January 19, 2025

M13 – Globular Cluster in Hercules

M13 – Globular Cluster in Hercules

Telescope: Meade SN10 at f/4, Orion Atlas EQ-G

Camera: Full Spectrum Modified Nikon D810

Filter: GSO IR Blocking Filter

Guide scope: Williams Optics 50mm, ASI290MM mini, PHD

Exposure: 109x20sec, ISO 200, saved as RAW

Darks: None (dithered every 4 images)

Flats: 32×1/50sec, tee shirt flats taken at dusk

Average Light Pollution: Red zone, fair transparency

Lensed Sky Quality Meter: 18.5 mag/arc-sec^2

Stacking: Mean with a 1-sigma clip.

White Balance: Nebulosity Automatic

Software: Backyard Nikon, Nebulosity, Deep Sky Stacker, Photoshop

This is M13, the Great Cluster in Hercules. Also in the picture is the galaxy NGC 6207 (Mv 11.6) in the upper left corner, and about halfway between NGC 6207 and M13 is the tiny galaxy IC 4617 (Mv 15.2) . If you look carefully at M13 you can see a dust lane to the lower left of the cluster. This is a very unusual feature for globular clusters and it is not clear if this is actually associated with M13 or simply lies in the line of sight with the cluster.

M13 currently rises in the northeast during the early evening.

Sigma Orionis – Multiple Star System in Orion

Sigma Orionis – Multiple Star System in Orion

Telescope: Unitron 155c 4” f/15

Camera: Canon EOS Ra, Interval Timer (no computer)

Filter: 2” GSO IR Cut Filter

Guide scope: None

Exposure: 32x1sec, ISO 800, saved as RAW

Darks: Internal (Long Exposure Noise Reduction)

Flats: None

Average Light Pollution: Bortle 8

Stacking: Mean with a 1-sigma clip.

White Balance: Nebulosity Automatic

Software: Backyard EOS, Deepsky Stacker, Nebulosity, Photoshop

Sigma Orionis is one of my favorite fields in the winter and spring sky. Sigma itself can be easily spotted with your unaided eye as a modest star just south of the easternmost star in Orion’s Belt; Alnitak. In a small telescope Sigma shows two nearby companions just off to the northeast as well as a wide pair off to the northwest (Struve 761). Close examination in a larger telescope shows a third companion to Sigma close by to the southwest, making Sigma a quadruple star system, and the southern star of the northwestern pair splits into a beautiful close pair of equal stars, making this a wonderful field of 7 closely arranged stars. (The brightest component of Sigma is actually a close binary system, making this a quintuple system!) During the winter months I always take a minute to stop by and to visit these old friends and I often use them to take a quick peek at the quality of the optics in a newly acquired telescope.

Sigma Orionis is currently well placed high in the southwest at dusk.

Earthshine – 9:00pm 4/3/2022 EDT

Earthshine – 9:00pm 4/3/2022 EDT

Telescope: Unitron 155c 4” f/15

Camera: Canon EOS Ra, Interval Timer (no computer)

Filter: 2” GSO IR Cut Filter

Exposure: 16x2sec, ISO 1600, saved as RAW

Seeing: Fair, 3/5

White Balance: Nebulosity Automatic

Software: Registax, Nebulosity, Photoshop

After taking a set of images of the crescent moon I decided to try and capture the beautiful Earthshine. The source images were gorgeous without a hint of color fringing. I had to remove a ghost image that indicates that the objective in this old Unitron does not have AR coatings. Processing also brought up a little bit of color fringing, but it is still very limited. Note the little star trail just above the moon that shows how far the moon moved during the time the source images were being taken.

