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NV observing report 9/18/2019

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#1 GOLGO13

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Posted 18 September 2019 - 09:24 PM

Had very clear skies tonight. In fact, it's the first time I've seen the Milky Way for sure and a little detail at my location (an orange zone with a lot of local light pollution).

 

Since the sky looked so good I decided to lug the 10 inch dob up from my basement (which is two floors equivalent ...16 foot ceilings). 

 

So my new .7 reducer (Antares from ScopeStuff) works great with room to spare on the 10 inch. I had some really nice views of nebulas tonight. I do believe my 10 inch is currently setup in a way where the mirror must be pushed up a bit. Because I bought a 2 inch extension because I was having some issues with certain eyepieces in the past. Of course this is good news for NV.

 

Lagoon: Really nice structure. I wouldn't call it as good as the Lagoon at Okie Tex in my 10 inch dob or even my 5 inch refractor there, but it was pretty close as far as brightness. I recall better detail through the eyepiece but it's been awhile.

Swan: This was probably my favorite object of the night. It had very nicely detailed and defined structure.

Eagle: I could actually see the pillars of creation (just a bit). Especially the main one but the image was fairly small in that area with the .7.

Crescent: Nice view of this, not super exciting but that's what it is

NA nebula: Sweeping around this was actually quite neat. It's a totally different view. I really enjoyed it.

Veil: This wasn't that great really. I could see it, but the detail was pretty dim. One of my favorite things I've seen was the Veil with a 16 inch dob in a green sky. Just crazy detail. I could see that same section, but it was pretty dim.

M92: Like other globulars they look good, but not the same type of view you get with an eyepiece in a dark sky. I feel like Globulars (and maybe it's because it is lower power) look like photos of globulars rather than a visual view of them. I also think this maybe because stars get a bit bloated with NV and globulars are super tiny star situations. Not sure what you guys think of Globulars in NV. Of course, it's much brighter than without the NV in a light polluted sky. I think showing this to people who are not astronomy focused would be better than a more defined dimmer one.

 

Andromeda at 1x looked a bit better tonight.

 

I get my 6 inch F4 soon. I am hoping to keep that setup upstairs and not have to lug the 10 inch upstairs anymore.

 

The wind really picked up and it was getting a little cold so I called it for the night.

 

Really happy with that .7 reducer from Scope Stuff.


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#2 Mazerski

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Posted 18 September 2019 - 11:41 PM

Good report. I used the 0.7x FR in an Obsession 15 and it made a positive difference.

 

if I recall you have the Astronomik 642 IR... if so, make sure you use the 642 and look at the following as they look really good in IR. It’s possible M42 looks better with 642 over 6, 7 or 12 Ha. I’ll test again soon. You get the advantage of nebulosity + all the stars.

 

M57

NGC 40

Eskimo

M42

 

Note - I do think of all objects I have seen, M17 (Swan or Omega) is the best one of all... that thing is beautiful.



#3 chemisted

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Posted 19 September 2019 - 06:12 AM

Globulars will never look right at low power.  You need to use a barlow or similar lens system to get to the image scale that presents these star clusters with the detail they deserve.  Try it - you'll like it.


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#4 GOLGO13

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Posted 19 September 2019 - 07:39 AM

Are barlows proper or would powermates be better to use?

#5 chemisted

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Posted 19 September 2019 - 07:53 AM

I use Powermates but if all you have is a barlow that should be fine.



#6 bobhen

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Posted 19 September 2019 - 08:13 AM

Powermates do not take up in-focus travel like a Barlow, so that is a consideration.

 

With NV aperture is not as important because you have the light from the intensifier. Image scale both large and small is what will give you different experiences.

 

I use 3 telescopes at native FL and with the reducer…
A 4” refractor at 500 & 350mm FL
A 120mm refractor at 900mm & 625 FL
The Mewlon at 1700 and 2,400mm FL
A Barlow can also be used.

 

That gives me a pretty good range from very wide to large image scale

 

One other hint: with NV you can hunt “previously impossible” targets. It’s a somewhat different way of observing that might take rethinking or getting used to.

