Thursday, 21 February 2013

Clouds, polar bears and greetings

Few nights ago I happened to stumble upon the re-opened website of our beloved old geezer Stephen R. Waldee. Steve asked in this January blog entry "... but what's happened to the regular entries by such interesting writers as David Knisely, Steve Coe, Steve Gottlieb, Mark Wagner, my friend Jaakko and several of his colleagues in the frigid north above the arctic circle?"

Finland: Sibelius, Sauna, Sisu and polar bears... wait what?
Courtesy of San Jose Zoo.
I do not know about the rest of the guys, but the winter here in Finland (which is mostly well BELOW the arctic circle) has been the cloudiest in recorded history(?). For example the town of Jyväskylä, in Central Finland has seen only 18 hours of sunshine during the past 2.5 months! So no matter what you try, there's no beating the clouds. The temperatures, observing conditions in general and cloudy days are something most people living in Central/Southern Europe / US cannot even fathom. The thought of planning an observing session for tonight/tomorrow, is something we're not familiar with. With the weather patterns in here, clouds will always sneak up on you. Not to mention the general changes in weather even I've witnessed over the past few decades: more clouds, warmer temperatures and simply crappy winters in general. So if you want to start astronomy, do it somewhere else than in Finland!

NGC 55
Despite the cold spell on the homepage front, many things have been going on. I still have a huge pile of sketches to be scanned and processed from my trip to the US as well as Tenerife. Here's an example: NGC 55 sketched with a 4.7 inch scope @ 90x (45') from Boca Tauce, Tenerife, Spain (2034 meters / 6673 feet) on 23rd of November 2011. The description reads: "A gorgeous sight. Huge, WNW-ESE elongated galaxy with a mottled appearance. NW part of the galaxy contains a bright, elongated nucleus with somewhat mottled appearance. Two brightenings visible within the halo. Larger and brighter knot appears as slightly NW-SE elongated. The smaller and fainter knot appears as a nearly stellar, roundish spot in the E side of the galaxy's halo with a faint 14th magnitude star just W of it. A darker void seems to separate these two possible HII-regions from each other. Several 10-14th magnitude stars in vicinity / within the halo. Size 20' x 4'. With low power the galaxy is visible in the same field of view with pointy rock formations of Las Cañadas caldera."

Between this post and the latest entry from less than year ago a lot has been going on behind the scenes. I've managed to contribute several sketches to the Las Vegas Astronomy Society's (LVAS) "Observer's Challenge". Four of my "Deep Sky"-columns have been published:
Tähdet & Avaruus 8/2012
  • Hunting the invisible: Cygnus X-1 (Tähdet & Avaruus 4/2012)
  • The Prince of Darkness - E. E. Barnard (Tähdet & Avaruus 6/2012)
  • Colors, details... oh my - Going against the Hubble Space Telescope (Tähdet & Avaruus 8/2012)
  • Fifteen years of astronomy - The fondest memories (Tähdet & Avaruus 2/2013)

The "night sky" in Tapanila, Helsinki
So although it might seem bad on the outside, I'm still alive and breathing. This past year has brought many life changing things to my life. The one with the biggest impact was moving from the outskirts of Vantaa to rural Helsinki. The drop in SQM-L readings, limiting magnitude and huge increase in light pollution has had a really negative impact on my hobby. Not to mention living on the 3rd floor. Trust me, when the SQM-L readings drop below 18, that's when everything that's fun and worthy in observing - dies. When the snow melts away in a month or so, I'll probably try to do some observing before the summer break. One thing I've changed in my sketching is the speed. I've started to spend even more time on a single object than usual and it is starting to pay off. Simply put: more vague details than ever! And Steve, I'm sure you still have my email address. If you don't, you can see it if you're reading this. Use it buddy!

