456 replies to this topic

[Jeff Morgan]

Another view of the Cave Nebula (and I still can't visualize the Cave!)

 

Compare this to the image taken through the Takahashi Epsilon on Page 2. This image has less ISO, a slower focal ratio - but more aperture.

 

Even with the Magic Eyepiece, aperture still matters.

 

Provided of course the subject still fits in the field of view 

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[gatorengineer]

Thanks for sharing Jeff. Great pics..

[Jeff Morgan]

Hi Jeff,

Nice pics   

You will soon be able to make a catalog of all the Sharpless pics you took with your NVD

 

That would be a fun project! I have been working down the catalog visually, up to 299 at last count ...

 

The remainder are in Sagittarius, so hopefully this summer I can complete the Sharpless Marathon.

 

Most of these objects have designations in other astronomical catalogs: NGC, Messier, LBN, etc. However, Sharpless seems to be the most comprehensive for emission nebula, so I decided to "restate" most of my nebula observations using those designations. In a few famous cases I have stuck with the more popular catalogs. Not too many people know that Sharpless 2-281 and M42 are one and the same for example.

 

Here is Sharpless 2-162 for your viewing pleasure.

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[Jeff Morgan]

Sharpless 2-168 in Cassiopeia. Kind of sitting out there on its own in a hydrogen alpha "dead spot" and as such jumps out visually. Although it does not stand out in the photo, visually it appears to be bordered by a very dark lane, which could just be a contrast effect.

 

Easy to find, makes a nice squat triangle with Beta Cass and Caroline's Rose.

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Edited by Jeff Morgan, 30 May 2020 - 08:48 PM.

[Jeff Morgan]

The Pacman. At least on this one I can see the namesake.

 

I wonder if this one had a common name before the game was invented?

 

Or if in 100 years amateur astronomers will ask "what the heck is a Pacman?"

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[Wildetelescope]

Still waiting for the last piece of the TV NV adapters that Will let me attach to an eyepiece or filter.  My 12 nm H alpha filter is here in good shape.  In the mean time, I went out with the PVS 14 last night to see what I could see at 1x. Had the PVS 14 attached to my Manfrotto tripod with floating head.   Below are a series of images that my son grabbed that captured a satellite? Not something I could see visually.   You can also see Vega and Lyra around the 4 o'clock region.  For context, by naked eye I can just BARELY make out Sheliak and Sulafat.  These images were taken with the iPhone with exposure set to ~1/3 and duration of ~6 seconds using Nightcap. The Fonemate adapter works fine is is really stable.  No filters or magnification.  Clearly I am seeing a bunch more stars than I normally do:-)   I have also see a lot more meteors during a session.  Need to work on camera settings and get the rest of the gear going, but this is certainly fun. Darn thing kept kicking into auto-gain.  Still working through all that.  I can actually take this image and compare it to a star chart and have it be meaningful.  I think I am going to have some fun star hopping.  This is clearly adding another dimension to observing.

 

[Wildetelescope]

 

Here is one with Lyra centered.  This was just taken with everything set to auto. One of the first images.  Kind of neat.  Can't see the ring specifically at this low mag, with no filter, but I can certainly see the area where it should be:-). Pretty cool!  In this image, Lyra is relatively, probably around 30 degrees from the horizon.  

 

JMD

[Jeff Morgan]

The HorseHead nebula is always a crowd pleaser. My first time seeing it was the 1996 WSP. After being shown the object in a 22" scope, I knew what to look for and rapidly tracked it down in my 10" scope.

 

Over the years I have seen it many times, but of course always in the limited fashion of averted vision. And never from my SQM 20.5 back yard. Of course the SQM value is the zenith value. Since I live north of town Orion is usually in the brightest part of my local sky, an SQM of in the high 19's may be more accurate.

 

Since getting the NV eyepiece, from that same back yard I have never failed to see it as a direct vision object, often with the Flame Nebula and Alnitak (Zeta Ori) framed in the FOV. Scopes used? Everything from my 16" down to a 135mm telephoto lens!

