Faint star hunting

[N3ptune]

This is a new image of my sketch along with another picture I found. The match from what I saw is not bad, better then expected.. my telescope is supposed to be limitated at magnitude 15 and the stars from A and G are accurate for sure.

There is something wrong.

[Stu]

6 hours ago, N3ptune said:

This is a new image of my sketch along with another picture I found. The match from what I saw is not bad, better then expected.. my telescope is supposed to be limitated at magnitude 15 and the stars from A and G are accurate for sure.

There is something wrong.

Yes, something doesn't look right. I doubt you will see mag 18 stars in your scope, what are your sky conditions like?

Which eyepiece were you using? If we can establish the field of view then it might be easier to see what's going on.

[N3ptune]

Hello Stu, I saw all the stars from A to F with my telescope, 8 inches with a limiting magnitude of around 14 - 15 in perfect conditions. Some stars from my sketch were really faint but they were there, clearly visible, F and ? and G required averted vision not the others.  (That's why they have a little line over them, they were the faintest stars I could see in the FOV)

The stars on my sketch are pretty accurate with the 2 images, (It can't be a coincidence, it's too close) especially the triangle A and the optical double star G.

Let's take the triangle A for instance, using John's record of magnitude, I should not even be able to see these 3, but they are clearly there, no doubt about the A triangle...

[mdstuart]

Interesting thread.

I can get to mag 15 just in mag 5 skies with my 16 inch dob overhead..

Get a motorised mount and a fast video camera and you will go much fainter.

The new web telescope can see the heat of a bee on the moon. Not sure what magnitude that equates to.

Mark

[Stu]

On 20/07/2017 at 02:59, N3ptune said:

Interesting report thanks for sharing it.

Has for me, my first stem was a semi-failure, this is my sketch of the stars surrounding the Ring Nebula, but my stars aren't at the same place has the existing recordings. Although, it could be a code 18.. these stars from my sketch were so faint, I could see them only with averted vision, invisible most of the time and maybe like you Nyctimene, visible 20% of the time. I used 80x magnification to produce my sketch xcel lx 25mm 60d AFOV.  Still an interesting exercise.

Update #3 - After a few rotation it makes more sense, some faint stars match the recordings. I don't have time to study the images further.. 

 

Neptune, I'm just trying to figure this out.

Can you confirm a few things....

Firstly what is your naked eye limiting magnitude i.e. Dimmest star you can see overhead without optical aid?

Second, which eyepiece were you using so we can figure out the field of view of your sketch which would help confirm things.

The positions of the stars look significantly further away from the Nebula than the diagram, was this as you saw them?

Thanks  

[N3ptune]

Hello Stu,

Yes it's true I need to provide more details.

With naked eye at home I can see up to around magnitude 5 or brighter. For the Pleiades, I can see 6 stars, the one I cannot see is Calaeno which is around 5.54 magnitude. For my sketch I used my Xcel-LX 2x barlow with my Xcel-LX 25mm eyepiece, 80x magnification, 60d AFOV this should be around 2700 arc seconds of sky, with my 203 x 1000 newtonian from my signature.

OTHER FACTORS:

- I had to draw really fast because of the mosquitoes, so the position of stars is most likely, not perfect ... but still I am confident it's far from wrong.

- Also maybe the AP will show a larger nebula then what can see with 8" light gathering and human eyes, this could be an argument too...

- And finally, I could be bad at positioning stars on the paper but could the Eyepiece or the telescope distort the FOV?  (Just checking)

 

 

[N3ptune]

Ahhh god.. I think you are right Stu.

The field of view from my sketch is much much wider then john's AP.

[mdstuart]

I checked last night. I could get to m14.7

No central star ?

I can see the one in M27.

Mark

[Stu]

1 hour ago, mdstuart said:

 

I checked last night. I could get to m14.7

No central star ?

I can see the one in M27.

Mark

 

That's good going Mark

I think I've seen the one in M27, seems to be Mag 13.5? Is that correct?

[mdstuart]

Yes the central star is quoted at 13.5 it's still hard but definitely there.

The nebula in M27/57 makes seeing the star harder than if the background was black.

Mark

[Stu]

7 minutes ago, mdstuart said:

Yes the central star is quoted at 13.5 it's still hard but definitely there.

The nebula in M27/57 makes seeing the star harder than if the background was black.

Mark

Thanks Mark. Need to check back through my reports, I'm sure I remember seeing it but may be mistaken.

