7 January 2011

Filters

I have seen several listings of filters and what they are good for and the ones I have seen so far have always been arranged by filter color which seems bass ackwards to me. It is like the people who write these lists are saying

“Gee, I have this red filter. What can I look at with it?”

I approach filters from the other side of the coin saying

“I am not seeing as much detail in Jupiter as the space telescope pictures tell me is there. Do I have a filter that will alter the view to let me see more?”

So I have been collecting filter data and have organized it by object so it is easier for me to use.

Sources: Celestron; Astronomy Hacks

Sun
Wratten	Color	Use
#21	Orange	With a Mylar filter, adding the orange filter will return the Sun to its “true” color

Moon
Wratten	Color	Use
#8	Light Yellow	Improves contrast Better appearance of features
#12	Yellow	Improves contrast Better appearance of features
#15	Deep Yellow	Enhances features
#21	Orange	Greatly enhances features
#25	Red	Improves features
#47	Violet	Improves detail
#56	Light Green	Enhances features
#58	Green	Enhances features
#82A	Pale Blue	Brings out low contrast features
#80A	Blue	Enhances detail
Moon	Neutral Density	Reduces brightness making it more comfortable to view the Moon Improves contrast Brings out detail Clear aperture is 21mm, ~84% of normal; 18% transmission

Mercury
Wratten	Color	Use
#21	Orange	Reduces brightness of sky during daytime/twilight Brigs out surface features
#25	Red	Improves observation in twilight when the planet is near the horizon During daylingt, reduces brightness of sky Brings out surface eatures
#29	Deep Red	Improves sky contrast during daytime and twilight Brings out surface features
#47	Violet	Observing clouds Improves contrast Brings out features
#80A	Blue	Improves dusky surface markings at twilight when the planet is near the horizon

Venus
Wratten	Color	Use
#11	Yellow-Green	Observing clouds
#15	Deep Yellow	Reveal low-contrast surface features Observe Clouds Observe ice caps
#21	Orange	Reduces sky brightness during daytime observing
#25	Red	Reduces brightness of daytime sky Terminator deformations
#29	Deep Red	Inproves daytime and twilight sky contrast Observe clouds Increases Contrast Brings out surface detail
#47	Violet	Observe clouds Improve contrast Brings out detail Favorite Venus filter for many observers
#56	Light Green	Observing clouds Reduces daytime sky brightness
#58	Green	Observing clouds Reduces daytime sky brightness
#80A	Blue	Increases contrast of dark shadings in upper clouds
#38A	Deep Blue	Observe clouds

Mars
Wratten	Color	Use
#8	Light Yellow	Observe maria
#11	Yellow-Green	Observe maria Observe ice caps
#12	Yellow	Observe maria
#15	Deep Yellow	Reduce light from blue and green areas which darkens the maria, oases and canal markings, while lightening the orange-hued desert regions Sharpens boundaries of yellow dust clouds Increases contrast
#21	Orange	Reduce light from blue and green areas which darkens the maria, oases and canal markings, while lightening the orange-hued desert regions Sharpens boundaries of yellow dust clouds
#25	Red	Observe polar ice caps Observe surface features sharpens boundaries of yellow dust clouds
#29	Deep Red	Observe Maria Observe ice caps Observe surface detail
#47	Violet	Observe ice caps
#56	Light Green	Observe dust storms observe ice caps Observe dust storms
#58	Green	Excellent to increase contrast of polar ice caps, low clouds and yellowish dust storms
#82A	Pale Blue	Brings out low-contrast features Improves detail
#80A	Blue	Observe dust storms
#38A	Deep Blue	Observe dust storms

Jupiter
Wratten	Color	Use
#8	Light Yellow	Observe belts
#11	Yellow-Green	Observe clouds Improves feature contrast
#12	Yellow	Observe belts
#15	Deep Yellow	Penetrate and darken atmospheric currents containing low-hue blue tones Enhance orange and red features of the belts and zones Useful for polar cap studies Increases contrast
#21	Orange	Improves appearance of detail revealed in structure of belts Enhances festoons Enhances polar regions
#25	Red	Used to study bluer clouds Observe belts Observe transits
#29	Deep Red	Observe clouds Observe belts Observe transits
#56	Light Green	Observe Clouds Increase low-contrast detail
#58	Green	Observe clouds Reduces sky brightness during daytime
#82A	Pale Blue	Observe low-contrast features Increase observed detail
#80A	Blue	Enhance boundaries between the reddish belts and adjacent bright zones Observe Great Red Spot
#38A	Deep Blue	Observe belts Observe Great Red Spot

