
Celestron Omni XLT 150 Review: For many years, I photographed the night sky using tiny refractors. Refractors are excellent if properly adjusted, and they are reasonably priced up to 80mm in diameter. With a suitable reducer/flattener and a competent camera, it’s possible to generate lovely images: if tracking is done properly, stars will be pleasant and little pinpoints. Exposures of up to 2 minutes are achievable even without guiding using a medium-sized equatorial mount like the Celestron AVX. Polar alignment is critical, and I try to keep the focal length around 750mm.
Read This: Best telescope under $500
I’m often asked what the ideal entry-level scope is for seeing while simultaneously learning astrophotography. I would typically propose an 80mm ED or APO refractor with a motorized equatorial mount. There is no denying that they are very portable and provide quite pleasing results. There is, however, the question of light collecting. A big aperture is required to observe the fainter galaxies and nebulae. Even 4 inches is a tiny size. Well-corrected apochromatic refractors 5 inches and larger are costly and out of reach for the vast majority of people, especially novices.
This is where Newtonian design demands careful thought. I’ve spent the last year testing and working with Newtonian reflectors, and I’ve grown to like them. They are quick (the f-stop ratio allows for very short exposures), inexpensive, and extremely competent equipment for the moon, planets, and Deep Sky Objects. My first Newtonian was a huge 10′′ Dobsonian – the vistas were spectacular but other than some unforgettable moon shots, I couldn’t use it for imaging due to the simplistic mount. John Dobson, who dedicated his life to presenting astronomy to a wider audience, created this Newtonian to be as simple and affordable as possible, and there is simply no other telescope for visual observations that provides you more bang for your money.
Celestron Omni XLT 150 Review :Initial Results Using a Newtonian for Astrophotography
Last winter, I shot my first serious Deep Sky images with a Newtonian using a Vixen R200SS. What a fantastic scope! Using an 8-inch aperture and an F/4 ratio enabled me to dive deeper than I had ever gone before while still keeping my (unguided) exposures under one minute. Orion makes an 8-inch F/3.9 Newtonian astrograph that is less priced and performs quite well. They are just amazing all-around telescopes if you get acclimated to the inherent shortcomings of Newtonian design.
Celestron Omni XLT 150 Review: Newtonian Collimation
Consider the disadvantages for a minute. One of the most typical criticisms is that the mirrors must be consistently aligned (collimated) otherwise the views are subpar. True, but it’s not that complicated. There are several internet instructions that explain step by step how to use a Cheshire and/or laser collimator and most reflectors hold their collimation pretty well. Even the speedy Vixen R200SS requires just occasional re-alignment. It quickly becomes a habit that just takes a few minutes, therefore I suggest doing a short collimation before every picture session.
Celestron Omni XLT 150 Review: Eyepiece / Camera Position
The second disadvantage is the position of the eyepiece or camera: with a German Equatorial Mount (GEM), which is ideal for astrophotography, when you point the scope to a different location in the sky, the eyepiece suddenly ends up at the bottom (or top) of the tube and you need to loosen the tube rings and rotate the tube to see through it. One option is obtaining rotating parallax rings – fairly pricey, but they entirely remove the issue. My inexpensive method is to schedule most of my imaging in one region of the sky and then spend an additional few minutes loosening the rings and spin the tube when I go to another area of the sky. It’s also feasible to create your own “Wilcox” spinning rings, which perform well and keep the scope balanced.
Instructions for Making Your Own Wilcox Rotating Rings
Celestron Omni XLT 150 Review: Coma
The third disadvantage is visual, and it is particularly problematic with the faster Newtonians: coma. The coma appears near the frame’s boundaries (both optically and photographically) when stars become streaks rather than lovely pinpoints. A coma corrector is a universal remedy, and there are numerous decent ones available at reasonable prices. I propose the Baader MPCC (Multi Purpose Coma Corrector) as well as Roger Ceraglio’s GSO (or Astro Tech) Coma Corrector:Celestron Omni XLT 150 Review
When using this corrector with a DSLR (I use Nikons and Canons), a spacer ring is required to produce the right distance for the rear focus, as described lower down the post.
