KW Sagittarii
- Constellation: Sagittarius
- Right Ascension: 17h 52m 00.72665s
- Declination: −28° 01′ 20.5622″
- Distance: 1,359 - 6,000+
- Apparent Magnitude: 8.59 - 11.0
A very large red giant star located withing the constellation bounds of Sagittarius. If it was located where our Sun was, it would extend out past Mars. A pulsating long period variable star with a long period of around 670 days. It varies in magnitude from 8.5 to 11.0 over its long period, with a smaller magnitude pulsation period of around a third of a day. There are no reliable distance measurements other that its far enough away that parallax measurements are currently unreliable. It is the reddish brighter star located near the center. A rich star field for a back drop as we look towards the center of our Milky Way galaxy.
- Details
- Category: Stars
- Telescope: Explore Scientific 127 Refractor
- Camera: ZWO 2600 MM
Star HD 84406
- Constellation: Ursa Major
- Right Ascension: 09h 47m 30.71
- Declination: +63° 14` 53.3
- Distance: 246 ly
- Apparent Magnitude: 6.94
HD 84406 is located in the constellation of Ursa Major, and a yellow star of spectral type G, and shines at a magnitude of 6.9, just dimmer than a person can see without optical aid.
What is special about HD 84406? Actually not too much as stars go, but that is a good thing as it was used for the initial focusing of the new James Webb space telescope.
Some of the constraints were the star would have to be in the field of view for the telescope for the entire collimation of the mirrors. The star couldn't be too bright which would cause issues with the sensors. Also the star needed to be in an uncrowded area by other stars. And of course the star needs to be stable with a constant magnitude.
- Details
- Category: Stars
- Telescope: GSO RC10
- Camera: ZWO 2600 MM
Wolf 359 (2022)
- Constellation: Leo
- Right Ascension: 10h 56m 28.99s
- Declination: +07° 00′ 52.0″
- Distance: 7.9 ly
- Apparent Magnitude: 13.5
A red dwarf star located in the constellation of Leo, its the reddish star located in the center of the image. It's name comes from astronomer Max Wolf who studied that exhibit large proper motion across the sky. A star with a large proper motion appears to move across the sky over the years. Most are relative close stars that their movement can be measured over the years.
One of the closer stars at 7.9 light years, but because its one of the dimmest of the local red dwarfs, its magnitude is a faint 13.5.
Image of Wolf 359 taken in 2015, compared to its current location shows its movement over the years.
- Details
- Category: Stars
- Telescope: GSO RC10
- Camera: ZWO 2600 MM
Trio of Messier Open Clusters
One classification of open clusters is the Trumpler classification. It consists of 3 parameters, the first is the degree of concentration.
I - Detached clusters with strong central concentration.
II - Detached clusters with little central concentration.
III - Detached cluster with no noticeable concentration.
IV - Clusters not well detached, but has a strong field concentration.
The second parameter is the range of brightness.
1 - Most of the cluster stars are nearly the same apparent brightness.
2 - A medium range of brightness between the stars in the cluster.
3 - Cluster is composed of bright and faint stars.
The last parameter categorizes the number of stars in the cluster.
p - Poor clusters with less than 50 stars.
m - Medium rich cluster with 50-100 stars.
r - Rich clusters with over 100 stars.
If the cluster any type of nebulosity, the letter "n" is added to the last parameter.
First up is Messier 34, located in the constellation of Perseus. Consisting of over 100 stars, in a space of a diameter of 14 light years. It is some 1,500 light years distance and shines at an apparent magnitude of 5.5 at an estimated age of 200 million years.
- Details
- Category: Open Clusters
Read more: Trio of Messier Open Clusters
- Telescope: GSO RC10
- Camera: ZWO 2600 MM
Messier 41 (2021)
- Constellation: Canis Major
- Right Ascension: 06h 46.0m
- Declination: −20° 46′
- Distance: 2,300 ly
Messier 41 is an open cluster located in Canis Major near Sirius. The cluster contains some 100 members in a diameter of 25 light years. Estimated age of the cluster is around 200 million years. It is expected to remain as a cluster for 500 million years before dispersing. Brightest of the stars is an orange giant near the cent of the cluster. K3 type star, it has a magnitude of 6.3 and is 700 times more luminous than our Sun.
- Details
- Category: Open Clusters
- Telescope: Explore Scientific 127 Refractor
- Camera: ZWO 2600 MM
Messier 45 (2021)
- Constellation: Taurus
- Right Ascension: 03h 47m 24s
- Declination: +24° 07′ 00″
- Distance: 444 ly
Messier 45, one of the more famous open clusters. Often called the Pleiades or the Seven Sisters, with the name Pleiades coming from Greek mythology. The cluster has been known since ancient times, and can be seen as a grouping of 6-7 stars, so it was interesting that Charles Messier included it in his catalog of objects that are not a comet, but could be mistaken for one.
The cluster is surrounded by a reflection nebula that the group is currently passing through, and not related to its original birth in a compact nebula. The cluster consist of at least 1,000 stars located in a radius of 8 light years. The cluster is dominated by hot blue luminous stars, but also contains many brown dwarfs that are not massive enough to initiate nuclear fusion. The estimated age of the cluster is around 100 million years, and its expected to take 250 million years to disperse due to gravitational interactions.
- Details
- Category: Open Clusters
- Telescope: Explore Scientific 127 Refractor
- Camera: ZWO 2600 MM
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