COTM: Scutum

Albert Brakel

Scutum the Shield is located in a very rich part of the Milky Way, between Aquila and Sagittarius. Originally it was named by Hevelius in the 17th Century as Scutum Sobiescianum, the shield of King John Sobieski of Poland. Hevelius, you might have guessed, was also a Pole. It was the most lasting, but not the only attempt to name constellations after royalty in recent centuries. There was, for example, the Hand and Sceptre of Justice (of French King Louis XIV), now Lacerta the Lizard. And Edmund Halley tried to invent the small constellation of Cor Caroli (Heart of Charles) after English King Charles II, centred on the star Alpha Canum Venaticorum, but today the name survives only as the common name of that star.

Scutum does not have an easily recognizable pattern of stars, and the brightest one, Alpha Scuti, is only magnitude 3.9. However, you can easily find the location of Scutum by its most visible feature, the Scutum Star Cloud. While not as spectacular as the Great Sagittarius Star Cloud to its south, it is more prominent than the Norma Star Cloud, and is readily found with the unaided eye, unless your light pollution problems are really bad.

My observations of this small constellation were made with a Celestron C8 20 cm SCT from inner suburban Downer.

Let’s start off with the best-known deep sky object (DSO) in Scutum, the rich M11 open cluster, or Wild Duck Cluster (RA 18h 51.1m, Dec –06° 16’), visible in finderscopes. The middle region is densely packed with stars – 83 per cubic parsec, if one reference is to be believed (a parsec is three-quarters of the distance between here and Alpha Centauri). A pale yellow brighter star stands out from the rest. Some irregular dark patches could be seen, that were more conspicuous with 117x and higher powers. This central region is separated by a sparsely populated gap from a wider ring of stars arranged in straight-line segments in the form of a pentagon with one side missing. The cluster was given its name by the 19th Century observer Admiral Smyth, who thought it resembled a group of wild ducks in flight. I find it hard to see this resemblance, but maybe he was looking at two sides of the outer pentagon that form a V shape. Whatever it reminds you of, this beautiful cluster would have to be on anyone’s list of the sky’s top 10 open clusters.

R Scuti (18h 47.5m, -05° 42’) is a variable star one degree NW of M11. It is one of the most widely observed variables in the sky, and has been known since 1795. It belongs to a class of semi-regular variables showing complex behaviour. There are two superimposed periods of 144 and 1300 days, so that it can reach a maximum as bright as magnitude 4.8, and drop at minimum to mag. 6 or even fainter than mag. 8. Check to see if it is brighter or fainter than the two mag. 6 stars 30’ to the SE. When I looked in on it, it was brighter than them, and a nice orange color.

NGC 6664 (18h 36.7m, -08° 13’) can be found in the same low-power field as Alpha Scuti, half a degree east of the star. It is a loosely scattered open cluster, with about 15 or so middling stars standing out from among the fainter ones. Its brightest member is about mag. 10.

M26 (18h 45.2m, -09° 24’), 2½ degrees SE of NGC 6664, is a small open cluster with 3 or 4 brighter stars set amid a luminous haze of fainter and unresolved stars. The brightest one is on the central preceding (W) edge. There is a small patch of luminosity with faint stars S preceding the main cluster, and separated from it by a dark rift. I tried 5 different magnifications, of which 117x was best in the prevailing conditions. Hartung said it is rather inconspicuous with small apertures. He was right.

Two degrees further ENE, globular cluster NGC 6712 (18h 53.1m, -08° 42’) is not as bright as some, shining at mag. 8.2. It appeared grainy textured, and moderately concentrated towards the centre. No stars were definitely resolved at any magnification up to 235x, but occasionally I thought I glimpsed some set in the roundish 7’-diameter disk of grey light.

In the same low power field and 24’ ESE, faint planetary nebula IC 1295 (18h 54.6m, -08° 50’) was quite invisible until an OIII filter was used, when it appeared as a dim, roundish ghostly glow. With listed integrated magnitudes of 12.5 and 15.0 in two separate references, I’m surprised I could see it at all, but with the mag. being so uncertain, it would seem both of them underestimate the brightness. I detected no noticeable brightness gradient or central star.

Struve 2373 (18h 45.9m, -10° 30’) — this mags. 7.2/8.2 binary star comprises pale yellow and deep yellow constituents at 4.1” separation, enabling it to be resolved with 77x.

