 12.1.  Yikes!

It is precisely for this reason that virtually every galaxy on the Messier list is invisible to me, or, as I like to think about it, dead to me.  I’ve never much cared for galaxies, because I’ve always tried to observe them from light polluted conditions, whether here in Manhattan, or back when I was a kid in the suburbs.  One dim fuzzy patch looks very much like another, especially when you can’t see any detail anyway.  Maybe if I ever got out to a really dark site, my opinion would change.

The goto alignment seemed to be working pretty well that night, so off I went to M1.  The scope slewed over and stopped and a star was in the field of view.  With the Ultrablock, it sure seemed a bit fuzzy.  Could this be the Crab?  I proceeded to my full nuclear bunker setup – eyepatch, hood over the head to block out all stray light, and sit and wait and stare for 5 minutes.  10.  After 15 minutes, I wasn’t seeing any more than I had when I started.  I moved the scope around to see if I was actually on it, or if I was in the right or wrong neighborhood, or what.  I couldn’t tell.  But other stars started seeming fuzzy too.

I concluded that one of the unfortunate side effects of the Ultrablock is to make stars look fuzzy if you stared at them long enough.  Unfortunately, that means that I’ll have to retract my earlier sighting of M43.  I went back to M42 to confirm this, and yup, that little star across the way where I thought I had seen M43 was just as fuzzy – or not – as the other stars I had been observing around M1.  Oh well.

Perhaps I can snare the Crab on some other night of better seeing – or if there’s some kind of blackout.  Oh, please, let there be a blackout.

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