 

And after four years of NV astronomy, I never get tired of that view.

 

This view was a little dark on the ISO. I had meant to re-shoot it during the 2019/2020 season, but never got to it. 

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[Jeff Morgan]

Here is an old frame I came across, took me a couple of minutes to figure out what it was: The core of the Heart Nebula (Sharpless 2-190) with the Takahashi Epsilon.

 

Unfortunately, not enough FOV for the entire Heart, let alone the Heart/Soul complex. Definitely makes the case for "different game, different guns".

 

I also inadvertently discovered the White Balance adjustment in the NightCap phone app. Makes it look almost like a green NV image! Taking the advice of Ray Taylor, I now set that balance between 4000 and 4200 (the slider control is not terribly precise without a great fuss) which gives the white phosphor tube a very pleasing tint matching the visual image more closely.

 

A bittersweet image as I just shipped the Epsilon to a new owner. The sweet part is my Mike Lockwood 16" f/2.8 mirror set arrived this week. The Tak would be crowded between that Dob and my Canon 300mm telephoto. With my house is starting to look like a telescope warehouse, I made the decision to sell.

 

The Epsilon is a great NV scope I could heartily recommend. A blazing f/2.8 and razor sharp to the edge of field. Easily comes to focus using the Tak Wide-T adapter (which accepts 2" filters) and a Canon-C adapter. Approach the collimation as if it were a regular Newtonian, and you will do fine. My collimation held over a year, almost two dozen observing sessions.

 

I miss it already.

 

 

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[GeezerGazer]

Jeff, your image above is actually two distinct nebulae.  You have the heart of the Heart Nebula, Sh2-190 or IC 1805 and you have the Fishhead, IC 1795 or NGC 896 at the western most edge of the Heart.  Next time you are out with your 16", use a barlow and take a pic of the Fish Head.  With 16" aperture, you should be able to clearly show what "appear" to be three or four H-a pillars that extend out of the very end of the Fishhead, near the small bright spot in your image above. I thought for a long time that they were actually pillars, but apparently not, when compared to this long exposure, false color, NASA image-of-the-day, taken by Alan Pham:  https://apod.nasa.go...d/ap190731.html

And here is a 6 hr. AP photo by Chuck Ayoub taken using only an H-a filter which more closely  relates to what we see with NV:  https://en.wikipedia...eart_Nebula.jpg

 

I was able to photograph it in 2018 using my ST 120, 12nm filter and Barlow (46x).  But this image is cropped, which essentially increases magnification while reducing resolution, to reveal what I'm talking about.  I look forward to many more of your images.  Ray

 

Edited by GeezerGazer, 05 June 2020 - 06:28 PM.

[GeezerGazer]

This is Barnard 312, a dark nebula that is tough to see with a glass eyepiece in a modest aperture.  NV makes it very obvious.  Here's a comparison, long exposure AP image that took 12 hrs. of imaging to produce.  

 http://astrophoto.ne...llation-scutum/

I took the image below with my iPhone XR, in NightCap, ISO 80, 1/12s exposure averaged for 15s using an 8" Newt with ASA reducer at f:2.8.  Dark nebulae are a lot easier with NV!  I would name this one Mt. Fuji. 

 

[slavicek]

This is Barnard 312, a dark nebula that is tough to see with a glass eyepiece in a modest aperture.  NV makes it very obvious.  Here's a comparison, long exposure AP image that took 12 hrs. of imaging to produce.  

 http://astrophoto.ne...llation-scutum/

I took the image below with my iPhone XR, in NightCap, ISO 80, 1/12s exposure averaged for 15s using an 8" Newt with ASA reducer at f:2.8.  Dark nebulae are a lot easier with NV!  I would name this one Mt. Fuji. 

 

IMG_E5948.jpeg

Mt. Fuji is fine with me  . I have the privilege to spent few days at Mt. Fiji, and it was very romantic!

