Category: Astronomy

Sky-Watcher Starlux 190mn Maksutov Newtonian Review

SkyWatcher 190MN Maksutov-Newtonian: A Stellar Performer

The SkyWatcher 190MN is a unique telescope that blends the strengths of Maksutov and Newtonian designs. This hybrid approach aims to deliver sharp images with a wide field of view, making it a compelling option for both visual astronomy and astrophotography.

Here’s a breakdown of the key features and potential:

Pros:

      • Excellent Optics: The Maksutov corrector lens minimizes spherical aberration and coma, resulting in pinpoint stars across the field. This translates to crisp, high-contrast views of planets, deep-sky objects, and even stunning wide-field shots.
      • No Diffraction Spikes: One of the reasons most astrophotographers choose refractors is due to the elimination of diffractions spikes.  Diffraction spikes occur with reflectors that have a spider vane holding the secondary mirror.  Most newtonians and SCTs have this issue.  You can see the spike on bright stars for all Hubble Telescope images due to this design.
    • This image was processed from three monochrome images using Siril and then edited in GIMP. The raw data is from the Hubble Space Telescope. Note the diffraction spikes around the bright images.
      • Versatile Performance: The design excels in both visual astronomy and astrophotography. Its wide field of view is a significant advantage for capturing large celestial objects.

Cons:

      • Heavy: The weight can be a challenge for some users, especially for extended observing sessions or for those with limited mobility.  You will need a heavy duty mount to handle the load.  The scope itself weighs 29lbs and will be more with cameras, guide scopes and other accessories.  For this reason, I bought a Skywatcher EQ6R-Pro which is large enough to handle this scope.
      • Collimation Sensitivity: While generally more stable than open Newtonians, the 190MN still requires occasional collimation checks, especially after transportation.

 

The Masksutov-Newtonian Design

The Maksutov-Newtonian telescope is a unique hybrid design that combines elements of two classic telescope types: the Maksutov and the Newtonian.1

Here’s a breakdown:

Maksutov Component:

      • At the front of the telescope, there’s a thick, meniscus-shaped lens.2 This lens, often made of glass, has a slight curve and corrects for spherical aberration, a common optical flaw in telescopes.3
      • The inner surface of this lens is typically curved to act as a secondary mirror, reflecting light back towards the primary mirror.

Newtonian Component:

      • The core of the telescope is a large, concave primary mirror at the base. This mirror reflects the incoming light back up the tube.
      • Instead of a traditional Newtonian diagonal mirror, the Maksutov-Newtonian uses the curved inner surface of the meniscus lens as a mounting point for the  secondary mirror. Since the meniscus is permanently mounted, no spider vanes are required to hold the secondary mirror.

How it Works:

      1. Light enters: Light from a celestial object enters the telescope through the meniscus lens.
      2. First Reflection: This lens corrects for some optical errors and then reflects the light towards the primary mirror.
      3. Second Reflection: The primary mirror reflects the light back up the tube to the secondary mirror.
      4. Focusing: The light is then focused by the combined action of the meniscus lens and the primary mirror, and finally reaches the eyepiece for viewing.

Key Advantages:

      • Sharp Images: The meniscus lens effectively corrects for spherical aberration, resulting in very sharp and clear images.

 

What You Get Out of The Box

The telescope is sold as an OTA and includes the following:

      • Telescope
      • 10 to 1 2″ Crayford focuser
      • 2 telescope rings
      • One dovetail bar
      • 9×50 right angle correct image finder scope

As with most Newtonian designs, the focuser does not have a camera angle adapter.  You will need to upgrade this yourself.  I’m going to buy the new ZWO CAA which was just released. 

The highly anticipated ZWO CAA allows for precise angle positioning of your image. It works seamlessly with the ASIAIR or other astrophotography applications.

Why I Chose To Buy It

Aperature matters.  The bigger the aperature, the higher the image resolution.  A higher resolution telescope allows you to see or photograph finer details.  The Maksutov Newtonian performs like an APO refractor, but it can do it for a fraction of the cost.  To get a refractor with a 7.5″ aperature, you would need to spend $7,000 to $10,000.  That’s a lot of money and I don’t recall winning the lottery lately.

On sale you might find this telescope for around $1,800 which is quite a deal compared to a similar refractor.

It’s Fast

Out of the box, this  is an F5.3 scope.  That’s pretty fast but not quite as fast as an F4 imaging newtonian.  My refractor I’m using now is an F7 but I added a focal reducer to bring it down to F5.7 which is a bit slower than the Sky-Watcher Mak Newtonian.

The faster the scope, the less time you need imaging.  Although a bit slower than the F4 Newtonians, this scope has pinpoint stars across the entire field and does not require a coma corrector or field flatner.  That’s a cool feature for sure.

