OR: Night Vision, it's not just for nebula any more...

[Mark McCarthy]

As Richard mentioned, I was at Henry Coe Tuesday night the 16th as it seemed the best opportunity for a darker sky this new moon.  

I brought my C8, intending to use it in prime focus mode to view star clusters and galaxies.  With prime focus in the C8 I have 78x magnification and 0.5-degree field of view, unfiltered the whole night.  (I describe how I modified the device for prime focus at the end of this report, for those who might be interested.)

Once dark I ran through alignment on the AVX mount with Mirach as the last calibration star, and I immediately noticed NGC 404, Mirach's ghost, pretty bright oval with a bright central core.  It is an isolated dwarf lenticular galaxy around 10 mly distant, just outside our local group.  Off to a good start.

I ran through a number of open clusters to start, such as M52, NGC 129, and so on.  NGC 7789, Caroline's Rose, was especially beautiful and really does look like a rose, with semi-circular loops of bright and faint stars expanding from the center and folding into each other.  SQML was 20.4 once fully dark.

I then went through mostly galaxies, and I was very impressed with what I could see.  I had the sense I was seeing in the C8+NV what I had seen with my 20-inch from much darker skies.  

NGC 7331: Bright round core, like a ball floating on a frisbee, an effect of the contrast between the very elongated halo and subtle dark lanes on the near-side close to the core.  Flea NGC 7340 noticed immediately, well away from the galaxy, with NGC 7335 seen with slightly more effort, and smaller, fainter NGC 7336 noticed with considerably more effort.  NGC 7336 not noticed at all, nor the supernova, nor the very tiny NGC 7326 or NGC 7325 on the other side of the galaxy than the fleas.  Philip tried with his 17.5-inch, and I could pick out NGC 7340 pretty well, but not any others -- I may not have been dark adapted because of the night vision device.  Richard was able to see the three I mentioned.

Stephen's Quintet: 3 galaxies (NGC 7318, 7319, 7320) seen with certainty as in a triangle, with a sense of the area inside and around the triangle lumpenly brighter from the surrounding skies.  7318 was the brightest, elongated with a bright core, the other two were small soft irregular glows.

NGC 7549, 7550, 7547: Three galaxies forming an isosceles triangle.  7459 was a small non-stellar oval glow, oriented N-S next to a bright star.  7550 was fairly evenly bright, larger round glow.  7547 was small, elongated 3:1 ENE-WSW, with a bright stellar core.  

NGC 40, a planetary nebula, has a bright irregularly round shell which had brighter edges on either side of the outer shell, like parenthesis.  There was a gap between the bright central star and the shell, and outflows of nebula escaping the poles.  Most curiously, these outburst portions positively shimmered -- not from seeing, but as if by variations in light pulses.  I observed this twice at different times during the night, at different elevations, and the effect was the same.  I wonder if there is something going on astrophysically which would cause this effect?

NGC 1501: Prominent central star, faint round halo with crisp edges, forms a subtly irregularly round circle, with soft mottling inside the halo.

NGC 382 is in the center of a 14-galaxy group, most aligned in a N-S string.  I drew 5 galaxies in my sketchbook: 382, 380, 379, 385, 384, though a couple of what I took to be stars might have been small galaxies, but I didn't count those.  They all appeared as small elliptical glows of varying size, brightness, and orientation, and it was neat to see them in a string like that.

IC 342: a soft, moderately large round glow, seen best with gain turned down low.  I sense some swirling effect in the mottling, especially near the center bright stellar core, but it is very subtle.  NV does not do well with face-on galaxies.

NGC 891: This was very large, a bit more than the FOV, and very ghostly, seeming to float in the dense field of stars.  Faint, long, with a prominent dark lane down the center.  

NGC 910 group: Just a half degree to the southeast from NGC 891 is NGC 910 and friends, a string of five brighter NGC galaxies, plus a couple more very faint and small NGC and MCGs.  910 was the brightest by far, then leading north like breadcrumbs were 911, 909, 906, and 914 off to one side.  These all appeared as small elliptical glows in various orientations.

NGC 80 group: Another cluster of galaxies of which I saw eight: 80, 83, 90, 93, 79, 85, 86, 96 all as small elliptical glows, except for 90 which was slightly mottled and round.

NGC 772: This is a disrupted spiral and appeared so: a bright core off-center to a diffuse comma-shaped halo with a long bright arm, which I could clearly see, to the north.  Smaller, fainter elliptical NGC 770 was close by to the southwest. 