Celestron Omni XLT 150 Review: Tube Balance
The third problem that must be addressed is one of balance. The camera adds weight at the end of the tube with a refractor, which is easily compensated for by pushing the scope forward in its rings or the dovetail bar that links to the scope forward in its mount. With a reflector, the camera adds weight at the SIDE of the tube, generating a torque that will vary the balance of the tube dramatically depending on its location. The solution is to turn the tube such that the focuser is at the bottom of the tube, directly above the mount.
Of course, you won’t be able to do this if you wish to look through an eyepiece, but because your eyepiece weighs significantly less than the camera, it’s not an issue for visual observations.
: Celestron Omni XLT 150 ReviewDiffraction Spikes
Bright stars photographed with a Newtonian will often exhibit four diffraction spikes, which are caused by the spider vanes that keep the secondary mirror in place. It may be used as a creative effect – I like it for the Pleiades photograph. It is possible to purchase customized spiders with curved limbs to prevent the “star filter” appearance, but I don’t find it too bothersome.
Destiny Curved Vane Newtonian Spiders
Celestron Omni XLT 150 Review: Newtonian Advantages
Despite what may seem to be a huge list of additional issues to deal with, they are all small setbacks that may be quickly overcome. And the benefits are substantial: better light gathering, quicker f-stop ratios (shorter exposures, reduced tracking mistakes), and incredible sharpness and clarity for huge Newtonians. Some of the top lunar and planetary imagers choose a reflector over an apochromatic refractor that may cost three times as much – see, for example, Wes Higgins and his kids’ exceptional work:
High-Resolution Lunar and Planetary Photography by Wes Higgins
Celestron Omni XLT 150 Review: Beginner Newtonian for Astrophotography
One of the best beginner telescope kits available today is a 6-inch Newtonian on a motorized CG-4 equatorial mount. It is fully capable of basic astrophotography (moon, planets, and Deep Sky Objects), and the bigger aperture will reveal many more dim objects than an 80mm APO refractor. There is no artificial color on the moon or planets, and the photographs are quite crisp. Yes, you will require a coma corrector, and the mirrors will need to be collimated from time to time. You will have all you need to start this fantastic trip for about $750.
I suggested the Celestron Omni XLT 150 with a dual-axis motor drive to my close buddy Larry Bergl when he indicated a desire to learn more about the stars and purchase a fine telescope that would allow him to see as well as shoot Astro pictures. The mount, motors and gears, tripod, 6-inch Newtonian with finder, and one 25mm eyepiece are all included for a very affordable $560.
All you need is a polar alignment scope (around $40), the coma corrector, and some additional eyepieces: I’d start with some beautiful used Plossls in 5mm and 10mm focal lengths from Astromart or Cloudy Nights. Purchasing some carrying cases is also a good idea.
The scope came from High Point Scientific (great service; I would purchase from them again) in two enormous boxes, complete with instructions. The setup was simple and took less than thirty minutes (since I’ve done this many times before, it may take twice as long if this is your first time).
First light with the telescope under a semi-dark sky in the Santa Monica mountains (red zone, half an hour’s drive from my studio) was a lovely experience, particularly for Larry who was fully psyched about his new gadget. We observed a beautiful sunset before polar aligning the scope, which took around 10 minutes.
We were soon ready to go and see what the scope had to offer. The moon was a lovely crescent, only three days old. Jupiter was still fully visible in the west, while Mars and Saturn were brilliant and clear in the southern sky in the constellation Scorpius, near Antares.