Saturday, 28 April 2012

Cosmic Challenge by Philip S. Harrington - A review

Cosmic Challenge - The Ultimate Observing List for Amateurs by Philip S. Harrington
Cambridge University Press (November 30, 2010)
ISBN: 9780521899369
466 (true) pages

Rating: 8/10 - Recommended









The ultimate observing list for amateurs. With such a name for a book you're entitled to some serious challenges from the night sky. I have to admit, I wasn't sure about getting this book. The main reason was, that I don't like digital sketches and I knew Philip's are digitally made. For me, such sketches easily spoil any book, article or anything they're associated with. Using, say Adobe Photoshop might let you do all the work with a computer but even a simple diffuse, nebulous glow is something that a computer cannot do properly without making it look otherworldly. And digital sketches hardly represent the true eyepiece view - this is the main reason why I dislike them.

So how are the sketches in the book? Well, surprisingly good. There are some bad apples to my eye in the bunch such as: M57 and NGC 7331 to name a few. The biggest problem by far in the book is that the most of the sketches are so low contrast that you actually have to us averted vision to spot them! I understand this is to represent the difficulty of the objects and how they even can look at the eyepiece but contrast up man! This issue was already discussed in CloudyNights.com but I was surprised at how obvious it was. Also, the accuracy of star placement in some of sketches is staggering to a point I wonder if they've been actually done to a printed starfields? I'm not saying such accuracy is impossible to achieve - it would just literally take hours. Most of the drawings have very, very high accuracy but some have some misplacement here and there but this is rare. So I suppose the original sketches are handmade.

What of the actual challenges? You can, of course, have many thoughts about them. I love the fact that there are so many of them and more importantly for all apertures! What a great idea to have some naked eye challenges for a start! I would have liked to see sketches of them too which sadly are missing.

I personally would have changed several objects to different telescope categories but this isn't MY book is it. I'm glad there are some real challenges (although a bit too obvious ones) for monster telescopes (15 inch aperture and larger) such as Einstein's Cross, Hickson 50, Seyfert's Sextet and so on. From my point of view, some of the monster telescope challenges should be in large telescope challenges instead (10- to 14 inch telescope). Such objects are Leo I, IC 1613, (brightest of) M31 globulars, Terzan 7, WLM, Simeis 147 are most certainly small telescope challenges (although being difficult with larger ones as well). For example the author speaks of how difficult it is to observe the entire Simeis 147 at once in the narrow fields of view of large aperture telescopes. Could there be a better place for a high quality, wide field refractor than this? No! Especially considering that there are many observations of the object seen only with apertures around 4 inches! Some other that did hit the eye were galaxies beyond M44 (if you remember, Steve Waldee has seen all of these listed in the book with his 10 inch telescope!), Copeland's Septet, PK 164+31.1 (both visible with 8 inch aperture) and several other galaxies and groups should at least be downgraded to the "large telescope challenges" for sure. But most of the "bad" things in the book can be discarded as matter of opinion and personal taste. Other little things I noted (desperately grasped on) include:
  • If you see M13 (non stellar, 5.7 magnitude object) with the naked eye - your naked-eye limiting magnitude can't be 5.5 but is more likely 5.9 at least.
  • Seeing M33 with the naked eye doesn't really need "absolutely, perfectly pristine skies". It is actually quite easy to see even from Finland which isn't even remotely absolutely, perfectly pristine anything.
  • Chart 5.19 IC 10 (page 264) says "Sculptor". It probably should read "Cassiopeia".
If you want something simple and short, here it is: the book is simple (in a good way), easy to navigate and the charts are most excellent. It is well written and while some might argue the text portions are a bit on the short side, I don't find this a problem but actually a bit of a relief (after reading O'Meara). Despite my - at first - biased view of it, the book is far from bad. It is quite excellent and I would recommend it to... well every amateur astronomer out there. And good to see my friends and colleges Timo and Steve mentioned in the book as well. I'm looking forward to volume 2.

8/10 for every living soul - Recommended

Friday, 13 April 2012

5 curious and nearly unknown nebulae for photographers

Have you already taken a photo of every Messier object in the sky - twice?
Nothing in MegaStar that you haven't already photographed?
Looking for something different? Here's your chance!