NGC 200 and others: Another string of galaxies, this time seven in the field of view (193, 204, 199, 194, 200, 198, 182), all pretty bright oval and round glows except for 199 which was smaller and fainter.

AGC 426, Perseus Galaxy Cluster: when centered on NGC 1272, I can see more than 15 galaxies in the field with direct vision, and a few more with averted vision.  Several bright ones, then smaller non-stellar glows appear.  This view more than anything convinces me the night vision device really does triple the effective aperture!  This is Albert Highe's "Birthday Cluster" which is familiar to many TACOs.

NGC 1023 / 1023A: One of the more dramatic galaxies seen.  Very large, bright, very long arms extending beyond the FOV, and swirly dark nebula around the core.  The eastern tip had a brightening which is elongated at a slight angle than the main galaxy, this is 1023A, its satellite galaxy.  Too bad Jamie wasn't there to have a look!

It was at this point I remembered how night vision does particularly well with flat galaxies, so I pulled out Alvin Huey's Flat Galaxy Observing Guide and observed some I hadn't looked at before:

NGC 100: Lovely long galaxy at least 8:1 NE-SW, with a bright central core and a halo which gently tapers to very fine tips.  Vmag 13.9, size 5.4 x 0.6'.

NGC 522: Small but bright, with a very bright core and long tapering tips, 6:1 NE-SW.  A string of 3 fine stars just north of the galaxy.  Bmag 13.9b, size 2.7 x 0.4'.  Did not notice IC 102.

IC 194: Difficult, very faint, small but very extended streak nearly N-S, slightly brighter round core.  Mag 15.2p, size 1.4 x 0.2'.

IC 176: Very difficult, extremely faint, needed to check the star pattern in the guide to locate it.  Small 4:1 E-W glow with a very faintly brighter core.

NGC 973, with IC 1815 in field: 193 looks like a smaller version of NGC 891, edge-on and bisected by a dark lane, 6:1 NE-SW, Mag 13.6p, size 3.7 x 0.6'.  IC 1815 was a small out-of-round glow with a brighter core.

NGC 1110: Extremely faint, needed to play with the gain setting to detect it: weak glow NNE-SSW, 5:1, very slightly brighter central region and diffuse, very faint tips.  Mag. 15.0 2.8 x 0.5' 

NGC 1145: Fairly easily seen, in an "L" shape asterism of three equal magnitude stars, 6:1 NE-SW, it has a compact bright core, and the halo is mottled -- I have the sense it is slightly inclined towards us showing some spiral structure.  Mag 13.6b 3.2 x 0.5' 

NGC 1163: Very faint, lays off of a triangle asterism.  Brighter bulging core region quickly fading to sharp tips.  Mag 14.7b, size 2.8 x 0.3' 

NGC 1247: Pretty bright, very bright core, mottled inner halo, diffuse tips, 6:1 ENE-WSW.  Mag. 13.5b 3.3 x 0.5'.

IC 2098: Extremely faint, small, 6:1 E-W, with a slightly brighter round core which bulges from the halo.  Mag 14.5, size 2.5 x 0.2' 

NGC 925: face-on barred spiral, appeared as a fairly large, faint mottled glow with a small bright core and a brighter smudge in the halo glow extending E-W from the core.   

NGC 253: Probably the sight of the night: Gigantic galaxy filling more than the field of view, very mottled halo with swirls of dark nebula around the core.

*  Over the last couple of years I've been using my PVS-14 night vision device with small refractors and fast focal length reflectors to view large-scale nebula.  The afocal arrangement (PVS-14 with 67mm eyepiece) allows wide fields and a large enough entrance pupil to the PVS-14 to better feed light into the sensor.  But I often wished I had better "image scale" or magnification to view smaller objects.  If I use a shorter focal length eyepiece instead of the 67mm, there is less light fed into the device which leads to scintillation (like TV static) and spoils the view.  One way to get around this is to use night vision in prime-focus mode, which fully illuminates the sensor, and the device is equivalent to a 26mm focal length eyepiece.  Most PVS-14s are set-up for afocal only, but by buying a couple of special threaded adapters and taking apart the device to remove a retaining ring, I can remove the PVS-14 objective and switch in between afocal and prime focus modes -- getting the most use out of the device.

[Ted Hauter]

Wow!!

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[Richard Navarrete]

Wonderful observing report. You were busy! The views through your scope were certainly impressive

Thanks for writing such a thorough OR.

