A very red Pluto

[SkyViking]

Hi everyone, here is an image I took of Pluto the other day:
[/URL][url]http://www.pbase.com/rolfolsen/image/125268154 (http://www.pbase.com/rolfolsen/image/125267774)

This image shows Pluto against the dense star fields of Sagittarius. The planet is noticeably red, a fact that was discovered in 2003 when it was observed that Pluto had undergone a dramatic surface change and suddenly featured a significantly redder hue than what had been observed in previous years.
An increase in the amount of ultraviolet sunlight breaking down methane on Pluto’s surface is thought to account for the redder hue, but the mystery will probably have to wait until 2015 when the New Horizons probe beams back the first clear pictures ever of this distant world.

Image details:
04/06/2010
180 x 10.5s
Taken with 10" Newtonian f/5.2 and Philips ToUCam Pro SC1 webcam
No filters, no guiding

Hope you enjoy, all comments welcome as usual.

Many regards,
Rolf

[Bassnut]

Cool, unusual to see Pluto.

[Clayton]

Nice to have a quality pic and information as well. Thanks for sharing Rolf

[kinetic]

Hi Rolf,

Webcams can be very weak in the blue and as you don't seem
to use a filter (IR at least), the image could be very red/ green dominant?

A lot of my modded webcam star field stuff had bad IR halos
without using an IR rejection filter.
Your image seems to be free of that though.
Have you done any G2V star calibrating? A lot of that field is
predominantly reddish stars.:shrug:

Steve

[SkyViking]

Hi Steve, yes I've had trouble taking shots without IR block filter too... Unfortunately my camera is only about 1/3 as sensitive as a 'real' CCD so I usually shoot without filters to gather every photon I can :)
I've found that the main effect of not using an IR block filter with the ToUCam is that interestingly it lowers the overall saturation, especially in the red. So for example stars that I know are red seem to become less red and more bloated than when I use an IR blocking filter. I had this problem with my recent Proxima Centauri image (http://www.iceinspace.com.au/forum/showthread.php?t=61598), where I ended up having to blend an image taken with IR block filter as a color layer on top of an identical luminance image taken without filter to get the colors right.

This particular image didn't seem too affected though. I'm confident that the colors are right, albeit not to a scientific degree of course (I have not done calibration).

Regards,
Rolf

[Dennis]

Hi Rolf

That is an excellent image for a non-tracking, unguided instrument when using such short exposures, even though the webcam has been modified. I am impressed by these results – well done.

However, because you have produced such good data, I compared the field to The Sky 6 Pro and I think that the object you have identified may not be Pluto? I think that a “better” candidate is the object that I have arrowed on a copy of your image.

Using The Sky 6 Pro, I think that the object you have identified is a star labelled as GSC 6269:1035 in The Sky 6 Pro:

GSC 6269:1035
Magnitude: 12.3
Equatorial: RA: 18h 19m 29s Dec: -18°12'44"(current)
Equatorial 2000: RA: 18h 18m 50s Dec: -18°13'00"
Source catalog: GSC catalog

Pluto is Magnitude 14.0 according to The Sky 6 Pro.

It is difficult to establish, but I think that the blue star just above what I think may be Pluto is a UCAC 2.0 Star, Magnitude: 14.38 at:

Equatorial: RA: 18h 19m 28.05s Dec: -18°12'41.74"(current)
Equatorial 2000: RA: 18h 18m 48.99s Dec: -18°12'57.84"

What do you think?

Cheers

Dennis

[astroron]

I have to agree with Dennis and Steve, Pluto is just not that Big:shrug:
I have been Observing Pluto for the last four days with a 16" Newtonian,6mm RADIAN eyepiece, (300XMAG), and Pluto at 14xmag is just a minescule dot compared to the field stars.
I took your image out to the scope last night, and I confirmed my view:thumbsup:

[Dennis]

Coincidentally, I was out last night (6th June) putting my gear, or more correctly myself, through its paces as my last session was around Oct 2009!!!!

I pointed the ‘scope at Pluto and grabbed a few test shots and was astonished at how many field stars there were – Sagittarius of course!

What a pleasant surprise it was then, then to find a post by Rolf and using his image, I was able to more confidently pin point Pluto in mine.

Cheers

Dennis

[astroron]

:hi:Dennis, would it be possible to publish one of your test shots with what what you consider is Pluto:question::thumbsup:

[Dennis]

Hi Ron

Okay – here it is. Not as clean as Rolf’s image but it does show Pluto as at 6th June. I’ve oriented the frame as close as I could to the aspect shown in Rolf’s image of 4th June to make a comparison a little easier. So many stars eh!