1000 mm Focal Length

My current refractor with focal reducer is at 440mm which is wide field.  I’m often frustrated because I just don’t have enough reach for smaller galaxies and objects.  Therefore, I need a bit more magnification and 1000mm is just about perfect.

At 1000mm I can see Jupiter and Saturn but is still wide enough for a large number of galaxies and nebula. If I get a target that is just too large, I can switch to my refractor or create a mosaic with my new Mak Newtonian.

Overall:

The SkyWatcher 190MN is a high-performance telescope that offers a compelling blend of optical quality, portability, and versatility. If you’re seeking a telescope that excels in both visual and imaging applications, and are willing to invest in a premium option, the 190MN is definitely worth considering.

 

2023 Annular Eclipse

The Annular Solar Eclipse of 2023: A Spectacle of Light and Shadow

On October 14, 2023, an annular solar eclipse graced the skies of North, Central, and South America. This celestial event captured the attention of astronomers and skygazers alike, offering a glimpse into the intricate dance between the Sun, Moon, and Earth.

What is an annular solar eclipse?

An annular solar eclipse occurs when the Moon aligns perfectly between the Sun and Earth, but the Moon is too far away in its elliptical orbit to completely block the Sun’s light. This results in a dazzling ring of fire, where the Sun’s corona shines around the Moon’s silhouette.

Path of the 2023 eclipse

The path of the 2023 annular eclipse began in Oregon, USA, and swept across the continent, traversing through states like California, Nevada, Colorado, Texas, and Mexico. It then continued its journey over Central America and finally reached South America, culminating in Colombia.

The Visibility Feature in Stellarium Plus

The visibility feature in Stellarium Plus is a powerful tool that allows you to see which celestial objects will be visible at a given time and place. This information can be used to plan your observing sessions, or to simply learn more about the night sky.

The visibility feature is based on a number of factors, including your location, the date and time, the current sky conditions, and the brightness of the objects. You can use the visibility feature to see the following information for each object:

  • Highest altitude: The highest altitude that the object will reach above the horizon.
  • Setting and rising times: The times at which the object will set and rise.
  • Visibility time: The total amount of time that the object will be visible above the horizon.
The visibility features shows you now only the path of an object, but the time that it will be there.

The visibility feature is available in the Stellarium Plus app. To access it, simply click on the “Visibility” button in the toolbar. You can then use the controls in the visibility window to adjust the date and time, your location, and the sky conditions.

The visibility feature is a valuable tool for anyone who is interested in astronomy. It can be used to plan your observing sessions, to learn more about the night sky, or simply to see what objects will be visible at a given time and place.

Here are some additional tips for using the visibility feature:

  • Use the “Location” control to set your current location.
  • Use the “Date and Time” controls to set the date and time that you want to view.
  • Use the “Sky Conditions” controls to set the current sky conditions.
  • Use the “Filter” controls to filter the list of objects.

Note: Magnitude is a measure of the brightness of an object in the sky. The smaller the magnitude, the brighter the object. For example, the Sun has a magnitude of -26.74, while the faintest stars that can be seen with the naked eye have a magnitude of +6.0. The visibility feature in Stellarium Plus does not include magnitude, but it does include information about the brightness of objects.

How To Get The Visibility Feature

This feature is available only in Stellarium Plus.  You can download it on the Google Play store or for IOS. Note that for IOS, you can simply download the free version then upgrade to Plus right there in the app.

The cost is $20 on Google and as I recall about the same for IOS.

How To Stack Multiple Stacked Images With Siril

So how do you combine multiple imaging sessions with different calibration frames?  Well I had the same question and now I know how to do it with Siril.

Let’s say you have an imaging session on one night and then you shoot new flats the next night.  If you were to combine the raw image files and run the pre processing script now, you only have the choice to use one set of flats.

Fortunately there is a way to overcome this.  On any given night, you process the data using scripts and then you need to keep the pp_light files found in the processing folder.  All other data there can be deleted each night.

These pp_light files are already calibrated, so you can add more files on subsequent nights and then simply stack the stacked images.  Just add all the pp_lights to a sequence, register them and then do a sum stack and it’s done.

This is a great way to manage varying flat files (or darks for that matter) over multiple nights of imaging.

You can read this discussion here on Cloudy Nights

How To Install The ZWO EAF To The SVBONY 503 ED Telescope

I recently purchased the SVBONY 503 80ED telescope.  I love the dual focuser but I wanted to use the ZWO EAF with hand controller (Electronic auto focuser).  I’ll show you how to install it.