The moon was stunning visually, with Mare Crisium sticking out like a black eye and the craters Peirce and Picard, as well as the minor crater Swift, plainly discernible. Jupiter’s equatorial belts and four Iovian moons were vividly visible; Saturn was razor crisp with a 5mm planetary eyepiece (150x magnification), and part of the Cassini divide was apparent in the outer rings (not in front of the planet). The mount was more than solid and tracked well, even if the slewing controls did not always react immediately: occasionally you had to push the keys for a few seconds before the scope began to move. However, our polar alignment must have been pretty excellent since generally a planet would linger in the center of the eyepiece for at least ten, to fifteen minutes.
After 45 minutes of observation, we were ready to test some shots to see what the scope and mount were capable of. We were certainly not disappointed here.
The Omni XLT 150 has a smooth 2-inch focuser that can comfortably accommodate a DSLR. Because only the center of the field can produce pinpoint stars without a coma corrector, the first step is to connect your camera to the coma corrector. If you use the GSO coma corrector described previously in the text (also available under the Astro Tech brand), detach the top section of the corrector that retains your eyepiece for visual usage. The bottom section, which houses the optics, includes T-threads at the top (M42 x 0.75mm) that will attach to your camera’s T-ring. This one is for the Canon EOS range.
Unfortunately, for the coma corrector to function successfully, the distance between the nearest lens element and the sensor of your camera must be around 75mm. Because your Canon EOS’s rear focus (FFD or Flange Focal Distance) is 44mm, you’ll need to buy additional T-thread spacers to make it work. This is the greatest value I found on eBay.
Because the T-ring adds at least another 10mm to the distance, I propose using the 15mm or 20mm spacer. The FFD on Nikons is 46.5mm, therefore the 20mm ring is probably the best option. Experiment with the spacers to find which ones produce the best pinpoint stars in the corners. I ended up utilizing two 10mm spacers I already had, which worked fine with the Canon EOS T2i.
Take note of how the camera’s focuser is pointed down, which is the optimum position for optimal balance. A well-balanced telescope is essential for excellent tracking: neither the declination nor the RA axis should be torqued. The scope must stay in its place with both clutches unlocked; if it is heavier on one side, adjust the counterweights or the location of the tube in the tube rings.
We began by capturing the crescent moon in single exposures with the prime focus. The ISO was set to 400, but since the scope is so quick, we could have easily used ISO 200. The exposures ranged from 1/100 to 1/200 seconds, with the best picture displaying a lot of detail at 1/160 second. Using a decent Barlow lens to expand the focal length would have been worthwhile; exposures would have been longer, but the picture would have been bigger. Longer exposures should be OK since the mount was tracking so nicely.
An interval timer must be linked to the camera for deep-sky photography. The CG-4 mount does not have an auto guider connection, although unguided exposures of up to 90 seconds are possible with this mount.
The Lagoon Nebula was our aim (Messier 8). We oriented the telescope towards the nebula after identifying it with some wide field 7 x 35 binoculars, and the image was rather magnificent despite being in the red zone with a 25mm eyepiece and a Lumicon deep sky filter. The Milky Way was obscured by light pollution, but the 6-inch mirror captured a significant number of dim stars and nebulosity.
Using the Canon EOS T2i’s live view, we focused on one of the brightest stars in the region. After achieving focus, the focuser may be locked down, which is critically required. Because of the delay with the slewing settings, it took 10 minutes of playing about with test exposures to get the nebula centered. When you’re accustomed to slicker, more costly GoTo mounts, it might be difficult to get things set up perfectly with a CG-4, but it still works!
Finally, we could begin the sequence of sub-exposures: twenty sub-exposures of 68 seconds each at ISO 1600. Eight of the twenty subs showed pinpoint stars, which were layered in Deep Sky Stacker with a dozen black frames. The end result is not awful for a low-cost telescope.
The low-cost Newtonian design is unquestionably capable of excellent astrophotography. It takes months, if not years, of shooting and processing expertise to get the most out of your camera, but the main line is that you may enjoy both visual and photographic work without spending a lot. We hope you have enjoyed this Celestron Omni XLT 150 Review.