Struve 2325 (18h 31.3m, -10° 50’) is a wide double star with pale yellow and ashy components 12.3” apart, easily split with 77x and higher powers. It could also be split with 50x, but this was more difficult because the faint m.9.1 secondary is brought closer to the bright m.5.8 primary. Images show that the pair is immersed in the faint and diffuse reflection nebula IC 1287 that is illuminated by the binary. There was no chance of seeing this from my location, even with high magnification or with a broad-band nebular filter — a clear, dark night with a larger aperture would be necessary.

Awards 2005

Andrew White

CAS LIFE MEMBERSHIP — LEN WILLIAMSON

Every now and then, the CAS decides to bestow the ultimate honour on one of its members — CAS Honorary Life Member. This award is given to members who have dedicated years to astronomy and the Society. In the entire history of the CAS there have only ever been six Life Memberships at any one time. Well, now there are seven with the induction of Len Williamson into their esteemed ranks!

I guess that many of the newer members may not be familiar with Len or the work that he has done over a period of several decades. Len has been a prolific variable star observer since the 1950s, and has contributed countless articles on the subject to this and other astronomical journals — a check through past issues of Southern Cross back to 1988 revealed 34 articles, and there would have been more before then. He has been a very familiar and regular speaker at CAS meetings. For his outstanding work, Len was nominated for the Berenice Page Medal in 1994.

As a teenager, some of my earliest memories of CAS meetings involve Len with his great detail and his inspiring passion and enthusiasm for the work he was doing. As if spending years recording thousands variable star magnitudes wasn't impressive enough, I should point out that all of Len's work was accurately determined by eye ...no photometers or CCDs … just a telescope and a human eye! That's what dedication is all about!

While age may have slowed Len down a bit now, I'm sure his enthusiasm and love of astronomy hasn't waned in the slightest! On behalf of all those members of the CAS who listened to and read your tales of variable stars throughout the years … "Many, many thanks, Len!"

CAS Awards 2005

The CAS Awards were inaugurated in 2002 to acknowledge the individual efforts being made on behalf of the Society by its members. (As the award has printed on it: "In appreciation of services to the Society".) The awards are presented each year at the CAS dinner.

Nominees for the CAS Awards are proposed and elected by the Committee, and are presented to individual members who (in the Committee's opinion) have provided valuble service to the Society.

In 2005 the CAS Award winners are Darren Osborne and Shirley McKeown.

As most of you will remember, the CAS was left homeless after the January 2003 bushfires. Within weeks of the fire, Darren Osborne had secured a new meeting place for the Society at his work place in the CSIRO Headquarters in Campbell. Not only did the CSIRO serve as our new meeting place for nearly two years, Darren personally stayed back at work each meeting night to open the doors and then to lock up after we all (eventually) went home. Well done Darren and "Thanks" again on behalf of the whole Society!

Everyone in the Society knows Shirley McKeown, but not everyone realises just how much she really does! Shirley has been the Society’s Treasurer for the last 8 years! In this time she has had to contend with and sort out insurance issues, CAS merchandising (binoculars, T-shirts, coffee mugs, badges, etc.) and now Society memberships. In addition to doing all that, and reporting to both the Committee and General Meetings each month, Shirley is also one of our most regular attendees at the monthly Journal foldings and public viewing nights. This is surely a record of hard work that few can match! A big and continued "Thanks" from the Society, Shirley!

Andrew White

President — Canberra Astronomical Society

The Mars 100

Albert Brakel

Inspired by this year's (2005) John Morland Nebulous Award for observing features on Mars at the coming opposition season, and by the Lunar 100 of Charles Wood in the April 2004 Sky & Telescope, I have compiled this list of 100 Martian features as an observing challenge.

So that this list can be used at any future opposition, it contains features from both polar regions, even though not all will be visible at every observing season. Remember also that a feature prominent at one opposition may be less prominent or invisible at another, because of changing dust cover on Mars.

The items are arranged in very roughly increasing order of difficulty, but the actual difficulty will depend on which pole is pointed Earthwards and by how much, how far away the planet is, the conditions on Mars, and the equipment used. The detectability of many features will be greatly enhanced by color filters.

The list starts with three easy unaided eye observations (finding Mars, its color, and its prograde/retrograde motion), and ends with the Martian moons Deimos and Phobos. Using the list should help you get to know Mars better, so try it - how many of the following can you find visually?

