Is most of the sky this boring?

[gorann]

A clear night! So out into the obsy!

The EQ8 hummed as it should (sounded odd the other night) and the 2-star alignment was "successful" according to the SW handset, so I turned the rig towards tonight's target: the Ghost nebula (Sh2-136) and took a 1 min sample exposure at ISO 12800. Nothing there resembling the target. Did a 3-star alignment, also "successful". Another exposure and nothing there as far as I could tell. But, by then it was 7 pm and my wife had taken on the task of making dinner and it is Saturday night, so I though, what the h-ll, must be something interesting in there, and started the exposures.

We saw two episodes of the Unabomber on Netflix after dinner and here is what I got after nearly 3 hours (28 x 6 min at ISO1600 with my Canon 60Da on a 5" refractor). I now finally found my target and I am shooting away on it now, but this made me think, is this is what the rest of the sky looks like (outside our famous targets)? I did my best and cannot find any nebulosity in the data.....

Obviously, I also have to figure out what the mount is up to. Possibly the pier is not in level since the frost in the ground could have shifted my 200 kg of concrete - it is -8°C here right now.

Cheers

[Pig]

Do you think it is boring ?  Maybe you should take a second look at your image as there is at least one star missing ?

[Floater]

I don’t think that’s boring at all, Göran. ?

But I think I know what you’re getting at Shaun (Pig). ?

 

[Luna-tic]

Well, it IS called the GHOST nebula.  

[Gina]

I've had more times when I can't find the object I'm looking for than when I can.  Unless it's something big and bright like The Great Orion Nebula.  The Ghost doesn't come into that category.

[gorann]

Yes, Gina it is quite frustrating when it happens. What I had to do now was to post a jpg frame on Astrobin to get it plate solved. Turned out I was 3 degrees south of my target (still have to figure out why). Now, when I finally found it the moon has come up. Well, another clear sky is promised for tomorrow....

Good night my friends

[michael8554]

Even on my permanently mounted rig I always GoTo a recognisable star near the dso, centre it, then Synch, then GoTo the dso.

Always on target.

Michael 

[Jannis]

1 hour ago, gorann said:

Obviously, I also have to figure out what the mount is up to. Possibly the pier is not in level since the frost in the ground could have shifted my 200 kg of concrete - it is -8°C here right now.

200KG? And here i was worrying with my ~3000KG concrete pier...

Level or not should not matter much on an EQ mount i think, naturally as long as it's polar aligned. I guess a new polar alignment will quickly tell if the frost have shifted your pier.

Since i got the pier mount i haven't had much issues with goto, but whenever i'm in doubt or it's somehow off i select 3 brighter stars in a triangle close around the target and center them. I'd expect your EQ8 to be more precise then my HEQ5 with this though...?

[SteveBz]

8 hours ago, gorann said:

Yes, Gina it is quite frustrating when it happens. What I had to do now was to post a jpg frame on Astrobin to get it plate solved. Turned out I was 3 degrees south of my target (still have to figure out why). Now, when I finally found it the moon has come up. Well, another clear sky is promised for tomorrow....

Good night my friends

Hi Gorann, 

you can install astrometry.net directly onto your pc or laptop and plate solve locally. It's much faster because you tell it where to start, often less than 30 secs.

Then you can think of new things to do with it, like auto-check your polar alignment.

Steve.

[alexbb]

There's also nova.astrometry.net

[ollypenrice]

The Gnomuses and I took a similar picture here a couple of months ago! My fault entirely.

Doing the 400 hour Orion mosaic involved no small amount of this kind of imaging, however...

ly

[gorann]

40 minutes ago, ollypenrice said:

The Gnomuses and I took a similar picture here a couple of months ago! My fault entirely.

Doing the 400 hour Orion mosaic involved no small amount of this kind of imaging, however...

ly

Good thing is that I now got 12 Gb of data from last night to play with since I was running my triple rig with the Samyang 135mm and Canon 300 mm sitting next to the refractor. So 477 subs of two targets with three cameras. It could be that the accidental first target turns out more interesting in the wide field telephoto images - but it will take most of the day for PI to stack the 313 x 1 min subs from the Samyang.

