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General Astronomy => Beginners Forum => Topic started by: snowcadere on December 29, 2017, 03:51:27 AM

Title: Is This Neptune?
Post by: snowcadere 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?
(https://s10.postimg.org/gpz9cderp/0_attachment_00.jpg) (https://postimg.org/image/gpz9cderp/)
Title: Re: Is This Neptune?
Post by: outatnoha on December 30, 2017, 05:41:52 AM
Ummmmm . . . There is nothing there.
Title: Re: Is This Neptune?
Post by: neukascome on December 30, 2017, 04:59:21 PM
Well... that's what I was afraid of.
Title: Re: Is This Neptune?
Post by: esrescioripp 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
Title: Re: Is This Neptune?
Post by: Damon Brigham 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.
Title: Re: Is This Neptune?
Post by: olnceratge 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.
Title: Re: Is This Neptune?
Post by: tamamatte 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.
Title: Re: Is This Neptune?
Post by: Niro Hardy 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.
Title: Re: Is This Neptune?
Post by: Johnny Jeep 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.
Title: Re: Is This Neptune?
Post by: swittetsakee 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 (http://www.saguaroastro.org/content/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!
Title: Re: Is This Neptune?
Post by: olaralal 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.
Title: Re: Is This Neptune?
Post by: leypelepha 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.
Title: Re: Is This Neptune?
Post by: Jaimeylos Chiessa 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
Title: Re: Is This Neptune?
Post by: Matthew Danielson 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.
Title: Re: Is This Neptune?
Post by: presalacder 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?
(https://s18.postimg.org/qvjybt4rp/14_attachment_00.jpg) (https://postimg.org/image/qvjybt4rp/)
Title: Re: Is This Neptune?
Post by: Daniel Ross on January 16, 2018, 02:27:01 AM
Quote
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?
Well it seems to have a disc versus other pinpoint lights. What is your effective focal length here?

However, CdC stars do not appear to match quite as well (?)

Attached Thumbnails
Title: Re: Is This Neptune?
Post by: wallnewsspheryz on January 20, 2018, 08:50:46 PM
Maybe a longer exposure would bring it out.
Title: Re: Is This Neptune?
Post by: planvelsynchcest on January 20, 2018, 10:12:24 PM
I can't tell about the field, but the size of the disk and relative distance/brightness for Triton match my visual impressions in recent nights.
Title: Re: Is This Neptune?
Post by: ringnasingsimb on January 26, 2018, 01:09:24 AM
This is how it looks in Stellarium for my location at the same time. Seems to match.
Title: Re: Is This Neptune?
Post by: Jeff Swan on January 30, 2018, 06:04:39 AM
looks like you got it.
Title: Re: Is This Neptune?
Post by: Bill Godschalk on January 31, 2018, 06:53:47 AM
Looked at Neptune Friday and Saturday night from Cathedral Gorge State Park in east central Nevada. It was a tiny bluish-gray disk, with of course, no details. Was a bit too blurry due to mediocre seeing at 102X. Tried 229X but didn't do it any favors. Never tried my aperture mask because I could tell it wouldn't make any difference. Still too low on the horizon both times I looked. It was still nice to revisit an old friend. Also seen Pluto for the first confirmed time. I found and tracked the dot over Friday and Saturday night. Nothing to write home about except saying I saw the "dot!"
Title: Re: Is This Neptune?
Post by: Troy Furlong on January 31, 2018, 11:43:49 AM
@chrysalisI think if your image were rotated about 45 degrees to the right it would match mine.

Edit: ok, maybe not. at first it looked as though it would.
Title: Re: Is This Neptune?
Post by: Aoptimus Berhane on February 02, 2018, 02:53:55 PM
Here's a slightly better version. I realize it's nothing fancy, but it's the first time I've ever seen Neptune with my own eyes, so for me it's pretty cool. I didn't intend to go down the astrophotography path, but it is kind of fun.
(https://s9.postimg.org/ayz1e4sm3/22_attachment_00.jpg) (https://postimg.org/image/ayz1e4sm3/)
Title: Re: Is This Neptune?
Post by: housletica on February 09, 2018, 08:47:14 AM
Quote
it's the first time I've ever seen Neptune with my own eyes, so for me it's pretty cool.


I remember the first time I saw Neptune and Uranus through the eyepiece, I was floored by a sense of immensity. The Uranian light I was seeing had traveled 3 billion kilometers from the sun, bounced, and travelled another 3 billion kilometers to reach my retina. The Neptunian light had run an even longer round trip: 9 billion total kilometers.
Title: Re: Is This Neptune?
Post by: Daniel Ross on February 09, 2018, 09:25:15 AM
Quote
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?
This is a very good shot of Neptune! Triton would be inside the red oval drawn on this image.
(https://s13.postimg.org/adcxck98j/24_attachment_00.jpg) (https://postimg.org/image/adcxck98j/)
Title: Re: Is This Neptune?
Post by: bankrybettdog on February 09, 2018, 10:58:54 AM
Good job on that shot. I really had to enlarge the screen to pick up Triton.