Image courtesy of DSS (Digitized Sky Survey)
LBN 437(a) / V0375 Lac (Markarian 914)

Coordinates: 22 34 05 +40 42 36 (Lacerta)

Eastern part of the LBN 437 complex - designated here as LBN 437a. Small 2.5' nebula concentrated around the variable star V0375 Lac - sometimes credited as a galaxy Markarian 914. The size of the whole eastern complex is roughly 20'.










Image courtesy of DSS (Digitized Sky Survey)
LBN 437(b)

Coordinates: 22 30 13 +40 28 13 (Lacerta)

Western part of the LBN 437 - credited here as LBC 437b. Total size is roughly 30' x 12' and forms a shape of a dragon, monkey or a lizard. You decide. Bright star near the "head" of the dragon is 8th magnitude HD 213472.













Image courtesy of DSS (Digitized Sky Survey)
GSC 790-523 nebula

Coordinates: 07 43 15 +14 48 05 (Gemini)

This anonymous nebula is surrounding 13th magnitude star and is 3' in size with fainter filaments continuing to south. Bright 9th magnitude star HD 62120 is just west of the nebula.














Image courtesy of DSS (Digitized Sky Survey)
TYC 3651-1162-1 nebula

Coordinates: 23 57 11 +50 41 55 (Cassiopeia)

Small (12' x 10') anonymous detail of a huge nebula complex. Brightest part is located just south of TYC 3651-1162-1. Forms a shape similar to that of an ear or Crescent nebula (NGC 6888).













Image courtesy of DSS (Digitized Sky Survey)
HD 41397 nebula

Coordinates: 06 06 59 +54 54 51.9 (Auriga)

Anonymous nebula complex with several individual patches visible in a 30' area. The brightest individual puff of nebulosity is located W of magnitude 10.6 star TYC 3755-802-1 with a size of ~4'.








Tuesday, 10 April 2012

Naked eye test - M44

I did a little test on the visibility of Messier 44 in Cancer without optical aid. As it is impossible to make identical observations of the same object on two different nights, the results are directional at best. More data will be added later on but it would seem that in order to see the cluster with the naked eye, the limiting magnitude in the region should be close to 5.0. This is slightly less than my previous estimate of 5.2 (Deep Sky Naked Eye Limiting Magnitude 2005 / Saloranta). Next in line would obviously be the visibility of M35 (unfortunately "out of season") and M13.

Based on personal experience, in order to see M44 with the naked eye from suburban location:
  • Delta Cnc (mag 3.9) needs to be visible with direct vision.
  • Gamma Cnc (mag 4.7) should be visible at least 50% of the time with averted vision.
  • Theta (5.4) and Eta Cnc (mag 5.3) will probably be invisible.

M44
Castor, Pollux, Mars and M44 barely visible in the pinkish hue of light pollution

How were the observations made?

  1. The same observing spot was used on all occasions.
  2. M44 at an altitude of 40 - 50°.
  3. The weather was very similar on all occasions.
  4. Dark adaptation (night vision) was limited to 5 minutes.
  5. The SQM-L reading was taken directly from M44 and mean value was taken based on 5 separate measurements.
  6. At 23.00 the city shuts down half of the streetlights on the small walking path leading to the observing spot used.

7.3.2010, 21.11 - SQM-L 17.70 (NELM ~4.85)- M44 invisible.
13.3.2010, 22.06 - SQM-L 17.98 (NELM ~4.99) - M44 fairly easily visible with averted vision.
13.3.2010, 22.36 - SQM-L 17.94 (NELM ~4.97) - M44 perhaps slightly more difficult than on the previous try.
13.3.2010, 23.06 - SQM-L 18.01 (NELM ~5.00) - M44 fairly easily visible.
13.3.2010, 23.36 - SQM-L 18.02 (NELM ~5.00) - M44 fairly easily visible.
13.3.2010, 23.56 - SQM-L 18.02 (NELM ~5.00) - M44 fairly easily visible.
14.3.2010, 21.36 - SQM-L 17.84 (NELM ~4.92) - M44 very difficult.