Richard

Sent from the all new AOL app for iOS

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[Kurt Kuhlmann]

What device/ adapter do you recommend?  I'd like to try that

To view this discussion visit https://groups.google.com/d/msgid/sf-bay-tac/29358393.3183920.1758412689873%40mail.yahoo.com.

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Kurt Kuhlmann

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[Ted Hauter]

A pic of the set up would be great.

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[mccart...@yahoo.com]

Doing this will void your PVS-14 vendor's warranty, FYI.

You need to buy:

1) RAFCAMERA M42x0.75 (T2) female thread to PVS-14 mount adapter (link)

Also buy:

2) Baader T2 1.25” nosepiece (to insert into 1.25” focuser/diagonal/barlow) (link2)

3) Any vendor: T2 male to M48 Female adapter, plus a M48 M-F adapter ~30mm length (to use as a nosepiece to insert the assembly into 2” focuser/diagonal/barlow)

Optional to buy:

4) PVS-14 tool kit (link3).  I have this and can do this work on anyone's PVS-14 for a beer.

Youtube how-to videos to show how to disassemble / reassemble.  You need to remove the retaining ring which prevents the 1x objective from unscrewing from the housing.  (see 4:20 of video1).

video1

video 2

When you’re all done, you switch between afocal and prime by unscrewing the 1x objective from the PVS-14 body and screwing in the threaded adapter, as in this video3.  Just keep in mind when using that without a retainer there is nothing stopping you from adjusting the PVS-14's native focusing too much and unscrewing the assembly accidentally.

Another note of caution: Prime mode needs a good deal of in-focus (eg. need to move focuser toward your mirror/objective).  In my C8 I could only reach focus with a 1.25" visual back and diagonal; I could not focus with a 2" visual back/diagonal, nor could I reach focus using the 0.63 reducer and 1.25" visual back/diagonal.  I probably need to use the Baader T2 quick-change adapter with one of their 1.25" diagonals to focus with the reducer.  Also, my 20-inch f/5 Newtonian is optimized for visual, meaning long trusses and a small secondary, and I could not reach focus except by adding a 2" barlow.  If your Newtonian is optimized for photography, it could probably work.

One of the benefits of prime is that you can use any kind of barlow to get even more magnification -- so you're not fixed to it acting like a 26mm eyepiece only.  Add a barlow and power up (though get below a 10mm entrance pupil and you might have scintillation).  I didn't have any 1.25" barlows with me the other night so I didn't try.

And once you know how to do this, you can build your own PVS-14 by buying parts -- let's say you come across a super high-spec tube, you can now swap it in the body...

Good luck,

Mark

[mccart...@yahoo.com]

Sorry, how-to video2 shows the assembly of the 1x objective and the installation of the retaining ring--you'd be doing the reverse, removing this retaining ring.

Mark

[Kurt Kuhlmann]

Too many bits and bobs to stick together.  I sorted out the optics threads so 3D printed a screw-in 1 1/4"  adapter in nylon.  Will let you know when I get the disassembly kit how well it works.  At least this can get you as close in focus as possible but seems like the battery cap will hit first

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[Jamie Dillon, DDK]

Interesting set of objects you picked out, m'friend. From world famous top-of-the-line eye candy, like 1023 all the way to 253, then some really on-beyond zebra pinpricks. It's good that you're continuing to build your character.

[Jamie Dillon, DDK]

Here for contrast, what you're getting out of that NV setup, I went and looked at my notes for ngc 925, on a spectacular night at the Peak (LM 6.4, seeing 5/5), with Felix the 11",

"1023 group. Interesting object, like a puff of smoke caught between 3 stars, 2 on the north side, 1 on the south. Oriented kind of E-W, mildly brighter toward the middle."

And with your C8 you're seeing that it's a face-on barred spiral. That's impressive.

[Mark Scrivener]

Very impressive! I've been tempted by NV for a while but never took the leap. Given the Smarteye is now available at roughly the same cost, I wonder how the two would compare. In any case, I think the options for "assisted" viewing are only going to keep getting better.

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[Kurt Kuhlmann]

 at lick I can show people the central star of m57 in my 6" refractor.  It really does open things up

Kurt Kuhlmann

CEO

Amped Innovation - Powering Up the Pyramid

mobile: 408.390.6669

skype: kurtkuhlmann

www.ampedinnovation.com

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[Rod Brown]

This topic is really whetting my appetite for my own NVD. Thanks for sharing.

Rod