Cheers

Dennis

[astroron]

Thanks Dennis:thanx: Copied and printed for use at the eyepiece in the next couple of days:astron:

[astro744]

I use SkyTools3 Pro and also believe the object originally shown is GSC 6269:1035.

What time (HH:MM) was the original image taken. Pluto's movement over one hour is significant.

[Dennis]

Hi Ron

I think my image may not be of any real value to you, as Pluto will have moved out of the field by the time your skies clear?

I have tidied up my image and labelled a few stars and tried to orient it similar to Rolf’s so you can see how much Pluto has moved over the 2 days between Rolf’s image (4th June) and mine (6th June 11:30pm AEST).

Cheers

Dennis

[SkyViking]

Thanks Dennis, you're right! The one you've marked is indeed Pluto, and not the one I first thought it to be. Apologies to all for my mistake...:ashamed:

This is actually very interesting, I've just double checked in Starry Night and GSC 6269:1035 is not even on the map, in fact Starry Night shows no star brighter than magnitude 15 within 1 arcminute of Pluto at that time. Incredible - and very confusing.
This confirms a suspicion I've had for a while now. I've experienced similar difficulties before where the field I zoom in on in Starry Night looks significantly different from what I see in the eyepiece - very frustrating when star hopping (especially in Sagittarius!). There must be some errors in their database. Has anyone else noticed this? I'm just about to throw Starry Night out of the window now :mad2:
What's your experience with The Sky Dennis, is it more reliable in general?

At least the correct Puto is also reddish, so at least that observation still stands :)
Once again, I sincerely apologise for the confusion. I have updated my image on the website.

Regards,
Rolf

[Rob_K]

Rolf, I often experience the same thing with Starry Night - it's not in error, but limited by the catalogues it uses. For faint objects that I might be chasing, I use SN to narrow it down, but generate Deep Sky Survey views to confirm (usually in Aladin).

Nice shot anyway Rolf, Dennis too! :thumbsup:

Cheers -

[Dennis]

Hi Rolf

No apologies required, I know how easy it is to mistakenly identify such faint objects - I’ve done this myself. Image how difficult it would have been for Clyde Tombaugh if Pluto had been is Sagittarius back in 1930 (I think it was in Gemini) when he discovered it.

In terms of planetarium and observation planning applications, I like SNP for wide field views, the intuitive user interface and for the information it can deliver on various bodies.

The Sky 6 Pro is a nice, technical piece of software and I tend to use it for the fainter, more difficult stuff.

SkyTools 3 Pro is another of my favourite technical applications and the author keeps it very up to date with solar system events.

So, I use all 3 depending on what I want to do as no single one of them appears to do it all, or maybe how I want it to be done!

Thanks for posting your original, it helped me track down Pluto on my image of the 6th – the Forum is a terrific resource for sharing results and showing current objects of interest, so keep ‘em coming!:thumbsup:

Incidentally, even in The Sky 6 Pro the star GSC 6269:1035 (mag 12.3) is also listed as a mag 13 star from the UCAC2 and USNO databases, so there are definite discrepancies between the various catalogues once you get into the fainter stuff.:)

Cheers

Dennis

[kinetic]

Rolf,

it seems you have the colour thing sorted too if this animation
is a guide.:thumbsup:
If Dennis' LRGB is anything to go by most stars don't seem to change
colour, at least to my eyes. Halos ok too.
Your 10" optics must be almost free of chromatic aberration!

I remember having RGB sliders set to something like 26,32,40 in my
webcams (values 0-63 range) to account for the poor blue
sensitivity. This gave me a good approximation of white light on
Deep sky as well as Mars etc.
I must check this, it's written on the dome wall in texta :)

Steve

[SkyViking]

Thanks Rob, yes I use DDS myself when hunting really faint stuff like quasars. I thought a magnitude 13-14 object like Pluto was 'safe' to use Starry Night for, but apparently not so. I will definitely use DDS more in the future then.



Oh yes, at least we enjoy the luxury of knowing that Pluto actually exists! We pretty much just have to point and shoot ;)
And thanks for your planetarium software recommendations.



Thanks Steve, yes I have set the RGB values manually too I remember - some 4 years ago probably. That must be why I get the colours reasonably right. I completely forgot about that :)
Great animation too, it really moves a lot in just 2 days doesn't it.