Saturn
Wratten	Color	Use
#8	Light Yellow	Observe belts
#11	Yellow-Green	Observe the Cassini Division
#12	Yellow	Observe belts
#15	Deep Yellow	Increases contrast
#21	Orange	Improves band structure Highlights blue polar regions
#25	Red	Observe bluer clouds
#29	Deep Red	Observe clouds
#47	Violet	Observe ring structure
#56	Light Green	Observe clouds Observe surface detail
#58	Green	Observe clouds Observe belts Observe polar regions
#82A	Pale Blue	Observe low-contrast features Increases observed detail Observe cloud belts
#80A	Blue	Penetrate and darken atmospheric currents containing low-hue blue tones Enhance orange and red features of belts and zones
#38A	Deep Blue	Observe rings Observe belts Observe clouds

Uranus
Wratten	Color	Use
#8	Light Yellow	Increases observed detail
#11	Yellow-Green	Increases contrast Increases observed detail
#12	Yellow	Increases observed detail
#15	Deep Yellow	Improve detail in larger telescopes (>10”)

Neptune
Wratten	Color	Use
#8	Light Yellow	Increase observed detail
#11	Yellow-Green	Increase contrast Increase observed detail
#12	Yellow	Increase observed detail
#15	Deep Yellow	Improve detail in larger telescopes (>10”)

Comets
Wratten	Color	Use
#8	Light Yellow	Increases observed detail
#15	Deep Yellow	Enhances tail definition
#21	Orange	Enhances definition in dust trails and heads in larger telescopes (>10”)
#58	Green	Useful for observing brighter comets
#82A	Pale Blue	Observe comet tails
#80A	Blue	Best definition in gast tails
#38A	Deep Blue	Bright comet tails

Galaxies
Wratten	Color	Use
#82A	Pale Blue	Observe detail in bright galaxies

5 December 2010

5 November 2010

7 October 2010

8 September 2010

1 September 2010

14 August 2010

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Observing Location	TotL
Observational Period	2100-0100 EDT
Atmospheric Conditions	Cloud Cover Clear to Scattered Cloud Temperature ° F Wind Wind Chill Effect Heat Index ° F Humidity Barometric Pressure " Hg KNYC METAR Feels Like Cool Transparency Fair Seeing II
Instruments	Celestron Outland 8x42 binocular- Charlie Takahashi 22x60 binocular - Peter Nikon 8x42 binocular - Veshakha
Observing Party	Charlie Ridgway Peter Tagatac Veshakha Apte

I entered The Great Lawn from the Delacort Theater path and walked counterclockwise around the Lawn to try to see if I could see any of the planets. Venus was at about 7° elevation at that time and I think we have previously determined that out local horizon is around 5° so at least Venus should have been visible. I can't tell if there were clouds in the way or if it was behind a building or tree but it doesn't much matter as no planets were visible.

Target M7, Ptolemy's Cluster, NGC 6475 Constellation Sco Category DSO: OC Time yyyymmdd.hhmm 20100814.2155 EDT Luminosity 2,616 Sols Magnitude 3.3 Surface Brightness 12/sq' Size 75x75' 18x18 ly Shape Circular Difficulty 6 Distance 820 ly Age 298.5 my Location Where is M13 graphicSky Voyager graphic References Deep Sky Observer’s Guide: 127, 171, 175 Stars and Planets: Binocular Highlights: The Observer’s Sky Atlas: Comments A large loose open cluster. I see three levels of brightness. It looks like an airplane with stubby wings

Target M6, Butterfly Cluster, NGC 6405 Constellation Sco Category DSO: OC Time yyyymmdd.hhmm 20100814.2234 EDT Luminosity 3,822 Sols Magnitude 4.2 Surface Brightness 10/sq' Size 25x25 11x11 ly' Shape Circular Difficulty 6 Distance 1,500 ly Age 94.2 my Location Where is M13 graphicSky Voyager graphic References Deep Sky Observer’s Guide: 126-127 Stars and Planets: 319 Celestial Sights, Celestial Splendors: 319 Binocular Highlights: The Observer’s Sky Atlas: E18 Comments Easily seen. No notes on what it looked like.

Target Mizar & Alcor Constellation UMa Category Double Star Time yyyymmdd.hhmm 20100814.2240 EDT Comments Alcor was not seen naked-eye.

Target M13, Herculese Cluster, NGC 6205 Constellation Her Category DSO: GC Time yyyymmdd.hhmm 20100814.2245 EDT Luminosity 223,583 Sols Magnitude 5.9 Surface Brightness 12/sq' Size 20x20' 146x146 ly Shape Circular Difficulty 5 Distance 25,100 ly Location Where is M13 graphicSky Voyager graphic References Deep Sky Observer’s Guide: 44, 47, 78, 79-80, 81, 82, 176 Stars and Planets: 31, 32, 159, 190, 192, 260 Celestial Sights, Celestial Splendors 96-97 Binocular Highlights: 55 The Observer’s Sky Atlas: N14 Comments Faint and fuzzy. Makes a very shallow triangle with the adjacent stars.