[gorann]

To prove that I finally found the Ghost last night, here it is. Unfortunately at that time the moon was coming up and I only got 3 hours with the 5" refractor (and a Canon 60Da) Obviously, I have to get more data.

[ollypenrice]

Just get lots and lots of data and you'll really love this target. It's one of the greats.

Olly

[gorann]

1 hour ago, ollypenrice said:

Just get lots and lots of data and you'll really love this target. It's one of the greats.

Olly

Will do Olly, next time I find it

[gorann]

20 hours ago, Jannis said:

200KG? And here i was worrying with my ~3000KG concrete pier...

Level or not should not matter much on an EQ mount i think, naturally as long as it's polar aligned. I guess a new polar alignment will quickly tell if the frost have shifted your pier.

Since i got the pier mount i haven't had much issues with goto, but whenever i'm in doubt or it's somehow off i select 3 brighter stars in a triangle close around the target and center them. I'd expect your EQ8 to be more precise then my HEQ5 with this though...?

Jannis, 3 tonnes of pier? Did you get a truck to unload that? I mixed the base myself with a shovel and I actually have no idea how much it weighs since I mixed in a variety of stones and boulders lying around, my guess being at least 200 kg. However, when it comes to frost heave, I do not think the weight matters much - that is all down to the physics of ice having a lower density than water. At our latitude you need to get it down 1.5 meters below the surface to be sure - but maybe you did that? Still, I may add some more this summer just to feel good....

[gorann]

23 hours ago, Pig said:

Do you think it is boring ?  Maybe you should take a second look at your image as there is at least one star missing ?

I am still looking for that missing star , could you give me a clue....

[gorann]

Friends,

I must now officially declare that the area 3 ° South of the Ghost nebula is virtually devoid of any particularly interesting features whatsoever. Here is my Samyang 135 wide field image (171 subs totaling 3 hours at f/2) of that area. OK, there is a little bit of dark nebulosity there...

Maybe this is an idea for an imaging challenge? Find the least exciting area of the universe!

[wimvb]

Nice images, both.

I agree with @SteveBz: add platesolving. If polar alignment is good, platesolving will put you right on target in no time. As the software builds the skymodel, it just gets more accurate. Yesterday, I targeted the heart neb and needed just a few iterations. When I after that slewed over to M82, I just needed one correction to get it smack in the middle if my (small) sensor. (But unfortunately no good images, as tfhe moon was up)

Btw, I have a similar image (taken before I started using platesolving), but closer to the ncp. It shows that outside of the plane of the Milky Way, there really are fewer stars. And any dark nebulosity is harder to find.

6 minutes ago, gorann said:

 

 

[Jannis]

3 hours ago, gorann said:

Jannis, 3 tonnes of pier? Did you get a truck to unload that? I mixed the base myself with a shovel and I actually have no idea how much it weighs since I mixed in a variety of stones and boulders lying around, my guess being at least 200 kg. However, when it comes to frost heave, I do not think the weight matters much - that is all down to the physics of ice having a lower density than water. At our latitude you need to get it down 1.5 meters below the surface to be sure - but maybe you did that? Still, I may add some more this summer just to feel good....

Glad to see you finally found the target!

And no, i mixed it myself, although i used a concrete mixer, so not by hand (i gave that up quite fast). I hope i will never have to remove it though, haha...
Due to my pier height i didn't want to take any chances. I didn't get as deep as 1.5M, but then the last 6-7 years i haven't really been as cold as it used to be. I have to admit i haven't done a new polar alignment since the fall though, but haven't missed a target yet either. I usually just select "park to current position", shut it off, and next time i'm out the target is still well within FOV on my APSc and 1000mm FL.

[gorann]

11 hours ago, wimvb said:

Nice images, both.