Celestron Omni XLT 150 Review: For many years, I photographed the night sky using tiny refractors. Refractors are excellent if properly adjusted, and they are reasonably priced up to 80mm in diameter. With a suitable reducer/flattener and a competent camera, it’s possible to generate lovely images: if tracking is done properly, stars will be pleasant and little pinpoints. Exposures of up to 2 minutes are achievable even without guiding using a medium-sized equatorial mount like the Celestron AVX. Polar alignment is critical, and I try to keep the focal length around 750mm.
Read This: Best telescope under $500
I’m often asked what the ideal entry-level scope is for seeing while simultaneously learning astrophotography. I would typically propose an 80mm ED or APO refractor with a motorized equatorial mount. There is no denying that they are very portable and provide quite pleasing results. There is, however, the question of light collecting. A big aperture is required to observe the fainter galaxies and nebulae. Even 4 inches is a tiny size. Well-corrected apochromatic refractors 5 inches and larger are costly and out of reach for the vast majority of people, especially novices.
This is where Newtonian design demands careful thought. I’ve spent the last year testing and working with Newtonian reflectors, and I’ve grown to like them. They are quick (the f-stop ratio allows for very short exposures), inexpensive, and extremely competent equipment for the moon, planets, and Deep Sky Objects. My first Newtonian was a huge 10′′ Dobsonian – the vistas were spectacular but other than some unforgettable moon shots, I couldn’t use it for imaging due to the simplistic mount. John Dobson, who dedicated his life to presenting astronomy to a wider audience, created this Newtonian to be as simple and affordable as possible, and there is simply no other telescope for visual observations that provides you more bang for your money.
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ToggleCelestron Omni XLT 150 Review :Initial Results Using a Newtonian for Astrophotography
Last winter, I shot my first serious Deep Sky images with a Newtonian using a Vixen R200SS. What a fantastic scope! Using an 8-inch aperture and an F/4 ratio enabled me to dive deeper than I had ever gone before while still keeping my (unguided) exposures under one minute. Orion makes an 8-inch F/3.9 Newtonian astrograph that is less priced and performs quite well. They are just amazing all-around telescopes if you get acclimated to the inherent shortcomings of Newtonian design.
Celestron Omni XLT 150 Review: Newtonian Collimation
Consider the disadvantages for a minute. One of the most typical criticisms is that the mirrors must be consistently aligned (collimated) otherwise the views are subpar. True, but it’s not that complicated. There are several internet instructions that explain step by step how to use a Cheshire and/or laser collimator and most reflectors hold their collimation pretty well. Even the speedy Vixen R200SS requires just occasional re-alignment. It quickly becomes a habit that just takes a few minutes, therefore I suggest doing a short collimation before every picture session.
Celestron Omni XLT 150 Review: Eyepiece / Camera Position
The second disadvantage is the position of the eyepiece or camera: with a German Equatorial Mount (GEM), which is ideal for astrophotography, when you point the scope to a different location in the sky, the eyepiece suddenly ends up at the bottom (or top) of the tube and you need to loosen the tube rings and rotate the tube to see through it. One option is obtaining rotating parallax rings – fairly pricey, but they entirely remove the issue. My inexpensive method is to schedule most of my imaging in one region of the sky and then spend an additional few minutes loosening the rings and spin the tube when I go to another area of the sky. It’s also feasible to create your own “Wilcox” spinning rings, which perform well and keep the scope balanced.
Instructions for Making Your Own Wilcox Rotating Rings
Celestron Omni XLT 150 Review: Coma
The third disadvantage is visual, and it is particularly problematic with the faster Newtonians: coma. The coma appears near the frame’s boundaries (both optically and photographically) when stars become streaks rather than lovely pinpoints. A coma corrector is a universal remedy, and there are numerous decent ones available at reasonable prices. I propose the Baader MPCC (Multi Purpose Coma Corrector) as well as Roger Ceraglio’s GSO (or Astro Tech) Coma Corrector:Celestron Omni XLT 150 Review
When using this corrector with a DSLR (I use Nikons and Canons), a spacer ring is required to produce the right distance for the rear focus, as described lower down the post.