In general, the steps on how to install the ZWO EAF to an SBVONY 503 telescope are as follows:

  1. Gather your tools and materials. You will need the following:

    • ZWO EAF
    • SBVONY 503 telescope
    • Allen wrenches
    • Flexible coupling
    • M5 screws
    • Spacers
    • ZWO hand controller (optional)
    • ASIAIR (optional)
    • Other ASCOM software (optional)

  2. Remove the focus lock screw from the SBVONY 503 telescope.

  3. Remove the single-speed focuser knob from the SBVONY 503 telescope.

  4. Attach the flexible coupling to the focuser knob shaft.

  5. Attach the motor bracket to the focuser lock screw hole and tension hold screw hole.

  6. Insert the motor body onto the flexible coupling.

  7. Tighten the grub screws on the motor body.

  8. Align the motor body with the motor bracket.

  9. Attach the motor to the bracket with the M5 screws and spacers.

  10. Adjust the motor bracket so that it is just touching the motor body.

  11. Tighten the screw on the motor bracket.

  12. Test the EAF to make sure that it is working properly.

SVBony does have an install guide that you can check out here.

If you are using the ZWO hand controller, you can use it to control the EAF. If you are using ASIAIR or other ASCOM software, you can use that software to control the EAF. Now, I bought the hand controller because I do not want to bump the scope while focusing.  Each time I bump it, I am forced to wait a few seconds for the scope to settle down before taking the next test image.  This waists too much time and the hand controller solves this problem.  Given that it only adds $49 to the cost, I think it’s well worth the money.

The hand controller has 2 speeds which allow you to switch between fast but course corrections and then fine tune the result when you are close to focused.

SuperNova Remnants

A supernova is a powerful and luminous explosion of a star. It is the largest explosion that takes place in space. Supernovae are so bright that they can be seen from other galaxies. They are also the primary source of heavy elements in the universe.

Supernova Remnant W49B. Supernovas seed the universe with common elements such as oxygen and iron.

There are two main types of supernovae: core-collapse supernovae and Type Ia supernovae. Core-collapse supernovae occur when a massive star runs out of fuel and collapses in on itself. Type Ia supernovae occur when a white dwarf star explodes.

Core-collapse supernovae are the most common type of supernova. They occur when a star with more than eight times the mass of the Sun runs out of fuel. As the star collapses, it triggers a supernova explosion. The explosion releases a tremendous amount of energy, which can be seen from billions of light-years away.

Type Ia supernovae are less common than core-collapse supernovae, but they are much brighter. They occur when a white dwarf star explodes. A white dwarf star is a very dense star that is formed when a star runs out of fuel. If a white dwarf star is in a binary system with another star, it can steal matter from its companion star. If the white dwarf star accumulates too much matter, it will collapse in on itself and explode.

Supernovae are important because they are the primary source of heavy elements in the universe. Heavy elements are elements that are heavier than hydrogen and helium. They are essential for life as we know it. Supernovae also play a role in the evolution of galaxies. The energy from a supernova can trigger the formation of new stars.

Supernovae are a fascinating and important part of the universe. They are a reminder of the power of nature and the importance of stars.

Here are some interesting facts about supernovae:

  • Supernovae are one of the most powerful explosions in the universe.
  • A supernova can release more energy than the Sun will in its entire lifetime.
  • Supernovae are the primary source of heavy elements in the universe.
  • Heavy elements are essential for life as we know it.
  • Supernovae play a role in the evolution of galaxies.
  • The energy from a supernova can trigger the formation of new stars.
  • Supernovae are a fascinating and important part of the universe.

The Early Universe

Soon after the big bang, the universe was filled with mostly hydrogen and helium.  This gas condensed to form the first stars.  

Stars form when clouds of gas and dust collapse under their own gravity. These clouds, called nebulae, are found throughout the Milky Way galaxy and other galaxies.

The collapse of a nebula begins when a small region of the cloud becomes denser than the rest. This can happen due to a number of factors, such as turbulence or the presence of a nearby star. As the region collapses, it heats up due to compression. Eventually, the temperature and pressure at the center of the cloud become high enough to trigger nuclear fusion, and a star is born.

Stars emit light and heat from nuclear fusion.  As the star ages, new elements are formed as atoms are crushed together.

When certain types of stars die, they explode.  Not all stars end this way but the ones that do actually seed the universe with the heavier elements.  We are made of this which is literally star dust.

 

How To Collimate A Reflector Telescope

Reflector telescopes are made with 2 mirrors.  The main mirror is at the bottom and it’s bigger.  The smaller secondary mirror is in the middle of the telescope near the eyepiece.  Light from the main mirror is collected and concentrated onto the secondary mirror. The secondary mirror then directs this light to the eyepiece.

These two mirrors must be aligned properly or else the image quality will be reduced.  This process is called collimation.

Tools

To get the best alignment, I recommend a laser collimator.  These devices are cheap and pack a big bang for your buck.  You can precisely align your telescope without frustration.  They are also small enough that you can take it with you when you travel. 