EDIT Just checked my 'Devon Jollies' report and I did catch it at the limit of averted vision in the C8 Edge under Mag 20.5 ish skies, along with two other stars apparently  

[John]

I've seen the central star in M27 with my ED120 and relatively easily with my 12" dob. It's not a walk in the park with the smaller scope but is quite a bit more accessible than the central star in M57 I think.

My 12" dob gave similar results to the ones that Mark achieved the other night - I got down to the mag 14.7 stars but no further.

Mind you, that means that Pluto might be "on" if I take the time to observe carefully and sketch the star fields over a number of sessions.

[alan potts]

I would like to try for that little galaxy that is in the shots at the top of the page, can't say I have seen it up to now but it may well be outside the FOV when i was doing so much on M57.

Alan

[alan potts]

3 minutes ago, John said:

I've seen the central star in M27 with my ED120 and relatively easily with my 12" dob. It's not a walk in the park with the smaller scope but is quite a bit more accessible than the central star in M57 I think.

My 12" dob gave similar results to the ones that Mark achieved the other night - I got down to the mag 14.7 stars but no further.

Mind you, that means that Pluto might be "on" if I take the time to observe carefully and sketch the star fields over a number of sessions.

John, I have seen Pluto without any doubt, I just didn't know which point of light it was though.

Alan

[jetstream]

Last night I did some faint star observing for a while and the 10" VX got down to 14.7, which was inspiring. I made some improvements with the 15" and held the upper end 15's in direct vision for quite a while. No central star though...mind you I wasn't really trying for it either and the 7mm KK was down at the house.

I was looking at the galaxy Alan mentioned above which is often overlooked.

[alan potts]

Gerry,

I am sure with me it has been there but been out of direct line of site, coupled with I never knew it was their until i read something by one of the Dob Mob, Calvin I think, who pointed it out to me and now I have looked it up. I take an atlas out with me most times, it may well pay to actually look at it next time.

Alan

 

[N3ptune]

Hello, i tried a sketch again to point some faint stars.. but I am having trouble comparing my sketch with the various pictures.. 

This time I used 203x1000 newtonian, 4.7mm 82d afov = 212x. I know the A star war a rally faint one and only visible with averted vision, but definitely there, for the rest i don't know.. espacially the D, it may not even exist.

I guess I need to try again. John your image with the different magnitudes, is it from a newtonian.. (upside down) ?

[Stu]

40 minutes ago, N3ptune said:

Hello, i tried a sketch again to point some faint stars.. but I am having trouble comparing my sketch with the various pictures.. 

This time I used 203x1000 newtonian, 4.7mm 82d afov = 212x. I know the A star war a rally faint one and only visible with averted vision, but definitely there, for the rest i don't know.. espacially the D, it may not even exist.

I guess I need to try again. John your image with the different magnitudes, is it from a newtonian.. (upside down) ?

This should be a Newtonian view (upside down) with the correct field of view for your 4.7mm 82 degree eyepiece and scope combination.

Shown with mag 13.0, 14.0 and 15.0 stars showing. Seems you are seeing below mag 13 just from the numbers of stars?

EDIT Have put correct images in for UK not Sydney, had SkySafari set incorrectly  

 

 

[jetstream]

17 minutes ago, Stu said:

This should be a Newtonian view (upside down) with the correct field of view for your 4.7mm 82 degree eyepiece and scope combination.

Shown with mag 13.0, 14.0 and 15.0 stars showing. Seems you are seeing below mag 13 just from the numbers of stars?

EDIT Have put correct images in for UK not Sydney, had SkySafari set incorrectly  

 

 

Great images Stu, question- what is the mag of those faint stars tight to M57 at the bottom (3 in a row) and one up to the left (very tight to the neb)?

[Stu]

6 minutes ago, jetstream said:

Great images Stu, question- what is the mag of those faint stars tight to M57 at the bottom (3 in a row) and one up to the left (very tight to the neb)?

Do you mean these Gerry? Mag 14.4?

[jetstream]

The three on the bottom in a row(last one near the "-" sign and the one up and to the left at the neb edge). Thanks Stu.

[N3ptune]

Thanks Stu that's really interesting the 3 images with magnitudes 13, 14 and 15, it gives me a much better idea. My latest "A" star from my sketch looks like the one pointed by the red arrow on your image, can you get the magnitude for that specific star on your application?

This would be close to the limits of my eyes and instrument.

Thanks.