Celestron Omni XLT 150 Review: Tube Balance
The third problem that must be addressed is one of balance. The camera adds weight at the end of the tube with a refractor, which is easily compensated for by pushing the scope forward in its rings or the dovetail bar that links to the scope forward in its mount. With a reflector, the camera adds weight at the SIDE of the tube, generating a torque that will vary the balance of the tube dramatically depending on its location. The solution is to turn the tube such that the focuser is at the bottom of the tube, directly above the mount.
Of course, you won’t be able to do this if you wish to look through an eyepiece, but because your eyepiece weighs significantly less than the camera, it’s not an issue for visual observations.
: Celestron Omni XLT 150 ReviewDiffraction Spikes
Bright stars photographed with a Newtonian will often exhibit four diffraction spikes, which are caused by the spider vanes that keep the secondary mirror in place. It may be used as a creative effect – I like it for the Pleiades photograph. It is possible to purchase customized spiders with curved limbs to prevent the “star filter” appearance, but I don’t find it too bothersome.
Destiny Curved Vane Newtonian Spiders
Celestron Omni XLT 150 Review: Newtonian Advantages
Despite what may seem to be a huge list of additional issues to deal with, they are all small setbacks that may be quickly overcome. And the benefits are substantial: better light gathering, quicker f-stop ratios (shorter exposures, reduced tracking mistakes), and incredible sharpness and clarity for huge Newtonians. Some of the top lunar and planetary imagers choose a reflector over an apochromatic refractor that may cost three times as much – see, for example, Wes Higgins and his kids’ exceptional work:
High-Resolution Lunar and Planetary Photography by Wes Higgins
Celestron Omni XLT 150 Review: Beginner Newtonian for Astrophotography
One of the best beginner telescope kits available today is a 6-inch Newtonian on a motorized CG-4 equatorial mount. It is fully capable of basic astrophotography (moon, planets, and Deep Sky Objects), and the bigger aperture will reveal many more dim objects than an 80mm APO refractor. There is no artificial color on the moon or planets, and the photographs are quite crisp. Yes, you will require a coma corrector, and the mirrors will need to be collimated from time to time. You will have all you need to start this fantastic trip for about $750.
I suggested the Celestron Omni XLT 150 with a dual-axis motor drive to my close buddy Larry Bergl when he indicated a desire to learn more about the stars and purchase a fine telescope that would allow him to see as well as shoot Astro pictures. The mount, motors and gears, tripod, 6-inch Newtonian with finder, and one 25mm eyepiece are all included for a very affordable $560.
All you need is a polar alignment scope (around $40), the coma corrector, and some additional eyepieces: I’d start with some beautiful used Plossls in 5mm and 10mm focal lengths from Astromart or Cloudy Nights. Purchasing some carrying cases is also a good idea.
The scope came from High Point Scientific (great service; I would purchase from them again) in two enormous boxes, complete with instructions. The setup was simple and took less than thirty minutes (since I’ve done this many times before, it may take twice as long if this is your first time).
First light with the telescope under a semi-dark sky in the Santa Monica mountains (red zone, half an hour’s drive from my studio) was a lovely experience, particularly for Larry who was fully psyched about his new gadget. We observed a beautiful sunset before polar aligning the scope, which took around 10 minutes.
We were soon ready to go and see what the scope had to offer. The moon was a lovely crescent, only three days old. Jupiter was still fully visible in the west, while Mars and Saturn were brilliant and clear in the southern sky in the constellation Scorpius, near Antares.