Waxing Crescent Moon – 9:00pm 4/3/2022 EDT

Waxing Crescent Moon – 9:00pm 4/3/2022 EDT

Telescope: Unitron 155c 4” f/15

Camera: Canon EOS Ra, Interval Timer (no computer)

Filter: 2” GSO IR Cut Filter

Exposure: 32×1/50sec, ISO 800, saved as RAW

Seeing: Fair, 3/5

White Balance: Nebulosity Automatic

Software: Registax, Nebulosity, Photoshop

This is quick test image taken with my 60 year old Unitron 155c on its second night out. During this test I found that the 155c was much easier to point and to fine tune the field than I had expected. I was particularly interested in whether I could make fine adjustments in the R.A. as this model lacks the secondary fine R.A. control meaning that you cannot make fine adjustments in R.A. while the clock drive is installed. This turned out not to be a problem. The field of view of the full frame EOS Ra is large enough that pointing the scope was relatively easy. To make fine adjustments in R.A. I simply pointed the scope slightly west of the target, and then turned the clock drive off, letting it drift to the center of the field, and then turning the clock drive back on. Easy peasy. The clock drive itself performed flawlessly off of the 120vac output from my lithium ion battery pack, though I need to work on the polar alignment to get the best performance from it. It is certainly plenty good enough for visual and if I get serious about imaging with this scope I should look at mounting it on my Atlas.

M3 – Globular Cluster Canes Venatici

M3 – Globular Cluster Canes Venatici

Telescope: Meade SN10 at f/4, Orion Atlas EQ-G

Camera: Full Spectrum Modified Nikon D810

Filter: GSO IR Blocking Filter

Guide scope: Williams Optics 50mm, ASI290MM mini, PHD

Exposure: 28x20sec, ISO 200, saved as RAW

Darks: None (dithered every 4 images)

Flats: 32×1/50sec, tee shirt flats taken at dusk

Average Light Pollution: Red zone, fair transparency

Lensed Sky Quality Meter: 18.5 mag/arc-sec^2

Stacking: Mean with a 1-sigma clip.

White Balance: Nebulosity Automatic

Software: Backyard Nikon, Nebulosity, Deep Sky Stacker, Photoshop

M3 is a beautiful example of a globular cluster in a relatively lonely stretch of sky. The cluster is a member of the galactic halo and spends much of its time orbiting well outside the plane of the galaxy. It is presently 33,000 light years away from us, 40,000 light years from the galactic core, and 33,000 light years ‘above’ the galactic plane. Home to about 500,000 stars, M3 is relatively young as globular clusters go with an estimated age of 8 billion years.

M3 currently rises in the northeast during the early evening.

M67 – Open Cluster in Cancer

M67 – Open Cluster in Cancer – Unitron 142 3” f/16 Refractor

Telescope: Unitron 142 3” f/16 Refractor

Camera: ZWO ASI294MC (uncooled)

Filter: Meade IR Cut Filter

Guide scope: None

Exposure: 32x10sec, Gain 200, saved as PNG

Darks: None

Flats: Synthetic

Average Light Pollution: Red zone, poor transparency, haze

Lensed Sky Quality Meter: 18.4

Stacking: Mean with a 1-sigma clip.

White Balance: Nebulosity Automatic

Software: SharpCap Pro, Nebulosity, Photoshop

M67 is one of my favorite modest open clusters. It is located off to the east of the much larger and brighter M44 (The Beehive) and it is a bit harder to find, but worth the effort. M67 is very old for an open cluster with an estimated age of about 4 billion years. The stars in an open cluster are usually only weakly bound to the group and they slowly scatter as the cluster orbits the galaxy.

High in the southeast this time of year, M67 makes a fine target for modest telescopes and blossoms into a fine patch of stardust in large telescopes.

M46 – Open Cluster in Puppis

M46 – Open Cluster in Puppis – Unitron 142 3” f/15 Refractor

Telescope: Unitron 142 3” f/15 Refractor

Camera: ZWO ASI294MC (uncooled)

Filter: Meade IR Cut Filter

Guide scope: None

Exposure: 32x10sec, Gain 200, saved as PNG

Darks: None

Flats: Synthetic

Average Light Pollution: Red zone, poor transparency, haze, low altitude

Lensed Sky Quality Meter: 18.2

Stacking: Mean with a 1-sigma clip.

