Image of the day

Captured by
David Marks

Lightning in the desert

My Account

New to Astromart?

Register an account...

Need Help?

Posts Made By: Herbert Kraus

September 10, 2005 08:25 PM Forum: Deep Sky Observing

Large Bright Open Clusters

Posted By Herbert Kraus

Those of you who -- like me -- enjoy observing deep-sky objects but are handicapped at your home location by skies that are compromised by urban pollution, might enjoy the type of object that has recently excited my interest: The galactic cluster that contains numerous bright or moderately bright stars scattered over an area that fills or exceeds the field of view of a low-power eyepiece. Some examples currently in our evening skies are:
IC 4665 in Ophiuchus (17:47:26.707 +5:42:54)
IC 4756 in Serpens Cauda (18:39:8.75 +5:26:16)
Stock 1 in Vulpecula (19:35:59.505 +25:11:11)
NGC 6940 in Vulpecula (20:34.7 +28:18)
NGC 752 in Andromeda (1:57:36 +37:40:0)
Stock 2 in Cassiopeia (2:15:0 +59:30:12)
If any of you has additional suggestions, I would be pleased to learn of them. Thanks.

September 17, 2005 12:53 AM Forum: Landscape Photography

Tokopah Valley, Sequoia N.P.

Posted By Herbert Kraus

Summer's over, and I get nostalgic for this place: August 2005 by the Marble Fork of the Kaweah River in the Tokopah Valley, Sequoia National Park.

December 8, 2005 09:31 AM Forum: Equipment Talk

A wire-retracting device?

Posted By Herbert Kraus

An inquiry to you inveterate tinkerers and modifiers of telescope equipment: In the field, the portable power supply for my go-to telescope contains a 12-volt battery and connects to the scope with a thin double wire. The wire's 25-foot length is ample to accommodate the scope's movements, but I sometimes trip over it in the dark and, as the scope slews and pans around in the azimuth, the wire winds awkwardly about the tripod legs. Where could I find some presumably spring-driven device that will hold the wire, play it out and retract it smoothly, like they have for laundry lines?

March 2, 2006 08:52 AM Forum: Beginning Astronomy?

Re: Seeing some deltails in galaxies?

Posted By Herbert Kraus

Mike: For what it may be worth, let me give you my experience with a Celestron 8-inch SCT, but please also note that I am an elderly fellow whose vision, once very acute, is no longer what it was when I was young. In mediocre skies, with urban light pollution, etc., all galaxies that I can see are nothing but fuzzy smears. On my occasional outings to good dark sky sites (Mt.Pinos or the California desert), I can see many more galaxies and I can readily see their shapes (round for face-on spirals, cigar-shaped for M82 and various edge-on spirals, oval for M81 and other spirals tilted to our line of sight and most ellipticals); but only very rarely have I seen such structural details as the spiral arms in M51 or the dust lane in M104 (the Sombrero), and then only in the most prominent of these galaxies, like those I've mentioned, never in the vast majority of galaxies which are rated magnitude 10 or dimmer.

March 13, 2006 10:19 AM Forum: After Dark

What did I see?

Posted By Herbert Kraus

Observing the fine triple star Sigma Orionis last night (March 12), I saw an object moving within my field of view. I suppose it must have been an artificial satellite, but because its behavior differed from what I've usually seen for these objects, I am asking what it was. At some time between 9:00 and 10:00 pm PST on 3/12/06, this object appeared in the starfield around R.A. 5h 39m, decl. -2ยบ36', moving in a general east-south-easterly direction, but instead of presenting a steady glow it was blinking on and off. Mostly it was off, but every 3 seconds or so its light came on for about half a second at the brightness of a star of about 8th or 9th magnitude (I compared it to the star at the eastern point of the arrow-like asterism that includes Sigma Orionis in its middle). The object moved fairly slowly, covering about 3 to 5 arcminutes between each of its blinks that occurred about 3 seconds apart. What was I seeing?