Review: University Optics König Eyepieces and Klee Barlow

Ian Ogilvie

Introduction

I must commence this review by stating that eyepiece preferences and selection are very personal things. Everybody's eyes are different and while reviews such as this one are useful, I recommend that if all possible you try before you buy.

I do not have any association with University Optics (UO) or any of the suppliers mentioned in this review. The comments in this review are merely my personal observations.

To assist the reader place my comments in context, the König eyepieces have been reviewed on the basis of my relatively limited experience. While I have done quite a bit of observing over the last couple of years, in no way do I consider myself an experienced observer. I have been most fortunate to have the opportunity to use a number of telescopes up to 20”, using a variety of interesting eyepieces from classic orthoscopic types through to some of the magnificent Televue products.

Background

After 30+ years casual observing with a couple of different scopes, I joined the local astronomical society several years ago and had the opportunity to look through a variety of high quality eyepieces during deep sky nights. The inevitable result was that I started looking to upgrade the eyepiece set I was using with my 8” F/6 Dob. My eyepiece set at this stage comprised Celestron brand, mid 90's vintage; 25mm SMA, 32 & 10mm Plossls and a 2x Ultima Barlow. I started the search process by defining the basic selection criteria:

1. Max cost $150 per eyepiece. (If only I could afford Naglers!)
2. Min Apparent Field of View (AFoV) of 60°. (Helps with a hand-pushed Dob).
3. Reasonable edge performance at F/6.
4. Range of focal lengths suitable for 1200mm focal length at F/6.
5. Eye placement not critical. (Some EP's have fairly critical eye placement requirements and as a result can be quite tiring to use).

Having done some initial research via the Web, I was in Melbourne on business and happened to drop into BATSC in Heidelberg looking for a “large” finderscope. I found BATSC most helpful, and having decided on a 70mm F/5 refractor suitable for modification to a finderscope configuration, I just had to spend some time looking at available eyepieces. I acquired a 20mm 66º AFoV eyepiece that looked remarkably similar to an Orion Expanse type. I found the shorter FL eyepieces in this range did not suit my eyes due to “kidney beaning”.

While I found the eye relief and eye placement characteristics of this eyepiece made it very easy and relaxing to use, I also found the focused image just a little too soft for my liking.

The next eyepiece I acquired was an 11mm 80° AFoV unit from Andrews Communications whom I also have found most helpful. I believe this unit is manufactured by ZhiTong Industries in China. I quite like this eyepiece although the usable AFoV is more like 70° and it does not like being barlowed.

My quest then led me to University Optics. I was acquiring some ATM parts from them and also ordered a 16mm König eyepiece. I was most impressed with this eyepiece, the inevitable result being an order for the 24 and 12mm versions and the 2.8x Klee Barlow.

My reasoning for the specific selection of eyepieces and Barlow was that by this stage I was also in the design phase of an 8” F/6 "stringscope" dob and this eyepiece/Barlow set, as well as being compact and light weight, would give me a nice set of Field of View (FoV)/Exit Pupil/Magnification numbers as listed in the table below:

Description

All units are of high quality construction and very nicely finished. They are of basic construction however, in that they do not come with eye guards, have smooth sides devoid of any form of non-slip grip and there is no safety undercut on the barrel. The lenses appear to be fully multicoated as advertised, with blackened edges. The Königs were supplied in well-made cardboard boxes with plastic end caps for both ends. The Klee came in a similar box but only a lower end cap.

The Klee Barlow is a remarkably compact type and is somewhat smaller and lighter than the compact Celestron Ultima Barlow as shown in the photograph.

The Klee Barlow has a small field lens when compared to the Ultima as shown. This may be one of the factors contributing to this Barlow’s reported vignetting tendency. This photo also shows to advantage the very high quality coatings used in the Ultima series eyepieces/Barlow. The photo appears to indicate the Klee coatings have a higher level of reflectivity than the Ultima.

The eyepiece prices as listed on the UO Web Site on 29 March 2005 are:

• Klee Barlow, 12mm König, 16mm König all $79.95 USD
• 24mm König $99.85 USD

Performance

I have used all three eyepieces and Barlow for the 18 months or so in my 8-inch F/6 dob, as well as my Saxon 70mm F/5 refractor (finderscope). I have also tested them on a limited basis in Meade and Celestron SCT’s at F/10.

A note of caution. I have also tried these eyepieces with a 30mm F/4 binocular objective set up as a finderscope. The 24mm and 12mm are still usable (just) while the 16mm completely “falls apart” at this F-ratio and I found it totally unusable.