White Balance: Nebulosity Automatic

Software: SharpCap Pro, Nebulosity, Photoshop

M46 is one of several relatively bright open clusters that grace the evening sky in winter and early spring. This cluster also sports a beautiful little planetary nebula (NGC 2438) in the foreground. This little nebula looks quite stunning in a modest size telescope with the rich open cluster in the background. I was pleasantly surprised to see that I could capture the nebula with a 3” f/15 refractor using only 10 second subs.

M46 currently lies in the southeast during the early evening.

M51 – The Whirlpool Galaxy in Canes Venatici

M51 – The Whirlpool Galaxy in Canes Venatici

Telescope: Meade SN10 at f/4, Orion Atlas EQ-G

Camera: Full Spectrum Modified Nikon D810

Filter: GSO IR Blocking Filter

Guide scope: Williams Optics 50mm, ASI290MM mini, PHD

Exposure: 139x20sec, ISO 200, saved as RAW

Darks: None (dithered every 4 images)

Flats: 32×1/50sec, tee shirt flats taken at dusk

Average Light Pollution: Red zone, fair transparency

Lensed Sky Quality Meter: 18.5 mag/arc-sec^2

Stacking: Mean with a 1-sigma clip.

White Balance: Nebulosity Automatic

Software: Backyard Nikon, Nebulosity, Deep Sky Stacker, Photoshop

M51 is a beautiful face-on spiral galaxy in Canes Venatici, just south of Alkaid, the bright star that lies at the eastern end of the Big Dipper. The spiral arm that appears to connect M51 to the nearby companion (NGC 5195) is a bit of an illusion. The companion actually lies behind M51, and if you look closely you can see that the spiral arm is silhouetted against the background galaxy. Modern observations and computer modeling suggest that the companion has made at least two passes through the main disk of M51. During the first, it approached M51 from behind, passed through the face of the galaxy, swung around in an orbit that took it in front, and then back through the disk where it lies now behind M51. These passes set off bursts of star formation that gives the arms of M51 their beautiful blue color.

M51 currently rises in the northeast during the early evening.

M3 – Globular Cluster Canes Venatici

M3 – Globular Cluster Canes Venatici – Unitron 142 3” f/15 Refractor

Telescope: Unitron 142 3” f/15 Refractor

Camera: ZWO ASI294MC (uncooled)

Filter: Meade IR Cut Filter

Guide scope: None

Exposure: 32x10sec, Gain 200, saved as PNG

Darks: None

Flats: Synthetic

Average Light Pollution: Red zone, poor transparency, haze, low altitude

Lensed Sky Quality Meter: 18.0

Stacking: Mean with a 1-sigma clip.

White Balance: Nebulosity Automatic

Software: SharpCap Pro, Nebulosity, Photoshop

M3 is a beautiful example of a globular cluster in a relatively lonely stretch of sky. The cluster is a member of the galactic halo and spends much of its time orbiting well outside the plane of the galaxy. It is presently 33,000 light years away from us, 40,000 light years from the galactic core, and 33,000 light years ‘above’ the galactic plane. Home to about 500,000 stars, M3 is relatively young as globular clusters go with an estimated age of 8 billion years.

This is one of a series of ‘just for fun’ images taken with my 50 year old Unitron 142 3” f/15 refractor. I was pleased to find that the overall tracking quality of this mount is comparable to many modern mounts suggesting that it could be used for basic imaging using modern camera and processing techniques. So far the results have been surprisingly good and a lot of fun!

M3 currently rises in the northeast during the late evening.

The Full Worm Moon – 10:00pm 3/17/2022 EDT

The Full Worm Moon – 10:00pm 3/17/2022 EDT

This is an excellent example of the high resolution performance of the Unitron 142. I was pleasantly surprised by the lack of color fringing with this relatively long f/ratio scope. Note the lunar terminator sweeping across the southern highlands, indicating that the moon is passing north of the Earth’s shadow.