The moon.....CP995 + Meade DS-80 Telescope

roygoh · 16th November 2002

A bit late in joining the moon photography league...here's a full-frame shot of the moon I took last night:

Finally received my William Optics DCL-28 eyepiece yesterday, and the weather last night was suddenly clear after a week of non-stop raining (almost).

The DCL-28 is specifically designed for digicams with 28mm thread. It can be attached to the camera directly like a filter, which then allows you to attach your camera to any telescope with a 1.25 inch eyepiece holder.

With the eyepiece, I attached my CP995 to a Meade DS-80 telescope. The telescope and the DCL-28 provided a magnification of 37.5x. The camera zoom was set at 15.5mm (~70mm on 35mm format equivalent). So the equivalent focal length is 37.5 x 70 = 2625mm. ISO 100, 1/250 sec, f/3.4(on camera).

Pre-focused with telescope until image is acceptably clear on the camera LCD, and then activate 3-sec self timer for the shot.

Took a total of about 20 shots, and this is the best I can find.

On PS, I removed the red and blue channels, converted the green channel to greyscale, adjusted levels and curves, and then USM and resize. When I looked at the 3 channels separately, the blue channel is the most noisy and un-focused. Red is slightly better but green is the best.

Comments are welcomed.

Thanks!

Roy

denizenx · 16th November 2002

Arl arl arwooooooooool!

oops me no wolfgang!

roygoh · 16th November 2002

Quote:

Originally posted by denizenx
Arl arl arwooooooooool!

oops me no wolfgang!

I thought that only happens during a full moon?

denizenx · 16th November 2002

yeah lor... usually only do it at sentosa beaches... LOL

denizenx · 16th November 2002

lots of full moons there...

denizenx · 16th November 2002

come to think of it shd be partial moons... else I'd die from nosebleed liao...

roygoh · 16th November 2002

Quote:

Originally posted by denizenx
lots of full moons there...

huh?

denizenx · 16th November 2002

no wonder I baying here... LOL

oh yeah the token Nice Shot!

so big and moony

last night I was having weird sky... my top 30deg of sky had stars and satellites, but in front of me was a 130deg wide stretch of storm clouds with constant static discharge...
shot 3 shots of 2 min, 4 min, x min... hope comes out nice...
used an All Blacks cap to do the manual shutter.. hee

denizenx · 16th November 2002

Quote:

Originally posted by roygoh

huh?

go to mahalo on a saturday... u'd know what I mean

Wai · 16th November 2002

well done...next will be saturn?

roygoh · 16th November 2002

Quote:

Originally posted by Wai
well done...next will be saturn?

Thanks!

Saturn? Let's hope there is enough clear nights here in Seattle for me to practise locating the planet first. According to the Autostar manual, I am supposed to be able to select any planets on the keypad and the controller will bring the telescope to point at it automatically.

Not sue if there is enought magnification and aperture on the telescope though...

Wai · 16th November 2002

so good...the moon should looks bigger in Seattle than in Singapore rite?

Ian · 16th November 2002

Roy,

Nicely done for a gibbeous moon.

megaweb · 16th November 2002

Awesome

roygoh · 16th November 2002

Quote:

Originally posted by Wai
so good...the moon should looks bigger in Seattle than in Singapore rite?

Yeah, the moon does seem bigger here than in Singapore. Not sure if I am imagining this or if there is some scientific explanation.

Ian can help? Has it got anything to do with the difference in distance from the moon for these 2 places? I don't think that should be significant, though.

roygoh · 16th November 2002

Quote:

Originally posted by Ian
Roy,

Nicely done for a gibbeous moon.

Thanks, Ian.

Hope you can give some advice. Since the moon is white, I could get away with discarding the red and blue channels and end up with a much better image. Is the lousy blue and red channels a result of chormatic abberation caused by the telescope and eyepiece?

If I photograph the moon on B&W film, is it then a common practise to apply some sort of narrow band filter to achieve the best possible focus?

Thanks!

- Roy

roygoh · 16th November 2002

Quote:

Originally posted by denizenx
used an All Blacks cap to do the manual shutter.. hee

Read about that technique. It can be used to minimize or eliminate camera shake at the beginning and end of a long exposure caused by the movement of the mirror and shutter.

SniperD · 16th November 2002

wah say... even the crators are clearly seen!!!

Ian · 16th November 2002

Quote:

Originally posted by roygoh

Thanks, Ian.

Hope you can give some advice. Since the moon is white, I could get away with discarding the red and blue channels and end up with a much better image. Is the lousy blue and red channels a result of chormatic abberation caused by the telescope and eyepiece?

If I photograph the moon on B&W film, is it then a common practise to apply some sort of narrow band filter to achieve the best possible focus?

Thanks!