[Jeff Morgan]

One of the fun things about this technology is the "5 Minutes Before Bed Session".

 

Imagine the end of a busy day when you normally would not have a chance to do any astronomy. Schedule, fatigue, social obligations, whatever. Life happens, and sometimes it conflicts with clear skies.

 

Not an insurmountable obstacle for the NV Astronomer. Just grab a low power lens, maybe a filter, and go outside for a couple of minutes for a quick look before turning in.

 

This exposure was guided, the lens and NVD were mounted on a scope ... but the view is substantially correct for the quick hand-held session I just described. In this case using a Canon SLR lens giving about 1.8x magnification, absolutely wonderful for constellation-level viewing.

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[Jeff Morgan]

Open clusters can be a mixed bag. Not because of the nature of the image intensifier, but rather the varied nature of open clusters. Sometimes, NV does not bring much to the table and I prefer the conventional view. Sometimes I use both for different "character" to the view - especially for the brighter clusters with notable color tints. In general:

 

1) More detachment is better for NV. The reason is NV brings out so many background/foreground stars the cluster just blends in instead of standing out. The technology becomes a victim of its success!

 

2) Richer is better for NV. For a sparse cluster, not much extra to bring out, especially if the cluster is already "bright". 

 

3) Range of magnitudes is better for NV, similar reasoning to Rich vs. Sparse. For example, M29 is not a very good NV candidate for the last two reasons.

 

4) Concentration. More is generally better, though this is somewhat subjective.

 

Here is NGC 6939. Conventionally, this is considered to have a small brightness range. But the reach of the intensifier changes that somewhat.

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[Jeff Morgan]

Many nebula have co-located open clusters. Sometimes I prefer the 12nm h-alpha filter so as not to kill-off the fainter cluster members. This is IC 410 and NGC 1893. With the image intensifier, central Auriga totally transforms.

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[gatorengineer]

Jeff a little off topic but have you been able to quantify the mag gain of nv no filters and then the loss with 12 7 and 3.5? As well as bandpass?  Doing some very rough guess with my Gen 2 and the 24 I was getting mid 13s and ideally the scope should be getting mid 16s...with NV.  Next time out I will see what it does no nv versus nv.. 

[Jeff Morgan]

Jeff a little off topic but have you been able to quantify the mag gain of nv no filters and then the loss with 12 7 and 3.5? As well as bandpass?  Doing some very rough guess with my Gen 2 and the 24 I was getting mid 13s and ideally the scope should be getting mid 16s...with NV.  Next time out I will see what it does no nv versus nv.. 

 

Unfiltered, I am pretty confident I am getting at least 2 magnitudes gain.

 

Filtered would depend upon the transmission of the filter - most line filters pass around 90% at the design wavelength. You do lose some light, but lose more of the undesired light.

 

Counting star fields is very tedious and error prone, so what I have been doing is looking for a globular cluster just on the edge of resolution because:

 

1) The "search area" is small and manageable; and

2) Accurate data is available on the brightest stars in those clusters via the Uranometria Deep Sky Field Guide.

 

One cluster that is close to qualifying is NGC 2419, aka the Intergalactic Wanderer. I can get 4-6 core stars resolved very consistently. USSFG gives the bightest stars as 17.4, and depending upon where you look, the theoretical magnitude for a 16" aperture is 15.4.

 

Of course you also need to factor in that this observation was not from some mountain top in the Sierra Nevadas or a remote Pacific Island - that is from my SQM 20.5 back yard. And I was not living in a cave for three days prior to that session, or breathing 100% oxygen, or eating beta carotene or any of those other silly things.

 

So I am confident that magnitude gain is at least 2.

 

An observer may say "well, using a 16" I can get down to magnitude X conventionally". That may very well be true - there are individual differences in performance levels for all human endeavors. And I would congratulate such a person for being on the upper-end of the Bell Curve for visual sensitivity. But the salient point is such a person would also get the same gain from a typical Gen 3 device as You or I (without having to do all of those dark adaption rituals). About 2+ magnitudes.