You can also buy a small center spot to attach to the main mirror or do like I did and make a small mark with a permanent marker.  This small area will not affect the overall image since the secondary mirror blocks all light to the center of the main mirror. 

 

A laser collimator is the best way to collimate your telescope.

Orion LaserMate Deluxe II Laser Collimator – 05691

Check Price

Watch The Tutorial

The first step is to align the primary mirror so that it is pointing directly to the center of  the main mirror.

I put a small mark on the center of the main mirror.  You can use this method or you could place a small sticker there.  The point of the mark is to know exactly where the center is.  The first step is to place the laser collimator in the eyepiece and turn it on.  If the secondary mirror is correct, the laser will shine directly onto the center of the main mirror.  If this is not the case, then adjust the screws very slowly on the secondary mirror so that the laser lines up in the center.

Here the collimator laser shows proper alignment of the secondary mirror. You can see the laser is in the center of the primary mirror.

Once this step is complete, it’s time to align the primary mirror back up the secondary mirror.  The laser collimator can help you do this.

The return laser light is properly centered onto the target.

There is a small hole on the laser collimator where return light from the main mirror can enter.  You carefully adjust the main mirror screws so that the light from the laser goes through the small hole and centers itself onto the target.  Check out the video above to see exactly how I did this.  In that video I show how to collimate the Celestron 127EQ.  Note that in that video I have to remove the Bird Jones Lens.  Your telescope may not have this but keep that in mind.

RGB Processing Hubble Data In Siril

There is a great deal of incredible data that the Hubble Telescope has collected.  You can download it for free on the archive site.

To practice monochrome processing, you can try it yourself.  

Go to Hubble Legacy Archive and enter the site.

Search by name or catalog number.  In this example I’ll just type in Orion Nebula.  On the advanced search section, you can narrow your search.

I downloaded 3 files, one for Red, Green, and Blue.

Save these to your hardrive.

Open Siril.  Normally you will need to convert your images to fits file format.  Hubble data is already in fits so you can now go directly onto RGB Compositing.

Navigate to Image Processing ->RGB Compositing

To the right of the colors, click on the open button and select the correct fits monochrome color data for each color.

Once they are loaded, you can preview the image on the RGB color tab.

Star Alignment

You might notice that the stars are off since we did not register the images.  You an align them in Siril by drawing a box around a section of one of the colors, then selecting “and use this alignment method”.  Select “Image pattern alignment/Deep Sky”.  Press “Align”

Now the three channels should be aligned.  You can further edit the image or download a version.

Here is my first attempt at processing the Orion Nebula.  I was pleased with the level of detail in all three channels.

This image was processed from three monochrome images using Siril and then edited in GIMP. The raw data is from the Hubble Space Telescope

Telescope Filter Size Specification

Good summary of common astronomy threads.

Filter Connections

2″ filters use:

Male M48 x 0.75 thread

1.25″ filters use:

Male M28.5 x 0.6

T Connection

Male T/T2 thread (M42x0.75)

ZWO cameras

ZWO has standardized their connections. They use a T/T2 M42 x 0.75 thread. Therefore you can attach either a 1.25″ or 2″ nose adapter to the camera that uses a T/T2 male thread.

Eyepiece Filters

These filters fit on the back of the eyepiece.  For a 1.25″ filter, they commonly use an M28.5 x 0.6 thread.

1.25″ Filter Wheel

RGB Narrowband Image Processing With Siril

Basic Procedure

Take images in each band such as L, Red, Green, Blue or H-Alpha, O-III, or SII.  Collect Darks, Flats, Lights, and Biases one at a time.  Note that you will only need one master set of Darks and Biases since they are taken in the dark and are not dependent on the filter used.

Each color or narrow band should be in their own folder within the master directory for the project. These bands and individual channels will be stacked to form a master for each channel.

Open up Siril and process each color or narrow band one at a time using the monochrome script.  Save the image from each band in the master folder with good naming such as red_stacked, blue_stacked etc.

Combine Monochrome Images To Form A Color Image 

Now that each color or filter band is saved, the next step is to align the images.  This procedure is called Registration.

Add all of the channels in the Conversion tab and press “Convert”.  Next align the images with the Registration tab.  Do not stack.

Now go back to Image Processing->RGB Compositing.  Here you can assign R, G, B, L, or any narrow band image to combine into a single color image.  Select them from the list.  Note that the numbering order may be different than RGB.  It might be BGR so select accordingly.

A preview will now show and you can color correct at this point.  You can open one of the color tabs and select a dark area.  Draw a box around the dark area and choose “Use Current Selection”.  Then click “Background Neutralization”.  Now check the RGB tab and see if the preview better reflects the color you would expect.

Export Or Further Process

At this point you can save a Tiff of the linear version for further processing in Gimp or Photoshop.  You could also use Siril’s image processing if you choose.