Author Topic: Is This Neptune?  (Read 201 times)

snowcadere

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Is This Neptune?
« on: December 29, 2017, 03:51:27 AM »
I'm not sure...  I tried to photograph Neptune, but I couldn't focus the DSLR, which is a whole other question for another thread. Can anyone tell if one of these is Neptune?




outatnoha

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Re: Is This Neptune?
« Reply #1 on: December 30, 2017, 05:41:52 AM »
Ummmmm . . . There is nothing there.

neukascome

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Re: Is This Neptune?
« Reply #2 on: December 30, 2017, 04:59:21 PM »
Well... that's what I was afraid of.

esrescioripp

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Re: Is This Neptune?
« Reply #3 on: January 04, 2018, 05:37:26 PM »
I think the way it works, is you take a picture and then wait a few days to take another.. if the spot moves it is a planet, if not it is a star..

I love the idea of using digital cameras. I have a 5 inch refractor, and I have been taking pictures of pluto.. still need to stack them.. then flip between results to see pluto move around some.

Bill

Damon Brigham

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Re: Is This Neptune?
« Reply #4 on: January 08, 2018, 12:55:29 AM »
Neptune is noticeably blue and its tiny disk will show itself to be non-stellar at high powers.

olnceratge

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Re: Is This Neptune?
« Reply #5 on: January 08, 2018, 11:36:51 AM »
Looked at Neptune the last two nights. Both it and Uranus show as blue-green disks, small but definitely not starlike. I had the 11 inch on it at an outreach event Friday and just about everyone who viewed it could see the difference clearly.

tamamatte

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Re: Is This Neptune?
« Reply #6 on: January 10, 2018, 02:37:29 AM »
Thanks. I'm going to give it another try this evening. I do have a lot of light pollution, so that may be an issue.

Niro Hardy

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Re: Is This Neptune?
« Reply #7 on: January 10, 2018, 02:41:11 AM »
You have captured several light points. One of them MAY be Neptune. What is your objective diameter? What is your FL (or EFL)?

Neptune may not present much color in smaller scopes due to its size and relative dimness. In 12" it looks bluish grey but is very tiny (like 2") and can be hard to distinguish from stars.

Johnny Jeep

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Re: Is This Neptune?
« Reply #8 on: January 10, 2018, 11:35:49 AM »
Nexstar 8se
8", 2032mm.

The DSLR was attached as prime focus.
exposure 1 sec
iso 6400
10:33pmI had aligned the scope, then selected Neptune in the Goto and snapped a few photos. The challenge is that I can't see anything in the viewfinder or LCD until after the photo is taken, as the objects are too dim. Tonight I'm going to make sure I can find and identify it in the eyepiece first.

swittetsakee

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Re: Is This Neptune?
« Reply #9 on: January 10, 2018, 01:57:18 PM »
Quote
Nexstar 8se
8", 2032mm.

The DSLR was attached as prime focus.
exposure 1 sec
iso 6400
10:33pmI had aligned the scope, then selected Neptune in the Goto and snapped a few photos. The challenge is that I can't see anything in the viewfinder or LCD until after the photo is taken, as the objects are too dim. Tonight I'm going to make sure I can find and identify it in the eyepiece first.

That's a very good idea. Be sure you use enough magnification to discern a disc on an object that is only 2" across. Most people can comfortably see 3' separation....so you will need in the area of 150X-ish to be sure to tell Neptune from stars. In the 8" at 150,you will have a exit pupil 1.4 mm, pretty nice size for this purpose. You MAY see color, you MAY not...but you should discern a disc.This should nail it for you. Also, be aware that software may not be perfectly accurate, so you might need to pan around a bit in order to identify Neptune for certain.

You will not get a disc at prime focus though and will need to go afocal. From this website,

http://www.saguaroas...nt/formulas.htm

you can approximate the size of a 30' object (like sun or moon) as ca 18.3 mm. This means the size of Neptune in your prime focus image would be ca (18.3*2)/(30*60) = 0.02 mm.

Good luck ! ! !

And post your Neptune photo!

olaralal

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Re: Is This Neptune?
« Reply #10 on: January 11, 2018, 11:30:45 PM »
Not being an astrophotographer, the natural question I have is why trust the Goto? It is unlikely to center so well that you will have the planet properly framed. Why not put in a high powereyepiece and identify Neptune visually, center it and track while rigging for photography?

Neptune is small as mentioned aboveand rather blue. In darker skies and high poweran8" will reveal Triton as well.

leypelepha

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Re: Is This Neptune?
« Reply #11 on: January 13, 2018, 03:03:58 PM »
It really depends with the goto. Some nights I can get it really dialed in, others, not so much. But your suggestion is what I intend to try tonight, clouds permitting.

Jaimeylos Chiessa

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Re: Is This Neptune?
« Reply #12 on: January 14, 2018, 05:07:18 AM »
FWIW, I have been able to pick up (visually) Neptune as a tiny purplish disc at 166x in my 6SE, so it is absolutely within the capability of your 8SE.
Never tried any astrophotography so can't offer any feedback there.
Sent from my D6603 using Tapatalk

Matthew Danielson

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Re: Is This Neptune?
« Reply #13 on: January 15, 2018, 03:33:02 PM »
"Never tried any astrophotography so can't offer any feedback there."

For now the photography thing is just documenting what I have seen, rather than getting great photos. I'm much more into the visual eyepiece viewing. Still, it is fun when you plug that memory card into the PC and and find out you got a really cool shot.

presalacder

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Re: Is This Neptune?
« Reply #14 on: January 15, 2018, 09:33:53 PM »
I tried again tonight. I think I got it, but I'm not sure. This is as high as the magnification will go with my DSLR. If that is Neptune, that little dot right next to it could be Triton?