April 13, 2006 11:38 PM Forum: Deep Sky Observing

Observing Open Clusters

Posted By Herbert Kraus

Being a deep-sky observer for whom most galaxies and nebulae are inaccessible, I am posting extracts from the logs of a recent observing session of mine for those of you, if anyone, who is as fond of viewing galactic clusters as I am. For others, this post will be much too long.
On Tuesday, April 11, I went stargazing at Cottonwood Springs, Joshua Tree National Park (California), with my 8-inch Celestron SCT. The seeing was substantially compromised by the light of the 12-day old moon, so that the glow of the milky way which is usually apparent to the naked eye at that 3,000-foot high location was completely washed out. However, the air was still and free of moisture, offering enough transparency for good views of the season's many open clusters, and I therefore restricted my viewing to those objects. Mostly I used a Parks Gold Series 20 mm eyepiece that I recently acquired for viewing clusters, and I occasionally switched to a Meade 24.5 mm SWA eyepiece for wider fields of view.
The season's prominent open clusters listed by Messier (M35, M36, M37, M38, M41 and M47) were all brilliant, as were the less prominent M46, M48 and M50. After admiring these and other old friends, I inspected the following clusters that I had not studied before:
NGC 1662 in Orion, seen at 102x, showed me about 12 stars within a diameter of about 15 arcminutes, of which 7 were fairly bright and the others rather dim. I likened the shape and orientation of this cluster to NGC 2244, the open cluster at the core of the Rosette Nebula. Archinal & Hynes says this cluster contains 59 stars within a diameter of 12 arcminutes, suggesting that I missed seeing a swarm of dimmer stars among the dozen I saw.
NGC 2194 in Orion looked like a small, dim swarm of numerous stars. This is consistent with Archinal & Hynes which states that this 8.5-magnitude cluster contains 194 stars within a diameter of 9 arcminutes. An old Lowell Observatory photo on page 1345 of volume 2 of Burnham's handbook shows the cluster as just barely distinguishable from the numerous field stars that surround it.
NGC 1778 in Auriga, viewed at 102x, appeared as a small open cluster in which an equal-magnitude double star is prominent. An observer of the Webb Society who viewed the cluster in a 10-inch scope also noted it as a "Small group containing several doubles including an equal 10 mag pair at the centre."
I noted NGC 2281 in Auriga as a "brilliant" open cluster, whose stars filled most of the 30-arcminute field of view of my eyepiece at 102x.
Viewing NGC 2251 in Monoceros at 102x, I saw 15 or more stars of various magnitudes stretched east-west across about 75% of my eyepiece's 30-arcminute field of view. This is consistent with the observations of the Webb Society's observer who described NGC 2251 as "25 stars in a streak; 20' x 5' diameter." On the other hand, Archinal & Hynes refers to this as a cluster of 92 stars within a diameter of only about 10 arcminutes.
Observing NGC 2324 in Monoceros at 83x, I first saw it as a Y-shaped group of several stars of approximately equal magnitudes, among some outlying star of different magnitudes. When I switched eyepieces to 102x, I saw a small dim swarm of stars around one of the brighter outliers. This swarm is apparently the true NGC 2324, as confirmed by the data in Archinal & Hynes and the Webb Society handbook.
NGC 2232 in Monoceros was too extensive for the 30-arcminute field of view of the 20 mm eyepiece. Seen at 83x in the 24.5 mm eyepiece, it was a fairly large scattering of stars, some of which were quite bright. This is consistent with the Webb Society observer's description of NGC 2232 as "15 stars in 20' x 10' field; bright," and with Archinal & Hynes' rating of it as a cluster of just 20 stars in a field whose diameter is 53 arcminutes, with a total visual magnitude of 4.2
NGC 2401 in Puppis showed me a very dim small swarm near two somewhat brighter stars. Had I mis-identified the cluster? Archinal & Hynes rates this as a 12.6-magnitude cluster of 20 stars within a 2-arcminute diameter field.

May 7, 2006 11:21 AM Forum: Refractors

Deep-Sky Observing with Refractors

Posted By Herbert Kraus

This is a question to you experts in optical matters from an avid deep-sky observer (viewing, not imaging) who is, however, "optically challenged," having never been inclined to study the physics or other esoterica of telescopic optics: I understand that apochromatic refractors are preferred over achromatic ones because they bring most colors to focus at the same point and thereby avoid the halo of purple or other color around planets and the moon. But what about viewing clusters, nebulae and galaxies? Assuming good quality optics and workmanship in other repects, does the apochromat have a significant advantage over the achromat as to these objects also? Or could it be that this question doesn't arise nowadays because reflectors are preferred over refractors for deep sky observation? And what about observing double stars; does the apochromat have an advantage over the achromat here too? I thank anyone who can enlighten me on these questions.

May 7, 2006 03:59 PM Forum: After Dark

Together at Last: the Ring and the Comet

Posted By Herbert Kraus

A head's-up for those of you in North America who expect clear skies tonight, Sunday, May 7: When Lyra rises tonight, the Ring Nebula (M57) and Fragment C of Comet Schwassmann-Wachmann 3 will apparently be near enough to each other to fit within the same field of view of a low- to medium power eyepiece. Starry Night Pro tells me that the two will be well within the same 98-arcminute field of view of the 15 mm Panoptic eyepiece in my 80 mm f 7.5 refractor, and that the comet's visual magnitude will be 6.9. The meeting place of these objects is just east of Beta Lyrae ("Sheliak"). Clear skies to all of you.

July 23, 2006 10:59 AM Forum: Pictures of Me and My Telescope and........

My 60-inch telescope and I

Posted By Herbert Kraus

I am submitting two pictures taken at the Los Angeles Astronomical Association's July 21 star party at the 60-inch telescope on Mt. Wilson. For you history buffs: when this instrument was installed in 1908 it was the largest telescope in the world, until 1917 when the 100-inch Hooker telescope went on line next door. Here's the first photo (please forgive the vanity shot).

July 26, 2006 06:27 PM Forum: Beginning Astronomy?

Re: My thoughts about go-to

Posted By Herbert Kraus

In expressing these opinions about "go-to" observing in this forum for beginners, has anyone pointed out that searching for deep-sky celestial objects by star-hopping, a method preferred by many seasoned observers, is not nearly as workable in the polluted urban and suburban skies available to most of us as at dark sky sites? If someone has already mentioned this, forgive this redundance. In my home skies, for example, I can see few stars fainter than 2nd magnitude; and if I were a beginner and not someone who's memorized the appearance of most constellations in my skies many years ago, star-hopping would be of limited value to me.