 

Bob


Edited by bobhen, 19 September 2019 - 08:14 AM.


#7 GOLGO13

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Posted 19 September 2019 - 08:20 AM

I have quite a few barlows, so ill stick with them for now. It will take some planning for objects. Ive never been good on that, but i have sky safari on my phone which helps.

#8 The Ardent

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Posted 20 September 2019 - 12:44 PM

Read Burnham’s Celestial Handbook cover to cover about 5x and you will be set.

#9 Gavster

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Posted 23 September 2019 - 01:47 AM

Powermates do not take up in-focus travel like a Barlow, so that is a consideration.

 

With NV aperture is not as important because you have the light from the intensifier. Image scale both large and small is what will give you different experiences.

 

Bob

My personal experience is that aperture is very useful for nv for smaller objects. With my 16 inch dob and c11 I can get much more image scale whilst still keeping the effective speed of the system fast. For nebulae and galaxies imo fast speeds (f3 or less) make a significant difference to the views. The jump in magnification from around 10x to 40x is really worthwhile for me.

 

My smaller scopes are great for framing larger nebulae such as the North American, California, heart and soul. But there are a limited number of objects this size. Given the much larger number of smaller objects, my bigger aperture scopes are generally the ones I use for nv now. (Particularly in spring galaxy season). Even on the Veil I prefer bigger image scale to really see the intricate detail.


Edited by Gavster, 23 September 2019 - 02:30 AM.

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#10 bobhen

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Posted 23 September 2019 - 07:03 AM

My personal experience is that aperture is very useful for nv for smaller objects. With my 16 inch dob and c11 I can get much more image scale whilst still keeping the effective speed of the system fast. For nebulae and galaxies imo fast speeds (f3 or less) make a significant difference to the views. The jump in magnification from around 10x to 40x is really worthwhile for me.

 

My smaller scopes are great for framing larger nebulae such as the North American, California, heart and soul. But there are a limited number of objects this size. Given the much larger number of smaller objects, my bigger aperture scopes are generally the ones I use for nv now. (Particularly in spring galaxy season). Even on the Veil I prefer bigger image scale to really see the intricate detail.

Maybe I should clarify a little…With NV aperture is not as important (as it is with "unassisted" observing) because with NV you have the amplified light from the intensifier that makes up for the light gathering of a large mirror when used “unassisted”.

 

Yes, image scale is important for small objects like galaxies etc. But unlike “unassisted” observing you can get image scale and “brightness” without a large telescope. The intensifier delivers enough light that more than makes up for that very large mirror. And, of course, that is one of the advantages of an intensifier over "non-assisted" observing: you get both portability and light gathering.

 

That does not mean that larger scopes aren’t better than smaller scopes for some objects when “both” are equipped with intensifiers. It just means that smaller scopes “with” an intensifier can deliver the same (and in many cases more) than larger scopes can when used “without” an intensifier.

 

When I want image scale, I use my Mewlon over my smaller refractors.

 

Bob


Edited by bobhen, 23 September 2019 - 07:04 AM.


#11 GOLGO13

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Posted 23 September 2019 - 08:17 AM

Do you guys think my C8 would work for certain objects then? I do have a 2 inch diagonal for it so I could also use my reducer with it.

 

So far my 10 inch dob works very well.

 

I notice a bit of resolution detail improvements with the larger apertures. I assume it's the same benefit we get for visual observing with glass.



#12 bobhen

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Posted 23 September 2019 - 01:25 PM

Do you guys think my C8 would work for certain objects then? I do have a 2 inch diagonal for it so I could also use my reducer with it.

 

So far my 10 inch dob works very well.

 

I notice a bit of resolution detail improvements with the larger apertures. I assume it's the same benefit we get for visual observing with glass.

A C8 will work. Most telescopes will work with NV. Just depends on what you want them to do.

 

You already have a 10” F 4.7 (1,200mm FL). So unless you want the larger image scale of the “native” C8’s F10 (2,000mm FL) the 10” would seem to be the scope of choice. You could also Barlow the 10” to get larger image scale.