The moon was stunning visually, with Mare Crisium sticking out like a black eye and the craters Peirce and Picard, as well as the minor crater Swift, plainly discernible. Jupiter’s equatorial belts and four Iovian moons were vividly visible; Saturn was razor crisp with a 5mm planetary eyepiece (150x magnification), and part of the Cassini divide was apparent in the outer rings (not in front of the planet). The mount was more than solid and tracked well, even if the slewing controls did not always react immediately: occasionally you had to push the keys for a few seconds before the scope began to move. However, our polar alignment must have been pretty excellent since generally a planet would linger in the center of the eyepiece for at least ten, to fifteen minutes.
After 45 minutes of observation, we were ready to test some shots to see what the scope and mount were capable of. We were certainly not disappointed here.
The Omni XLT 150 has a smooth 2-inch focuser that can comfortably accommodate a DSLR. Because only the center of the field can produce pinpoint stars without a coma corrector, the first step is to connect your camera to the coma corrector. If you use the GSO coma corrector described previously in the text (also available under the Astro Tech brand), detach the top section of the corrector that retains your eyepiece for visual usage. The bottom section, which houses the optics, includes T-threads at the top (M42 x 0.75mm) that will attach to your camera’s T-ring. This one is for the Canon EOS range.
Unfortunately, for the coma corrector to function successfully, the distance between the nearest lens element and the sensor of your camera must be around 75mm. Because your Canon EOS’s rear focus (FFD or Flange Focal Distance) is 44mm, you’ll need to buy additional T-thread spacers to make it work. This is the greatest value I found on eBay.
Because the T-ring adds at least another 10mm to the distance, I propose using the 15mm or 20mm spacer. The FFD on Nikons is 46.5mm, therefore the 20mm ring is probably the best option. Experiment with the spacers to find which ones produce the best pinpoint stars in the corners. I ended up utilizing two 10mm spacers I already had, which worked fine with the Canon EOS T2i.
Take note of how the camera’s focuser is pointed down, which is the optimum position for optimal balance. A well-balanced telescope is essential for excellent tracking: neither the declination nor the RA axis should be torqued. The scope must stay in its place with both clutches unlocked; if it is heavier on one side, adjust the counterweights or the location of the tube in the tube rings.
We began by capturing the crescent moon in single exposures with the prime focus. The ISO was set to 400, but since the scope is so quick, we could have easily used ISO 200. The exposures ranged from 1/100 to 1/200 seconds, with the best picture displaying a lot of detail at 1/160 second. Using a decent Barlow lens to expand the focal length would have been worthwhile; exposures would have been longer, but the picture would have been bigger. Longer exposures should be OK since the mount was tracking so nicely.
An interval timer must be linked to the camera for deep-sky photography. The CG-4 mount does not have an auto guider connection, although unguided exposures of up to 90 seconds are possible with this mount.
The Lagoon Nebula was our aim (Messier 8). We oriented the telescope towards the nebula after identifying it with some wide field 7 x 35 binoculars, and the image was rather magnificent despite being in the red zone with a 25mm eyepiece and a Lumicon deep sky filter. The Milky Way was obscured by light pollution, but the 6-inch mirror captured a significant number of dim stars and nebulosity.
Using the Canon EOS T2i’s live view, we focused on one of the brightest stars in the region. After achieving focus, the focuser may be locked down, which is critically required. Because of the delay with the slewing settings, it took 10 minutes of playing about with test exposures to get the nebula centered. When you’re accustomed to slicker, more costly GoTo mounts, it might be difficult to get things set up perfectly with a CG-4, but it still works!
Finally, we could begin the sequence of sub-exposures: twenty sub-exposures of 68 seconds each at ISO 1600. Eight of the twenty subs showed pinpoint stars, which were layered in Deep Sky Stacker with a dozen black frames. The end result is not awful for a low-cost telescope.
The low-cost Newtonian design is unquestionably capable of excellent astrophotography. It takes months, if not years, of shooting and processing expertise to get the most out of your camera, but the main line is that you may enjoy both visual and photographic work without spending a lot. We hope you have enjoyed this Celestron Omni XLT 150 Review.