Naked eye limiting magnitude = (SQM reading - 8) / 2

The mighty few - the two missing NGC clusters

In 1863, G. P. Bond (director of the observatory at that time) published a list of 33 new deep sky objects discovered by astronomers who worked in the Harvard college observatory. These observers include George Phillips Bond himself (1825-1865), Phillip Sidney Coolidge (1830-1863), Horace Parnell Tuttle (1837-1923), and Truman Henry Safford (1836-1901). (As a side note, I'd like to note that in the 2010 book "Observing and Cataloguing Nebulae and Star Clusters" by Wolfgang Steinicke, there seems to be a typo regarding the age of Coolidge when he died. It says in the book that Coolidge "was born on 22 August 1830 and died in the civil war on 19 September 1863 being only 29 years old". Unless there are something wrong with the birth/death date, I'd say Sidney Coolidge died at the age of 33)

Bond's paper was published in the Astronomische Nachricten (No. 1453) but the paper had some quirks. First, the discovery of the two of our objects in questions NGC 2189 and NGC 2198 are credited as having been discovered by J. H. Safford. This is at least corrected (by whom?) in the copied version of the publication (J crossed and T added to the right side margin). The second one is, as everyone who's had a look at this particular dilemma, the position of the two missing NGC clusters in Orion. There are no coordinates for any of the clusters, only 1863 coordinates for the near by position stars! What a bummer. We know that the clusters were pretty certainly found with a magnification of 141 and field of view of 11'. Either there is something I'm not seeing here or there is something profoundly wrong with the original coordinates.


Object 7(a) & 7(b) - NGC 2189

"Two clusters, seen 1863 March 19 near two stars of the 10.11th magnitude, by J. H. Safford, with the Great Refractor [15 inch Merz refractor]. In Harvard Zones [IV]. Position of stars:

06h 04m 44.9s +01° 08' 37" (1863) = possibly GSC 131:1117
06h 05m 47.2s +01° 10' 02" (1863) = possibly GSC 131:1065

Not only are these two stars nearly 15' apart, there is no sign of any clusters in the area. It is also important to notice that Safford specifically mentions TWO clusters not a single one like the single NGC designation suggests. Safford's description "near two stars mag 10-11" is also fairly vague. Visual inspection of the region comes up pretty empty as well. 1908 paper by Pickering gives us coordinates of 06 12 22 +01 07 34 which is pretty much at the current non-ex position of NGC 2189. The asterisms discovered previously with the 15 inch refractor (1852-1853 for example) are pretty vague and are often very difficult to to discern from the background sky at all so in that aspect these clusters are a good match.


Object 8 - NGC 2198

"A cluster, see 1869 March 19, by J. H. Safford, between two stars in the following position. With the Great Refractor. In Harvard Zones [IV].

Star of 10.11 mag. 06h 06m 27.8s +01° 01' 10" (1863) = possibly GSC 131:870
Star of 9.10 mag. 06h 07m 12.7s +01° 00' 27" (1863) = possibly GSC 131:1266

What is between these two stars? A load of black space that's what! These two stars are separated by a mere 6'. Pickering's 1908 do not differ much from the current non-ex position of NGC 2198 just like with NGC 2189.


Simply from a visual observer's point of view, there is one possibility hanging in the air. A fairly good looking asterism can be seen more to the north, nearly in the middle of NGC 2189 and NGC 2198. The asterism is flanked by 9th magnitude HD 288493 and 10th magnitude HD 288534.

The position is however quite far away from the given positions of NGC 2189 and NGC 2198 and there is just one object - not three.

Unless someone takes a look at Safford's original observing logs like Dr. Harold G. Corwin suggest... I'm willing to go with the fact that these are nothing more than two very poor, uninteresting groups of few stars as suggested in the NGC/IC project home page. Sadly.