I agree with @SteveBz: add platesolving. If polar alignment is good, platesolving will put you right on target in no time. As the software builds the skymodel, it just gets more accurate. Yesterday, I targeted the heart neb and needed just a few iterations. When I after that slewed over to M82, I just needed one correction to get it smack in the middle if my (small) sensor. (But unfortunately no good images, as tfhe moon was up)

Btw, I have a similar image (taken before I started using platesolving), but closer to the ncp. It shows that outside of the plane of the Milky Way, there really are fewer stars. And any dark nebulosity is harder to find.

 

Yes, I was thinking of starting plate solving in some way but I rather keep it low tech and run the mount from the handset. It has worked well before. When I did the three star alignment the SW handset told me that i was about 2 min off in Dec and 4 min of in RA, if I remember it right. I thought that would be good enough - but maybe not?

Cheers

[gorann]

On 1/7/2018 at 01:47, Jannis said:

200KG? And here i was worrying with my ~3000KG concrete pier...

Level or not should not matter much on an EQ mount i think, naturally as long as it's polar aligned. I guess a new polar alignment will quickly tell if the frost have shifted your pier.

Since i got the pier mount i haven't had much issues with goto, but whenever i'm in doubt or it's somehow off i select 3 brighter stars in a triangle close around the target and center them. I'd expect your EQ8 to be more precise then my HEQ5 with this though...?

Is this a function of the SW handset? What do you press after having centered on a nearby star to make the mount adjust its sky model? Also see my comment about polar alignment to Wim above. Would a few minutes off be a problem?

[alexbb]

20 minutes ago, gorann said:

Is this a function of the SW handset? What do you press after having centered on a nearby star to make the mount adjust its sky model? Also see my comment about polar alignment to Wim above. Would a few minutes off be a problem?

I suppose this is the 3 star alignment.

 

23 minutes ago, gorann said:

Yes, I was thinking of starting plate solving in some way but I rather keep it low tech and run the mount from the handset.

You could still upload a just shot image to nova.astrometry.net and see where you really are pointing to. No need to control the mount from the computer.

I still control the mount with the handset too and guide through ST4, even though I can fully control it with EQMOD through USB.
When I need to center a target , I register the image within a larger area containing the target and then adjust until I'm satisfied. I find this method maybe the most fail-proof.
I develop software for a living and I would describe many astro-apps as.. not the most reliable and the UX (user experience).. not the friendliest. The reliability seems to improve in time, but I can't say the same about the UX.

[Jannis]

16 minutes ago, moise212 said:

53 minutes ago, gorann said:

Is this a function of the SW handset? What do you press after having centered on a nearby star to make the mount adjust its sky model? Also see my comment about polar alignment to Wim above. Would a few minutes off be a problem?

I suppose this is the 3 star alignment.

No, this isn't the standard 3 star alignment i'm referring to. Correct me if i'm wrong, but a 3 star alignment in a triangle close to the target would be less then ideal since the 3rd star is to compensate for tilt (say if the mount is polar aligned well, but the scope is still pointing a bit up). I never usually do a new 3 star alignment unless i've released the clutches, changed the scope, lost power, or like here the other day when i managed to run my scope into the pier being overly optimistic with ignoring flipping... :'(

You have the function on the SW controller (note that i use synscan V3 controller, i don't know if V4 is the same), and the target does not necessarily need to be a star). I use stellarium to control my SW controller*, and so it's very easy to quickly slew to a brighter star close to the target. Once slewed stellarium will show you the mount position to be dead on the star. If the mount is off, press and hold ESC for a few sec until "recenter last goto target" shows up** (wait until it stop flashing before re-center), recenter using the arrows (you can adjust the speed. You'll also see the mount move away from the star in stellarium) and press ENTER. If success, you'll now see that the mount jump back to the target in stellarium***. Proceed to another star if you feel it's needed.

* Not needed, but it makes it a whole lot easier. Ever tried to slew to a specific star with the controller alone? It's a nightmare to browse...
** sometimes you might need to press and hold ESC two times.
*** Sometimes it does not jump back to target. This usually does not happen, but it have happened a few times. It can either mean it did not save the position, or that stellarium does not show it. To confirm if position was saved, slew to same target again, the mount should not move. If it does, recenter it again.

[alexbb]

I see, never heard about this feature. Good to know!