 

Here is another way to look at it:

 

https://www.cloudyni...n-i3/?p=3549132

Edited by Jeff Morgan, 11 June 2020 - 07:43 PM.

[Jeff Morgan]

After November of 2018 I got away from the cell phone photography thing for awhile, for a variety of reasons.

 

Some of those were specific to cell phone photography itself: lack of a reliable adapter, focus issues, and an older model phone. Also, I was not very systematic in my exploration of NightCap, the app iPhone users get for better control of the camera and in-app image averaging.

 

In September 2019 I found myself with some time off work due to tendon repair surgery. That months Phil Harrington Cosmic Challenge article happened to be about a nebula in Cygnus I was unfamiliar with - Simeis 57. 

 

The article sketch made from a 18" dob under dark skies was not encouraging. No way was I up for a dark sky trip six days after surgery, let alone setting up my 16" Dob.

 

OTOH, I possessed the Excalibur of Eyepieces. With my right arm in a sling and half-cast, I gave it a go in my 5" refractor from my SQM 20.5 back yard.

 

Simeis 57 is on my Favorites List now. The whole field is loaded with trails and feathers of nebulosity 

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[Scottsdale90]

Here are three more I took last week.  Bortle 1, 7100ft, seeing average.

 

All photos with TEC140ED, Mod 3C NV at prime focus with iPhone11 and Nightcap.

 

Gamma Cygni 0.75x GSO focal reducer (had to take out the diagonal) ISO1600 15 sec x 1.  Used an astronomik 6nm HA filter.

M81/82 no filter, ISO32 30sec x1.  Was happy to glimpse the spiral in M81.

North America and Pelican Nebulas an experiment where I stacked a 2" 0.75x GSO focal reducer and a 1.25" 0.5x GSO focal reducer. Used an astronomik 6nm HA filter. ISO 250 15sec x 1.  Severe vignetting but cool to see this wide a field with an F7 scope.  FWIW, I had earlier done a detailed comparison of prime focus vs afocal with TV55plossl and prefer the views at prime focus, despite the narrower field of view.

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[Jeff Morgan]

A little change of pace, an image through a Canon 300mm telephoto lens. Unguided, so I had to limit the averaging to 3 seconds.

 

It's a beautiful field. Unfortunately, the 12mb TIFF loses a lot in the compression to JPEG for the CN posting limit.

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[Jeff Morgan]

Newcomers to NV inevitably have questions on which filters to get. To a large extent, filter choice is based on personal preference. Here are a couple of photos with identical settings, the only difference being filter: 12nm vs. 7nm.

 

Note the difference in embedded cluster NGC 6996. It conveniently shows how narrower bandpass attenuates (or eliminates) background stars. OTOH, there is somewhat more nebulosity displayed. In this case, my preference is 12nm.

 

So, would I use 12nm all of the time? No. NGC 7000 is a fairly bright nebula. If it was a dimmer one, the tighter filter might be called for. Stronger light pollution would also drive me in that direction.

 

No substitute for getting out under the night sky and trying many variations. And having at least two filters to choose from 

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[Jeff Morgan]

Today's APOD is "The Tadpoles of IC 410".

 

Looking back at Post 90, even with the file compression required to post here, they are still visible!

 

Next winter I will make it a point to revisit this with perhaps a little more magnification.

[scottinash]

Amazing !

[Jeff Morgan]

Another view of dark nebula Barnard 186. But pop on a hydrogen alpha filter and surprise! A pot of nebula gold at the end of the dark nebula rainbow.

 

 

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Edited by Jeff Morgan, 19 June 2020 - 12:41 PM.

[Jeff Morgan]

Not too many people talk about NV and open clusters, but the results can be very good. Mainly it depends upon the nature of the cluster in question. And secondarily, on the focal length of the system. In this case, the 500mm of the Epsilon e180 was not enough! But, it was a pretty star field in Cygnus ...

 

 

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