Target M92 Constellation Her Category DSO: GC Time yyyymmdd.hhmm 20100814.2255 EDT Luminosity 145,584 Sols Magnitude 6.5 Surface Brightness 11/sq' Size 14x14' 109x109 ly Shape Circular Difficulty 5 Distance 26,700 ly Location Where is M13 graphicStar Voyager graphic References Deep Sky Observer’s Guide: 80, 81 Stars and Planets: 190, 260 Cekestial Sights, Celestial Splendors: 108-109 Binocular Highlights: The Observer’s Sky Atlas: N14 Comments Appeared as a defocused spot a little smaller than a pea. I didn't see the stars that Peter and V saw. It was hard to get in the exit pupil of the binocular with my glasses when it was pointed that high in the sky.

Target M11, Wild Duck Cluster, NGC 6705, Cr 391 Constellation Sct Category DSO: OC Time yyyymmdd.hhmm 20100814.2335 EDT Luminosity 14,958 Sols Magnitude 5.8 Surface Brightness 11/sq' Size 11x11' 20x20 ly Shape Circular Difficulty 5 Distance 6,200 ly Age 200.4 my Location Where is M13 graphicStar Voyager graphic References Deep Sky Observer’s Guide: 91, 110, 113, 114, 128, 176 Stars and Planets: 162, 190, 296 Celestial Siights, Celestial Splendors 40-41 Binocular Highlights: 66 The Observer’s Sky Atlas: E19 Comments A nondescript faint patch of sky adjacent to a bright star.

Target M26, NGC 6853, Cr 389 Constellation Sct Category DSO: OC Time yyyymmdd.hhmm 20100814.2355 EDT 48-49 Binocular Highlights: The Observer’s Sky Atlas: E19 Luminosity 1,387 Sols Magnitude 8.0 Surface Brightness 12/sq' Size 10x10' 15x15 ly Shape Circular Difficulty 3 Distance 5,200 ly Age 85.3 my Location Where is M13 graphicStar Voyager graphic References Deep Sky Observer’s Guide: 128 Stars and Planets: 296 Celestial Sights, Celestial Splendors: Comments Not Seen This one wasn't seen by anyone although we were right on it. It didn't even make it into my notes

Target Jupiter Constellation Vir Category Planet Time yyyymmdd.hhmm 20100815.0015 EDT       Object Class Classical Planet Elongation ° Distance Light Time (from Earth) AU m s Distance (from Sun) AU Angular Size "x" Magnitude - Central Meridian I/II °/° Altitude ° Sky Voyager graphic Comments I could see three moons out on one sie of the planet and one on the other side. The NEB was not visible at all and the SEB did not stretch to the edges of the disc.

M31, Andromeda Galaxy, NGC 224 Target Constellation And Category DSO: Gal,Sb Time yyyymmdd.hhmm 20100815.0020 EDT Luminosity 5,600,000,000 Sols Magnitude 4.8 Surface Brightness 13/sq' Size 178x63' 12,412x43,980 ly Shape Ellipse Difficulty [6] Distance 240,000 ly Location Where is M13 graphicStar Voyager graphic References Deep Sky Observer’s Guide: 11, 16, 18, 42, 47, 49, 50, 53-55, 74, 75, 77, 146 Stars and Planets: 30, 40, 171, 172, 190, 193, 244 Celestial Sights, Celestial Splendors: 148-149 Binocular Highlights: 88, 89 The Observer’s Sky Atlas: E22 Comments Saw it in my own hand-held binocular. I wasn't steady enough to describe what I saw. Light clouds were passing in front of it but you could see it through them.

Target Uranus Constellation Vir Category Planet Time yyyymmdd.hhmm 20100815.2030 EDT       Object Class Classical Planet Elongation ° Distance Light Time (from Earth) AU h m Distance (from Sun) AU Angular Size " Magnitude - Altitude ° Star Voyager graphic Comments It is in the same FoV with Jupiter in my binocular. It did not appear planetary at this magnification. I did not detect any color.

Target M57, Ring Nebula, NGC 6720 Constellation Lyr Category DSO: PN Time yyyymmdd.hhmm 20100815.0040 EDT Luminosity 35 Sols Magnitude 8.5 Surface Brightness 9/sq' Size 1x1' 0.6x0.4 ly Shape Nearly Circular Difficulty 3 Distance 1,500 ly Location Where is M13 graphic Star Voyager graphics References Deep Sky Observer’s Guide: 148, 150-151 Stars and Planets: 150, 190, 193, 262, 264, A5 Celestial Sights, Celestial Splendors: Binocular Highlights: 61 The Observer’s Sky Atlas: N13 Comments I couldn't ven detect it with averted vision. I rarely see the Ring in binoculars.