Michael A. Phillips' Astro Blog: neptune

Showing posts with label neptune. Show all posts

Saturday, October 3, 2015

Bright spots on Neptune

Back in mid July of 2015 it was brought to the attention of several amateur astronomers like myself that there are bright spots on the cloud surface of Neptune. A request was made by professionals to help observe these spots in red or narrowband IR. I have had a string of poor weather and didn't have a chance until mid September. On September 20th, I had some moderate conditions to try. My method was to shoot wide field with the CCD as seen here. I've superimposed an high-res RGB image on top to help identify Neptune. The brightest and closest 'star' to Neptune is about the 7 o'clock position (lower left) and is actually the largest moon, Triton.

If you read the stats, Neptune was 241.3 light minutes away at the time of this photograph. That's just over 4 light hours away. For fun here's a size comparison via the wikipedia page.

At that distance Neptune is only 2.4 arc minutes in size and the top image that I took is fairly close to what you might see in a moderate telescope at medium magnification.

After some wide-field CCD shots, I put in my high-res planetary camera and took some LRGB as well as Infra-Red (742nm) shots. Here's the aesthetically pleasing composite consisting of all 5 filters that also includes a Triton.

Finally for the detail oriented here's the full layout, including the sub channels used in derotation.

Also here's the alignment reference from the Neptune Ephemeris Generator (http://new-pds-rings-2.seti.org/tools/ephem2_nep.html)

Thanks for reading and please do some well wishes for more clear skies for me, they've been far and few between.

http://www.wunderground.com/history/airport/KRDU/2015/9/30/MonthlyCalendar.html?&reqdb.zip=&reqdb.magic=&reqdb.wmo=

If anyone is interested all source tiffs, sharpened files and WinJupos measurements are on my public Google Drive share located here and contained in a 30+MB .zip file - > https://drive.google.com/file/d/0B9dWDZG-h1gvZ2tGdUNKTWQ1eE0/view?usp=sharing

Friday, October 24, 2008

Neptune 2008-10-15

Observation logs

Object: Neptune

Planet

Origin:

ObservationManager - SolarSystem Catalog 1.0

Observer	Michael A. Phillips Mr.
Site	Home
Begin	2008-10-15 um 19:50:00-05:00
End	2008-10-15 um 22:10:00-05:00
Seeing	3 (fair)
Optics	C8i
Eyepiece	PowerMate (V=812.8)
Filter	Astronomik LRGB Color
Camera	DMK21AF04
Sitzung	2008-10-15 um 19:50:00-05:00

Visual impression

Neptune rises 1st and is dimmer than Uranus.Unfortunatley this makes adjusting to an object much harder. Finding was not as hard as I was thinking it was. A simple Precise-GoTo got me within the ~60* FOV. I double checked against Stellarium and was amazed that there it was! I was even more amazed to see it as a smallish disk visually. It's very dim, bluish and small, but there it was! RGB settings: RG - 3.418sec exp ; 928 Gain B - 3.418sec exp ; 1024 Gain 90s capture time per channel at above settings. RGB x 4 iterations = 3 captures per 'session' x 4 sessions. Therefore each RGB channel gets 4x .avi's stacked together. Each 90s capture resulted in 24 frames x 4 'sessions' in total about 100 frames per channel, best ~75% used (estimate) Darks taken and applied in Registax Lum for moons settings: Clear Filter (IR/UV Block) - 3.418sec exp ; 1024 Gain ; 50% Gamma 58 frames total and ~30-40 stacked Darks taken and applied in Registax

References

SETI reference:

Red Shift 5 Reference:

And CalSky reference:

Sessions: 2008-10-15 um 18:45:00-05:00

Begin:	2008-10-15 um 18:45:00-05:00
End:	2008-10-15 um 23:30:00-05:00

Weather:	Forecast called for S 4/5 and T 3/5 Actual S: 4-6 T: 2-3/5
Equipment:	I used: Ubuntu 8.04 Linux and custom coriander 8" Celestron C8i SCT DMK 21AF04 2.5x PowerMate Astronomik LRGB filters True Tek Color Filter Wheel with visu diag Since the 3 day stretch of good seeing in early Sept, I have used the T61 Also used WinXP and IC Capture with the TrueTek Hand Controller for > 1sec exposures
Comments:	To get Uranus and Neptune I had to move exposures beyond 1 second. Currently the custom coriander 1.0.0 does not support exposures beyond 1 second. Even at 1sec and 3.25fps I was unable to get usable data. As quickly as I could I switched to WinXP and IC Capture for camera control. A reboot and install of drivers burned some time, but a valuable lesson in prepareness. I did try to leverage previous whitebalance exercises on Jupiter for Uranus and Neptune. I found tracking and alignment horrible, but since finding 6-7mag planets isn't easy, I decided not to re-align. More and deeper exposures would have helped the moon shots.

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Observer: Michael A. Phillips Mr.

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