I did some stargazing tonight after a long time. Throughout the summer, it has been cloudy and hazy. However, tonight was a clear sky with little haze. I took my 120mm diameter 1000mm focal length reflector telescope out to my office terrace, as it has the best view. I have a single plossal zoom eyepiece that I use for all my stargazing. It is a Seben zoom eyepiece, 7.5-22.5mm focal length.
I started out by aligning my finder scope to the optical tube. This is a very important step as it is quite difficult to find any celestial object without using a finder scope. To align the finder scope, I first locate the moon and get it in the telescope's field of view. This is much easier than locating point sources such as stars. I then adjust the alignment screws on the finderscope to bring the moon to the centre of the finderscope's field of view. Alignment complete.
Tonight, the moon was a beautiful waxing cresent (always reminds me of Cheshire the cat). The interface between the bright and the dark part of the moon, known as the terminator, exaggerates all relief features on the moon's surface by casting long shadows. To a person standing near the terminator on the moon, it would be sunrise or sunset. Craters, hills and cliffs look best near the terminator and make you feel like your telescope has very high resolution. It's always a delight to look at moon's craters with high magnification. I start off with 22.5 mm, centre the moon in the field of view and then zoom to the desired level. When you zoom using the seben eyepiece, you have to adjust the focuser to bring the image to a sharp focus.
Next I looked at Venus. Venus is the second brightest object in the night sky and is thus easy to spot. However, it is too bright to be viewed directly. It only appears as a very bright white disk/oval like shape. Venus is currently in the Gemini constellation. Tonight the Venus was in half phase and thus appeared as an oval. Even after zooming to 133x Venus was too bright and I could not spot any details. Next time I will use a filter to reduce the brightness when viewing Venus.
Next I observed Jupiter and its moons. Jupiter is currently is between Leo and Gemini. Jupiter is fun to observe and even with an average telescope, you can see 2 bands on jupiter and four of its moons (Io, Europa, Ganymede and Callisto). These four moons usually appear in-line because of their plane of orbit. Tonight all four were on the same side, with Io nearly on top of Jupiter. Sometimes, you can see the shadow cast by one of jupiter's moons on its surface! I could see 3 more very faint moons, but sometimes its hard to say whether I imagined it or if it was really there.
I then looked at Saturn, near the Scorpio constellation. Saturn is probably the best planet to look at. Its rings are very clear and about 4-5 times its diameter. It appears yellowish in colour. With my telescope I could see 2 of Saturn's moons. One directly in line with its rings and one perpendicular to them. Cassini's division is hard to see, but as conditions were favourable tonight I was able to see it. At high magnifications, it is hard to focus saturn as it appears blurry anyway. Also, my Seben eyepiece shows plenty of chromatic aberrations as I increase the zoom.
I spent quite some time looking for M4 globular cluster, near Scorpio. Usually it is easy to find, but since Scorpio's altitude was very low, I could not locate it.
Finally I looked at M5 globular cluster, in the Serpens constellation. Star clusters are fun to spot as they present a challenge. Light pollution in cities combined with the diffused glow of star clusters force you to use averted vision to observe them. The retina has lower concentration of rod cells(light sensing) at its center point(fovea) as compared to the surrounding region. Thus when you directly stare at a very dim object, you may not spot it, whereas staring somewhere near the dim object, suddenly brings it to light. However, this technique makes looking for dim objects very hard. But, M5 is a relatively easy star cluster to spot as it has a moderately bright star very close to it. So once you spot the star, you see the cluster using averted vision. Through my telescope, M5 appears as a greyish haze. It actually comprises of thousands of very faint stars concentrated in a small region. Thus, it is not very appealing visually, but it is very photogenic.
My viewing session was around 1.5 hours long. When I'm done I close the optical tube with my solar filter, to prevent dust settling on the mirrors.
Goto and tracking function will help me not only view but also take pictures of these celestial objects. I'm hoping to finish upgrading my goto mount in time before monsoon sets in.
Until next time,
Clear skies!
I started out by aligning my finder scope to the optical tube. This is a very important step as it is quite difficult to find any celestial object without using a finder scope. To align the finder scope, I first locate the moon and get it in the telescope's field of view. This is much easier than locating point sources such as stars. I then adjust the alignment screws on the finderscope to bring the moon to the centre of the finderscope's field of view. Alignment complete.
Tonight, the moon was a beautiful waxing cresent (always reminds me of Cheshire the cat). The interface between the bright and the dark part of the moon, known as the terminator, exaggerates all relief features on the moon's surface by casting long shadows. To a person standing near the terminator on the moon, it would be sunrise or sunset. Craters, hills and cliffs look best near the terminator and make you feel like your telescope has very high resolution. It's always a delight to look at moon's craters with high magnification. I start off with 22.5 mm, centre the moon in the field of view and then zoom to the desired level. When you zoom using the seben eyepiece, you have to adjust the focuser to bring the image to a sharp focus.
Next I looked at Venus. Venus is the second brightest object in the night sky and is thus easy to spot. However, it is too bright to be viewed directly. It only appears as a very bright white disk/oval like shape. Venus is currently in the Gemini constellation. Tonight the Venus was in half phase and thus appeared as an oval. Even after zooming to 133x Venus was too bright and I could not spot any details. Next time I will use a filter to reduce the brightness when viewing Venus.
Next I observed Jupiter and its moons. Jupiter is currently is between Leo and Gemini. Jupiter is fun to observe and even with an average telescope, you can see 2 bands on jupiter and four of its moons (Io, Europa, Ganymede and Callisto). These four moons usually appear in-line because of their plane of orbit. Tonight all four were on the same side, with Io nearly on top of Jupiter. Sometimes, you can see the shadow cast by one of jupiter's moons on its surface! I could see 3 more very faint moons, but sometimes its hard to say whether I imagined it or if it was really there.
I then looked at Saturn, near the Scorpio constellation. Saturn is probably the best planet to look at. Its rings are very clear and about 4-5 times its diameter. It appears yellowish in colour. With my telescope I could see 2 of Saturn's moons. One directly in line with its rings and one perpendicular to them. Cassini's division is hard to see, but as conditions were favourable tonight I was able to see it. At high magnifications, it is hard to focus saturn as it appears blurry anyway. Also, my Seben eyepiece shows plenty of chromatic aberrations as I increase the zoom.
I spent quite some time looking for M4 globular cluster, near Scorpio. Usually it is easy to find, but since Scorpio's altitude was very low, I could not locate it.
Finally I looked at M5 globular cluster, in the Serpens constellation. Star clusters are fun to spot as they present a challenge. Light pollution in cities combined with the diffused glow of star clusters force you to use averted vision to observe them. The retina has lower concentration of rod cells(light sensing) at its center point(fovea) as compared to the surrounding region. Thus when you directly stare at a very dim object, you may not spot it, whereas staring somewhere near the dim object, suddenly brings it to light. However, this technique makes looking for dim objects very hard. But, M5 is a relatively easy star cluster to spot as it has a moderately bright star very close to it. So once you spot the star, you see the cluster using averted vision. Through my telescope, M5 appears as a greyish haze. It actually comprises of thousands of very faint stars concentrated in a small region. Thus, it is not very appealing visually, but it is very photogenic.
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| professional pic of M5 globular cluster |
Goto and tracking function will help me not only view but also take pictures of these celestial objects. I'm hoping to finish upgrading my goto mount in time before monsoon sets in.
Until next time,
Clear skies!
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