- Roy

Roy,

Achromatic type refractors often have slight residual chromatic abberations

Without running a couple of star tests I can't say if it's the camera or scope that's producing the chromatic abberations, or the occular for that matter. One way to get a good idea is to focus on a bright white star such as Sirius or Canopus and then move the image in and out of focus. Any chromatic abberation will show up as fringent colour rings. You can also do this on the very edge of the moon. Change eyepieces and see what happens as well.

With b/w film there's no narrow pass filters that will increase focusing accuracy.(apart from the usual ones like light pollution bandpass filters which may or may not improve the image. The best low tech method to improve focus on the moon is to use a Hartman mask focusing aid.

A couple of general points to remember.

Turbulence in the atmosphere causes the moon to 'shimmer' and the rate of this shimmer is determined by the size and steadyness of the warm and cool air columns. The oscillation of these air columns acts like a damn big lens that swings the moon in and out of focus (and most other objects).

If you observe the moon for 10-15 minutes you'll pick periods where the seeing is 'steady' those are the times u take a shot.

The moon is essentially the same real diameter anywhere on Earth. A difference of a couple of thousand KM over a distance of 300,000 KM makes no appreciable difference to it's actual angular diameter. This leads us to wonder why the moon looks bigger at northern or southern latitudes and the answer is ... atmospheric refraction.

denizenx · 16th November 2002

Quote:

Originally posted by roygoh

Yeah, the moon does seem bigger here than in Singapore. Not sure if I am imagining this or if there is some scientific explanation.

LOL the moon abroad is always rounder huh?

16th November 2002	#1
roygoh Moderator Join Date: Jan 2002 Location: Northwest Posts: 5,042	The moon.....CP995 + Meade DS-80 Telescope A bit late in joining the moon photography league...here's a full-frame shot of the moon I took last night: Finally received my William Optics DCL-28 eyepiece yesterday, and the weather last night was suddenly clear after a week of non-stop raining (almost). The DCL-28 is specifically designed for digicams with 28mm thread. It can be attached to the camera directly like a filter, which then allows you to attach your camera to any telescope with a 1.25 inch eyepiece holder. With the eyepiece, I attached my CP995 to a Meade DS-80 telescope. The telescope and the DCL-28 provided a magnification of 37.5x. The camera zoom was set at 15.5mm (~70mm on 35mm format equivalent). So the equivalent focal length is 37.5 x 70 = 2625mm. ISO 100, 1/250 sec, f/3.4(on camera). Pre-focused with telescope until image is acceptably clear on the camera LCD, and then activate 3-sec self timer for the shot. Took a total of about 20 shots, and this is the best I can find. On PS, I removed the red and blue channels, converted the green channel to greyscale, adjusted levels and curves, and then USM and resize. When I looked at the 3 channels separately, the blue channel is the most noisy and un-focused. Red is slightly better but green is the best. Comments are welcomed. Thanks! Roy __________________ As complexity rises, precise statements lose meaning and meaningful statements lose precision.

16th November 2002	#2
denizenx Senior Member Join Date: Feb 2002 Location: L2TPYSG Posts: 4,514	Arl arl arwooooooooool! oops me no wolfgang! __________________ "I'm... dreaming... of a wide... angle~ Just like the ones I used to know~"

16th November 2002	#4
denizenx Senior Member Join Date: Feb 2002 Location: L2TPYSG Posts: 4,514	yeah lor... usually only do it at sentosa beaches... LOL __________________ "I'm... dreaming... of a wide... angle~ Just like the ones I used to know~"

16th November 2002	#5
denizenx Senior Member Join Date: Feb 2002 Location: L2TPYSG Posts: 4,514	lots of full moons there... __________________ "I'm... dreaming... of a wide... angle~ Just like the ones I used to know~"

16th November 2002	#6
denizenx Senior Member Join Date: Feb 2002 Location: L2TPYSG Posts: 4,514	come to think of it shd be partial moons... else I'd die from nosebleed liao... __________________ "I'm... dreaming... of a wide... angle~ Just like the ones I used to know~"

16th November 2002	#10
Wai Senior Member Join Date: Jan 2002 Location: South Pole with Penguins Posts: 5,129	well done...next will be saturn? __________________ We are HDD of PC & FT are MB add to storage; so PC never hangs with enormous storage capacity - LKY

16th November 2002	#13
Ian Senior Member Join Date: Feb 2002 Location: Perth Australia Posts: 2,321	Roy, Nicely done for a gibbeous moon. __________________ The Ang Moh from Hell

16th November 2002	#14
megaweb Moderator Join Date: Jan 2002 Location: East Posts: 8,106	Awesome __________________ See my Photo Gallery at the Clubsnap \| Pbase

16th November 2002	#18
SniperD Senior Member Join Date: Oct 2002 Location: Behind the viewfinder... Posts: 5,954	wah say... even the crators are clearly seen!!! __________________ EYE-DEAS