 

Yes, resolution will improve with aperture "up to the point where seeing limits" it. For deep sky objects though it’s really about contrast and light gathering. And the enormous light amplification property of intensifiers means you can use strong filters to get huge boosts in contrast and you also don’t need a large mirror to get increased light gathering, when compared to using “just glass” – and that's a win/win for intensifiers.

 

Bob



#13 GOLGO13

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Posted 23 September 2019 - 02:23 PM

Yes...it's hard to say if the improved detail I'm seeing is because the image is magnified more or it's the fact of having better resolution from a larger scope. I just noticed that in my 10 inch the eagle showed more detail in general. I could see the beginnings of the pillars of creation, where I had to really look for it in my 6 inch. And in the smaller scopes it's pretty washed out. I wasn't barlowing though. Sometimes the barlow'd images get a bit too dim for me. Depends on the object. But I have not used the barlows much yet.



#14 The Ardent

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Posted 23 September 2019 - 03:08 PM

Last night I tried Van den Bergh 145 in Cygnus, a reflection nebula not far from the Coccoon nebula. No luck visual or NV.  Most reflection nebulae don't work with NV. 

 

Reflection neb NGC 7023 is a wonderful target for NV . Because it's a wonderful visual target. 



#15 Jeff Morgan

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Posted 23 September 2019 - 11:02 PM

Last night I tried Van den Bergh 145 in Cygnus, a reflection nebula not far from the Coccoon nebula. No luck visual or NV.  Most reflection nebulae don't work with NV. 

 

Reflection neb NGC 7023 is a wonderful target for NV . Because it's a wonderful visual target. 

 

I am finding the same thing. The Merope and Maia reflection nebula are good in the NVD. The Witchhead, not so much.

 

My theory is that the GaAs technology is not blind to blue - but gives no material boost. More trials needed.

 

But at this point on the aforementioned objects I am still preferring conventional eyepieces.



#16 11769

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Posted 25 September 2019 - 11:18 PM

I am finding the same thing. The Merope and Maia reflection nebula are good in the NVD. The Witchhead, not so much.

 

My theory is that the GaAs technology is not blind to blue - but gives no material boost. More trials needed.

 

But at this point on the aforementioned objects I am still preferring conventional eyepieces.

It's nearly blind to blue. Depending on the chunk of blue spectrum, a high end tube with a GaAs photocathode is a net loss on blue, even with the gain cranked all the way up. Depends on the tube too. There's a blinking clock with a deep blue LED display adjacent to a room where I do my NV testing and with dark adapted eyes, I can see it clearly cast its glow onto a wall. With a Gen 3 tube, the glow on the wall is at best about the same, often dimmer, or almost impossible to spot, again depending on the tube. 



#17 Jeff Morgan

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Posted 26 September 2019 - 12:45 AM

It's nearly blind to blue. Depending on the chunk of blue spectrum, a high end tube with a GaAs photocathode is a net loss on blue, even with the gain cranked all the way up. Depends on the tube too. There's a blinking clock with a deep blue LED display adjacent to a room where I do my NV testing and with dark adapted eyes, I can see it clearly cast its glow onto a wall. With a Gen 3 tube, the glow on the wall is at best about the same, often dimmer, or almost impossible to spot, again depending on the tube. 

 

I could believe that. My observing notes on two reflections nebulas:

 

Nov 9, 2018, Z16, Home: Merope Nebula - Interestingly the intensifier does pick up this reflection (blue) nebula. I’m guessing that’s it already so bright that the intensifier sees it. That being said I think I like the view through the 40 Paragon a little bit better for this object.

 

Nov 9, 2018, Z16, Home: Maia Nebula - As with the Merope nebula it is bright enough that the intensifier shows it plainly. Even with hydrogen alpha! However the view is still better in the 40 Paragon.

 

In retrospect, it is interesting that I picked up anything in h-alpha. It was probably in place by accident before the slew since I was aware of the nature of the Pleiades.




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