My interest is predominately with deep sky objects; as a result the impressions I have gained with these eyepieces have been heavily influenced by their performance in this area.

On deep sky objects these eyepieces seem to perform quite well. As well as offering performance comparable to high quality Plossl types, they offer an additional 10° AFoV that I find quite helpful when star hopping, and while not an ultra wide FoV, the extra 10° certainly provides a more “immersive” experience than a Plossl can offer.

When observing the Moon and planets, to avoid the astigmatism that is evident at F/6, I find I need to keep the object within the central 50% of the FoV. However, the situation changes when using the Klee Barlow when almost the entire FoV (95%+) becomes usable for high definition viewing. I have not seen any evidence of ghosting or internal reflections with bright objects.

As best as I can measure them, the AFoV and focal length for all three eyepieces are as advertised.

Overall these eyepieces could be considered similar to high quality Plossl type with a greater AFoV (60° as opposed to 50°-52°) and slightly increased eye relief. They do, however, appear to be more sensitive to reducing F-ratio. I have found them parfocal within 2mm and, when used with the Klee Barlow, almost perfectly parfocal.

24mm König II

This is a pleasant eyepiece to use with just sufficient eye relief to allow the use of glasses if required. It is not fussy about eye position, and I have not seen any sign of kidney bean or blackout.

Stars snap into focus as very tight pinpoints with excellent contrast and no evidence of ghosting or internal reflections. I have not seen any evidence of field curvature, but it does suffer from increasing astigmatism at the edge of the field with reducing F-ratio. However, it is quite useful at F/5, good at F/6 and excellent at F/10.

12mm König II

I have listed this eyepiece next as my comments are almost identical to the 24mm with the exception of eye relief which will not allow the use of glasses. The eye relief is approaching eyelash distance, however, due to the size of the eye lens I find I can, with care, position my eye so as to keep eyelash oil away from the lens.

Due to its small size and tapered top, it can be somewhat difficult to grasp and remove from focuser units, particularly when wearing thick gloves.

16mm König II

This eyepiece is somewhat different to the other two in that it has a larger AFoV of 68°. I am not sure why UO have done this, as the effect of the larger field stop is a reduction of eye relief to inside eyelash distance. In addition I have found the last 10% or so of the AFoV almost unusable at F/6 due to astigmatism.

Ultimately, to make the eyepiece easier to use, I fabricated a new field stop of reduced diameter to provide a new AFoV of 60°. This has increased the eye relief to a more usable level, and the area outside 60° that was affected by significant astigmatism is now hidden by the field stop.

Like the other König’s, stars snap into focus as very tight pinpoints in this eyepiece, with excellent contrast and no evidence of ghosting or internal reflections. I have not seen any evidence of field curvature, but like the other UO Königs it does suffer from increasing astigmatism at the edge of the field with reducing F-ratio. It is quite useful at F/6 and excellent at F/10. I personally find the astigmatism displayed by this eyepiece excessive at F/5.

2.8x Klee Barlow

This unit is very small and light, it does not appear to introduce any undesirable aberrations and is well matched to the three König eyepieces in this review.

A note of caution: I have seen comments in various Web sites that this Klee Barlow can introduce vignetting with some eyepieces and F-ratios. I have noted it severely vignettes my 11mm Andrews (ZhiTong) UWA eyepiece. However, with the three UO Königs I have not seen any evidence of this.

Apart from the increasing magnification, the most noticeable effect of this Barlow is all three pieces are almost exactly parfocal and the edge of field astigmatism completely disappears. For planetary use I have found König/Klee combination very sharp and usable almost right to the edge.

Summary

Liked

• Price
• Weight/Size
• Sharpness and Contrast
• Performance above F/6
• Wider AFoV compared to a Plossl
• Nicely matched set with or without the Klee Barlow

Not Liked

• No eye guard.
• No non-slip grip.
• No safety undercut.
• 12mm is very low profile and can be hard to grasp when wearing gloves. Its profile also makes it hard to fit dew heater elements.
• Klee Barlow only came with lower end cap.
• 16mm field stop too large for comfort.
• Significant astigmatism below F/6.

Knowing what I know now, would I make the same decision again?

For me, the answer is yes, as this will provide a balanced and complete eyepiece set for my F/6 “stringscope”.

Overall

I have found the UO König II eyepieces and Klee Barlow covered in this review to be a high quality set of eyepieces with a good performance/price ratio subject to the inherent F-ratio/eye relief limitations.